Pump and domestic appliance having such a pump

Abstract

A pump for a washing machine comprises a pump chamber with an inflow, an outflow and a pump-chamber base, also comprises an impeller for feeding water in the pump chamber, and further comprises a plurality of flow-directing vanes radially outside the impeller, the vanes being arranged in a fixed state and extending helically in the direction of the pump-chamber base. The pump is designed in the form of a centrifugal pump. According to a first embodiment, a pitch of the flow-directing vanes is 70% to 130% of the diameter of an outer wall of the pump chamber. According to a second embodiment, a radially outer region of the at least one flow-directing vane has arranged within it at least one guide blade, which is curved and projects axially away from the flow-directing vane. According to a third embodiment, a free end of the flow-directing vane extends to a distance of not more than 2 cm from the pump-chamber base.

Description

[0001] Pump and household appliance with such a pump

[0002] FIELD OF APPLICATION AND STATE OF THE ART

[0003] The invention relates to a pump, such as can be installed in particular in water-conducting household appliances such as dishwashers or washing machines. Furthermore, the invention relates to such a household appliance. The pump has a pump chamber with an impeller therein, with flow guide vanes extending radially outside the impeller with a helical pitch. The flow guide vanes are intended to optimize or influence the water flow in a pump chamber downstream of the impeller.

[0004] Such a pump is known from EP 2 495 444 A2, which also has such flow guide vanes. These extend from an outlet of the impeller upwards toward the inlet into a pump chamber, since an outlet from the pump chamber is also arranged or provided in this direction.

[0005] Another pump for a water-conducting household appliance is known from WO 2014 / 198 427 A1.

[0006] EP 4 215 759 A1 discloses a diffuser for a radial turbocompressor that extends annularly around a central axis. This diffuser has an inflow configured along a first section of the flow path for radial flow of a fluid during operation. The diffuser has vertical first guide vanes. The diffuser also has vertical second guide vanes that divide the diffuser into individual circumferential segments along a radial section. The second guide vanes extend in the direction of the flow path from a second leading edge to a second trailing edge.

[0007] TASK AND SOLUTION

[0008] The invention is based on the object of creating a pump mentioned above and a household appliance equipped with it, which can solve problems of the prior art and, in particular, make it possible to optimize the flow of water flowing out of or ejected from the impeller in a pump chamber of the pump, in particular to remove air bubbles from the pump chamber as quickly as possible after the pump has been running idle. Such air bubbles can remain in the pump chamber in a kind of tube or trail for a relatively long time, impairing the efficiency of the pump and, above all, generating unwanted noise.

[0009] This object is achieved by a pump having the features of claim 1 and by a household appliance provided therewith having the features of claim 15. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. Some of the features are described only for the pump or only for a household appliance provided with such a pump. However, they are intended to be able to apply independently and independently of one another to both such a pump and such a household appliance provided with such a pump. The wording of the claims is incorporated into the content of the description by express reference.

[0010] The pump has a pump chamber with an inlet, an outlet, and a pump chamber floor. At the pump chamber floor, the water direction can be reversed by either 180° relative to the longitudinal direction of the pump, or alternatively by 90° to the side, towards the outlet. The inlet is advantageously located centrally, as is usual for a centrifugal pump or an impeller pump. The outlet is advantageously located externally in the radial direction or runs parallel to the radial direction. An impeller rotates in the pump chamber, advantageously driven by a pump motor, to pump water in the pump chamber from the inlet to the outlet. The impeller runs above the pump chamber floor, advantageously at some distance from it, particularly advantageously between 20% and 120% of the diameter of an outer wall of the pump chamber.Furthermore, one or more flow guide vanes are provided, as explained at the beginning, which are arranged radially outside the impeller. This allows them to direct or channel water escaping or thrown out of the impeller as directly as possible in the desired direction and in the desired manner. The flow guide vanes are fixed and run in a known helical manner with a pitch that runs in the direction of rotation of the impeller towards the pump chamber floor. This allows the water escaping from the impeller to be efficiently and quickly directed to the pump chamber floor and thus to an outlet located close to the pump chamber floor. The pump is therefore designed as an impeller pump or centrifugal pump and draws water in centrally and axially through the inlet. It then pumps the water out radially through the outlet.

