Conduit pump and pump body thereof

Abstract

The application discloses a conduit pump and a pump body and an impeller thereof. The impeller can be accommodated in a pump shell of the conduit pump and comprises a hub and blades provided on the hub. The blades have blade roots provided on the hub, blade tips away from the hub, and reverse folding portions between the blade roots and the blade tips. The blade roots extend in a first circumferential direction and tilt towards the reverse folding portions in a radial direction. The reverse folding portions extend in a second circumferential direction opposite to the first circumferential direction and tilt towards the blade tips of the blades in the radial direction.

Description

[0001] This application is a divisional application of application No. "202111436271.8", with a filing date of "November 29, 2021", and with the title of "Catheter pump and impeller and pump body thereof". TECHNICAL FIELD

[0002] The present disclosure relates to the field of medical devices, in particular to a device for cardiac assist use, and more particularly to a catheter pump and impeller and pump body thereof. BACKGROUND

[0003] An interventional catheter pump device (hereinafter referred to as a blood pump) can pump blood. Taking left ventricular assist as an example, the prior art generally places the pump of the interventional catheter pump device in the left ventricle of the subject's body, and drives the impeller of the pump to rotate through a flexible shaft, and drives the flexible shaft through a motor to transmit power to the pump.

[0004] In order to ensure stable contraction and expansion, the existing catheter pump can be inserted into the blood vessels of the patient and can be expanded after insertion. During compression and expansion, the rotor (for example, the impeller) and the shell will deform accordingly, and the stability of the tip clearance size (also known as the pump gap, that is, the interval gap between the radial outer end of the impeller and the inner wall of the pump body shell) is an important factor affecting the stability of the blood pump. Through simulation analysis, the size change of the pump body external support (shell) is small, and the greatest influence on the tip clearance is the change of the outer diameter of the impeller.

[0005] As the rotational speed increases, the outer diameter of the impeller continues to increase, and the continuous increase of the outer diameter of the impeller will rapidly improve the hydraulic performance, and the improvement of the hydraulic performance will in turn promote the increase of the impeller diameter, which leads to a small range of stable and efficient work of the impeller, and has a negative impact on the efficiency of the pump.

[0006] Furthermore, as the rotational speed increases, the continuous increase of the outer diameter of the impeller is likely to exceed the design working point, resulting in scraping between the impeller and the support and failure of the blood pump. SUMMARY

[0007] In view of the above shortcomings, one object of the present disclosure is to provide a catheter pump and impeller and pump body thereof capable of reducing the change in the outer diameter of the impeller during work rotation.

[0008] Another object of the present disclosure is to provide a catheter pump and impeller and pump body thereof capable of stably maintaining the pump gap.

[0009] To achieve at least one of the above objects, the present application adopts the following technical solutions:

[0010] A kind of impeller for conduit pump, the impeller can be contained in the pump shell of the conduit pump rotates, including hub and the blade being arranged on hub.Blade has top, the root being arranged on hub and between root and top the reverse fold portion.Root extends obliquely in the radial direction along the first circumferential direction to the reverse fold portion, and the reverse fold portion extends obliquely in the radial direction along the second circumferential direction opposite to the first circumferential direction to the top of blade.The first circumferential direction is opposite to the direction of rotation of impeller.

[0011] Preferably, the impeller has a natural unfolded state when not rotating and a working state corresponding to maximum working speed when rotating.The outer diameter of the top (the outer diameter of the impeller) changes less than 0.5 mm, preferably less than 0.3 mm, and further preferably less than 0.1 mm when the impeller switches from the natural unfolded state to the working state.Further, the outer diameter of the top changes less than 0.3 mm, and further preferably less than 0.1 mm when the impeller switches from the minimum working speed to the maximum working speed in the working state.

[0012] Preferably, the blade includes a first portion between the root and the reverse fold portion, and a second portion between the reverse fold portion and the top.The radial length La of the first portion is greater than 0.5 times the radial length of the second portion, and preferably the radial length La of the first portion is greater than the radial length of the second portion.

[0013] Preferably, the blade includes a first portion between the root and the reverse fold portion, and a second portion between the reverse fold portion and the top.The blade has an inward concave leading surface and an outward convex trailing surface, and the maximum thickness of the second portion is greater than 0.7 times the maximum thickness of the first portion, and further, the maximum thickness of the second portion is greater than the maximum thickness of the first portion.The thickness direction is the normal direction of the profile line of the inward concave leading surface or the outward convex trailing surface in the cross section.

[0014] Preferably, the blade includes a first portion between the root and the reverse fold portion, and a second portion between the reverse fold portion and the top.The cross-sectional area of the first portion is greater than 0.5 times, and preferably 0.8 times the cross-sectional area of the second portion.

[0015] Preferably, in a cross section of the blade, the blade includes a first portion between the root and the reverse fold portion, and a second portion between the reverse fold portion and the top.The tangent line of the reverse fold portion passes through the center of the hub;The length of the first portion in the direction perpendicular to the tangent line is greater than 0.3 times, and preferably 0.5 times the length of the second portion in the direction perpendicular to the tangent line.

[0016] Preferably, the blade comprises a first portion between the blade root and the reverse bend, and a second portion between the reverse bend and the blade tip; the blade has an inner concave pressure surface and an outer convex suction surface facing away from each other; wherein any point on the inner concave pressure surface or the outer convex suction surface of the first portion has a tangent line defined by a tangent vector pointing away from the second portion The tangent line of the any point has a contact point with the outer profile line of the hub, and the center of the hub has a radial vector pointing towards the contact point The tangent vector And the radial vector The angle β between them is greater than 90 degrees and less than 180 degrees.

[0017] Preferably, the closer the position point on the inner concave pressure surface or the outer convex suction surface of the first portion to the reverse bend, the greater the angle β. Preferably, the blade root has a circular arc transition between the inner concave pressure surface and the hub, and / or the blade root has a circular arc transition between the outer concave suction surface and the hub.

[0018] A blade wheel for a conduit pump, the blade wheel being rotatable accommodated in a pump housing of the conduit pump, comprising a hub and a blade arranged on the hub. The blade has a blade tip, a blade root arranged on the hub, and a reverse bend between the blade root and the blade tip. On a cross section where the blade has a maximum outer diameter, the blade root of the blade extends radially towards the reverse bend along a first circumferential direction opposite to a rotation direction of the blade wheel; the reverse bend extends radially towards the blade tip of the blade along a second circumferential direction opposite to the first circumferential direction.

