Pump body and ventricular assist device

Abstract

The present application relates to a kind of pump body and ventricular assist device.Pump body includes pump shell and impeller, wherein, pump shell is equipped with receiving cavity and liquid inlet hole, receiving cavity has first cavity surface, second cavity surface and the side ring surface connected between first cavity surface and second cavity surface, liquid inlet hole is through first cavity surface and is communicated with receiving cavity, side ring surface includes casing involute section, the center of base circle of casing involute section passes through the axis of liquid inlet hole, the distance of multiple points on casing involute section to center linearly increases along the involute direction of casing involute section;Impeller is rotatably arranged between first cavity surface and second cavity surface, the rotation axis of impeller is coaxial with the axis of liquid inlet hole.Such setting makes that the minimum distance between any point on casing involute section and the outer periphery surface of impeller and the minimum distance between the point 180 degrees apart from the point and the outer periphery surface of impeller is the difference value of fixed value, so that the radial force suffered by impeller in the process of rotation is substantially equal, improves the stability of impeller rotation, reduces the probability of impeller and pump shell collision.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a pump body and a ventricular assist device including the pump body. Background Technology

[0002] A ventricular assist device (VAD) is a device that assists heart failure patients in pumping blood. Blood flows out after the impeller of the VAD performs work, ensuring that the pumped blood meets the patient's requirements for blood flow and perfusion pressure. However, in traditional VADs, the impeller rotation is not stable enough during operation, causing the impeller to easily collide with the VAD housing, necessitating improvement. Summary of the Invention

[0003] One technical problem addressed by this invention is reducing blood contamination caused by collisions between the impeller and the pump casing. This invention solves the aforementioned technical problem through the following technical solution.

[0004] In a first aspect, the present invention provides a pump body, comprising:

[0005] The pump housing has a receiving cavity and an inlet hole. The receiving cavity has a first cavity surface, a second cavity surface, and a side annular surface connecting the first cavity surface and the second cavity surface. The inlet hole penetrates the first cavity surface and communicates with the receiving cavity. The side annular surface includes an involute section of the housing. The center of the base circle of the involute section passes through the axis of the inlet hole. The distance from a plurality of points on the involute section to the center of the base circle increases linearly along the involute direction of the involute section.

[0006] An impeller is rotatably disposed between the first cavity surface and the second cavity surface, and the rotation axis of the impeller is coaxial with the axis of the liquid inlet.

[0007] In one embodiment, the involute segment of the shell has a theoretical starting point located on the base circle, and the distance L1 from the point on the involute segment of the shell to the center of the circle satisfies: L1=R+aθ, where a>0, R is the radius of the base circle, and θ is the angle by which the line segment from the center of the circle to the theoretical starting point rotates about the center of the circle along the involute direction of the involute segment of the shell.

[0008] In one embodiment, the involute section of the shell has a starting point and an ending point, the center of the circle, the theoretical starting point, and the ending point are collinear, the line segment from the center of the circle to the ending point is a first line segment, and the line segment from the center of the circle to the starting point is a second line segment. The included angle α between the first line segment and the second line segment is 0°≤α≤40°.

[0009] In one of the embodiments, the pump housing further comprises a liquid outlet pipe, the liquid outlet pipe is provided with a liquid outlet hole in communication with the accommodating cavity, rotation of the impeller transports liquid entering from the liquid inlet hole to the liquid outlet hole, the distance between the theoretical starting point and the terminal point is L2, and the inner diameter of the liquid outlet pipe is D, wherein 3 / 4≤L2 / D≤1.

[0010] In one of the embodiments, the pump body further comprises a partition plate, the partition plate is connected to at least one of the first cavity surface and the second cavity surface, and the partition plate is arranged between the outer peripheral surface of the impeller and the side ring surface.

[0011] In one of the embodiments, the inner surface of the partition plate comprises a partition involute segment surrounding the base circle, any straight line passing through the center of the base circle has a first intersection point with the housing involute segment and a second intersection point with the partition involute segment, and the distance from the first intersection point to the center is equal to the distance from the second intersection point to the center.

[0012] In one of the embodiments, the housing involute segment has a starting point, a terminal point and a theoretical starting point located on the base circle, the center, the theoretical starting point and the terminal point are collinear, the first line segment from the center to the terminal point also passes through the terminal point of the partition involute segment, the second line segment from the center to the starting point, and the third line segment from the center to the starting point of the partition involute segment, along the involute direction of the housing involute segment, the rotation angle of the second line segment to the third line segment around the center is β, wherein 180°≤β<270°.

[0013] In one of the embodiments, the pump housing further comprises a liquid outlet pipe, the liquid outlet pipe is provided with a liquid outlet hole in communication with the accommodating cavity, the starting point of the housing involute segment is connected to one end of the hole wall of the liquid outlet hole close to the accommodating cavity.

[0014] In one of the embodiments, the inner surface of the partition plate further comprises a partition straight line segment, the partition straight line segment is connected to the terminal point of the partition involute segment, and the partition straight line segment has a preset length extending towards the liquid outlet hole.

[0015] In the second aspect, the application further provides a ventricular assist device, comprising a motor and the pump body of any one of the above-mentioned embodiments, the motor is connected to the pump body, and the motor can generate a rotating magnetic field to drive the impeller to rotate.

