EP2628958A2 - Diffuser for an impeller pump and impeller pump - Google Patents

Abstract

The stator (25) has a base (27) which is annularly rotated about a central longitudinal axis for arrangement in a pump chamber of impeller pump. The outwardly projecting blades (29) are arranged at pitch relative to the longitudinal axis on a radially outer side of the base such that blades overlap each other along circumferential direction of the base. A projection or thickener portion (32) is formed in blade at outer edge (30). An independent claim is included for impeller pump.

Description

The invention relates to a stator for an impeller pump, as used in particular as a heated impeller pump in household appliances such as dishwashers or washing machines. Furthermore, the invention relates to an impeller pump with such a stator.

From the DE 102007017271 A1 is known a corresponding impeller pump. It has a stator radially outside of the inlet nozzle in the pump chamber, which serves for improved guidance of the liquid to be heated in the impeller pump or in the pump chamber.

Task and solution

The invention has for its object to provide an aforementioned stator and a corresponding impeller pump with which problems of the prior art can be avoided and in particular a further improved function of the impeller pump or water supply is possible.

This object is achieved by a stator with the features of claim 1 and an impeller pump provided with the features of claim 13. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. Some of the features are only mentioned for the stator or only for the pump. However, they should be able to apply independently to both the stator and the pump. The wording of the claims is incorporated herein by express reference.

It is envisaged that the stator has a base body which is annularly circulating with a central longitudinal axis, to which the base body can be rotationally symmetrical, and which is also designed to be arranged in a pump chamber of the impeller pump. For this arrangement will be explained in more detail later. At least one blade is arranged on a radial outer side of the main body, advantageously a plurality of which projects outwards and runs along this at least part of the circumferential direction of the main body. In this case, the blade has a pitch compared to the central longitudinal axis, advantageously in the manner of a helix.

According to the invention it is provided that at least on one side or surface of the blade at the outer edge of a projection or a thickening is provided, which can advantageously form a kind of lip. This means that the blade is not only flat with regard to its cross-sectional area or straight line, under some circumstances also slightly tapered towards the outer edge, as is known from the prior art. Advantageously, it is just on at least one side still provided with the projection or the thickening, which results in a significantly improved efficiency of the water supply found within the scope of the invention. By this projection or the thickening can be generated or formed together with the shape of the other blade a kind of channel. In this air bubbles in the liquid, which is located in the pump chamber, ascend or move generally toward the outlet nozzle from the pump chamber. Furthermore, here individual air bubbles can collect to larger air packets, which in turn can then be transported faster from the pump due to the significant difference in density to the water or the liquid conveyed. Thus, the problem is that by starting the pump or by sucking air during operation, air can be inside the pump, which is disturbing, and can be carried out as quickly as possible. Especially with heated impeller pumps otherwise forms with existing air to heating elements that are in the pump chamber or adjoining it, a heat pad by not sufficiently removed due to air bubbles amount of heat. Such heat cushions can lead from failure to destruction of the pump. Therefore, the venting of such a heated impeller pump is of great importance.

By the aforementioned projection or the thickening on the outer edge of the blade, a diffuser-like behavior or effect can be generated in addition. This results in a slight pressure increase in the pump chamber, which also leads to an improvement in the promotion effect or the efficiency of the pump by the constant power.

In an embodiment of the invention, the stator may have at least three blades. It is advantageous four or five blades or even more, running along the outside of the body. Particularly advantageously, the blades almost overlap in the circumferential direction, so that virtually a continuous blade effect can be generated around the main body of the stator.

In an advantageous embodiment of the invention, the base body has a certain height in the direction of the central longitudinal axis, so that its cross section may be quasi oblong or rectangular with a relatively small thickness compared to the height. At least one blade may extend in its longitudinal course over substantially the entire height of the body, advantageously all blades. In a particularly advantageous manner, the blades are generally identical in each case.

The blades can advantageously also be designed so that their pitch is substantially constant. Alternatively, they can be in

Direction of the central longitudinal axis, ie in the direction of the axial flow component of the pumped in the pump chamber water, decreasing or increasing slope. As a result, an influencing of these axial flow components is possible and an acceleration of the water can be varied in the axial direction. In a further embodiment of the invention can be provided that the blades of the main body do not protrude exclusively in the radial direction, but slightly inclined. They can have an angle α between 60 ° and 80 ° to the central longitudinal axis. The projection or the thickening is particularly advantageously arranged on that side of the blade, which has the larger angle to the central longitudinal axis or which is inclined or angled towards the base body more.

