EP2150165B1 - Pump having a heating device - Google Patents

Description

The present invention relates to a pump, in particular for dishwashers, comprising a housing comprising a housing bottom, a housing cover and a heater arranged therebetween for heating a rinsing liquid, which forms an annular side wall of the housing, with an arranged in the housing impeller, with respect to the Rotary axis of the impeller in the housing cover axially arranged suction nozzle and with a discharge nozzle.

From the DE 201 07 363 U1 Such a pump is known for dishwashers. A disadvantage of this pump is the vertical arrangement of the pressure nozzle relative to the axially arranged suction nozzle. It protrudes beyond the cylindrical basic shape of the pump, resulting in a larger expansion of the pump in the radial direction. The pump requires more installation space and reduces the useful volume of the dishwasher. Another disadvantage of this pump is the low heating surface of the annular heater, which is also broken by the discharge nozzle. In order to heat the rinsing liquid in a short time, a high heating power must be provided with correspondingly high temperatures of the heater. This can lead to problems such as premature aging, in particular at the connection points of the heating device to the adjacent plastic parts, on which sealing elements may also be present. The result is porosity of the sealing material or the adjacent plastic parts and thus leaks in the devices.

Furthermore, from the GB 1 398 148 a pumping device, in which two pumps are combined to form a unit and driven by a common motor. The pump device described can replace a conventional circulation pump and a conventional waste water pump of a dishwasher, whereby space can be saved.

The invention has for its object to provide a simple and inexpensive pump of the type mentioned, which has smaller external dimensions, in particular in the radial direction while avoiding the aforementioned disadvantages.

According to the invention this object is achieved in a pump of the type mentioned above in that the discharge nozzle is arranged in the housing cover, wherein a longitudinal axis of the suction nozzle is arranged at an acute angle to the longitudinal axis of the discharge nozzle. The arrangement of the pressure port in the cover allows a reduction in the outer dimensions of the pump in the radial direction relative to the longitudinal axis thereof. The installation space, in particular the required installation height for the pump is reduced. With a horizontal installation of the pump below the washing container with the longitudinal axis of the pump parallel to the bottom of the washing, valuable installation height can be saved. As a result, the useful volume of the washing container can be increased.

It is envisaged that a longitudinal axis of the suction nozzle is arranged at an acute angle to the longitudinal axis of the pressure nozzle in addition, the suction can be connected via very short or even without connecting elements directly with a drain at the bottom of the washing and the discharge nozzle with a supply to the spray system. In the arrangement of two corresponding with the suction and the discharge nozzle connections at the bottom, can be dispensed with additional parts, such as hoses and their attachment means.

The arrangement of suction nozzle and discharge nozzle in the lid according to the invention allows a simple structure of the heater, namely with a tube with a closed circular cross-section. Elaborate production engineering forming or processing steps for an opening in the heater can thus be omitted. It is thus largely produced using standard parts. Incidentally, the rinsing liquid can be heated in a breakthrough-free tube more uniform than in a ring with openings, because a large-scale undisturbed flow of water along the entire tube surface area sets.

Such a tube is also easily replaceable. With a tubular side wall also a structurally simple construction of the housing of the pump is also possible, wherein the housing cover and the housing bottom made of plastic and the tubular side wall made of metal can be made separately. The use of plastic allows in addition to a cost-effective production of complex geometries the housing cover and the housing bottom also a reduction of the total weight of the pump. Plastic is also a poor conductor of heat, so that the transport of the heated rinsing fluid in the pump can be done almost energy loss. The tube of the heater is advantageously made of metal, since it transmits a maximum of the heating energy to the rinsing liquid due to the good heat conduction properties.

The production of the housing cover can also continue to be produced, for example, by injection molding without significant additional expense for the discharge nozzle. The certain existing complexity of the shape of the lid due to the suction is not significantly increased by the additional arrangement of the pressure nozzle.

The heat energy required for heating the rinsing liquid according to the invention provides a heating means which is in contact with the pipe of the heating device from the outside. As the heating means, e.g. Thick film resistors, tubular heaters or heating wires are used, which directly touch the outside of the tube. Since the pipe is free of interruptions, the orientation of the heating means on the pipe is basically freely selectable. The heating means may e.g. in the form of mutually parallel rings, spirally or as flat strips are arranged transversely or parallel to the tube longitudinal axis. The method for applying the heating means to the tube jacket surface, for example by printing the tube with the thick-film resistor material is thereby simpler. As overheating protection, the heating device may have a temperature sensor, for example an NTC or PTC resistor.

