Flow pump

Abstract

A centrifugal pump, in particular a radial pump, with a housing having at least one suction port (1), at least one discharge port (2) and an inner housing forming a flow channel (6), in which an impeller (3) open at least on one side with impeller blades (13) is rotatably arranged about a drive axis (A), wherein the suction port (1) has an end face (8) facing the impeller (3), is designed such that the edges (23) of the impeller blades (13) facing the suction port (1) each have a height offset (h) over their length, which corresponds to a circumferential projection (11) of the end face (8) of the suction port (1).

Description

[0001] The invention relates to a flow pump, particularly a centrifugal pump, in particular a radial pump or radial centrifugal pump, in whose housing the fluid to be pumped is sucked in via an intake port by means of a motor-driven impeller and pumped in the desired direction via a flow channel and a discharge port. Such a pump is known, for example, from EP 3 922 855 A1.

[0002] While pumps with a closed impeller geometry, where the impeller is covered in the axial direction on both sides of the impeller blades, are optimized for efficiency, impellers that are open at least on one side towards the intake side are used to pump fluids containing solids, as pumps constructed in this way are less prone to blockages and easier to clean. However, this also results in a lower efficiency, which is caused by the constant, slight backflow of pumped fluid from the flow channel past the impeller blades into the area of ​​the intake nozzle and the interior of the impeller.

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

[0004] Due to the design according to the invention, in which the edges of the impeller blades on the open side of the impeller, their side facing the intake port, each have a height offset over their length and the intake port has a circumferential projection on its end face facing these impeller edges that corresponds to the height offset, whereby the impeller edges and the end face of the intake port engage with each other, a fluid return or gap flow is deflected in such a way that it does not flow straight in towards the drive axis, but is directed back into the impeller in the main flow direction directly. The fluid inflow in the pump inlet is thereby not impeded or disrupted, or at least to a considerably lesser extent. The flow can therefore be linear from the pump inlet to the blade inlet.Despite the double edge created by the height offset of the impeller blades, an open impeller geometry is maintained, thus also providing the advantages of easier cleaning. Thread algae and other coarse contaminants can still be pumped, which is particularly necessary for the use of the pump according to the invention as a filter pump, for example, for ponds or aquariums.

[0005] Therefore, the impeller and intake manifold should preferably be designed and coordinated in such a way that the fluid flowing back into the impeller is directed away from the front of the intake manifold and back into the impeller. This has no or only marginal impact on the intake manifold's inflow cross-section. This results in less turbulence than with conventional pumps with an open impeller geometry.

[0006] A pump impeller design with double edges on the impeller blades, i.e., exactly one vertical offset per impeller blade, is generally sufficient to achieve the desired return flow deflection. However, the invention does not preclude designs with multiple vertical offsets on the impeller blade edges, thus achieving multi-stage flow deflection.

[0007] Preferably, the impeller blades are designed such that they have a greater height in the area closest to the outer circumference of the impeller, i.e., toward the outside, than in the area closest to the drive axis. The projection of the front side of the intake manifold is then formed on the inside of the intake manifold, facing the drive axis, so that the impeller blades encompass this projection with their area of ​​greater height on the outside, toward the flow channel. In this way, the backflow or gap flow is specifically directed away from the intake manifold.

[0008] According to a preferred embodiment, the height offset on the edge of the impeller blade is positioned such that the radial distance of the height offset from the drive axis of the pump is greater than or equal to the distance of the projection of the intake nozzle from the minimum inside diameter of the intake nozzle in the inlet cross-section. This means that the length of the blade edge in the region of its reduced height projected onto a radial section through the impeller at the inner leading edge of the impeller blade is less than or equal to the distance of the projection of the intake nozzle from its minimum diameter. As a result, a return flow takes place through the intake nozzle unaffected by the inner inlet flow. If the inner edge of the impeller blade even steps back compared to the minimum inside diameter of the intake nozzle, the inflow through the intake nozzle takes place completely unaffected by the return flow.Gap flow from the flow channel, since the latter passes directly into the free area of ​​the impeller.

[0009] An optimized flow pattern and the formation of a laminar flow from the intake port into the pump impeller are also achieved if the projection of the front end of the intake port toward the drive axis has an arcuate, particularly circular, shape in a section along the drive axis. The wall of the intake port can begin in a quarter-circular shape in section and then widen further toward the intake end of the intake port.

[0010] Particularly preferably, the height offset in the impeller blade edges is formed in a discontinuous or abrupt manner. In particular, a stepped height offset is also advantageous with regard to simple manufacturing. The height offset can preferably extend perpendicular to the edge regions of the impeller blade facing the intake manifold, in particular forming two substantially right angles with the two regions of the double edge. Simplifying design and manufacturing also contributes to the open edges of the impeller blades facing the intake manifold being arranged perpendicular to the drive axis and, in particular, being straight at least on one side, but preferably on both sides, of the height offset.

[0011] Further advantages and details emerge from the subclaims and a Figuren 1 and 3 illustrated embodiment; show: Fig. 1 shows a pump according to the invention in section, Fig. 2 shows a corresponding illustration of a conventional pump of the prior art for comparison and Fig. 3 shows the impeller of the pump from Fig. 1 in perspective view.

