EP2481931A2 - Heating device for a pump and pump - Google Patents

Abstract

The device (122) has a heating element provided on a tubular carrier (124). The carrier exhibits a deformation (129) deviating from a continuous tubular form, where the deformation is a bend (131b) or a bead or collar-like deformation inwardly or outwardly. The deformation is provided at end regions of the carrier. The continuous tubular form of the carrier is a cylindrical tubular shape with straight cut ends. The deformation is rotationally symmetrical about a central longitudinal axis of the carrier. The heating element exhibits a distance to the deformation. An independent claim is also included for a pump comprising a pump housing and a pump chamber.

Description

Field of application and state of the art

The invention relates to a heating device for a pump, in particular for use as a water-conducting region of the pump or its pump chamber wall. Likewise, the invention relates to a pump, as it can be used in particular for household appliances such as dishwashers.

From the DE 102007017271 A1 In principle, a pump with a heater integrated on the outer wall is known. Since usually and also here the heating device has a metallic support and a pump housing is made of plastic, there is the difficulty of providing a sufficiently useable and permanently sealing gasket.

Task and solution

The invention has for its object to provide an aforementioned heating device and an aforementioned pump with which problems of the prior art can be avoided and in particular an advantageous construction for the heater with carrier can be achieved and a reliable seal can be created.

This object is achieved by a heating device with the features of claim 1 and by a pump having the features of claim 11. Advantageous and preferred embodiments of the invention are specified in further claims and are explained in more detail below. Some of the features are described only for a heater or only for the pump. However, they should be able to apply independently to both the heater and the pump. The wording of the claims is incorporated herein by express reference.

It is provided that the heating device is tubular and has a tubular support, on which at least one heating element is arranged or provided. Such a heating device can be used particularly advantageously as a water-conducting region of the pump or a pump chamber, that is also directly come into contact with the water or fluid conveyed by the pump. The carrier has at least one deformation deviating from the continuous tube shape, this continuous tube shape relating to the longitudinal direction of the carrier.

According to the invention a deformation is a bend or bead or collar-like deformation inwards or outwards or has such. Such deformation is provided on at least one of the end portions of the carrier, preferably a deformation at each of the end portions. Under certain circumstances, these deformations can then be of a similar design. This is especially true when looking at the carrier in longitudinal section. By such a deformation of the support with a bend in the form of a bead or a collar, an additional system for a seal between the heater or the support and the pump or a pump housing can be achieved, possibly also a position fixing a seal.

In an advantageous embodiment of the invention, the aforementioned continuous tube shape of the carrier may be a cylindrical tube shape, so the carrier be round cylindrical. Particularly advantageously, the ends of the carrier are cut straight. Thus, the carrier or the heater can be produced as easily as possible by automation. This therefore means that the deformations are preferably provided at the end regions of the carrier and the carrier otherwise is just round cylindrical. So it can be made relatively easily from a cylindrical metal tube.

In a further advantageous embodiment of the invention, the deformation is rotationally symmetrical about a longitudinal central axis of the carrier. As a result, on the one hand, the deformation can be made easier, for example by rolling, pressing and forging. Furthermore, this can be a certain independence from the rotational position of the carrier or the heater when installed in the pump or in the step of applying the heater can be achieved thereon. Above all, it is also easily possible for a substantially rotationally symmetrical carrier to use simply formed circumferential seals with a constant cross section. Furthermore, a deformation is advantageously produced without severing the material or cutting into the material. The wearer should therefore also have closed and continuously continuous inner and outer surfaces with the deformations. So it should not be generated holes in the carrier, which in turn mean more effort in the seal. Advantageously, several alternately bent bends can be provided, that is, virtually a bend or bend radially inward and then radially outward, ie with a different curvature, and vice versa. It is thus possible, in particular, for an end region of the carrier modified by a beading or deformation to have a narrow circumferential recess. It may have a width of a few mm, for example 1 mm to 4 mm. In or on this bead can then be arranged, for example, a sealing ring for sealing engagement with the pump housing. By positioning in the bead it is fixed in the longitudinal direction of the heater and can not twist. Furthermore, it is at least two points on the heater on or twice circumferentially line-shaped, so that overall a very good sealing effect can be achieved. In this regard, it does not matter whether the beading or deformation goes radially inward or radially outward, depending on whether a sealing action to the pump housing inward or outward is desired.

