EP3369357A1 - Water-conducting domestic appliance and method for operating a water-conducting domestic appliance - Google Patents

Abstract

The invention relates to a water-conducting domestic appliance (1), in particular a dishwasher, having a washing compartment (2) for receiving items to be washed, a first container (20) and a second container (30) for receiving water, wherein between the first container (20). and the rinsing container (2), a thermal insulation means (21) is arranged, the second container (30) in a thermal contact (31) with the washing compartment (2) is arranged, and means (40) for transferring the water from the first container (20) is provided in the second container (30) for drying the dishes.

Description

The present invention relates to a water-conducting household appliance and a method for operating a water-conducting household appliance.

Conventional dishwashers have a container designed as a heat exchanger, which is mounted, for example, on one side of the dishwasher. The container can be filled with water from the connected water line. The DE 10 2013 002 116 A1 describes a dishwasher with an inlet water storage. The inlet water storage is filled, for example, after a rinse with cold fresh water. The water can warm up to the ambient temperature until the next rinse. This preheated compared to the fresh water water can be used for the next rinse, which requires less energy to heat the water.

Such a container can also be used to cool an inside of the washing container after completion of the rinsing process and thereby bring about condensation of the humidity in the washing container on this inside due to the temperature difference. In this way, the air in the washing container is deprived of moisture, so that the items to be washed in the washing can dry faster. This type of drying is particularly energy-efficient.

However, in some countries, such as the US, it is envisaged that dishwashers will be connected to a hot water line. The water often has a temperature of about 60 ° C. Thus, the water is similar warm as the items to be washed or the air in the washing after a flushing process is completed. Therefore, the method described can not be applied in these countries.

Against this background, an object of the present invention is to provide an improved water-conducting household appliance.

According to a first aspect, a water-conducting household appliance, in particular a dishwasher, with a washing container for receiving items to be washed, a first container and a second container for receiving water is proposed. Between the first container and the rinsing container, a thermal insulation means is arranged, the second container is arranged in thermal contact with the rinsing container, and a means for transferring the water from the first container into the second container for drying the dishes is provided.

This water-bearing household appliance makes it advantageous to have cold water in stock, even if the household appliance with water only has a hot water connection.

By filling the first container with water, the water temperature can adapt to the ambient temperature. The first container is in thermal contact with the environment. For example, the first container is at least partially made of a metal which has a good thermal conductivity. After a certain cooling period, which depends on how large the temperature difference between the environment and the first container, as well as how efficiently the heat exchange with the environment takes place, the first container and the water in this then approximately at the ambient temperature, for example, about 20 ° C - 25 ° C.

By the thermal insulation means, which is formed for example as a polymer foam and heat does not conduct or only very bad, the first container is thermally insulated from the washing compartment. This ensures that the water in the first container does not heat up when flushing with hot water, which may be up to 90 ° C, is performed.

In contrast, the second container has thermal contact with the washing container. Thermal contact means in particular that at least a portion of the washing container has approximately the same temperature as the second container. For example, the second container is made at least in a portion of a heat-conducting metal, wherein the rinsing container is also made in at least a portion of thermally conductive metal, and wherein these two metal Sections are in thermal contact. Then heat can be transferred from one to the other.

An efficiency of this heat conduction depends in particular on the specific heat conduction coefficients of the materials forming the thermal contact and on a size of the contact surface. The specific thermal conductivity coefficient is given, for example, in watts per meter and Kelvin. The thermal contact can be characterized for example by a transferable power per unit time and temperature difference. For example, metals have a specific heat transfer coefficient of over 40 W / mK. Very good heat conductors are copper and silver with a specific heat transfer coefficient of over 400 W / mK.

If, after completion of a rinse, the cooled to ambient temperature water from the first container is filled in the second container, for example by means of a pump, so that a cooling of the part of the washing container, which is in thermal contact with the second container, achieved. Preferably, the part of the washing container which is cooled in this case is a side wall of the washing container. Then water can condense on the inside of this side wall from the warm and moist air in the washing. As a result, the air in the washing container is deprived of moisture, so that they can absorb moisture again. This promotes the evaporation of rinsing water remaining on the items to be washed and thus accelerates the drying of the items to be washed.

The water-conducting domestic appliance is, for example, a dishwasher, in particular a domestic dishwasher.

According to one embodiment of the water-conducting domestic appliance, the means for transferring the water from the first container into the second container is designed as a valve, a pump and / or a suction lift pump.

