PUMP IMPELLER, HOUSING ELEMENT AND PUMP HEREBY

Description

[0001] The invention relates to a free-flow impeller pump according to the preamble of claim 1.

[0002] The main features of the invention are specified in the characterizing part of claim 1. Embodiments are the subject of claims 2 to 15.

[0003] The invention relates in particular to components of free-flow impeller pumps, which are also commonly referred to as vortex pumps. Free-flow impeller pumps are frequently used in wastewater pumping. Wastewater is characterized by the fact that its exact composition is often unknown. It frequently contains a high proportion of solids, such as long fibrous materials, coarse components like stones, or chemically aggressive substances. While free-flow impeller pumps offer reliable and robust pump operation, their efficiency is often somewhat reduced compared to other pump hydraulics.

[0004] WO 2017 / 001340 A1 discloses a pump impeller with two opposing blade groups. The blades have a non-homogeneous material thickness. DE 35 20 263 A1 describes a pump impeller with blades featuring blade covers. Each pump impeller has a single blade type.

[0005] From EP 1 134 420 A2, a free-flow pump is known in which a free space is formed between a pump inlet and a free-flow impeller. To increase efficiency, the inner wall of the housing is provided with a flow-improving or friction-reducing microstructure, in particular a surface structure or layer, in the area of ​​the free space. This can be concentric rings similar to sharkskin. Viewed from the main flow direction, this creates a friction-reduced component surface leading towards the flow outlet.

[0006] The invention is based on the objective of increasing the efficiency of a pump, and in particular a free-flow impeller pump, while maintaining a constant power consumption, thereby optimizing flow control and thus resource efficiency. The solution should enable reliable, continuous operation and be cost-effective.

[0007] The problem is solved by the characterizing features of claim 1.

[0008] The invention relates to a free-flow impeller pump with a pump housing in which a pump impeller designed as a free-flow impeller is rotatably mounted, with which a fluid medium can be conveyed from a pump inlet of the pump housing to a pump outlet of the pump housing, wherein the pump housing comprises a housing element. The housing element has an inner wall that delimits a flow channel for a fluid medium extending along a central axis, the cross-section of which increases in a main flow direction. The flow channel of the housing element is arranged between the pump inlet and the pump impeller, wherein the housing element forms a wall of a pump hydraulic system and the pump impeller is arranged in an impeller chamber of the pump hydraulic system, wherein a free space without further flow-guiding elements is formed between the housing element and the pump impeller within the impeller chamber.The inner wall of the housing has a surface structure designed to counteract backflow against the main flow direction along the inner wall of the housing of the fluid medium.

[0009] This optimizes the pump's efficiency. The surface structure of the housing element reduces backflow. This surface structure increases pressure build-up within the pump housing because it minimizes backflow into the pump's suction area. The surface structure particularly favors flow in the main flow direction. This minimizes power loss from the pump, and larger flow rates are delivered more efficiently. The flow path is optimized. The surface structure can therefore have at least one inlet surface that projects transversely into the backflow. This inlet surface creates turbulence in the backflow and reduces it accordingly. Preferably, no inlet surfaces projecting transversely into the rotational flow are present in the circumferential direction. This way, the rotation initiated by the pump impeller is not slowed down, only the backflow.The aforementioned advantages are particularly evident in the free-flow impeller pump according to the invention.

[0010] According to a more detailed embodiment, the surface structure has at least one step. The step forms the upstream flow area and counteracts backflow. Furthermore, the step creates a shadow for the main flow direction, in which a low pressure is generated when water flows over it. Backflow is then not only impeded at the step, but the main flow also draws the backflow back into the main flow. The step can, in particular, project transversely into the backflow. The step can also be rotationally symmetrical. The step can be designed with an undercut, especially such that the backflow flows at least slightly beneath the step. In the main flow direction, this undercut hardly disturbs the flow. With respect to the backflow, the undercut can enhance its deflection. For this purpose, the undercut can form a radius. No undercuts should be formed in the main flow direction.This improves demoldability. Ideally, demolding slopes of at least 1.5° are maintained along the main flow direction. Furthermore, no constrictions in the main flow direction should be formed in the flow channel between several steps.

[0011] Furthermore, it is advantageous if at least one step is ring-shaped or at least segment-shaped. The ring-shaped or segment-shaped step can extend circumferentially around the central axis. This design makes the counteracting effect particularly efficient, and the step itself is also cost-effective to create.

