Pump   

Abstract: A radial pump for fluids has a central water inlet that leads to a rotating impeller that is enclosed by an annular pump chamber extending radially outside the impeller and from which leads a water outlet. An intermediate wall is arranged in the pump chamber which is of an encompassing design and divides the pump chamber into an annular inner region, lying radially on the inside, and an annular outer region, lying radially on the outside. These regions, at one end of the pump chamber that is remote from the impeller, merge into each other through openings in the intermediate wall, wherein the water outlet projects from the outer region.

This application claims the benefit of German patent application DE 10 2011 079 510.3, filed on Jul. 20, 2011, the contents of which are incorporated by reference for all that it teaches.

The invention relates to a pump as is used especially in a water-conducting domestic appliance, such as a washing machine or a dishwasher.

A radial impeller pump is known from EP 2 150 165 A, corresponding to U.S. Patent Application Publication No. 2010/0126534, describing a pump with a central water inlet and an impeller in an annular pump chamber. In that disclosure, the water, after a number of circulations in the pump chamber, is led out in the tangential direction towards a water outlet which is provided at the water inlet in the region of the end of the pump.

SUMMARY

The disclosure herein is based on the object of creating a pump of the type referred to in the introduction, with which problems of the prior art can be avoided and, particularly in the case of a pump of the type referred to in the introduction, the effect can be achieved of the pump requiring as little installation space as possible in the region of the water inlet, or the water outlet being at a greater distance from the water inlet for a more versatile or more favourable arrangement in a domestic appliance.

This object is achieved by a pump having the features described and claimed herein. Advantageous and preferred embodiments are the subject matter of the further claims and are explained in more detail below. The wording of the claims is rendered by express reference to the contents of the description.

According to various concepts and technologies described herein, a radial pump for fluids may have a central water inlet leading to a rotating impeller that is enclosed by an annular pump chamber extending radially outside the impeller and from which leads a water outlet. An intermediate wall divides the pump chamber into an annular inner region, lying radially on the inside, and an annular outer region, lying radially on the outside. These regions, at one end of the pump chamber that is remote from the impeller, merge into each other through openings in the intermediate wall, wherein the water outlet projects from the outer region.

These and additional features, other than from the claims, are also gathered from the description and the drawings, wherein the individual features can be put into effect separately by themselves in each case or in multiples in the form of sub-combinations in an embodiment of the invention and in other fields, and can represent advantageous and separately protectable embodiments, for which protection is claimed here. The subdivision of the application into individual sections and also into sub-headings does not limit the statements made under these in their generality.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the disclosure are shown schematically in the drawings and are explained in more detail in the following text. In the drawings:

FIG. 1 shows a schematic longitudinal section through a pump with division of the pump chamber into an annular inner region, an annular outer region and an intermediate wall in between according to various embodiments;

FIG. 2 shows an oblique view from the outside of the pump corresponding to FIG. 1 with a view of the arrangement of the water outlet on the outer side remote from the water inlet according to various embodiments;

FIG. 3 shows a sectional view through a heating element on the outside wall of the outer region according to various embodiments; and

FIG. 4 shows a section through an alternative heating device which can form the intermediate wall between the inner region and the outer region according to various embodiments.

DETAILED DESCRIPTION

Prior to a detailed discussion of the various embodiments with reference to the figures, a general discussion of the disclosed pump and its operation will be provided. Concepts and technologies described below provide a radial impeller pump, or so-called centrifugal pump, having a central water inlet that leads to a rotating impeller as a feeder or compressor. The impeller is enclosed by an annular pump chamber, wherein this extends radially outside the impeller, or the impeller extends exactly centrally therein. A water outlet leads from the pump chamber in order to transfer the water which is delivered by the impeller.

According to one embodiment, provision or arrangement is made in the pump chamber for an intermediate wall, which in the circumferential direction may be of a completely encompassing design. This intermediate wall divides the pump chamber into an annular inner region, lying radially on the inside, and an annular outer region, lying radially on the outside. The inner region and the outer region merge into each other at one end of the pump chamber which is remote from the impeller, wherein to this end openings are provided in the intermediate wall and the intermediate wall is advantageously shortened overall. Furthermore, the water outlet projects from the outer region.