[0016] Compared to existing technologies, the pump body and ventricular assist device provided by this invention include a pump casing and an impeller. The pump casing has a receiving cavity and an inlet hole. The side annular surface of the receiving cavity includes an involute section of the casing, and the center of the base circle of the involute section passes through the axis of the inlet hole. Since the distance from multiple points on the involute section of the casing to the center increases linearly along the involute direction of the involute section, the difference between the distance from any point on the involute section of the casing to the center and the distance from a point on the involute section of the casing 180 degrees away to the center is a constant. The rotation axis of the impeller is coaxial with the axis of the inlet hole, making the difference between the minimum distance between any point on the involute section of the casing and the outer circumferential surface of the impeller and the minimum distance between a point 180 degrees away from that point and the outer circumferential surface of the impeller a constant. The radial hydraulic force on the impeller originates from the pressure difference between the minimum distance from any point on the impeller's circumference to the side surface of the pump casing and the minimum distance from a point 180 degrees away to the side surface of the pump casing. The larger the difference, the greater the pressure difference and the greater the radial force on the impeller. Therefore, the distances from points on multiple involute sections of the casing to the center increase linearly along the involute direction of the casing, and the impeller's rotation axis is coaxial with the axis of the inlet hole. This ensures that the radial force on the impeller during rotation is approximately equal, improving the stability of impeller rotation and reducing the probability of collision between the impeller and the pump casing. Attached Figure Description

[0017] Figure 1 A perspective view of the ventricular assist device provided by the present invention;

[0018] Figure 2 for Figure 1 A front view of the ventricular assist device shown;

[0019] Figure 3 for Figure 2 A sectional view along the XX direction;

[0020] Figure 4 for Figure 1 A perspective view of the top shell of the ventricular assist device shown;

[0021] Figure 5 for Figure 4 The top view of the top shell shown;

[0022] Figure 6 for Figure 1 A top view of the top shell and impeller of the ventricular assist device shown;

[0023] Figure 7 for Figure 1 A three-dimensional view of the impeller of the ventricular assist device shown;

[0024] Figure 8 for Figure 7 The impeller shown is a front view. Detailed Implementation

[0025] For the purposes of promoting an understanding of the principles of the application, reference will now be made to the embodiments illustrated in the drawings. There is shown by way of illustration a preferred embodiment of the application. It is to be understood that the application can be practiced with modification and alteration, and can take on various forms. Accordingly, the embodiments are set forth only for the purpose of illustration and are not intended as a limitation on the application, together with changes in the drawings detailing them, which can present themselves to those with or without the benefit of practice or knowledge.

[0026] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can also be present. The terms "inner," "outer," "left," "right," and similar terms as used herein are for descriptive purposes only and not meant to be limiting.

[0027] The inventor of the present application found that in the working process of the conventional ventricular assist device, when the impeller rotates in a non-contact suspended manner relative to the pump shell, there is usually an imbalance in the radial force acting on the impeller, which causes the impeller to produce a large amplitude of yawing during rotation, and then causes the impeller to collide with the pump shell, affecting the suspended state of the impeller and also causing damage to the blood.

[0028] In order to improve at least some of the above problems, the present application provides a pump body and a ventricular assist device, which can make the radial force acting on the impeller during rotation substantially equal, improve the stability of the rotation of the impeller, and reduce the probability of collision between the impeller and the pump shell.

[0029] Referring to Figures 1 to 5 The pump body 11 of the ventricular assist device 10 provided by the present application includes a pump shell 100 and an impeller 200. The pump shell 100 is provided with a receiving cavity 101 and a liquid inlet hole 102. The receiving cavity 101 has a first cavity surface 110, a second cavity surface 120, and a side ring surface 130 connected between the first cavity surface 110 and the second cavity surface 120. The liquid inlet hole 102 penetrates the first cavity surface 110 and communicates with the receiving cavity 101. The side ring surface 130 includes a plurality of shell involute segments 131. The center of the base circle 400 of the shell involute segment 131 passes through the axis of the liquid inlet hole 102, and the distance from the center to the points on the plurality of shell involute segments 131 increases linearly along the involute direction of the shell involute segment 131. The impeller 200 is rotatably arranged between the first cavity surface 110 and the second cavity surface 120, and the rotation axis of the impeller 200 is coaxial with the axis of the liquid inlet hole 102. The rotation axis of the impeller 200 refers to the axis of the impeller 200 when the impeller 200 does not yaw during rotation.