[0011] According to the invention, at least one of the following three features is implemented in the pump. The first of these features is a pitch of the at least one flow guide vane that is approximately in the range of the order of magnitude of the diameter of an outer wall of the pump chamber. Advantageously, the pitch of the flow guide vane is 70% to 130% of this diameter. Particularly advantageously, the pitch of the flow guide vane is approximately uniform, which can result in a uniform flow toward the pump chamber floor.

[0012] As a second feature, the invention can provide for at least one so-called guide vane to be arranged in a radially outer region of the at least one flow guide vane. This guide vane can be curved and extends in such a way that it protrudes axially from the flow guide vane, i.e. is attached to it or placed on it, so to speak. Such a guide vane can form a type of winglet and influence turbulence in the pumped water, in particular in such a way that the air bubbles mentioned above are removed. The guide vane can advantageously be thin, in particular at least on average have a thickness of between 70% and 120% of the flow guide vane. In a further embodiment of the invention, the guide vane can be curved or curved similarly to the pump chamber or with a curvature that would correspond to that of the pump chamber in this region if it were parallel or concentric.Such a guide vane can be particularly advantageously positioned radially outside the impeller and at the axial level of an impeller outlet, so that it can guide water flowing out of the impeller particularly well. If necessary, it can direct the water even more strongly toward the flow guide vane, thus giving the flowing water a particularly pronounced desired direction.

[0013] As a third feature, according to the invention, it can be provided that the pump chamber is arranged axially below the impeller such that the impeller is arranged or located between the pump chamber floor, on the one hand, and the inlet, on the other. A free end of the flow guide vane can extend to a maximum distance of 2 cm or a maximum of 20% of the diameter of the pump chamber from the said pump chamber floor, and advantageously end even closer to it. Contact with the pump chamber floor should, however, be avoided, so that a free end of one or each flow guide vane should be at least 1 mm away from the pump chamber floor.

[0014] Simply adding one of the three features mentioned above can improve the pump's efficiency. Adding two or even three of these features makes the pump even more efficient. A water-conducting household appliance equipped with one of these features can thus pump more efficiently and, for example, remove air from a previously empty pump chamber more quickly when water needs to be pumped again.

[0015] A pump can consist of a pumping section and an electric drive motor, thus forming the pump. The entire water flow is contained within the pumping section. The drive motor only rotates the impeller in the pump chamber.

[0016] In one embodiment of the invention, the at least one flow guide vane can be provided on a circumferential support ring or between the impeller and the pump chamber floor. The support ring is advantageously arranged substantially below the impeller so that it does not reach the impeller in the axial direction or even overlaps it. Preferably, the support ring can be arranged at a maximum distance of 10 mm below the impeller; in particular, it can be designed and / or arranged such that it directly adjoins it in the axial direction. A diameter of the support ring can preferably be between 80% and 120% or even between 90% and 110% of the diameter of the impeller. Particularly preferably, both have the same diameter, thus achieving the best possible water flow.

[0017] In a further embodiment of the invention, the at least one flow guide vane can be arranged axially and radially outside an outlet from the impeller, preferably extending to that outlet with a free end. Here, the flow guide vane is advantageously free, for example, free from a aforementioned support ring, and can, so to speak, tap and guide water directly from the impeller.

[0018] In an advantageous embodiment of the aforementioned first feature, the pitch of the at least one flow guide vane, advantageously of all flow guide vanes, can be 80% to 120% of the diameter of the outer wall of the pump chamber. Particularly advantageously, this can be 90% to 110%.

