METHODS AND APPARATUSES FOR A PUMP

Abstract

A radial pump for water has a drive motor, a pump chamber and an impeller revolving in the pump chamber. The impeller has a plurality of impeller blades which are designed, at least in regions, to be elastic and have a fixed mounting arranged in a region located near the impeller axis of rotation. They can bend elastically radially outward from this fixed mounting counter to a spring force.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application, filed under 35 U.S.C. §371, of International Application PCT/EP2012/062049, filed Jun. 22, 2012, which claims priority to German Application No. 10 2011 078 017.3, filed Jun. 22, 2011, both of which are hereby incorporated by reference in their entirety.

TECHNOLOGICAL FIELD

The invention relates to a pump for fluids, in particular to an impeller pump.

BACKGROUND

WO 2010/034488 A1 discloses a pump for fluids which is designed as what is known as an impeller pump or radial pump. This pump has the particular feature that it can convey both water and air, for example in a dishwashing machine. Thus, it can convey, on the one hand, water for the cleaning operation and, on the other hand, air for the drying operation. So that this can be done efficiently in each case, it is generally described that a conveyor of the pump has compressor blades which have an adjustable angle of incidence. Furthermore, the rotational speeds between the conveyance of water, on the one hand, and the conveyance of air, on the other hand, differ considerably from one another and in the first case are markedly lower.

BRIEF SUMMARY

The object on which the invention is based is to provide an initially mentioned pump, by means of which the problems of the prior art can be solved and, in particular, an advantageous possibility can be afforded of using such a pump with an impeller or compressor universally and in each case very efficiently.

This object is achieved by means of a pump. Advantageous and preferred refinements of the invention are the subject matter of the further claims and are explained in more detail below. The wording of the claims is made the content of the description by explicit reference.

There is provision whereby the pump is designed as a radial pump or as an impeller pump, with a rotating compressor or impeller revolving in a pump chamber. This compressor or impeller is designated hereafter as an impeller which has a plurality of impeller blades which are designed, at least in regions, to be flexible or elastic or be movable. In this case, they have a fixed mounting arranged near the impeller axis of rotation or in a radially inner region. In particular, here, they are firmly connected to the impeller, without a rotary joint having an axis or the like, by means of a material connection or adhesive bond or by being produced in one piece. The impeller blades can be bent or are movable radially outward from this fixed mounting, specifically counter to an antagonistic force or spring force. This spring force serves for pressing the impeller blades into a basic position which is explained in more detail hereafter.

This basic position is advantageously the position in which the pump conveys a medium of very low density, preferably air, and may therefore also be designated as the air position. This therefore means that the abovementioned spring force attempts to press the impeller blades into the air position. In general, bending or movement of the impeller blades can then take place along the direction of rotation, especially advantageously in the direction of rotation of the impeller caused by the spring force. This therefore means that, in the normal state or in the abovementioned basic position, the impeller blades are in the air position, which is to be ensured by the spring force and in which the impeller blades are, as it were, set out to the maximum extent.

Alternatively, however, it is also possible that the basic position is the position at which the pump conveys a medium of high density, preferably liquid or water, and may therefore also be designated as the water position. This therefore means that the abovementioned spring force attempts to press the impeller blades into the water position, that is to say opposite to the direction of rotation, in which case the impeller blades are, as it were, set out to only a minimum extent or are bent in to the maximum extent.

In an advantageous refinement of the invention, the spring force is generated as a result of the elastic properties of the material of the impeller blade itself, that is to say inherently by the impeller blade itself For this purpose, the impeller blade is advantageously composed of an appropriate plastic, for example of an elastomer having the desired elastic properties. Attention must in this case also be given to the shape of the impeller blade.

There is preferably provision whereby the impeller blades are curved monotonically radially outward from the abovementioned fixed mounting. This applies especially preferably to their entire course, in which case the curvature may vary slightly along the course, but their direction of curvature should not vary. The curvature is advantageously strictly monotonic and/or approximately uniform. In this case, as is customary per se for such impeller pumps, a curvature runs radially outward opposite to the direction of rotation. The curvature should be present in all positions and therefore also in the basic position or air position, even if it may be markedly lower here than in another position, for example for conveying a fluid of higher density, for example water, as is explained in more detail hereafter.

