DISHWASHING MACHINE HAVING AT LEAST ONE DRYING DEVICE

Description

The present invention relates to a dishwasher having at least one drying device according to the preamble of claim 1.

It is desirable to be able to remove items to be washed which have been processed in a washing compartment of a dishwasher, such as dishes, glasses, cutlery and like, which have been correctly dried at the end of the washing cycle and without water or limescale stains. Thus dishwashers which have various drying devices are known, in order to be able to dry as effectively as possible the items to be washed which have been processed in the washing compartment and before the removal thereof. However, a significant energy input is generally required for the drying, which is undesirable and with the reorganization of energy labels is also increasingly becoming an argument which hinders sales.

The problem underlying the invention is to provide dishwashers with a drying of the items to be washed which is as energy-efficient as possible.

The invention solves this problem by a dishwasher having a drying device which has the features of claim 1. With regard to advantageous embodiments and developments of the invention, reference is made to claims 2 to 8.

Since according to the invention at least one storage device is provided for storing hot water which can be heated by means of water obtained from the washing compartment in the course of processing items to be washed, or is filled with this water, an energy storage device is provided without an energy input in addition to that required for the wash cycle of a dishwashing program to be carried out, said energy storage device being able to be used for preheating replenishing air during a drying phase of the dishwashing program terminating the wash cycle or during another drying phase subsequently following the end of the dishwashing program, such as for example a so-called storage phase (“storage function”). Since additionally at least one heat exchanger is provided, air sucked out of the washing compartment being able to be used therein for preheating replenishing air flowing into the washing compartment, a further possibility is created for preheating the air coming from the environment without an additional energy input being required. Since a single- or multi-track guide channel which is in thermal contact with heat-emitting parts situated in an appliance plinth is additionally provided for the replenishing air, a further energy-neutral possibility is provided for preheating the replenishing air. At the same time, since at least one air conveying device is provided, warm and moist air being able to be sucked thereby out of the washing compartment in a drying phase, it is possible to convey this warm and moist air through the heat exchanger so that during the course of drying this heat exchanger can be refilled with warm air and the high thermal energy associated therewith, which can be used in the heat exchanger for preheating the air. When carrying out a dishwashing program, all of these thermal energy stores are produced in any case in the dishwasher during the course of its washing process which precedes the drying phase, and which comprises one or more sub-washing phases with washing liquid or washing liquor to be heated up, and thus do not require any energy supply from outside so that the energy efficiency is particularly high.

In particular, the replenishing air can be sucked in by means of the negative pressure generated by the air conveying device, so that to this end a control or dedicated air conveyance is not required and it is always the case that only sufficient air is drawn in as has been previously conveyed out.

At least one air outlet opening can discharge, for example to the front face of the dishwasher, the still moist and warm air which is sucked out of the washing compartment during the drying phase, in particular outwardly on the front face into the environment, so that possible condensation is prevented within an item of kitchen furniture.

Furthermore, the air outlet opening is thermally decoupled from at least one, in particular external, air inlet opening, for example by a spacing of several tens of centimeters. The spacing can be present, for example, in the transverse direction. For example, the one or more external air inlet openings can be formed, in particular, by one or more through-holes or other openings in the outer walls of the appliance plinth.

Particularly advantageously, the replenishing air flowing into the dishwasher interior of the washing compartment can be freely sucked in by a dedicated air conveying member. Thus overall only a single air conveying member is provided for sucking air out of the washing compartment. The replenishing fresh air flowing into the dishwasher interior of the washing compartment can be sucked in solely by the negative pressure achieved by sucking air out of the dishwasher interior of the washing compartment, and thus is also optimized in terms of construction.

Advantageously, at least one air inlet opening which is accessible from outside in the region of the plinth and an adjoining air duct in the appliance with thermal contact with heated structural units are provided for sucking in the replenishing air. Thus the replenishing air can come into thermal contact with the hot structural units in the plinth and be subjected to a dedicated preheating and also bring about a cooling of these structural units.

If during the drying phase, for storing hot water, the storage device is filled with hot water obtained from the washing compartment in the course of the previous processing of the items to be washed (i.e. process water) and the replenishing air flowing into the washing compartment comes into thermal contact with this storage device filled with the hot process water on its path to at least one air inlet opening of the washing compartment, the construction is very simple and space-saving. A heat exchanger is thus unnecessary between the fresh water which would have to run into the storage device and a water flow coming from the washing compartment.

