Centrifugal pump for biological fluids

Abstract

The centrifugal pump (1) for biological fluids, comprises: - one hollow body (2) defining a pumping chamber (3) provided with at least one inlet port (4) and with at least one outlet port (5) of a biological fluid; - one rotor element (6), housed within the pumping chamber (3) and controllable in rotation around an axis of rotation (X), the rotor element (6) comprising at least one impeller body (7), which defines an upper surface (7 a) supporting a plurality of blades (8) adapted to convey the biological fluid to the outlet port (5), wherein the blades (8) have a relevant thrust surface (18) adapted to interact, in use, with the biological fluid to push it towards the outlet port (5), where stheaid thrust surface (18) runs from the upper surface (7a), is arranged transversely to the upper surface (7a) itself and defines a relevant mating profile (18a) with the upper surface (7a) and a relevant upper profile (18b) opposite the mating profile (18a), wherein the upper profile (18b) protrudes from the mating profile (18a) of the corresponding blade (8) towards the blade (8) arranged upstream with respect to the way of rotation of said rotor element (6).

Description

[0001] CENTRIFUGAL PUMP FOR BIOLOGICAL FLUIDS

[0002] Technical Field

[0003] The present invention relates to a centrifugal pump for biological fluids, particularly blood.

[0004] Background Art

[0005] Centrifugal pumps used in the biomedical industry generally consist of an internally hollow body, provided with at least one blood inlet connector and one blood outlet connector, defining a pumping chamber within which a rotor element is housed provided with a plurality of blades adapted to convey, as a result of the rotation of the rotor element itself, the incoming blood towards the outlet connector.

[0006] Generally, the centrifugal pumps used for this purpose are of the type of magnetic levitation.

[0007] Specifically, the rotor element comprises a portion of magnetic material and outside the hollow body a stator element is arranged adapted to define at least one magnetic field for the lifting and the rotational control of the rotor element within the hollow body.

[0008] Additionally, the rotor element comprises an impeller body on which a plurality of blades is radially arranged.

[0009] The aforementioned blades are arranged on the upper portion of the rotor element facing the inlet connector, which has a truncated-conical conformation.

[0010] The inclined surface of the upper portion of the rotor element is intended to accompany the entry of the blood within the hollow body.

[0011] These centrifugal pumps of known type do have some drawbacks.

[0012] In particular, as a result of high RPM, the impeller body tends, in use, to rise upwards (helicopter effect). This is due to the fact that in pumps with either full magnetic levitation (i.e., without bearings supporting the rotor element in rotation) or partial magnetic levitation (i.e., provided with a lower bearing supporting the rotor element in rotation), the rotor element floats within its hollow body and, in use, gradually lifts as RPM increases.

[0013] Therefore, in order to prevent the rotor element, due to its uplift, from interfering, in use, with the upper wall of the hollow body, an adequate distance should be provided between them.

[0014] However, this expedient does have some drawbacks.

[0015] Specifically, an increase in the distance between the hollow body and the rotor element results in an increase in the overall volume (priming) of the pumping chamber which must be filled with the incoming blood from the patient.

[0016] In addition, as a result of its uplift, the rotor element moves away from the corresponding stator, so the electromagnetic control exerted by the latter loses its effectiveness.

[0017] In addition, in centrifugal pumps of known type, local turbulence frequently occurs at the blades resulting in mechanical damage to the cellular component of the blood (hemolysis, platelet damage, etc ...).

[0018] Some centrifugal pumps are known from WO 2024 / 023272 Al, US 2024 / 024658 Al, US 6 220 832 Bl, US 2011 / 318204 Al, US5458459A, US8398382B2, US6183220B1. The main aim of the present invention is to devise a centrifugal pump for biological fluids which allows the impeller body to reduce the upward thrust it receives in use.

