Device for conveying a liquid

Abstract

The invention relates to a device for conveying a liquid, comprising a shaft (29) which extends in a longitudinal direction (1) and has an impeller (28) held thereon; an electric motor (10) which can be actuated in two rotational directions (7, 8) and has a rotor (11) fixed to the shaft (29) and a stator (12) surrounding the rotor (11); a hydraulic housing which provides an inlet (25) for the liquid and a first pressure port (21) and a second pressure port (22) for the liquid; and a flow selector (30), one side of the flow selector (30) being fixed to the hydraulic housing at a bearing point (26). The flow selector (30) can be moved into a first selection position and into a second selection position and back on the basis of the rotational direction, and the flow selector (30) provides two sealing surfaces (31, 32). In the first selection position, the flow selector (30) closes the first pressure port (21) by means of a first sealing surface (31) or, in the second selection position, closes the second pressure port (22) by means of a second sealing surface (32), and the flow selector (30) tapers in the direction of the bearing point (26) preferably in the shape of a wedge and provides the sealing surfaces (31, 32) on two tapering surfaces lying opposite each other.

Description

[0001]

[0002] Applicant: Hanning Elektro-Werke GmbH & Co. KG

[0003] Holter Street 90

[0004] 33813 Oerlinghausen

[0005] Our reference HAN2405PCT1

[0006] Date: June 18, 2025

[0007] Device for conveying liquid

[0008] The invention relates to a device for conveying a liquid comprising a longitudinally extending shaft with a pump impeller held thereon, comprising an electric motor operable in two directions of rotation with a rotor fixed to the shaft and a stator encompassing the rotor, comprising a hydraulic housing which provides an inlet for the liquid as well as a first pressure port and a second pressure port for the liquid, and comprising a flow selector, wherein the flow selector is fixed on one side in a bearing point on the hydraulic housing, wherein the flow selector is moved into a first selection position and into a second selection position and back again depending on the direction of rotation of the electric motor and the pump impeller driven by it.wherein the flow selector provides two sealing surfaces and wherein the flow selector, in the first selection position, seals the first pressure port with a first sealing surface or, in the second selection position, seals the second pressure port with a second sealing surface.

[0009] US Patent 5984644 A discloses a device for conveying liquid with a flow selector that includes a thin, membrane-like sealing disc which is elastically deformable and supported on two sides. The sealing disc of the flow selector deforms depending on the direction of rotation and always closes one of the device's two pressure ports during operation.

[0010] From FR 1 142593 A, a device for conveying liquid is known, comprising a flow selector that is supported on one side and also has a thin sealing disc. The sealing disc is made of a sufficiently strong material that does not deform during intended use. To selectively close one of the two pressure ports, the flow selector with the sealing disc is pivoted or folded over depending on the direction of rotation of the pump impeller.

[0011] The object of the present invention is to advantageously further develop a device for conveying liquid.

[0012] To solve the problem, the invention in conjunction with the preamble of claim 1 is characterized in that the flow selector tapers in the direction of the bearing point, at least sectionally and preferably in a wedge shape, and provides sealing surfaces on two opposing tapered surfaces.

[0013] The particular advantage of the invention lies in the fact that the segmented wedge shape of the flow selector enables rapid actuation, resulting in a quick change of the selected position and the flow direction. The wedge-shaped geometry ensures that the switching path for closing one pressure port and opening the other is short. At the same time, the wedge-shaped geometry gives the flow selector a higher mass, which improves the closing effect and reduces the tendency to vibrate when the pump impeller is rotating.

[0014] The hydraulic housing of the device can, for example, be made up of multiple parts. The multi-part design of the hydraulic housing facilitates assembly.

[0015] For example, a hydraulic housing pot can be provided that accommodates or surrounds the impeller, along with a cover that seals against the hydraulic housing pot. The inlet can be located, for example, on the cover of the hydraulic housing, while the pressure ports can be located on the hydraulic housing pot. The pivot point for the flow selector can be located, for example, on the hydraulic housing pot, preferably between the first and second pressure ports.