[0019] A blade wheel for a conduit pump, the blade wheel being rotatable accommodated in a pump housing of the conduit pump; the blade wheel comprises a hub and a blade arranged on the hub. The blade has a blade tip, and a blade root arranged on the hub. When the blade wheel switches from a minimum working speed to a maximum working speed in a working state, the outer diameter of the blade tip changes by less than 0.3mm. Further, the outer diameter of the blade tip changes by less than 0.1mm.

[0020] A pump body of a conduit pump, the pump body having a pump housing with a blood outlet and a blood inlet, a blade wheel accommodated in the pump housing and being controllably rotatable to pump blood from the blood inlet to the blood outlet; the pump body has a radially collapsed state suitable for being delivered into or in a vasculature of a subject, a natural expanded state corresponding to a non-rotating state of the blade wheel, and a working state corresponding to a rotating state of the blade wheel. In a process of switching the pump body from the natural expanded state to the working state, the blade wheel is configured to have an outer diameter change of less than 0.5mm, preferably less than 0.3mm, and further preferably less than 0.1mm.

[0021] Preferably, the blade wheel is configured to have an unchanged or increased outer diameter of less than 0.3mm.

[0022] Preferably, the pump housing comprises a covering membrane defining the blood flow channel and a support frame supporting the covering membrane; the impeller is accommodated in the support frame; during the switching of the pump body from the natural expansion state to the working state, the support frame is configured not to participate in causing elastic deformation and plastic deformation of the covering membrane, or, in the working state of the pump body, the support frame is configured not to participate in causing elastic deformation and plastic deformation of the covering membrane.

[0023] Preferably, during the switching of the pump body from the natural expansion state to the working state, the increase rate of the outer diameter of the support frame is not more than 1%.

[0024] Preferably, during the switching of the pump body from the natural expansion state to the working state, the deformation of the covering membrane does not exceed the elastic deformation limit thereof, or, in the working state of the pump body, the deformation of the covering membrane does not exceed the elastic deformation limit thereof.

[0025] Preferably, the impeller comprises a hub fixedly sleeved on the impeller shaft and blades provided on the hub; the blades have blade roots provided on the hub and blade tips away from the hub; the pump gap is defined between the blade tips and the inner wall of the support frame; the gap width of the pump gap in the radial direction is less than 1.5 mm.

[0026] Preferably, during the switching of the pump body from the natural expansion state to the working state, the change amount of the gap width of the pump gap in the radial direction is less than 0.5 mm.

[0027] Preferably, the pump body of the catheter pump comprises the impeller of any one of the above.

[0028] A catheter pump comprises a motor, a drive shaft penetrating in a catheter and in transmission connection with the output shaft of the motor, and a pump body capable of pumping blood to a desired position of a heart through the catheter. The pump body comprises the impeller of any one of the above and a pump housing accommodating the impeller, or the pump body of any one of the above; the pump housing of the pump body is connected to the distal end of the catheter, and the impeller is connected to the distal end of the drive shaft.

[0029] By adopting the scheme of the embodiment, the first part inside the reverse folding part of the blade of the impeller of the embodiment is used to balance the radial expansion amount of the second part outside the reverse folding part, the parts with different extension directions inside and outside are arranged by arranging the reverse folding part, the radial diameter change generated during rotation is balanced, the transition change of the outer diameter of the impeller due to the increase of the rotation speed is reduced, the hydraulic performance of the impeller can be kept stable, and the impeller can continuously and stably work efficiently when working in the working speed range.

[0030] The outer diameter change amount of the impeller of the embodiment remains unchanged or is located in a smaller change range in the working speed range, has a better stable outer diameter keeping capability, makes the blood pump keep the stability of working in a wider speed range, matches the performance and the speed, and improves the usability of the blood pump. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 This is a three-dimensional schematic diagram of a conduit pump provided in one embodiment of the present disclosure;

[0032] Figure 2 yes Figure 1 A schematic diagram of the pump casing;

[0033] Figure 3 This is a schematic diagram of a pump casing provided in another embodiment of this disclosure;

[0034] Figure 4 yes Figure 3 The main view;

[0035] Figure 5 yes Figure 4 A schematic diagram of the support structure;

[0036] Figure 6 yes Figure 5 The main view;

[0037] Figure 7 yes Figure 6 AA cross-section view;

[0038] Figure 8 This is a perspective view of a bracket provided in another embodiment of this disclosure;

[0039] Figure 9 yes Figure 8 Cross-sectional view;

[0040] Figure 10 yes Figure 1 Partial schematic diagram;

[0041] Figure 11 yes Figure 10 A schematic diagram of the bracket and impeller assembly;

[0042] Figure 12 yes Figure 10 Impeller assembly diagram;

[0043] Figure 13 yes Figure 12 A three-dimensional schematic diagram of the impeller;

[0044] Figure 14 yes Figure 13 Side view;

[0045] Figure 15 yes Figure 10 A sectional view of the pump body;

[0046] Figure 16 yes Figure 15 AA cross-section view.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1, power assembly; 2, coupling; 3, conduit; 4, pump body; 5, non-invasive support; 6, distal bearing chamber; 106, blood inlet; 320, proximal bearing chamber; 310, drive shaft; 355, impeller shaft;

[0049] 100, covering; 101, conical section; 102, distal end of covering; 103, cylindrical section; 105, blood outlet;

[0050] 200, stent; 201, stent section; 202, proximal end of conical stent; 203, distal end of conical stent; 204, connecting leg; 2041, stem; 2042, leg end; 205, connecting sub-tube; 210, connecting hole; 211, positioning buckle; 300, anti-expansion element;

[0051] 410, impeller; 411, blade; 412, hub; 418, pressure surface; 419, suction surface; A, first portion; B, second portion; D2, outer inflection point; D3, inner inflection point; 450, trajectory circle; 4111, tip; 4112, root; 4113, constant outer diameter section; 4115, transition line; 4116, transition point; 4121, proximal end of hub; 4122, distal end of hub. DETAILED DESCRIPTION

[0052] In order to make the personnel in the technical field better understand the technical solutions in the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in combination with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative labor should belong to the protection scope of the present disclosure.