[0012] Furthermore, it is advantageous if the surface structure has at least one, two, or three additional steps. The steps are spaced apart from each other in a direction radial to the central axis and / or the main flow direction. The spacing and the number of steps can be adapted to the respective pump size. Optionally, the surface structure can also have at least five, at least six, at least ten, or significantly more than ten steps. The surface structure resulting from the additional steps further reduces backflow. Preferably, the step(s) are a macrostructure. For this purpose, the step preferably has a height of at least 0.5 mm, at least 1.0 mm, at least 2.0 mm, or at least 3.0 mm.

[0013] Preferably, the additional steps are arranged at uniform intervals in the direction radial to the central axis and / or the main flow direction. These additional steps can be annular or at least annular segment-shaped. The additional annular or at least annular segment-shaped steps can extend circumferentially around the central axis. This suppresses backflow particularly efficiently.

[0014] Alternatively, it can be advantageous if the step is spirally shaped and preferably wound radially outwards from the central axis, preferably by more than 360°, 720°, 1080°, or significantly more revolutions. This also effectively suppresses backflow. The optional upward spiral of the step towards the pump impeller improves flow guidance towards the impeller.

[0015] Furthermore, it can be advantageous for the step to have a wedge-shaped or trapezoidal cross-sectional profile. This allows for the formation of an undercut. This refers to the basic shape, although radii can also be formed on the edges. The backflow flows into this undercut and is slowed down. This suppresses the backflow particularly efficiently. In the main flow direction, however, the fluid simply flows over the step. Other alternatives include a round or oval cross-section. In principle, numerous different basic shapes are possible for the step. Preferably, however, these do not form a flow obstruction in the main flow direction, but only against it.

[0016] In a specific embodiment, the step is designed as a ledge. A ledge is characterized in particular by the fact that one descends the ledge in the direction of the main flow and ascends it against the direction of the main flow. With optionally several ledge-like landings, a staircase of steps results.

[0017] Furthermore, it can be advantageous if the inner wall of the housing has a conical shape on which the surface structure is formed. The inner wall of the housing preferably widens in the main flow direction. This makes the housing element particularly suitable for a free-flow impeller pump. Preferably, the conical shape is straight. This minimizes obstruction of fluid vortices within the housing element. However, skewed conical shapes are also possible, especially slightly skewed ones. This allows, for example, the pump connection to be positioned somewhat differently. Preferably, the conical shape is a shallow cone, specifically a cone with an opening angle of at least 20 degrees.

[0018] Furthermore, it can be advantageous if the housing element has a fluid inlet opening in the main flow direction at the beginning of the flow channel, with the fluid inlet opening being aligned with the central axis. In the assembly, the fluid inlet opening can be positioned particularly in the area of ​​the pump inlet. For example, a cover forming the housing element can thus also be suitable for forming the pump inlet of a free-flow impeller pump.

[0019] It can also be advantageous if the housing element is designed as a removable cover for a pump housing, particularly the pump itself. The cover is removable in the sense that it is attached to at least one other element of the housing by means of at least one removable fastening element. Typical fastening elements are screws and / or clamps. The removable cover can be designed with a mounting flange and preferably has screw holes. Since the cover is removable, the housing element can be disassembled and is then easy to service and, where necessary, replace. Alternatively or additionally, the housing element can form an impeller chamber of a pump housing. It is precisely here that potential backflows form on the inner wall due to the resulting vortex and the pressure at the pump outlet, which can be reduced accordingly with the housing element.Another alternative or supplementary design can consist of the housing element being an insert element in an impeller chamber of a pump housing. Such insert elements can be mounted inside an impeller chamber (e.g., screwed in place) and replaced as needed, particularly if, for example, abrasion or deposits impair the function of the step(s).

[0020] It can be advantageous if the pump impeller is positioned in the direction of the main flow relative to the housing element. The central axis of the housing element can be parallel and / or coaxial with the axis of rotation of the pump impeller.

[0021] Preferably, the pump hydraulics are radial pump hydraulics. The pump inlet should be aligned with the pump impeller. Preferably, the pump outlet is oriented orthogonally to the pump inlet and leads radially from the pump impeller out of the impeller chamber.

