EP1667569B1 - Dishwasher - Google Patents

Description

The invention relates to a dishwasher with a washing container and devices for washing dishes.

As is known, a dishwasher has a washing method whose program sequence generally consists of at least one sub-program step “pre-wash”, a sub-program step “cleaning”, at least one sub-program step “intermediate washing”, a sub-program step “rinsing” and a sub-program step “drying”. To increase the cleaning effect, the rinsing liquid is heated before or during a partial program step. The rinsing liquid is usually heated by means of electrical heaters. Different drying systems are known for drying items to be washed in a dishwasher.

For example, the items to be washed can be dried by self-heat drying if the washing liquid is heated in the “final rinse” sub-program step and thus the hot-rinsed items dries automatically due to the inherent heat generated by the items during the “drying” sub-program step. In order to achieve this self-heating drying, the rinsing liquid in the partial program step "final rinsing", e.g. in a heat exchanger, heated to a certain temperature and applied to the items to be washed via spray devices available in the dishwasher. The relatively high temperature of the washing liquid in the "final rinse" subprogram step of usually 65 ° C to 75 ° C ensures that a sufficiently large amount of heat is transferred to the items to be washed so that the water adhering to the items to be washed evaporates due to the heat stored in the items.

In another known drying device, a separate heat source, for example a hot air blower, is used in the washing compartment to heat the moist air mixture during the drying process so that the air in the washing compartment can absorb a larger amount of moisture.

Dishwashers are known in which the moist air is vented to the outside. This is disadvantageous because the surrounding kitchen furniture is damaged.

Therefore, further dishwashers are known in which the moist air is passed over condensation surfaces on which the moisture condenses before being discharged. This condensed water is either directed into the rinsing container or into special collecting containers.

From the DE 20 16 831 A1 a dishwasher of the type mentioned is known in which the air from the washing compartment is passed through a closable opening in the wall of the washing compartment onto reversibly dehydratable material and from there to the outside via an opening. The desorption of the reversibly dehydratable material takes place during the standstill phase of the device, whereby the water vapor that is produced in the process is directed to the outside again via the opening. As already explained above, this is disadvantageous because the surrounding kitchen furniture is damaged.

A disadvantage of the heating systems described above according to the prior art described above is that the heating of the rinsing liquid is associated with a high energy requirement and the required thermal energy must be generated anew for each heating phase by means of the electrical heating elements. The known heating systems also have the disadvantage that the heating of the rinsing liquid in the sub-program step "rinsing" and the processes in the sub-program step "drying" themselves are associated with a high energy requirement and the required thermal energy is lost after the drying process.

In the dishwasher of the EP 0 358 279 A1 rinsing liquor is heated by a water heater arranged outside its rinsing container and pressed into a distribution and spray system by a pump. A largely closed drying system is used for a drying process, in which air circulates from the washing compartment via a drying device which can be regenerated by heating and from this circulates back into the washing compartment. The drying device consists of a drying container which is in thermal contact with the heater and which is filled with a drying agent that adsorbs moisture, such as a zeolite. The air flow of the drying system is with provided a closure that interrupts the air circulation during the washing of the dishwasher.
The US 6,434,857 B1 relates only to a washer-dryer whose tumbler is separated from the circuit of a drying system by a valve during a washing cycle. The object of the present invention is therefore to provide a dishwasher with which it is possible, from an economic point of view, to efficiently clean and dry the items to be washed in the washing compartment and to keep the associated energy consumption as low as possible.
This object is achieved by the dishwasher according to the invention having the features according to claim 1. Advantageous further developments of the present invention are characterized in the subclaims.