In a further advantageous embodiment of the invention can be provided that the thickness or height of the projection or the thickening decreases, in particular seen approximately in the axial direction, advantageously monotonously or continuously. In this case, neither the blade nor the projection or the thickening should project beyond the height of the base body in the direction of the central longitudinal axis. A decrease in the thickness or height of the projection or the thickening is advantageously along the axial direction of the pump against the axial flow component of the water or in this axial direction of the water flow, the thickness or height of the projection or the thickening increases.

At the thickest or highest point, the projection or the thickening can be approximately twice the thickness of the blade, particularly advantageously about as thick as the blade and thus form a distinct lip on the edge. A change in the thickness or height of the projection or the thickening may be such that at the thinnest point completely disappears or almost disappears and only is still quite easily provided on the blade. Advantageously, the projection or the thickening is provided just at the edge of the blade or a blade side. It is advantageous if the projection or the thickening is rounded in cross-section, both radially outwardly and radially inwardly and also at the highest point. As a result, turbulences in the pumped liquid can be reduced.

In a further advantageous embodiment of the invention, the base body is formed substantially as a ring in the manner of a short pipe section. Inner side and / or outer side can be straight and run parallel to the central longitudinal axis. In this case, the diameter of the base body can be approximately four times to ten times the height of the base body. The height of the body in turn is about four times to ten times its thickness. Furthermore, the thickness of the blades can be approximately in the region of the thickness of the base body, advantageously somewhat thinner to half or even only up to one third of its thickness.

The main body is advantageously made of a rather solid material and is particularly rigid. The preferred integrally molded or molded blade advantageously consist of the same material, alternatively, a two-component syringes with at least partially made of elastic material blades is conceivable. The projection or the thickening is advantageously also integrally formed on the blade, particularly advantageously made of the same material.

As has been explained, the impeller pump according to the invention has a pump chamber in which the impeller rotates. An inlet port leads into the pump chamber and toward the impeller, with an outlet port extending from the pump chamber, particularly at the end of the pump chamber axially remote from the impeller. According to the invention, a prescribed stator with a projection or a Thickening placed over an extension of the inlet nozzle in the pump chamber, on the outside thereof. In this case, the stator or its blades should not extend to the radially outer Pumpenkammerwandung, but have a distance therefrom, which can range from half the width of the blades to twice the width.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combination in one embodiment of the invention and in other areas be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections as well as intermediate headings does not restrict the general validity of the statements made thereunder.

Short name of the drawings

Fig. 1

eine Schnittdarstellung durch eine erfindungsgemäße Impellerpumpe mit einem erfindungsgemäßen Leitrad,

Fig. 2

eine Schrägdarstellung eines erfindungsgemäßen Leitrades mit vier Schaufeln samt Lippen von schräg unten,

Fig. 3

eine Schnittdarstellung durch einen Bereich des Leitrades entsprechend Fig. 2 zur Verdeutlichung des Profils der Lippe,

Fig. 4 bis 6

drei verschiedene Ausbildungen für eine solche Lippe entsprechend Fig. 3,

Fig. 7

eine Drosselkennlinie einer Impellerpumpe einmal mit üblichem Leitrad und einmal mit erfindungsgemäßem Leitrad,

Fig. 8

der hydraulische Wirkungsgrad über der Durchflussrate,

Fig. 9

der Verlauf der Leistung über der Zeit zur Entlüftung der Pumpenkammer.

Embodiments of the invention are shown schematically in the drawings and are explained in more detail below. In the drawings show:

Fig. 1

a sectional view through an impeller pump according to the invention with a stator according to the invention,

Fig. 2

an oblique view of a stator according to the invention with four blades including lips from below obliquely,

Fig. 3

a sectional view through a portion of the stator accordingly Fig. 2 to clarify the profile of the lip,

4 to 6

three different training for such a lip accordingly Fig. 3 .

Fig. 7

a throttle characteristic of an impeller pump once with conventional stator and once with a stator according to the invention,

Fig. 8

the hydraulic efficiency over the flow rate,

Fig. 9

the course of the power over time to vent the pump chamber.