[0053] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can be a middle element between them. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be a middle element between them. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description of the disclosure herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0055] The terms "proximal", "distal" and "anterior", "posterior" are relative to the clinician who manipulates the catheter pump. The terms "proximal", "posterior" refer to the parts relatively close to the clinician, and the terms "distal", "anterior" refer to the parts relatively far from the clinician. For example, the extracorporeal part is proximal and posterior, and the intracorporeal part of the intervention is distal and anterior.

[0056] The catheter pump of the embodiments of the present application is used for assisting heart failure, pumping blood to the heart to achieve partial blood pumping function of the heart. In the scenario suitable for left ventricular assistance, the catheter pump pumps blood from the left ventricle into the aorta to provide support for blood circulation, reduce the workload of the subject's heart, or provide additional continuous pumping power support when the heart's pumping capacity is insufficient.

[0057] Of course, the catheter pump can also be inserted into other target positions of the subject, such as the right ventricle, blood vessels, or other organs, according to the intervention of the interventional surgery.

[0058] Please refer to Figure 1 、 Figure 2 The catheter pump of the embodiments of the present disclosure includes a power assembly 1 and a working assembly. The power assembly 1 includes a housing and a motor received in the housing and having an output shaft, and the working assembly includes a catheter 3, a drive shaft 310 arranged in the catheter 3, and a pump body 4.

[0059] The pump body 4 can be delivered through the catheter 3 to the desired position of the heart, such as the left ventricle, to pump blood, including a pump shell having a blood inlet 106 and a blood outlet 105, and an impeller 410 received in the pump shell. The motor is arranged at the proximal end of the catheter 3, connected to the catheter 3 through the coupler 2, and drives the impeller 410 to rotate and pump blood through the drive shaft 310. The pump shell of the pump body 4 is connected to the distal end of the catheter 3, and the impeller 410 is connected to the distal end of the drive shaft 310.

[0060] The pump shell includes a covering film 100 defining a blood flow channel, and further includes a stent 200 for supporting the expansion of the covering film 100, and the proximal end of the stent 200 is connected to the distal end of the catheter 3. The proximal end of the stent 200 is provided with a connecting secondary tube 205, and a connecting hole 210 constituting a female buckle is arranged on the connecting secondary tube 205, forming a buckle type mechanical connection structure with the catheter 3.

[0061] The blade 411 is made of a flexible elastic material, which stores energy when being folded, and releases the stored energy to unfold the blade 411 when the external constraint is removed. The plurality of blades 411 are evenly arranged in the circumferential direction.

[0062] As shown in Figures 12-14 , the blade 411 is arranged closer to the distal end 4122 on the hub 412. The blade 411 has an outer diameter constant section 4113. The blade 411 has a leading edge (first water entry edge) and a trailing edge (second water entry edge) at the two axial ends thereof. The outer diameter constant section 4113 is located between the leading edge and the trailing edge and extends in a curve therebetween. The outer diameter of the outer diameter constant section 4113 is the maximum outer diameter of the blade 411. The outer diameter constant section 4113 and the leading edge and the trailing edge have transition sections 4116 therebetween, which can be rounded structures. The outer diameter constant section 4113 has a length of more than 0.5 times, or even more than 0.8 times the length of the blade 411. The outer diameter constant section has transition lines 4115 at the two ends thereof. The blade tip 4111 has a blade tip edge extending in a curve in the axial direction. The blade tip edge extends between the leading edge (first water entry edge) and the trailing edge (second water entry edge). The blade tip 4111 (blade tip end) forms a circular trajectory (trajectory circle 450) when the blade 411 rotates. The outer diameter of the impeller 410, the outer diameter of the blade tip 4111, or the diameter on which the blade tip 4111 is located is the diameter of the circular trajectory.

[0063] As shown in Figures 10-16 , the impeller 410 can be accommodated in the pump housing of a conduit pump and rotate therein. The impeller 410 includes a hub 412 and a plurality of blades 411 arranged on the hub 412. The blade 411 has a blade root 4112 arranged on the hub 412, a blade tip 4111 away from the hub 412, and a reverse fold D2D3 between the blade root 4112 and the blade tip 4111 (blade tip end). The blade root 4112 of the blade 411 extends in a first circumferential direction in the radial direction and inclines towards the reverse fold D2D3. The reverse fold D2D3 extends in a second circumferential direction opposite to the first circumferential direction in the radial direction and inclines towards the blade tip 4111 of the blade 411. The first circumferential direction is opposite to the rotation direction of the impeller 410. The second circumferential direction is the same as (parallel to) the rotation direction of the impeller 410.

[0064] As shown in Figure 16 , the blade 411 has an inner concave flow face 418 and an outer convex back flow face 419 opposite to each other. The flow face 418 of the blade 411 is concave, and the back flow face 419 is convex. The blade 411 has at least one cross section (cross section perpendicular to the axial direction), which is a C-shaped structure. In the cross section, the blade root 4112 of the blade 411 extends in a first circumferential direction in the radial direction and inclines towards the reverse fold D2D3. The reverse fold D2D3 extends in a second circumferential direction opposite to the first circumferential direction in the radial direction and inclines towards the blade tip 4111 of the blade 411.

[0065] At the cross section where the blade 411 has the maximum outer diameter. The cross section is taken from the outer diameter constant section 4113. Preferably, any cross section of the outer diameter constant section 4113 has a reverse fold D2D3, which forms corresponding reverse fold position points D2, D3 on the inner and outer surfaces (inner and outer profiles). The reverse fold D2D3 forms a continuous outer reverse fold line composed of the outer reverse fold position point D2 at the back flow surface 419, and forms a continuous inner reverse fold line composed of the inner reverse fold position point D3 at the front flow surface 418. The blade root 4112 of the blade 411 extends radially and in a first circumferential direction towards the reverse fold D2D3. The reverse fold D2D3 extends radially and in a second circumferential direction opposite to the first circumferential direction towards the blade tip 4111 of the blade 411.

[0066] The blade 411 includes a first portion A between the blade root 4112 and the reverse fold D2D3, and a second portion B between the reverse fold D2D3 and the blade tip 4111. The first portion A and the second portion B extend radially as a whole, and extend in opposite circumferential directions.

[0067] The inventor has found that, when the impeller 410 rotates, the first portion A and the second portion B are respectively subjected to a rotating centrifugal force, a reaction force from the fluid acting on the blade 411, fluid back pressure, and other forces. Under the combined action of the multiple forces (combined forces), the first portion A and the second portion B extend in opposite circumferential directions, and thus have different effects. The second portion B on the radially outer side of the first portion A expands to some extent in the radial direction under the combined action, so that the impeller 410 has a tendency to increase in diameter. The first portion A on the radially inner side of the second portion B contracts to some extent in the radial direction under the combined action, so that the blade 411 has a tendency to decrease in diameter.

