Pump unit for centrifugal pump and centrifugal pump

Abstract

To provide a pump unit for a centrifugal pump.SOLUTION: The centrifugal pump includes a pump unit, and a stator extending in an axial direction from a first axial end to a second axial end. A cup-shaped recess into which the pump unit is capable of being inserted is provided at the first axial end. The pump unit comprises a pump housing and a rotor. Vanes of the rotor are arranged around a central inlet area of the rotor. The rotor comprises at least one relief opening to generate a recirculation flow directed from a back side of the rotor facing away from the inlet in a direction of the central inlet area of the rotor. The rotor further has a separating element arranged in the central inlet area. The separating element is configured to redirect the recirculation flow in a radial direction perpendicular to the axial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a pump unit for a centrifugal pump according to the preamble of the independent claim.The invention further relates to a centrifugal pump comprising such a pump unit. [Background technology]

[0002] A centrifugal pump is known that includes a pump unit and a stator designed as a drive unit for the rotor of the pump unit, where the rotor of the pump unit forms the centrifugal wheel of the centrifugal pump. The rotor can be magnetically supported without contact and can be driven without contact by the stator in the pump unit to rotate about its axial center. Such a centrifugal pump is, for example, commercially available from the applicant under the product name Levitronix® BPS Pump.

[0003] The stator and rotor form an electromagnetic rotary drive. For example, in the Levitronix® BPS pump, the electromagnetic rotary drive is designed according to the bearingless motor principle. The term bearingless motor refers to an electromagnetic rotary drive in which the rotor is fully magnetically supported relative to the stator, without a separate magnetic bearing. For this purpose, the stator is designed as a bearing-drive stator, serving both as the stator of the electric drive and the stator of the magnetic bearing. The stator's electrical windings can generate a rotating magnetic field, which, on the one hand, exerts a torque on the rotor, which causes it to rotate about the desired axis of rotation defined by the axial direction, and, on the other hand, exerts an adjustable lateral force on the rotor, thereby allowing the rotor's radial position to be actively controlled or adjusted. Thus, three degrees of freedom of the rotor can be actively adjusted: rotor rotation and rotor radial position (two degrees of freedom). With respect to three further degrees of freedom, namely the rotor's axial position and its tilt relative to a radial plane perpendicular to the desired axis of rotation (two degrees of freedom), the rotor is passively magnetically supported or stabilized by reluctance forces, i.e., the rotor cannot be controlled. The absence of a separate magnetic bearing with a complete magnetic bearing for the rotor is the characteristic that gives bearingless motors their name. With a bearing-drive stator, the bearing function cannot be separated from the drive function.

[0004] Of course, other centrifugal pump designs are known in which the rotor is magnetically supported without contact, for example, by providing a separate magnetic bearing on the rotor, thereby separating the magnetic bearing function from the drive function. For example, a separate coil is provided for this purpose, which provides only a bearing force on the rotor but does not contribute to the rotor drive. For example, such a centrifugal pump is disclosed in WO 2022 / 004144.

[0005] Centrifugal pumps with contactless, magnetically supported and driven rotors, for example rotors designed and operated according to the principle of bearingless motors, have proven themselves in many applications. Due to the absence of mechanical bearings, such centrifugal pumps are suitable for applications in which very delicate substances are conveyed, such as blood pumps, or where very high demands are made on purity, for example in the semiconductor, pharmaceutical or biotechnology industries, or where abrasive or aggressive substances are conveyed, which would very quickly destroy mechanical bearings, such as pumps for slurries, sulfuric acid, phosphoric acid or other chemicals in the semiconductor industry.

[0006] Figure 1 shows a diagram of a centrifugal pump 200' known from the state of the art, designed according to the principle of a bearingless motor. This is, for example, a Levitronix® BPS pump. For better understanding, in Figure 1 a segment has been cut away to make the interior of the centrifugal pump 200' visible. The centrifugal pump 200' comprises a stator 100' and a pump unit 1'.

[0007] A pump unit 1' suitable for this type of centrifugal pump 200' is disclosed, for example, in EP 2 273 124. Figure 2 shows such a pump unit 1' in cross section, the cross section being along the axial direction A.

[0008] 1 and 2 are devices from the state of the art, the reference signs are here marked with inverted commas or dashes, respectively. The centrifugal pump is designated overall with the reference sign 200'.

[0009] A rotor 10' forming a centrifugal wheel or impeller, by means of which the fluid is conveyed, is arranged in the pump unit 1'. The stator 100' has a stator housing 130' and extends in the axial direction A from a first axial end 110' to a second axial end 120'. A cup-shaped recess 121' is provided in the first axial end 110', into which the pump unit 1' can be inserted. Together with the rotor 10', the stator 100' forms an electromagnetic rotary drive for rotating the rotor 10' about the axial direction A. The stator 100' is designed for a contactless magnetic bearing of the rotor 10' according to the bearingless motor principle. For this purpose, the stator 100' is designed as a bearing-drive stator, by means of which the rotor 10' can be magnetically driven to rotate about the axial direction A without contact and can be magnetically supported without contact relative to the stator 100', the rotor 10' being passively magnetically stabilized in the axial direction A and actively magnetically supported in a radial plane perpendicular to the axial direction A, which plane is indicated by the line E in FIG. 1.

[0010] The electromagnetic rotary drive device, including the stator 100' and the rotor 10', is designed as a so-called temple motor. The stator 100' includes multiple coil cores 125', here eight coil cores 125'. Each of the eight coil cores 125' includes a longitudinal leg 126' extending from a first end, which is located at the bottom in FIG. 1, in the axial direction A to a second end, and a transverse leg 127' located at the second end of the longitudinal leg 126' in a radial plane E. Each transverse leg 127' extends radially from the associated longitudinal leg 126' toward the rotor 10' and is bounded by a radially inner end face. The coil cores 126' are circumferentially arranged around the cup-shaped recess 121', and thus around the rotor 10', such that the rotor 10' is arranged between the radially inner end faces of the transverse legs 127' of the coil cores 126'.

[0011] The first ends of all of the longitudinal legs 126' are connected to one another by a back iron 122' for conducting magnetic flux. At least one concentrated winding 160', 161' is provided on each longitudinal leg 126' and surrounds the respective longitudinal leg 126'. Many variations are known regarding the number and arrangement of concentrated windings 160', 161' and will not be described in further detail here. For example, there are such windings 160' wound around exactly one longitudinal leg 126' and such windings 161' arranged around exactly two longitudinal legs 126'.

[0012] The plurality of longitudinal legs 126' extending in the axial direction A and reminiscent of temple columns give the temple motor its name.