Furthermore, with such a circumferential beading or deformation, it is also possible not to arrange a circumferential annular seal within the bead, but rather opposite each other, so that an annular seal bears against a side wall or a sloping region of the bead. Then an effect similar to a bead can be achieved with respect to two investment points the seal, possibly in the manner of relatively broad lines or stripes. Only the axial securing of the seal against displacement is slightly worse than in the previously described embodiment. However, this can possibly be compensated by a corresponding system on a projection on the pump housing for the ring seal.

In a further embodiment of the invention, a deformation in the end region of the carrier can be formed radially outwardly in the manner of a step or in step shape. For this purpose, two rounded bends with alternating bend or bend can advantageously be provided, that is, with different curvature. As a result, the end edge of the carrier may have a larger diameter than the predominant central region of the carrier in the manner of a flange. In this case, it is considered advantageous to arrange an aforementioned ring seal within the expanded step-shaped deformation.

Alternatively, it is possible to form such a step-shaped deformation radially inward as a kind of constriction or reduction of the diameter of the end edge of the carrier. In this case, a sealing ring is advantageously arranged outside.

For a very simple application method of the at least one heating element on the carrier, it is advantageous if it has a distance from the deformations. In particular, in the case of deformations at both end regions, the heating element should be limited to a central region of the carrier. Depending on whether or not the heating element has been applied after deformation of the carrier, the distance to the deformations may be less or greater. For example, the distance may be at least 10% to 20% or even 30% of the length of the carrier. Particularly preferably, the carrier is deformed before the heating element is applied. Under certain circumstances, although the application process is somewhat more complicated. At the same time, however, the mechanically very demanding deformation be performed better and it can be avoided in any case, that the heating element is damaged.

In a further embodiment of the invention, a single heating element is advantageously provided. This extends substantially around the carrier and may beneficially occupy the largest area of the carrier or surface, in a central zone at a distance of about 10% to 20% or even 30% of the length of the carrier towards the end areas. Thus, the above-described distance to the deformations can be maintained and it can be avoided that a heating element is too close to a seal at the end regions or a connection to the pump housing, so that there is an undesirable or even inadmissible heating. In particular seals or sealing rings can be affected or damaged by heat, which should be avoided if possible. Thus, the heating in pumps with one of the DE 102007017271 A1 similar design principle are concentrated on a central region of the outer Pumpenkammerwandung where the heating of the pumped fluid is maximum.

In a further embodiment of the invention, it is possible to provide a smaller angle to the longitudinal center axis of the carrier in a deformation in the manner of a bead with two successive oblique regions lying closer to the undeformed central region of the support oblique region than the second oblique region. This can apply both for radially inwardly pointing and radially outwardly facing beads. In particular, in the case of radially inwardly pointing beads, it is possible for a holding projection of a pump housing lying in the vicinity to approach very closely with a similar running direction and, particularly if the sealing connection is in the vicinity of a pump base, a flow-favorable geometry is created. Because of such a smaller angle, namely, the fluid conveyed radially outwards in the region of the pump bottom from the impeller or impeller can be better redirected in the axial direction. Thus, in general, both the efficiency of the pump is higher and noise is lower. In such an embodiment of a deformation, a said sealing ring may advantageously be provided radially inwardly next to the deformation or adjacent to the second oblique region. Alternatively, it may run on the outside of the carrier in the bead. However, the first alternative has the advantage of a slightly larger distance to the heating element in the central region of the heater on together with lower thermal stress on the sealing ring.

