EP1830688B1 - Water-conducting household appliance and method for the operation thereof - Google Patents

Description

The invention relates to a dishwasher, with at least one substantially closed water circulation, in which rinsing liquid is circulated in accordance with a program control unit, wherein the rinsing liquid is conveyed during the circulation for filtering impurities through a filter element.

When operating a dishwasher, depending on the degree of soiling of the items to be cleaned, larger and smaller impurities are removed from the items to be washed by the rinsing liquid. In order to prevent rinsing fluid already being circulated during a rinsing program section from being applied again to the items to be washed, so-called dishwashing machines arrange more or less complex filter arrangements in the region of the rinsing pan or the sump. A filter arrangement mounted in the sump of the dishwasher frequently consists of a coarse sieve which filters out large-diameter contaminants from the rinsing liquid, a fine sieve whose mesh diameter is in the range from 0.9 to 1.1 mm, and a micro sieve connected downstream of the fine sieve Mesh size is about 0.3 mm to filter even small impurities from the rinsing liquid. The purpose of such a filter arrangement is, during the circulation of the rinsing liquid, to filter out the largest possible proportion of impurities from the rinsing liquid. When pumping out the rinsing liquid, e.g. When changing from one rinsing program section to the next rinsing program section, the largest possible part of the impurities should be conveyed out of the washing compartment of the dishwasher in order to avoid clogging of the filter arrangement.

A disadvantage of the arrangement just described is that in practice only a portion of the impurities held in the filter assembly can be removed from the dishwasher during pumping. Therefore, it is necessary that at least some of the filter elements of the filter assembly are temporarily removed manually by a user of the dishwasher and cleaned manually. Around To spare the user of a dishwasher such unpleasant activity, it would be desirable if the filter assembly of the self-cleaning type would be.

A dishwasher with such a self-cleaning filter is for example from the US 3,179,116 known. The filter consists of a helical spring, wherein the distances of superimposed spiral sections are variably adjustable. When the rinsing liquid is circulated from the rinsing trough to the rinsing arms, the spring has a small length and thus small spiral section distances, so that contaminants detached from the ware are filtered by the spiral spring. When pumping the flushing liquid, which is caused by a change in the direction of rotation of the pump, the length of the coil spring is increased, whereby the distance between two adjacent spring sections increases, so that the adhering to the coil spring impurities flushed by the pumped flushing liquid into the interior of the coil spring and finally fed to the water drain. The changing of the length of the coil spring is made by water pressure generated in the lines, which is dependent on the direction of a circulation pump. During the circulation, only a slight water pressure is generated in a line connected to the spiral spring, whereby the coil spring remains shortened in length. When pumping, however, a high pressure is generated in the line connected to the spiral spring, whereby the coil spring is extended by a lever mechanism.

A disadvantage of the described arrangement is that the self-cleaning of the filter can only take place when changing from one to the next wash program section. However, if the filter is acted upon during a Spülprogrammabschnitts with a large amount of impurities, it can not be circulated by the pump enough rinse liquid for applying the dishes. The proposed arrangement therefore accepts that the cleaning effect of individual rinse program sections may be lowered.

From the DE 36 33 441 A1 a device for wet washing garments is known, which has a designed as a gap filter lint filter and a fine filter. The lint filter consists of wires running parallel to one another and is arranged such that a liquid inlet opening above the upper end of the wire layer and one of two liquid outlet openings optionally immediately behind located at the bottom of the wire layer. The other outlet opening of the split filter leads to the inlet side of the feed pump and is located at any point of the bottom portion of the lint filter housing. The slit filter makes it possible to slip in the continuous passage of the washing water in several program sections supplied lint along the parallel wires to the lower end of the wire layer in front of the closable liquid outlet opening. From there, the impurities (lint) at the end of the program sections are washed by opening the liquid outlet through the effluent wash water with into the sewer. The fine filter only serves to retain washed out of the garments detergent in this.

Since the impurities in the operation of a dishwasher vary much more in terms of their size and texture than is the case with the cleaning of garments, which is in the DE 36 33 441 A1 filter can not be used in a dishwasher described. In addition, as with the US 3,179,116 the disadvantage that a cleaning of the filter is only possible during the transition from a wash program to the next wash program.