[0019] In one embodiment of the invention, a possible guide vane can have a leading edge that can run essentially parallel to the impeller's axis of rotation, in particular exactly parallel or slightly inclined. The water arrives at this leading edge first in its direction of circulation. In a further embodiment of the invention, an upper edge of the guide vane can run at an angle of between 80° or 100° to the leading edge, advantageously at approximately 90°. Alternatively, this upper edge can run parallel to the flow guide vane, i.e. run above it at a constant height. In yet another embodiment of the invention, a rear edge opposite the leading edge can run obliquely at an angle of between 10° and 50° to the leading edge. All of this preferably applies to a square guide vane. It rests with one edge on the flow guide vane or is connected to it, in particular formed integrally.

[0020] In a further development of the invention, a guide vane can not run exactly along a circular path around the impeller's rotational axis, but rather with a leading edge on a smaller circular path around the impeller's rotational axis than the trailing part, all the way to a rear edge. This allows the radial distance of the guide vane from the impeller's rotational axis to increase from the leading edge to the rear edge, thus increasing the distance between the guide vane and the impeller.

[0021] A guide vane can advantageously be arranged at the beginning of the flow guide vane or only a maximum of 10 mm behind it. Preferably, only a single guide vane is provided per flow guide vane.

[0022] Advantageously, a guide vane along the helical path of the flow guide vane can be only 10% to 35% of its length. In absolute length, this can be between 15 mm and 40 mm.

[0023] Regarding the third feature, a free end of the flow guide vane can preferably extend to a maximum distance of 1 cm, or 10% of the diameter of the pump chamber, from the pump chamber floor. The end of the flow guide vane should not be completely flush with the pump chamber floor, as this could cause hygiene problems and generate unwanted noise. Therefore, it is advantageous if the free end does not completely touch the pump chamber floor, or if a distance of 1 mm to 4 mm is still maintained.

[0024] In an advantageous embodiment, the outlet can lead out of the pump chamber above the pump chamber floor, particularly advantageously at a distance of 1 mm to 20 mm in the longitudinal direction of the pump. The impeller can preferably be arranged just behind the inlet, for example, connecting to the inlet internally.

[0025] The pump chamber can have an axial length that is between 70% and 200% of the diameter of the pump chamber, preferably between 80% and 160%. Thus, the pump chamber is neither particularly elongated nor compressed. In a further development of the invention, exactly two or exactly three flow guide vanes can be provided. This is considered sufficient for advantageous water flow. It is preferred if some or all of the flow guide vanes are of the same design. Additionally or alternatively, they can be arranged evenly around the impeller.

[0026] A household appliance according to the invention comprises a pump as described above and a treatment chamber with a chamber outlet therefrom, wherein the pump is arranged behind the chamber outlet. The household appliance is advantageously a dishwasher or a washing machine, i.e., a water-conducting household appliance.

[0027] These and other features emerge not only from the claims but also from the description and the drawings. The individual features may be implemented individually or in combination in an embodiment of the invention and in other fields, and may represent advantageous and individually protectable embodiments for which protection is claimed here. The division of the application into individual sections and subheadings does not limit the generality of the statements made therein.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Embodiments of the invention are illustrated schematically in the drawings and explained in more detail below. The drawings show:

[0030] Fig. 1 shows a pump according to the invention in an oblique view with a partially cut-open pump part including the pump chamber and a flow guide vane in the pump chamber,

[0031] Fig. 2 is a slightly rotated view of a pump similar to Fig. 1 with a guide vane at the front of each flow guide vane in the pump chamber,

[0032] Fig. 3 another view of the flow guide vane with guide wing,

[0033] Fig. 4 is a plan view of the pump from the direction of an inlet into the pump chamber with flow guide vane and guide vane on it, and

[0034] Fig. 5 is a view similar to Fig. 2 with a differently designed flow guide vane that extends to the bottom of a pump chamber.

