EP1827199B1 - Dishwasher comprising a sorption drying device, and method for the operation thereof - Google Patents

Description

The invention relates to a dishwasher with a Sorptionstrockenvorrichtung. The invention further relates to a method for operating a dishwasher with at least one partial program section "drying", wherein in this part program section of a fan air from a washing container of the dishwasher and / or ambient air is passed through a sorption column with reversibly dehydratable material in the washing and the air moisture is removed during the passage.

Conventional dishwashing machines are known to have a rinsing process whose program sequence generally consists of at least one partial program step "pre-rinsing", one sub-program step "cleaning", at least one sub-program step "intermediate rinsing", one sub-program step "rinsing" and one sub-program step "drying". To increase the cleaning effect while the rinse liquor is heated before or during a Teilprogrammschrittes. The heating of the rinse liquor is usually carried out by means of electric heaters. For drying the items to be washed in a dishwasher different drying systems are known.

So is out of the DE 20 16 831 a dishwashing machine of the type mentioned, in which the air is passed from the washing container via a closable opening in the wall of the washing container on reversibly dehydratable material and from there via an opening to the outside. The desorption of the reversible dehydratable material takes place during the stoppage phase of the device, wherein the resulting water vapor is passed through the opening to the outside. The dishwasher described is disadvantageous from an energetic point of view, since the regeneration of the reversibly dehydratable material takes place during a standstill phase of the device, thus at a time when none of the partial program steps described above is performed. A further disadvantage is that, by discharging the water vapor produced during the regeneration of the reversibly dehydratable material to the outside, damage to the surrounding Kitchen furniture can not be excluded. The regeneration is associated with an additional energy requirement, which is incurred in addition to the energy required during the sub-program steps.

To keep the energy consumption when operating a dishwasher as low as possible, is from the DE 103 53 774.0 the Applicant discloses a dishwasher with a rinsing container and devices for rinsing crockery by means of rinsing, which has a sorptionskolonne containing air-conducting, reversibly dehydratable material containing the rinsing, wherein the sorption on the one hand for drying the dishes and on the other hand for the desorption of the sorption used thermal energy Heating the rinsing liquor and / or the dishes located in the washing container is at least partially used.

To solve the same problem suggests the DE 103 53 775.9 the applicant, for operating a device in the at least one partial program section "drying" air from a washing container and / or from ambient air through a sorption column and into the washing container, wherein the sorbent column contains reversibly dehydratable material and the air withdraws moisture during the passage ,

By using reversibly dehydratable material with hygroscopic property, e.g. Zeolite, a heating of the material to be treated in the preceding part program step "drying" partial program step is normally no longer necessary. As a result, a considerable energy saving is possible.

The DE 100 58 188 A1 uses a drying fan with an adjustable speed for drying dishes.

The mode of operation is based on the fact that the humid air in the rinsing container is blown out of the rinsing container via a ventilation opening during a partial program section "drying" by means of the drying blower. However, any blower activities that concern the program step "cleaning" are not provided here. The drying fan is therefore used solely for the removal of moisture-laden air, u. U. means of admixing fresh air to avoid vapor formation, but not to introduce this air in any kind of additional container or for the return of air in the dishwasher.

The DE 36 26 887 A1 discloses a dishwashing machine with a sorption drying device and with a fan. It is clear after Sp. 5, Z. 29 ff., That the regeneration phase of the sorption "after completion of the drying process" is performed, which leads in each case to a significant program extension with high energy expenditure. According to the further example according to FIG. 2, two containers with adsorptive desiccant have to be provided in order to reduce the overall time in order to reduce the time required. However, this increases the space requirements and design effort quite considerably.

From the EP 0 358 279 B1 a device for drying dishes in a domestic dishwasher is known in which the rinsing liquor is heated by a heater disposed outside the washing, preferably an electric water heater, wherein a largely closed drying system is provided in the air from the washing through a through Heating regenerable drying device and circulated from this back into the washing. In this case, the drying device consists of a dry container in thermal contact with the heater, which is filled with a moisture adsorbing desiccant. The connection of the drying container with the heater already present for heating the rinsing liquor results in an immediate operational readiness of the drying apparatus after the rinsing process has ended. The desiccant is hereby placed at least partly as a jacket around the heating elements of the heater, so that the desiccant can be heated in the drying container during each heating process and thus dried.