In a further embodiment of the invention, projections or elevations may be provided in the region on the carrier on which abuts a circumferential sealing ring, advantageously in the manner of ribs. These should be formed circumferentially similar to the deformation, particularly advantageous rotationally symmetric. They can be generated when making the deformation, for example by rolling. These projections or ribs can then be pressed in the assembled state of the pump in the sealing ring or push in to protect against twisting or slipping of the sealing ring. As a rule, two to four such projections are considered sufficient. Under certain circumstances, such a projection can also be produced by a consciously relatively sharply defined edge of a deformation or bend against which the sealing ring bears, with a similar effect.

In a pump according to the invention, a prescribed heating device is mounted on a pump chamber wall or serves directly as a pump chamber wall. Advantageously, the heating is provided on an outer pump chamber wall, as is generally the case from the aforementioned DE 102007017271 A1 is known. Here, the fluid to be conveyed and heated flows mainly and laterally along the longest for a good heat transfer. Although it is possible to mount a said heater on an outer side of the pump housing or a corresponding Pumpenkammerwandung. This may even consist of sufficiently temperature-resistant plastic under certain circumstances. The heating element may then be provided both on the outside and on the inside of the carrier to abut directly on the outside of the pump chamber wall for optimum heat transfer. However, it is considered advantageous the heater itself form as Pumpenkammerwandung, so that the fluid to be conveyed flows along the inside of the heater or the carrier and, especially in the case of a carrier made of metal, ensures the best possible heat transfer.

As has already been explained, the heating device abuts against or is held by a retaining projection of the pump housing. For sealing purposes, a seal is advantageously provided therebetween, particularly advantageously a circumferential sealing ring of suitably suitable elastic material. It can also be provided that do not touch the heater and the pump housing or the retaining projection. In particular, when the deformation on at least one end portion of the heater is substantially radially outward and the carrier inner side by means of a sealing ring on the holding projection of the pump housing, which is located radially inside thereof, the retaining projection can cover the deformation. It can come close to a range of the heater without deformation at a small distance, namely radially within it. The radial distance between retaining projection and heating device can then be designed so that at an operating temperature of the pump, which is advantageously about 60 ° C to 80 ° C, which in this case is to be measured on the retaining projection, the radial distance between the heater and holding projection maximum 1 mm. He can be minimal at this operating temperature. Due to the material properties of a heater with a metallic carrier and a pump housing made of plastic, this distance is greater at lower temperatures of the pump. This can be achieved that with radially inner seal the contact pressure on the seal in the heated operation of the pump is maximum or even the sealing effect is maximum. Especially when a pump is mainly heated when conveying the fluid, this is advantageous.

Furthermore, a flow transition between the holding projection and the inside of the heating device can then be reduced by a small gap. Alternatively it can be provided that the deformation, although in turn radially is formed to the inside, a sealing ring but is arranged on the outside of the heating device, via which the heating device has a sealing engagement with an outer, circumferential retaining projection of the pump housing. Radially within this deformation is another circumferential inner retaining projection of the pump housing with a small radial distance to the inside of the deformation at about room temperature, ie without heating the pump. This radial distance as well as the material properties of the metallic carrier of the heating device and the pump housing made of plastic are designed so that the pump housing or the inner holding projection have expanded radially at an operating temperature of the pump of about 60 ° C to 80 ° C at the holding projection, that they just lie against the inside of the deformation and thus the distance or gap has disappeared. This can not only improve the sealing effect somewhat under certain circumstances, but can bring about yet another advantageous influencing of the flow conditions.

Another advantage of such inward or outward deformations of the heater is that so by investing a circumferential sealing ring this can be supported both in the radial direction and in the axial direction of the pump housing. As a result, fixing of the heating device in the pump housing is achieved, at least in the axial stop direction, without an end edge of the heating device having to rest directly on the pump housing or a seal. The production-related often provided sharp edges do not disturb so. By appropriate deformations including sealing rings on both end portions of the heater safe axial fixation in both directions is possible.