[0035] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] Fig. 1 shows a pump 11 as a centrifugal pump, which has a conventional drive motor 13 at its rear end. The drive motor 13 is connected to a pump part 15, as is known per se from the prior art. The pump part 15 and the drive motor 13 thus form the pump 11, with the entire fluid or water flow being contained in the pump part 15.

[0037] An axial inlet 17 is provided in a pump cover 18 in the pump part 15. An outlet 19 extends from the bottom of the pump part 15, extending laterally in a direction parallel to the radial direction. This is known from the prior art, see, for example, the aforementioned WO 2014 / 198427 A1.

[0038] An annular pump chamber 21 extends within the pump part 15, beginning on the outside at the pump chamber cover 18 in the longitudinal direction of the pump 11 to a pump chamber base. The aforementioned drain 19 branches off to the outside at this pump chamber base, preferably being formed integrally. On the inside, the pump chamber 21 is bounded by an inner dome 24, which has a round or round-cylindrical cross-section and protrudes from the pump chamber base within the pump chamber base. On the outside, the pump chamber 21 is bounded by a pump chamber wall 25, which is advantageously inserted slightly above the pump chamber base. The pump chamber wall 25 is closed annular and can advantageously be made of metal and have a heating element for heating the water pumped in the pump 11. This is also known from the aforementioned prior art. The front end of the pump chamber wall 25 is attached to the pump cover 18 by means of a seal.

[0039] Below the inlet 17 is an impeller 28 with an impeller inlet 29. The impeller 28 has conventional impeller outlets 31 on the outside and impeller blades 32 on the inside. Here, for example, five impeller outlets 31 and five impeller blades 32 are provided. The impeller 28 rotates counterclockwise along the inlet 17, thereby expelling water drawn in to the inlet 17 outwards. This water then also circulates counterclockwise in the pump chamber 21 in paths along a helical line, namely to the pump chamber floor and then out to the outlet 19.

[0040] In order to transport the circulating water better, more strongly, or as desired, along the axial longitudinal direction of the pump 11 and towards the pump chamber floor 23, known flow guide vanes 36 are provided on a support ring 35. The support ring 35 is placed on the inner dome 24, and the impeller 28 is arranged directly above or adjacent to it. The diameter of the support ring 35 corresponds exactly to that of the inner dome 24 at the transition, and it can also correspond to the diameter of the impeller 28. Two flow guide vanes 36 are arranged on the outside of the support ring 35, with a pitch along the direction of circulation of the water in the pump chamber 21, away from the impeller 28 towards the pump chamber floor. The pitch of the flow guide vane 36 is selected such that it is approximately 70% to 130% of the diameter of the pump chamber wall 25, and in the present case, advantageously even corresponds approximately to this diameter. With such a gradient orAt such an angle, good water flow can be achieved. Furthermore, such a flow guide vane 36 can also very effectively remove residual air in the pump chamber after the pump 11 has been started, when the pump 11 has partially dried out and water is flowing in. If the gradient were smaller or significantly smaller, for example, if it were only 60% or less, the deflection of the water thrown out of the impeller 28 towards the pump chamber floor would no longer be as strong or the water would circulate for longer, and the efficiency of the pump 11 would be reduced. This is illustrated by the dashed line of such a flow guide vane, which has a significantly smaller gradient, namely only about 60% of the gradient compared to the flow guide vane 36.

[0041] If the gradient were significantly greater, for example, 30% to 50% greater, the deflection of the pumped water would be too strong, and the flow guide vane 36 would then act as too much of an obstruction to the flow. Furthermore, the pumped water would hit the pump chamber floor 23 at too obtuse an angle and might then no longer be able to be pumped out to the outlet 19 as effectively.

[0042] From Fig. 1, it can also be seen that the flow guide vane 36 extends approximately over the axial length of the support ring 35, or is only slightly shorter. Thus, it is stably constructed along its entire length due to its connection to the support ring.