The drying container is formed as a double-walled hollow cylinder, in which the dry material is stored. The arrangement of the inlet and outlet ports for connection to the closed air system takes place in a diagonally opposite arrangement. This results in the disadvantage of a relatively high flow resistance, so that provided for promoting the air flow fan must be operated with very high power. This is negative in terms of noise and energy consumption noticeable.

Due to the structural design of the Sorptionstrockenvorrichtung, which causes an inhomogeneous heat input into the dry material, the desorption is time consuming and can also lead to local overheating of the desiccant and thus to its irreversible damage. The desorption is also difficult because the heater is located in the center of the double-walled hollow cylinder and a radial propagation of the heat to the desiccant close to the outer hollow cylinder wall is hardly possible due to the axially flowing air flow.

The object of the present invention is therefore to provide a method for operating a dishwasher and a dishwasher, with which a shortening of the duration of a washing program with several partial program steps is possible.

This object is achieved by the inventive method with the features of claim 1 and by a dishwasher with the features of claim 6. Advantageous developments of the present invention are given in the dependent claims.

In the method according to the invention for operating a dishwasher with at least one partial program step "drying", wherein in this part program step by a fan air from a washing container of the dishwasher and / or ambient air is passed through a sorption column with reversibly dehydratable material in the washing and the air during the Passage moisture is removed, the fan is operated in accordance with a main controller of the dishwasher with different speeds. This results in the possibility of significantly reducing the duration of a partial program step "drying".

In an advantageous embodiment, the passage of air through a continuously operable with a variable speed fan, wherein the speed of the blower is set according to a desired period of the part program step. According to this advantageous embodiment, a dishwasher can be operated during the partial program step with rinsing liquor to be heated with a constant, low and thus noise-optimized speed. On the other hand, it is possible to increase the speed of a controlled blower so that the adsorption process is accelerated, whereby a shortening of the drying time is possible.

Such a time-reduced wash program is accompanied in this case with an increased operating noise. It is therefore advantageous if the speed of the fan in several stages by an operating element of the dishwasher is selectable. In other words, a function may be provided in the operating element of the dishwasher, which allows a user to actively select a "quick-flushing program", wherein the user then deliberately decides for a concomitant increased noise development.

According to an expedient variant of this process according to the invention, the air is heated by condensation heat during the passage of the sorption column and, if necessary, additionally heated by an electric heating element. This achieves that high-temperature air is introduced into the washing compartment of the dishwasher, which increases its moisture absorption capacity, so that the duration of the partial program step "drying" can be reduced.

According to a further expedient embodiment, the ware to be treated is stored in a partial program step which runs before the partial program step "drying", e.g. Rinse thoroughly, heated with rinse water to be heated. As a result, the items to be dried to be dried at the beginning of the part program step "drying" on an already higher heat of intrigue, so that the delivery of the moisture on the items to be washed is further improved to the dry air. This also makes it possible to achieve a reduction of this partial program step.

A dishwasher according to the invention has the same advantages as explained in connection with the above method.

In a dishwasher designed according to the invention, in particular domestic dishwasher, with a rinsing container and devices for rinsing ware by rinsing liquor and with a Sorptionstrockenvorrichtung, this having an air-connected with the rinse container, reversibly dehydratable material containing sorbent column, wherein the sorbent on the one hand for drying the Dishes and on the other hand, the heat energy used for desorption of the sorbent column is used to heat the rinsing tank located in the rinsing and / or Spülguts, a blower of Sorptionstrockenvorrichtung is speed controlled by a main control unit of the dishwasher.

One advantage is that a very simple structural design results for such a dishwasher. The dishwasher can, in principle, as in the DE 103 53 774.0 the applicant described, whose content is included in this application, where appropriate, added. The machine described here is distinguished by the control and operation of the sorption drying device, in particular the blower, which is designed with speed controllable for controlling the drying time.