[0012] Fig. 1 shows a radial centrifugal pump in section. However, the invention is not limited to radial pumps. The pump has a housing which comprises an intake port 1 and a discharge port 2. The conveying direction of the fluid to be pumped is indicated there by arrows. Inside the housing there is an impeller 3 which is rotatably driven about a drive axis A by means of a drive shaft 4. In the embodiment shown here, the impeller 3 is designed as a semi-open impeller, i.e. open on one side, and is closed at the top towards the drive shaft 4, while it is open at the bottom towards the intake port 1. The impeller 3 used here has four impeller blades 13, of which Fig. 1 Due to the sectional view, only three are visible. When the impeller 3 rotates, it draws in the fluid to be pumped through the intake port 1 and conveys the fluid through the impeller blades 13 into a circumferential flow channel 6, which in this pump is designed as a spiral casing. The fluid is then discharged from the flow channel 6 through the discharge port 2.

[0013] In order to be able to clean the pump more easily, to enable the conveyance of solids transported in the fluid and to achieve a self-cleaning effect, the pump according to the invention is designed with an impeller geometry that is open on one side, whereby a constant low backflow, see arrow 7, occurs from the flow channel 6 between the impeller blades 13 and an end face 8 of the intake nozzle aligned with these into the area of ​​the impeller interior.

[0014] Fig. 2 shows a corresponding illustration of a conventional pump of the state-of-the-art. As indicated by the arrows, the gap flow or backflow 7 in this pump leads to turbulence in the inlet cross-section of the intake port 1 and thus to a reduction in the effectively usable cross-section 9.

[0015] In the pump according to the invention on Fig. 1 However, the impeller blades 13 are each provided with double edges 23, the shape of which Fig. 3 is clearly visible. The double edges 23 of the impeller blades, designed here as circular arc blades, are divided into an inner edge section 23i and an outer edge section 23a, between which a height offset h exists. Preferably, and as shown, the impeller blades have a greater height Ha in their outer section than in the inner section directed towards the drive axis A. The impeller blade edges 23, their height offset h, and their arrangement correspond to a projection 11 on the end face 8 of the intake manifold 1.

[0016] The return flow or gap flow 7 between the impeller blade edges 23 and the front side 8 of the intake nozzle 1 is formed by the double edges 23 of the impeller in Fig. 1 directed upwards along the impeller blades 13 and does not impair the inflow of the fluid to be pumped through the intake port 1. The effectively usable cross section 9 in the pump according to the invention is Fig. 1 hence the full inner cross-section of the intake port 1. A rounded transition in the cross-section of the intake port 1 to the projection 11 also contributes to a laminar flow. It is also advantageous if, as shown, the height offset h of the impeller blade edges 23 is set back from the minimum inner diameter 9 of the intake port 1, so that the gap flow 7 can adhere to the interior of the impeller blades 13 above the inner edge 23a and is evenly carried along by the incoming fluid, as shown by the arrows 12 in Fig. 1 show.

[0017] The design according to the invention enables the creation of a pump with significantly improved flow characteristics using a simple design.

Claims

1. Circulation pump, in particular radial pump, with a housing having at least one suction port (1), at least one discharge port (2) and an inner housing forming a flow channel (6), in which an impeller (3) open at least on one side with impeller blades (13) is arranged to be rotatable about a drive axis (A), wherein the suction port (1) has an end face (8) facing the impeller (3), characterized by the fact that the edges (23) of the impeller blades (13) facing the intake port (1) each have a height offset (h) along their length, which corresponds to a circumferential projection (11) of the end face (8) of the intake port (1).

2. Flow pump according to claim 1, characterized by the fact thatThe edges (23) of the impeller blades (13) with the height offset (h) and the end face (8) of the intake nozzle (1) with its circumferential projection (11) form a slot between them that is permeable to a fluid to be conveyed, the geometry of which is designed such that fluid flowing back from the flow channel (6) into the impeller (3) is directed along the impeller blades (13) away from the end face (8) of the intake nozzle (1) into the impeller (3).

3. Flow pump according to one of the preceding claims, characterized by the fact that the impeller blades (13) in their area (23a) closer to the outer circumference of the impeller (3) have a greater height (Ha) than in their area (23i) closer to the drive shaft (A) and the projection (11) of the front face (8) of the intake manifold (1) is located on its inner side facing the drive shaft (A).

4. Flow pump according to one of the preceding claims, characterized by the fact thatthe radial distance of the height offset (h) of the edge (23) of the impeller blade (13) from the drive axis is greater than or equal to the distance of the projection (11) of the intake port (1) from its minimum inner diameter (9).

5. Flow pump according to one of the preceding claims, characterized by the fact that the projection (11) of the front face (8) of the intake manifold (1) towards the drive axis (A) has an arc-shaped, in particular circular arc-shaped, course in a section along the drive axis (A).

6. Flow pump according to one of the preceding claims, characterized by the fact that the height difference (h) is abrupt.

7. Flow pump according to one of the preceding claims, characterized by the fact that the height difference (h) is designed in a step-like manner 8. Flow pump according to one of the preceding claims, characterized by the fact thatthe height offset (h) extends perpendicularly to the edge areas (23) of the impeller blade (13) facing the intake port (1).

9. Flow pump according to one of the preceding claims, characterized by the fact that the edges (23) of the impeller blades (13) facing the intake port (1) are arranged perpendicular to the drive axis (A).

10. Flow pump according to one of the preceding claims, characterized by the fact that the edges (23) of the impeller blades (13) facing the intake port (1) are straight at least on one side, preferably on both sides of the height offset (h).

Images