An angle of the impeller blades to the radial direction may amount, in the state bent inward to the maximum extent, to slightly less than 90°, preferably to between 70° and 80°. This applies, above all, to the outer region of the impeller blades on account of the abovementioned curvature. In the radially inner region of the impeller blades, this angle may be considerably smaller, for example may amount to only about half or 30° to 45°.

When the impeller blades are in the state bent outward to the maximum extent, that is to say in the abovementioned air position, their angle to the radial direction may amount to slightly more than 90°, preferably to between 100° and 110°. This is precisely because, above all, in this state which corresponds to the air position, the impeller blades bend when they are set out to a greater extent and they therefore change their course over their length.

Admittedly, the abovementioned fixed mounting may to a certain extent enable an impeller blade to rotate in the manner of a turn-off However, it should, in itself, be essentially a torque-resistant mounting, that is to say not a rotary joint. This may be achieved, for example, in that the impeller blade is secured in a specific region of its length, preferably near the inner end, so as to have a certain longitudinal portion there. This securing may take place, for example, in that the impeller blade is firmly connected, by adhesive bonding or by being produced in one piece, to an impeller bottom disk or impeller cover disk. Although a portion adjoining the latter radially outward is then immovable per se, by contrast to the impeller blade projecting from it already extends radially outward over its length from the longitudinal portion. Such a longitudinal portion may have a length of, for example, 0.5 cm to 2 cm or may amount to 5% to 30% of the overall length, this being considered to be an adequate fastening of the impeller blade and being sufficient for stipulating a certain shape.

Alternatively, it is possible, in actual fact, to provide a kind of axis of rotation for the impeller blade in the radially inner region or on the impeller. The disadvantage of this, however, is that the abovementioned spring force which attempts to press the impeller blades into a specific position, advantageously into one of the possible end positions, has to be generated via separate means. Furthermore, it is then not so easily possible for the impeller blades to bend over their length or to straighten somewhat under corresponding operating conditions. To be precise, in the case of a torque-resistant mounting of the impeller blade, the spring force can at the same time be achieved by means of the material properties of the impeller blade, as initially mentioned, and therefore by a more uniform curvature.

In an advantageously simple refinement of the invention, the impeller blades run radially outward from the mounting without further guidance, that is to say are free. This means that an impeller for such a pump can be produced in a simple way with low susceptibility to faults.

Alternatively to this, a guide of the impeller blades in the direction along the impeller axis of rotation may be provided. This guide should be provided radially outside the fastening of the impeller blade to the impeller, in particular as far to the outside as possible on the impeller or one of its impeller disks. It is possible that the impeller blade is arranged or projects between the impeller bottom disk and impeller cover disk and can execute a virtually guided movement along the direction of rotation if it has a certain thickness and therefore cannot be twisted or tilted in its longitudinal direction. In this case, it may come to bear against the disks or have only a very slight clearance with respect to these, so that it cannot also be deflected in an undesirable way in the direction along the impeller axis of rotation.

A special possibility for guiding an impeller blade may be achieved in that the impeller blade has an elongate continuous longitudinal slot which is provided, at least in a radially outer region, in a direction parallel to the impeller axis of rotation. In this longitudinal slot, a sliding element, in particular a pin-like sliding element, may be arranged. This may, on the one hand, be movable in a slot in the impeller bottom disk and/or the impeller cover disk, advantageously along the circumferential direction, that is to say on an especially advantageously circular path. At the same time, the pin-like sliding element may be displaceable in the longitudinal slot in the impeller blade and then, in the case of the increasing or decreasing curvature of the latter, can move both in the longitudinal slot of the impeller blade and in the slot of the impeller disks, because, of course, the impeller blade is connected fixedly in terms of rotation to the impeller in the radially inner region.

The provision of such a sliding element may, on the one hand, give rise to a certain additional sluggishness, which may sometimes be desirable, when the impeller blade bends up or bends in. Furthermore, tilting or twisting of the impeller blade along its longitudinal extent can be avoided. Finally, limit stops may thus be provided for the movement of the impeller blade, in particular for it to bend up and bend in.