[0022] According to an inventive aspect, the pump impeller has an impeller surface and a direction of rotation, wherein blades are arranged on the impeller surface, at least one of the blades being a blade of the first type, and wherein the blade geometry of the blade of the first type has a blade edge that is inclined forward in the direction of rotation. The inclination of this edge contributes to drawing the vortex generated in front of the pump impeller more strongly into the pump impeller, in particular between the individual blades. The inclination can be formed by a slope and / or a radius. Furthermore, the inclination can be configured to begin at the impeller surface or to begin at a distance from the impeller surface.

[0023] Optionally, all of the pump impeller blades can be of the first type. This significantly increases the efficiency of the pump impeller compared to versions without such a blade edge.

[0024] According to a further inventive aspect, the pump impeller has an impeller surface on which blades are arranged, wherein at least one of the blades is a blade of the first type, wherein at least one of the blades is a blade of the second type, wherein the blade geometry of the blade of the first type differs from the blade geometry of the blade of the second type.

[0025] This achieves a functional separation into the intake of the fluid into the space between the blades and its retention there, followed by radial outward acceleration along the blades. The different blade geometries can be coordinated in such a way that the flow of the pumped fluid through the impeller is optimized by avoiding turbulence. Impellers of this type thus have a greater delivery head than impellers that only have blades of one type with a uniform geometry. The power consumption of the impeller according to the invention is comparable to that of impellers known from the prior art, and therefore the efficiency is increased.

[0026] According to an optional variant of this pump impeller, the blade geometry of the first type features a blade edge that is inclined forward in the direction of rotation. This contributes significantly to pumping fluid into the space between the blades.

[0027] The pump impeller preferably has a (preferred) direction of rotation (hereinafter simply referred to as the direction of rotation, even though the impeller could theoretically also be driven in reverse) and / or an imaginary axis of rotation around which the pump impeller is intended to rotate during operation. The imaginary axis of rotation (hereinafter sometimes simply referred to as the axis of rotation) runs, for example, through an impeller hub in the impeller surface, which serves for mounting to a drive shaft. The impeller hub can, for example, be a shaft receptacle and, in particular, be designed as a bore in the impeller surface (e.g., with a keyway) or a shaft journal (e.g., with a keyway and / or, for example, cylindrical or conical). The axis of rotation is aligned parallel and / or coaxially with the drive shaft and / or the bore. It runs transversely, preferably orthogonally, to the impeller surface.

[0028] The impeller surface should consist of an impeller base or plate oriented transversely to the axis of rotation, with the axis of rotation passing through its center. The impeller surface is closed and designed such that the conveyed fluid exits the impeller radially, thus being discharged transversely, and in particular perpendicularly, to the axis of rotation.

[0029] The blades have a pressure surface that points forward in the direction of rotation and a suction surface that points backward in the direction of rotation. The basic body of the blade geometry of the first type and / or the second type can extend outwards from the axis of rotation in such a way that it is straight (straight blades) and optionally oriented orthogonally to the axis of rotation. Alternatively, the basic body can have a curvature extending outwards from the axis of rotation (curved blades), which extends particularly over the impeller surface and is greater than 0° and up to 270°.

[0030] Furthermore, the impeller may be characterized by the blade geometry of the blades of the first type and / or the blades of the second type extending radially outwards from the axis of rotation, exhibiting a convex blade pressure surface and / or a concave blade suction surface. The shape of the blade suction surface and / or the blade pressure surface may be circular segment and / or cylindrical segment.

[0031] Furthermore, it can be advantageous if the blade pressure surface and / or the blade suction surface of the blade edge is inclined forward in the direction of rotation. The forward inclination has a positive effect on pressure build-up. Additionally, the blade of the first type can be divided along a curve and / or a kink into a base body and the blade edge, with the blade edge preferably being arranged at a distance from the impeller surface. The inclination is achieved by the curve or kink.

[0032] The blade edge can be inclined at an angle w1 relative to an imaginary plane of rotation in which the impeller surface rotates (during operation) in the direction of rotation. This angle w1 is preferably between 55° and 87°, between 60° and 80°, or between 65° and 75°. This contributes to optimizing the flow guidance. Furthermore, it is advantageous if the blade geometry of the first type has a convex pressure surface and a concave suction surface, wherein, in particular, the convex pressure surface has the angled blade edge and / or the concave suction surface has the angled blade edge. The blade edge preferably has a free end to which no further element of the blade is connected. Optionally, however, it is also possible to provide a blade of the first type with an inclined blade edge with an additional blade cover that extends beyond the suction surface.

[0033] Furthermore, it can be advantageous if the blade edge is arranged on a base body of the blade geometry of the first type, wherein the base body adjoins the impeller surface and, in particular, the blade edge is arranged at a distance from the base body, and especially forms a free end. The base body optimizes the momentum transfer to the fluid medium.