Advantageously, the at least one aforementioned heat exchanger can operate between the air, i.e. the exhaust air, from the washing compartment and the replenishing fresh air flowing therein, i.e. feed air, in a counterflow principle between these two airflows and thus act in a space-saving and effective manner. In particular, this exhaust air/feed air counterflow heat exchanger ensures that the moist-warm dishwasher interior air, which is sucked out of the dishwasher interior of the washing compartment by means of the air conveying device during the respective drying process, is at least partially dehumidified. The dishwasher interior air, which is blown out of the dishwasher by means of the air conveying device into the environment, can thus be made sufficiently dry by means of the exhaust air/feed air counterflow heat exchanger. In other words, the moisture content of the dishwasher interior air flowing out into the environment is reduced after passing through the exhaust air/feed air counterflow heat exchanger, in particular such that a condensation of water on surfaces outside the dishwasher, such as for example on the floor in front of the dishwasher, is substantially avoided.

Moreover, advantageously the sequence of heating the replenishing air by the storage device for storing hot water originating from the washing compartment in the course of processing, and by the heat exchanger and by the thermal contact with heat-emitting parts situated in the appliance plinth, is variable. Thus the arrangement of the aforementioned thermal functional units in the dishwasher is also variable, so that the respective structural features and spatial relationships thereof can be effectively taken into consideration.

Particularly advantageously, a plurality of the aforementioned thermal functional units can be effective for preheating replenishing air one after the other (in series) and/or adjacent to one another (in parallel).

Overall, the waste heat which is produced in any case by the washing process, which precedes the drying process, of a dishwashing program to be carried out, is used in order to heat up the replenishing ambient air or fresh air flowing into the dishwasher as much as possible and over the entire drying process.

Within the scope of the invention, the drying process is, in particular, a drying phase of the dishwashing program terminating the wash cycle and/or another drying phase subsequently following the end of the dishwashing program, such as for example a so-called storage phase (“storage function”) during which the items to be washed are intended to be kept dry over a lengthy storage period in the washing compartment, such as for example 96 hours when the door of the dishwasher is closed.

Further advantages and features are found in the exemplary embodiments of the subject matter of the invention shown in the drawing and described hereinafter.

In the drawing:

FIG. 1 shows a schematic perspective view obliquely from the front of an embodiment of a dishwasher with a plinth or base carrier for receiving different functional elements in the lower region and with an air inlet opening in the lower region,

FIG. 2 shows the temperature curve over time (x-axis) of the air which has entered through the air inlet opening after the heating thereof in comparison with sucked-in air without heating (illustrated parallel to the x-axis as a constant),

FIG. 3 shows a schematic flow diagram of the air supply of ambient air and the preheating thereof on its guide path before entering the washing compartment of the dishwasher and the conveyance and the emission of heat of warm dishwasher interior air to the environment during a drying process,

FIG. 4 shows different possibilities of the sequence of the heating functional units for the replenishing air, in each case in series,

FIG. 5 shows a parallel circuit of the heating functional units for the replenishing air.

The household appliance shown schematically in FIG. 1 is in this case a dishwasher 1 and namely a household dishwasher. In principle, other household appliances can be considered for a configuration according to the invention.

The household dishwasher 1 described hereinafter according to FIG. 1 has a washing compartment 2 for receiving items to be washed and to be processed such as dishes, pans, cutlery, glasses, cooking utensils, amongst other things, as a constituent part of an appliance body 5 which is partially open or closed toward the outside. The items to be washed can be kept, for example, in baskets 11 and/or a cutlery drawer 10 and so-called washing liquor can be applied thereto. Washing liquor is understood to mean fresh water or, in particular, water circulating during operation with or without detergent and/or rinse aid and/or drying agent. The washing liquor can also contain to a greater or lesser extent contaminants from the ongoing operation. In particular, water freshly supplied to the washing compartment has passed through a water softening system, such as for example an ion exchanger, for the softening thereof. The washing compartment 2 can have an at least substantially rectangular outline with a front face V facing a user in the operating position. This front face V can form part of a kitchen front consisting of adjacent items of kitchen furniture, or in a freestanding appliance can have no relation to other items of furniture.

The washing compartment 2, in particular, can be closed on this front face V by a door or flap 3. In FIG. 1 this door 3 is shown in the partially open position and is thus positioned obliquely to the vertical. In its closed position, however, the door is upright and, according to the drawing, for the opening thereof can be pivoted open about a lower horizontal axis to the front and downwardly in the direction of the arrow 4 so that it is located at least virtually horizontally in the fully open position.

The door 3 can be provided with a decorative panel 6 on the vertical outer and front face V of the dishwasher 1 facing the user in the closed position, in order to provide in this manner a visual and/or haptic enhancement and/or adaptation to the surrounding items of kitchen furniture.

The dishwasher is configured here as a freestanding, or so-called partially integrated or fully integrated, appliance. In the last-mentioned case, the appliance body 5 can also substantially terminate with the outer walls of the washing compartment 2. A housing surrounding this washing compartment on the outside can thus be unnecessary. A plinth or a base carrier 12 for receiving, in particular, functional elements, such as for example a pump for circulating the washing liquor, can be located in the lower region of the dishwasher. The washing compartment 2 is arranged above this appliance plinth 12.