From the EP 0 990 413 A1 For example, a method for filtering the rinsing liquid in a dishwasher is known. In this case, the flow of rinsing liquid from the container is sucked by a main circulating pump and introduced via a plurality of spray nozzles back into the container. The stream is passed through a circuit comprising a primary screen and a perforated basket which serve to retain large debris and a chamber. The chamber is located below the primary screen and surrounds the basket at least partially. For retaining fine dirt particles, the chamber has a filter element. The method also includes a step of aspirating a portion of the flow of irrigation fluid at a point in the circuit downstream of the filter element and / or the primary screen by means of a suitable booster pump and directing the aspirated portion to an additional filter element. to retain fine dirt particles. After filtering, this part is returned to the flow of rinse liquid.

From the DE 29 45 929 A1 is a self-cleaning sieve for a dishwasher known, which consists of two discs, a plurality of parallel to each other have running, narrow slots. In this case, a disc sits stationary in the liquid flow, while the other disc is guided parallel to the first disc depending on the flow direction at this fitting or lifted. Both discs are offset relative to each other with respect to the slot direction by about 90 °.

From the DE-OS 2 249 603 as well as the DE-OS 29 22 549 Finally, filters are known for large industrial use, which have self-cleaning properties due to their variable filter spacings or - diameter.

The object of the present invention is to provide a dishwasher which makes manual cleaning of a filter element used for retaining impurities superfluous, wherein the qualitative properties of the dishwasher should be optimized in terms of energy consumption and cleaning performance.

This object is achieved by a dishwasher with the features of claim 1. Advantageous embodiments will be apparent from the dependent claims.

In a dishwasher according to the invention with at least one substantially closed water cycle in the rinsing liquid in accordance with a program control unit is circulated, the rinsing liquid during circulation for filtering impurities by at least one filter element is conveyed. In this case, the at least one filter element consists of thread elements which are arranged in a tensioned state for cleaning the rinsing liquid and in a relaxed state for cleaning the filter element.

In a further embodiment, the thread elements are arranged on holding elements and in the tensioned state substantially in a plane or in a curved shape, for. B. cylindrical shape arranged.

According to one embodiment, a further water circuit is provided in the dishwasher, through which the rinsing liquid is circulated in accordance with the program control unit, when the filter element is covered with impurities, to effect the removal of dirt from the filter element. The provision of another water cycle advantageously makes it possible to carry out the self-cleaning of the filter element during a wash program section, without the need for pumping out the dishwashing liquid currently being used in the dishwasher. The provision of the further water cycle further reliably prevents contaminants detached from the filter element from migrating into the closed water loop, thereby avoiding the settling of these dissolved contaminants on the items to be washed.

In an expedient embodiment, the filter element is installed on or in a sump of the dishwasher such that it is well bathed by the rinsing liquid flowing or conveyed in the further water cycle. This ensures that all or at least a large part of the impurities that have settled on the filter element can be solved by the rinsing fluid circulated in the further water cycle.

In a further embodiment, the filter element has a variable mesh or gap width for providing a first and a second operating state, wherein the filter element in the first operating state, the filtering of impurities from the impurities in the water circulation carries out and in the second operating state, the release of the in the filter element trapped impurities when flowing through the funded by the further water circulation rinsing allows. Through the use of such a filter element, the cleaning of impurities is facilitated, as are easily removable by an altered mesh or gap width, in particular an increase, residues when flowing through the filter element with rinsing liquid. By contrast, by setting a narrow mesh or gap width, a spatially uniform layer of the filtration material is formed, which has a large absorption capacity and enables a high degree of cleaning of the rinsing liquid during circulation in the closed water cycle.

In a further embodiment, it is provided to arrange a further filter element in the further water cycle. Characterized the detached from the filter element impurities are held in the further filter element of the further water cycle, whereby the flushing liquid flowing through the filter element with increasing continuation of the circulation in the further water cycle freed from more and more residues is. In other words, this means that the impurities from the closed water circuit, the sump and the filter element are eliminated, as a result, the wash ware is always applied with the best possible filtered rinsing liquid. In addition, the flushing performance is not affected by an increasingly clogging filter element, since by actuation of the further water cycle, a filter element with constant filter performance is created.