In an advantageous embodiment of the aforementioned embodiment with vanishing distance between inner retaining projection and heater at operating temperature of the pump in the heating mode can be provided that the inner retaining projection is provided with an obliquely outwardly directed surface. This can point in one direction, that of the first stage of the deformation of the diameter of the undeformed central region of the carrier radially inward corresponds. Thus, these two surfaces can therefore be approximately aligned for advantageous flow conditions in the pump chamber. Advantageously, a throat transition between the inside of the carrier in an undeformed region and the bevel of the first deformation may be generously rounded, so that the fluid flow can be well deflected from the radial direction in the axial direction to the outlet of the pump. In the second deformation, advantageously toward the end edge, a radius can be made rather small or the throat transition can be narrow here.

These and other features will become apparent from the claims and from the description and drawings, wherein the individual features each alone or more in the form of sub-combinations in an embodiment of the invention and in other fields 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.

Brief description of the drawings

Fig. 1

einen Schnitt durch eine erfindungsgemäße Pumpe mit einer rohrförmigen Heizeinrichtung,

Fig. 2

eine Vergrößerung eines Teilbereichs einer erfindungsgemäßen Heizeinrichtung entsprechend Fig. 1 im Querschnitt,

Fig. 3

zwei starke Vergrößerungen der Einbausituation der Heizeinrichtung entsprechend Fig. 2 in der Pumpe entsprechend Fig. 1 an der Dichtstelle zwischen Heizeinrichtung und Pumpe bei Raumtemperatur und bei Betriebstemperatur der Pumpe mit Beheizung,

Fig. 4

eine Abwandlung der Darstellung aus Fig. 3 mit innenliegendem Dichtring und anderen Dichtverhältnissen,

Fig. 5 bis

unterschiedliche Verformungen der Heizeinrichtung so-

Fig. 7

wie Ausbildungen des Übergangs zwischen Heizeinrichtung und Pumpengehäuse,

Fig. 8 und Fig. 9

speziell ausgebildete Verformungen an der Heizeinrichtung zur Verdrehsicherung eines Dichtrings,

Fig. 10 und Fig. 11

als Kröpfungen ausgeführte Verformungen der Heizeinrichtung mit innenliegender und außenliegender Ringdichtung.

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

Fig. 1

a section through a pump according to the invention with a tubular heating device,

Fig. 2

an enlargement of a portion of a heating device according to the invention accordingly Fig. 1 in cross section,

Fig. 3

two strong enlargements of the installation situation of the heater accordingly Fig. 2 in the pump accordingly Fig. 1 at the sealing point between the heating device and the pump at room temperature and at the operating temperature of the pump with heating,

Fig. 4

a modification of the presentation Fig. 3 with internal sealing ring and other sealing conditions,

Fig. 5 to

different deformations of the heating device

Fig. 7

such as formations of the transition between heating device and pump housing,

FIGS. 8 and 9

specially formed deformations on the heating device for preventing rotation of a sealing ring,

10 and FIG. 11

deformations of the heating device with internal and external ring seals executed as cranks.

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 advantageously used in a dishwasher or a washing machine. The pump 11 has in the left region a pump housing 12 with inlet 13, outlet 14 and pump chamber 16. Close to a pump chamber bottom 17, a conventional impeller 18 is arranged as a pump. 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 pump chamber 16 is circulated or runs around and finally exits from the pump 11 at the outlet 14.

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. The heating device 22 consists of a metallic tubular support 24 and a heating element 26 arranged on its outside. As can be seen, the heating device 22 seals the radially outer pump chamber wall via two circumferential sealing rings 23a and 23b Pump chamber 16 from and is sealingly connected to the pump housing 12.