The tube may also consist of temperature-resistant plastic, in particular electrically conductive plastic. In this embodiment, the heating means may already be integrated into the pipe, so that the application of heating means can be omitted as a manufacturing step.

According to the invention, the suction nozzle protrudes centrally into the region of the heating device and, with the formation of a radial gap, reaches the front side as far as the impeller. This has, in addition to a compact design, the advantage that the flushing liquid sucked in through the suction nozzle can be selectively guided in a uniform axial flow up to the suction opening of the impeller. During operation of the pump can be done with appropriate heating of the housing parts and thus also of the suction already preheating the sucked through the suction rinse. This effect can be enhanced by additional heating means in or at the suction nozzle.

The flow of the scavenging liquid sucked in from the direction of the lid is deflected by 180 degrees in the impeller and then flows spirally coaxially with the sucked-in rinsing liquid in an annular-cylindrical space on the inside of the heating to the lid back. In order for this flow reversal process to be as energy-efficient as possible, the impeller in an advantageous embodiment of the invention in the direction of the housing cover curved cover plates for deflecting the axially sucked Spülflüssigkeitsströmung in the axially opposite direction to the discharge nozzle on. The cover plates can be hemispherical curved to deflect the centrally centrally or centrally sucked by the impeller rinsing liquid from the suction nozzle between the cover plates of the impeller almost completely on a curved path by 180 degrees. The outer diameter of the suction nozzle facing the cover plate is smaller than that of the opposite cover plate, since so the rinsing liquid can be optimally deflected into the hollow cylindrical space.

Also responsible for the pump action blades of the impeller can promote by their shape and arrangement, the deflection of the flow. In a further advantageous embodiment of the invention, the impeller on radially employed blades. The vanes can be curved over their entire radial length and in the direction of the pressure-side outlet openings of the impeller. The curvature can be more pronounced at the blade ends in order to convey the flow at the exit from the impeller even more effectively the desired flow direction.

In the region of the outlet openings of the impeller, the flow due to the rotation of the impeller has a large radial direction component. According to a further preferred embodiment of the invention can therefore be arranged between the impeller and the discharge nozzle, a guide device for further flow deflection. It may consist of fixed vanes, which are arranged annularly downstream of the outlet opening of the impeller. The vanes may easily extend radially in the annular cylindrical space. Its blade surface may be curved to further counteract the swirl of the flow exiting the impeller. Thus, the flow component is increased in the axial direction.

According to a further advantageous embodiment of the invention, the guide device is arranged on the lid. The guide can be connected as a separate part fixed to the lid or integrally formed on the lid. A one-piece design requires fewer items and thus cheaper the production of the pump housing.

In a further advantageous embodiment of the invention, the housing cover has spiral-shaped guide elements for the flow line of the rinsing liquid from the heating device into the discharge nozzle. The guide elements facilitate the transition of the rinsing liquid from the ring-cylindrical space in the cylindrical discharge nozzle by focusing the flow towards the discharge nozzle. The guide elements are preferably integrally formed in the lid around the suction nozzle in the form of guide spirals. They are to be designed in such a way that the transfer of the rinsing liquid into the discharge nozzle takes place without a significant loss of kinetic energy.

Even in the manufacture of the lid made of plastic, the complexity of the geometries to be produced due to production limits. They are z. B. then reached, if due to undercuts parts after casting would no longer be destructively removed from the mold. In an alternative advantageous embodiment of the invention, the housing cover is therefore at least partially made of an elastomer. This allows the lid to be demoulded non-destructively even with very complex geometries. In addition, due to its rubber-elastic properties, the elastomeric part of the lid has the ability to largely adapt to the rinsing liquid flow during the deflection from the heating device into the pressure nozzle. As a result, it is possible to dispense with special spiral-shaped guide elements for guiding the flow largely.