According to a preferred feature, air from the rinsing tank and / or from the ambient air is passed through the sorption column and into the rinsing tank during a partial program step with rinsing liquor to be heated, preferably during the "drying" partial program step.

According to a further preferred feature, the rinsing container has an outlet with a line to the sorption column, wherein the line preferably has a shut-off valve and then in the flow direction preferably via an inlet valve to the ambient air and the rinse tank has an inlet with a line from the sorption column, wherein the line to the sorption column, the fan is arranged which at least temporarily introduces at least a portion of the air in the washing or from the ambient air of the sorption column. In a preferably closed air system, an exchange of polluted air from the environment is completely excluded, whereby a Rückanschmutzung the treated items is prevented. The blower is easy to control, so that the use of the sorption column and thus the drying process can be precisely controlled.

Conveniently, a preferably electric heating element is arranged for desorption of the reversibly dehydratable material and the heating of the air conducted into the washing compartment. This is preferably arranged in the reversibly dehydratable material or in the line to the sorption column.

It is also expedient if the blower of the sorption drying device can be selected steplessly or in several stages by an operating element of the dishwasher.

The invention will be explained in more detail with reference to the embodiment of a method in a dishwasher shown in the drawing.

The inventive method for operating a dishwasher with at least one partial program step with rinsing liquor to be heated to a nominal temperature and / or at least one partial program step "drying" is carried out in the illustrated embodiment in a dishwasher, which schematically, as in DE 103 53 774 and / or the 103 53 775 the applicant described, is constructed. A dishwasher is known to have dishwashing processes whose program sequence generally consists of at least one partial program step "prewash" V, one partial program step "cleaning" R, at least one partial program step "intermediate flushing" Z, one partial program step "final rinse" K and one partial program step "drying" T. Preferably, the drying in the embodiment, as in DE 103 53 774 and / or the DE 103 53 775 described, executed. In the figure, the typical temperature profile of the rinsing liquor is shown during these partial program steps, wherein the figure represents both the operation in a conventional dishwasher and an operation according to the inventive method.

The partial program steps "pre-wash" V and "intermediate rinse" Z are of minor importance for the inventive methods, so that they are described in the following description will not be considered in detail. With the beginning of the partial program step "cleaning" R, the rinsing liquor is usually heated to a nominal temperature T _nenn to achieve the desired cleaning effect. In an energy-optimized dishwasher with a sorption drying device, as is already known in the prior art, the desorption, ie the heating of the reversibly dehydratable material also takes place during the partial program step "cleaning" R instead.

For heating the rinsing liquor, a conventional heating, e.g. a water heater, to be used. It is also conceivable to dispense with such a "water heater" and to use only the necessary energy for desorption.

For this purpose, an (air) heater arranged in the sorption drying device is operated which comprises the reversibly dehydratable material, e.g. Zeolite, heated to a high temperature. During desorption of the reversibly dehydratable material, air is removed from a rinse tank, e.g. with an outlet, passed through a sorption column and then back into the rinse tank via an inlet, wherein the air is heated while passing through the heater. In this case, the air is sucked out of the washing container by means of a blower and forced through the sorption column. The hot water vapor emerging from the sorption column and the now heated air enter the rinsing tank through the inlet already mentioned above and there they encounter the circulated treatment or rinsing liquor and / or the dishes which are heated.

Usually, the sorption drying device is operated only to the point until the reversibly dehydratable material is completely desorbed, ie dehumidified (section A in the figure). In the embodiment shown in the figure, this state would be reached at a time t _a , at which the rinsing liquor and / or the material to be treated has reached a temperature T _Des . This temperature is typically below to be achieved nominal temperature T _nom. To bridge this temperature difference, the electric heating element and the blower of the sorption drying device continue to operate and hot air in the Driven rinse container until the circulated rinsing liquor and / or the material to be treated reaches the desired nominal temperature (Section B). This state is achieved with appropriate dimensioning of the sorption drying device, in particular the power of the heater, the speed of the fan and the arrangement and the geometry of the sorption column at a time t _b .