[0030] In the present embodiment, the distance from each point on the housing involute segment 131 to the center of the circle linearly increases along the involute direction of the housing involute segment 131, and the distance from each point on the housing involute segment 131 to the center of the circle is a constant value minus the distance from a point 180 degrees apart from the point on the housing involute segment 131 to the center of the circle, wherein the involute direction of the housing involute segment 131 is consistent with the rotation direction of the impeller 200. Since the hydraulic radial force on the impeller 200 is caused by the pressure difference between the minimum distance from any point on the impeller 200 to the side surface 130 of the pump housing and the minimum distance from a point 180 degrees apart from the point on the impeller 200 to the side surface 130 of the pump housing, the greater the difference, the greater the pressure difference, and the greater the radial force on the impeller 200. Therefore, the distance from each point on the housing involute segment 131 to the center of the circle linearly increases along the involute direction of the housing involute segment 131, and the rotation axis of the impeller 200 is coaxial with the axis of the inlet hole 102, so that the difference between the minimum distance from any point on the housing involute segment 131 to the outer circumferential surface of the impeller 200 and the minimum distance from a point 180 degrees apart from the point on the housing involute segment 131 to the outer circumferential surface of the impeller 200 is a constant value. Therefore, the radial force on the impeller 200 during rotation is approximately equal, improving the stability of the rotation of the impeller 200 and reducing the probability of collision between the impeller 200 and the pump housing 100.

[0031] When the distance from each point on the housing involute segment 131 to the center of the circle non-linearly increases along the involute direction of the housing involute segment 131, such as exponentially, logarithmically or other ways, the difference between the distance from each point on the housing involute segment 131 to the center of the circle and the distance from a point 180 degrees apart from the point on the housing involute segment 131 to the center of the circle cannot be a constant value. Therefore, the radial force on the impeller 200 during rotation changes, causing the rotation of the impeller 200 to be unstable. Therefore, compared with the conventional pump body, the pump body 11 of the present application improves the stability of the rotation of the impeller 200 by linearly increasing the distance from each point on the housing involute segment 131 to the center of the circle along the involute direction of the housing involute segment 131, so that the radial force on the impeller 200 during rotation is approximately equal.

[0032] In the embodiment, the housing involute segment 131 has a theoretical starting point 1310 on the base circle 400, and the distance L1 from a point on the housing involute segment 131 to the center of the base circle 400 satisfies L1 = R + aθ, where a > 0, R is the radius of the base circle 400, and θ is the angle of the line segment from the center of the base circle 400 to the theoretical starting point 1310 rotating around the center of the base circle 400 along the involute direction of the housing involute segment 131. Since L1 = R + aθ, there is a linear relationship between L1 and θ, and as θ increases, the distance L1 from a point on the housing involute segment 131 to the center of the base circle 400 also increases, i.e., the distance from a point on the housing involute segment 131 to the center of the base circle 400 linearly increases along the involute direction of the housing involute segment 131. For example, the radius of the base circle 400 is 5 mm, and the distance from the intersection point of the extension line of the line segment formed after the line segment from the center of the base circle 400 to the theoretical starting point 1310 rotates 5° around the center of the base circle 400 to the center of the base circle 400 is 5.2 mm, the distance from the intersection point of the extension line of the line segment formed after the line segment from the center of the base circle 400 to the theoretical starting point 1310 rotates 10° around the center of the base circle 400 to the center of the base circle 400 is 5.4 mm, the distance from the intersection point of the extension line of the line segment formed after the line segment from the center of the base circle 400 to the theoretical starting point 1310 rotates 15° around the center of the base circle 400 to the center of the base circle 400 is 5.6 mm, and so on. The distance from a point on the housing involute segment 131 to the center of the base circle 400 linearly increases along the involute direction of the housing involute segment 131, so that the difference between the distance from any point on the housing involute segment 131 to the center of the base circle 400 and the distance from the point 180° apart from the point on the housing involute segment 131 to the center of the base circle 400 is a constant value, thereby the radial force on the impeller 200 during rotation is substantially equal, and the stability of the rotation of the impeller 200 is improved.

[0033] In one embodiment, the pump body 11 further comprises a partition plate 300 connected to at least one of the first cavity surface 110 and the second cavity surface 120, and the partition plate 300 is arranged between the outer peripheral surface of the impeller 200 and the side ring surface 130, so that the partition plate 300 can divide the space between the housing involute segment 131 and the impeller 200 into two relatively independent channels, one of which is between the housing involute segment 131 and the partition plate 300, and the other of which is between the partition involute segment 310 and the impeller 200, and blood can flow in the two channels respectively, Figure 4The arrows and dotted arrows respectively represent the flow trajectories of blood in the two channels. The blood located in the channel between the separation involute section 310 and the impeller 200 will generate pressure on the impeller 200, while the blood located in the channel between the housing involute section 131 and the partition 300 cannot generate pressure on the impeller 200 due to the isolation of the partition 300. Therefore, by arranging the partition 300, the blood pressure in the channel between the housing involute section 131 and the partition 300 can be reduced to interfere with the impeller 200, thereby further improving the stability of the rotation of the impeller 200 and further reducing the probability of collision between the impeller 200 and the pump shell 100.

[0034] The inner surface of the partition 300 includes a separation involute section 310 surrounding the base circle 400. Any straight line (such as straight line 610 in Figure 5 FIG. 6) passing through the center of the base circle 400 has a first intersection point 611 with the housing involute section 131 and a second intersection point 612 with the separation involute section 310. The distance from the first intersection point 611 to the center is equal to the distance from the second intersection point 612 to the center. For ease of description, any straight line passing through the center of the base circle 400 will be described below with the straight line 610 as an example.