In order for the lid of the elastomeric material to meet the requirements for stability and dimensional stability with respect to the parts adjacent to it, in particular the impeller, in an advantageous embodiment of the invention, rigid moldings can stiffen the housing cover. You can ensure a defined position especially of the suction against the impeller to exclude collisions. In addition, the tightness of a rigid part of the lid z. B. be guaranteed relative to the heater reliable. Sections of the elastic deck are thereby clamped between the tube of the heater and the rigid moldings.

Figur 1:

eine perspektivische Darstellung einer ersten Ausführungsform der erfindungsgemäßen Pumpe;

Figur 2:

einen axialen Längsschnitt durch die in Figur 1 gezeigte Pumpe;

Figur 3:

den Hydraulikteil der in Figur 2 gezeigte Pumpe;

Figur 4:

eine Vorderansicht des in Figur 2 dargestellten Laufrades;

Figur 5:

eine perspektivische Ansicht des in Figur 2 dargestellten Leitapparats;

Figur 6:

einen axialen Längsschnitt durch eine zweite Ausführungsform der erfindungsgemäßen Pumpe.

The principle of the invention with reference to a drawing by way of example explained in more detail. Show it:

FIG. 1:

a perspective view of a first embodiment of the pump according to the invention;

FIG. 2:

an axial longitudinal section through the in FIG. 1 shown pump;

FIG. 3:

the hydraulic part of in FIG. 2 shown pump;

FIG. 4:

a front view of the in FIG. 2 illustrated impeller;

FIG. 5:

a perspective view of the in FIG. 2 illustrated distributor;

FIG. 6:

an axial longitudinal section through a second embodiment of the pump according to the invention.

In FIG. 1 a first embodiment of a pump according to the invention 10 is shown, which consists of two main assemblies, namely an electric motor 12 and an adjoining hydraulic part 14. The hydraulic part 14 encloses a substantially hollow cylindrical housing cover 16, in concentric with a longitudinal axis 11 of the pump 10, a suction nozzle 18 is arranged. Seen from the outside, a discharge nozzle 20 is integrally formed on the housing cover 16, the wind skew to the axis 11 extends (see. FIG. 2 ). The housing cover 16 has connecting elements 22, with which the pump 10 is mounted within a dishwasher. Outside on the lateral surface of the housing cover 16, a plug contact strip 24 is arranged with seven parallel arranged side by side lugs 26 for the power supply of the pump 10.

In operation, the pump 10 sucks flushing liquid from a washing container of a dishwasher centrally via the suction nozzle 18. Within the housing cover 16, the rinsing liquid is heated before it is pumped back into the rinsing container of the dishwasher via the discharge nozzle 20. The heating of the rinsing liquid takes place by means of a heating device (see. FIG. 2 ), which also draws their energy via the contact lugs 26 of the plug contact strip 24.

The very compact construction of the pump 10, in particular the small outer diameter of the hydraulic part 14, which is not substantially greater than that of the electric motor 12, allows a horizontal installation of the pump 10; its longitudinal axis 11 thus extends substantially horizontally.

FIG. 2 shows an axial longitudinal section through the in FIG. 1 A housing bottom 28 of the hydraulic part 14 connects to the end face of the electric motor 12 and extends to the housing cover 16. At this end face of the discharge nozzle 20 is formed, the longitudinal axis 13 at an acute angle to the longitudinal axis (13) of the discharge nozzle (20, 120) is arranged. Between the housing bottom 28 and the housing cover 16 is a perforation-free metal tube 30 which is connected via a sealing member 32 with the housing cover 16 and a sealing member 34 liquid-tight with the housing bottom 28. On the lateral surface of the metal tube 30 are four-ring encircling and spaced from each other thick-film resistors 36 printed.

In the housing cover 16 of the suction nozzle 18 is centrally located, which adjoins an impeller 40 with one of its end faces to form a radial gap 38. The impeller 40 consists of a facing the suction port 18 cover plate 42 and an opposite, facing the housing bottom 28 cover plate 44. Between the two curved cover plates 42 and 44, the blades 46 of the impeller 40 extend. It is rotatably connected to one end of a shaft 48 of Electric motor 12 which projects through the housing bottom 28 in the hydraulic part 14.

