Pump assembly

Abstract

The invention relates to a pump assembly, having an intake opening 5 for sucking a flow medium into a flow chamber 6, a discharge opening 7 for discharging the flow medium out of the flow chamber 6, an impeller shaft 18 which can rotate about a rotational axis A and extends into the flow chamber 6, and an impeller mounted on an end 19 of the impeller shaft 18 located within the flow chamber 6, which impeller is designed as a channel impeller with a cover plate 22 forming a suction mouth 24, a support plate 21 with a hub area 26 and at least one vane 23 arranged between the cover plate 22 and the support plate 21. According to the invention, a wiper finger 43 of a solids wiper device 35 extends in the axial direction through the intake opening 5 and the suction mouth 24 to the vicinity of the hub area 26 of the impeller 20.

Description

[0001] The invention relates to a pump arrangement for pumping waste water, comprising an inlet opening for sucking in a pumping medium into a flow chamber, an outlet opening for expelling the pumping medium from the flow chamber, an impeller shaft rotatable about an axis of rotation and extending into the flow chamber, and an impeller fastened to an end of the impeller shaft located within the flow chamber, which impeller is designed as a channel impeller with a cover disc forming a suction mouth, a support disc with a hub region, and at least one blade arranged between the cover disc and the support disc.

[0002] Pump arrangements of the type described above are used in a variety of ways. Channel impellers, especially closed channel impellers, are characterized by particularly good hydraulic efficiency, but depending on their size, they are not suitable for raw sewage, or only to a limited extent. Due to a reduction in wastewater due to general water conservation, and at the same time a growing accumulation of wastewater with components that tend to clog, such as rags, nonwovens, or similar, the risk of clogging in such a pump arrangement increases. During long-term operation, this leads to increasingly large accumulations of solids, which cause an increase in power consumption, a decrease in discharge head and flow rate, and an increase in vibrations. In particular, the solids accumulate at the blade leading edges or the hub, where they maintain a very stable position.

[0003] US 1,182,439 A describes a channel impeller for a wastewater pump with double-walled and rounded blades on which the solids contained in the pumped medium can slide off.

[0004] From JP S53 57507 A a submersible pump with a free-flow impeller is known, in which a cutting element for crushing solids interacts with the hub.

[0005] US 2003 / 215331 A1 describes a device which is attached to the pump housing for scraping off contaminants on the leading edges and for feeding them to the circumference in the region of a groove in the pump housing wall, wherein the device has a flat surface which points towards the leading edge and is parallel thereto and is located at a distance of 0.05 to 1 mm from the edge.

[0006] GB 1 551 918 A discusses a centrifugal pump having a closed impeller, the impeller having an inlet in a region radially inward of the circumference of the impeller and the pump having a scraper rotatable relative to the impeller near the edges of the impeller blades at the inlet to remove solid material fouling those edges.

[0007] DE 240 859 C discloses a centrifugal pump in which at least one fixed part is provided near the point of entry of the conveyed material into the impeller blades, which prevents entrained flexible bodies from becoming stuck at the point of entry of the impeller blades

[0008] GB 812 371 A shows a centrifugal pump for pumping liquids which may contain fibrous material, wherein an arm is provided which projects continuously into the eye of the impeller and is arranged adjacent to the leading edges of the blades, the arrangement being such that when the impeller is rotated, a relative movement is caused between the blades and the arm.

[0009] The object of the invention is to provide a pump arrangement for pumping waste water which is characterized by particularly good hydraulic efficiencies.

[0010] The object of the invention is achieved by a pump arrangement according to claim 1.

[0011] According to the invention, a scraper finger of a solid scraper device extends in the axial direction through the inlet opening and the suction mouth to close to the hub area of ​​the impeller.

[0012] This makes it possible to simultaneously protect the blade leading edge or, in the case of multiple blades, the blade leading edges, the hub of the impeller and the fastening means for attaching the impeller to the shaft from solid debris.

[0013] For easy assembly, in a preferred embodiment the solids scraper device has a mounting flange for attaching the solids scraper device to the pump assembly.

[0014] An advantageous embodiment provides that the fastening flange has a region which has a first recess in the axial direction and a second recess in the radial direction.

[0015] According to the invention, the stripping finger which can be inserted into the first and second recess has a substantially L-shaped design with a short leg and a long leg.

[0016] In order to prevent the fibrous solids in the raw sewage from settling on the inlet edge or the hub when entering the suction mouth of the pump and instead to be stripped off the inlet edge or the hub and pumped further, the side of the long leg facing away from the axis of rotation advantageously has a contour along a section extending essentially into the suction mouth of the impeller, which is adapted to the contours of the inner diameter of the inlet opening and the inner diameter of the suction mouth of the impeller.