[0035] Please refer to Figure 7 FIG. 6, the distance from the first intersection point 611 to the center is equal to the distance from the second intersection point 612 to the center, and the rotation axis of the impeller 200 is coaxial with the axis of the liquid inlet hole 102. Therefore, when the impeller 200 rotates, the blood flows in the gap between the housing involute section 131 and the impeller 200 and in the gap between the separation involute section 310 and the impeller 200. Since the rotation axis of the impeller 200 is coaxial with the axis of the liquid inlet hole 102, the straight line 610 has a first intersection point 611 with the housing involute section 131 and a second intersection point 612 with the separation involute section. The distances from the first intersection point 611 and the second intersection point 612 to the center are equal. Therefore, the distance from the first intersection point 611 to the impeller 200 along the straight line 610 is equal to the distance from the second intersection point 612 to the impeller 200 along the straight line 610. The width of the first gap G1 between the housing involute section 131 and the impeller 200 at the first intersection point 611 is equal to the width of the second gap G2 between the separation involute section 310 and the impeller 200 at the second intersection point 612. Thus, the pressure generated by the blood on the impeller 200 at the first gap G1 and the second gap G2 is equal, and the forces in the radial direction of the impeller 200 are balanced, thereby reducing the radial runout of the impeller 200 during rotation, further reducing the collision between the impeller 200 and the top shell 103, and reducing the damage to the blood by the impeller 200. The ventricular assist device 10 provided by the application will be described in detail below in combination with the specific embodiments and the accompanying drawings.

[0036] Please refer to Figure 1 , Figure 2 andFigure 3 The ventricular assist device 10 provided by an embodiment of the present application comprises a pump body 11 and a motor 12, and the pump shell 100 of the pump body 11 comprises a top shell 103, a bottom shell 104, a liquid inlet pipe 105 and a liquid outlet pipe 106.

[0037] The bottom shell 104 is fixed on the motor 12, and the top shell 103 is arranged on the bottom shell 104. The top shell 103 and the bottom shell 104 can be connected by detachable connection or integrally connected by integral molding. The top shell 103 and the bottom shell 104 jointly form a receiving cavity 101. A first cavity surface 110 is arranged on the top shell 103, and the liquid inlet hole 102 is arranged on the top shell 103 in view of the fact that the liquid inlet hole 102 penetrates through the first cavity surface 110. A second cavity surface 120 is arranged on the bottom shell 104. The impeller 200 is received in the receiving cavity 101 and located between the first cavity surface 110 and the second cavity surface 120. The motor 12 is used to drive the impeller 200 to rotate. In the process of rotation of the impeller 200, the motor 12 generates a magnetic suspension force on the impeller 200 through a magnetic field force, so that the impeller 200 rotates in a non-contact suspension manner relative to the top shell 103 and the bottom shell 104.

[0038] The liquid inlet pipe 105 and the liquid outlet pipe 106 are both arranged on the top shell 103. The liquid inlet pipe 105 is fixed on the top shell 103 at a position corresponding to the liquid inlet hole 102. The liquid outlet pipe 106 is provided with a liquid outlet hole 1061. The liquid outlet hole 1061 communicates with the receiving cavity 101. The impeller 200 is coaxially arranged with the liquid inlet hole 102. When the ventricular assist device 10 pumps blood, the blood first enters the liquid inlet pipe 105, then enters the receiving cavity 101 through the liquid inlet hole 102, and finally flows out of the artificial blood vessel through the liquid outlet hole 1061, thereby realizing the blood pumping function of the ventricular assist device 10.

[0039] Referring to Figure 3 , Figure 4 and Figure 5 In some embodiments, the partition plate 300 can be arranged on the first cavity surface 110 of the top shell 103. In other embodiments, the partition plate 300 can also be arranged on the second cavity surface 120 of the bottom shell 104, or the partition plate 300 can be arranged on both the first cavity surface 110 and the second cavity surface 120.

[0040] Referring to Figure 4 and Figure 5With the axis of the liquid inlet hole 102 as the center of a circle, the side surface 130 of the accommodation cavity 101 includes a housing involute section 131, which can be formed by a generating line rolling purely on the base circle 400. The generating line can be understood as a straight line that is always tangent to the base circle 400. Obviously, the housing involute section 131 has an origin point on the base circle 400, which can be understood as a theoretical starting point 1310 of the housing involute section 131. The theoretical starting point 1310 is also the tangent point of the generating line before pure rolling on the base circle 400. The two ends of the housing involute section 131 are the starting point and the ending point, respectively. For the convenience of description, the starting point of the housing involute section 131 is denoted as a first starting point 1311, and the ending point of the housing involute section 131 is denoted as a first ending point 1312. The first starting point 1311 is connected to one end of the hole wall of the liquid outlet hole 1061 close to the accommodation cavity 101.

[0041] Referring to Figure 4 and Figure 5 In some embodiments, the center of the circle to the first ending point 1312 is a first line segment 510, which passes through the theoretical starting point 1310 and the first ending point 1312 of the housing involute section 131, i.e., the center of the circle, the theoretical starting point 1310, and the first ending point 1312 are collinear.