The dishwasher according to the invention with a washing container and devices for washing dishes using washing liquor has a sorption column that is connected to the washing container in an air-conducting manner and contains reversibly dehydratable material, the sorption column on the one hand for drying the dishes and on the other hand for desorption of the sorption column to heat the heat energy used in the Rinsing container located washing liquor and the dishes is at least partially usable.
By using reversibly dehydratable material with hygroscopic properties, e.g. B. zeolite, heating of the items to be treated is preferably not necessary in the part program step "rinsing". A heating of the items to be treated in the partial program step which precedes the partial program step “drying”, in particular the partial program step “final rinsing”, is possible, but not useful. Nevertheless, a slight warming during "rinsing", z. B. to 30 ° C, be appropriate. This means a substantial energy saving. The generally always occurring warming of the air due to the released heat of condensation in the sorption column in the part program step "drying" increases its moisture absorption capacity each time it is passed through the sorption column, which improves the drying result and shortens the drying time Drying time leads. An additional heating of the air with a heater in the partial program step "drying" and thus also of the dishes is normally not necessary because the sorption column due to the heat of condensation of the steam to high temperatures, z. B. 150 ° C, heated, and thereby the air sufficiently high temperatures, z. B. 60 ° -70 ° C reached.
As is known, the reversibly dehydratable material is heated to very high temperatures for desorption, for which purpose thermal energy is necessary. The stored liquid emerges as hot water vapor. According to the invention, the water vapor is preferably passed into the treatment room of the device with an air stream and the air in the treatment room is thus heated and thereby the washing liquor and / or the dishes are also heated. The air that is passed through cools down, causing the water vapor to partially condense at the top. This is preferably done as a closed air circuit. The introduction of the hot water vapor and the heated air into the treatment room during a partial program step with the treatment liquid to be heated or, under certain circumstances, with the treatment liquid that has already been heated is largely sufficient to heat the treatment liquid sufficiently. This means that further heating can largely be dispensed with and the thermal energy used for desorption can be used almost entirely to heat the treatment liquid, rinsing solution and / or dishes, apart from the low energy required to overcome the binding forces between water and reversibly dehydratable material . In addition to saving energy, efficient cleaning of the items to be treated is also guaranteed.
The present invention provides a dishwasher with which it is possible, from an economic point of view, to efficiently clean and dry the items to be washed and to keep the associated energy consumption as low as possible.
According to a preferred feature of the invention, air from the washing container and / or from the ambient air on the one hand during the partial program step "drying" and on the other hand preferably during a partial program step with rinsing liquid to be heated, preferably during the partial program step "cleaning" and / or "pre-rinsing" the sorption column and passed into the rinsing tank, bringing the above mentioned advantages are used as intended in the dishwasher according to the invention.

According to the invention, the rinsing container has an outlet with a line to the sorption column, the line preferably having a shut-off valve and then, in the flow direction, preferably an inlet valve to the ambient air, and the rinsing container also has an inlet with a line from the sorption column, wherein in a fan is arranged in the line to the sorption column which at least temporarily introduces at least part of the air in the washing container or from the ambient air of the sorption column. In the case of a preferably closed air system, an exchange of contaminated air from the environment is completely excluded, which prevents back contamination of the treated goods. The fan can be easily controlled so that the use of the sorption column can be precisely controlled. In addition, the fan increases the effect of the sorption column, since the air to be passed through is conveyed more quickly.

In a further embodiment, the sorption column has a container for the reversibly dehydratable material, which allows the exchange of moisture and / or heat between the reversibly dehydratable material and the air surrounding it.

According to the invention, a heating element, preferably an electrical heating element, is arranged for desorption of the reversibly dehydratable material.

According to the invention, the heating element is arranged in the line to the sorption column for desorption of the reversibly dehydratable material (11).
In another, advantageous embodiment, the air that can be introduced into the washing container via the inlet can be cooled so that the dishes are not damaged by high temperatures.

According to an additional variant, a droplet separator is arranged at the outlet or the line at the outlet is led up a partial area so that no spray water reaches the sorption column via the line.

According to another embodiment, the thermal energy used for desorption is prior to use for heating the washing liquor and / or the dishes in a heat store, e.g. B. latent storage, storable.

The invention is explained below with reference to the exemplary embodiment of a dishwasher according to the invention shown in the drawing.

The single FIGURE shows, in a schematic representation, a dishwasher 1 according to the invention with a washing container 2, in which crockery baskets 3, 4 are arranged for the arrangement of items to be washed (not shown).

According to the invention, the dishwasher 1 has a sorption column 10 containing reversibly dehydratable material 11 connected to the washing container 2 in a liquid-conducting manner, the sorption column 10, as will be explained in more detail below, being used on the one hand for drying and on the other hand for heating air that is passed through.

The rinsing container 2 has an outlet 5 with a line 6 to the sorption column 10, arranged in its upper region in the exemplary embodiment described, and an inlet 8 with a line 7 from the sorption column 10, arranged in its lower region in the exemplary embodiment described. In the line 6 to the sorption column 10, a fan 9 is arranged which supplies the sorption column 10 with air from the washing container 2.

With the closed air system, an exchange of contaminated air from the environment is completely excluded, which prevents back contamination of the treated goods.

For desorption of the reversibly dehydratable material 11, an electrical heating element 12 in the embodiment shown is arranged in the sorption column 10 in the embodiment described. This arrangement of the heating element 12 in the sorption column 10 is not part of the invention.