In Fig. 2 is on average a heater 22 according to the invention accordingly Fig. 1 shown in magnification. From this, the cross-section of the carrier 24 can be seen better, which is designed to be rotationally symmetrical here, namely around the dot-dashed longitudinal central axis L accordingly Fig. 1 , The carrier 24 may have a thickness of 0.3 mm to a maximum of 2 mm, advantageously more in the range of 1 mm or slightly below.

On its outside, the carrier 24 has an insulating layer 25, for example made of glass or ceramic-like material. On this is the flat heating element 26. Regarding such a structure and the materials for carrier 24, insulating layer 25 and heating element 26 is inter alia on the EP 229928 A2 , the DE 3625087 A1 as well as the EP 885579 A1 directed. The heating element 26 may cover a large or predominant part of the area of a central region 28 of the carrier 24. This central region 28 is exactly round cylindrical and formed without deformation.

Deformations 29a and 29b respectively close to the middle region 28 on the left and right, in this case virtually constrictions inward or tapering of the tubular carrier 24. The deformations 29a and 29b are radially inwardly and adjoining by first bends 31a and 31b second bends 32a and 32b made in the opposite direction or with opposite curvature. At outer end edges 34a and 34b, the carrier 24 extends as in the original direction or parallel to the longitudinal central axis L, but with a reduced diameter or a kind of step inward in cross section.

In Fig. 3 is shown on the left for a temperature of about 20 ° C, ie room temperature, similar to a mounting situation Fig. 1 a heating device 122 with a carrier 124 and deformation 129 together with sealing ring 123b is arranged on the pump housing 112 or on the pump chamber bottom 117. The deformation 129 is formed with a first bend 131 b radially inward and a second bend 132 b again in the direction of the longitudinal central axis L as a diameter taper. Radially within the deformation 129 is an inner retaining projection 136b as a continuation of the pump chamber bottom 117. Radially outside the deformation 129 or the sealing ring 123b is an outer retaining projection 137b, against which the sealing ring, both in the radial and in the axial direction , The right-facing end edge 134b of the carrier 124 is spaced from the pump housing 112. Between the right end portion of the carrier 124 and the inner retaining projection 136b, a detectable gap 139 is given. This may be slightly less than 1 mm, for example about 0.5 mm.

Right in Fig. 3 the sealing point is shown at a temperature of 70 ° C in the pump chamber, so if the pumped fluid has been heated by the heater 122 to this temperature. The plastic in the pump chamber bottom 117 heats up to about 50 ° C, the support 124 to a higher temperature, in particular to 100 ° C or more. Due to the coefficients of thermal expansion determined by the materials, the plastic expands more strongly, and thus also the pump chamber bottom 117 in the radial direction. This causes, as shown by the dashed line, that although the outer diameter of the tubular heater 122 slightly widened in the region of the right deformation 129b, for example by 0.5 mm. At the same time, the pump chamber bottom 117 expands radially even without built-in heater 122, as shown by comparisons of the dotted lines on the example of the outer retaining projection 137b, for example, by almost 1 mm. This means, as in Fig. 3 It can also be seen on the right that the outer side of the inner holding projection 136b bears against the inside of the deformation 129b and thus the above-described gap of approximately 0.5 mm is closed. The dash-dotted lines illustrate this.

Because at the same time, as in Fig. 3 can be seen, the oblique region between the first bend 131 b and second bend 132 b has approximately in the direction of the pump chamber bottom 117, here is a streamlined and low-turbulence transition created. This is good for both improved pump delivery and noise. By reducing the gap between the heater and the bottom of the pump chamber, the sealing effect is improved, with a disappearance of the gap even significantly. Furthermore, although the sealing ring 123b is somewhat lengthened by the increase in diameter, it does not do much. However, radial compressive forces on it do not change significantly so that its preload is almost maintained.