[0034] An optional aspect of the invention is that the blade geometry of the second type comprises a base body connected to the impeller surface and a blade cover connected to the base body, with a conveying channel formed between the blade cover, the base body, and the impeller surface. The blade cover contributes to optimized flow guidance by reducing turbulence. This reduces turbulence in the conveying channel. The conveying channel is bounded on three sides by the blade cover, the base body, and the impeller surface. It ensures higher dynamic pressure within the flow guided therein. It may be advantageous if the blade geometry of the first type does not include a blade cover.It is particularly advantageous if the blades of the first and second type are arranged alternately in the direction of rotation, with the blades of the second type having blade covers and the blades of the first type not having blade covers. The blades can be arranged with a uniform rotational angular spacing. Optionally, however, it is also possible to create an unequal distribution of the blades. In this case, it would be advisable to always arrange two adjacent blades closer together as a pair than to an adjacent pair. The greater distance is then preferably formed between the optional blade edge and the opposite blade cover. The greater blade spacing should be formed between the blade of the first type equipped with a blade edge and the second type blade, which is arranged in front of it in the direction of rotation and is equipped with a blade cover.In other words, the opening angle between the blade pressure surface of the first type and the blade suction surface of a second type arranged in front of it in the direction of rotation is greater than the opening angle between the blade pressure surface of the second type and the blade suction surface of a first type arranged in front of it in the direction of rotation.

[0035] Furthermore, it can be advantageous if the pump impeller has a direction of rotation and a blade channel formed in the direction of rotation between the second type of blade and another of the blades is partially covered by the blade cover. This allows for particularly effective optimization of the flow path and minimization of turbulence. The partial cover ensures sufficient flow into the conveying channel.

[0036] It can be advantageous for the blade cover to cover between 30% and 70% of the blade channel in the direction of rotation, leaving a gap along the channel. This gap can extend over the full length of the blade channel, with the length extending radially to the axis of rotation, i.e., from the inside out. The blade cover covers a width of the blade channel, with this width extending in the direction of rotation. The delivery channel is open at a radially outer edge of the impeller on the outer circumference of the pump impeller, allowing the pumped fluid to exit the delivery channel radially to the axis of rotation. This feature further optimizes flow guidance and minimizes turbulence.

[0037] It is also advantageous if the base body is aligned parallel to the axis of rotation with a maximum deviation of + / - 20°, preferably + / - 10°, more preferably + / - 5°, and particularly preferably + / - 2°. Furthermore, the base body can be aligned orthogonally to the impeller surface with a maximum deviation of + / - 20°, preferably + / - 10°, more preferably + / - 5°, and particularly preferably + / - 2°. In this way, the base body sits almost directly on the impeller surface or extends perpendicularly (+ / - the specified deviation) from the impeller surface. These aspects optimize the flow guidance and minimize turbulence.

[0038] Furthermore, it can be advantageous if the blade cover is aligned parallel to an imaginary plane of rotation in which the impeller surface rotates (during operation) in the direction of rotation, and / or orthogonally to the base body, with a maximum deviation of + / - 20°, preferably + / - 10°, more preferably + / - 5°, and particularly preferably + / - 2°. Additionally, the blade cover can be aligned parallel to the impeller surface with a maximum deviation of + / - 20°, preferably + / - 10°, more preferably + / - 5°, and particularly preferably + / - 2°. This aspect also contributes to optimizing flow guidance and minimizing turbulence.

[0039] It can also be advantageous if the pump impeller has a direction of rotation and the blade cover projects beyond the base body in the opposite direction of rotation. In this respect, according to the blade geometry of the second type, the conveying channel can be arranged behind the corresponding base body in the direction of rotation, with the surface of the base body adjacent to the conveying channel preferably being the blade suction surface and the opposite side of the base body being a blade pressure surface. This measure also ensures optimized flow guidance and minimized turbulence.

[0040] It can also be advantageous if the blade geometry of the first-type blade and / or the second-type blade has a homogeneous material thickness with a maximum deviation of + / - 30%, preferably + / - 20%, more preferably + / - 10%, and particularly preferably + / - 5%. Optionally, the blade pressure surface and blade suction surface can be parallel. The homogeneous material thickness optimizes the manufacturing process, especially the cooling process during casting. The impeller is preferably made of metal. Due to the blade edge and blade cover described here, it is practically impossible to use a coreless mold anyway, which is why significantly less attention needs to be paid to draft angles, and all surfaces can be optimized for efficiency.