Detailed description of the embodiments

In Fig. 1 a pump 11 according to the invention is shown in section, as they are of the construction essentially of the aforementioned DE 102007017271 A1 , to which reference is explicitly made in this respect, corresponds to a radial pump or impeller pump. It can be used advantageously in a dishwasher or washing machine. The pump 11 has a pump housing 12 with inlet 13, outlet 14 and pump chamber 16. Close to a pump chamber bottom, a conventional impeller 18 is arranged as the impeller. It is driven by an unspecified pump motor 20. By rotation of the impeller 18 fluid is sucked to the inlet 13 in the axial direction along the dashed longitudinal center axis L of the pump 11 and ejected from the impeller 18 in the radial direction. Then, the fluid in the pumping chamber 16 is circulated, as shown in FIG Fig. 1 left into the plane and right out, and finally exits after several rounds at the outlet 14 from the pump 11.

To the outside, the pump chamber 16 is delimited by a heating device 22, which therefore also simultaneously forms an aforementioned radially outer pump chamber wall. As can be seen, the heater 22 seals the pump chamber 16 as a radially outer pump chamber wall via two circumferential sealing rings 23a and 23b, respectively, and is sealingly connected to the pump housing 12.

Furthermore, it can be seen that a stator 25 is arranged according to the invention on a pipe socket 24 around the inlet 13 or this is placed on the pipe socket 24 and fixed there, for example, by clamping snug fit. The stator 25 has an annular base body 27, on the outside projecting several blades 29 are provided. The structural design is hereinafter in connection with the Fig. 2 to 6 explained in more detail.

How out Fig. 1 can be seen, the blades 29 are arranged at a slight angle or angle to the base body 27, and they are at an angle α of about 75 ° to the longitudinal central axis L or are in the flow direction of the liquid in the pump chamber 16 with the axial flow component S of inclined like a ring or helical rotating funded water. The angle α is not directly in Fig. 1 marked but recognizable. This will also be explained in more detail below.

From the oblique view in Fig. 2 It can be seen that 27 four blades 29 are arranged on the stator 25 with the annular base body. It can be seen that the blades 29 each make almost a quarter turn around the base body 27 and thus almost overlap in the circumferential direction or nearly reach each other in the circumferential direction. The slope of the blades 29 in relation to the longitudinal central axis L from Fig. 1 varies here. It can be seen on the front blade 29 that the slope is flatter lower right first, then increases more and then remains the same in a slightly longer range. The axial flow component S is shown for comparison. This means that in the pump 11, the pitch of the blades 29 at the beginning, so close to the pump chamber bottom 17, is slightly larger and then slightly decreases.

Furthermore, it can already be seen here that on an outer edge 30, a projection on top of the side of the blades 29 is placed or formed as a projection 32. This can be even better from the enlarged sectional view in the 3 and 4 seen. Usually would the blade 29 to the outer edge 30 out approximately constant thickness. By the above molded projection 32, which forms a kind of lip, the profile of the blade 29 is changed. Above all, it can also be seen how, in comparison to the axial flow component S, a type of channel 34 is formed between the projection 32 and, to the right inwards, the corresponding outer side of the main body 27. This channel 34 simply improves the outflow of air bubbles in the circumferential direction Water. On the channel bottom, which is formed by the region of the blade 29 between the base body 27 and projection 32, the air bubbles can collect very well, accumulate and be transported away. Furthermore, they are so far away in any case from the inside of the heater 22 and there can no longer cause the above-mentioned problems of over-temperature.

Furthermore, it is off Fig. 2 it is easy to see that the thickness or height of the projection 32 decreases in the course of the blades 29. This takes place in the direction of view along the axial flow component S in the clockwise direction or in the case of the front blades 29 from the bottom right to the top left. The decrease in thickness or height can be such that it goes to zero. Given the representations in Fig. 3 For example, the normal thickness of the blades 29 may be about 2 mm, and the maximum height of the projection 32 may be 1 mm to 2 mm.

In Fig. 4 is shown as an alternative embodiment of a blade 29a with a projection 32a at the outer edge 30a, a cross-section which is substantially triangular and thereby edged or pointed. Such a pointed configuration of the cross section of the projection 32 with a correct tip can cause a promotion of air bubbles better in the channel 34a to the main body 27a out is possible. The height of the projection 32a is slightly below the thickness of the blade 29a.

In the modification according to Fig. 5 a projection 32b is also arranged again on the outer edge 30b of the blade 29b. Here, too, the projection 32b is substantially triangular and pointed in cross-section, the tip 33b being inclined far inward over the channel 34b towards the base body 27b. As a result, the channel 34b becomes more closed, so to speak. Another embodiment is made Fig. 6 can be seen in the case of a projection 32c on the outer edge 30c of a blade 29c, the tip 33c is inclined outwardly. In this case, it is even inclined in the radial direction beyond the outer edge 30c or projects beyond it. Here, unlike the opposite or to the design of the channel 34b, respectively Fig. 5 the channel 34c is even more open.