On a flange-like portion 50 of the housing cover 16, a nozzle 52 with staffed vanes 54 is attached approximately at the height of the impeller 40. The housing cover 16 also has spiral-shaped guide elements, a Leitspirale 21 for flow conduction of the washing liquid from the heater 30, 36 in the discharge nozzle 20.

During operation of the pump 10, the impeller 40 sucks through the suction nozzle 18 rinsing liquid from a washing container of a dishwasher and presses them radially outward as a result of the centrifugal force. Due to the curvature of the cover plates 42 and 44, the flushing liquid is thereby deflected in the radial direction along a curved path in the direction of the guide vanes 54 of the distributor 52 by more than 90 degrees parallel to the pump longitudinal axis 11. For better clarification of the flow path of the rinsing liquid by the hydraulic part 14 is this separately in FIG. 3 represented, wherein the respective flow direction is symbolized by arrows.

The rinsing liquid then does not impinge perpendicularly, but at an angle with respect to the longitudinal axis 11 on the inside of the metal tube 30. The vanes 54 of the nozzle 52 then help to redirect the rinse liquid A arriving axially via the suction port 18 in the direction of discharge port 20. The deflected rinsing liquid flow then flows along the inside of the metal tube 30 heated by the thick-film resistors 36 and is thereby brought to a desired temperature. This can be done evenly and with relatively little energy input in a short time due to the length of the tube 30 and the number of thick film resistors 36. The speed with which the flushing liquid flows past the inside of the tube 30 can be influenced by means of the angle of attack of the guide vanes 54 of the guide apparatus 52. For example, these can be adjusted depending on the program by an actuator connected to a control device.

Due to the rotation of the impeller 40, the rinsing liquid flow flows helically in the direction of the pressure nozzle 20. The vanes 54 of the nozzle 52 thereby convert rotational components of movement of the flow in horizontal component of motion, so that the rinsing liquid by a ring-cylindrical space man the inside of the heater 30, 36 sufficiently fast reaches the discharge nozzle. The Leitspirale 21 bundles the flow and gives it a largely laminar characteristic in front of the discharge nozzle 20, through which the rinsing liquid leaves the hydraulic part 14 in direction B again.

FIG. 4 shows a single representation of the impeller 40 in a plan view. It has a cover plate 42 with a smaller and a cover plate 44 with a larger outer diameter. Between the two cover plates 42, 44 five blades 46 are arranged, which are curved in the radial direction. The rinsing liquid enters the impeller 40 centrally via the suction port 18, is pressed radially outwards by the rotor blades 46 between the cover disks 42, 44 due to the centrifugal force, and leaves the rotor wheel 40 again over its outer circumference.

FIG. 5 shows a single view of the nozzle 52 in perspective view. The annular nozzle 52 includes radially outwardly facing, slightly adjusted guide vanes 54 which are integrally formed on a ring 51. The inner diameter D1 of the ring 51 corresponds to the outer diameter of the flange-like portion 50 of the housing cover 16, on which the nozzle 52 is pressed so that it rotatably on the flange-like portion 50 sits.

FIG. 6 shows a further embodiment of a pump 110 according to the invention with an indicated electric motor 112 and a hydraulic part 114. In contrast to the in the FIGS. 1 to 5 In the embodiment shown, the pump 110 has a housing cover 116, which essentially consists of an elastomeric part 117 with rubber-elastic properties. The elastomeric part 117 of the lid 116 replaces mainly the known from the first embodiment Leitspirale.

The elastomeric part 117 is liquid-tight over two annular ribs 115 at a central suction port 118. Via two further ribs 113, the elastomeric part 110 is sealed against a metal tube 130. The metal tube 130 printed with the thick-film resistors 136 is connected on the front side on one side via a sealing element 134 to a housing bottom 128 and on the other side via a sealing element 132 to a dimensionally stable annular cover element 111.