[0013] The pump unit 1′ known from EP 2 273 124 A1 (FIG. 2) comprises a pump housing 2′ having an inlet 21′ and an outlet 22′ for the fluid to be conveyed, and a rotor 10′ arranged in the pump housing 2′ for conveying the fluid, the rotor being capable of being rotated about an axial direction A. The rotor 10′ comprises a magnetically effective core 101′ which magnetically cooperates with a stator 100′ to generate a torque and to generate a magnetic bearing force. For example, the magnetically effective core 101′ is a permanent magnetic ring or a permanent magnetic disk.

[0014] Such a design is also possible in which the magnetically effective core 101' is designed in a manner that does not include a permanent magnet, i.e., without a permanent magnet. In this case, the rotor 10' is designed, for example, as a reluctance rotor. Furthermore, the magnetically effective core 101' of the rotor 10' is made, for example, of a soft magnetic material. Suitable soft magnetic materials for the magnetically effective core 101' are, for example, ferromagnetic or ferrimagnetic materials, i.e., in particular, iron, nickel-iron, cobalt-iron, silicon-iron, and mu-metal.

[0015] Additionally, designs are possible in which the magnetically effective core 101' of rotor 10' includes both ferromagnetic and permanent magnetic materials. For example, permanent magnets can be positioned or inserted within a ferromagnetic substrate. Such designs are advantageous, for example, when it is desired to reduce the cost of large rotors by conserving permanent magnetic material.

[0016] Typically, the magnetically effective core 101' is completely encased in plastic. In other designs, the magnetically effective core 101' is completely surrounded by a cladding 102' made of a ceramic or metallic material, such as stainless steel or titanium or tantalum.

[0017] Additionally, the rotor 10' includes a plurality of vanes 103' for conveying fluid from the inlet 21' to the outlet 22'.

[0018] The inlet 21' of the pump housing 2' is arranged and designed so that the fluid to be conveyed flows in the axial direction A towards the rotor 10'. The outlet 22' extends parallel to the radial plane E, i.e., substantially perpendicular to the inlet 21'.

[0019] The pump housing 2' includes a cylindrical cup 31' for receiving the rotor 10'. The cup 31' is inserted into a recess 121' in the stator housing 130' so that the rotor 10', or more precisely the magnetically effective core 101' of the rotor 10', is located between the lateral legs 127' of the coil core 126'.

[0020] In many applications, such as those in the semiconductor industry, the pump unit 1', except for the magnetically effective core 101', is made of plastic, such as perfluoroalkoxy polymer (PFA) or polytetrafluoroethylene (PTFE), because these are plastics with particularly high chemical resistance. These plastics are essentially inert materials that cannot be attacked even by highly chemically aggressive substances, such as those frequently used in the semiconductor industry. In addition, PFA and PTFE are very pure plastics because they usually contain no additives and their molecular complexes are at least nearly inert. PFA is often preferred because it can be processed in injection molding processes.

[0021] In a centrifugal pump 200′ in which the conveyed fluid is redirected from the axial direction A to the radial direction, the rotor 10′ is subjected to a strong load in the axial direction A. The axial thrust acting on the rotor is primarily caused by a pressure difference across the rotor 10′. While the suction pressure is substantially dominant on the side of the rotor 10′ facing the inlet 21′, a higher pressure exists on the back side of the rotor 10′ because the back side of the rotor is connected to the outlet 22′ where the conveying pressure is substantially dominant. The resulting axial thrust is particularly problematic in a centrifugal pump 200′ having a non-contact magnetically supported rotor 10′. To avoid having to fully support the axial thrust with the axial magnetic bearing or to stabilize the rotor 10′, various means are known, such as a relief opening 104′ that extends through the entire rotor 10′ in the axial direction A, thus forming a flow connection between the front side of the rotor 10′ facing the inlet 21′ and the back side of the rotor 10′, thereby providing pressure relief for the rotor 10′ in the axial direction A.

[0022] For example, EP 2273124 proposes dividing the vanes 103' of the rotor 10' into two centrifugal wheels by a separation element 7' aligned perpendicular to the axial direction A: a first centrifugal wheel 105' for generating a main flow HF' from the inlet 21' to the outlet 22', and a second centrifugal wheel 106' for generating a recirculation flow RF' guided from the rear side of the rotor 10' through a relief opening 104'. In FIG. 2, the main flow HF' is indicated by a solid arrow HF', while the recirculation flow RF' is indicated by a dashed arrow RF'. Each vane 103' is divided by the separation element 7' into a first vane 107' and a second vane 108'. The entire first vane 107' forms the first centrifugal wheel 105', and the entire second vane 108' forms the second centrifugal wheel 108'. The first vanes 107' are positioned so that the central inlet region 25' of the rotor 10' is free of the vanes 103'. The vanes 103' are positioned around this central inlet region 25'.

[0023] The separation element 7', which separates the two centrifugal wheels 105' and 106' from each other, redirects the recirculation flow RF' from the axial direction A to the radial direction and at least partially separates the recirculation flow RF' from the main flow HF' so that they cannot directly mix with each other at the outlet of the relief opening 104'. In this case, the separation element 7' extends radially within the vanes 103', i.e., radially, the separation element 7' overlaps with the vanes 103'.

[0024] Although this design with the separating element 7' has proven itself in practice, the manufacture of such a rotor 10' is very complex and sophisticated. For example, the rotor 10' must be assembled from several individual parts. For the separating element 7', recesses must be provided in the vanes 103' so that the separating element 7' can be inserted between the vanes 103'.

[0025] For example, if the pump unit 1' is made of plastic, the individual components must be connected to each other in a reliable and stable manner. This is done, for example, by a welding process. In addition to time and cost factors, any welding process carries the risk of leaks occurring at the welded connections, thereby compromising the operational reliability of the entire centrifugal pump 200'. There is also the risk that cracks or small gaps may develop at the welded connections. Contaminants may accumulate there and break off under operating conditions, contaminating the transported fluid. In many applications, for example in the semiconductor industry, even the smallest impurities can have dramatic consequences, for example, rendering the final product unusable.

[0026] To ensure that the components of the rotor 10' that come into contact with the fluid—particularly the axial relief opening 104' and the lower, inwardly located edge of the separating element 7'—can perform their intended function, a very high level of precision and dimensional accuracy is required. In most cases, the components are manufactured using manufacturing processes (e.g., injection molding) in which deviations from a predetermined target geometry are unavoidable. This leads to the fact that protruding bulges or other deviations from the target geometry disrupt the fluid flow and thus significantly impair functionality. This means that the components must be reworked before assembly, i.e., in their individual parts. If the components of the rotor 10' have already been assembled, reworking is no longer possible because the areas of the rotor 10' that require reworking are no longer sufficiently accessible for the corresponding reworking tools. This means, on the one hand, that the rotor 10' known from the state of the art must be assembled from several individual parts. On the other hand, it means that, apart from the assembly of the rotor 10', additional work steps are required for the rotor 10' to perform its intended function. [Prior art documents] [Patent documents]

[0027] [Patent Document 1] International Publication No. 2022 / 004144 [Patent Document 2] European Patent Application Publication No. 2273124 [Patent Document 3] European Patent No. 2273124 Summary of the Invention

[0028] Starting from this state of the art, it is therefore an object of the present invention to propose a pump unit for a centrifugal pump having a rotor that can be magnetically levitated without contact, which pump unit is particularly simple in terms of its manufacture and is characterized by a high degree of operational reliability, as well as a centrifugal pump having such a pump unit.