As a result, the effect is achieved of the delivered fluid remaining longer in the pump en route from the impeller to the water outlet. Longer in this case is to be understood in the sense of longer in time and also longer with regard to the delivery distance. This is particularly advantageous in the case of such embodiments in which the delivered fluid is heated, which is explained in more detail in the following text. In such an advantageous embodiment, a heating device is provided in or on the pump for heating the fluid while being delivered. In particular, the heating can then be carried out in an improved or more efficient manner. Furthermore, as a result of the intermediate wall with the transition from the inner region into the outer region and a deflection associated therewith, the possibility is provided of providing the water outlet at an essentially optional point in the axial direction of the pump, or of the pump chamber.

In another embodiment, it is possible that the intermediate wall is fastened to an end section of the pump chamber in the axial direction of the pump. This means that the intermediate wall extends essentially equidistantly to the inner region and to the outer region. In this case, the intermediate wall is advantageously fastened to, or arranged on, the pump in an encompassing and continuous manner, especially fastened to an end section, in fact especially advantageously close to the impeller. The openings in the intermediate wall for the transition of the inner region into the outer region are preferably provided in this case at the other end of the pump chamber from the fastening of the intermediate wall.

These openings may be advantageously formed as a shortening of the intermediate wall in the longitudinal direction of the pump towards the pump casing so that an encompassing, annular and continuous transition region from the inner region into the outer region is created. The intermediate wall can therefore have a distance from the pump chamber wall, or pump chamber, that is to say from the outer side. This distance can lie in the order of magnitude of the width of the entire pump chamber in the radial direction and should be slightly greater than the width of the pump chamber in the radial direction so that the flowing, delivered fluid can flow easily from the inner region into the outer region.

The impeller may be advantageously arranged close to a pump chamber bottom, the impeller extending especially advantageously directly above it. As previously mentioned, the intermediate wall may also be arranged on this pump chamber bottom, or may be connected to said bottom in this end region of the pump chamber. It may be preferred if this is the end of the pump on which the motor for driving the impeller is provided.

In another embodiment, the water outlet is located at the level of, or radially outside, the impeller. This is advantageously the end of the outer region in the direction towards the pump chamber bottom. As a result, the effect can be achieved of the fluid delivered by the pump covering a maximum distance as seen in the longitudinal direction of the pump, specifically at first from the impeller at one end of the pump chamber to the opposite end in the inner region. There, the fluid transfers into the outer region and is then in turn transported along the main part of the outer region up to the water outlet before it leaves the pump. This may be especially advantageous for an aforesaid possible heating of the fluid while being delivered, which is dealt with in more detail in the following.

It may be advantageously provided that the longitudinal extent of the inner region in the direction parallel to the rotational axis of the impeller, that is to say in the longitudinal direction of the pump, is approximately as large as that of the outer region of the pump chamber. As a result, a construction of the pump chamber, or of the pump, can be created in which a pump chamber which is provided without being split as such is divided by the intermediate wall into the inner region and the outer region which are then also approximately of equal length.

The widths of the inner region and of the outer region in the radial direction can be unequal. The outer region is advantageously wider, especially between 25% and 100% wider. As a result of such a wider outer region, the fluid flow in this case can be slowed down again somewhat at slightly lower pressure. However, if an acceleration of the fluid in the outer region at a pressure at the water outlet which is as high as possible should rather be desired, than the outer region, differing therefrom, can also be of a narrower design than the inner region.

As has been mentioned previously, the pump can advantageously be provided with heating. It is possible to heat the said intermediate wall, or the intermediate wall can have a heating device or can form a heating device. Preferred in this case is a flat heater which also achieves the best possible transfer of heat to the fluid delivered in the pump chamber. The advantage of a heated intermediate wall especially lies in the fact that this is exposed to circumflow by the fluid on both sides, especially on the outer side of the inner region. Therefore, a foreseeably good transfer of heat can be created. It could be a problem in this case that the heating device is actually also exposed to circumflow by water and therefore safety conditions can be critical. This could possibly be avoided by a heating device, provided on the intermediate wall or forming the intermediate wall, having a sandwich type of construction with two heating element carriers lying one on top of the other, advantageously consisting of correspondingly temperature-resistant plastic or metal, wherein these are laid one on top of the other with the heating elements towards each and with a corresponding electrical insulation in between.

Alternatively, two such carriers can also be provided with just a single heating element, that is to say on one of the two sides of the carriers. In one more alternative, a heating element can be provided on one of the carriers in each case and their pattern can be coordinated so that the heating elements do not lie opposite each other, or two heating elements do not lie one on top of the other.

Such a heating device in a sandwich type of construction, apart from an electrical supply lead or an electrical connection, can be sealed off in a watertight manner, for example by application of adhesive or by welding or soldering. A penetration through such a seal in the region of an electrical connecting lead can then be provided in a region inside the pump casing and, via a seal, separated from the pump chamber so that no sealing problems occur.