Conveniently, the further filter element is arranged in a collecting container. This makes it possible to collect the promoted in the wider water cycle impurities.

In a further embodiment, the further filter element has a variable mesh or gap width for providing a first and a second operating state, wherein the further filter element in the first operating state, the filtering of impurities promoted in the further water circulation rinse liquid and in the second operating state, the release of the Impurities trapped in the further filter element when flowing around the further filter element with rinsing liquid of the further water cycle. In other words, therefore, the further filter element is designed to be self-cleaning. This ensures a constant filtering performance of the second filter element during operation of the further water cycle.

According to another embodiment, the further water circuit is integrated into a water drain, so that the conveyed in the further water circulation rinse liquid can be supplied according to the program control unit either the dishwasher or the wastewater drain. In this case, the further water circuit is advantageously operated such that the further filter element is in the first operating state when the rinsing liquid is circulated in the dishwasher. Accordingly, the further filter element is in the second operating state in which this allows a cleaning, wherein the impurities are supplied to the water drain. After a "temporary storage" of the impurities in the further filter element or the collecting container, the impurities are transported out of the dishwasher.

A method for operating a dishwasher with a program program comprising several program sections, comprises the following steps: The filter element is operated during the course of the wash program in a first operating state, in which this takes over a filtering of the washing liquid of impurities of the closed water cycle. In accordance with the program control unit or upon detection of a defined occupancy of the filter element with impurities of the further water cycle is activated and brought the filter element in a second operating state for detachment of impurities present in or on it. In one embodiment of the operating method, the second filter element is operated in activated further water circuit in its first operating state to free the conveyed in the further water circulation rinsing fluid from impurities.

In another embodiment of the operating method, the further filter element is spent after completion of the wash program or in accordance with the program control unit in a second operating state in which the impurities located on or in the further filter element are flushed out of the further filter element by the rinsing liquid conveyed in the further water cycle ,

According to a further embodiment of the operating method, the rinsing liquid conveyed in the further water cycle is supplied to the water outlet during the second operating state of the further filter element.

The dishwashing machine according to the invention thus advantageously makes it possible to carry out a self-cleaning of the filter element of the closed water circuit during a wash program section instead of basically waiting for the wash program end, as proposed in the prior art. As a result, the cleaning performance during a Spülprogrammabschnitts be kept at a consistently high level without the dishwasher additional fresh water would have to be supplied.

Fig. 1

eine schematische Darstellung einer Geschirrspülmaschine mit einem weiteren Wasserkreislauf,

Fig. 2a, 2b

eine schematische Darstellung eines beispielhaft in der in Fig. 1 dargestellten Geschirrspülmaschine einsetzbaren Filterelements in einer Seitenansicht und einem Querschnitt, wobei das Filterelement in einem ersten Betriebszustand dargestellt ist, und

Fig. 3a, 3b

eine schematische Darstellung eines beispielhaft in der in Fig. 1 dargestellten Geschirrspülmaschine einsetzbaren Filterelements in einer Seitenansicht und einem Querschnitt, wobei das Filterelement in einem zweiten Betriebszustand dargestellt ist.

The invention and its advantages will be explained in more detail by way of example with reference to the drawing. Show it:

Fig. 1

a schematic representation of a dishwasher with another water cycle,

Fig. 2a, 2b

a schematic representation of an example in the in Fig. 1 illustrated dishwasher filter element in a side view and a cross section, wherein the filter element is shown in a first operating state, and

Fig. 3a, 3b

a schematic representation of an example in the in Fig. 1 shown dishwasher filter element in a side view and a cross section, wherein the filter element is shown in a second operating state.