[0029] The subject matter of the invention which meets this object is characterized by the features of the independent patent claims.

[0030] Therefore, according to the present invention, a pump unit for a centrifugal pump is proposed, the centrifugal pump comprising a pump unit and a stator extending axially from a first axial end to a second axial end, a cup-shaped recess being provided at the first axial end, the pump unit being insertable into the cup-shaped recess, the pump unit having a pump housing with an inlet and an outlet for the fluid to be conveyed, and a rotor arranged in the pump housing and having a plurality of vanes for conveying the fluid, the rotor being rotated about the axial direction, the pump unit being designed for contactless magnetic levitation and contactless magnetic drive of the rotor by the stator, the vanes of the rotor being arranged around a central inlet region of the rotor, the rotor having at least one relief opening for generating a recirculation flow directed from a back side of the rotor facing opposite the inlet towards the central inlet region of the rotor, the rotor further comprising a separation element arranged in the central inlet region, the separation element redirecting the recirculation flow in a radial direction perpendicular to the axial direction. The plurality of vanes of the rotor, the separating element and the at least one relief opening are designed as an integral unit.

[0031] Due to the integrated design of the rotor vane, the separating element, and the at least one relief opening, the rotor no longer needs to be assembled from several components and can be manufactured as a monolithic device in a very simple manner. In addition, no connections between the individual components, for example by gluing, screwing, or welding, are required, which reduces the construction effort on the one hand and increases operational safety, since welded connections that could lead to leaks during operation are no longer necessary.

[0032] For example, the integral unit including the vane, the separating element, and at least one relief opening can be designed as a one-piece injection-molded part. Manufacturing using an injection molding process allows for particularly cost-effective and economical production of the rotor. Additionally, the rotor is necessarily designed in this case so that it can be demolded, i.e., removed from the tool after the injection molding process.

[0033] According to a preferred embodiment, there is exactly one relief opening connecting the central inlet area of ​​the rotor to the rear side of the rotor, which is then centrally located within the rotor.

[0034] In other embodiments of the pump unit according to the invention, several relief openings are provided, arranged around the central axis of the rotor, each relief opening connecting the central inlet area of ​​the rotor to the rear side of the rotor. For example, the relief openings are arranged on a circle, the center of which is on the central axis of the rotor. In these embodiments, a relief opening surrounding the central axis can also be provided in the center of the rotor. In this case, the other relief openings are arranged around the central relief opening.

[0035] Preferably, the rotor comprises a ring-shaped or disc-shaped magnetically effective core and a cladding completely surrounding the magnetically effective core, the cladding being a component of an integral unit comprising the vanes and the separating elements, in this embodiment the cladding, the vanes, the separating elements and all the relief openings are designed as a monolithic component.

[0036] In a preferred embodiment, the separation element is designed and positioned so that at least one relief opening is partially visible from the inlet. This means that the separation element does not completely cover the relief opening or openings. This has the advantage that the relief opening(s) are accessible from the pump inlet, which allows, for example, subsequent machining of the relief opening(s), for example chip removal.

[0037] According to a preferred embodiment, the separation element comprises a separation plate and a mounting web, the separation plate having a maximum radial outer diameter that is at most as large as the diameter of the central inlet area of ​​the rotor, the mounting web being designed to fix the separation plate. With a design with mounting webs, it is no longer necessary to attach the separation element to the vanes, although this is still possible, thereby reducing the construction effort.

[0038] Preferably, the separator plate is designed so that its maximum outer diameter is smaller than the diameter of the central inlet region of the rotor, and in this case, the separator plate is radially dimensioned so that it can be positioned between the vanes without contacting them.

[0039] In a further preferred embodiment, each mounting web extends from the separator plate to the cladding, and a radial opening for the recirculation flow is provided between each adjacent mounting web. In this way, the separator plate is fixed to the cladding, and the recirculation flow can flow radially from between the mounting webs. Here, the radial openings between the mounting webs are preferably arranged so that, when viewed radially, they are aligned with the gaps between two adjacent vanes, so that the recirculation flow can flow unimpeded between the two adjacent vanes.

[0040] In a preferred embodiment, each attachment web extends axially from the underside of the separator plate to the cladding, and in this embodiment, the attachment webs are preferably completely covered by the separator plate so that the separation webs are not visible from the inlet.

[0041] According to another preferred embodiment, each attachment web is arranged on the outer edge of the separator plate and extends radially from the outer edge. In this embodiment of the attachment webs as radial struts, the attachment webs are visible from the inlet. When viewed from the inlet of the pump housing, the separator element appears star-shaped.

[0042] In embodiments where the attachment webs are located on the outer edge of the separator plate, the attachment webs are preferably located equidistantly on the outer edge of the separator plate.

[0043] In a preferred variation of this embodiment, each of the attachment webs extends radially to one of the vanes, in which case each of the attachment webs is in direct physical contact with one of the vanes. This embodiment also has the advantage that the radial openings for recirculation flow located between the attachment webs merge into the radial openings between adjacent vanes, thereby avoiding or at least dramatically reducing turbulence, among other things.

[0044] Furthermore, particularly in these embodiments, it is preferred that the number of attachment webs equal the number of vanes, thus creating a continuous channel for recirculation flow.

[0045] Furthermore, the invention proposes a centrifugal pump for conveying a fluid, which comprises a pump unit designed according to any one of the preceding claims and having a cylindrical cup for receiving a rotor and a stator extending axially from a first axial end to a second axial end, a cup-shaped recess being provided at the first axial end, the cylindrical cup of the pump unit being insertable into the cup-shaped recess, the stator forming together with the rotor an electromagnetic rotary drive for rotating the rotor about its axial center, the stator being designed as a bearing-drive stator, in which the rotor can be magnetically driven and magnetically levitated without contact relative to the stator, and the rotor being passively magnetically stabilized in the axial direction and actively magnetically levitated in a radial plane perpendicular to the axial direction.