While the above-described air position of the impeller blade corresponds to a minimally curved state and the impeller blade in this case protrudes as far as possible out of the impeller and is close to a radial direction with a relatively straight course, the impeller blade, when in a water position curved to a maximum extent, may extend laterally out of the impeller less far or even not at all. Furthermore, it may in this case be held by an additionally provided stop or may bear against this. This may, in particular, be counter to the initially mentioned spring force, since, when water or another fluid of high density is conveyed, the impeller blades are automatically curved to a greater extent opposite the direction of rotation and are pressed inward into the impeller. The abovementioned spring force may therefore, of course, also be provided and then, precisely when fluid of low density is conveyed, again presses them outward into the air position, as it is known.

Alternatively, there may also be provision whereby a spring force presses the impeller blades into the abovementioned water position, but not particularly strongly. If a fluid of lower density is to be conveyed and the impeller is to assume the air position for this purpose, it rotates at considerably higher rotational speed. Considerably higher centrifugal forces thereby act upon the impeller blades, and these are set further up or bend up, even counter to the abovementioned inwardly pressing spring force, and project further out of the impeller and thus assume the air position. This may also be reinforced in that regions of larger mass or even additional weights are provided on the outer regions of the impellers.

In a further refinement of the invention, an abovementioned inner spring force of the impeller blade may be afforded over a substantial part of its length, advantageously over its entire length. It is possible to manufacture the entire impeller blade from a single material, and it may also have essentially a constant cross section over its length. Easier bending or specific spring properties of an impeller blade may be set both by the choice of its production material and by the cross section, for example also by recesses being provided, in particular along the impeller blade.

When the impeller blade projects out of the impeller in the air position, this may take place, for example, with about 20% to 50% of its length. In this case, a sufficient amount of room must be provided radially in the pump chamber of the pump. In the state curved to the maximum extent, in particular in the water position, an impeller blade should project out of the impeller only slightly or not at all.

This and further features may be gathered not only from the claims, but also from the description and drawings, while the individual features may be implemented in each case independently or severally in the form of subcombinations in an embodiment of the invention and in other fields and may constitute advantageous and independently patentable versions for which protection is claimed here. The subdivision of the application into subheadings and individual sections does not restrict the general validity of the statements made under these.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

An exemplary embodiment of the invention is illustrated diagrammatically in the drawings and is explained in more detail hereafter. In the drawings:

FIG. 1 shows a diagrammatic illustration of a pump with an impeller according to the invention,

FIG. 2 shows an oblique view of the impeller with impeller blades both in an air position and in a water position,

FIG. 3 shows a sectional illustration through the impeller from FIG. 2 with a more detailed illustration of the course of the impeller blades in the air position and in the water position, and

FIG. 4 shows a top view of a modification of the impeller blades, similar to FIG. 3, with solid impeller blades without longitudinal slots.

DETAILED DESCRIPTION

FIG. 1 illustrates in a highly diagrammatic illustration a pump arrangement 11 according to the invention. This pump arrangement 11 is installed in a water-carrying domestic electrical appliance, in particular into a dishwasher or washing machine, advantageously under the washing chamber of the latter.

The pump arrangement 11 has a pump 12 which has a pump casing 13 and a motor 15, the motor axle 16 of which extends into the pump casing 13 and carries a conveyor 18 which rotates inside the pump casing 13 in a pump chamber 19. The connection of the pump casing 13 and motor 15 is advantageously fixed, for example by means of a releasable screw connection.

In the version illustrated here, the conveyor 18 is advantageously of conventional design and corresponds, for example, to a conveyor, such as is known from DE 19903951 A1, to which express reference is made in this regard. Furthermore, here too, the illustration of the dimension of the pump casing 13 and of the other components is not true to scale.

The pump casing 13 or pump chamber 19 has a central and axial pump inlet 21. Furthermore, a pump outlet 23 is provided, which is arranged laterally and radially. A heating system 28 runs inside the pump chamber 19 and has heating connections 29 which are led out of the pump casing 13. The heating system 28 illustrated is of an essentially cylinder-like design, so as to run around near to or on the wall of the pump chamber 19, with the exception of an appropriate interruption, not illustrated, for the pump outlet 23. The heating system may be an initially mentioned thick-film heating system, heating elements being arranged on at least one of its sides, advantageously on the outside, if appropriate also on the other or on both sides.