Advantageously, the first container may be arranged so that the gravity is sufficient to fill the water in the second container. Then it is sufficient to arrange a line with a corresponding valve between the first container and the second container and open the valve to fill the water.

Furthermore, it is possible to use existing pumps, such as a circulating pump of the water-conducting household appliance, for refilling. Then no additional pump is needed.

According to a further embodiment of the water-conducting household appliance, the second container is arranged with a side wall of the washing containers in a surface contact.

Under a surface contact in the present case is understood in particular that the contact surface, through which heat is transferable, for example, at least 10 cm ² comprises. The surface contact may also be indicated with respect to a surface of the sidewall, for example, the surface contact should be at least 10% of that surface.

This embodiment has the advantage that a surface temperature of the inwardly facing surface of the sidewall corresponds to the temperature of the water in the second container. This is understood to mean, in particular, that the temperature of the water in the second container and the temperature of the inner side do not have a large temperature difference. For example, a temperature difference is at most 5 ° C, at most 10 ° C or at most 20 ° C. When determining this temperature difference, a certain compensation time must be taken into account, which depends in particular on the thermal contact. For example, it may take five minutes for the temperatures to equalize or even ten minutes.

The surface contact can be achieved by a number of smaller contact points. For example, it can be provided that 20 support points, each with a square centimeter of contact surface, are distributed over the side surface. If these support points, for example, from a very good heat conducting material, such as copper, are made, so a good thermal contact is ensured.

According to a further embodiment of the water-conducting domestic appliance, the first container and / or the second container are at least partially made of a material with a specific heat transfer coefficient of at least 40 W / mk, preferably at least 80 W / mK, more preferably at least 150 W / mK formed.

According to a further embodiment of the water-conducting domestic appliance, the first container and / or the second container have an inner structure for enlarging an inner surface.

For example, inwardly directed cooling fins are provided. This advantageously makes it possible to use the entire heat capacity of the water for cooling even without active mixing of the water in the second container.

Water is a poor conductor of heat with a specific coefficient of thermal conductivity of about 0.5 W / mK, which is why this measure can improve the effectiveness of the cooling effect.

According to a further embodiment of the water-conducting domestic appliance, the first container and the second container have an equal volume.

In the present case, an equal volume is understood to mean an identical volume or a substantially identical volume with up to 20% deviation.

According to a further embodiment of the water-conducting household appliance, the first container and the second container each have a volume in the range of 2.5 to 3.0 liters.

This amount of water provides sufficient heat capacity to facilitate efficient drying of the dishes.

According to a further embodiment of the water-conducting domestic appliance, the thermal insulation means is designed as an air layer, a vacuum chamber, a fleece and / or a polymer layer.

According to a further embodiment of the water-conducting domestic appliance, the thermal insulation means has a coating for reflecting thermal radiation.

Such a coating may for example be formed as a mirror with a reflective layer of aluminum or of silver.

According to a further embodiment of the water-conducting household appliance, the first container has a means for exchanging heat with the environment.

Such means can be formed, for example, by a side wall of the container made of a good heat-conducting material, such as metal. The more efficient the heat exchange with the environment, the faster the water in the first container cools and the sooner a drying process with cooled water can be accelerated.

According to a further embodiment of the water-conducting domestic appliance, the means for exchanging heat with the environment is designed as a heat sink.

Such a heat sink offers a particularly efficient heat exchange with the environment. Depending on how the water-bearing household appliance is set up, further measures make sense. In a built-in dishwasher, for example, a louver or a rear ventilation can be provided, which allows a certain exchange of air with the room air. Further, a fan may be provided to assist actively circulating the air to achieve faster cooling.

According to a further embodiment of the water-conducting domestic appliance, the thermal contact of the second container with the rinsing container is designed as a heat-conducting means.

The heat-conducting agent has, in particular, a particularly high specific coefficient of thermal conductivity. The heat-conducting agent may also have a more complex structure. For example, a so-called heat pipe can be provided, which forms the thermal contact. This allows different requirements to be met by the installation situation, which are not possible, for example, under the proviso of a surface contact.

For example, the second container is arranged under the washing, because there is still unobstructed space. To cool the side surface of the washing container, a heat pipe transfers the heat of the side wall to the second container and cools the side wall therewith.

According to a further embodiment of the water-conducting household appliance, a fan is provided for circulating the air in the washing container.

Such a fan is designed, for example, as a fan. The blower helps to dry the items to be washed, as dry air, which is produced on the cool side wall of the washing container, makes it easier for it to come into contact with the still-wet items to be washed. After absorbing moisture, it can also be returned to the side panel more quickly.