[0017] Further along the length, i.e., essentially in the axial direction of the impeller's support disk, the side of the long leg facing away from the axis of rotation advantageously has a contour along a section extending essentially to the hub area of ​​the impeller. This contour corresponds to the contour of a leading edge of at least one blade of the impeller, maintaining a defined distance, when the leading edge moves along the section due to the rotation of the impeller. The leading edge essentially forms a type of rotating body that rotates over the wiper finger.

[0018] According to the invention, along an arcuate section extending initially in the direction of the inlet opening and then in the direction of the axis of rotation, the side of the long leg facing away from the inlet opening has a contour profile which corresponds to the contour of the hub area and a part of the screw head of a screw for fastening the impeller to the impeller shaft while maintaining a defined distance.

[0019] Ideally, the side of the long leg facing away from the inlet opening has a contour along a section extending essentially in the radial direction beyond the axis of rotation, which contour is adapted to the contour of the screw head of the screw while maintaining a defined distance.

[0020] According to the invention, a projection is provided at a free end of the long leg, which is arranged concentrically to the axis of rotation and extends into a recess in the screw head. Ideally, the projection has a circular-cylindrical shape. If, during operation, solids cause severe bending stress on the stripping finger during the stripping process, the deflector finger rests on the projection in a recess in the screw head, thus preventing permanent bending of the leg.

[0021] Embodiments of the invention are illustrated in the drawings and are described in more detail below. Fig. 1 shows a longitudinal section through a pump arrangement with a solid scraper device according to the invention, Fig. 2 shows a detailed section of the Fig. 1 Fig. 3a a section through a mounting flange of the solid scraper device according to the Fig. 1 , Fig. 3bthe mounting flange according to Fig. 3a in plan view, Fig. 4 a longitudinal section through a scraper finger of the solid scraper device according to the Fig. 1 , Fig. 5 a plan view of the free end of the stripping finger according to the Fig. 4 , Fig. 6 the longitudinal section through the Fig. 1 shown pump arrangement with a further embodiment of the solid scraping device according to the invention, Fig. 7 the longitudinal section through the Fig. 1 shown pump arrangement with a further embodiment of the solids stripping device according to the invention, and Fig. 8 a further embodiment of the solids stripping device according to the invention

[0022] The Fig. 1 combined with Fig. 2 shows a pump assembly 1, which can usually be installed horizontally in a pump sump, in the form of a canned motor pump with a pump part and an electrical part. The pump part of the pump assembly 1 has a multi-part pump housing 2 of a centrifugal pump, which comprises a hydraulic housing 3 designed as a spiral housing and a housing cover 4.

[0023] The hydraulic housing 3 has an inlet opening 5 for sucking a pumping medium into a flow chamber 6 and an outlet opening 7 for expelling the pumping medium from the flow chamber 6. A recess 8 is provided in the inlet opening 5, in which a split ring 9 is received. The housing cover 4 is arranged on the side of the hydraulic housing 3 opposite the inlet opening 5 and has a through-opening 10. On the side of the housing cover 4 facing away from the flow chamber 6, a bearing support unit 11 is arranged, which is fastened to the hydraulic housing 3 by suitable means (not shown), for example threaded bolts or screws. On the side of the bearing support unit 11 facing away from the housing cover 4, a housing element 12 is fastened, in which the majority of the motor components, e.g. devices for receiving the stator windings and devices for receiving the rotor windings, are arranged.

[0024] The bearing support unit 11 has a through-opening 13 in which a rolling bearing 14 is arranged. The housing element 12 has an inner wall 15 with a holding device 16. Another rolling bearing 17 is arranged in the holding device 16. The two rolling bearings 14 and 17 support an impeller shaft 18 that is rotatable about a rotational axis A and extends through the housing element 12, the through-opening 13 of the bearing support unit 11, and the through-opening 10 of the housing cover 4 into the flow chamber 6.

[0025] An impeller 20 in the form of a closed channel impeller is attached to an end 19 of the impeller shaft 18 located within the flow chamber 6. The impeller 20 comprises a support disk 21 on the side facing the housing cover 4. A cover disk 22 is arranged at a distance from the support disk 21 in the direction of the inlet opening 5 by means of at least one impeller blade 23. The cover disk 22 forms a circular suction mouth 24 facing the inlet opening 5, in particular the split ring 9. The at least one impeller blade 23 has an inlet edge 25. In the Fig. 1 Two impeller blades 23 are shown, depending on the size, for example, 3 or more impeller blades can be provided.

[0026] In the Fig. 1 or Fig. 2 In the embodiment shown, the end 19 of the impeller shaft 18 is conical and tapers towards the inlet opening 5. The support disk 21 of the impeller 20 is provided with a hub region 26 having a conical bore 27 corresponding to the end 19. The bore 27 has a cylindrical section 28 with a reduced inner diameter, which can serve as a stop shoulder when the impeller 20 is pushed onto the impeller shaft 18.