FIG. 2 shows an impeller 18 in an enlarged oblique illustration from above. It can be seen here that the impeller 18 has an impeller bottom disk 30 and an impeller cover disk 32, as is known per se. The impeller bottom disk 30 is of essentially flat form and the impeller cover disk 32 is designed to rise, as can be seen in the side illustration from FIG. 1. An intake port 33 is located in the middle of the impeller cover disk 32, as is known per se. The above-described motor axle 16 is fastened in the impeller bottom disk 30. The direction of rotation of the impeller 18 in FIG. 2 is counterclockwise.

The impeller 18 has five impeller blades 35 which are illustrated in FIG. 2, on the one hand, as impeller blades 35 in a state bent out to the maximum extent. This state corresponds to an initially mentioned air position of the impeller blades 35. On the other hand, however, the impeller blades are also illustrated, at least in the lower region, by reference symbol 35′. It becomes clear, in conjunction with FIG. 3, that, here, these impeller blades 35′ are in the water position and are bent as far as possible inward or curved to the maximum extent. In this case, on account of a stop, not illustrated here, they reach only insignificantly beyond the diameter of the impeller 18 or of the impeller disk 30, 32. In this case, care must be taken, in the design of the impeller 18 or of the overall pump 12, in particular with the heating system 28, to ensure that the impeller blades 35, in the position bent out to the maximum extent according to FIG. 2, do not brush on the inside against the pump casing 13 or heating system 28.

FIG. 3 illustrates in a slight enlargement how the impeller blades 35 are designed, without illustrating the impeller cover disk 32. In the radially inner region or at the radially inner end, they have a fastening region 37 in which they are firmly connected over a certain length to the impeller bottom disk 30. This firm connection may, on the one hand, be produced in one piece and, on the other hand, be a firm bonding or other stable and permanent fastening, for example by means of a positive connection, such as plugging in or the like. The impeller blade 35 extends outward from the fastening region 37, illustrating by hatching, and is in this case no longer connected to the impeller bottom disk 30. The free region of the impeller blade 35 may in this case have a very slight clearance with respect to the impeller bottom disk 30, in particular also with respect to the impeller cover disk 32, above all in the radially outer region, for example in the amount of a few tenths of a millimeter.

As regards the impeller blade 35, a shaping or stipulated curvature, as in the air position, is illustrated by reference symbol 35. This means that the impeller blade 35 is in the air position, without being influenced by external force. When it is bent in the direction of rotation of the impeller 18 counterclockwise opposite to this direction of rotation, that is to say to the right, it assumes the more highly curved water position 35′. The curvature illustrated arises, in particular, when the impeller 18 conveys water in the pump 12 and the water resistance or the considerably higher force necessary for this curves the impeller blade 35 to a greater extent. As soon as this higher force lapses, the impeller blade 35 moves back into the air position again as the impeller blade 35 due to its intrinsic spring force.

As a guide device for guiding the impeller blade 35, there is provided in the impeller bottom disk 30 a slot 39 which extends over a region near the outer circumference and at the same time reaches virtually to the impeller blade 35 in the air position and to the impeller blade 35′ in the water position. A pin-like sliding element 40 is mounted in the slot 39 and can be moved along the slot 39. Advantageously, a corresponding slot is located above the slot 39 on the underside of the impeller cover disk 32, so that the sliding element is secured on both sides. For safe and tilt-free guidance, the sliding element 40 may have a kind of elongate carriage body slightly curved correspondingly to the slot 39 and having a pin, for guidance in one or in both slots of the impeller disks 30 and 32, two carriage bodies then being connected by the pin. This pin of the sliding element 40 runs, as illustrated, in a longitudinal slot 36 in the impeller blades 35. The slots 36 and 39 may in this case, together with a sliding element 40, be designed such that, in the air position of the impeller blade 35, the sliding element 40 is located at the very bottom of the slot 39 and as far radially inward as possible on the longitudinal slot 36 of the impeller blade 35. In the water position of the impeller blade 35′, the sliding element 40 is located at the very top of the slot 39 and as far to the outside as possible on the longitudinal slot 36. This therefore defines the state curved to the maximum extent of the impeller blade 35′. In possible intermediate positions, the sliding element 40, on the one hand, defines a certain guidance or stipulated shape of the impeller blade 35. Furthermore, as illustrated in FIG. 3, it may, above all, represent as it were limit stops for the water position, on the one hand, and the air position, on the other hand. To be precise, the impeller blade 35 cannot be bent more sharply either in the direction of rotation or opposite to the direction of rotation of the impeller 18.