[0068] Among them, the reaction force (resistance) from the fluid acting on the blade 411 is the main force. The first circumferential direction in which the first portion A extends is substantially parallel to the direction of the reaction force. When the reaction force acts on the first portion A, it presses the first portion A downward towards the hub 412, promoting the movement of the first portion A towards the hub 412, and forming a contraction trend. The second circumferential direction in which the second portion B extends is substantially opposite to the direction of the reaction force. When the reaction force acts on the second portion B, it pushes the second portion B outward, promoting the radial expansion of the second portion B, and forming an expansion trend.

[0069] Therefore, the blade 411 of the impeller 410 in the embodiment balances the radial expansion of the second part B outside the reverse fold D2D3 by the first part A inside the reverse fold D2D3, balances the radial diameter change generated during rotation by setting the parts with different extension directions inside and outside the reverse fold D2D3, reduces the transition change of the outer diameter of the impeller 410 due to the increase of the rotation speed, and can keep the hydraulic performance of the impeller 410 stable, so that the impeller 410 can work stably and efficiently in a stable and efficient manner in the working speed range.

[0070] The outer diameter change amount of the impeller 410 in the working speed range is kept unchanged or in a smaller change range, has a better stable outer diameter keeping ability, keeps the stability of the blood pump in a wider speed range, matches the performance and speed in a linear manner, and improves the usability of the blood pump.

[0071] In the embodiment, the outer diameter change amount of the impeller 410 is small during rotation, and the pump gap can be kept stable during the working process of the conduit pump. Specifically, the pump gap is defined between the blade top 4111 and the inner wall of the bracket 200. The gap width of the pump gap in the radial direction is less than 1.5 mm.

[0072] The impeller 410 has a natural unfolded state when not rotating and a working state when rotating at a maximum working speed. When the impeller 410 switches from the natural unfolded state to the working state, the diameter change amount of the blade top 4111 is less than 0.5 mm, that is, the outer diameter change amount of the impeller 410 is in the range of ±0.5 mm (the outer diameter increase amount is within 0.5 mm, and the outer diameter decrease amount is within 0.5 mm). Preferably, the outer diameter change amount of the impeller 410 is less than 0.3 mm (in the range of ±0.3 mm), and more preferably, the outer diameter change amount of the impeller 410 is less than 0.1 mm (in the range of ±0.1 mm).

[0073] It is worth noting that the above numerical values include all values from the lower limit value to the upper limit value in increments of one unit, and there is at least a two-unit interval between any lower value and any higher value.

[0074] For example, the outer diameter change amount of the impeller 410 is in the range of ±0.5 mm, preferably ±0.3 mm, and more preferably ±0.1 mm, which is to illustrate the above-mentioned values such as +0.08, -0.05, and ±0.03, which are not explicitly listed.

[0075] As mentioned above, the example range with an interval of 0.1 does not preclude growth with intervals of appropriate units such as 0.01, 0.02, 0.03, 0.04, 0.05, etc. These are merely examples intended to clarify the point, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0076] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0077] Other limitations on numerical ranges mentioned in this article can be found in the above description and will not be repeated here.

[0078] like Figure 16 As shown, the radial (projected) length La of the first part A is greater than 0.5 times the radial (projected) length Lb of the second part B. That is, the radial length La of the first part A is greater than 0.5 times the radial length of the second part B, La > 0.5Lb. Preferably, the radial (projected) length La of the first part A is greater than the radial (projected) length Lb of the second part B.

[0079] In some embodiments, the thickness of the blade 411 in the first part A is greater than the thickness of the blade 411 in the second part B. The first part A has a more stable structure than the second part B, thereby increasing the structural strength of the blade 411 to ensure fluid pumping efficiency. In this embodiment, the maximum thickness of the second part B is greater than 0.7 times the maximum thickness of the first part A. The thickness direction is the normal direction of the contour line of the concave upstream surface 418 or the convex downstream surface 419 on the cross-section. Furthermore, the maximum thickness of the second part B is greater than the maximum thickness of the first part A. Thus, by increasing the thickness of the second part B, its resistance to deformation is improved, preventing outward expansion and thereby stabilizing the outer diameter of the impeller 410.

[0080] To balance the radial variations of the first part A and the second part B and stably maintain the outer diameter of the impeller 410, the cross-sectional area of ​​the first part A is at least 0.5 times that of the second part B. Preferably, the cross-sectional area of ​​the first part A is at least 0.8 times that of the second part B. The cross-sectional area of ​​the first part A is less than 1.2 times that of the second part B. By increasing the proportion of the first part A and decreasing the proportion of the second part B, the radial variations of the first part A and the second part B are balanced, thereby balancing the proportion of the second part B.

[0081] Furthermore, such as Figure 16As shown, on a cross-section of blade 411, the tangent of the folded portion D2D3 passes through the center O of hub 412. The length H1 of the first portion A in the direction perpendicular to the tangent OO2 is more than 0.3 times the length H2 of the second portion B in the direction perpendicular to the tangent OO2, preferably more than 0.5 times H2.

[0082] On a cross-section of the impeller 410, the outwardly convex backflow surface 419 has a position point D2. The tangent OO2 of this position point passes through the center O of the hub 412, wherein the cross-section of the blade 411 is located on one circumferential side of the tangent OO2. Alternatively, a straight line is defined passing through this position point and the center of the hub 412, wherein the entire cross-section of the blade 411 is located on one circumferential side of this straight line. Position point D2 is located between the blade root 4112 and the blade tip 4111, and this position point is the outwardly folded position point D2 formed by the folded portion D2D3 on the contour of the cross-section.

[0083] like Figure 16 As shown, for any point located on the concave or convex frontal surface 418 of the first part A, the tangent at that point is defined to have a tangent vector that is away from the direction of the second part B. The tangent at any point has a contact point with the outer contour of the hub 412, and the center of the hub 412 is defined as having a ray vector pointing towards the contact point. Tangent vector and ray vector The angle β between the two is greater than 90 degrees and less than 180 degrees. The closer the position point on the concave or convex frontal surface 418 of the first part A is to the fold D2D3, the larger the angle β is.