[0027] At the end 19 of the impeller shaft 18, a threaded bore 29 is provided on the front side, into which a screw 30 can be screwed and securely fixes the impeller 20 to the impeller shaft 18. The screw 30 has a screw head 31. The screw head 31 rests against the section 28 with a reduced inner diameter and is provided with a recess 32, which in the illustrated embodiment is designed as a hexagon socket, by means of which the screw 30 can be screwed into or out of the threaded bore 29 using a suitable tool. The section 28 is provided with an internal thread 33, which is not operatively connected to the screw 30, but is intended for a removal tool (not shown) for releasing the impeller 20 from the impeller shaft 18.

[0028] At the inlet opening 5, the hydraulic housing 3 has a flange 34 on which a solids scraper device 35 is arranged. The solids scraper device 35 has a mounting flange 36 that can be attached to the flange 34.

[0029] The Fig. 3a und 3b show the mounting flange 36 in detail, with the Fig. 3a a section along the line BB from the Fig. 3b shows.

[0030] The fastening flange 36 is designed as an annular disk and has a plurality of through holes 37 through which screws (not shown) can be passed. The screws can be screwed into threaded holes (not shown) in the flange 34 of the hydraulic housing 3, whereby the fastening flange 36 can be securely fastened to the hydraulic housing 3. The fastening flange 36 has a region 38 which has a first recess 39 in the axial direction and a second recess 40 in the radial direction. In the region 38, in particular in the axial recess 39, at least one blind hole 41 is provided, which is provided with an internal thread 42. In the embodiment shown, three blind holes 41 are formed.

[0031] The solid scraper device 35 has a scraper finger 43 which can be attached to the fastening flange 36 and which is inserted into the Fig. 4 und 5 The stripping finger 43 has a substantially L-shaped design with a short leg 44 and a long leg 45. As the Fig. 2 As can be seen, in the installed state the short leg 44 extends essentially in a radial direction, while the long leg 45 extends essentially parallel to the axis of rotation A.

[0032] The short leg 44 of the stripping finger 43 has, as detailed in Fig. 4 shown, at least one through-hole 46 with a first section 47 of enlarged inner diameter and a second section 48 of reduced inner diameter, forming a shoulder 49. In the illustrated embodiment, the short leg 44 has three through-holes 46. Through the through-holes 46, the Fig. 2 shown screws 50. The screws 50 can be screwed into the internal threads 42 formed in the mounting flange 36, with the screw heads resting on the shoulder 49, whereby the stripping finger 43 can be securely attached to the mounting flange 36.

[0033] The long leg 45 is essentially divided into five sections 51, 52, 53, 54 and 55. The section 51 extends essentially from the intersection point of the two legs 44 and 45 in the axial direction through the Fig. 1 and 2shown fastening flange 36. This is followed by section 52, which extends essentially into the suction mouth, in particular up to the transition from the cover plate 22 to the at least one impeller blade 23. Section 51 and section 52 extend essentially parallel to the axis of rotation A. Section 53 adjoins section 52 and then extends essentially up to the hub region 26 of the impeller 20. Section 53 extends in the axial direction and in doing so approaches the axis of rotation A. The extension in the axial direction along the axis of rotation is preferably greater than the extension in the radial direction, i.e. in the direction of the axis of rotation, and depends on the design of the impeller 20. Close to the hub region, section 53 has a convex shape. A small distance is maintained such that the rotating hub area 26 does not come into contact with the stationary scraper finger 43.Section 54, which adjoins section 53, initially extends toward inlet opening 5 and then further toward rotation axis A. It is curved, particularly concave. Section 55 then extends essentially radially beyond rotation axis A.

[0034] The side of the leg 45 facing away from the rotational axis A has a contour 56 along the section 52, which is adapted to the contours of the inner diameter of the inlet opening 5 and the split ring 9 in the hydraulic housing 3 as well as the inner diameter of the suction mouth 24 of the impeller 20. In this case, a small, Fig. 2 shown distance W between the opposing surfaces of the rotating component, in particular in the suction mouth 24, and the fixed scraper finger 43 is provided such that the opposing surfaces do not touch during operation.

[0035] Furthermore, the side of the leg 45 facing away from the axis of rotation A has a contour profile 57 along the section 53, which corresponds to the contour of the leading edge 25 of the at least one blade 23 of the impeller 20 while maintaining a defined, in the Fig. 2 corresponds to the distance X shown when the leading edge 25 moves along the section 53 due to the rotation of the impeller 20. This means that the leading edge 25 forms a surface of rotation due to the rotation of the impeller 20, which rotates past the side of the scraper finger 43 facing the leading edge 25 at the distance X.