Furthermore, regarding the two positions according to FIG. 3, it must be said that, because of the lever arm resulting from force being applied to the impeller blade, the bend or curvature of the latter mainly takes place in the inner region near the fastening region 37. The exact form of the curvature or the course of the curvature can be influenced by various adjustable material properties of the impeller blade 35 and also by shaping, for example by the longitudinal slots 36 or the like, for example also by the cross section changing along the longitudinal course.

For the impeller blades 35, care must also be taken to ensure that, as can be seen from FIG. 1, they should, on the one hand, have a shape such that they run essentially near to the impeller bottom disk 30 and impeller cover disk 32, specifically in both positions. For this purpose, however, care should then be taken to ensure that the clearance between the two impeller disks 30 and 32 in the region in which the impeller blades 35 curve in and out between them is such that the movement of the impeller blades is not impaired.

Alternatively to a curvature, stipulated virtually by shaping, of the impeller blade 35 into the air position according to FIG. 3 with minimum curvature, there could also be provision whereby, in the normal or nonloaded state, the impeller blade 35′ assumes the water position and is therefore curved to the maximum extent. If air is to be conveyed by the pump 12, the rotational speed at the motor 15 is greatly increased, for example doubled or tripled, which greatly increases the centrifugal forces acting upon the impeller blades 35 and may in this case have the effect that, according to FIG. 3, they bend or are set up into the air position to a greater extent. This may sometimes also be reinforced in that regions of higher mass are provided or even additional weights are attached in the region of the outer free ends of the impeller blades 35. If water is then conveyed again in the pump 12 with a lower rotational speed, the impeller blades 35 move back into the highly curved water position again, on the one hand, because of the diminishing centrifugal force and, on the other hand, on account of the stipulated shape.

FIG. 4 illustrates, in a modification for an impeller 118, how the impeller blades 135 arranged on an impeller bottom disk 130 may be designed to be solid or without the longitudinal slots according to FIG. 3. This therefore means that the impeller blades 135 have no guidance of their movement between the minimally curved air position set out as far as possible, on the one hand, and the water position curved to the maximum extent to the right, as impeller blades 135′. Only a first stop 141 for the air position is provided on the impeller bottom disk 130. Similarly, a second stop 142 for the water position is provided on the impeller bottom disk 130. These stops 141 and 142 have the effect that the movement or curvature of the impeller blade 135 is limited in a similar way to that by the sliding element 40, together with the slot 39, according to FIG. 3.

This design of the impeller disks 130 and 132 and of the impeller blades 135 themselves is somewhat simpler than according to FIG. 3. The stops 141 and 142 may either extend only a little way over the impeller bottom disk 130, in order to bring about water resistance or give rise to turbulences as little as possible. Alternatively, they may also run over the substantial height or overall height of the impeller blades 135, in particular toward the opposite impeller cover disk 132. Thus, on the one hand, they ensure good distortion-free bearing contact of the impeller blades 135. On the other hand, they can also serve for connecting the two impeller disks 130 and 132 to one another.

As regards a possible preshaping or precurving of the guide blades of the exemplary embodiment of FIG. 4, the same can be said as for FIG. 3, that is to say they have the same possibilities. The guidance, omitted in the exemplary embodiment according to FIG. 4, by means of a sliding element and slot changes nothing in that regard.