As is known, a dishwasher has a washing method whose program sequence generally consists of at least one sub-program step “pre-wash”, a sub-program step “cleaning”, at least one sub-program step “intermediate washing”, a sub-program step “rinsing” and a sub-program step “drying”. According to the invention and in the exemplary embodiment explained, air is passed from the washing container 2, on the one hand, through the sorption column 10 and back into the washing container 2 during the “drying” part of the program. For this purpose, the fan 9 is switched on. The airway is indicated by the arrows A, B and C. The air introduced into the sorption column 10 by the fan 9 via the line 6 is withdrawn from the reversibly dehydratable material 11 of all moisture. The air is heated by the heat of condensation of moisture or water vapor released in the sorption column, which advantageously increases the air's moisture absorption capacity. The now warmed, z. B. up to 40 ° -70 ° C, and very dry air now passes through line 8 back into the rinsing container. The heated air introduced into the washing compartment 2 is completely dry and, due to the higher temperatures, has a high absorption capacity for moisture. It rises in the washing compartment 2 and absorbs the residual moisture on the items to be washed. As already described above, it is now fed back to the sorption column 10.

As a result of the use of reversibly dehydratable material 11 in the “drying” sub-program step, it is normally not necessary to heat the items to be treated in the “rinsing” sub-program step. This means a substantial energy saving. The heating of the air increases the moisture absorption capacity of the air each time it is passed through the sorption column 10, which leads to an improvement in the drying result and a reduction in the drying time. According to the invention and in the illustrated embodiment, on the other hand, air from the washing container 2 is passed through during a partial program step with washing liquid to be heated or possibly already heated, preferably during the partial program step "cleaning" and / or "pre-rinse", in the described embodiment during the partial program step "cleaning" the sorption column 10 and passed back into the washing tank 2. For this purpose, as already explained above, the fan 9 is switched on. The airway is indicated by arrows A, B and C indicated. The heater 12 is also switched on in order to carry out the desorption of the reversibly dehydratable material 11.

As is known, reversibly dehydratable material 11 is heated to very high temperatures for desorption. The stored liquid emerges as hot water vapor. By directing air by means of the fan 9 through the lines 6, 8 in accordance with the air path of the arrows A, B, C, the water vapor is passed into the washing compartment 2 and the air in the washing compartment is also heated. The introduction of the hot steam and the heated air into the washing compartment 2 during the “cleaning” part of the program in the treatment room is largely sufficient to sufficiently heat the washing solution and / or the dishes. This means that further heating is largely unnecessary and the energy used for desorption can be used almost entirely to heat the washing liquor and / or the dishes, apart from the low energy required to overcome the binding forces between water and reversibly dehydratable material. In addition to saving energy, efficient cleaning of the items to be washed is also guaranteed.

In a further embodiment not shown, a shut-off valve is in the line 6 and then in the flow direction of the airway according to arrow A an inlet valve, for. B. arranged via another line to the ambient air. In the example described above, the shut-off valve is open and the inlet valve is closed, so that only air from the washing compartment 2 is sucked in by the fan 9. By fully or partially closing the outlet valve and fully or partially opening the inlet valve, ambient air is wholly or partially sucked in by the fan 9 and introduced into the washing container via the line 8 and the inlet 7. For this purpose, the rinsing container needs an outlet (not shown) in order to be able to release this air from the environment back into the environment.

In another embodiment, not shown, the outlet 5 is designed in such a way that, due to an increase in the average from the outlet 5 to the line 6, the flow velocity in the line 6 is lower than in the outlet 5, so that there are no water droplets in the air (mist) in the line 6 occur. In order to prevent the penetration of spray water into the line 6 and thus into the sorption column 10, can either the line 6 can be led upwards after the outlet 5 or a droplet separator (not shown) can be arranged at the outlet 5.

In a further embodiment of the invention, not shown, the electrical heating element is not located in the sorption column 10, but in the line 6 between the fan 9 and the sorption column 10, in order to ensure uniform heating of the dehydratable material 11, e.g. B. zeolite to achieve. Excessive temperatures of the dehydratable material can thus advantageously be avoided in order to exclude damage to the dehydratable material 11 resulting therefrom.