According to a further embodiment of the water-conducting household appliance, the water-conducting household appliance has only a single hot water connection.

According to a second aspect, a method for operating a water-conducting household appliance, in particular a dishwasher, is proposed. The water-conducting household appliance has a washing container for receiving items to be washed, a first container and a second container for receiving water. Between the first container and the washing container, a thermal insulation means is arranged and the second container is arranged in thermal contact with the washing compartment. Furthermore, a means for transferring the water from the first container into the second container is provided. In a first step, the first container is filled with warm water. In a second step, the water in the first vessel is cooled to ambient temperature. In a third step, a rinsing process is performed. In a fourth step, the cooled to ambient temperature water from the first container is filled in the second container to dry the dishes.

This method advantageously makes it possible to use this type of drying support even if the dishwasher is operated with warm water or has only a hot water connection.

According to one embodiment of the method, the first container is refilled with warm or hot water once the cool water has been filled into the second container.

For example, directly after a flushing operation, when the cold water has been filled from the first tank into the second tank, the first tank is refilled with warm water from the hot water pipe. The warm water begins to cool immediately in the first container. Thus, a period of time between two rinsing operations with final drying of the items to be washed can be kept small.

According to a further embodiment of the method, the water from the first container is filled into the second container only when a predetermined maximum temperature of the water in the first container is not exceeded.

Furthermore, a computer program product is proposed, which causes the execution of the method as explained above on a program-controlled device.

A computer program product, such as a computer program means may, for example, be used as a storage medium, e.g. Memory card, USB stick, CD-ROM, DVD, or even in the form of a downloadable file provided by a server in a network or delivered. This can be done, for example, in a wireless communication network by transmitting a corresponding file with the computer program product or the computer program means.

The embodiments and features described for the proposed domestic appliance apply correspondingly to the proposed method.

Further possible implementations of the invention also include not explicitly mentioned combinations of features or embodiments described above or below with regard to the exemplary embodiments. The skilled person will also add individual aspects as improvements or additions to the respective basic form of the invention.

• Fig. 1 zeigt eine schematische perspektivische Ansicht einer Ausführungsform einer Haushalts-Geschirrspülmaschine;
• Fig. 2 zeigt einen schematischen Schnitt eines Ausführungsbeispiels eines wasserführenden Haushaltsgeräts;
• Fig. 3 zeigt ein beispielhaftes Diagramm eines Temperaturverlaufs von Wasser in dem ersten Behälter; und
• Fig. 4 zeigt ein Blockschaltbild eines beispielhaften Verfahrens zum Betreiben eines wasserführenden Haushaltsgeräts.

Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the embodiments of the invention described below. Furthermore, the invention will be explained in more detail by means of preferred embodiments with reference to the attached figures.

• Fig. 1 shows a schematic perspective view of an embodiment of a household dishwasher;
• Fig. 2 shows a schematic section of an embodiment of a water-conducting household appliance;
• Fig. 3 shows an exemplary diagram of a temperature profile of water in the first container; and
• Fig. 4 shows a block diagram of an exemplary method for operating a water-conducting household appliance.

In the figures, the same or functionally identical elements have been given the same reference numerals, unless stated otherwise.

The Fig. 1 shows a schematic perspective view of an embodiment of a household dishwasher 1 as an example of a water-conducting household appliance. The household dishwasher 1 comprises a washing container 2, which is closed by a door 3, in particular watertight. For this purpose, a sealing device can be provided between the door and the washing container 2. The washing container 2 is preferably cuboid. The washing container 2 may be arranged in a housing of the household dishwasher 1. The rinsing container 2 and the door 3 can form a rinsing chamber 4 for rinsing dishes.

The door 3 is in the Fig. 1 shown in their open position. By pivoting about a provided at a lower end of the door 3 pivot axis 5, the door 3 can be closed or opened. With the help of the door 3, a charging opening 6 of the washing container 2 can be closed or opened. The rinsing container 2 has a bottom 7, a floor 7 opposite the ceiling 8, one of the closed Door 3 arranged opposite the rear wall 9 and two oppositely disposed side walls 10, 11. The bottom 7, the ceiling 8, the rear wall 9 and the side walls 10, 11 may for example be made of a stainless steel sheet. Alternatively, for example, the bottom 7 may be made of a plastic material.