[0084] The blade root 4112 has an arc-shaped transition section between the concave frontal surface 418 and the hub 412, and / or, the blade root 4112 has an arc-shaped transition section between the concave frontal surface 418 and the hub 412. The radius of curvature of the arc-shaped transition section is smaller than the radius of curvature of the first part A.

[0085] Following the description above, the impeller 410 is operably rotated within the pump housing to pump blood from the blood inlet 106 to the blood outlet 105. The pump body 4 has a radially constricted state suitable for intervention in or delivery within the vascular system of a subject, a naturally unfolded state corresponding to the impeller 410 not rotating, and an operating state corresponding to the impeller 410 rotating.

[0086] In the process of switching the pump body 4 from the natural expanded state to the working state, the impeller 410 is configured to have a change in the outer diameter of less than 0.5 mm. That is, the change in the outer diameter of the impeller 410 is within a range of ±0.5 mm. Preferably, the impeller 410 is configured to have a change in the outer diameter of less than 0.3 mm, and more preferably, the impeller 410 is configured to have a change in the outer diameter of less than 0.1 mm. The impeller 410 is configured to have an unchanged or increased outer diameter of less than 0.3 mm.

[0087] Further, the working state of the impeller 410 can be a working state at the maximum working rotational speed (maximum rotational speed). Thus, in the process of switching the pump body 4 from the natural expanded state (the impeller 410 is static) to the maximum rotational speed working state, the impeller 410 is configured to have a change in the outer diameter of less than 0.5 mm.

[0088] In the present embodiment, the pump housing has a small change in the inner diameter during the working rotation of the impeller 410, and the impeller 410 is configured to have an increased outer diameter of not more than 1% in the process of switching the pump body 4 from the natural expanded state to the working state. Specifically, the deformation of the covering membrane 100 is not more than the elastic deformation limit of the covering membrane 100 in the process of switching the pump body 4 from the natural expanded state to the working state, or the deformation of the covering membrane 100 is not more than the elastic deformation limit of the covering membrane 100 in the working state of the pump body 4.

[0089] As described above, the pump housing includes the covering membrane 100 defining the blood flow channel and the stent 200 for supporting the expanded covering membrane 100. The tip gap is located between the tip 4111 of the impeller 410 and the inner wall of the foldable stent 200. In other embodiments, the covering membrane 100 is integrated with the stent 200, for example, the covering membrane 100 is integrated with a helical support body, and the tip gap (pump gap) is located between the inner wall of the covering membrane 100 and the tip 4111.

[0090] In the process of switching the pump body 4 from the natural expanded state to the working state, the pump gap has a change in the gap width H3 in the radial direction of less than 0.5 mm, and further less than 0.3 mm. Specifically, the impeller 410 has an increased outer diameter of not more than 0.3 mm in the process of rotating from static to the maximum working rotational speed. The impeller 410 has a change in the outer diameter of within 0.3 mm in the working rotational speed range (for example, 10000-30000 rpm). The impeller 410 has a change in the outer diameter of within 0.3 mm, and further within 0.1 mm, in the process of rotating from the minimum working rotational speed (10000 rpm) to the maximum working rotational speed (30000 rpm), so as to stabilize the pump gap.

[0091] In the embodiment, the bracket 200 can be arranged inside the covering film 100 or outside the covering film 100. The impeller is arranged inside the bracket 200 and the covering film 100, the bracket 200 is supported at the distal end 102 of the covering film 100, and part of the bracket 200 is arranged outside the distal end 102 of the covering film 100, and the other part of the bracket 200 is arranged inside the covering film 100.

[0092] When the bracket 200 applies the unfolding force to the covering film 100, the covering film 100 does not produce elastic deformation and plastic deformation, and the covering film 100 has better anti-deformation ability. Further, the shape is better maintained during the blood pumping process, and cooperates with the impeller which is stably maintained in shape, so as to maintain the constant pump gap and maintain the pump efficiency at the best working efficiency.

[0093] The covering film 100 has a cylindrical segment 103 as a main structure and a conical segment 101 at the proximal end of the cylindrical segment 103, and the proximal end of the conical segment 101 is sleeved outside the catheter 3 and fixed to the outer wall of the catheter 3. The catheter 3 is connected to the proximal end of the bracket 200 through a proximal bearing chamber at the distal end thereof, and a proximal bearing for rotationally supporting the driving shaft 310 is arranged in the proximal bearing chamber. In one embodiment, the connecting pipe 205 directly forms the proximal bearing chamber and positions and fixes the proximal bearing through the positioning buckle 211.

[0094] The distal end of the bracket 200 is provided with a distal bearing chamber 6, and a distal bearing for rotationally supporting the distal end of the driving shaft 310 is arranged in the distal bearing chamber 6. The bracket 200 maintains the distance between the proximal bearing chamber 320 and the distal bearing chamber 6, thereby providing stable rotational support for the driving shaft 310. The driving shaft 310 includes a flexible shaft arranged in the catheter 3 and a hard shaft 355 (impeller shaft 355) connected to the distal end of the flexible shaft, and the hub 412 of the impeller 410 is sleeved on the hard shaft 355. The proximal end and the distal end of the hard shaft 355 are respectively arranged in the proximal bearing and the distal bearing. By means of the hard shaft 355 and the bearings at both ends, stable strength support is provided for the impeller in the pump housing, and the position of the impeller in the pump housing is stably maintained.

[0095] The coupler 2 is connected to the proximal end of the catheter 3, and a liquid flow channel is provided between the catheter 3 and the flexible shaft. The perfusion liquid input through the liquid flow channel can provide lubrication for the rotation of the flexible shaft and avoid heat generation due to rotation friction. The coupler 2 is provided with a perfusion liquid input portion 20 in communication with the liquid flow channel, and the perfusion liquid input portion 20 is in communication with the liquid flow channel. The distal end of the coupler 2 is provided with a retaining sleeve 260 for the catheter 3 to pass through, and the retaining sleeve 260 can fix the catheter 3.

[0096] The distal end of the distal bearing chamber 6 is connected with a non-invasive support 5. The non-invasive support 5 is a flexible tube structure, which is in the form of a flexible protrusion with a circular arc or winding shape at the end, so that the non-invasive support 5 supports on the inner wall of the heart chamber in a non-invasive or non-injurious manner, separates the blood inlet 106 of the pump body 4 from the inner wall of the heart chamber, and avoids the suction inlet of the pump body 4 from being attached to the inner wall of the heart chamber due to the reaction force of the blood during the operation of the pump body 4, thereby ensuring the effective area of the pump suction.

