Centrifugal pump assembly

Abstract

The invention relates to a centrifugal pump assembly (1) comprising a housing (2), an inlet opening (3), an outlet opening (4), and an open impeller (5) with a hub (7) supporting at least one blade (8). The blade (8) has a leading edge (15), an exit edge (16), a suction-side surface (17), a pressure-side surface (18), and an outer edge (11) extending along an inner wall (10) of the housing (2). The blade (8) has a wall (13) along a defined region (14) of the outer edge (11) to reduce shear forces.

Description

[0001] The invention relates to a centrifugal pump arrangement with a housing, an inlet opening, an outlet opening and an open impeller with a hub that carries at least one blade, wherein the blade has an inlet edge, an outlet edge, a suction-side surface, a pressure-side surface and an outer edge extending along an inner wall of the housing.

[0002] A tubular casing pump is a centrifugal pump whose pumped medium, after passing through the impeller and the guide vane mounted on the casing, flows through the tubular pump housing. The most common tubular casing pumps are vertical pumps. In wet installations, their inlet nozzle is immersed in an open or covered inlet chamber; in dry installations, their suction end is screwed to an inlet elbow or sealed to the ceiling of an inlet chamber.

[0003] Depending on the specific rotational speed, the impeller is either a axial or semi-axial impeller. The guide vane opens into the riser pipe, and depending on the installation depth, several riser pipes can be arranged in series. This also lengthens the pump shaft accordingly, requiring multiple bearings. The subsequent discharge elbow then directs the flow from the riser pipe to the outlet or the pump discharge port. The shaft exits the pipe housing at the discharge elbow via a stuffing box or a mechanical seal.

[0004] A centrifugal pump in the form of a pipe casing pump is often used in pumping stations. These are also called pumping stations and serve for the irrigation or drainage of rural areas.

[0005] In coastal areas protected by dikes and located below high tide levels, drainage is essential. Typically, several smaller pumping stations, scattered throughout a catchment area, supply a larger main pumping station. If natural drainage through the sluice gate (a closable opening in the dike) is no longer possible due to high water levels, the pipe pump is activated.

[0006] EP 1 597 483 B1 discloses a tubular casing pump whose impeller and guide assembly is connected to a riser pipe, wherein a shaft arranged inside the riser pipe, driving the impeller, is connected to a drive arranged above the riser pipe, a multi-part lantern transfers the weight of the drive to a foundation, an external bearing element known per se is provided on the riser pipe and / or the elbow, and the riser pipe opens into a pressure-tight elbow housing. A force-transmitting receptacle, guide, and seal for the external bearing element is provided in a base plate of a pressure-tight elbow housing.

[0007] EP 2 295 808 B1 discloses a pump or turbine device comprising a tubular casing with an inlet opening and an outlet opening and a driven helical impeller with a hub carrying at least one blade; wherein the impeller is arranged coaxially with a guide vane attached to the inner wall of the tubular casing by means of guide vanes, wherein the guide vanes have an inclined end forming an inlet angle Y with the axis of rotation A, the inclined end of each guide vane extending at an angle of less than 45° with respect to the axis of rotation.

[0008] Centrifugal pumps used for draining land areas are frequently swum through by aquatic life, such as fish, even when the pump is in operation. This is often critical, even life-threatening, for these creatures. The underlying assumption is that the centrifugal forces of the pump press fish against the wear ring and / or the pump housing. This can lead to scraping collisions between the fish and the housing wall or the wear ring.

[0009] The object of the invention is to provide a centrifugal pump assembly that exhibits only low shear forces between moving and stationary components. The centrifugal pump should be capable of achieving a high flow rate and meet the requirements of nature and animal protection. Furthermore, the centrifugal pump should fulfill the requirements of being a fish-friendly pump. The design of the centrifugal pump assembly should facilitate the replacement of spare parts. The centrifugal pump assembly should be simple and cost-effective to implement.

[0010] This problem is solved according to the invention by a centrifugal pump arrangement with a housing according to the features of claim 1. Preferred variants can be found in the dependent claims, the subclaims, the description and the drawings.

[0011] According to the invention, the shovel has a wall along a defined area of ​​the outer edge to reduce shear forces.

[0012] For example, the wheel is designed as an axial wheel or as a semi-axial wheel and is also referred to as a helical or diagonal wheel.

[0013] For example, the impeller includes one or more blades.

[0014] In one variant of the invention, the wall is designed as a wiper or deflector, thereby significantly reducing the contact area with the wear ring or the housing.