[0042] The center of the circle to the first starting point 1311 is a second line segment 520. The included angle between the first line segment 510 and the second line segment 520 is α, and the value of α ranges from 0° to 40°. The specific value of α can be 0°, 10°, 30°, or 40°, etc. The included angle α can be understood as the angle of rotation of the first line segment 510 around the center of the circle along the developing direction of the housing involute section 131. In fact, when α is greater than 40°, the hole diameter of the liquid outlet hole 1061 is relatively large, the flow field speed in the liquid outlet hole 1061 is too low, the flushing effect is poor, and blood clots are easily formed due to the accumulation of blood in the liquid outlet hole 1061. When the value of α ranges from 0° to 40°, the blood in the liquid outlet hole 1061 has a reasonable flow field speed, which improves the flushing effect of the blood, thereby effectively avoiding the formation of blood clots in the liquid outlet hole 1061.

[0043] Referring to Figure 4 and Figure 5In some embodiments, the distance between the theoretical starting point 1310 and the first ending point 1312 of the shell involute segment 131 is L2, the inner diameter of the outflow pipe 106 is D, and the value of L2 / D is in the range of 3 / 4≤L2 / D≤1. The distance between the theoretical starting point 1310 and the first ending point 1312 is less than the inner diameter of the outflow pipe 106. In this way, the pressure of the blood flowing from the accommodation cavity 101 to the outflow pipe 106 through the outflow hole 1061 is reasonably increased, so as to pressurize the blood and improve the perfusion function of the auxiliary heart. In fact, when the value of L2 / D is less than 3 / 4, the diffusion angle from the cross section passing through the theoretical starting point 1310 and the first ending point 1312 to the outlet cross section of the outflow pipe 106 is too large, which reduces the hydraulic efficiency and is not conducive to the pressurization of the blood. When the value of L2 / D is greater than 1, there is no diffusion angle from the cross section passing through the theoretical starting point 1310 and the first ending point 1312 to the outlet cross section of the outflow pipe 106, which is also not conducive to the pressurization of the blood.

[0044] Referring to Figure 4 and Figure 5 In some embodiments, the inner surface of the partition plate 300 includes a partition involute segment 310, which shares the same base circle 400 with the shell involute segment 131. However, the starting point of the partition involute segment 310 and the theoretical starting point 1310 of the shell involute segment 131 are located at different positions on the base circle 400, i.e., the theoretical starting point of the partition involute segment 310 and the theoretical starting point 1310 of the shell involute segment 131 are located at different positions on the base circle 400 and are separated by a certain angle along the circumference of the base circle 400. The two ends of the partition involute segment 310 are the starting point and the ending point, respectively. For the convenience of description, the starting point of the partition involute segment 310 is referred to as the second starting point 311, and the ending point of the partition involute segment 310 is referred to as the second ending point 312. The third line segment 530 is from the center to the starting point of the partition involute segment 310, and the first line segment 510 passes through the second ending point 312 of the partition involute segment 310, so the first line segment 510 also passes through the theoretical starting point 1310, the first ending point 1312 and the second ending point 312 of the shell involute segment 131. With the rotation angle of the third line segment 530 around the center along the involute direction of the partition involute segment 310 as the reference, the distance from the intersection point of the third line segment 530 and the partition involute segment 310 to the center increases linearly with the increase of the rotation angle, so that the partition involute segment 310 satisfies the characteristic of involute.

[0045] The second starting point 311 is spaced apart from the first starting point 1311 by an angle along the circumference of the base circle 400, and the second line segment 520 coincides with the third line segment 530 by rotating an angle β along the direction of the development of the housing development segment 131 about the center of the circle, in other words, the second line segment 520 rotates to the third line segment 530 by an angle β about the center of the circle, and the value of β is in the range of 180°≤β<270°, for example, the specific value of β can be 180°, 200° or 245°, etc., and the rotation angle β can also be understood as the interval angle of the second starting point 311 and the first starting point 1311 along the circumference of the base circle 400. In view of the fact that the second starting point 311 is spaced apart from the first starting point 1311 by an angle along the circumference of the base circle 400, the straight line 610 has a first intersection point 611 with the housing development segment 131, and the straight line 610 has a second intersection point 612 with the separation development segment 310, so that the center of the base circle 400 is located between the first intersection point 611 and the second intersection point 612. The distance from the center of the circle to the first intersection point 611 and the second intersection point 612 is equal.

[0046] Without the separation plate 300, in view of the fact that the impeller 200 is coaxially arranged with the liquid inlet hole 102, the side surface 130 of the accommodation cavity 101 includes the housing development segment 131, and along the circumference of the base circle 400, the gap between the housing development segment 131 and the impeller 200 is not equal, the greater the interval angle of the position on the housing development segment 131 and the first starting point 1311 along the circumference of the base circle 400, the greater the gap between the position and the impeller 200, the straight line 610 has a first intersection point and a second intersection point with the housing development segment 131, so that the first gap G1 between the housing development segment 131 and the impeller 200 at the first intersection point is not equal to the second gap G2 between the housing development segment 131 and the impeller 200 at the second intersection point 612, resulting in that the pressure of the blood on the impeller 200 at the first gap G1 and the second gap G2 is not equal, thereby causing the impeller 200 to be unbalanced in the radial direction, and finally causing the impeller 200 to produce a radial deflection. Under the influence of the radial deflection, the impeller 200 will collide with the top cover 103, thereby destroying the suspension state of the impeller 200 and also damaging the blood by the impeller 200.