In Fig. 4 left is in modification of Fig. 3 shown how the radially inner sealing ring 223b, a gap 239 between the inner retaining projection 236b of the pump chamber bottom 217 and heater 222 and first bend 231 b radially outward at a room temperature of about 20 ° C is relatively large. It can be for example 1 mm to 2 mm. Because of the radially inner sealing ring 223b no outer retaining projection is needed.

In the above-described warm operation right in Fig. 4 With temperatures of about 70 ° C of the fluid to be delivered, about 50 ° C of the pump chamber bottom 217 and the inner retaining projection 236b and a much hotter heater 222, the pump chamber floor 217 expands radially stronger again than the heater 222, this time virtually unhindered. As a result, the gap 239 is reduced, but it does not disappear, but remains with a gap width of about half, that is, for example, only about 1 mm. In this case, a streamlined arrangement is achieved in the warm state with a low-turbulence transition from the pump chamber bottom 217 to the heater 222 as the outer pump chamber wall. However, here the sealing ring 223b is pressed much more strongly in the radial direction, wherein the bias increases but also the sealing effect increases in relative terms. As long as the gap 239 does not completely disappear, heater 222 and pump housing are still acoustically decoupled, which is advantageous. At the same time, however, as from the comparison with Fig. 3 , Especially on the right side, it can be seen, the transition is not as aerodynamic and Wirbeltexungsarm as there.

In a further embodiment according to Fig. 5 For example, a deformation 329 has a third bend 333b in addition to a first bend 331b and a second bend 332b. A right-facing end edge 334b of the carrier 324 is again ring-like, but with the same diameter as the carrier 324. The deformation 329 thus creates a peripheral bead in the carrier 324 to the outside. The region of the bead is covered by an inner holding projection 336 of the pump housing, so that no turbulence area which unfavorably influences the flow of water is created. A sealing ring 323b is provided on the far right at the end of the support 324 in the region of the right third bend 333b outwardly on an outer retaining projection 337b.

Fig. 6 shows a further development of a similar deformation Fig. 5 , but with radially inner sealing ring 423b. The advantage here is that a transition from the pump chamber bottom 417 with inner retaining projection 436b may be formed in the oblique region between the first bend 431 b and second bend 432b in almost the same direction, which is particularly streamlined and low turbulence.

Furthermore, as with Fig. 5 , By the arrangement of the sealing ring 423b right of the deformation 429, the distance to the heating element, not shown here on the heater 422 maximum. This means that the sealing ring 423b is thermally stressed as little as possible, since it rests against the good heat-conductive metal of the carrier 424. The distance to the heating element is further increased by such a deformation with a triple bend, above all because the oblique area between the first bend 431 b and the second bend 432 b is additionally affected by cold fluid and therefore the support 424 is particularly strong in this area cools. The distance is also slightly larger compared to a deformation corresponding to 3 and 4 ,

Furthermore, in this case, the bead formed by the deformation 429 is not symmetrical. The bending angle at the first bend 431b is greater with respect to the perpendicular to the longitudinal central axis L than at the third bend 433b. The advantage of this is that the best possible streamlined adaptation to the pump chamber bottom 417 and the inner holding projection 436b can take place in the left oblique region. In the right oblique region, either a deformation that is easier to produce can be provided, or a seal-oriented design can be achieved by an almost right angle, in which the sealing ring 423b rests. It is in this embodiment as well as in Fig. 5 the end edge 434b of the carrier 424 is provided with the same diameter as a central region of the carrier 424.

A gap 439 between the pump chamber bottom 417 or inner retaining projection 436b and support 424 and second bend 432b can according to the explanations to the FIGS. 3 and 4 at operating temperature of the pump of about 70 ° C either still be present or disappear. For this purpose has been sufficiently carried out before.