Claims

1. A pump for fluids, with a drive motor, with a pump chamber and with an impeller revolving or compressor rotating in said pump chamber, said pump being designed as a radial pump, said impeller having a plurality of impeller blades, wherein said impeller blades are designed, at least in some regions, to be flexible or elastic or movable and have a fixed mounting arranged in a region located near the impeller axis of rotation, said impeller blades being bendable or movable radially outward from said fixed mounting counter to a spring force.

2. The pump as claimed in claim 1, wherein said impeller blades are bendable or movable in a direction of rotation of said impeller counter to said spring force.

3. The pump as claimed in claim 1, wherein said spring force is afforded inherently by elastic properties of a material of said impeller blade.

4. The pump as claimed in claim 1, wherein said impeller blades are curved monotonically radially outward from said fixed mounting.

5. The pump as claimed in claim 4, wherein said impeller blades are curved monotonically radially outward from said fixed mounting along their entire course.

6. The pump as claimed in claim 4, wherein a curvature runs radially outward opposite to a direction of rotation.

7. The pump as claimed in claim 4, wherein an angle of said impeller blades to a radial direction in a state bent inward to a maximum extent amounts to less than 90°.

8. The pump as claimed in claim 7, wherein said angle of said impeller blades to said radial direction in said state bent inward to said maximum extent amounts to between 70° and 80°.

9. The pump as claimed in claim 4, wherein an angle of said impeller blades to a radial direction in a state bent outward to a maximum extent amounts to more than 90°.

10. The pump as claimed in claim 9, wherein said angle of said impeller blades to said radial direction in said state bent outward to said maximum extent amounts to between 100° and 110°.

11. The pump as claimed in claim 1, wherein said fixed mounting is a torque-resistant mounting.

12. The pump as claimed in claim 1, wherein said fixed mounting of said impeller blades occupies a radially innermost region of said impeller blades or is arranged there.

13. The pump as claimed in claim 12, wherein said fixed mounting of said impeller blades occupies said radially innermost region of said impeller blades or is arranged there as a torque-resistant mounting with securing of a longitudinal portion of said impeller blades of at least 0.5 cm.

14. The pump as claimed in claim 1, wherein said impeller blades run from a torque-resistant mounting radially outward freely without further guidance.

15. The pump as claimed in claim 1, wherein, radially outside a fastening of said impeller blades, a guide of said impeller blades in a direction along said impeller axis of rotation is provided.

16. The pump as claimed in claim 15, wherein said guide is provided by an impeller bottom disk and an impeller cover disk, between which said impeller blades are arranged or can project.

17. The pump as claimed in claim 15, wherein an impeller blade has an elongate continuous longitudinal slot in a radially outer region in a direction parallel to said impeller axis of rotation, there being arranged in said elongate continuous longitudinal slot a sliding element, which is movable along a circumferential direction in a slot at least in said impeller bottom disk or in said impeller cover disk and which at the same time is displaceable in said elongate continuous longitudinal slot in said impeller blade.

18. The pump as claimed in claim 17, wherein said sliding element is a pin-like sliding element.

19. The pump as claimed in claim 1, wherein said impeller blade has a water position curved to a maximum extent for conveyance of water or other liquid.

20. The pump as claimed in claim 19, wherein, in said water position, said impeller blade bears against a stop as a result of force exerted by the conveyed water.

21. The pump as claimed in claim 1, wherein, in a minimally curved state, said impeller blade assumes an air position and at the same time is loaded by spring force.

22. The pump as claimed in claim 20, wherein, in said air position, said impeller blade bears against a stop.

23. The pump as claimed in claim 20, wherein a spring force is generated by specific elastic properties of said impeller blade.

24. The pump as claimed in claim 1, wherein an inner spring force of said impeller blade acts opposite to a direction of rotation.

25. The pump as claimed in claim 1, wherein an inner spring force of said impeller blade is afforded over a substantial part of its length by correspondingly elastic or flexible properties of said impeller blade.

26. The pump as claimed in claim 1, wherein an entire impeller blade is composed of a single material and also has essentially a constant cross section over its length.

27. The pump as claimed in claim 1, wherein, in a minimally curved state, said impeller blades project out of said impeller or between an impeller bottom disk and an impeller cover disk.