In the exemplary embodiment according to the drawing, a control panel 8 which extends in the transverse direction Q of the dishwasher and which can comprise as a door handle 7a an access opening 7 which is accessible from the front face V for manually opening and/or closing the door 3 is assigned to the movable door 3 in its upper region. By way of example, this access opening is closed at the front and top in the manner of a shell and permits access from below. In the transverse direction Q the dishwasher frequently has an extent of 45, 50 or 60 centimeters. In the depth direction T from the front face V to the rear, the extent is frequently also approximately 60 centimeters. The values are not mandatory. Moreover, the dishwasher 1 does not have to stand directly on a floor B but can be installed inside an item of kitchen furniture approximately at eye level. Then the lower edge of the dishwasher 1 is preferably located ca. 70 to 110 centimeters above the floor in the installed position.

When the door or flap 3 is closed, the washing compartment 2 is defined over the periphery by a total of three fixed vertical walls 13 and two horizontal walls 13, one thereof forming a ceiling (top) and another thereof a floor (bottom) of the washing compartment 2. In the transverse direction Q to the left, a left upright side wall 13 and, to the right, a right upright side wall 13 which extend at least approximately over the vertical height H of the dishwasher 1 adjoin the front face V which faces the user.

The wall 13 forming the floor of the washing compartment 2 and defining this washing compartment substantially downwardly is located approximately horizontally above the plinth 12, i.e. parallel to an external floor B on which the dishwasher 1 can stand. A higher installation, for example approximately at the height of a worktop, is also possible as mentioned above.

As is also visible in FIG. 1, preferably an air outlet opening 16 and an air inlet opening 17 with a spacing therefrom- and thus thermally decoupled therefrom—are located in the region of the plinth 12 facing the front face V, in this case in a plinth panel 15. Additionally or independently thereof, one or more air inlet openings can be provided in one or more other outer defining walls of the appliance plinth. The air outlet opening 16 and the air inlet opening 17 can have in each case an extent of a few centimeters and can be approximately round, elliptical or angled. The spacing between the air outlet opening 16 and the air inlet opening 17 is configured in this case in the transverse direction Q and typically is approximately 30 to 50 centimeters. The air outlet opening 16 and the air inlet opening 17 can be located in a visually attractive manner at the same height. In particular, the air outlet opening 16 can be shaped in the manner of a nozzle and thus ensure an accelerated air throughput which conveys the air far away in front of the dishwasher 1 and thus prevents undesired condensation of the water produced, directly on the plinth panel 15.

According to the invention, it is a main functional principle to use the waste heat produced in the washing process during the following drying process as effectively as possible and to heat up the replenishing ambient air 22 flowing into the dishwasher as much as possible over the entire drying process.

In order to make this possible, at least one air conveying device 18 is provided, warm and moist air 23 being able to be sucked thereby out of the washing compartment 2 in a drying phase. Thus a slight negative pressure is produced in the washing compartment 2 during the operation of the air conveying device 18—such as for example a blower or fan-air 22 being conveyed automatically thereby from the environment into the washing compartment via at least one air inlet opening, without necessarily requiring a dedicated conveying, in particular blowing, fan 19. In FIG. 3, this is illustrated in dashed lines as an option, however.

Additionally at least one storage device 20, which is also denoted in the drawing as the “hot water storage tank”, is provided for storing hot water. The storage device 20 can either be filled with hot water from the washing compartment or the storage device 20 can be heated in the course of processing items to be washed by water obtained from the washing compartment 2, for example via a heat exchanger.

Moreover, at least one heat exchanger 21 is provided, air (exhaust air) sucked out of the washing compartment being able to be used therein indirectly or directly for preheating replenishing air (feed air) flowing into the washing compartment, so that the replenishing air 22 from the environment is also heated. As can be seen in FIG. 3, the storage device 20 is additionally arranged upstream of the heat exchanger 21 for additional preheating of the replenishing ambient air 22. Alternatively, a pure air-air heat exchanger can also be used as the heat exchanger, in which the air (exhaust air) 23 which is sucked out of the washing compartment during the drying phase directly preheats the replenishing air (feed air) 22 from the washing compartment 2. The air 23 is advantageously sucked out through an opening which is preferably located in the upper half of the washing compartment 2, so that liquid is not sucked out therewith.

A single- or multi-track guide channel which is in thermal contact with heat-emitting parts situated in an appliance plinth 12—denoted as a whole by 24—is additionally provided for the replenishing air 22 and thus also ensures that the replenishing air 22 is heated.