[0016] In a preferred embodiment of the invention, sealing elements are provided as part of the sealing surfaces. These sealing elements are preferably designed as sealing lips, in particular as circumferential, annular sealing lips. The sealing effect is advantageously further improved by providing the sealing elements or sealing lips. At the same time, the sealing lips have a damping effect during the operation of the flow selector due to their elasticity, thus improving the operating and noise characteristics of the device. For example, the sealing elements can be implemented as sealing plateaus, i.e., raised surfaces, in particular disc-shaped ones, with a preferably circular cross-section adapted to the geometry of the pressure ports.The sealing lips or sealing plates are arranged in such a way that, in the first or second selection position, they enclose or cover a flow opening of the first pressure nozzle or a flow opening of the second pressure nozzle, respectively.

[0017] According to a further development of the invention, the flow selector is made of an elastic, deformable material. For example, a rubber-like material, preferably silicone and / or a thermoplastic elastomer (TPE), is used for the flow selector. Advantageously, the flow selector possesses inherent compliance due to the use of an elastic and deformable material. This inherent compliance results in a deformability that can be used to move the flow selector into the first and / or second selection position. The flow selector is then in a first or second deformation state in the first or second selection position, respectively.

[0018] For example, the flow selector can be undeformed in the first or second selector position and deformed in the other selector position. Alternatively, an additional neutral position for the flow selector can be provided, in which it is undeformed in an intermediate position, preferably between the first and second selector positions. In the first and second selector positions, the flow selector is then deformed.

[0019] According to a further development of the invention, the flow selector is manufactured in one piece. This one-piece design simplifies manufacturing and handling, for example, during assembly. It is also possible to form the sealing lips, which are optionally provided on the sealing surfaces, during the manufacturing process. The flow selector can be produced, for example, by primary forming or by an additive manufacturing process.

[0020] According to a further development of the invention, the flow selector has a receiving section and the hydraulic housing has a receptacle shaped correspondingly to the receiving section of the flow selector to form the bearing point. To secure the flow selector in the hydraulic housing, the receiving section is inserted into the receptacle. For example, the flow selector can be manufactured with an interference fit in the area of ​​the receiving section relative to the receptacle, so that the receiving section is inserted into the receptacle using the elasticity of the flow selector and is then held or secured therein with a force-fit and backlash-free connection.

[0021] According to a further development of the invention, the receiving section of the flow selector is formed in a substantially cylindrical shape. The cylindrical shape of the receiving section is suitable for primary forming or additive manufacturing.

[0022] Furthermore, the flow selector can be easily mounted using the cylindrical receiving section.

[0023] In a further development of the invention, a web section adjoins the receiving section of the flow selector on the side facing the sealing surfaces. The sealing surfaces of the flow selector extend to or adjoin this web section. The web section is thus arranged between the receiving section and the sealing surfaces of the flow selector. Advantageously, the web section can have a thin, slender, elongated shape. It thus forms the preferred, defined area for the elastic deformation of the flow selector when it is moved into the first or second selection position. Deformation of the flow selector in the area of ​​the sealing surfaces is avoided. The sealing effect of the flow selector is therefore further improved by providing the web section, on which the sealing surfaces are not located.At the same time, the flow selector can be fitted so tightly into the hydraulic housing in the area of ​​the web section that a rotational or tilting movement of the flow selector as a whole is blocked, or the flow selector cannot be tilted or pivoted as a whole. In this case, it is not absolutely necessary to manufacture the receiving section to an oversize.

[0024] According to a further development of the invention, the flow selector has a trapezoidal shape. In particular, it can be provided that on a side of the sealing surfaces opposite the bearing point, two outer surfaces are provided that taper towards a free end opposite the bearing point and serve as flow surfaces. The flow surfaces can, for example, be concavely curved or be shaped corresponding to an inner contour of the hydraulic housing, to which a first flow surface faces in the first selector position of the flow selector and a second flow surface faces in the second selector position. The flow surfaces are preferably located spatially adjacent to the impeller or facing it. They form a surface for the fluid to actuate and help ensure that the flow selector is actuated when the electric motor starts up and when the direction of rotation changes.Furthermore, they have a stabilizing effect during operation by ensuring that the flow selector remains securely in the first or second selection position during operation of the conveying device.

[0025] In a further development of the invention, the flow selector features a recess on the rear side of the flow selector, facing away from the inlet or towards the electric motor. The pump impeller or parts of the motor housing engage in this recess. This recess allows for a very compact design of the flow selector and enables its use even in confined spaces. At the same time, the response of the flow selector is improved by its close proximity to the pump impeller, as the flow selector is preferably positioned with its inflow surfaces in the fluid flow provided by the pump impeller. Preferably, the recess is formed in the area of ​​the inflow surfaces and extends to the free end of the flow selector.

