Flow pump

Abstract

The invention relates to a flow pump, in particular a radial pump, comprising a housing having at least one suction opening (1), at least one discharge opening (2) and an inner housing forming a flow channel (6), a single-sided open impeller (3) having impeller blades (13) being arranged rotatably about a drive axis (A), the suction opening (1) having an end face (8) facing the impeller (3), characterized in that the discharge opening (2) has an end face (8) facing the impeller (3). The edges (23) of the impeller blades (13) facing the suction opening (1) each have a height offset (h) over their length, which height offset (h) corresponds to the circumferential projection (11) of the end face (8) of the suction opening (1).

Description

Technical Field

[0001] The invention relates to a flow pump, in particular a centrifugal pump, in particular a radial pump or radial centrifugal pump, in which a housing sucks the fluid to be conveyed through an inlet pipe via an impeller driven by a motor and conveys it in the desired direction via a flow channel and a pressure pipe. Such a pump is known, for example, from EP 3 922 855 A1. Background Art

[0002] While pumps with closed impeller geometry, where the impeller is covered on both sides of the impeller blades in the axial direction, are optimized in terms of efficiency, impellers that are open on at least one side are used for conveying fluids containing solids, since such pumps are less prone to clogging and are easier to clean. However, this is at the expense of lower efficiency, since the conveying fluid continuously and in small quantities flows back from the flow channel past the impeller blades into the suction port and into the interior of the impeller.

[0003] The invention is based on the object of providing a pump having improved pump performance. This object is achieved by a flow pump having the features of claim 1 . Summary of the invention

[0004] By the design of the present invention, the edges of the impeller blades on the open side of the impeller facing the suction port each have a height offset over their length, and the suction port has a circumferential protrusion corresponding to the height offset on its end face facing these impeller edges, thereby redirecting the fluid backflow or gap flow so that it does not flow directly to the drive shaft center, but is redirected to the inside of the impeller along the mainstream direction. Therefore, the fluid flow at the pump inlet will not or at least will not be significantly obstructed or disturbed. Therefore, the flow from the pump inlet to the blade inlet can be linear. Although the height offset of the impeller blade edge forms a double edge on its edge, the open impeller geometry is still maintained, thereby also retaining the advantage of easy cleaning. In addition, for example, filamentous algae and other coarse impurities can still be transported, which is particularly important for using the pump of the present invention as a filter pump (for example, for ponds or aquariums).

[0005] Therefore, the impeller and the suction port are preferably designed and coordinated geometrically so that the fluid flowing back to the impeller is guided back to the impeller from the end face of the suction port. This ensures that the flow cross section of the suction port is not affected or only marginally affected. Compared to conventional pumps with open impeller geometry, the turbulence is less.

[0006] One possible design of a pump impeller with double edges of impeller blades, i.e. only one height offset on each impeller blade, is usually sufficient to achieve the desired flow redirection. However, the invention does not exclude designs with multiple height offsets on the impeller blade edges and thus multiple stages of flow redirection.

[0007] Preferably, the impeller blades are designed so that they have a greater height near the outer edge of the impeller, i.e., toward the outside, than near the inner edge, i.e., near the drive shaft. The protruding portion at the front end of the suction port is formed on the inner side toward the drive shaft, so that the impeller blades are closely attached to this protruding portion with their larger outer height area and guided toward the flow channel. This effectively guides the backflow or leakage flow out of the suction port.

[0008] Preferably, the impeller blades are designed to have a height near the outer edge of the impeller, i.e., toward the outside, greater than a height near the inner edge, i.e., a region near the drive shaft. Then, a protrusion is formed on the inner side facing the drive shaft in front of the suction port so that the impeller blades surround the protrusion with their outer edge portions with a greater height toward the flow channel. This effectively guides the backflow or leakage flow away from the suction port.

[0009] In order to achieve an optimal flow pattern and the formation of a laminar flow from the suction port to the pump impeller, it is also helpful if the protrusion on the front side of the suction port has an arc-shaped profile, in particular a circular arc-shaped profile, in a cross section along the drive axis. The wall of the suction port can start in the shape of a quarter circle in cross section and then expand further toward the inlet end of the suction port. This helps to achieve an optimal flow pattern and the formation of a laminar flow from the suction port to the pump impeller.

[0010] It is particularly preferred that the height offset of the impeller blade edge is formed abruptly or in a stepped manner. In particular, a stepped height offset is also advantageous in terms of simple manufacturing. The height offset preferably extends perpendicularly to the edge area of ​​the impeller blade facing the suction inlet, in particular forming two substantially right angles with the two areas of the double edge. For ease of construction and manufacturing, it is also beneficial if the open edge of the impeller blade facing the suction inlet is arranged perpendicular to the drive axis and is in particular a straight line on at least one side of the height offset, preferably a straight line on both sides. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the dependent claims and Figure 1 and Figure 3 Further advantages and details can be found in the illustrated embodiment, which show:

[0012] Figure 1 : Diameter diagram of a pump according to the invention,

[0013] Figure 2 : For comparison, a schematic diagram of a corresponding conventional pump of the prior art is shown, and

[0014] Figure 3 : Figure 1 A perspective view of the impeller of the pump. DETAILED DESCRIPTION

[0015] Figure 1 A cross-sectional view of a radial centrifugal pump is shown. However, the invention is not limited to radial pumps. The pump has a housing with a suction port 1 and a discharge port 2. The flow direction of the fluid to be pumped is indicated by an arrow. In the housing, there is an impeller 3 which can be rotated about a drive axis A by a drive shaft 4. In the illustrated embodiment, the impeller 3 is designed as a semi-open impeller, i.e. it is open on one side, closed on the upper side facing the drive shaft 4, and open on the lower side facing the suction port 1. The impeller 3 used here has four impeller blades 13, which are not shown in the cross-sectional view. Figure 1 Only three of them can be seen in the figure. When the impeller 3 rotates, it draws in the fluid to be pumped through the suction port 1 and conveys the fluid via the impeller blades 13 into the circumferential flow channel 6, which in the present pump is formed as a spiral housing. The fluid is then discharged from the pump through the discharge port 2.