[0043] While Fig. 1 shows the first aforementioned feature of the invention with the specific pitch, Figs. 2 to 4 show, according to the second aforementioned feature of the invention, how a guide vane 43 is molded onto each of the flow guide vanes 36 on a pump 11 with a support ring 35 in the pump chamber 21. The guide vane 43 is molded integrally onto the flow guide vane, advantageously produced together with the support ring 35 as a single plastic part by plastic injection molding. It can be seen that the guide vane 43 remains within a start 38, an end 39, and an outer edge 40 of the flow guide vane 36. With its rear end, it projects up to just before or to the outer edge 40, but can also be shorter or longer. The flow guide vane 36 has, as can be seen from Fig. 4, an approximately constant width and a straight edge at the start 38. The guide wing 43 has an essentially square shape.A leading edge 45 is straight and advantageously runs parallel to the longitudinal axis of the pump 11. An adjoining upper edge 46 is curved, viewed from the front, in keeping with the overall curved shape of the guide vane 43. The height of the guide vane 43 above the flow guide vane 36 can increase slightly from the leading edge 45 to a rear edge 47, so that the upper edge 46 can, under certain circumstances, run along a radial plane, for example, along a plane below which the impeller outlets 31 are located. The guide vane 43, designed as a type of winglet, ensures that water thrown out of the impeller 28 is directed as evenly as possible into the circular path of the pump chamber 21. Furthermore, it can break up any air bubbles or air bubble tubes that may be present, thus improving their removal from the pump chamber 21.

[0044] As can be seen from Fig. 3, the rear edge 47 slopes sharply downwards, particularly compared to the leading edge 45. The two edges can, for example, be at an angle of between 30° and 50° to each other. The guide vane 43 is also considerably shorter than the flow guide vane 36; for example, its length can be only 20% to 50% of that of the flow guide vane 36.

[0045] From the top view of Fig. 4, it can also be seen that the flow guide vane 36 extends around the support ring 35 with a largely constant width. This means that the outer edge 40 of the flow guide vane 36 has a constant distance from the pump chamber wall 25, whereby this distance is advantageously relatively small and can be between 1 mm and 8 mm.

[0046] The guide vane 43, on the other hand, is arranged with its leading edge 45 considerably closer to the impeller 28 than with its rear edge 47, i.e., radially further inward. The curved shape that can be seen may indeed correspond to that which a circle would have at this point, for example, halfway between the leading edge 45 and the rear edge 47. However, the guide vane 43 is slightly twisted outward with its end, so the distance of the rear edge 47 from the impeller 28 in the radial direction can be approximately 10% to 30% greater than that of the leading edge 45. The rear edge 47 can also end at the outer edge 40 of the flow guide vane 36, but this is not necessary. This ensures that the water thrown out of the impeller 28 is forced into a circular path, but not too strongly. This corresponds to the second feature of the invention mentioned at the beginning. A third feature of the invention is shown in Fig. 5.Here, by way of example, a single flow guide vane 36 is shown on the support ring 35, which, however, projects far beyond the support ring 35 in the longitudinal direction towards the pump chamber floor 23. One end 39 of the flow guide vane 36 ends only a few millimeters above the pump chamber floor 23. Here, the greatly extended flow guide vane 36 simply rests against the inner dome 24. Alternatively, the support ring 35 could also be extended very far in this direction, so that it could also extend just before the pump chamber floor 23. The pitch of this very long flow guide vane 36 can be approximately constant, in particular as defined in the aforementioned first feature of the invention. This flow guide vane 36 can ensure that water circulating in the pump chamber 21 is actually directed very quickly and very directly towards the pump chamber floor 23 or towards the pump chamber floor 23 so that it can then exit the pump 11 at the outlet 19.

[0047] In the pump 11 of Fig. 5, it is theoretically possible to provide two such very long flow guide vanes. Generally, however, only a single such long flow guide vane 36 is provided. Alternatively, one or two additional short flow guide vanes similar to those in Fig. 1 could also be provided. In a further alternative embodiment, at least one of the several flow guide vanes in the pump 11 of Fig. 5 can additionally have a guide vane similar to Figs. 2 to 4 at the beginning of a flow guide vane, i.e., radially outside the impeller 28.