In Fig. 7 is a variation of Fig. 6 shown. Although this is also a kind of deformation 529 provided in the manner of an inwardly directed bead. However, the left bevel region between first bend 531b and second bend 532b is much shorter than the right bevel region between second bend 532b and third bend 533b. As a result, on the one hand, the diameter of the end edge 534b is greater than in the middle region of the carrier 524. Furthermore, the said left oblique region is much shorter than at Fig. 6 whereby it can be achieved that the fluid flowing along from the pump chamber bottom 517 reaches the heated support 524 or the heating device 522 more quickly for heating. However, the sealing ring 523b is closer to a heating element of the heater 522 and thus thermally slightly more stressed.

In Fig. 8 a deformation 629 of the carrier 624 of the heater 622 is formed similarly as in Fig. 3 , only with an elongated rounding as the second

Bend 632b after the first bend 631 b. This rounding corresponds approximately to an outer concerns on the sealing ring 623b. On the radially outward-facing side, three rib-like rotationally symmetrical projections 640 are provided on the second bend 632b. These can, as indicated, push into the sealing ring 623b. On the one hand, they act as an additional sealing surface and thus improve the sealing effect. Furthermore, they form a torsion protection for the sealing ring 623b during axial and radial load changes, in particular during assembly of the pump and at different expansions during temperature changes, as has been described above. In practice, the rib-like projections 640 will press into the sealing ring 623b so far that it also abuts the areas of the second bend 632b therebetween. This additionally improves the sealing effect.

Furthermore, it is off Fig. 8 It can be seen that even a relatively generously rounded bend at the deformation 629 through the second bend 632b is both reasonably streamlined and gives a gap which is not too large. As previously explained, the rib-like protrusions 640 may be incorporated in forming the deformation 629, such as by rolling or forging.

In Fig. 9 For example, in a leaking region near an end edge 734b, a third bend 733b is provided radially outward and thus with the same curvature as the second bend 732b. As a result, two rib-like projections 740 are formed on the inside of the carrier 724 as a kind of edges, ie they are not additionally formed as in the illustration in FIG Fig. 8 but emerged by simply turning. They, too, can press something into the sealing ring 723b and both form an anti-twist protection for the sealing ring 723b and also act as additional sealing surfaces.

In Fig. 10 In a further modification, a simplified deformation 829 of the carrier 824 is shown with a single bend 831 b. The result is a kind of cranked carrier 824 with a widened offset, so that the end edge 834b does not point in the direction parallel to the longitudinal central axis L, but obliquely outward. Such deformation 829 can be achieved above all with less effort, since only a single bend is needed. By the oblique region to the right of the first bend 831 b, which is approximately at an angle of 45 ° to the longitudinal central axis L, the heater 822 is held in both the radial and in the axial direction of the sealing ring 823 b. Finally shows Fig. 11 a further variant of a deformation 929 in the manner of a crank, but with in contrast to Fig. 10 radially outward sealing ring 923b and obliquely inwardly facing end edge 934b. As can be clearly seen, the essential difference here is that, with this type of deformation, it is possible to very well absorb and continue the course of the pump chamber bottom 917 with the oblique region to the right of the first bend 931 b, which is particularly streamlined. This can also be further improved by precisely tuning the gap 939 to the thermal expansion behavior of plastic and metal, as explained above.

For the according Fig. 1 The left portion of the pump 11 may apply the same for the sealing point, as described above, in particular pump housing 12 and heater 22 may be formed symmetrically or accordingly. Alternatively, however, as in Fig. 1 As can be seen, training is easier because the aspects of flow control are less significant, since fluid flow does not have to be redirected near the outlet 14.