[0026] According to a further development of the invention, the distance between the free end of the flow selector and the pump impeller, determined in a radial direction perpendicular to the longitudinal direction, is small, preferably in the range of 0 to 3 mm. Here, too, the favorable response behavior of the flow selector during a reversal of rotation is advantageous. Furthermore, the small distance and the very compact design due to the recess are also advantageous when the pump starts up from standstill, when the flow selector is moved from the neutral position to the first or second selection position, depending on the direction of rotation.

[0027] In a further development of the invention, a BLDC motor is used as the electric motor of the device. Advantageously, the use of the BLDC motor allows for a simple reversal of the direction of rotation and enables the speed to be varied or adjusted as required. Therefore, by using the BLDC motor, it is possible to vary the conveying direction and / or, by setting different operating points via the speed, to vary the conveying rate.

[0028] According to a further development of the invention, the undeformed flow selector is designed symmetrically with respect to a body center plane thereof. Preferably, a longitudinal center axis of the shaft of the conveying device extends in the body center plane in the neutral position of the flow selector.

[0029] Further advantages, features, and details of the device according to the invention can be found in the dependent claims, the drawings, and the following description. Features mentioned therein can be essential to the invention individually or in any combination. Thus, the disclosure relating to the individual aspects of the invention can always be referenced reciprocally. The drawings serve only as examples to clarify the invention and are not limiting in nature. They show:

[0030] Fig. 1 shows a side view of a device for conveying liquid in a first embodiment with a first pressure nozzle and with a second pressure nozzle.

[0031] Fig. 2 shows an end-face view of the device according to Fig. 1.

[0032] Fig. 3 shows a partial longitudinal section through the device according to Fig. 2,

[0033] Fig. 4 shows a cross-section through the device according to Fig. 1 with a flow selector in a neutral position, wherein the flow selector is provided in a hydraulic housing pot of a multi-part hydraulic housing,

[0034] Fig. 5 shows a partial view of the hydraulic housing pot with a receptacle for the flow selector,

[0035] Fig. 6 shows the representation according to Fig. 4 with the flow selector in a first selection position,

[0036] Fig. 7 shows the representation according to Fig. 4 with the flow selector in a second selection position,

[0037] Fig. 8 shows a perspective view of the flow selector of the device in the first embodiment,

[0038] Fig. 9 shows an end-face view of the flow selector of the device in the first embodiment,

[0039] Fig. 10 shows a side view of the flow selector of the device in the first

[0040] embodiment, Fig. 11 a front view of the device for conveying liquid in a second embodiment without a lid and

[0041] Fig. 12 shows a partial longitudinal section through the device according to Fig. 11.

[0042] A first embodiment of a device for conveying a liquid is shown in Figures 1 to 10. The device comprises a shaft 29 extending in a longitudinal direction 1, a pump impeller 28 held non-rotatably on the shaft 29, and an electric motor 10. The electric motor 10 is exemplary designed as a BLDC motor and can be operated in two opposite directions of rotation 7, 8. The electric motor 10 includes a rotor 11 held non-rotatably on the shaft 29 and a stator 12 that surrounds the rotor 11 on the outside.

[0043] The impeller 28 is fixed at one end to the shaft 29. It is located in a hydraulic housing of the device. The hydraulic housing is a multi-part design. In particular, it includes a hydraulic housing pot 20, which receives and surrounds the impeller 28. Furthermore, the hydraulic housing comprises a cover 24, which is attached to the hydraulic housing pot 20. The cover 24 provides an inlet 25 for the fluid. The inlet 25 is arranged coaxially with the shaft 29.

[0044] In addition to the hydraulic housing, the device includes a motor housing 13 for the electric motor 10. The motor housing 13 comprises a canned tube 14 with a canned tube flange and a canned tube housing. The canned tube housing accommodates the rotor 11 of the electric motor 10. A substantially cylindrical outer shell portion of the canned tube housing extends within an air gap that is functionally necessary between the rotor 11 and the stator 12.