[0046] Particularly preferably, the electromagnetic rotary drive is designed as a temple motor, and the stator has a plurality of coil cores, each of which has a longitudinal leg extending axially from a first end to a second end and a transverse leg extending radially from the longitudinal leg and arranged in a radial plane at the second end of the longitudinal leg, the coil cores being arranged circumferentially around the rotor, so that the rotor is arranged between the transverse legs of the coil cores, and at least one concentrated winding is provided on each longitudinal leg, which winding surrounds the respective longitudinal leg.

[0047] Further advantageous measures and embodiments of the invention are evident from the dependent claims.

[0048] The invention will now be explained in more detail with reference to embodiments and with reference to the drawings, in which: FIG. [Brief explanation of the drawings]

[0049] [Figure 1] 1 is a perspective view, partly in section, of a centrifugal pump according to the state of the art; [Figure 2]1 is a cross-sectional view of a pump unit according to the state of the art; [Figure 3] 1 is a cross-sectional view of an embodiment of a pump unit according to the present invention; [Figure 4] 4 is a perspective view, partly in section, of the rotor of the pump unit of FIG. 3; [Figure 5] 5 is a cross-sectional view of the rotor taken along the line VV in FIG. 4. [Figure 6] FIG. 2 is a cross-sectional view of a first variant of the rotor. [Figure 7] 7 is a perspective view, partly in section, of a first variant of the rotor according to FIG. 6; FIG. [Figure 8] FIG. 8 is a cross-sectional view of a first variant of the rotor in a cross section along the section line VIII-VIII of FIG. 7; [Figure 9] FIG. 10 is a cross-sectional view of a second variant of the rotor. [Figure 9A] FIG. 10 is a plan view from the inlet of the pump housing, showing a second variant of the rotor. [Figure 10] 10 is a perspective view, partly in section, of a second variant of the rotor according to FIG. 9; [Figure 11] 11 is a cross-sectional view of a second variant of the rotor in section along the section line XI-XI of FIG. 10; [Figure 12] FIG. 10 is a plan view from the inlet of the pump housing, showing a third variant of the rotor. [Figure 13] 13 is a perspective view, partly in section, of a third variant of the rotor of FIG. 12; FIG. [Figure 14] 14 is a cross-sectional view of a third variant of the rotor taken along the section line XIV-XIV in FIG. 13; [Figure 15] 1 is a schematic cross-sectional view of one embodiment of a centrifugal pump according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0050] As already explained above, Fig. 1 shows a centrifugal pump 200' having a contactless magnetically supported, contactless magnetically driven rotor 10' known from the state of the art. Fig. 2 shows in a cross-sectional view a pump unit 1' known from the state of the art and suitable for example for the centrifugal pump 200' according to Fig. 1.

[0051] FIG. 3 shows an embodiment of a pump unit according to the invention in a cross-sectional view corresponding to FIG. 2 and designated in its entirety by the reference number 1.

[0052] The pump unit 1 is designed for a centrifugal pump 200 (see FIG. 15) for conveying a fluid and comprises a pump housing 2 having an inlet 21 and an outlet 22 for the fluid. A rotor 10 for conveying the fluid is arranged in the pump housing 2, which rotor forms the centrifugal wheel or impeller of the pump unit 1 and thus of the centrifugal pump 200. The rotor 10 can be rotated about a desired axis of rotation that defines an axial direction A. This desired axis of rotation is the central axis M of the rotor 10.

[0053] In the axial direction A, the rotor 10 extends from a front side facing the inlet to a back side facing away from the inlet 21 .

[0054] For better understanding, Figure 4 shows the rotor 10 of the pump unit 1 in a perspective view, with a sector cut out of the rotor 10. Furthermore, Figure 5 shows the rotor 10 in a cross-section, taken along the cutting line VV in Figure 4.

[0055] The direction perpendicular to the axial direction A is designated as the radial direction. In the following, the term "axial" is used in its generally accepted sense of "axially" or "with respect to the axial direction." The term "radial" is used in its generally accepted sense of "radially" or "with respect to the radial direction."

[0056] The pump unit 1 is designed for contactless magnetic levitation and contactless magnetic drive of the rotor 10. This can be realized in a similar manner to that described above with reference to FIGS. 1 and 2. Therefore, the pump unit 1 according to the present invention can be designed in a similar manner to the pump unit 1' of FIG. 1 or 2 with respect to magnetic levitation and magnetic drive. For this purpose, the rotor 10 of the pump unit 1 comprises a magnetically effective core 101 surrounded by a sheath 102, which may be designed, for example, as a permanent magnetic ring or disk. The sheath 102 is preferably designed as a plastic sheath. The sheath 102 is made, for example, of PTFE or PFA. The magnetically effective core 101 is enclosed within the sheath 102, i.e., the sheath 102 completely, preferably airtightly, surrounds the magnetically effective core 101. As a result, the magnetically effective core 101 is protected from fluids. The sheath 102 may be manufactured, for example, by spraying plastic around the magnetically effective core 101.

[0057] The magnetically effective core 101 of the rotor 10 is the component of the rotor 10 that magnetically cooperates with the stator 100 to generate torque and generate a magnetic levitation force.

[0058] Furthermore, the rotor 10 comprises a plurality of vanes 103 for conveying the fluid from the inlet 21 to the outlet 22. The vanes 103 are arranged on the cladding 102 of the magnetically effective core 101. The vanes 103 are preferably made of plastic and are preferably designed integrally with the cladding 102. Of course, it is also possible to manufacture the individual vanes 103 or the entire vane 103 in a separate manufacturing process and then connect them to the cladding 102 of the magnetically effective core 101, for example by means of a welding process.

[0059] The impeller with the vanes 103 formed by the rotor 10 is preferably designed as a radial impeller, to which the fluid approaches from the inlet 21 in the axial direction A and then redirects the fluid radially.

[0060] The pump housing 2 comprises a cover part 4 and a bottom part 3, which are sealingly connected to one another, but this is not shown in more detail in Figure 3 as it is not necessary for an understanding of the invention. The bottom part 3 comprises a cylindrical cup 31 for receiving the rotor 10. The cup 31 is preferably designed and arranged so that it can be inserted into a cup-shaped recess in the stator 100, as shown diagrammatically in Figure 15.

[0061] The stator 100 (FIG. 15) has a substantially cylindrically designed stator housing (not shown in FIG. 15) that extends in the axial direction A from the first axial end 110 to the second axial end 120. A cup-shaped recess is arranged at the first axial end 110 of the stator 100, preferably centrally in the end face that forms the first axial end 110 of the stator 100. The design of the stator housing with the cup-shaped recess can be realized in particular in a manner similar to that described with reference to FIG. 1 for the stator housing 130′ and the cup-shaped recess 121′. Thus, the cup 31 is arranged and designed so that it can be inserted into the recess 121′ (FIG. 1) at the first axial end 110′ of the stator 100′, and the magnetically effective core 101 is arranged between the lateral legs 127′ of the coil core 125′.