All of these measures lead to an effective use of the thermal energy which is contained in any case in the washing compartment as a result of the previous washing process. However, it can be expedient to provide an (additional) heater 25 which is illustrated in FIG. 3 in dashed lines as an option for the replenishing air 22 and/or for heating water in order to optimize or to accelerate the drying process thereby. This heater can be operated, however, much more economically than might be possible without the invention.

As already mentioned above, the replenishing air 22 can be sucked in by means of the negative pressure generated by the air conveying device 18 so that the replenishing air 22 can be freely sucked in by a dedicated air conveying member and overall only one air conveying member (namely 18) is required for sucking air 23 out of the washing compartment 2. This is advantageous in terms of energy and also minimizes the number of components.

At least one air inlet opening 17 which is accessible from outside in the region of the plinth 12 is provided in order to permit the suction of the replenishing air in a targeted and energy-optimized manner. In the appliance, i.e. in the dishwasher 1, an air duct adjoins this air inlet opening, which makes it possible to conduct the replenishing air 22, which is in thermal contact with structural units to be heated in the dishwasher 1, before the entry thereof into the washing compartment 2. This air duct can be configured at least in some regions as an open or closed channel and conduct the replenishing air 22, in particular, past a heated pump and the aforementioned storage device 20 and the heat exchanger 21, and in thermal contact therewith, so that the air 22 can be heated on these parts. The suction is automatically initiated, for example, as soon as the air conveying device 18 conveys air out of the washing compartment 2 which generally is preferably the case during the entire drying phase.

During the drying phase, for storing hot water, the storage device 20 can be filled with hot water obtained from the washing compartment in the course of processing the items to be washed, so that heat produced earlier in the wash cycle (namely in the rinse-aid cycle) continues to be used, instead of the hot water obtained therein simply being pumped away. As already described above, the storage device can be filled directly with water from the washing compartment 2 or can be preheated with fresh water which can be preheated by waste heat from the washing compartment via a heat storage device.

The at least one heat exchanger 21 can operate in a counterflow principle between the warm air 23 sucked out of the washing compartment 2 and the replenishing air 22 flowing into the washing compartment 2 so that it forms an air-air heat exchanger and a heat transfer with a high level of efficiency. It is plotted in FIG. 2 how great the difference is between the fresh air temperature 22 without the invention and with the invention in the drying phase. Thus without additional external energy use, the temperature of the sucked-in air 22 rises from ca. 24° C. to ca. 33° C. at the start of the drying phase. The sucked-in air 22 is thus dry and warm at the at least one intake opening thereof into the washing compartment 2 and thus very suitable for drying dishes, whereas a large part of the moisture is transported away from the items to be washed with the conveyed-out process air 23. The heat exchanger 21 can also operate indirectly with the hot water from the storage device 20, wherein the heat exchanger 21 and the storage device 20 can also be combined in one structural unit (combination tank).

As is clear in FIG. 4, for example, the sequence of heating the replenishing air 22 by the storage device 20 for storing hot water originating from the washing compartment 2 in the course of processing, and by the heat exchanger 21 and by the thermal contact 24 with heat-emitting parts situated in the appliance plinth 12, is variable and thus also the arrangement of the aforementioned thermal functional units in the dishwasher 1. In FIG. 4 all of the theoretical sequential arrangements of the aforementioned structural units are illustrated. When entering the plinth region 12 the air 22 generally will come first into contact with hot parts such as a pump, bitumen, weights and/or softening system, such as for example an ion exchanger, but this is not mandatory.

The aforementioned structural units are shown in FIG. 4 one after the other—in series—whereas in the view according to FIG. 5 it is clear that a plurality of the aforementioned thermal functional units can be effective for preheating replenishing air 22 not only one after the other but additionally or alternatively adjacent to one another—in parallel.

In addition to the drying device according to the invention which uses a heat recovery system of the heat which is present or produced in any case in the appliance 1, additionally further drying devices can be provided, for example by opening the door or via zeolite drying.

The potential of the dishwasher in terms of thermal energy, together with the combination of the various heat sources (20; 21; 24) is very effectively utilized by the invention.

LIST OF REFERENCE SIGNS

• • 1 Household appliance,
  • 2 Washing compartment,
  • 3 Door,
  • 4 Pivoting direction,
  • 5 Appliance body,
  • 6 Decorative panel,
  • 7 Access opening,
  • 8 Control panel,
  • 10 Cutlery drawer,
  • 11 Basket,
  • 12 Plinth,
  • 13 Walls of washing compartment,
  • 14
  • 15 Forward-facing plinth panel,
  • 16 Air outlet opening,
  • 17 Air inlet opening,
  • 18 Air conveying device,
  • 19 Conveying fan,
  • 20 Storage device,
  • 21 Heat exchanger,
  • 22 Air from the environment,
  • 23 Air from the washing compartment,
  • 24 Heat-emitting parts,
  • V Front face,
  • Q Transverse direction,
  • B Floor,
  • H Vertical height