[0097] The pump housing includes a radially collapsed state suitable for intervention in the vasculature of a subject or delivery in the vasculature of a subject, a natural expanded state corresponding to the non-rotation of the impeller, and a working state corresponding to the rotation of the impeller. During the switching of the pump housing from the radially collapsed state to the natural expanded state, or during the switching from the natural expanded state to the working state, the deformation of the covering membrane 100 does not exceed the plastic deformation limit thereof.

[0098] As described above, the pump housing includes a covering membrane 100 defining a blood flow passage and a stent 200 supporting the expanded covering membrane 100. The impeller 410 is accommodated in the stent 200. During the switching of the pump body 4 from the natural expanded state to the working state, the stent 200 is configured not to participate in causing the elastic deformation and plastic deformation of the covering membrane. Alternatively, in the working state of the pump body 4, the stent 200 is configured not to participate in causing the elastic deformation and plastic deformation of the covering membrane 100.

[0099] The pump body 4 has an intervention configuration and a working configuration. In the intervention configuration of the pump body 4, the pump housing and the impeller are in a radially collapsed state, so that the pump body 4 intervenes in the vasculature of a subject or is delivered in the vasculature of a subject with a first outer diameter size. In the working configuration of the pump body 4, the pump housing and the impeller are in a radially expanded state, so that the pump body 4 pumps blood at a desired location with a second outer diameter size larger than the first outer diameter size.

[0100] The pump body 4 includes a radially collapsed state and a radially expanded state, and the pump housing is operable to switch between the radially collapsed state and the radially expanded state. Compared with the stress-free state, the covering membrane 100 does not plastically deform when the pump housing is in the radially expanded state.

[0101] By providing a collapsible pump housing, the pump housing has a smaller collapsed size and a larger expanded size, so as to meet the needs of reducing the pain of the subject during intervention / delivery and easy intervention, and providing large flow.

[0102] The design of the multi-mesh, especially the diamond mesh, of the stent 200 can achieve better folding, and the expansion is achieved by the memory characteristics of the nickel-titanium alloy. The blades are made of a flexible and elastic material, which stores energy when being collapsed, and the blades expand after the removal of external constraints.

[0103] The pump housing is folded by the external constraint, and is self-deployed after the constraint is removed. The external constraint is applied by a folding sheath (not shown) which is sleeved on the catheter 3. When the folding sheath moves forward outside the catheter 3, the pump housing is entirely accommodated in the folding sheath, and the pump housing is forced to fold. When the folding sheath moves backward, the radial constraint on the pump housing disappears, and the pump housing is self-deployed.

[0104] As described above, the folding of the pump housing is achieved by the radial constraint applied by the folding sheath, and the impeller contained in the pump housing is accommodated in the pump housing. Therefore, in essence, the folding process of the pump housing is that the folding sheath applies a radial constraint to the pump housing, and the pump housing is radially compressed to apply a radial constraint to the impeller.

[0105] That is, the pump housing is directly folded under the action of the folding sheath, and the impeller is directly folded under the action of the pump housing. As described above, the impeller has elasticity. Therefore, although in the folded state, the impeller has a tendency to always have a radial expansion due to the energy storage during folding, and the impeller will contact the inner wall of the pump housing and apply a counterforce to the pump housing.

[0106] After the constraint of the folding sheath is removed, the pump housing is deployed under the action of the memory characteristics of the pump housing, and the elastic covering film 100 is deployed, and the impeller is self-deployed under the action of the released energy storage. In the deployed state, the outer diameter of the impeller is smaller than the inner diameter of the pump housing.

[0107] In this way, the radial outer end of the impeller (that is, the blade tip) and the inner wall of the pump housing (specifically, the inner wall of the support 200) are kept apart, and the interval is the pump gap. The existence of the pump gap enables the impeller to rotate without obstruction and without bumping the wall.

[0108] In addition, from the perspective of fluid mechanics, it is desirable that the pump gap size is a small value and is maintained. In the present embodiment, the outer diameter of the impeller is slightly smaller than the inner diameter of the support 200 as the support, so that the pump gap is as small as possible while satisfying the condition that the impeller does not bump the wall during rotation. The main means to maintain the pump gap is the support strength provided by the support 200 and the anti-expansion deformation performance of the covering film 100. The support strength and the toughness of the covering film 100 can resist the action of the blood back pressure without excessive deformation, thereby maintaining the shape of the pump housing stable, and the pump gap is also stably maintained.

[0109] To ensure the toughness of the covering film 100, provide a more stable pump gap, and stabilize the pump efficiency, the critical point stress at which the covering film 100 plastically deforms should be greater than or equal to the force exerted by the blood back pressure on the covering film 100 due to the rotation of the impeller when the pump body is in the maximum working condition. The maximum working condition of the pump body corresponds to the maximum rotational speed of the impeller at the rated power. At this time, the pump flow corresponds to the maximum value, and the blood back pressure is also at the maximum value.

[0110] In this embodiment, the maximum value of the blood back pressure still does not exceed the critical point stress at which the covering 100 occurs plastic deformation limit, and further, in the working state of the impeller rotation, the covering 100 still does not exceed the plastic deformation limit, so as to reduce the change of the pump gap and stabilize the pump efficiency.

[0111] Further, in the process of switching the pump shell from the radially folded state to the naturally expanded state, the deformation of the covering 100 does not exceed the elastic deformation limit of the covering 100. In the process of switching the pump shell from the naturally expanded state to the working state, the deformation of the covering 100 does not exceed the elastic deformation limit of the covering 100.

[0112] The critical point stress at which the covering 100 occurs elastic deformation limit is greater than or equal to the force exerted by the blood back pressure on the covering 100 due to the rotation of the impeller when the pump body 4 is in the maximum working condition. In this way, when the impeller stops rotating or the fluid back pressure disappears, the covering 100 can still rely on elasticity to recover to the initial state, the pump efficiency is stable, and the service life is longer.

[0113] It should be clear that the deformation of the covering 100 in the present application refers to the length deformation of the covering 100 in the circumferential direction, which can include the flattening of the wrinkles, and can also include elastic deformation or even plastic deformation. When subjected to a radial force, the deformation of the covering 100 is manifested as an increase in the circumferential length (circumferential length).