[0019] Description of the Invention

[0020] Within this aim, one object of the present invention is to reduce the risk of damage to the cellular component of the blood as a result of local turbulence at the blades. Another object of the present invention is to devise a centrifugal pump for biological fluids which allows the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use as well as low-cost solution.

[0021] The aforementioned objects are achieved by this centrifugal pump for biological fluids according to claim 1.

[0022] Brief Description of the Drawings

[0023] Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a centrifugal pump for biological fluids, illustrated by way of an indicative, yet nonlimiting example, in the accompanying tables of drawings in which: Figure 1 is an axonometric view of a centrifugal pump according to the invention; Figure 2 is an exploded view of the centrifugal pump in Figure 1;

[0024] Figure 3 is a cross-sectional view of the centrifugal pump in Figure 1;

[0025] Figure 4 is an axonometric view of the impeller body of the centrifugal pump in Figure 1;

[0026] Figure 5 is a plan view from above of the impeller body in Figure 4;

[0027] Figure 6 is a cross-sectional view of the impeller body in Figure 4.

[0028] Embodiments of the Invention

[0029] With particular reference to these figures, reference numeral 1 globally denotes a centrifugal pump for biological fluids, particularly for blood.

[0030] The pump 1 comprises a hollow body 2 defining a pumping chamber 3 provided with at least one inlet port 4 and with at least one outlet port 5 of a biological fluid, e.g., blood.

[0031] Within the pumping chamber 3 is housed a rotor element 6, which is controllable in rotation around an axis of rotation X.

[0032] The way of rotation of the rotor element 6 is identified in Figure 5 with the arrow R.

[0033] The rotor element 6 comprises at least one impeller body 7, which defines an upper surface 7a supporting a plurality of blades 8 adapted to convey the biological fluid to the outlet port 5.

[0034] The upper surface 7a is arranged facing the inlet port 4 and faces, in use, upwards. In this description, the term “in use” relates to the position taken by the pump 1 during its use. Under ideal conditions of use, the axis of rotation X is arranged substantially vertical.

[0035] Appropriately, in use, the inlet port 4 is oriented upwards as shown in Figure 3. Preferably, the upper surface 7a has a substantially concave conformation.

[0036] In the embodiment shown in the figures, the hollow body 2 comprises at least one lower element 2a and at least one upper element 2b separated from each other and mutually coupled.

[0037] Additionally, the lower element 2a has a containment seat 10 adapted to house at least one portion of the impeller body 7, which defines a bottom wall 10a. A first sealing element 13 is placed between the upper element 2b and the lower element 2a.

[0038] Advantageously, the upper element 2b has at least one perimeter flange 11 mating the lower element 2a and at least one substantially dome-shaped body 12, which protrudes from the perimeter flange 11 and with which an outlet connector 14 defining the outlet port 5 is associated.

[0039] Preferably, the perimeter flange 11 defines a mating surface I la with the lower element 2a and is provided with an outlet connector 14, defining the outlet port 5, which is lifted with respect to the mating surface 1 la.

[0040] In the embodiment shown in the figures, the mating surface I la is substantially flat.

[0041] Preferably, the pump 1 is of the magnetic levitation type (full or partial). In this embodiment, the rotor element 6 comprises at least one magnetic portion 15 and is controllable in rotation around the axis of rotation X, contactless, by a stator element associable with the hollow body 2.

[0042] More particularly, the impeller body 7 is provided, in its lower part, with a housing seat 16 within which the magnetic portion 15 is inserted, which is inferiorly closed by a retaining element 17. A second sealing element 22 is placed between the magnetic portion 15 and the impeller body 7.

[0043] Appropriately, the blades 8 are arranged radially on the upper surface 7a. The blades 8 are therefore locked together with the impeller body 7 and are arranged in succession with each other.

[0044] The blades 8 have a relevant thrust surface 18 adapted to interact, in use, with the biological fluid to push it towards the outlet port 5. Thus, the thrust surface 18 is the surface that intercepts the biological fluid and that exerts a thrust thereon towards the outlet port 5.