[0045] In the area of ​​the canned tube flange, a bearing support 15 is provided, which accommodates a bearing 16 for the shaft 29, in this case a sliding bearing bushing, and serves to support the shaft 29 on the side facing the impeller 28. Additionally, a seal 17 is arranged in the canned tube flange of the canned tube 14, and a sealing element 18 is arranged between the seal 17 and the impeller 28, defining the transition between the motor housing 13 and the hydraulic housing. The electric motor 11 of the device, which can be operated in a direction-variable manner, serves to discharge the fluid from the hydraulic housing, depending on the respective direction of rotation 7, 8, either via a first drain port 21 or a second drain port 22. The drain ports 21, 22 are formed as part of the hydraulic housing housing 20.Fluid lines (not shown) are connected to the pressure ports 21, 22 as well as to the inlet 25, which can be used, for example, to pump the liquid in a flushing circuit or to pump it out into a sink.

[0046] To vary the flow direction of the fluid depending on the direction of rotation, the device provides a flow selector 30. The flow selector 30 is located in the hydraulic housing housing 20. A bearing point 26 secures the flow selector 30 in the hydraulic housing housing 20.

[0047] The flow selector 30 is manufactured in one piece from an elastic, deformable material, for example a thermoplastic elastomer (TPE) or silicone. In a first selection position, it closes the first pressure port 21 (see Fig. 6) and in a second selection position (see Fig. 7) the second pressure port 22.

[0048] The flow selector 30 has two sealing surfaces 31, 32 arranged at an angle to each other and tapering towards the bearing point 26. In the first selector position, the first sealing surface 31 of the flow selector 30 seals the first pressure port 21. In the second selector position, the second sealing surface 32 of the flow selector 30 seals the second pressure port 22. The sealing effect is improved by two sealing lips 35, 36, which are formed as part of the sealing surfaces 31, 32. The sealing lips 35, 36 are circumferential and annular, respectively. In the first and second selector positions, they enclose a flow opening of the first pressure port 21 and a flow opening of the second pressure port 22, respectively.

[0049] On the side of the sealing surfaces 31, 32 facing the bearing point 26, the flow selector 30 provides a receiving section 33 and a web section 34 between the receiving section 33 and the sealing surfaces 31, 32. The receiving section 33 is cylindrical. To form the bearing point 26, it engages in a receptacle 23, which is shaped correspondingly to the cylindrical form of the receiving section 33 and is located on the hydraulic housing housing 20. The flow selector 30, made of an elastic material, is manufactured with an interference fit in the area of ​​the receiving section 33 relative to the inner contour of the receptacle 23, so that the flow selector 30, together with the receiving section 33, is pressed into the receptacle 23 and is then held therein by frictional engagement.In addition, the flow selector 30 is fitted section by section into the hydraulic housing pot 20 in the area of ​​the web section 34 in such a way that a rotation or tilting movement of the flow selector 30 is completely blocked.

[0050] The web section 34 forms the part of the flow selector 30 that is preferably deformed when the latter is moved into the first or second selection position. The flow selector 30 is thus elongated, thin, and flexible in the web section 34. While the web section 34 is oriented in a radial direction 4 extending perpendicular to the longitudinal direction 1 in a neutral position of the flow selector provided between the first and second selection positions (see Fig. 4), the web section 34 is bent or curved in the first and second selection positions.

[0051] On one side of the sealing surfaces 31, 32 opposite the receiving section 33 or the web section 34, the flow selector 30 provides two inflow surfaces 37, 38. The inflow surfaces 37, 38 converge towards a free end 42 of the flow selector 30. The flow selector 30 tapers in the region of the inflow surfaces 37, 38 towards the free end 42. It therefore has an approximate trapezoidal shape in the region of the sealing surfaces 31, 32 and the inflow surfaces 37, 38. In its undeformed state, it is symmetrical with respect to a body midplane 3, which extends through the receiving section 33 and the web section 34 and provides the sealing surfaces 31, 32 and the inflow surfaces 37, 38 on both sides.

[0052] In the area of ​​the inflow surfaces 37, 38, the flow selector 30 is concavely curved. A surface of the inflow surfaces 37, 38 is shaped correspondingly to an inner contour of the hydraulic housing pot 20 such that, in the first selected position of the flow selector 30, a first inflow surface 37 is at least partially in contact with an inner surface of the hydraulic housing pot 20. Similarly, in the second selected position of the flow selector 30, a second inflow surface 38 of the flow selector 30 is at least partially in contact with an opposite inner surface of the hydraulic housing pot 20.