In order to be able to carry out the subprogram step "cleaning" R more quickly, ie in order to achieve the desired nominal temperature _Tennenn faster, according to another variant, an additional heating can be provided, which the rinsing liquor during the section A and / or during the section to increase the temperature of T _{Des is operated} on T _nenn , so that the nominal temperature T _nenn already reached at a time t _c (Section C). The additional heating can optionally be designed as a water heater, for example as a water heater, or as inserted into the air circulation air heater. In both cases, the additional heating can be dimensioned such that only a lower heating power needs to be made available, which is able to bridge the missing temperature difference between T _des and T _nenn . Not apparent from the figure, but readily recognizable to a person skilled in the art, is the fact that regardless of the time of reaching the nominal temperature _Tnenn (in the embodiment t _b or t _c ), the heating phase of the rinsing liquor is terminated and then a drop in the treatment temperature until the end of the program step "cleaning" R is the result. How strong the treatment temperature drop and the duration of the waste is depends on the type of cleaning program performed and on the insulating properties of the dishwasher.

According to a further variant, the speed of the fan of the sorption during the part program step can also be provided to increase "cleaning" R, in order to achieve a further reduction in the time taken to reach the nominal temperature T _nom. This could be made preselectable for a user of the dishwasher, for example via an operating element.

The drying of the items to be washed is carried out in conventional dishwashers by the so-called self-heat drying in the partial program steps "rinsing" and "drying" (Section 1). The rinsing liquor is in the Partial program step "rinsing" heated, whereby the hot rinsed wash ware dries by the built-up self-heat of the dishes during the drying process by itself. In order to achieve this self-heat drying, the rinsing liquor is therefore heated to the temperature T _{K in} the partial program step "rinsing" and applied to the items to be washed by means of spraying. Due to the relatively high temperature of the wash liquor in the partial program step "rinse" usually 65 ° C to 75 ° C is achieved that a sufficiently large amount of heat is transferred to the items to be washed, so that the water adhering to the items evaporated by the heat stored in the items to be washed ,

A substantial energy saving is effected by Sorptionstrockenvorrichtungen, since in these a heating of the wash liquor in the partial program step "rinse" K is basically not necessary (Section 2), but can be made to a small extent (Section 3). Drying is achieved by passing air from the rinsing tank and / or from ambient air through the sorption column into the rinsing tank in the "drying" sub-program step, wherein the sorption column containing reversibly dehydratable material extracts moisture from the air during the passage. Through the use of reversibly dehydratable material with hygroscopic property, such as zeolite, heating of the material to be treated in the subprogram "drying" preceding Teilprogrammschritt is usually not necessary (Section 2), but can be heated to low temperatures, for example up to 30 ° C, while "rinsing" continue to be made (Section 3). By heating the air by means of the sorption column, in which the heat of condensation of the water vapor is released, the moisture absorption capacity is increased with each passing through the sorption column, which leads to the improvement of the drying result and to shorten the drying time. An additional heating of the air with a supplementary heating in the sub-program step "drying" on the heating with the sorbent addition and thus eg the dishes in dishwashers is usually not required because the released in the sorption heat energy is sufficient, the air at high temperatures, eg 70 ° C, warm up. The sorption column itself is heated by the heat of condensation to temperatures of up to 160 ° C, for example.

An acceleration of the drying process, which takes place in conventional dishwashers via a time program control and continues until the time t ₁ , can be realized by providing a continuously or in several stages speed-controlled fan in the Sorptionstrockenvorrichtung. By increasing the speed of the adsorption process is accelerated, resulting in a shortening of the drying time.

If an increase in the temperature during the partial program step "rinsing" is dispensed with, the drying can already be ended at time t ₂ (section 2). A further shortening of the drying time results from the above-mentioned heating of the rinse-off temperature (Section 3), whereby the drying at time t ₃ can be terminated. It can be assumed that the drying efficiency or the degree of drying of the items to be dried is identical in all three variants.