[0015] In another embodiment of the invention, the wall is designed as a projection of the blade at a point on the outer edge relative to the housing. Previously, blades were always designed to be almost flush with the housing at the outer edge, which could result in high shear forces acting in this area. The wall, particularly in its projection configuration, significantly reduces these shear forces.

[0016] For example, the wall is designed as a kink in the blade, which means that the blade is extended by a "kinked ear" at least in one area towards the outer edge. The kink in the blade significantly reduces the shear forces at the contact surface with the housing.

[0017] In one variant of the invention, the wall is designed as an angle along a region of the outer edge of the blade to reduce shear forces.

[0018] In a further embodiment of the invention, the wall is shaped like a wing, at least in one area at the outer edge of the bucket, thereby forming a sliding channel for solids. Due to this sliding channel, which is partially bounded by the wing, significantly lower shear forces act on the conveyed medium and any solids or living organisms contained therein at the outer edge.

[0019] If the pumped medium contains solids and / or living organisms, the advantageous wall of the impeller reduces shear forces, resulting in less wear on the pump and allowing living organisms, such as fish, to be pumped without physical harm.

[0020] For example, the wall is located on the pressure-side surface of the blade.

[0021] In an alternative version of the invention, the wall is arranged on the suction-side surface of the shovel.

[0022] In another variant of the invention, the wall is arranged on both the suction and pressure side surfaces of the blade.

[0023] For example, the area where the wall is located at the outer edge extends to the exit edge, so that the sliding channel for living beings is formed up to the outlet from the wheel.

[0024] In one variant of the invention, the area along the outer edge, in which the wall is arranged at the outer edge, extends over more than 30% of the length of the outer edge of the shovel.

[0025] In another variant of the invention, the area begins more than 30% of the blade length behind the leading edge.

[0026] In a preferred embodiment of the invention, the area extends to the exit edge of the shovel.

[0027] The area preferably extends from approximately the middle of the shovel to the exit edge.

[0028] Preferably, the area begins essentially between a free end of the shovel and near its center and extends to the exit edge.

[0029] For example, the wall along the outer edge of the shovel has a height of more than 30% of the shovel's thickness in the outer edge area. This allows the wall to be particularly thin and material-efficient, yet still well-defined and stable.

[0030] In one embodiment of the invention, the wall has an average height of more than 30% and / or less than 100% of the maximum thickness of the blade in the region of the outer edge. The thickness of the blade can vary along its length due to flow-optimized design.

[0031] For example, the height of the wall is almost identical and unchanged over the length of the area; preferably, the height of the wall is constant over the length of the area.

[0032] In one variant of the invention, the transition between the blade surface and the wall is rounded. This significantly reduces the shear forces that can act on living organisms.

[0033] Preferably, the centrifugal pump assembly includes a guide device. The wall on the outer edge of the impeller and the arrangement of the guide device within the centrifugal pump form a sliding channel that reduces shear forces, facilitating the transport of living organisms through the centrifugal pump.

[0034] In one embodiment of the invention, the housing extends conically from the inlet opening of the centrifugal pump, i.e., the inner diameter increases axially from the inlet opening. The impeller is adapted to this conical shape, in particular the shape of the blades and the shape of the wall.

[0035] Preferably, the outer edge of the blade and the inner wall of the housing are aligned parallel to each other to form a thin gap. Similarly, the wall at the outer edge is also aligned parallel to the inner wall of the housing.

[0036] According to the invention, the centrifugal pump arrangement is used as a fish-friendly pump to reduce shear forces acting on the fish between the impeller and the housing.

[0037] Centrifugal pumps, in their various configurations as either in-line or submersible pumps, achieve a high flow rate at a delivery head of 3–5 m, typically used in pumping stations for draining rural areas. An open impeller interacts with the wear plate or wear ring of the pump casing. An advantageous impeller design with blades featuring a wall allows for the formation of a scraper channel. This scraper channel prevents fish from rubbing against the wear plate and reduces shear velocity.

[0038] In a blade configuration, the wall at the outer edge of the blade can extend from the height of the hub, i.e., from the blade tip along the running surface to the blade trailing edge. In an advantageous variant, the wall height is approximately 10% to more than 100% of the average impeller thickness.

[0039] The inventive design of a centrifugal pump assembly with an open impeller including at least one walled blade can be implemented cost-effectively, for example, using a forming or additive manufacturing process. Assembly and replacement of spare parts are particularly simple and user-friendly.

[0040] Further features and advantages of the invention will become apparent from the description of exemplary embodiments with reference to the drawings and from the drawings themselves.