In Fig. 1 a dishwasher 1 is shown in a schematic view. The dishwasher 1 essentially comprises a washing compartment 2, in which not shown Dishware is arranged, a Spülflüssigkeitskreislauf 6, a (not shown in the figure) water inlet and a water outlet 11. The items to be washed is arranged in the washing compartment 2 between washing or spraying 3. Below the items to be washed and the washing arms 3, a rinsing pan 4 is arranged, which passes rinsing liquid present in the washing compartment in a sump 5. The sump 5 belongs to the rinsing liquid circuit 6, in which the rinsing liquid 7 required for a washing process is circulated. During a washing process, which may include the program sections pre-rinsing, cleaning, intermediate rinsing and rinsing, the sump 5 is removed via a line 8 rinsing liquid and passed through a filter element 14 to a pump 9. From the pump 9, the rinsing liquid is passed through lines 10 to the washing arms 3 after passing through a water heater (not shown) and sprayed by them into the washing compartment 2. In the washing compartment 2, the rinsing liquid 7 then passes through the rinsing tank 4 back into the sump 5. With the sump 5, the water outlet 11 is connected, via which the rinsing liquid can be derived. For example, a portion of the rinsing liquid or the entire rinsing liquid is discharged via the water outlet 11 after each wash cycle. A filling of the sump is done with the help of the water inlet, which provides fresh water. In addition, the dishwasher 1 may have further, not shown in the figure elements, such as a device for the addition of detergent, a water softening system, sensors and the like.

By applying the rinsing with rinsing liquid impurities are removed from this, which initially collect in the sump 5, to then be filtered by the operation of the pump 9 in the filter element 14 from the circulating rinsing liquid. Depending on the degree of soiling of the items to be washed or the number of wash program sections already carried out, the filter element 14 is more or less exposed to impurities. Under certain circumstances, this can lead to insufficient pumping liquid being able to be conveyed out of the sump 5 by the pump 9, as a result of which the wash ware is consequently subjected to less washing liquid, so that the wash result worsens.

In order to avoid a manual cleaning of the filter element 14, this is designed as a self-cleaning filter element. Such a self-cleaning filter element is exemplary in the Figures 2 and 3 shown, in Fig. 2 a first operating state is shown, in which a filtering of the conveyed through it rinsing liquid is effected. FIG. 3 shows the filter element in a second operating state in which a self-cleaning is possible. The filter elements shown in the figures are traversed perpendicular to the sheet plane.

The filter element has for this purpose in a trained with guides 31 housing 30 holding elements 32, between which thread elements 33, for example made of metal, a plastic or other material, are arranged. By tensioning the thread elements 33 is formed in Fig. 2a shown parallel alignment with a defined distance from each other. Depending on the desired filter effect, the distance can be defined by fastening the thread elements 33 in the holding elements 32. The tensioning and relaxing of the thread elements 33 with the holding elements 32 via corresponding devices, for. As spindles or hydraulic devices. In the side view of Fig. 2b It can be seen that all thread elements 33 lie in one plane, whereby a good filtering effect is ensured. If at least one of the two holding elements 32 is moved in the direction of the other holding element, then the thread elements 33 can relax in the manner shown in the figure, whereby the distances are increased in more or less random manner. When flowing through the filter element with rinsing liquid in the second operating state, the impurities held on or in it can then be rinsed out.

The self-cleaning process of the filter 14 can either be controlled by a program control unit (not shown in the figures) or upon detection of a defined occupancy of the filter element 14. With increasing occupancy of the filter element 14, the funded by the pump 9 flushing liquid is reduced. By the measured after the filter element 14 funded amount of flushing liquid can then be closed to the assignment of the filter element.

To clean the filter element 14, as in connection with the Fig. 3 described, the filter element 14 spent in its second operating state. At the same time a further pump 13 is set in motion, which promotes the flushing liquid 7 located in the sump 5 by a further water circuit 15. The pump 13 is located in the further water circuit 15, which also has a collecting container 16, in which a further filter element 17 is arranged. On the output side is the Sump 16 via a valve 18 selectively connected to the water outlet 11 or a line 20 which promotes circulating in the further water circulation 15 rinsing liquid back into the sump 5.

In order to be able to effect a self-cleaning of the filter element 14, it must be flowed around in a suitable manner by the rinsing liquid conveyed through the further water circuit 15. In practice, the filter element 14 will therefore be arranged at a suitable location in the conduit 8 or directly on or in the sump 5.