The sorption column is - as already described - preferably during a partial program step with the treatment liquid to be heated with a heater to a very high temperature, e.g. B. 300 ° C, so that the sorption column releases the absorbed water. Also in the part program step "drying" the sorption column is heated to high temperatures, e.g. B. 150 ° -200 ° C, due to the heat of condensation of the water vapor or the moisture.
This means that the dry air or the air with steam that is placed in the washing compartment can reach temperatures, e.g. B. 80 ° C, which can damage the dishes, z. B. plastic parts, can lead. The air inlet temperature in the washing area must therefore be reduced in a further embodiment with cooling to such an extent that no damage occurs.

In the partial program step "Drying", residual water is directed to and around the inlet opening, thereby cooling the air flow. In addition, the dry and warm air absorbs part of the water, which leads to the cooling of the air flow due to the evaporation cold. In a partial program step with the treatment liquid to be heated, a heat exchange takes place through the spray water and the air flow with water vapor at the inlet opening. The inlet opening is advantageously designed in such a way that the air flow does not hit the dishes directly and the air flow is adequately cooled by the spray water.
In addition to the heater for heating the sorption column for desorption - hereinafter referred to as air heating - a variant of a dishwasher according to the invention has a flow heater for the washing liquor, if based on the present Invention is not performed on this. If, in a further embodiment of the invention, heating is necessary in the part program step “final rinsing”, this can be achieved either with the flow heater or with the air heater with the fan switched on. The advantage of heating with air heating is that the thermal energy stored in the sorption column can be used for drying in the subsequent partial program step "drying".

In a further variant, the fan can be switched on during the heating phase of the “final rinse” part of the program, with the air heating switched off. As a result, moist air is passed through the sorption column, which absorbs the moisture, and the sorption column and thus also the air that is passed through is heated by the condensation energy released. This means that the heat of condensation can be used to heat the washing liquor and / or the dishes. The sorption column, e.g. B. with zeolite, is in this embodiment with a corresponding large amount of z. B. to design zeolite that a good drying result can also be achieved in the part program step "drying".

The present invention provides a dishwasher with which it is possible, from an economic point of view, to efficiently clean and dry the items to be washed in the washing compartment 2 and to keep the associated energy consumption as low as possible.

Claims (8)

1. Dishwasher (1) with a washing container (2) and devices for rinsing dishes using washing liquor, wherein the dishwasher (1) has a sorption column (10) containing reversibly dehydratable material (11) connected in an air-conducting manner to the washing container (2), wherein the sorption column (10) can be used at least partially on the one hand in order to dry the dishes and on the other hand for the thermal energy used to desorb the sorption column (10) in order to heat the washing liquor located in the washing container (2) and the dishes, wherein the washing container (2) has an outlet (5) with a line (6) to the sorption column (10), wherein the washing container (2) has an inlet (8) with a line (7) from the sorption column (10), wherein a fan (9) is arranged in the line (6) to the sorption column (10), said fan at least temporarily introducing at least one part of the air in the washing container (2) or from the ambient air of the sorption column (10), characterised in that in order to desorb the reversibly dehydratable material (11), a heating element (12) in the line (6) to the sorption column (10) is arranged between the fan (9) and the sorption column (10).
2. Dishwasher according to claim 1,
   characterised in that
   air from the washing container (2) and/or from the ambient air is conducted on the one hand during the sub program step "drying" and on the other hand preferably during a sub program step with washing liquid to be heated, preferably during the sub program step "cleaning" and/or "pre-rinsing", through the sorption column (10) and into the washing container (2).
3. Dishwasher according to claim 1 or 2,
   characterised in that
   the line (6) to the sorption column (10) has a shut-off valve and then in the flow direction an inlet valve to the ambient air.
4. Dishwasher according to one of claims 1 to 3,
   characterised in that
   the sorption column (10) has a container for the reversibly dehydratable material (11), which enables the exchange of moisture and/or heat between the reversibly dehydratable material (11) and the air surrounding it.
5. Dishwasher according to one of claims 1 to 4,
   characterised in that
   an electrical heating element (11) is arranged in order to desorb the reversibly dehydratable material (11).
6. Dishwasher according to one of the preceding claims,
   characterised in that
   the air which can be introduced into the washing container (2) via the inlet (8) can be cooled.
7. Dishwasher according to one of the preceding claims, characterised in that a demister unit is arranged at the outlet (5) or the line (6) at the outlet (5) is guided one subregion upward so that no splash water reaches the sorption column (10) via the line (6).
8. Dishwasher according to claim 1,
   characterised in that
   before being used to heat the wash liquor and/or the dishes the thermal energy used for desorption can be stored in a heat storage tank, e.g. a latent storage unit.

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