[0062] As can be seen in Fig. 3, above the cup 31 there is a pump chamber 23, which is bounded by the pump housing 2 and in which the vanes 103 of the rotor 10 are arranged. The pump chamber 23 is designed at least substantially cylindrical, the diameter of the pump chamber 23 being greater than the inner diameter of the cup 31. Consequently, the pump housing 2 has a flange-like projection 24, which bounds the pump chamber 23 downwards with respect to the axial direction A according to the figure.

[0063] The inlet 21 is centrally located within the cover part 4 of the pump housing 2 so that fluid can flow in the axial direction A towards the rotor 10 .

[0064] Each vane 103 extends from a leading edge 109 disposed radially inward to a trailing edge 110 disposed radially outward. In the embodiment described herein, the vanes 103 are designed, by way of example, to extend radially linearly from the leading edge 109 to the trailing edge 110 and to have a constant height throughout their extension. Here, height refers to the extension of the vane 103 in the axial direction A. As noted above, this design should be understood as an example only. In other embodiments, the vanes 103 are designed, for example, to be curved relative to the radial direction and / or to have a height in the axial direction A that varies from the leading edge 109 to the trailing edge 110. For example, an embodiment in which the vanes 103 have a greater height at their leading edges 109 than at their trailing edges 110 is shown in FIG. 15 .

[0065] Furthermore, a ring-shaped cover plate 8 is provided, which is arranged on the upper edge of the vane 103 facing the inlet 21. The cover plate 8 covers all of the vanes 103. In the radial direction, the ring-shaped cover plate 8 extends from the leading edge 109 of the vane 103 to the trailing edge 110 of the vane 103. The cover plate 8 can be designed integrally with the vane 103.

[0066] As can be seen particularly clearly in Figures 4 and 5, the vanes 103 of the rotor 10 are arranged around a central inlet region 25 that is devoid of vanes 103. The leading edges 109 of the vanes 103 lie on a line, here a circular line, that has a distance from the central axis M of the rotor 10 that is different from zero. A diameter D1 of the central inlet region 25 is determined by the distance of the leading edges 109 of the vanes 103 from the central axis M of the rotor 10. This diameter D1 of the central inlet region 25 is equal to twice the distance of the leading edges 109 of the vanes 103 from the central axis M of the rotor 10. In the embodiment described herein, the diameter D1 of the central inlet region 25 is the same size as the inner diameter of the ring-shaped cover plate 8.

[0067] If the leading edge 109 of the vane does not extend parallel to the axial direction A, for example, but is inclined relative to the axial direction A, the diameter D1 of the central inlet region 25 is determined by the distance of the leading edge 109 at the upper edge of the vane 103 facing the inlet 21.

[0068] The rotor 10 further comprises at least one relief opening 104 for generating a recirculation flow RF directed from the back side of the rotor 10 facing away from the inlet 21 toward the central inlet region 25. In the embodiment shown in FIGS. 3 to 5, exactly one relief opening 104 is provided, designed as a circular cylinder and extending in the axial direction A. The relief opening 104 is arranged in the center of the rotor 10 so that the axis of the relief opening 104 coincides with the central axis M of the rotor 10. The relief opening 104 extends in the axial direction A from the central inlet region 25 through the rotor 10 to the back side of the rotor 10. The rotor 10 further comprises a separation element 7, which is arranged in the central inlet region 25 of the rotor 10 and redirects the recirculation flow RF flowing from the back side of the rotor 10 through the relief opening 104 from the axial direction A to a radial direction.

[0069] Preferably, the separating element 7 comprises a separating plate 71 aligned perpendicular to the axial direction A and a plurality of mounting webs 72 for fixing the separating plate 71. The separating plate 71 is designed here in the form of a circular disk and has an outer diameter D2. In other embodiments, the separating plate 71 may also have a shape different from a circular disk and / or may have flow-guiding elements. In this case, the outer diameter D2 refers to the maximum outer diameter D2, i.e. the maximum radial extent of the separating plate 71.

[0070] The separator plate 71 is radially centrally disposed within the central inlet region 25, i.e., the center point of the separator plate 71 is on the central axis M of the rotor 10. In the axial direction A, the separator plate 71 is disposed such that, for each vane 103, the upper part of the leading edge 109 is disposed above the separator plate 71 in the axial direction A according to the figures (FIGS. 3 and 4), and the lower part of the leading edge 109 is disposed below the separator plate 71 in the axial direction A.

[0071] The entire area of ​​the vanes 103 arranged above the separator plate 71 in the axial direction A forms a first centrifugal wheel 105 which serves mainly to generate a main flow HF flowing from the inlet 21 to the outlet 22 in the axial direction A. The main flow HF is indicated by the arrow HF represented by a solid line.

[0072] The entire area of ​​the vanes 103 arranged below the separator plate 71 in the axial direction A forms a second centrifugal wheel 106 which serves mainly to generate a recirculation flow RF which is directed from the rear side of the rotor 10 facing away from the inlet 21 through the relief openings 104 towards the central inlet area 25. The recirculation flow RF is indicated by the dashed arrow RF.

[0073] The separation element 7 redirects the recirculation flow RF from the axial direction A to a radial direction. The separation element 7 prevents direct collision or contact between the mainstream HF and the recirculation flow RF in the region of the end of the relief opening 104 facing the central inlet region 25. The separation element 7 thus prevents the recirculation flow RF and the mainstream HF from meeting head-on, i.e., as flows directed in opposite directions. The separation element 7 therefore at least partially separates the recirculation flow RF from the mainstream HF in the region of the central inlet region 25. The recirculation flow RF is initially redirected radially by the separation element 7. Substantial mixing of the mainstream HF and the recirculation flow RF does not occur until the recirculation flow RF passes the outer edge of the separation plate 71. The outer edge of the separation plate 71 refers to the radially outer edge of the separation plate 71. Because the recirculation flow RF has already been redirected radially, it can mix with the mainstream HF with little to no significant turbulence.

[0074] As can be best seen in Figure 3, the outer diameter D2 of the separator plate 71 is smaller than the diameter D1 of the central inlet region 25. In this embodiment, the separator plate 71 is located entirely within the central inlet region 25 and does not physically contact the vanes 103. The leading edges 109 of the vanes 103 are disposed around the separator plate 71 without contacting it. This embodiment has the advantage that the separator plate 71 can be machined in a simple manner, for example during manufacture of the rotor 10.

[0075] The outer diameter D2 of the separation plate 71 is larger than the inner diameter of the relief opening 104, and therefore the relief opening 104 is completely covered by the separation plate 71. Therefore, the relief opening 104 is not visible from the inlet 21.