[0041] Furthermore, it can be advantageous to have the same number of buckets of the first type and buckets of the second type. This optimizes the interaction between the different bucket types.

[0042] Furthermore, it is advantageous if the blades of the first type and the blades of the second type are arranged alternately one behind the other in the direction of rotation of the pump impeller. The flow path through two adjacent blades directly influences each other. In this respect, the interaction of the different blade types is optimally utilized.

[0043] Furthermore, it is advantageous if the pump impeller is designed as a free-flow impeller. In this case, the impeller surface is a closed surface, and the axially flowing fluid is deflected radially away from the impeller's axis of rotation. This results in a redirection of the flow path.

[0044] Further features, details and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. The drawings show: Fig. 1 a top view of a pump impeller; Fig. 2 a perspective view of the pump impeller of the Fig. 1 from below; Fig. 3 a perspective view of a pump impeller from above; Fig. 4 a schematic development of a pump impeller; Fig. 5 a perspective view of a housing element; Fig. 6 a cross-section through the housing element of the Fig. 5 Fig. 7 a schematic top view of a housing element with ring-segment-shaped shoulders; Fig. 8 a schematic top view of a housing element with a spiral-shaped shoulder; Fig. 9 a cross-section of a shoulder; Fig. 10 a cross-section of an alternative shoulder; and Fig. 11 a cross-section through a pump.

[0045] After Fig. 1 and Fig. 2A pump impeller 1 has an imaginary axis of rotation DA around which the pump impeller 1 is intended to rotate during operation (hereinafter simply referred to as axis of rotation DA). The axis of rotation DA passes through an impeller hub 14 in the center of an impeller surface 11, the impeller hub 14 having a keyway 15. The impeller hub 14 accommodates a shaft of a pump drive unit. The axis of rotation DA is coaxial with the impeller hub 14. The impeller surface 11 is closed and designed such that a pumped fluid exits the pump impeller 1 radially. The pumped fluid is discharged perpendicular to the axis of rotation DA.

[0046] The pump impeller 1 also has three blades of type 1 2 and three blades of type 2 3, which are arranged on the impeller surface 11. The impeller surface 11 is oriented orthogonally to the axis of rotation DA, and the pump impeller 1 is designed as a free-flow impeller. The impeller surface 11 is closed between blades 2 and 3, so that no fluid can pass through the pump impeller 1 parallel to the axis of rotation DA.

[0047] The pump impeller 1 is rotatable in one direction DR about the axis of rotation DA. This is the preferred direction of rotation DR during operation. The blades of the first type 2 and the blades of the second type 3 are arranged alternately one behind the other in the direction of rotation DR.

[0048] The blades of the first type 2 have a pressure surface 24 and a suction surface 23. The blades of the second type 3 have a pressure surface 34 and a suction surface 35 accordingly. The pressure surfaces 24 each extend convexly in a direction R radially away from the axis of rotation DA. The suction surfaces 23 each extend concavely in the direction R, which corresponds to the radius. This results in a so-called curved blade configuration. Along this path of the blades 2, 3, the pressure surfaces 24 and suction surfaces 23 form circular segments. The blades of the first type 2 and the second type 3 have a homogeneous material thickness 25, 37. Thus, the path of the respective pressure surfaces 24, 34 and suction surfaces 23, 35 is at least substantially parallel.

[0049] The blade geometry of the first type 2 blade differs from the blade geometry of the second type 3 blade.

[0050] The blade geometry of the first type 2 blade has a base body 21 that adjoins the impeller surface 11. The base body 21 runs parallel to the axis of rotation DA and is oriented orthogonally to the impeller surface 11. A blade edge 22 adjoins the base body 21. The blade edge 22 is spaced from the impeller surface 11. A curvature 27 runs between the base body 21 and the blade edge 22. Alternatively, this can be a kink. Due to the curvature 27, the blade edge 22 is inclined at an angle w1 of approximately 70° relative to an imaginary plane of rotation in which the impeller surface 11 rotates (during operation) in the direction of rotation DR. In particular, the angle w1 should be between 55° and 87°, or between 60° and 80°, or between 65° and 75°. Accordingly, the blade edge 22 is inclined at an angle w2 of approximately 20° relative to the base body 11 which is oriented orthogonally to the plane of rotation.Due to the homogeneous material thicknesses 25, 37, the blade pressure surface 24 and the blade suction surface 23 are parallel. Therefore, both the blade pressure surface 24 and the blade suction surface 23 are inclined at angles w1 and w2. Furthermore, the blade edge 22, and with it both the blade pressure surface 24 and the blade suction surface 25, is inclined forward in the direction of rotation DR. The blade edge 22 has a free end 26, in that no further element adjoins the blade edge 22. The base body 21, together with the blade edge 22, forms the blade pressure surface 24 and the blade suction surface 23.