[0047] For the pump body 11 in the above embodiment, the separation plate 300 can separate the space between the housing development segment 131 and the impeller 200 that is far apart into two relatively independent channels, one of which is located between the housing development segment 131 and the separation plate 300, and the other of which is located between the separation development segment 310 and the impeller 200, and the blood can flow in the two channels respectively, Figure 4The arrows and dotted arrows represent the flow trajectories of the blood in the two passages respectively. The blood in the passage between the separation involute section 310 and the impeller 200 will generate pressure on the impeller 200, while the blood in the passage between the housing involute section 131 and the partition 300 cannot generate pressure on the impeller 200 due to the isolation of the partition 300, thereby reducing the interference of the blood pressure in the passage between the housing involute section 131 and the partition 300 on the impeller 200.

[0048] Meanwhile, since any straight line (such as the straight line 610) passing through the center of the base circle 400 has a first intersection point 611 with the housing involute section 131 and a second intersection point 612 with the separation involute section 310, the distances from the first intersection point 611 and the second intersection point 612 to the center of the base circle 400 are equal. When the impeller 200 rotates, the blood flows in the passages between the housing involute section 131 and the impeller 200 and between the separation involute section 310 and the impeller 200, and the distance from the first intersection point 611 to the impeller 200 along the straight line 610 is equal to the distance from the second intersection point 612 to the impeller 200 along the straight line 610. The width of the first gap G1 between the housing involute section 131 and the impeller 200 at the first intersection point 611 is equal to the width of the second gap G2 between the separation involute section 310 and the impeller 200 at the second intersection point 612, so that the pressure generated by the blood at the first gap G1 and the second gap G2 is equal, and the forces of the impeller 200 in the radial direction will cancel each other out, thereby achieving the force balance of the impeller 200 in the radial direction, reducing the radial eccentricity of the impeller 200 during rotation, and then reducing the probability of collision between the impeller 200 and the top cover 103, and reducing the damage of the impeller 200 to the blood.

[0049] Referring to Figure 4 and Figure 5In some embodiments, the second line segment 520 coincides with the third line segment 530 by rotating an angle β around the center of the circle along the developing direction of the shell developing segment 131, and β is in the range of 180°≤β<270°, for example, β can be 180°, 240° or 260°, etc. β can also be understood as the angle between the second starting point 311 and the first starting point 1311 along the developing direction of the shell developing segment 131 in the circumferential direction of the base circle 400. The developing direction of the shell developing segment 131 can also be understood as the counterclockwise direction. Take the straight line where the diameter of the base circle 400 is located as the reference straight line 620, and the reference straight line 620 passes through the first starting point 1311. When β is equal to 180°, the reference straight line 620 also passes through the second starting point 311. During the counterclockwise rotation of the reference straight line 620 by 180°, the reference straight line 620 will always have intersection points with the shell developing segment 131 and the separation developing segment 310 at the same time, so that the radial force of the impeller 200 during rotation is completely balanced, i.e., the radial force of the impeller 200 is zero. When β is greater than 180°, the reference straight line 620 where the diameter of the base circle 400 is located cannot pass through the second starting point 311, so that the second starting point 311 is separated from the reference straight line 620 by a certain angle in the circumferential direction of the base circle 400. During the counterclockwise rotation of the reference straight line 620 to intersect the second starting point 311, the reference straight line 620 cannot intersect the separation developing segment 310. The part of the reference straight line 620 that does not intersect the separation developing segment 310 can be understood as the blank segment corresponding to the shell developing segment 131. The part of the impeller 200 corresponding to the blank segment in the circumferential direction cannot achieve good force balance in the radial direction. Specifically, the intersection point of the reference straight line 620 and the shell developing segment 131 is E, the intersection point of the extension line of the third line segment 530 and the shell developing segment 131 is F, and the part of the shell developing segment 131 between the intersection point E and the intersection point F can be understood as the blank segment corresponding to the shell developing segment 131.

[0050] In some embodiments, the first line segment 510 coincides with the third line segment 530 by rotating an angle γ around the center of the circle along the developing direction of the shell developing segment 131, and γ is in the range of 180°+α≤γ<270°, for example, γ can be in the range of 225°≤γ<270°, and γ can be 225°, 245° or 260°, etc. γ can be understood as the angle between the second starting point 311 and the theoretical starting point 1310 of the shell developing segment 131 in the circumferential direction of the base circle 400 in the counterclockwise direction. In view of the above range of γ, the second starting point 311 can not be located on the above-mentioned reference straight line 620, so that the second starting point 311 is separated from the reference straight line 620 by a certain angle in the circumferential direction of the base circle 400, thereby reasonably reducing the length of the separation developing segment 310 and the entire separation plate 300.

[0051] When the length of the partition plate 300 is greater, the area of the partition plate 300 is greater, and the risk of thrombosis caused by the adhesion of the partition plate 300 to the protein in the blood is higher. Therefore, in order to reduce the risk of thrombosis, the length of the partition plate 300 needs to be as short as possible. However, in order to well balance the radial force of the impeller 200, the second starting point 311 needs to be located on the reference straight line 620, and the length of the partition plate 300 cannot be too short. In order to reasonably solve the above-mentioned contradiction, by limiting the value range of γ, the best balance effect between balancing the radial force of the impeller 200 and reducing the risk of thrombosis can be achieved.