[0076] However, embodiments are also possible in which the relief opening 104 is partly visible from the inlet 21, i.e. the separator plate 71 does not completely cover the relief opening 104. For example, this can be achieved in that the outer diameter D2 of the separator plate 71 is smaller than the inner diameter of the relief opening 104.

[0077] The separation element 7 comprises mounting webs 72 for fixing the separation plates 71. All mounting webs 72 are arranged on the underside of the separation plates 71. Here, the underside of the separation plates 71 refers to the boundary surface of the separation plates 71 facing the relief openings 104. Each mounting web 72 extends from the underside of the separation plate 71 in the axial direction A to the cladding 102 on which the mounting web 72 is supported. The separation plates 71 are therefore fixed to the cladding 102 by the mounting webs 72. It is therefore no longer necessary to attach the separation plates 71, i.e. the separation elements 7, to the vanes 103.

[0078] 5, the mounting web 72 is radially arranged on a circle that is concentric with the relief opening 104 and has a diameter larger than the relief opening 104. The diameter of the circle on which the mounting web is arranged is smaller than the outer diameter D2 of the separator plate 71. Therefore, the mounting web 72 is arranged below the separator plate 71 so that it is not visible from the inlet 21 of the pump housing 2.

[0079] The mounting webs 72 are preferably spaced equidistantly around the relief opening 104. A total of five mounting webs 72 are provided. Between every two adjacent mounting webs, a radial opening 73 is provided, through which the recirculation flow RF can flow out of the relief opening 104 and radially toward the outlet 22.

[0080] Preferably, the attachment webs 72 are arranged so that the radial openings 73 are radially aligned with the gaps 74 between the leading edges 109 of two adjacent vanes 103. This can be best seen in FIG. 5 . Thus, the recirculation flow RF exiting the radial openings 73 can flow unimpeded through the gaps 74 between adjacent vanes 103. In this way, vortex formation in the recirculation flow RF is at least significantly reduced. This embodiment is particularly advantageous when the number of attachment webs 72 is equal to the number of vanes. In the embodiment described here, the rotor 10 has, by way of example, exactly five vanes. Thus, the separation element 7 has exactly five attachment webs 72, each of which is located on a connecting line between the central axis M of the rotor 10 and one of the leading edges 109 of the vanes 103. Thus, each of the five radial openings 73 is radially aligned exactly with one of the gaps 74 between adjacent vanes 103.

[0081] According to the present invention, the vanes 103, the separation element 7, and the relief opening 104 are designed as an integrated unit. Particularly preferably, the cladding 102 is also a component of this integrated unit. Furthermore, the cover plate 8 arranged on the vane 103 is also preferably a component of this integrated unit. Particularly preferably, the rotor 10 is designed as an integrated unit as a whole, except for the magnetically effective core 101. Therefore, in this embodiment, it is no longer necessary to connect the individual components of the rotor 10 to each other by joining methods such as gluing, welding, or screwing. The integrated unit has a monolithic design, i.e., it is a single piece and is not composed of several components. As a result, the integrated unit does not have any adhesives, screw connections, welded seams, seals, or contacts between adjacent components.

[0082] Due to the integral design of the unit comprising at least the vanes 103, the separating elements 7 and at least one relief opening 104, preferably all components of the rotor 10 except the magnetically effective core 101, the rotor 10 no longer needs to be assembled from several components but can be designed as a monolithic device.

[0083] This results in very high operational reliability, for example, because the individual components do not need to be joined by gluing, screwing or welding, and no seals are required between the individual components of the rotor 10 .

[0084] The integral unit may, for example, be designed as a one-piece injection-molded part, i.e., manufactured by an injection-molding process, which is preferably designed so that the magnetically effective core 101 is incorporated into the injection-molding process. For example, the magnetically effective core 101 may be sprayed with plastic in the injection-molding process, and the coating 102 may be manufactured in this way.

[0085] Preferably, rotor 10 is manufactured by combining an injection molding process with a subsequent subtractive machining method, such as a chip-removal machining method, such as milling or drilling.

[0086] Of course, other methods, such as additive manufacturing methods designated as 3D printing, are also suitable for manufacturing the rotor 10.

[0087] Preferably, the integrated unit is made of plastic. For example, the integrated unit may be injection molded from one of the following plastics:

[0088] Polyvinyl chloride (PVC), perfluoroalkoxy polymer (PFA), polypropylene (PP), polyethylene (PE).

[0089] It is also possible to manufacture the rotor 10 by a sintering process and subsequent subtractive machining. The cladding 102 is then made, for example, of powder or granules that are pressed onto the magnetically effective core 101 using pressure and optionally heat treatment so that it completely surrounds the magnetically effective core 101. Heat and / or pressure are applied to mold the plastic around the magnetically effective core 101 to form a monolithic block, for example a cylinder. The rotor 10, including the vanes 103, separation elements 7, at least one relief opening 104, and optionally the cover plate 8, is then brought to the desired shape by chip-removal machining.

[0090] Furthermore, in addition to or instead of powder or granules, it is possible to use heat and / or pressure to bond several plastic parts into a monolithic block, where the magnets are pre-inserted and completely enclose the magnets after the bonding process. The rotor 10, including the vanes 103, the separation elements 7, at least one relief opening 104, and optionally the cover plate 8, is then brought to the desired shape by chip-removal machining.

[0091] A first variant of the rotor 10 is shown in Figures 6 to 8. Figure 6 shows a cross-section of the rotor, the cross-section being along the axial direction A. Figure 7 shows a perspective view, partly in section, corresponding to the view of Figure 4. Figure 8 shows a cross-section of the first variant of the rotor 10 along the section line VIII-VIII in Figure 7. The view of Figure 8 corresponds to the view of Figure 5.

[0092] In the first variant of the rotor 10, several relief openings 104, 104a are provided. One of the relief openings 104 is again located at the center of the rotor 10, so that its axis coincides with the central axis M of the rotor 10. A number of additional relief openings 104a are arranged around the centrally located relief opening 104. By way of example, here, ten additional relief openings 104a are provided, which are arranged on a circle whose center point is on the central axis of the rotor 10. Each of the relief openings 104, 104a is designed as a cylindrical bore or opening extending from the central inlet region 25 in the axial direction A through the rotor 10 to its rear side. All of the relief openings 104, 104a are arranged parallel to one another. The circle on which the additional relief openings 104a are located has a diameter smaller than the outer diameter D2 of the separation plate 71 so that all of the relief openings 104, 104a are completely covered by the separation plate 71. Thus, neither of the relief openings 104, 104a is visible from the inlet 21.