The detached from the filter element 14 impurities are collected via the pump 13 and the line 19 through the further filter element 17, which is preferably also carried out self-cleaning. The funded by the further water circulation 15 rinsing liquid is thus cleaned at the outlet of the collecting container 16, and, if the water cycle was actuated during a Spülprogrammabschnitts, fed to the sump 5. After a certain period of time, the further water circuit 15 can be deactivated, at the same time the filter element 14 is returned to its first operating position. Subsequently, the interrupted rinse program section can be continued. Of course it is also possible to carry out the self-cleaning of the filter element 14 at the end of a washing program section. In this case, for example, the rinsing liquid cleaned by the further filter element 17 could be taken for the next rinsing program section, so that the supply of fresh water could be dispensed with.

Since now detached from the items to be washed contaminants are trapped in the other filter element 17, and the cleaning effect of the other filter element 17 deteriorates with increasing operating time of the further water circuit 15, a self-cleaning of the further filter element 17 always takes place when the rinsing liquid of a Spülprogrammabschnitts the Water outlet 11 is to be supplied. With the appropriate switching of the valve 18 thus the further filter element is set in its second operating state, so that the pumped from the sump 5 via the pump 13 rinsing liquid can replace the trapped in the other filter element 17 impurities, which is then fed to the water outlet.

LIST OF REFERENCE NUMBERS

1 dishwasher 2 Wash cabinet 3 spray arm 4 wash tub 5 sump 6 Water cycle 7 rinse 8th management 9 pump 10 management 11 water drain 13 pump 14 filter element 15 Water cycle 16 Clippings 17 filter element 18 Valve 19 management 20 management 30 filter housing 31 guide element 32 retaining element 33 thread element

Claims (9)

1. Dishwasher (1) with at least one essentially closed water circuit (6) in which rinsing liquid (7) can be circulated according to the program control unit, it being possible during circulation to convey said rinsing liquid through at least one filter element (14, 17) for the purposes of filtering out dirt, characterised in that at least one filter element (14, 17) consists of thread elements (33) which are arranged under tension for cleaning of the rinsing liquid (7) and in a relaxed state for cleaning the filter element (14, 17).
2. Dishwasher (1) according to claim 10, characterised in that the thread elements (33) are arranged on securing elements (32), and when under tension are essentially arranged in one level or in bent form, for example cylindrical form.
3. Dishwasher (1) according to claim 1 or 2, characterised in that a further water circuit (15) is provided, through which rinsing liquid (7) can be circulated according to the program control unit, if the filter element (14) is dirty, in order to effect cleaning of the filter element (14).
4. Dishwasher according to claim 3, characterised in that the filter element (14) is built onto or into a pump well (5) of the dishwasher in such a way that this is capable of being well flushed by the rinsing liquid flowing in the further water circuit (15).
5. Dishwasher according to claim 3 or 4, characterised in that the filter element (14) has a variable mesh or column width for the provision of a first and a second operating state where the filter element carries out the filtering of dirt from that located in the water circuit (6) in the first operating state, and in the second operating state enables loosening of the dirt trapped in the filter element (14) upon circumflow of the rinsing liquid supplied through the further water circuit (15).
6. Dishwasher according to one of claims 3 to 5, characterised in that the further water circuit (15) has a further filter element (17).
7. Dishwasher according to one of claims 3 to 6, characterised in that the further filter element (17) is arranged in a collection receptacle (16).
8. Dishwasher according to claim 6 or 7, characterised in that the further filter element (17) has a variable mesh or column width for the provision of a first and a second operating state where the further filter element (17) carries out the filtering of dirt from the rinsing liquid located in the water circuit (15) in the first operating state, and in the second operating state enables loosening of the dirt trapped in the further filter element (17) upon circumflow of the further filter element (17) with rinsing liquid of the further water circuit (15).
9. Dishwasher according to one of claims 3 to 8, characterised in that the further water circuit (15) is integrated into a water outlet (11) so that the rinsing liquid conveyed in the further water circuit (15) can be conducted according to the program control unit optionally to the water-conducting household appliance or the water outlet (11).

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