[0036] The selected distance X is in a range of 0.1 mm to 0.6 mm and preferably at a distance of 0.3 mm.

[0037] Along the curved section 54, the side of the leg 45 facing away from the inlet opening 5 has a contour 58 which coincides with the contour of the hub area 26 and a part of the screw head 31 of the screw 30 while maintaining a defined Fig. 2 shown distance Y corresponds.

[0038] The side of the leg 45 facing away from the inlet opening 5 has a contour 59 along the section 55, which is adapted to the contour of the screw head 31 of the screw 30 while maintaining a defined Fig. 2 shown distance Z.

[0039] In the section 55, a projection 61 is provided at a free end 60 of the leg 45. The projection 61 has, as shown in the Fig. 5 As can be seen, it has a circular cylindrical shape. Fig. 1 and 2As can be seen, in the installed state the projection 61 is arranged concentrically to the axis of rotation A. The projection 61 extends into the recess 32 of the screw head 31. If, during operation, solids lead to a strong bending load on the stripping finger 43 during the stripping process, the deflector finger 43 is supported by the projection 61 in the recess 32, thereby preventing permanent bending of the leg 45.

[0040] At the Fig. 6 The screw 30 has a screw head 31 with an external hexagon 62. The recess 32 is formed as a circular cylindrical blind hole. The contour of sections 54 and 55 of the stripping finger 43 is accordingly adapted to the contour of the screw head 30.

[0041] At the Fig. 7 the side opposite the section 53 of the stripping finger 43 is essentially formed as a straight line 63.

[0042] The Fig. 8 shows a further embodiment of the solid scraper device 35. The fastening flange 36 and scraper finger 43 are formed in one piece.

[0043] It is understood that the Fig. 1 bis 7 The stripping finger 43 shown can be formed integrally with the fastening flange 36.

Claims

1. Pump arrangement for delivery of wastewater, having - an inlet opening (5) for intake of a delivery medium into a flow chamber (6), - an outlet opening (7) for expulsion of the delivery medium from the flow chamber (6), - an impeller shaft (18), which is rotatable about an axis of rotation (A) and extends into the flow chamber (6), and - an impeller (20), which is fastened to an end (19), situated within the flow chamber (6), of the impeller shaft (18) and is in the form of a channel impeller with a cover shroud (22) which forms a suction mouth (24), with a rear shroud (21) which has a hub region (26), and with at least one blade (23) which is arranged between the cover shroud (22) and the rear shroud (21), characterized in that a stationary stripper finger (43) of a solids stripper device (35) extends in an axial direction through the inlet opening (5) and the suction mouth (24) as far as a point close to the hub region (26) of the impeller (20), wherein the stripper finger (43) has a substantially L-shaped design with a short limb (44) and with a long limb (45), wherein that side of the long limb (45) directed away from the inlet opening (5) has, along a portion (54) extending firstly in the direction of the inlet opening (5) and over the further course in the direction to the axis of rotation (A), a contour profile (58) which, with a defined spacing (Y) being maintained, corresponds to the contour of the hub region (26) and of a part of a screw head (31) of a screw (30) for fastening the impeller (20) to the impeller shaft (18), and, at a free end (60) of the long limb (45), there is provided a projection (61) which is arranged concentrically with respect to the axis of rotation (A) and which extends into a depression (32) of the screw head (31).

2. Pump arrangement according to Claim 1, characterized in that the solids stripper device (35) has a fastening flange (36) for fastening the solids stripper device (35) to the pump arrangement.

3. Pump arrangement according to Claim 2, characterized in that the fastening flange (36) has a region (38) having a first recess (39) in an axial direction and having a second recess (40) in a radial direction.

4. Pump arrangement according to one of Claims 1 to 3, characterized in that that side of the long limb (45) directed away from the axis of rotation (A) has, along a portion (52) extending substantially as far as the suction mouth (24) of the impeller (20), a contour profile (56) which is matched to the contours of the inner diameter of the inlet opening (5) and of the inner diameter of the suction mouth (24) of the impeller (20).

5. Pump arrangement according to one of Claims 1 to 4, characterized in that that side of the long limb (45) directed away from the axis of rotation (A) has, along a portion (53) extending substantially as far as the hub region (26) of the impeller (20), a contour profile (57) which, with a defined spacing (X) being maintained, corresponds to the contour of an inlet edge (25) of the at least one blade (23) of the impeller (20) when the inlet edge (25), by way of rotation of the impeller (20), moves along the portion (53).

6. Pump arrangement according to one of Claims 1 to 5, characterized in that that side of the long limb (45) directed away from the inlet opening (5) has, along a portion (55) extending substantially in a radial direction across the axis of rotation (A), a contour profile (59) which, with a defined spacing (Z) being maintained, is matched to the contour of the screw head (31) of the screw (30).

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