So that the contact pressure required for the tightness acts on the connection points between the elastomeric part 117 and the suction connection 118 or the tube 130, rigid molded parts are provided at these points. At the junction with the suction nozzle 118, a rigid stiffening ring 107 and at the junction with the metal tube 130, a rigid stiffening ring 109 is arranged. In addition, the stiffening ring 107 which is angled in cross-section serves for the dimensional stability of the elastomeric part 117 in the region of the impeller 140. In this way it is also ensured that the elastomeric part 117 does not collide with the cover disk 142 of the impeller 140 during operation of the pump 110. At the same time, this stably held by the stiffening ring 107 in its form portion of the elastomeric member 117 serves to form a radial gap 138 between the cover plate 142 of the impeller 140 and the suction nozzle 118th

Due to the rubber-elastic properties of the elastomeric part 117 of the housing cover 116 may in this embodiment, in contrast to the in the FIGS. 1 to 5 embodiment shown to a diffuser and a Leitspirale be largely dispensed with. The elastomeric part 117 adapts to the rinsing fluid flow in its elastic region and thus ensures an optimal flow transition into the pressure port 120.

LIST OF REFERENCE NUMBERS

10, 110 -

pump

11, 13 -

longitudinal axis

12, 112 -

electric motor

14, 114 -

hydraulic part

16, 116 -

housing cover

18, 118 -

suction

19 -

tubular area

20, 120 -

pressure port

21 -

spiral baffle

22 -

connecting element

24 -

Plug contact strip

26 -

contact tag

28, 128 -

caseback

30, 130 -

metal pipe

32, 34, 132, 134 -

sealing element

36, 136 -

Thick-film resistor

38, 138 -

radial gap

40, 140 -

Wheel

42, 142, 44, 144 -

cover disc

46, 146 -

blade

48 -

wave

50 -

flange-like section

51 -

ring

52 -

diffuser

54 -

vane

107, 109 -

stiffening ring

111 -

annular cover element

113, 115 -

ribs

117 -

elastomeric part of the housing cover 116

A, B -

Flow direction of the rinsing liquid

D1 -

Inner diameter

Claims (12)

1. Pump (10, 110), particularly for dishwashers, with a housing consisting of a housing base (28, 128), a housing cover (16, 116) and a heating device (30, 130, 36, 136), which is arranged therebetween, for heating a rinsing liquid, which forms an annular side wall of the housing, with an impeller (40, 140) arranged in the housing, with a suction stub pipe (18, 118) arranged in the housing cover (16, 116) axially with respect to the axis of rotation of the impeller (40, 140), and with a pressure stub pipe (20, 120), characterised in that the pressure stub pipe (20, 120) is arranged in the housing cover (16, 116), wherein a longitudinal axis (11) of the suction stub pipe (18, 118) is arranged at an acute angle to the longitudinal axis (13) of the pressure stub pipe (20, 120).
2. Pump according to claim 1, characterised in that the heating device (30, 130, 36, 136) comprises a pipe (30, 130) with a closed annular cross-section.
3. Pump according to claim 2, characterised in that the heating device (30, 130, 36, 136) comprises heating means (36, 136) in contact with the pipe (30, 130) at the outer side.
4. Pump according to any one of the preceding claims, characterised in that the suction stub pipe (18, 118) protrudes into the heating device (30, 130, 36, 136) and reaches up to the impeller (40, 140) with formation of a radial gap (38, 138) at the end face.
5. Pump according to any one of the preceding claims, characterised in that the impeller (40, 140) comprises cover discs (42, 142, 44, 144), which are curved in the direction of the housing cover (16, 116), for deflecting the rinsing liquid flow, which is axially sucked from the suction stub pipe (18, 118), in the axially opposite direction onto the pressure stub pipe (20, 120).
6. Pump according to any one of the preceding claims, characterised in that the impeller (40, 140) has radially placed scoops (46, 146).
7. Pump according to any one of the preceding claims, characterised in that a guide device (52) for flow deflection is arranged between the impeller (40) and the pressure stub pipe (20).
8. Pump according to claim 7, characterised in that the guide device (52) is arranged at the housing cover (16).
9. Pump according to any one of the preceding claims, characterised in that the housing cover (16) has spiral guide elements (21) for flow guidance of the rinsing liquid from the heating device (30, 36) to the pressure stub pipe (20).
10. Pump according to any one of the preceding claims, characterised in that the housing cover (116) consists at least partly of an elastomer.
11. Pump according to any one of the preceding claims, characterised by rigid moulded parts (107, 109) for stiffening the housing cover (116).
12. Water-conducting domestic appliance, particularly dishwasher, at least comprising a pump according to any one of the preceding claims.

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