[0053] The inlet surfaces 37, 38 on the side of the flow selector 30 facing the impeller 28 serve, firstly, to move the flow selector 30 into the first or second selection position depending on the direction of rotation 7, 8 of the impeller 28. During operation of the pumping device, they are located in a flow provided by the liquid 28, so that the liquid moves the flow selector 30 into the first selection position when the impeller 28 rotates in the first direction 7 and into the second selection position when the impeller 28 rotates in the second direction 8.

[0054] At the same time, the inflow surfaces 37, 38 help to keep the flow selector 30 stable in the first selection position or in the second selection position as long as the pump impeller 28 is rotated in the corresponding direction of rotation 7, 8.

[0055] To ensure the best possible and fastest actuation of the flow selector 30, or a short actuation time when moving it from the neutral position to the first or second selection position, the distance 5 in the radial direction 4 between the free end 42 of the flow selector 30 facing the impeller 28 and the impeller 28 itself is small. In the neutral position, this distance is preferably less than 5 mm. Due to the close spatial proximity of the flow selector 30 to the impeller 28, a high degree of interaction with the fluid flow is achieved. The flow selector 30 is then reliably actuated and exhibits a rapid response.

[0056] An additional close spatial relationship between the flow selector 30 and the impeller 28 is achieved by a recess 41 in the flow selector 30. The recess 41 is provided on the rear side 40 of the flow selector 30 facing the electric motor 10, in the area of ​​the inflow surfaces 37, 38 and the free end 42. A part of the motor housing 30, in this case the canned tube flange, engages in the recess 41. The recess 41 is provided to achieve a compact design and high hydraulic efficiency of the device. Figures 11 and 12 show a second embodiment of the conveying device, which adopts essential functional features of the first embodiment. The common functional features of the embodiments will not be discussed again below. Reference is made to the preceding description with regard to these common functional features.

[0057] The conveying device according to the second embodiment differs essentially from the first embodiment in the geometry of the flow selector 30, and in particular in the design of the inflow surfaces 37, 38. According to the second embodiment, the flow selector 30 projects beyond the impeller 28 in the direction of the radial direction 4, which is oriented perpendicular to the longitudinal direction 1, on a front face 39 opposite the electric motor 10. The flow selector 30 is arranged between the inlet 25 of the pump housing and within the impeller 28. At the same time, the flow selector 30 does not project beyond the longitudinal center axis 2; that is, a second distance 6, defined in the radial direction 4, between the free end 42 of the flow selector 30 and a longitudinal center axis 2 extending coaxially to the shaft 29 in the longitudinal direction 1 is greater than 0 mm. This second distance 6 is therefore considerably smaller than the radius of the impeller 28 defined in the radial direction 4.By ensuring that the flow selector 30 does not extend beyond the longitudinal center axis 2 of the device, a safe and fast response is guaranteed, since the flow surfaces 37, 38 do not extend into the counterflow, which forms on the half of the hydraulic housing opposite the flow selector 30 when the pump impeller 28 rotates, even in the neutral position of the flow selector 30.

[0058] In the second embodiment of the device, the flow selector 30 also has a recess 41 on its rear side 40 facing the electric motor 10. In this case, the recess 41 serves to create space for the pump impeller 28, which engages in the recess 41. As before, the recess 41 results in a compact design and improves the hydraulic efficiency.

[0059] Identical components and component functions are identified by the same reference symbols.

[0060] marked. Reference numeral list

[0061] 1 Longitudinal direction

[0062] 2 Longitudinal center axis

[0063] 3 Body midplane 4 Radial direction

[0064] 5 distance

[0065] 6 distance

[0066] 7 Direction of rotation

[0067] 8 Direction of rotation

[0068] 10 Electric motor

[0069] 11 Rotor

[0070] 12 Stator

[0071] 13 Motor housing

[0072] 14 split tube

[0073] 15 bearing supports

[0074] 16 warehouses

[0075] 17 Seal

[0076] 18 Closure body 20 Hydraulic housing pot 21 Pressure nozzle

[0077] 22 pressure ports

[0078] 23 recording

[0079] 24 lids

[0080] 25 inflows

[0081] 26 bearing point

[0082] 28 Pump wheel

[0083] 29th wave

[0084] 30 Flow selector 31 Sealing surface

[0085] 32 sealing surface

[0086] 33 Intake section Bridge section Sealing lip Sealing lip Inlet surface Inlet surface Front Rear Recess Free end