[0114] In the process of switching the pump shell from the naturally expanded state to the working state, the diameter of the covering 100 increases by not more than 1mm, and the diameter increase rate is not more than 5%, further not more than 3%. In this way, the expansion deformation of the covering 100 under the action of the fluid back pressure does not exceed the plastic deformation limit of the covering 100, and cooperates with the impeller 410 to stably maintain the pump gap.

[0115] In the process of switching the pump shell from the naturally expanded state to the working state, the bracket is configured not to participate in causing the deformation of the covering 100. Alternatively, in the working state of the pump shell, the bracket is configured not to participate in causing the deformation of the covering 100. The deformation includes elastic deformation and plastic deformation. That is, in the process of switching the pump shell from the naturally expanded state to the working state, the bracket neither participates in causing the plastic deformation of the covering 100 nor participates in causing the elastic deformation of the covering 100.

[0116] In the natural expanded state, the inner diameter of the covering 100 is equal to or slightly larger than the outer diameter of the stent. For example, the diameter of the covering 100 is 1 to 1.1 times the outer diameter of the stent. Thus, in the entire process from the folded state to the expanded state, the covering 100 expanded by the radial expansion of the stent does not reach or exceed its original shape (original diameter). Therefore, the stent does not cause the circumferential stretching of the covering 100. It can be understood that the covering 100 does not have elastic deformation or plastic deformation in the natural expanded state, and the stent is configured not to cause the deformation of the covering 100.

[0117] In the present embodiment, the material of the covering 100 is TPU (thermoplastic polyurethane elastomer rubber) or PEBAX material or PTFE (polytetrafluoroethylene). Preferably, the covering 100 is made of a block polyether amide resin material such as PEBAX. The covering 100 has no loss of mechanical properties under repeated deformation, is fatigue-resistant, has good resilience and elastic recovery performance, and has precise dimensional stability. Furthermore, the deformation under the action of fluid back pressure does not exceed the plastic deformation limit or the elastic deformation limit, and the pump gap is stably maintained.

[0118] The distal end of the stent 200 is formed with a plurality of legs 204 in a substantially T-shaped structure, the leg 204 having a substantially vertical rod body 2041 and a leg end 2042. The outer wall of the distal end bearing chamber 6 is provided with a receiving groove, which includes a plurality of substantially axially extending axial grooves and a circumferential groove connected to the distal ends of the plurality of axial grooves. The plurality of rod bodies 2041 are respectively embedded in the corresponding axial grooves, and the plurality of leg ends 2042 are embedded in the circumferential groove. The outer wall of the distal end bearing chamber 6 is further provided with a hoop that tightly wraps and fixes the legs 204 to prevent them from being ejected from the receiving groove. The hoop can be a heat-shrinkable tube that is formed after being heated to bind the connecting legs 204 to the outer wall of the distal end bearing chamber 6, thereby achieving the anti-disengagement of the two.

[0119] The stent 200 has a support portion that contacts and supports the covering 100. In the natural expanded state, at least part of the support portion is in contact with the covering 100. In the working state, at least part of the support portion is separated from the covering 100.

[0120] Specifically, in the state that the impeller is rotating to drive the blood flow, under the action of the fluid back pressure, part of the folds of the covering 100 are flattened, or elastic deformation or plastic deformation occurs, and the inner diameter increases to separate from the support portion. However, under the toughness of the covering 100 itself, the deformation increase rate is limited, that is, even if elastic deformation or plastic deformation occurs to cause the circumferential elongation of the covering 100, the change in the elongation rate is less than 3%, the circumferential elongation change is small, and thus the spacing gap between the impeller and the covering 100 can still be maintained in the working state, and the pump efficiency is continuously and stably maintained.

[0121] The stent 200 comprises a stent proximal end 202 and a stent distal end 203 which are substantially conical, and a stent section 201 which is substantially cylindrical and is located between the stent proximal end 202 and the stent distal end 203. The stent section 201 with at least a partial axial length constitutes a support portion. The distal end of the covering 100 is sleeved on the stent section 201 and is contacted and supported by the stent section 201 to form a stable cylindrical pump housing. The distal end face of the covering 100 does not exceed the stent section 201.

[0122] During the transition of the pump housing from the radially collapsed state to the radially expanded state, the support portion and the covering 100 are allowed to move relatively, and the position of the covering 100 contacting the support portion such as the stent section 201 is allowed to change. The relative position of the stent 200 and the covering 100 does not change.

[0123] The support portion and the covering 100 are only in contact and support, without fixed connection, so that a certain degree of relative movement is formed between the support portion and the covering 100 during the expansion of the covering 100, thereby achieving the desired expansion of each other. Moreover, the support portion provides a circumferential support force to the covering 100 without providing a radial and circumferential relative motion constraint, allowing the covering 100 to move relatively radially or circumferentially with respect to the support portion, so that the position of the covering 100 contacting the support portion or the stent changes during the expansion.

[0124] In the blood flow state driven by the rotation of the impeller, the covering 100 mainly relies on the back pressure of the blood to increase in diameter, causing the covering 100 to separate from the stent 200 and not to contact, and the stent 200 loses the support to the covering 100 and thus does not participate in the deformation of the covering 100 at this time.

[0125] During the transition of the pump housing from the natural expanded state to the working state, the stent 200 increases in the radial direction at a lower rate than the covering 100. Specifically, the increase rate of the outer diameter of the stent 200 is lower than the increase rate of the inner diameter of the covering 100, or the increase size of the outer diameter of the stent 200 is smaller than the increase size of the inner diameter of the covering 100. During the transition of the pump housing from the natural expanded state to the working state, the increase rate of the outer diameter of the stent 200 is not more than 2%. Further, during the transition of the pump housing from the natural expanded state to the working state, the increase rate of the outer diameter of the stent 200 is not more than 1%.

[0126] In the feasible embodiment as shown in Figures 3-9 In order to make the stent not participate in causing the elastic or plastic deformation of the covering 100, and limit the deformation amount of the stent 200 in the working speed range of the impeller, the pump housing is further provided with an anti-expansion element 300 for limiting the expansion of the stent 200 in the radial direction. In the working state, the outer diameter of the stent 200 provided with the anti-expansion element 300 is smaller than the outer diameter in the case without the anti-expansion element 300.