Claims

Patent claims 1. A pump, in particular for household appliances such as dishwashers or washing machines, the pump comprising: a pump chamber with an inlet, an outlet, and a pump chamber floor, an impeller for pumping water in the pump chamber, the impeller extending above the pump chamber floor, one or more flow guide vanes radially outside the impeller, which are fixedly arranged and extend helically with a pitch extending in the direction of rotation of the impeller in a direction toward the pump chamber floor, the pump with the impeller being designed to function as a centrifugal pump with central axial suction of the water to be pumped through the inlet and radial outflow of the water to be pumped through the outlet, characterized in that: a) a pitch height of the at least one flow guide vane is 70% to 130% of the diameter of an outer wall of the pump chamber,and / or b) at least one guide vane is arranged in a radially outer region of the at least one flow guide vane, wherein the guide vane is curved and extends in the axial direction projecting from the flow guide vane, and / or c) the pump chamber is arranged in the axial direction below the impeller such that the impeller is arranged between the pump chamber floor and the inlet, wherein a free end of the flow guide vane extends to the pump chamber floor to a distance of a maximum of 2 cm or 20% of the diameter of the pump chamber.

2. Pump according to claim 1, characterized in that the at least one flow guide vane is provided on a circumferential support ring or between the impeller and the pump chamber floor, wherein the support ring is arranged substantially below the impeller, preferably at a distance of maximum 10 mm below the impeller, in particular arranged directly adjacent thereto.

3. Pump according to claim 2, characterized in that the diameter of the support ring is between 80% and 120% of the diameter of the impeller, preferably 90% to 110%.

4. Pump according to one of the preceding claims, characterized in that the at least one flow guide vane is arranged at the axial height and radially outside an outlet from the impeller, preferably with a free end projecting thereto.

5. Pump according to one of the preceding claims, characterized in that the pitch of the at least one flow guide vane is 80% to 120% of the diameter of the outer wall of the pump chamber, preferably 90% to 110%.

6. Pump according to one of the preceding claims, characterized in that a guide vane has a leading edge which runs substantially parallel to the axis of rotation of the impeller.

7. Pump according to claim 6, characterized in that an upper edge of the guide vane runs at an angle of between 80° or 100° to the front edge, wherein preferably an opposite rear edge of the guide vane runs obliquely at an angle of between 10° and 50° to the front edge.

8. Pump according to one of the preceding claims, characterized in that a guide vane does not run exactly along a circular path around an axis of rotation of the impeller, but runs with a front edge on a smaller circular path around the axis of rotation of the impeller than the following part up to a rear edge, wherein preferably a radial distance of the guide vane to the axis of rotation of the impeller becomes larger from the front edge to the rear edge.

9. Pump according to one of the preceding claims, characterized in that a guide vane along the helical course of the flow guide vane has only 10% to 35% of its length.

10. Pump according to one of the preceding claims, characterized in that a free end of the flow guide vane extends to a distance of maximum 1 cm or 10% of the diameter of the pump chamber from the pump chamber floor.

11. Pump according to one of the preceding claims, characterized in that the drain leads out of the pump chamber above the pump chamber floor.

12. Pump according to one of the preceding claims, characterized in that the impeller is arranged just behind the inlet and the pump chamber has a length in the axial direction which is between 70% and 200% of the diameter of the pump chamber, preferably between 80% and 160%.

13. Pump according to one of the preceding claims, characterized in that exactly two or exactly three flow guide vanes are provided.

14. Pump according to one of the preceding claims, characterized in that all flow guide vanes are of the same design and / or are arranged uniformly around the impeller.

15. Household appliance, preferably a dishwasher or washing machine, with a pump according to one of the preceding claims, characterized in that the household appliance has a treatment chamber with a chamber outlet therefrom, the pump being arranged behind the chamber outlet.

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