[0016] In order to facilitate easier cleaning of the pump, allow solid particles to be transported in the fluid to be pumped, and achieve a self-cleaning effect, the pump of the present invention adopts an impeller geometry design with an opening on one side, which results in a continuous low backflow (indicated by arrow 7) from the flow channel 6 between the impeller blades 13 and the suction end face 8 aligned with them, into the inner area of ​​the impeller.

[0017] Figure 2 A corresponding schematic diagram of a conventional pump in the prior art is shown. As indicated by the arrows, the gap flow or backflow 7 in this pump causes turbulence in the inflow cross section of the suction port 1, thereby reducing the effective available cross section 9.

[0018] On the other hand, Figure 1 In the pump according to the invention shown, each impeller blade 13 has a double edge 23, the shape of which is Figure 3 The double edge 23 of the impeller blade, here designed as an arc blade, is divided into an inner edge 23i and an outer edge 23a, with a height offset h between them. Preferably, and as shown in the figure, the height Ha of the impeller blade in its outer part is greater than the height of the part facing the drive axis A. The impeller blade edges 23, their height offset h and their arrangement correspond to the protrusion 11 on the end face 8 of the suction port 1.

[0019] exist Figure 1 In the embodiment, the gap flow or backflow 7 between the impeller blade edge 23 and the end face 8 of the suction port 1 is guided upward along the impeller blade 13 by the double edge 23 of the impeller, and does not affect the inflow of the fluid transmitted through the suction port 1. Figure 1The effective usable cross section 9 in the pump according to the invention is the entire internal cross section of the suction port 1. The smooth transition of the cross section of the suction port 1 to the protrusion 11 also contributes to the laminar flow. It is also advantageous that the height offset h of the impeller blade edge 23 is rebounded from the minimum inner diameter 9 of the suction port 1 as shown in the figure, so that the gap flow or return flow 7 can adhere to the inner side above the inner edge 23a of the impeller blade 13 and be evenly carried by the inflowing fluid, such as Figure 1 As shown by arrow 12 in FIG.

[0020] According to the embodiment of the invention, a pump having significantly improved flow characteristics can be constructed in a structurally simple manner.

Claims

1. Flow pumps, especially radial pumps, including: A housing having at least one suction opening (1), at least one discharge opening (2) and an inner housing forming a flow channel (6), wherein a single-sided opening impeller (3) having impeller blades (13) is rotatably arranged around a drive axis (A), The suction port (1) has an end face (8) facing the impeller (3), characterized in that the edges (23) of the impeller blades (13) facing the suction port (1) have a height offset (h) over their length, which corresponds to the circumferential protrusion (11) of the end face (8) of the suction port (1).

2. The flow pump according to claim 1, characterized in that The edge (23) of the impeller blade (13) with a height offset (h) and the end surface (8) of the suction port (1) form a permeable groove for conveying fluid, and the geometric shape of the permeable groove is designed to allow the fluid flowing back from the flow channel (6) to the impeller (3) to enter the impeller (3) along the impeller blade (13) away from the end surface (8) of the suction port (1).

3. A flow pump according to any one of the preceding claims, characterized in that The height (Ha) of the impeller blades (13) in an area (23a) close to the outer periphery of the impeller (3) is greater than the height in an area (23i) close to the drive axis (A), and the protrusion (11) of the end surface (8) of the suction port (1) is located on the inner side facing the drive axis (A).

4. A flow pump according to any one of the preceding claims, characterized in that The radial distance from the height offset (h) of the edge (23) of the impeller blade (13) to the driving axis is greater than or equal to the distance from the protrusion (11) of the suction port (1) to its minimum inner diameter (9).

5. A flow pump according to any preceding claim, characterised in that In a cross section along the drive axis (A), a protrusion (11) of the end surface (8) of the suction port (1) toward the drive axis (A) presents an arc-shaped profile, in particular a circular arc-shaped profile.

6. A flow pump according to any preceding claim, characterised in that The height deviation (h) is sudden.

7. A flow pump according to any preceding claim, characterised in that The height offset (h) is formed in a step-like manner.

8. A flow pump according to any preceding claim, characterised in that The height offset (h) extends vertically to the edge (23) of the impeller blade (13) facing the suction inlet (1).

9. A flow pump according to any preceding claim, characterised in that The edge (23) of the impeller blade (13) facing the suction port (1) is arranged perpendicular to the drive axis (A).

10. A flow pump according to any preceding claim, characterised in that The edge (23) of the impeller blade (13) facing the suction opening (1) is straight on at least one side of the height offset (h), preferably on both sides.

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