For the variations of the projections 32a to 32c, it should be noted that they may also be less pointed or the tips 33a to 33c may be more rounded.

From the diagram of Fig. 7 It can be seen how in the dashed curve of the pressure difference over the flow rate behaves in a stator according to the prior art, for example, according to the aforementioned DE 102007017271 A1 , Compared to a stator according to the invention with a projection or lip on the outer edge 30 of the blade 29 with the solid curve. The upper curve represents just for an exemplary pump, the pressure difference for the stator according to the invention. It can be seen that this curve, although only slightly, but significantly above the other curve.

Especially with increase in the flow rate of the pressure difference can be increased slightly, in particular 5 mbar reach to even slightly more than 10 mbar, thus causing an improvement of several percent.

In Fig. 8 is in each case the hydraulic efficiency of the two guide wheels accordingly Fig. 7 applied. Here it can be seen that the measurements on the pump showed no increased power requirement, that from a volume flow of about 40 l / min, the hydraulic efficiency is slightly improved, namely between 0.4% and just under 1%. Thus, an advantage can be achieved, especially for larger flow rates.

In Fig. 9 in each case the course of the required power over time for a venting process in the pump 11 is shown, so if there are air bubbles in the water conveyed there. Here it can be seen that it can be seen from the course of the performance that in a stator according to the invention with a projection on the blades due to the faster increase in power venting is completed earlier or has been made.

Claims (15)

Guide wheel for an impeller pump, in particular a heated impeller pump for household appliances such as dishwashers, with a base body which is annular with a central longitudinal axis and which is designed for arrangement in a pump chamber of the impeller pump, wherein at least one blade is arranged on a radial outer side of the main body, which protrudes outwards and at least a portion of the circumferential direction along this runs and thereby has a slope compared to the central longitudinal axis, characterized in that at least on one side of the blade at the outer edge of a projection or a thickening is provided. Guide wheel according to claim 1, characterized in that it comprises at least three blades, which almost overlap in particular in the circumferential direction. Guide wheel according to claim 1 or 2, characterized in that the base body has a certain height in the direction of the central longitudinal axis and at least one blade extends in its longitudinal course over substantially the entire height of the base body. Guide wheel according to one of the preceding claims, characterized in that at least one blade has a substantially constant pitch. Guide wheel according to one of the preceding claims, characterized in that the blades of the main body do not protrude in an exclusively radial direction, but slightly inclined. Guide wheel according to claim 5, characterized in that the projection or the thickening is arranged on that side of the blade which has the larger angle to the central longitudinal axis. Guide wheel according to claim 5 or 6, characterized in that the blades protrude from the base body at an angle between 60 ° and 80 ° to the central longitudinal axis. Guide wheel according to one of the preceding claims, characterized in that the thickness or height of the projection or the thickening in the longitudinal course along the blade monotonically or continuously decreases. Guide wheel according to claim 8, characterized in that neither the blade nor the projection or the thickening projects beyond the height of the base body in the direction of the central longitudinal axis. Guide wheel according to one of the preceding claims, characterized in that the thickness or height of the projection or the thickening of a maximum of twice the thickness of the blade decreases to zero. Guide wheel according to one of the preceding claims, characterized in that the base body is formed substantially as a ring in the manner of a short pipe section, wherein in particular the diameter of the base body is approximately four times to ten times the height of the base body. Guide wheel according to claim 11, characterized in that the ring in the manner of a short pipe section with a straight inside and / or outside is formed which extend parallel to the central longitudinal axis. Impeller pump with a stator according to one of the preceding claims, wherein the impeller pump has a pump chamber with an impeller rotating therein, wherein an inlet nozzle leads into the pump chamber to the impeller and from the pump chamber an outlet nozzle, characterized in that the stator via an extension of the inlet nozzle is placed in the pump chamber on the outside thereof. Impeller pump according to claim 13, characterized in that the thickness or height of the projection or the thickening in the direction away from the impeller to the outlet nozzle increases along the extension of the projection or the thickening of the blade. Impeller pump according to claim 13 or 14, characterized in that the stator has four or five blades, which almost adjoin one another in the circumferential direction, wherein preferably the blades have the same and continuous width.

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