On the side wall 11, a first container 20 and a second container 30 are arranged. Between the first container 20 and the side wall 11 is also a thermal insulation layer 21 is arranged, which is presently formed as a 1 cm thick polyurethane layer. The second container 30, however, is arranged in a thermal contact 31 with the side wall 11. For this purpose, the second container 30 on a metal portion which is in surface contact with the side wall 11. Further, the first container 20 is connected to the second container 30 via a line with intermediate pump 40. Via this line and by means of the pump 40, water can be transferred from the first container 20 into the second container 30. The pump 40 is thus an example of a means for transferring. If, at the end of a rinsing process, cold water from the first container 20 is filled into the second container 30, this water cools the inner side of the side wall 11 via the thermal contact 31. Moisture from the warm and moist air in the washing container 2 then condenses on the cool inner side. This allows the air to absorb moisture again, which accelerates a drying process of the washware.

The household dishwasher 1 further comprises at least one Spülgutaufnahme 12 to 14. Preferably, several, for example three, Spülgutaufnahmen 12 to 14 may be provided, wherein the Spülgutaufnahme 12 a lower Spülgutaufnahme or a lower basket, the Spülgutaufnahme 13 an upper Spülgutaufnahme or upper basket and the Spülgutaufnahme 14 may be a cutlery drawer. As the Fig. 1 Furthermore, the Spülgutaufnahmen 12 to 14 are arranged one above the other in the washing container 2. Each Spülgutaufnahme 12 to 14 is either in the Spülbehälter 2 in or herausverlagerbar out of this. In particular, each Spülgutaufnahme 12 to 14 hineinschiebbar in an insertion direction E in the washing container 2 and opposite to the insertion direction E in an extension direction A from the washing container 2 can be pulled out.

The Fig. 2 shows a schematic section of an embodiment of a water-conducting household appliance 1, wherein in the Fig. 2 only the essential details are shown. The water-conducting household appliance 1 has a washing container 2, which in the present case is made of stainless steel sheet. On the right side wall 11 of the washing container 2, a first container 20 is arranged, wherein between the side wall 11 and the first container 20, a thermal insulating layer 21, which is presently designed as a vacuum insulation panel, is arranged. The first container 20 is also made of stainless steel sheet and has a volume of 3 l. On the outwardly facing side of the first container 20, a means for heat exchange 22 is arranged, which is presently designed as a heat sink made of aluminum. By this measure, a heat transfer to the environment is significantly accelerated and hot or hot water in the first container 20 can cool faster.

On the left side wall 10 of the washing container 2, a second container 30 is arranged, which is also made of stainless steel sheet and has a volume of 3 I. Between the second container 30 and the side wall 10, a thermal contact 31 is formed. This is presently formed by a thin aluminum plate as a surface contact. It can be provided to improve the thermal contact 31 by applying a thermal paste, for example with a share of silver. The thermal compound compensates for slight unevenness between the contacting surfaces. Further, the stainless steel sheets of the washing container 2 and the second container 30 are formed thinner in the region of the thermal contact 31 than the other parts, since stainless steel has a comparatively poor specific coefficient of thermal conductivity. On the inside of the second container 30, which faces the thermal contact 31, an inner structure 50 in the form of aluminum fins is arranged in this exemplary embodiment, which improves heat transfer to the water in the second container 30.

The first container 20 and the second container 30 are connected to each other via a line with intermediate pump 40. The pump 40 is configured to pump water from the first container 20 into the second container 30. If, at the end of a rinsing process, cooled water from the first container 20 is filled into the second container 30, this water cools the inner side of the side wall 10 via the thermal contact 31. Moisture from the warm condenses on the cool inside and humid air in the washing container 2. This allows the air to absorb moisture again, whereby a drying process of the dishes is accelerated.

Fig. 3 shows an exemplary diagram of a temperature profile of water in the first container 20 (see Fig. 1 . 2 ), which was filled at time t0 at a temperature of 60 ° C. By heat exchange with the environment, which here 20 ° C, the water slowly cools down. The cooling process at high temperature difference is initially fast and then loses speed. At time t1, the water is approximately at the ambient temperature of 20 ° C.