[0051] The second-type bucket 3 comprises a base body 31 and a bucket cover 32. The base body 31 adjoins the impeller surface 11 and is oriented orthogonally to the base body 31. Furthermore, the base body 31 is aligned parallel to the axis of rotation DA. The bucket cover 32 adjoins the base body 31 and is spaced apart from the impeller surface 11. In particular, the bucket cover 32 is aligned parallel to the imaginary plane of rotation in which the impeller surface 11 rotates (during operation) in the direction of rotation DR. A conveying channel 13 thus configured is bounded on three sides by the bucket cover 32, the base body 31, and the impeller surface 11. The bucket cover 32 is also oriented orthogonally to the base body 31 and the axis of rotation DA. The bucket cover 32 is also aligned parallel to the impeller surface 11.The blade cover 32 extends over the base body 31 in the opposite direction of rotation DR, thus extending over the blade suction surface 35.

[0052] The conveying channel 13 is bounded between the suction surface 35 of the base body 31 and the blade cover 32 of the second-type blade 3, as well as the impeller surface 11. A blade channel 12 is formed between blades 2 and 3 adjacent in the direction of rotation DR. Part of the blade channel 12 is formed by the conveying channel 13. The blade channel 12 is partially covered by the blade cover 32 (approximately 25-75%), leaving a gap 16 along the blade channel 12 for fluid inflow. The gap 16 extends over the full length I of the impeller channel 12, with length I running radially to the axis of rotation DA. The blade cover 22 covers the width b of the blade channel 12, with width b extending in the direction of rotation DR. The conveying channel 13 is open at a radially outer impeller edge 17, allowing conveyed fluid to exit the conveying channel 13 in the radial direction R.The impeller edge 17 is located on the outer circumference of the pump impeller 1.

[0053] A in Fig. 3 The pump impeller 1 shown, however, differs from the pump impeller of the Figs. 1 and 2 that this impeller has three impellers of type 1 2 instead of three of type 2. Therefore, the pump impeller 1 has exclusively impellers of type 1 2, specifically six of them.

[0054] The schematic diagram of the Fig. 4 shows a development of a pump impeller 1, where the blade geometries differ from those of the Fig. 3 The difference is that the blade edge 22 does not form a free end 26. Instead, a blade cover 32 adjoins it, which essentially has the same features as the blade cover of the second type 3 blades. Figs. 1 and 2. While the blade edge 22 is inclined forward in the direction of rotation, i.e. in the direction of the blade pressure surface 24, the blade cover 32 projects backward from the end of the blade edge 22 in the direction of rotation, in particular over the blade suction surface 23.

[0055] Another modification of the pump impeller 1 according to the invention can consist in the fact that, in contrast to the illustration of the Figs. 1 and 2It is provided that pairs of a first-type blade 2 and a second-type blade 3 can be provided, wherein a larger blade spacing is formed between the first-type blade 2, equipped with blade edge 22, and the adjacent second-type blade 3, equipped with blade cover 32. In particular, the opening angle between the blade pressure surface 24 of the first-type blade 2 and the blade suction surface 35 of an adjacent second-type blade 3 should be larger than the opening angle between the blade pressure surface 34 of the second-type blade 3 and the blade suction surface 23 of an adjacent first-type blade 2.

[0056] According to Fig. 5 and Fig. 6A housing element 100 is designed as a removable cover, in particular with a mounting flange, for a pump 200. The housing element 100 advantageously has screw holes 107 in the mounting flange. The housing element 100 also has an inner housing wall 103. The inner housing wall 103 has a conical shape extending along a central axis M. The inner housing wall 103 defines a flow channel 105 for a fluid medium that can be conveyed through the flow channel 105 in a main flow direction H. The main flow direction H is coaxial with the central axis M. A fluid inlet opening 104 is provided at the beginning of the main flow direction H. The flow channel 105 widens in the main flow direction H. The surface structure 101 is designed to counteract backflow against the main flow direction H along the inner housing wall 103.