[0045] Therefore, the thrust surface 18 is the surface of the blades 8 facing the same way of forward movement as the biological fluid.

[0046] The thrust surface 18 of each blade 8 runs from the upper surface 7a and is arranged transversely thereto.

[0047] The thrust surface 18 defines a relevant mating profile 18a with the upper surface 7a and a relevant upper profile 18b opposite the mating profile 18a. The upper profile 18b then bounds the thrust surface 18 superiorly.

[0048] According to the invention, the upper profile 18b protrudes from the mating profile 18a of the corresponding blade 8 towards the blade 8 arranged upstream with respect to the way of rotation of the rotor element 6.

[0049] The upper profile 18b of the thrust surface 18 of a blade 8 therefore protrudes towards the blade 8 arranged behind it, during its rotation around the axis of rotation X, and which is locked together with the same impeller body 7. In other words, the thrust surface 18 of the blades 8 is inclined with respect to the axis of rotation X in the opposite direction to the flow of biological fluid towards the outlet port 5.

[0050] More particularly, the thrust surface 18 extends seamlessly between the mating profile 18a and the upper profile 18b. In other words, the mating profile 18a and the upper profile 18b define the opposite edges of the thrust surface 18 arranged transversely to the upper surface 7a and adapted to intercept the biological fluid. Thus, between the mating profile 18a and the upper profile 18b there are no edges or other borders that interrupt the continuity of the thrust surface 18.

[0051] The thrust surface 18 is then punctually inclined with respect to a plane of reference 19 orthogonal to the axis of rotation X so as to define an obtuse angle therewith. In actual facts, a line, tangent to the thrust surface 18 if it is curvilinear or being part of the thrust surface 18 if it is flat, passes through each point of the thrust surface 18 and defines an obtuse angle with the plane of reference 19.

[0052] This orientation of the thrust surfaces 18 helps to decrease the upward thrust that is exerted, in use, on the impeller body 7.

[0053] In one embodiment, the thrust surface 18 is flat and defines an obtuse angle with the plane of reference 19 which is orthogonal to the axis of rotation X. Preferably, the angle formed by the thrust surface 18 with the plane of reference 19 is of between 91° and 120°.

[0054] In another embodiment, shown in the figures, the thrust surface 18 has a curvilinear development.

[0055] More particularly, the thrust surface 18 has curvilinear development with respect to a first axis of curvature Y, defining a first convexity.

[0056] The first axis of curvature Y is inclined with respect to a plane of reference 19 orthogonal to the axis of rotation X.

[0057] From the section in Figure 6 it can be appreciated that, in this case again, the thrust surface 18 is punctually inclined with respect to a plane of reference 19 orthogonal to the axis of rotation X.

[0058] This allows reducing the local turbulence at the blades 8 and, consequently, reducing the mechanical damage to the blood cellular component (hemolysis, platelet damage, etc.).

[0059] Preferably, the angle 0 formed by the tangent at a point to the upper profile 18b of the blades 8 around the first axis of curvature Y with the normal to the circumference around the axis of rotation X and passing through the same point of the upper profile 18b is of between 1° and 60°. Even more preferably, the angle 0 is of between 15° and 45°.

[0060] In one embodiment not shown in the figures, the thrust surface 18 has curvilinear development with respect to a second axis of curvature which is transverse to the first axis of curvature Y, thus defining a second convexity. This special conformation allows reducing the local turbulence at the blades 8 and, consequently, damage to the blood cellular component.

[0061] In the preferred embodiment shown in the figures, the blades 8 have a substantially constant thickness and have a rear surface 20 opposite and parallel to the thrust surface 18.

[0062] The rear surface 20 then faces the thrust surface 18 of the blade 8 arranged upstream with respect to the way of rotation of the impeller body 7.

[0063] Appropriately, the rear surface 20 is concave.