Since the increase in the rotational speed of the blower of the sorption drying device is accompanied by an increased noise radiation, it is advantageous to have this mode of operation actively carried out by a user of the dishwasher. This could be done, for example, by the provision of a corresponding operating element which is connected to a main controller of the dishwasher and enables a corresponding mode of operation.

With the present invention, a method is provided with which it is possible to economically operate a dishwasher of the aforementioned type and to keep the associated energy expenditure time-optimized low.

Claims (13)

1. Method for operating a dishwasher having at least one program sub-segment "Drying" (T), wherein in this program sub-segment (T) air from a wash container of the dishwasher and/or ambient air is directed by a fan through a sorption column containing reversibly dehydratable material into the wash container and moisture is extracted from the air as it passes through, and having a program sub-step "Cleaning" (R), wherein in this program sub-step (R) air from the wash container of the dishwasher and/or ambient air is directed by the fan through the sorption column containing reversibly dehydratable material into the wash container for the desorption of the sorption column, characterised in that different speeds are provided for the fan, with the fan being operated at at least one of the different speeds according to a main controller of the dishwasher in the program sub-segment "Drying" (T) and in the program sub-step "Cleaning" (R).
2. Method according to claim 1, characterised in that the air is conducted through by a fan that can be operated steplessly at a variable speed, the speed of the fan being set according to a desired duration of the program sub-step "Drying" (T).
3. Method according to claim 1 or 2, characterised in that the speed can be preselected by a user of the dishwasher.
4. Method according to one of the preceding claims, characterised in that as the air passes through the sorption column it is heated by condensation heat and if necessary additionally by an electric heating element.
5. Method according to one of the preceding claims, characterised in that the items for washing that are to be treated are heated with wash liquor in a program sub-step "Final rinse" (K) running prior to the program sub-step "Drying" (T).
6. Dishwasher having a wash container and devices for washing items for washing using wash liquor and having a sorption drying device, this latter having a sorption column that contains a reversibly dehydratable material and is connected in an air-conducting manner to the wash container, the sorption column being used to dry dishes in at least one program sub-segment "Drying" (T) on the one hand and the thermal energy used for the desorption of the sorption column being used in at least one program sub-step "Cleaning" (R) to heat the wash liquor present in the wash container and/or the items for washing on the other hand, characterised in that a fan of the sorption drying device is configured so that its speed can be controlled by a main control unit of the dishwasher, with different speeds being provided for the fan and the fan being operated at at least one of the different speeds according to a main controller of the dishwasher in the program sub-segment "Drying" (T) and in the program sub-step "Cleaning" (R).
7. Dishwasher according to claim 6, characterised in that air from the wash container and/or ambient air can be conducted through the sorption column and into the wash container during a program sub-step with wash liquor to be heated, preferably during the program sub-step "Drying".
8. Dishwasher according to claim 6 or 7, characterised in that the wash container has an outlet with a line to the sorption column, the line preferably having a shut-off valve and adjacent to it in the flow direction preferably an inlet valve for the ambient air and the wash container having an inlet with a line from the sorption column, the fan being disposed in the line to the sorption column and being able to be used at least occasionally to introduce at least some of the air in the wash container or from the ambient air to the sorption column.
9. Dishwasher according to one of claims 6 to 8, characterised in that a preferably electric heating element is provided for the desorption of the reversibly dehydratable material and the heating of the air conducted into the wash chamber.
10. Dishwasher according to claim 9, characterised in that the heating element is disposed in the reversibly dehydratable material or in the line to the sorption column.
11. Dishwasher according to claim 10, characterised in that the speed of the fan can be selected steplessly or in a plurality of steps by an operating element of the dishwasher.
12. Dishwasher according to one of claims 6 to 11, characterised in that the thermal energy used for desorption can be stored in a heat storage unit, e.g. a latent storage unit, prior to being used to heat the wash liquor and/or the items for washing.
13. Dishwasher according to one of claims 6 to 12, characterised in that a method according to one of claims 1 to 5 can be executed.

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