[0057] The surface structure 101 has a flow area 106 that projects transversely into the backflow. The flow area 106 has several steps 102 that form an undercut with respect to the conical inner wall 103 of the housing. The steps 102 are each rotationally symmetrical with respect to the central axis M. In this sense, the step 102 is annular, extending circumferentially U around the central axis M. A total of four steps 102 are provided here, although more or fewer steps 102 can also be provided. The steps 102 are evenly spaced in the main flow direction H and in a radial direction R2. Thus, the steps 102 are parallel to each other. The additional steps 102, the number of which is variable, are also annular.

[0058] As an alternative to the ring-shaped design, paragraphs 102 according to Fig. 7The shoulders 102 can be formed in a ring-segment shape, with the shoulders extending circumferentially U around the central axis M and being evenly spaced in the main flow direction H and the direction R2. Another possibility is to form the shoulder 102 in a spiral shape, wound radially outwards to the central axis M, as shown in [reference to relevant document]. Fig. 8 This shows that with several turns of the spiral, several steps are also created on average, each forming an obstacle to backflow.

[0059] As in Fig. 9 As shown, paragraph 102 has a wedge-shaped cross-section Q. Paragraph 102 can also have a trapezoidal cross-section Q according to the Fig. 10exhibiting. Other alternatives may have a round or oval cross-section. Preferably, however, there are no cross-sectional narrowings in the direction of the main flow direction H due to paragraph 102. Conversely, a stepwise cross-sectional narrowing results in the direction opposite to the main flow direction H.

[0060] A pump 200 according to the invention, which is designed as a free-flow impeller pump, exhibits according to Fig. 11 a pump housing 201. A pump impeller 1 according to the invention is provided in the pump housing 201, as is found, for example, in the Fig. 1, 2 , 3 and 4 The pump impeller 1 is rotatably mounted and is driven by a drive unit 202.

[0061] The fluid medium can be pumped through the pump housing 201 from a pump inlet 203 to a pump outlet 204. The pump inlet 203 and the pump outlet 204 are orthogonal to each other. The pump outlet 204 extends radially from the pump impeller 1 out of an impeller chamber 206, in which the pump impeller 1 is located.

[0062] The pump housing 201 comprises a housing element 100 according to the invention. The housing element 100 forms a wall of the impeller chamber 206. The pump impeller 1 is arranged in the main flow direction H relative to the housing element 100, with its central axis M being parallel and coaxial with the axis of rotation DA. The fluid inlet opening 104 of the housing element 100 is located in the region of the pump inlet 203. The flow channel 105 is arranged between the pump inlet 203 and the pump impeller 1. A free space 207 is formed in the flow channel 105 and between the pump inlet 203 and the pump impeller 1, in which no further flow-guiding elements are provided. A vortex forms in this space 207 because the fluid is set into rotation by the pump impeller 1. An overpressure at the pump outlet 204 then leads to a backflow on the inner wall of the housing element 100.The steps here create flow obstacles for the backflow and direct the backflow back into the main flow direction H.

[0063] Alternatively, the housing element 100 can be designed as a removable cover with a mounting flange and attached to the rest of the pump housing 201 by means of screws as fastening means.

[0064] Another alternative is to insert the housing element 100 into the interior of the pump housing 101. For this to work, the pump housing 101 should have a recess for the housing element. Reference symbol list

[0065] 1 Pump impeller 11 Impeller surface 12 Blade channel 13 Conveyor channel 14 Impeller hub 15 Keyway 16 Gap 17 Blade edge 2Bucket of the first type 21Base body 22Bucket edge 23Bucket suction surface 24Bucket pressure surface 25Material thickness 26Free end 27Curvature 3 Second type bucket 31 Base body 32 Bucket cover 34 Bucket pressure surface 35 Bucket suction surface 37 Material thickness 100 Housing element 101 Surface structure 102 Heel, shoulder, step 103 Inner wall of housing 104 Fluid inlet opening 105 Flow channel 106 Inlet surface 200 Pump 201 Pump housing 202 Drive unit 203 Pump inlet 204 Pump outlet 206 Impeller chamber 207 Free space b Width of the blade channel I Length of the blade channel DR Direction of rotation DA Axis of rotation H Main flow direction R Direction radial to the axis of rotation R2 radial direction M Central axis Q Cross-sectional profile U Circumferential direction w1 Angle w2 Angle