Claims

Patent claims 1. Device for conveying liquid comprising a shaft (29) extending in a longitudinal direction (1) with a pump impeller (28) held thereon, comprising an electric motor (10) operable in two directions of rotation (7, 8) with a rotor (11) fixed to the shaft (29) and a stator (12) encompassing the rotor (11), comprising a hydraulic housing which provides an inlet (25) for the liquid as well as a first pressure port (21) and a second pressure port (22) for the liquid, and comprising a flow selector (30), wherein the flow selector (30) is fixed on one side in a bearing point (26) on the hydraulic housing, wherein the flow selector (30) can be moved into a first selection position and into a second selection position and back depending on the direction of rotation, wherein the flow selector (30) has two sealing surfaces (31,32) and wherein the flow selector (30) in the first selection position closes the first pressure port (21) with a first sealing surface (31) or in the second selection position closes the second pressure port (22) with a second sealing surface (32), characterized in that the flow selector (30) preferably tapers in a wedge shape towards the bearing point (26) and provides the sealing surfaces (31, 32) on two opposing tapered surfaces.

2. Device according to claim 1, characterized in that the sealing surfaces (31, 32) provide sealing elements that can be applied to the pressure nozzles (21, 22), wherein the sealing elements are preferably designed as circumferential, annular sealing lips (35, 36) or as sealing plateaus.

3. Device according to claim 1 or 2, characterized in that the flow selector (30) is made of an elastic, deformable material.

4. Device according to one of claims 1 to 3, characterized in that the flow selector (30) is manufactured in one piece and / or consists of a rubber-like material and preferably consists of silicone and / or a thermoplastic elastomer.

5. Device according to one of claims 1 to 4, characterized in that the flow selector (30) has a receiving section (33) to form the bearing point (26), that a receiving section (23) corresponding to the receiving section (33) is formed on the hydraulic housing, and that the receiving section (33) of the flow selector (30) is inserted into the receiving section (23).

6. Device according to claim 5, characterized in that the receiving section (33) of the flow selector (30) is cylindrical and / or that a web section (34) adjoins the receiving section (33) of the flow selector (30) on a side facing the sealing surfaces (31, 32) and / or that the sealing surfaces (31, 32) of the flow selector (30) extend to the web section (34) of the flow selector (30) and / or adjoin the web section (34).

7. Device according to claim 6, characterized in that the web section (34) of the flow selector (30) is elastically deformed and preferably bent in the first selection position and in the second selection position.

8. Device according to one of claims 1 to 7, characterized in that the flow selector (30) is designed symmetrically with respect to a body center plane (3) thereof.

9. Device according to one of claims 1 to 8, characterized in that the flow selector (30) has a trapezoidal shape and / or provides two flow surfaces (37, 38) tapering towards a free end (42) of the flow selector (30) on a side of the sealing surfaces (31, 32) opposite the bearing point (26), wherein the flow surfaces (37, 38) are preferably concave and / or are shaped corresponding to an inner contour of the hydraulic housing, to which a first flow surface (37) in the first selection position of the flow selector (30) and a second flow surface (38) of the flow selector (30) in the second selection position are directed.

10. Device according to one of claims 1 to 9, characterized in that the flow selector (30) provides a recess (41) on a rear side (40) facing away from the inlet (25) and / or towards the electric motor (10), wherein the pump impeller (28) and / or parts of a motor housing (13) engage in the recess (41) of the flow selector (30) and / or wherein the recess (41) is provided in the area of ​​the inflow surfaces (37, 38) and / or extends to the free end (42) of the flow selector (30).

11. Device according to one of claims 1 to 10, characterized in that a first distance (5) between the free end (42) of the flow selector (30) and the pump impeller (28) is determined in a radial direction (3) oriented perpendicular to the longitudinal direction (1) is a maximum of 5 mm.

12. Device according to one of claims 1 to 10, characterized in that the flow selector (30) projects beyond the pump impeller (28) in a radial direction (4) oriented perpendicular to the longitudinal direction (1) on a front side opposite the electric motor (10) and / or facing the inlet (25).

13. Device according to one of claims 1 to 12, characterized in that a second distance (6) determined in the radial direction (4) between the free end (42) of the flow selector (30) and a longitudinal central axis (2) extending coaxially to the shaft (29) in the longitudinal direction (1) is greater than 0 mm.

14. Device according to one of claims 1 to 13, characterized in that the electric motor (10) is designed in the manner of a BLDC motor.

15. Use of a BLDC motor as an electric motor (10) of a device according to any one of claims 1 to 14.

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