Claims (15)

A heating device for a pump, in particular for use as a water-conducting region of the pump or a pump chamber, wherein the heating device is tubular and has a tubular carrier and at least one heating element on the carrier, wherein the carrier has at least one deviating from the continuous tube shape deformation, characterized in that a deformation is a bend or crimp-like deformation inwardly or outwardly and at least one deformation is provided on one of the end regions of the carrier. Heating device according to claim 1, characterized in that the continuous tube shape of the carrier is a cylindrical tube shape, preferably with straight cut ends. Heating device according to claim 1 or 2, characterized in that the at least one deformation is provided at both end regions of the carrier, wherein it is in particular formed identically at both end regions. Heating device according to one of the preceding claims, characterized in that a deformation is formed rotationally symmetrical about a central longitudinal axis of the carrier. Heating device according to one of the preceding claims, characterized in that a deformation with a plurality of alternately bent bends is formed, wherein in particular a modified by a bead or deformation end portion of the carrier has a narrow circumferential recess, preferably with a width of 1 mm to 4mm. Heating device according to claim 5, characterized in that a deformation in the end region of the carrier is formed outwardly in a stepped shape, preferably with two rounded alternating bends, so that the end edge of the carrier has a larger diameter than the vast central region of the carrier. Heating device according to one of the preceding claims, characterized in that the at least one heating element has a distance from the deformations and in particular at deformations at both end regions, the heating element is limited to a central region of the carrier, preferably at a distance of at least 10% to 30% of the length the carrier to the end areas. Heating device according to one of the preceding claims, characterized in that a single heating element is provided, which extends substantially around the carrier and preferably occupies the largest area of the carrier or covered in a central zone at a distance of about 10% to 30% of Length of the carrier to the end areas. Heating device according to one of the preceding claims, characterized in that in a deformation in the manner of a bead having at least two successive oblique regions on the bead lying closer to the undeformed central region of the carrier first oblique region has a smaller angle to the longitudinal axis of the carrier than the second oblique region. Heating device according to one of the preceding claims, characterized in that rib-like projections are provided in the region for bearing a circumferential sealing ring on the support, in particular also circumferentially, for pressing into the sealing ring as protection against rotation or slippage of the sealing ring. Pump, in particular for household appliances such as dishwashers, with a pump housing and a pump chamber therein, in which an impeller rotates to convey fluid or water, characterized by a heater according to one of the preceding claims on a pump chamber wall or as Pumpenkammerwandung, in particular as outer Pumpenkammerwandung , Pump according to claim 11, characterized in that for sealing purposes, the heating device or the carrier at a radially inner or outer, overlapping in the longitudinal direction of the carrier support projection of the pump housing sealingly, in particular with the interposition of a circumferential sealing ring. A pump according to claim 11 or 12, characterized in that the deformation at at least one end portion of the support of the heater is substantially radially outwardly and the carrier inner side by means of a sealing ring on a retaining projection of the pump housing located radially inwardly thereof, wherein the projection to radially inside a support region without deformation opposite this with a small radial distance, wherein the small radial distance is such that at operating temperature of the pump of about 60 ° C to 80 ° C at the retaining projection of the pump housing, the radial distance is at most 1 mm or is minimal and at lower temperatures is greater. Pump according to claim 11 or 12, characterized in that the deformation is formed on at least one end portion of the carrier substantially radially inwardly and on the outside of the deformation, a circumferential sealing ring is arranged for sealing engagement with an outer, circumferential retaining projection of the pump housing, said radially within the deformation another circumferential inner Holding projection of the pump housing is provided with a small radial distance to the inside of the deformation at the operating temperature of the pump from about room temperature, said radial distance is formed so that at operating temperature of the pump or the pump housing or the retaining projection of about 60 ° C to 80 ° C by expansion of the pump housing disappears and the inner retaining projection rests against the inside of the deformation. A pump according to claim 14, characterized in that the radially inner retaining projection is provided with an obliquely outwardly directed surface which faces in a direction which corresponds to that of the first stage of deformation radially inwardly from the diameter of the undeformed central region of the support that the two surfaces are approximately aligned, wherein preferably the throat transition between the inside of the undeformed carrier and the chamfer of the first deformation is generously rounded and formed in the second deformation rather narrow or with a small radius.

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