[0052] In some embodiments, the inner surface of the partition plate 300 further comprises a partition straight line segment 320 connected with the second terminal point 312 of the partition involute segment 310, and the partition straight line segment 320 is perpendicular to the first line segment 510 and extends to the outlet hole 1061 by a preset length. The side surface 130 of the accommodation cavity 101 further comprises a housing straight line segment 132 connected with the first terminal point 1312 of the housing involute segment 131, and the housing straight line segment 132 is perpendicular to the first line segment 510 and extends to the outlet hole 1061 by a preset length. By arranging the partition straight line segment 320 and the housing straight line segment 132, the blood flowing in the passages between the housing involute segment 131 and the impeller 200 and between the partition involute segment 310 and the impeller 200 can be more smoothly converged to the outlet hole 1061 to flow out, so as to prevent the blood from generating turbulence during the convergence process and affecting the balance of the impeller 200.

[0053] Referring to Figure 7 and Figure 8 In some embodiments, the impeller 200 comprises a mounting plate 210 and a blade 220. The mounting plate 210 has a first surface 2111 and a second surface 212 in the thickness direction. The blade 220 is arranged on the second surface 212. The first surface 2111 comprises a bearing surface 2111 and an inclined surface 2112, both of which are annular. The bearing surface 2111 and the inclined surface 2112 are arranged around the axis of the impeller 200. The bearing surface 2111 is arranged around the inclined surface 2112, so that the inclined surface 2112 is closer to the axis of the impeller 200 than the bearing surface 2111, that is, the inclined surface 2112 is located on the inner side of the bearing surface 2111. The bearing surface 2111 is arranged horizontally and perpendicularly to the axis of the impeller 200. The inclined surface 2112 is arranged obliquely to the axis of the impeller 200 and towards the blade 220. Specifically, from one end of the inclined surface 2112 close to the bearing surface 2111 to the other end of the inclined surface 2112 away from the bearing surface 2111, the distance of the inclined surface 2112 to the second surface 212 decreases. The number of mounting plates 210 can be two, and the blade 220 is connected between the second surfaces 212 of the two mounting plates 210. Of course, the number of mounting plates 210 can also be one.

[0054] The angle between the ramp surface 2112 and the bearing surface 2111 is θ, wherein 1°≤θ≤2°, and the specific value of θ can be 1°, 1.5° or 2°, etc. The ratio of the difference between the inner diameter and the outer diameter of the ramp surface 2112 to the difference between the inner diameter and the outer diameter of the first surface 211 is 1 / 2-1, and the specific value of the ratio can be 1 / 2 or 1, etc. When the ratio is 1, the first surface 211 is entirely the ramp surface 2112.

[0055] By arranging the bearing surface 2111 and the ramp surface 2112, and the ratio of the difference between the inner diameter and the outer diameter of the ramp surface 2112 to the difference between the inner diameter and the outer diameter of the first surface 211 is 1 / 2-1, 1°≤θ≤2°, the pressure of the blood acting on the first surface 211 can be well controlled, thereby reducing the axial force borne by the impeller 200 as a whole, improving the stability of the impeller 200 on the shaft during rotation, reducing the shaking of the impeller 200 in the axial direction, and also enabling the blood pressure to generate sufficient supporting force on the impeller 200, so that the impeller 200 has a good suspension state, reduces the collision between the impeller 200 and the top shell 103 and the bottom shell 104, and further reduces the damage to the blood caused by the collision between the impeller 200 and the pump shell 100.

[0056] In summary, the pump body 11 of the ventricular assist device 10 provided by the application comprises a pump shell 100 and an impeller 200. The pump shell 100 is provided with a receiving cavity 101 and a liquid inlet hole 102. The receiving cavity 101 has a first cavity surface 110, a second cavity surface 120 and a side surface 130 connected between the first cavity surface 110 and the second cavity surface 120. The liquid inlet hole 102 penetrates the first cavity surface 110 and communicates with the receiving cavity 101. The side surface 130 comprises a plurality of housing involute segments 131. The center of the base circle 400 of the housing involute segments 131 passes through the axis of the liquid inlet hole 102. The distance from each point on the housing involute segments 131 to the center of the base circle 400 linearly increases along the involute direction of the housing involute segments 131. Therefore, the difference between the distance from any point on the housing involute segments 131 to the center of the base circle 400 and the distance from a point 180 degrees apart from the point on the housing involute segments 131 to the center of the base circle 400 is a constant value. The impeller 200 is rotatably arranged between the first cavity surface 110 and the second cavity surface 120. When the impeller 200 rotates, the blood flows between the housing involute segments 131 and the impeller 200, and between the partition involute segments 310 and the impeller 200. Since the distance from each point on the housing involute segments 131 to the center of the base circle 400 linearly increases along the involute direction of the housing involute segments 131, and the rotation axis of the impeller 200 is coaxial with the axis of the liquid inlet hole 102, the difference between the minimum distance from any point on the housing involute segments 131 to the outer periphery surface of the impeller 200 and the minimum distance from a point 180 degrees apart from the point on the housing involute segments 131 to the outer periphery surface of the impeller 200 is a constant value. Therefore, the radial force borne by the impeller 200 during rotation is approximately equal, which improves the stability of the rotation of the impeller 200 and reduces the probability of collision between the impeller 200 and the pump shell 100.