It is also possible that an outside wall around the outer region of the pump chamber is heated, or has or forms a heating device. In this case, provision can then be made for example for an outside wall or heating device according to DE 10 2010 003 464 A1, which is advantageously a metal tube with heating elements as a thick film heater applied on the outside. A heater is especially advantageously provided only on the radially outer outside wall of the outer region and not on the intermediate wall.

A heating device can form, cover, or occupy at least 50% of the intermediate wall or of the radially outer outside wall of the pump. This is advantageously even more, for example about 60% to 70%. As a result of the heater being distributed as extensively as possible, an advantageous transfer of heat from the heater to the delivered fluid can take place.

In the aforesaid case of a heated side or wall, especially the outside wall, the heating device can advantageously be a metal tube and itself can form the wall, or especially the outside wall, of the pump chamber. In this case, it is also designed for contact with the fluid which is delivered by the pump, either through suitable material selection, for example a high-grade steel which is suitable for use in the domestic appliance, or with a coating on the inner side towards the fluid, for example an enamel coating.

In the aforesaid transition region from the inner region to the outer region of the pump chamber, a rounding can be provided, as seen in side view. In this way, the delivered and circulating fluid can pass from the inner region into the outer region without a great deal of resistance.

In a further embodiment, it is possible in this case that guide vanes, which provide a swirl-like movement of the delivered fluid in a direction along the outside wall, are specially arranged in this transition region. These guide vanes therefore assist in the fluid being transferred from the inner region into the outer region and, in the process, also assist in the fluid being circulated on the one hand and being moved in the manner of a helical path towards the water outlet along the longitudinal direction of the pump on the other hand. Provision can advantageously be made in the circumferential direction for a plurality of guide vanes that have equal spacing and/or are of the same design.

In a further embodiment, it is possible that the radial width of the inner region and/or of the outer region along the longitudinal direction of the pump varies. Also, in connection with the aforesaid possible different radial widths of the inner region and the outer region, both the flow behaviour of the fluid between the impeller and the water outlet, and also fluid velocity and pressure at the water outlet, can be influenced as a result.

Referring now to the drawings, FIG. 1 shows a pump 11 according to one embodiment with a pump casing 13 and a pump motor 15, attached thereupon, which shall not be dealt with in more detail in the following text, however. A similar pump casing is known from EP 2 150 165 A, which is referred to above, with regard to the design from two plastic sections.

In the pump casing 13, provision is made in a top section 17 for a central and axial water inlet 19 that guides the water directly to an impeller 21. This impeller 21 is arranged just above a pump bottom 22 of a pump chamber 24 and is driven by the pump motor 15. The pump chamber 24 extends radially outside the impeller 21 in addition to the space that the impeller 21 itself occupies. It is to be seen how the pump chamber 24 is delimited radially towards the inside by an inside wall 25 of the top section 17.

At the end of the pump casing 13 which is remote from the pump motor 15, the top section 17 outwardly merges into a rounding, in fact approximately at the level of the water inlet 19, which, however, does not have to be so. Here, a heating device 26, which is designed as an essentially encompassing metal ring, is connected with sealing effect as the outside wall. Such a heating device 26 is basically known from the aforesaid DE 10 2010 003 464 A1, and is explained in more detail below in FIG. 3 with reference to a sectional representation.

Towards the pump motor 15, the heating device 26 merges into an outside wall 30 of a bottom section 18 which also forms, or has, the pump bottom 22. From FIG. 2, it is to be seen how a water outlet 32 projects tangentially from the outside wall 30 of the bottom section 18 in the manner of a pipe connector. This also lies close to the pump bottom 22 or close to the pump motor 15.

An intermediate wall 34 extends inside the pump chamber 24 between a radially inner inside wall 25 of the top section 17 and the outside wall 30 or the heating device 26, which also forms a large part of the outside wall. This intermediate wall 34 is also of an annularly encompassing design and, as is easy to see, projects from the pump bottom 22 on the bottom section 18. In this case, the intermediate wall extends parallel to the inside wall 25 and outside wall 30 or heating device 26. However, the intermediate wall 34, whereas it projects from the bottom section 18 in an encompassing manner and in one piece, on its left-hand free end 35 has a distance from the top section 17 in the curved region. This distance lies approximately in the order of magnitude of the distance of the intermediate wall 34 from the radially inside wall 25. Therefore, it is also easy to see that the flow cross section for the fluid which is delivered by the pump 11—the flow direction of which is indicated by the arrows—is increased only after the transition from an inner region 37 between inside wall 25 and intermediate wall 34 into an outer region between intermediate wall 34 and outside wall 30 or heating device 26, in fact may be approximately doubled. This, however, as has been already described previously, can also be otherwise, for example the cross sections of the inner region 37 and the outer region 39 can be approximately of equal size or the cross section of the outer region 39 can even be smaller. It is to be observed in the case of the flow arrows that they do not show the rotational movement of the water in the manner of a swirling motion for reasons of clarity. It should be clear in all cases, however, that the delivered water also makes several rotations or circulations in the inner region 37 and outer region 39 before reaching the water outlet 32.