[0093] However, embodiments are also possible in which one or more of the relief openings 104, 104a are partially or completely visible from the inlet 21, i.e. the separator plate 71 does not completely cover all of the relief openings 104, 104a. For example, this can be achieved in that the outer diameter D2 of the separator plate 71 is the same size as or smaller than the diameter of the circle on which the additional relief openings 104a are located.

[0094] A second variant of the rotor 10 is shown in Figures 9, 9A, 10, and 11. Figure 9 shows a cross-section of the rotor 10, the cross-section being along the axial direction A. Figure 9A shows the rotor 10 in a plan view from the inlet 21 of the pump housing 2. Figure 10 is a perspective view, partly in section, corresponding to the view in Figure 4. Figure 11 shows a cross-section of the second variant of the rotor 10 along the section line XI-XI in Figure 10. The view in Figure 11 corresponds to the view in Figure 5. The second variant of the rotor 10 also has only one centrally located relief opening 104. It will be understood that in such an embodiment of the second variant of the rotor 10, several relief openings 104, 104a can be provided, for example, in the same manner as described for the first variant of the rotor 10 (see Figure 8).

[0095] In a second variant of the rotor 10, the attachment webs 71 of the separation elements 7 are arranged on the outer edges of the separation plates 71, and the separation plates 71 are fixed to the attachment webs 71 of the separation elements 7. Each attachment web 72 extends radially outward from the outer edge of the separation plates 7. In addition, each attachment web 71 also extends in the axial direction A to the cladding 102, on which the attachment webs 71 are supported. In this embodiment, in which the attachment webs 72 are arranged on the outer edges of the separation plates 71, it is also preferred that the number of attachment webs 72, here five for example, is the same as the number of vanes 103 of the rotor 10. When viewed from the inlet, the separation elements 7 with the separation plates 71 and the attachment webs 72 arranged on their edges have a star-shaped appearance.

[0096] The mounting webs 72 are preferably arranged equidistantly on the outer edge of the separator plate 71. Between every two adjacent mounting webs 72 is arranged one of the radial openings 73 through which the recirculation flow RF can flow radially from the relief openings 104 towards the outlet 22.

[0097] Preferably, the mounting webs 72 are also positioned in the second variant of the rotor 10 so that the radial openings 73 are radially aligned with the gaps 74 between the leading edges 109 of two adjacent vanes 103. This can be best seen in FIG. 11. The recirculation flow RF exiting the radial openings 73 can therefore flow unimpeded through the gaps 74 between the adjacent vanes 103. In this way, vortex formation in the recirculation flow RF is at least significantly reduced.

[0098] In the second variant of the rotor 10, the separator plate 71 of the separator element 10 is also designed in the shape of a circular disk. As can be seen in FIG. 9 , in the second variant of the rotor 10, the outer diameter D2 of the separator plate 71 is smaller than the inner diameter of the centrally located relief opening 104. As a result, the separator plate 71 does not completely cover the relief opening 104, so that the relief opening 104 is partially visible from the inlet 21. A ring-shaped gap 104b exists around the separator plate 71, which is not covered by the separator plate 71 and is visible from the inlet 21 of the pump housing 2. This embodiment has the advantage that during the manufacture of the rotor 10, a milling tool can be inserted in the axial direction A into the ring-shaped gap 104b, thereby making it easier or more precise to machine the separator plate 71, especially in the region between two adjacent mounting webs 72.

[0099] Furthermore, the attachment web 72 preferably terminates radially a distance D3 forward of the leading edge 109 of the vane 103, D3 being large enough to allow a milling tool to fit between the attachment web 72 and the leading edge 109 of the vane 103. Thus, D3 is the radially measured distance between the radially outer end of the attachment web 72 and the leading edge 109 of the vane 103. In the embodiment shown in FIG. 11 , distance D3 is equal to the radially measured distance between the radially outer end of the attachment web 72 and the radially inner edge of the cover plate 8. From a practical standpoint, distance D3 is preferably at least 30 times larger, and preferably at least 15 times larger, than the axially measured distance A between the upper side of the cladding 102 on which the vane 103 is arranged and the upper side of the rotor 10 facing the inlet 21 of the inlet region 25 formed here by the cover plate 8. Naturally, such an embodiment of the rotor is also possible in a second variant in which the relief opening 104 is completely covered by the separating plate 71 and is therefore not visible from the inlet 21. For this purpose, for example, the outer diameter D2 of the separating plate 71 is larger than the inner diameter of the relief opening 104.

[0100] A third variant of the rotor 10 is shown in Figures 12 to 14. Figure 12 shows the rotor 10 in a plan view from the inlet of the pump housing 2. Figure 13 is a perspective view, partly in section, corresponding to the view in Figure 4. Figure 14 shows a cross-sectional view of the third variant of the rotor 10 along the section line XIV-XIV in Figure 13. The view in Figure 14 corresponds to the view in Figure 5.

[0101] The third variant of the rotor 10 is designed in a similar manner to the second variant, in particular with the attachment webs 72 arranged at the outer edge of the separator plate 71. However, the attachment webs 72 extend radially to the vanes 103. Each attachment web 72 therefore extends radially to the leading edge 109 of one of the vanes 103. Preferably, each attachment web 72 merges into one of the vanes 103. A rounded transition region 721 is preferably provided at the radially outer end of each attachment web 72, where the attachment web 72 merges into the leading edge 109 of the vane 103.

[0102] Furthermore, the present invention proposes a centrifugal pump 200 for conveying a fluid with a pump unit 1, which is designed according to the present invention. In a schematic cross-sectional view, FIG. 15 shows an embodiment of the centrifugal pump 200 according to the present invention. The centrifugal pump 200 comprises a stator 100 extending in the axial direction A from a first axial end 110 to a second axial end 120. A cup-shaped recess (not shown in FIG. 15) is provided at the first axial end 110, into which a cylindrical cup 31 of the pump unit 1 can be inserted. The stator 100, together with the rotor 10, forms an electromagnetic rotary drive for rotating the rotor 10 about the axial direction A. The stator 100 is designed as a bearing-drive stator, such that the rotor 10 can be magnetically driven and magnetically levitated without contact relative to the stator 100. The rotor 10 is passively magnetically stabilized in the axial direction A and actively magnetically levitated in a radial plane E perpendicular to the axial direction A.

[0103] The stator 100 comprises a stator housing, which for a better overview is not shown in Figure 15. However, the stator 100 may be designed in a similar manner to the stator 100' having, for example, a stator housing 130' shown in Figure 1, whereby a recess 121' is provided in the stator housing 130', into which the cylindrical cup 31 of the bottom 3 of the pump housing 1 is inserted.