[0057] Any combination of the technical features in the above-described embodiments can be made. For the sake of brevity, the description herein has not described all possible combinations of the technical features in the above-described embodiments, however, it is understood that any combination of the technical features is within the scope of the present disclosure as long as the combination does not result in a contradiction.

[0058] The above-described embodiments only express several embodiments of the present application, which are described in a more specific and detailed manner, but should not be understood as a limitation on the scope of the patent. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these are within the scope of protection of the present application. Therefore, the scope of protection of the present patent should be subject to the appended claims.

Claims

1. A pump body, characterized by, The pump comprises: a pump housing provided with a receiving cavity and a liquid inlet hole, the receiving cavity having a first cavity surface, a second cavity surface and a side surface connecting between the first cavity surface and the second cavity surface, the liquid inlet hole penetrating through the first cavity surface and communicating with the receiving cavity, the side surface comprising a plurality of housing involute segments, the center of the base circle of the housing involute segments passing through the axis of the liquid inlet hole, the distance from the center of the base circle to the points on the housing involute segments linearly increasing along the involute direction of the housing involute segments, the difference between the distance from the center of the base circle to the point on the housing involute segment and the distance from the center of the base circle to the point on the housing involute segment 180 degrees away from the point being a constant value; a impeller rotatably arranged between the first cavity surface and the second cavity surface, the rotation axis of the impeller coaxial with the axis of the liquid inlet hole; and a partition plate connected to at least one of the first cavity surface and the second cavity surface, the partition plate arranged between the outer circumferential surface of the impeller and the side surface, the inner surface of the partition plate comprising a plurality of partition involute segments surrounding the base circle, any straight line passing through the center of the base circle having a first intersection point with the housing involute segments and a second intersection point with the partition involute segments, the distance from the center of the base circle to the first intersection point being equal to the distance from the center of the base circle to the second intersection point. The housing involute segment has a theoretical starting point on the base circle, the distance L1 from the center of the base circle to the point on the housing involute segment satisfying L1=R+aθ, where a>0, R is the radius of the base circle, and θ is the angle of the line segment from the center of the base circle to the theoretical starting point rotating around the center of the base circle along the involute direction of the housing involute segment.

2. The pump body of claim 1, wherein The housing involute segment further has a starting point and an ending point, the center of the base circle, the theoretical starting point and the ending point being collinear, the first line segment from the center of the base circle to the ending point and the second line segment from the center of the base circle to the starting point having an included angle α satisfying 0°≤α≤40°.

3. The pump body of claim 2, wherein, The pump housing further comprises a liquid outlet pipe provided with a liquid outlet hole communicating with the receiving cavity, the rotation of the impeller conveying the liquid entering from the liquid inlet hole to the liquid outlet hole, the distance between the theoretical starting point and the ending point being L2, and the inner diameter of the liquid outlet pipe being D, where 3 / 4≤L2 / D≤1.

4. The pump body of claim 3, wherein, The impeller comprises a mounting plate and blades, the mounting plate having a first surface and a second surface along the thickness direction, the blades arranged on the second surface, the first surface comprising a load surface and an inclined surface both in the form of a ring, the load surface and the inclined surface arranged around the axis of the impeller, the load surface arranged around the inclined surface, and the inclined surface closer to the axis of the impeller than the load surface.

5. The pump body of claim 1, wherein From one end of the inclined surface close to the load surface to the other end of the inclined surface away from the load surface, the distance from the inclined surface to the second surface decreases, and the included angle between the inclined surface and the load surface is θ, where 1°≤θ≤2°.

6. The pump body of claim 5, wherein, ​ 7. The pump body of claim 1, wherein The housing involute section has a starting point, an ending point and a theoretical starting point on the base circle, the center of the circle, the theoretical starting point and the ending point are collinear, the first line segment from the center of the circle to the ending point also passes through the ending point of the separating involute section, the second line segment from the center of the circle to the starting point, the third line segment from the center of the circle to the starting point of the separating involute section, the rotation angle of the second line segment to the third line segment around the center of the circle is β in the involute direction of the housing involute section, wherein 180°≤β<270°.

8. The pump body of claim 1, wherein The pump housing further comprises a liquid outlet pipe provided with a liquid outlet hole in communication with the receiving cavity, and the starting point of the housing involute section is connected with the hole wall of the liquid outlet hole close to one end of the receiving cavity.

9. The pump body of claim 8, wherein, The inner surface of the partition plate further comprises a separating straight line section connected with the ending point of the separating involute section, and the separating straight line section has a preset length extending towards the liquid outlet hole.

10. A ventricular assist device, characterized by The pump body of any one of claims 1 to 9, and a motor connected to the pump body, wherein the motor is capable of generating a rotating magnetic field to drive the impeller to rotate.

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