[0064] Between the thrust surface 18 and the rear surface 20 is placed a joining surface 23, which is bounded on one side by the upper profile 18b and on the other side by the corresponding profile of the rear surface 20. This joining surface 23, which does not therefore originate from the upper surface 7a, is therefore not part of the thrust surface 18.

[0065] More particularly, the rear surface 20 has at least a first concavity around the first axis of curvature Y. The rear surface 20 may also have a second concavity around the second axis of curvature.

[0066] Advantageously, the blades 8 define at least a relevant rear profile 18c, placed between the mating profile 18a and the upper profile 18b, having a substantially rectilinear development, so as to split the incoming blood entering the pumping chamber 3, and inclined with respect to an axis of reference A parallel to the axis of rotation X.

[0067] Appropriately, the blades 8 protrude with respect to the overall dimensions of the impeller body 7. In other words, the blades 8 have at least one joining profile 18d of the mating profile 18a with the upper profile 18b, where this joining profile 18d protrudes with respect to the overall dimensions of the impeller body 7. In the embodiment shown in the figures, the joining profile 18d has a curvilinear development.

[0068] In a preferred embodiment, the outer diameter of the blades 8 (measured at the radial end of the joining profile 18d) is larger than the outer diameter of the impeller body 7 by a percentage of between 20% and 60%. This feature, combined with the previously described conformation of the blades 8, provides an optimal balance between reducing the local turbulence at the blades, and consequently reducing damage to the blood cell component, and achieving a head comparable to the centrifugal pumps of known type.

[0069] Advantageously, the impeller body 7 comprises at least one through hole 21 arranged along the axis of rotation X and having a first opening facing the upper surface 7a and a second opening, opposite the first opening, facing the bottom wall 10a.

[0070] Specifically, the biological fluid entering the pumping chamber 3 through the inlet port 4 encounters the blades 8 and, while one part passes through the hole 21, the other part contacts the upper surface 7a and, as a result of the rotation of the blades 8, is conveyed to the outlet port 5.

[0071] The hole 21 thus allows the recirculation of some of the blood entering the pumping chamber 3, thus preventing blood stagnation phenomena.

[0072] Preferably, the blades 8 are arranged radially around the hole 21 and the rear profile 18c of each of them is arranged, with respect to the edge of the hole 21, at a different distance from the rear profile 18c of the adjacent blades 8.

[0073] In the preferred embodiment shown in the figures, the blades 8 are 12 in number.

[0074] It has, in practice, been ascertained that the described invention achieves the intended objects, and in particular, the fact is emphasized that the inclination of the thrust surfaces, directed in the opposite way to that of forward movement of the biological fluid, allows limiting the thrust which the impeller body receives upwards.

[0075] Again, the curvilinear development of the blades, the thrust surface of which interacting with the biological fluid to push it towards the outlet port is convex, allows reducing the phenomena of local turbulence and, therefore, mechanical damage to the blood cellular component.