Furthermore, in the transition region between inner region 37 and outer region 39, that is to say at the curvature of the top section 17, lying opposite the free ends 35 of the intermediate wall 34, provision is made for the guide vanes referred to in the introduction, for example being formed on the top section 17 or arranged on a separately attached insert. These guide vanes 40 effect a swirl-like motion of the delivered fluid along the outside wall in the form of the heating device 26, or in the outer region 39. In particular, the guide vanes 40 effect a direction reversal of the delivered fluid in the transition from the inner region 37 into the outer region 39.

From the sectional view in FIG. 3, the heating device 26 is shown in a schematically more discernible manner. It comprises a metal plate 27, which overall forms a closed ring, particularly a cylindrical shroud ring, and advantageously consists of high-grade steel. Attached on the metal plate 27 on the outside is an insulating layer 28, as is known per se to the person skilled in the art. A thick-film heating resistor 29 in flat form, as is also basically known to the person skilled in the art, is applied on top of the insulating layer 28. The surface of the thick-film heating resistor 29 can have various characteristics or shapes, that is to say does not have to be full-faced but can be formed, for example, by an elongated, spiral or meander-like strip. Temperature sensors or other electrical components, which are not shown either, and especially advantageously an electrical contact, can also be arranged on the outer side of the heating device 26.

The advantage of the arrangement of a heating device 26 as an outside wall on the outer region lies in the fact that in this case the radially circulating delivered fluid in all cases sweeps along with good contact and for a plurality of rotations. Therefore, a good yield of heat from the heating device 26 to the fluid is possible for heating of the delivered fluid that is altogether as efficient as possible.

Alternatively or additionally, the previously described intermediate wall 34 can also be heated. This in principle has the advantage that in this case the delivered fluid is heated both in its path through the inner region 37 and in its path through the outer region 39 and, as is quite obvious from FIG. 1, provision is made for a heating surface which is almost twice as large as in the case of the heating device 26 on the outside wall of the pump casing 13 alone.

An example of such a heated intermediate wall 134 is shown in FIG. 4. A metal plate 141 bent in the shape of a U is covered on its inner sides with an insulating layer 142. A thick-film heating resistor 143 is again arranged on top of the insulating layer 142 on both sides, in a similar way to that shown in FIG. 3. In this case, the thick-film heating resistors 143 of the top and the bottom halves are electrically isolated from each other and therefore have separate connections in each case, at least on the heating device 134 itself The production of such a heating device 134 is easily conceivable by imagining it being opened out with a flat continuous metal plate 141. It then exists in the form of an elongated rectangular strip and is provided with the insulating layers 142 and the thick-film heating resistors 134. In the region of the free end 135 formed later, which points to the left in FIG. 4, the layers on the metal plate 141 are advantageously omitted so that an easy bending round later is possible here. Either the bending round goes only to such extent that the thick-film heating resistors 143 do not make contact, or else an insulating interlayer in the form of a film or a further insulating layer is provided on the top sides of the thick-film heating resistors 143. After the bending round of the two halves towards each other, the strip is bent to form a cylindrical tube and is sealed off both on the inner side and on the outer side, for example by soldering, welding or by attaching a seal. The heating device 134 is then fastened on the pump bottom 22 or on the bottom section 18 corresponding to FIG. 1. In this case, the region which is open towards the side should not be located inside the pump chamber 24, or should not come into contact with the delivered fluid, but should project beyond this. This also facilitates the electrical connection. This is easily conceivable for the person skilled in the art.

The installation of the heating device 26 into a pump casing 13 corresponding to FIG. 1 is easily conceivable for the person skilled in the art, for example with annularly encompassing seals on the left and right. It is also conceivable that both a heating device 134 as a heated intermediate wall 34 and, in addition, a heating device 26 as a heated outside wall are used in a pump 11 according to FIG. 1. The construction cost may then be relatively high, however.