Claims

1. Vortex impeller pump (200) with a pump housing (201) in which a pump impeller (1) designed as a vortex impeller is rotatably mounted, by way of which impeller a fluid medium is able to be conveyed from a pump inlet (203) of the pump housing (201) to a pump outlet (204) of the pump housing (201), wherein the pump housing (201) has a housing element (100) with a housing inner wall (103) which delimits a flow channel (105) for a fluid medium extending along a central axis (M), wherein the cross section of the flow channel (105) increases in a main flow direction (H), wherein the flow channel (105) of the housing element (100) is arranged between the pump inlet (203) and the pump impeller (1), wherein the housing element (100) forms a wall of a pump hydraulics and the pump impeller (1) is arranged in an impeller chamber (206) of the pump hydraulics, characterized in that formed between the housing element (100) and the pump impeller (1) within the impeller chamber (206) is a void without further flow guide elements, wherein the housing inner wall (103) has a surface structure (101) which is designed in such a manner that it counteracts a return flow counter to the main flow direction (H) along the housing inner wall (103) of the fluid medium, wherein the pump impeller (1) is arranged in the direction of the main flow direction (H) opposite the surface structure (101) of the housing element (100), wherein the void is designed in such a manner that a spiral-shaped fluid swirl is formed between the pump inlet (203), the latter formed by the housing element (100), and the pump impeller (1), which causes a return flow along the housing inner wall (103) of the housing element (100) that subsequently collides with the surface structure (101) and swirls.

2. Vortex impeller pump (200) according to Claim 1, characterized in that the surface structure (101) of the housing element (100) has at least one inflow surface which protrudes transversely into the return flow.

3. Vortex impeller pump (200) according to one of Claims 1 and 2, characterized in that the surface structure (101) of the housing element (100) has at least one shoulder (102).

4. Vortex impeller pump (200) according to Claim 3, characterized in that the shoulder (102) protrudes transversely into the return flow.

5. Vortex impeller pump (200) according to one of Claims 3 and 4, characterized in that the shoulder (102) is formed with an undercut, in particular in such a manner that the return flow flows at least slightly underneath the shoulder (102).

6. Vortex impeller pump (200) according to one of Claims 3 to 5, characterized in that the shoulder (102) has a wedge-shaped or trapezoidal cross-sectional profile.

7. Vortex impeller pump (100) according to one of Claims 3 to 6, characterized in that the shoulder (102) is of a rotationally symmetrical design.

8. Vortex impeller pump (200) according to one of Claims 3 to 7, characterized in that the surface structure (101) has at least one or two or three further shoulders (102), wherein the shoulders (102) are mutually spaced apart in terms of a direction radial to the central axis (M) and / or the main flow direction (H).

9. Vortex impeller pump (200) according to Claim 8, characterized in that no tapers in the main flow direction (H) are formed between a plurality of shoulders (102) in the flow channel (105).

10. Vortex impeller pump (200) according to one of Claims 3 to 9, characterized in that the at least one shoulder (102) is configured in an annular or annular segment-shaped manner.

11. Vortex impeller pump (200) according to one of Claims 3 to 7, characterized in that the shoulder (102) is configured to be spiral-shaped and preferably is wound radially outwardly starting from the central axis (M).

12. Vortex impeller pump (100) according to one of Claims 3 to 11, characterized in that the shoulder (102) is designed in a step-like manner, wherein the step is characterized in particular in that the step is passed downwards in the main flow direction (H) and upwards counter to the main flow direction (H).

13. Vortex impeller pump (200) according to one of the preceding claims, characterized in that the housing inner wall (103) has a conical basic shape on which the surface structure (101) is formed, wherein the housing inner wall (103) widens in the main flow direction (H).

14. Vortex impeller pump (200) according to one of the preceding claims, characterized in that the housing element (100) is designed as a releasable cover of the pump housing (201) and / or the housing element (100) forms the impeller chamber (206) of the pump housing (201) and / or the housing element (100) is an insert element in the impeller chamber (206) of the pump housing (201).

15. Vortex impeller pump (200) according to one of the preceding claims, characterized in that the pump impeller (1) has an impeller surface (11) and a direction of rotation (DR), wherein blades (2, 3) are arranged on the impeller surface (11), wherein at least one of the blades (2, 3) is a first type of blade (2), and where the blade geometry of the first type of blade (2) has a blade edge (22) tilted forwards in the direction of rotation (DR).