Fig. 4 shows a block diagram of an exemplary method for operating a water-conducting household appliance 1, for example, the household dishwasher of Fig. 1 , In the first step S1, the first container 20 (see Fig. 1 or Fig. 2 ) filled with warm or hot water. The warm water cools in the second step S2 to ambient temperature (see, eg Fig. 3 ). In the third step S3, a flushing process is started. Since the first container 20 is thermally insulated from the washing container 2 by an insulating layer 21, the water therein remains cold. When the rinsing process has arrived in the drying step, in the fourth step S4 the cold water is pumped from the first container 20 via the pump 40 into the second container 30, which is in a thermal contact 31 with a side wall 10, 11 of the rinsing container 2. The cold water absorbs heat, whereby the inside of the side wall 10, 11 cools, whereby moisture condenses from the warm and moist air on the inside. The condensed moisture then drains off, for example. The air can then absorb moisture from the still wet dishes, whereby the drying of the dishes is accelerated.

Although the present invention has been described with reference to embodiments, it is variously modifiable. For example, in particular in the first container, a temperature sensor may be provided which determines the water temperature. Based on this it can be decided whether the drying process, as proposed, is efficiently accelerated. Furthermore, circulating pumps may also be provided in the first container and / or the second container in order to prevent mixing of the water and thus formation of thermal barrier layers in the water.

Used reference signs:

1

water-conducting household appliance

2

rinse tank

3

door

4

inner space

5

swivel axis

6

loading port

7

ground

8th

cover

9

rear wall

10

Side wall

11

Side wall

12

Spülgutaufnahme

13

Spülgutaufnahme

14

Spülgutaufnahme

20

first container

21

insulation layer

22

Means for exchanging heat

30

second container

31

thermal contact

40

Means for decanting

50

internal structure

A

pull-out

e

insertion direction

S1

step

S2

step

S3

step

S4

step

t

timeline

T

temperature axis

t0

time

t1

time

Claims (15)

Water-conducting domestic appliance (1), in particular a dishwasher, with a washing container (2) for receiving items to be washed, a first container (20) and a second container (30) for receiving water, wherein between the first container (20) and the washing container (20) 2) a thermal insulation means (21) is arranged, the second container (30) in a thermal contact (31) with the washing compartment (2) is arranged, and means (40) for transferring the water from the first container (20) in the second container (30) is provided for drying the items to be washed. A household water appliance according to claim 1, wherein the means (40) for transferring the water from the first tank (20) to the second tank (30) is formed as a valve, a pump and / or a siphon pump. Water-conducting household appliance according to claim 1 or 2, wherein the second container (30) with a side wall (10, 11) of the washing containers (2) is arranged in a surface contact. Water-conducting household appliance according to one of claims 1-3, wherein the first container (20) and / or the second container (30) at least partially made of a material having a specific coefficient of thermal conductivity of at least 40 W / mk, preferably at least 80 W / mK on preferably at least 150 W / mK are formed. A water-conducting household appliance according to any one of claims 1-4, wherein the first container (20) and / or the second container (30) have an inner structure (50) for enlarging an inner surface. A household water appliance according to any one of claims 1-5, wherein the first container (20) and the second container (30) have an equal volume. A household water appliance according to any one of claims 1-6, wherein the first container (20) and the second container (30) have a volume in the range of 2.5 - 3.0 liters. Water-conducting domestic appliance according to one of claims 1-7, wherein the thermal insulation means (21) as an air layer, a vacuum chamber, a non-woven and / or a polymer layer is formed. Water-conducting household appliance according to one of claims 1-8, wherein the thermal insulation means (21) has a coating for reflecting heat radiation. A water-conducting household appliance according to any one of claims 1-9, wherein the first container (20) comprises means for exchanging heat (22) with the environment. Water-conducting household appliance according to claim 10, wherein the means for exchanging heat (22) with the environment as a heat sink is formed. Water-conducting household appliance according to one of claims 1 - 11, wherein the thermal contact (31) of the second container (30) with the washing container (2) is designed as a heat-conducting means. Water-conducting household appliance according to one of claims 1 - 12, wherein a fan (50) for circulating the air in the washing compartment (2) is provided. Water-conducting household appliance according to one of claims 1 - 13, wherein the water-conducting domestic appliance (1) has only a single hot water connection. Method for operating a water-conducting domestic appliance (1), in particular a dishwasher, having a washing compartment (2) for receiving items to be washed, a first container (20) and a second container (30) for receiving water, wherein between the first container (20) and the rinsing container (2), a thermal insulation means (21) is arranged, the second container (30) in a thermal contact (31) with the washing compartment (2) is arranged, and means (40) for transferring the water from the first container (20) is provided in the second container (30), with: Filling (S1) the first container (20) with warm water, Cooling (S2) the water in the first container (20) to ambient temperature, Performing (S3) a purge, and Transfer (S4) of the cooled to ambient temperature water from the first container (20) in the second container (30) for drying the dishes.

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