[0041] This shows: Fig. 1 a sectional view through a tubular casing pump, Fig. 2 a perspective view of the impeller from the side, Fig. 3 another perspective view of the impeller looking at the outer edge of a blade, Fig. 4 a perspective view of the impeller from above.

[0042] Fig. 1 Figure 1 shows a centrifugal pump arrangement 1 with a casing 2 having an inlet opening 3, an outlet opening 4, and a driveable, helical impeller 5, which can be driven by means of a shaft 6 to rotate about a rotary axis A. The casing 2 extends conically from the inlet opening 3, i.e., it widens in the direction of flow.

[0043] The impeller 5 comprises a conical hub 7 which carries two blades 8. Above the impeller 5 is a guide device 9, which is arranged on an inner wall 10 of the housing 2.

[0044] The blade 8 has an outer edge 11 that extends along the inner wall 10 of the housing 2. The outer edge 11 and the inner wall 10 of the housing 2 are aligned parallel to form a gap, indicated by the reference numeral 12. The blade 8 has a wall 13 along a defined area 14 of the outer edge 11 to reduce shear forces.

[0045] In Fig. 2 , Fig. 3 and Fig. 4 Each figure shows a perspective view of the impeller 5. The blade 8 has a leading edge 15, an exit edge 16, a suction-side surface 17, a pressure-side surface 18, and the outer edge 11.

[0046] The area 14 of the outer edge 11 extends approximately from the middle of the shovel 8 to the exit edge 16. In In the illustrated version, area 14 extends over 48% of the outer edge 11.

[0047] The wall 13 in the area 14 of the outer edge 11 has an average height H of 40% of the maximum thickness D of the shovel 8.

[0048] The wall 13 is arranged on the pressure-side surface 18 and in this embodiment has a height of 35% of the thickness of the blade 8 in the area 14 of the outer edge 11.

[0049] In the illustrated embodiment, the wall 13 has the shape of a wing at the outer edge 11 of the bucket 8. This forms a sliding channel for solids. Due to this sliding channel, which is partially bounded by the wall 13, significantly lower shear forces act on the conveyed medium and any fish contained therein at the outer edge 11.

[0050] Fig. 4 Figure 5 shows a perspective view of the impeller 5. A rounded transition 19 is formed from the pressure-side blade surface 16 to the wall 11. This advantageously reduces the shear forces that can act on living organisms.

[0051] From the Fig. 1 bis 4 It is evident that the area 14 extends essentially between a free end 20 of the bucket 8 and near its center to the exit edge 14.

Claims

1. Centrifugal pump assembly (1) comprising a casing (2), an inlet opening (3), an outlet opening (4) and an open impeller (5) with a hub (7) supporting at least one blade (8), wherein the blade (8) has a leading edge (15), an exit edge (16), a suction-side surface (17), a pressure-side surface (18) and an outer edge (11) extending along an inner wall (10) of the casing (2), characterized by that the shovel (8) has a wall (13) along a defined area (14) of the outer edge (11) to reduce shear forces.

2. Centrifugal pump arrangement according to claim 1, characterized by the fact that the wall (13) is arranged on or at the pressure-side surface (18).

3. Centrifugal pump arrangement according to claim 1 or 2, characterized by the fact that the wall (13) is arranged on or at the suction-side surface (17).

4. Centrifugal pump arrangement according to one of claims 1 to 3, characterized by the fact thatthe defined area (14) extends to the exit edge (16).

5. Centrifugal pump arrangement according to one of claims 1 to 4, characterized by the fact that the area (14) extends over more than 30% along the outer edge (11).

6. Centrifugal pump arrangement according to one of claims 1 to 5, characterized by the fact that the wall (13) has an average height (H) of more than 30% and / or less than 100% of the maximum thickness (D) of the blade (8) in the defined area (14) of the outer edge (11).

7. Centrifugal pump arrangement according to one of claims 1 to 6, characterized by the fact that the centrifugal pump arrangement (1) comprises a guide device (9).

8. Centrifugal pump arrangement according to one of claims 1 to 7, characterized by the fact that the housing (2) extends conically from the inlet opening (3).

9. Centrifugal pump arrangement according to one of claims 1 to 8, characterized by the fact thatthe outer edge (11) and the inner wall (10) of the housing (2) are aligned parallel to form a gap (12).

10. Use of a centrifugal pump arrangement (1) as a fish-friendly pump to reduce shear forces between impeller (5) and housing (2).

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