[0127] In the present embodiment, the natural expanded state of the stent 200 is limited by the anti-expansion element 300. That is, radial expansion of the stent 200 causes the anti-expansion element 300 to be stretched. However, once the anti-expansion element 300 is stretched to a certain degree, the stent can no longer continue to expand, and the stent reaches a maximum diameter.

[0128] Fluid back pressure affects the radial expansion of the anti-expansion element 300 and the stent 200, but the radial expansion of the anti-expansion element 300 is limited, and the expansion of the anti-expansion element 300 is lower than the radial expansion of the covering 100. In the working state, the anti-expansion element 300 limits the radial expansion of at least part of the stent, and separates the stent from the covering 100. On the basis of the anti-expansion element 300, the anti-expansion element 300 limits the radial expansion of the stent 200 to be lower than the radial expansion of the covering 100.

[0129] The diameter of the anti-expansion element 300 is smaller than the diameter of the covering 100. The anti-expansion element 300 can be arranged inside the stent, or arranged outside the stent. The anti-expansion element 300 is arranged around the stent 200 inside the covering 100. Specifically, the anti-expansion element 300 is arranged around the stent segment 201.

[0130] The anti-expansion element 300 includes a hoop ring fixedly arranged outside the stent segment 201. The hoop ring can be welded or clamped to the outside of the stent segment 201. As shown in the embodiment, a plurality of hoop rings are arranged outside the stent segment 201. As shown in the embodiment, Figures 3-7 Figure 8 , Figure 9 The hoop ring is made of metal or other anti-expansion material, and has a stronger circumferential anti-expansion deformation capacity than the stent, and even stronger than the covering 100. Therefore, in the working state, the radial expansion rate of the stent is smaller under the action of the anti-expansion element 300, so as to separate from the covering 100 which further expands radially, and not in contact with each other.

[0131] It is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and many applications besides the examples provided herein will be apparent to those of skill in the art upon reading the above description. The scope of the technology should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for the purpose of the present disclosure. The omission of any aspect of the subject matter disclosed herein does not, therefore, create a patentable subject matter restriction upon the total present disclosure.​

Claims

1. A pump body of a catheter pump, comprising a pump housing, an impeller; the pump housing has a blood outlet and a blood inlet; the impeller is accommodated in the pump housing and is rotatable to pump blood from the blood inlet to the blood outlet; the impeller comprises a hub and blades arranged on the hub; the blades have blade tips, blade roots arranged on the hub, and reverse folds between the blade roots and the blade tips; the impeller has a natural unfolded state when not rotating and a working state when rotating at a maximum working speed; in the natural unfolded state, the blade roots extend obliquely in a radial direction along a first circumferential direction towards the reverse folds, and the reverse folds extend obliquely in a radial direction along a second circumferential direction towards the blade tips; the second circumferential direction is opposite to the first circumferential direction; the pump housing comprises a cover film defining a blood flow channel and a support frame supporting the unfolded cover film; the impeller is accommodated in the support frame; in the working state of the pump body, the deformation of the cover film does not exceed the elastic deformation limit thereof. In the process of switching the pump body from the natural unfolded state to the working state, the support frame is configured not to participate in causing elastic deformation and plastic deformation of the cover film; or in the working state of the pump body, the support frame is configured not to participate in causing elastic deformation and plastic deformation of the cover film. In the process of switching the pump housing from the natural unfolded state to the working state, the support frame has an increase in the radial direction that is lower than the increase in the radial direction of the cover film.

2. The pump body of claim 1, wherein, The pump housing is further provided with an anti-expansion element for limiting the expansion of the support frame in the radial direction; in the working state, the outer diameter of the support frame provided with the anti-expansion element is smaller than the outer diameter in the case where the anti-expansion element is not provided.

3. The pump body of claim 1, wherein, The anti-expansion element is arranged around the support frame in the cover film; preferably, the anti-expansion element comprises a hoop ring fixedly sleeved outside the support frame.

4. The pump body of claim 1, wherein, A pump gap is defined between the blade tips and the inner wall of the support frame; the gap width of the pump gap in the radial direction is less than 1.5 mm; in the process of switching the pump body from the natural unfolded state to the working state, the change in the gap width of the pump gap in the radial direction is less than 0.5 mm.

5. The pump body of claim 4, wherein, The blades comprise a first part between the blade root and the reverse fold, and a second part between the reverse fold and the blade tip; the radial length of the first part is greater than 0.5 times the radial length of the second part.

6. The pump body of claim 1, wherein, The radial length of the first part is greater than the radial length of the second part.

7. The pump body of claim 1, wherein, The cross-sectional area of the first part is more than 0.5 times the cross-sectional area of the second part.

8. The pump body of claim 7, wherein, The cross-sectional area of the first part is more than 0.8 times the cross-sectional area of the second part.

9. The pump body of claim 7, wherein, The maximum thickness of the second part is greater than 0.7 times the maximum thickness of the first part; wherein the blades have opposite concave pressure surfaces and convex suction surfaces; the thickness direction is the normal direction of the profile line of the concave pressure surface or the convex suction surface in the cross section.

10. The pump body of claim 7, wherein, The maximum thickness of the second part is greater than the maximum thickness of the first part.

11. The pump body of claim 7, wherein, ​ 12. The pump body of claim 11, wherein, ​ 13. The pump body of claim 1, wherein, In a cross section of the blade, a tangent line of the inflection portion passes through a center of the hub; the blade includes a first portion between the blade root and the inflection portion, and a second portion between the inflection portion and the blade tip; a length of the first portion in a direction perpendicular to the tangent line is more than 0.3 times a length of the second portion in the direction perpendicular to the tangent line.

14. The pump body of claim 13, wherein, The length of the first portion in the direction perpendicular to the tangent line is more than 0.5 times the length of the second portion in the direction perpendicular to the tangent line.

15. The pump body of claim 1, wherein, The blade includes a first portion between the blade root and the inflection portion, and a second portion between the inflection portion and the blade tip; the blade has a concave pressure surface and a convex suction surface facing away from each other; Any point on the inner concave flow surface or the outer convex flow surface of the first part is defined as a tangent line of the point, and the tangent line vector of the tangent line is away from the second part The tangent line of the point has a contact point with the outer contour line of the hub, and the radial vector of the center of the hub is towards the contact point The included angle β between the tangent line vector And the radial vector Is greater than 90 degrees and less than 180 degrees.

16. A conduit pump comprising: The pump body of any one of claims 1 to 15.

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