Claims

CLAIMS1) Centrifugal pump (1) for biological fluids, comprising: at least one hollow body (2) defining a pumping chamber (3) provided with at least one inlet port (4) and with at least one outlet port (5) of a biological fluid; at least one rotor element (6), housed within said pumping chamber (3) and controllable in rotation around an axis of rotation (X), said rotor element (6) comprising at least one impeller body (7), which defines an upper surface (7 a) supporting a plurality of blades (8) adapted to convey the biological fluid to the outlet port (5), wherein said blades (8) have a relevant thrust surface (18) adapted to interact, in use, with the biological fluid to push it towards said outlet port (5), where said thrust surface (18) runs from said upper surface (7a), is arranged transversely to the upper surface (7a) itself and defines a relevant mating profile (18a) with said upper surface (7a) and a relevant upper profile (18b) opposite said mating profile (18a), characterized by the fact that said upper profile (18b) protrudes from the mating profile (18a) of the corresponding blade (8) towards the blade (8) arranged upstream with respect to the way of rotation of said rotor element (6).2) Pump (1) according to claim 1, characterized by the fact that said thrust surface (18) extends seamlessly between said mating profile (18a) and said upper profile (18b).3) Pump (1) according to claim 1 or 2, characterized by the fact that said thrust surface (18) of the blades (8) is inclined with respect to said axis of rotation (X) in the opposite direction to the flow of the biological fluid towards said outlet port (5).4) Pump (1) according to one or more of claims 1 to 3, characterized by the fact that said thrust surface (18) is punctually inclined with respect to a plane of reference (19) which is orthogonal to said axis of rotation so as to define an obtuse angle therewith.5) Pump (1) according to claim 4, characterized by the fact that said thrustsurface (18) is flat and defines an obtuse angle with said plane of reference (19).6) Pump (1) according to one or more of claims 1 to 4, characterized by the fact that said thrust surface (18) has a curvilinear development.7) Pump (1) according to claim 6, characterized by the fact that said thrust surface (18) has a curvilinear development with respect to a first axis of curvature (Y), defining a first convexity.8) Pump (1) according to claim 6 or 7, characterized by the fact that said thrust surface (18) has a curvilinear development with respect to a second axis of curvature which is transverse to said first axis of curvature (Y), defining a second convexity.9) Pump (1) according to claim 7 or 8, characterized by the fact that said first axis of curvature (Y) is parallel to or coincides with said axis of rotation (X).10) Pump (1) according to one or more of claims 7 to 9, characterized by the fact that said first axis of curvature (Y) is inclined with respect to a plane of reference (19) which is orthogonal to said axis of rotation (X) and by the fact that said thrust surface (18) is punctually inclined with respect to said plane of reference (19) so as to define an obtuse angle therewith.11) Pump (1) according to one or more of claims 7 to 10, characterized by the fact that the angle (0) formed by the tangent at a point to said upper profile (18b) around said first axis of curvature (Y) with the normal to the circumference around said axis of rotation (X) and passing through the same point of said upper profile (18b) is of between 1° and 60°.12) Pump (1) according to claim 11, characterized by the fact that said angle (0) is of between 15° and 45°.13) Pump (1) according to one or more of the preceding claims, characterized by the fact that said blades (8) have a substantially constant thickness and have a rear surface (20) opposite and parallel to said thrust surface (18), said rear surface being concave.14) Pump (1) according to one or more of the preceding claims, characterized by the fact that said blades (8) define a relevant rear profile (18c) positioned between said mating profile (18a) and said upper profile (18b) having a substantiallyrectilinear development, so as to split the blood entering said pumping chamber (3), and inclined with respect to an axis of reference (A) parallel to said axis of rotation (X).15) Pump (1) according to one or more of the preceding claims, characterized by the fact that said blades (8) protrude with respect to the overall dimensions of said impeller body (7).16) Pump (1) according to claim 15, characterized by the fact that the outer diameter of said blades (8) is larger than the outer diameter of said impeller body (7) by a percentage of between 20% and 60%.17) Pump (1) according to one or more of the preceding claims, characterized by the fact that said hollow body (2) has a bottom wall (10a), by the fact that said impeller body (7) comprises at least one through hole (21) arranged along said axis of rotation (X) and having a first opening which faces said upper surface (7a) and a second opening, opposite said first opening, which faces said bottom wall (10a), by the fact that said blades (8) are arranged radially around said hole (21) and by the fact that the rear profile (18c) of each of said blades (8) is arranged, with respect to the edge of said hole (21), at a different distance from the rear profile (18c) of the adjacent blades (8).18) Pump (1) according to one or more of the preceding claims, characterized by the fact that said rotor element (6) comprises at least one magnetic portion (15), said rotor element (6) being controllable in rotation around said axis of rotation (X), contactless, by a stator element associated with said hollow body (2).

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