[0104] Particularly preferably, the electromagnetic rotary drive comprising the rotor 10 and the stator 100 is designed as a temple motor, the stator 100 having a plurality of coil cores 125, each of which has a longitudinal leg 126 extending from a first end to a second end in the axial direction A and a transverse leg 127 arranged in a radial plane E at the second end of the longitudinal leg 126. The transverse leg 127 extends radially inward from the longitudinal leg 126 towards the rotor 10.

[0105] The first ends, i.e., the bottom ends as shown, of all of the longitudinal legs 126 are connected to one another by a back iron 122 for conducting magnetic flux.

[0106] The coil core 125 is circumferentially disposed around the rotor 10, such that the rotor 10 is disposed between the lateral legs 127 of the coil core 125. At least one concentrated winding 160 is provided on each longitudinal leg 126, such that the winding surrounds the respective longitudinal leg 126.

[0107] The electromagnetic fields required for magnetic driving and levitation of rotor 10 are generated by concentrated windings 160. These concentrated windings 160 therefore generate an electromagnetic field which, in operation, exerts a torque on rotor 10 in a manner known per se, thereby exerting a freely adjustable transverse force on rotor 10 in the radial direction, so that the radial position of rotor 10, i.e., the position of rotor 10 in a radial plane E perpendicular to axial direction A, can be actively controlled or adjusted. With respect to three further degrees of freedom, namely its position in axial direction A and its tilt relative to radial plane E perpendicular to the desired axis of rotation (two degrees of freedom), rotor 10 is passively magnetically levitated or stabilized by magnetic reluctance forces, i.e., rotor 10 cannot be controlled.

Claims

1. A pump unit for a centrifugal pump, the centrifugal pump comprising the pump unit and a stator (100) extending in an axial direction (A) from a first axial end (110) to a second axial end (120), a cup-shaped recess being provided at the first axial end (110), the pump unit (1) being insertable into the cup-shaped recess, the pump unit (1) having a pump housing (2) having an inlet (21) and an outlet (22) for a fluid to be conveyed, and a rotor (10) arranged in the pump housing (2) and having a plurality of vanes (103) for conveying the fluid, the rotor (10) being rotated about the axial direction (A), the pump unit (1) being designed for contactless magnetic levitation of the rotor (10) by the stator (100) and contactless magnetic driving of the rotor (10). a rotor (10) having a plurality of vanes (103) arranged around a central inlet region (25) of the rotor (10), the vanes (103) of the rotor (10) being arranged around the central inlet region (25) of the rotor (10), the rotor (10) having at least one relief opening (104, 104a) for generating a recirculation flow (RF) directed from a back side of the rotor (10) facing away from the inlet (21) towards the central inlet region (25) of the rotor (10), the rotor (10) further having a separation element (7) arranged in the central inlet region (25), the separation element (7) turning the recirculation flow (RF) in a radial direction perpendicular to the axial direction (A), characterized in that the vanes (103) of the rotor (10), the separation element (7), and the at least one relief opening (104, 104a) are designed as an integral unit.

2. 2. A pump unit according to claim 1, wherein there is provided exactly one relief opening (104) connecting the central inlet area (25) of the rotor to the rear side of the rotor (10).

3. 2. A pump unit according to claim 1, wherein several relief openings (104, 104a) are provided arranged around a central axis (M) of the rotor, each relief opening (104, 104a) connecting the central inlet area (25) of the rotor to the back side of the rotor (10).

4. 4. A pump unit according to claim 1, wherein the rotor (10) comprises a ring-shaped or disc-shaped magnetically effective core (101) and a cladding (102) completely surrounding the magnetically effective core (101), the cladding (102) being a component of an integral unit comprising the vanes (103) and the separating elements (7).

5. 5. A pump unit according to any one of claims 1 to 4, wherein the separating element (7) is designed and arranged such that the at least one relief opening (104, 104a) is partly visible from the inlet.

6. 6. A pump unit according to claim 1, wherein the separating element (7) comprises a separating plate (71) and a mounting web (72), the separating plate (71) having a maximum radial outer diameter (D2) that is at most as large as the diameter (D1) of the central inlet area (25) of the rotor (10), the mounting web (72) being designed to fix the separating plate (71).

7. 7. A pump unit according to claim 6, wherein the maximum outer diameter (D2) of the separator plate (71) is smaller than the diameter (D1) of the central inlet area (25) of the rotor (10).

8. 8. A pump unit according to claim 4 and claim 6 or 7, wherein each attachment web (72) extends from the separator plate (7) to the covering material (102), and the radial openings (73) for the recirculation flow (RF) are provided between any adjacent attachment webs (72).

9. 9. A pump unit according to claim 8, wherein each attachment web (72) extends from the underside of the separating plate (71) in the axial direction (A) to the cladding (102).

10. 9. A pump unit according to claim 8, wherein each attachment web (72) is arranged on an outer edge of the separator plate (7) and extends in the radial direction from said outer edge.

11. 11. A pump unit according to claim 10, wherein the attachment webs (72) are arranged equidistantly on the outer edge of the separator plate (71).

12. 12. A pump unit according to claim 10 or 11, wherein each attachment web (72) extends in said radial direction to one of said vanes (103).

13. 13. A pump unit according to any one of claims 10 to 12, wherein the number of attachment webs (72) is equal to the number of vanes (103).

14. A centrifugal pump for conveying a fluid, comprising a pump unit designed according to any one of claims 1 to 13 and comprising a cylindrical cup (31) for receiving the rotor (10) and a stator (100) extending in the axial direction (A) from a first axial end (110) to a second axial end (120), wherein a cup-shaped recess is provided at the first axial end (110), and the cylindrical cup (31) of the pump unit (1) can be inserted into the cup-shaped recess, and the stator (100) a stator (100) which, together with the rotor (10), forms an electromagnetic rotary drive for rotating the rotor (10) about the axial direction (A), the stator (100) is designed as a bearing and drive stator, such that the rotor (10) can be magnetically driven and magnetically levitated without contact relative to the stator (100), and the rotor (10) is passively magnetically stabilized in the axial direction (A) and actively magnetically levitated in a radial plane (E) perpendicular to the axial direction (A).

15. The electromagnetic rotary drive device is designed as a temple motor, and the stator (100) has a plurality of coil cores (125), each of which has a longitudinal leg (126) extending from a first end to a second end in the axial direction (A) and a transverse leg (126) extending radially from the longitudinal leg (126) at the second end of the longitudinal leg (126) and arranged in the radial plane (E).

15. The centrifugal pump of claim 14, further comprising: longitudinal legs (126) and transverse legs (127), wherein the coil core (125) is circumferentially arranged around the rotor (10) so that the rotor (10) is arranged between the transverse legs (127) of the coil core (125), and wherein at least one concentrated winding (160) is provided on each longitudinal leg (125), the winding surrounding the respective longitudinal leg (126).

Images