EP2566378B1 - Dishwasher with a screen system - Google Patents

Description

The present invention relates to a dishwasher, in particular a domestic dishwasher, with a control device for performing a rinse cycle for cleaning items to be washed, comprising a sieve system for filtering a rinsing liquid, which has a circulation chamber and a collecting chamber communicating with the circulation chamber via a sieve arrangement through which the rinsing liquid can flow with a connection arranged at the circulation chamber for a circulating pump for circulating the rinsing liquid and with a collecting chamber arranged at the connection for a drain pump for pumping out the rinsing liquid.

A dishwashing machine is known from practice, which has a screen system for filtering a rinsing liquid with a sieve arrangement through which the rinsing liquid can flow.

If the sieve arrangement is blocked, for example by dirt particles filtered out of the rinsing liquid, this can lead to disruptions in the operation of the dishwasher.

From the EP 1 464 268 A2 is a method for detecting the loading of a sieve system of a dishwasher, which comprises a circulation loop with a sieve system and a circulation pump for circulating the rinsing liquid known. In this case, at least one, a level of the rinsing liquid associated first value of a process variable and at least one, a level of the rinse liquid associated second value of the process variable or at least one, corresponding to a first value of a process variable first level of the rinsing liquid and / or at least one second value of the process variable corresponding to the second level of the rinsing liquid determined at least one load characteristic and used as a measure of the Siebbeladung. In this case, the process variable is uniquely related to the rotational speed of the circulation pump and is in particular a circulation pump speed, a circulation pump delivery pressure, an electrical delivery rate of the circulation pump, a mechanical delivery rate of the circulation pump, a volume of the rinsing liquid or a volume flow of the rinsing liquid or a flow rate of the rinsing liquid.

From the US 2003/0019510 A1 For example, a dishwasher with a rinse tank, a filter for filtering water in the rinse tank, a sensor in flow communication with the rinse tank, and a liquid loop for circulating water in the rinse tank are known. A control mechanism, which is coupled to the sensor and the liquid circuit, is set up to determine on the basis of the sensor signal whether a blockage of the filter is present or is to be expected and, if necessary, to take corrective measures.

From the DE 10 2005 058250 A1 For example, a dishwasher is known which comprises a reservoir for receiving water connected to a tub, a water supply pump for pumping the water into the collection container, a filter device for receiving a portion of the water which is pumped through an additional passage to filter the pumped water and returning the filtered water to the sump, and having a bypass for diverting water to be supplied to the filter device to the tub or sump when the filter device is clogged by garbage.

The object of the present invention is to provide a dishwasher, in particular a domestic dishwasher, with increased operational reliability.

The object is achieved in a dishwasher of the type mentioned above in that the rinse comprises at least one performed by the control device detection sequence for detecting clogging of the sieve assembly, wherein a first measuring step for determining a transmittance in the filled with the rinsing fluid circulation chamber by means of an optical turbidity sensor is provided, wherein after the first measuring step, a first Abpumpschritt is provided for pumping the rinsing liquid from the collection chamber, wherein after the first Abpumpschritt a second measuring step for determining the transmittance in the circulation chamber by means of the optical turbidity sensor is provided, and wherein a first evaluation step for evaluating a change in the transmittance from the first measuring step to the second measuring step is provided.

The dishwasher according to the invention has a control device for automatically carrying out operating sequences of the dishwasher. For this purpose, the control device can be designed as so-called sequence control, in particular as electronic sequence control.

In the control device, at least one rinse program for performing or controlling a rinsing process, also called rinse cycle, for rinsing items to be washed, in particular for rinsing dishes, deposited. Advantageously, several wash programs are provided, one of which can be selected and started by the operator. This makes it possible to adjust the sequence of a wash cycle, in particular to the load, to the type of loading, to the degree of soiling of the items to be washed and / or to the desired duration of the wash cycle.

The stored washing programs may preferably be designed such that the respective wash cycle controlled by them in particular at least one pre-rinse for pre-cleaning items, at least one cleaning operation for thoroughly cleaning items, at least one intermediate rinse for removing soiled rinse liquid from the items to be washed, at least one rinse cycle to avoid of stains on the items to be washed and / or for preparing a drying step, and / or at least one drying course for drying the items to be washed. Rinse cycle, cleaning cycle, intermediate rinse cycle and rinse cycle are referred to as water-carrying partial rinses, since during their implementation, the introduced into the rinsing chamber items to be treated with a rinsing liquid. During the drying cycle, a use of rinsing liquid is usually not provided.

The treatment of the items to be washed with rinsing liquid takes place in a substantially complete rinsing chamber, in particular a rinsing container, the dishwasher. In this case, the flushing chamber may be associated with an inlet valve, which allows to fill flushing liquid in the washing chamber. That's it Inlet valve can be opened and closed by the control device, so as to influence the inflow of rinsing liquid.

A rinsing liquid is understood here to mean, in particular, a liquid which is intended to be applied to the ware in order to clean it and / or to treat it in another way. For example, the rinsing liquid can also be provided for heating the items to be washed, which is customary, for example, during a rinsing step.

The rinsing fluid entering the rinsing chamber via the inlet valve is usually inflow water. Depending on the operating phase of the dishwasher, the rinsing liquid in the rinsing chamber can be enriched with cleaning agents, with cleaning aids, such as, for example, rinse aid and / or with dirt which has been removed from the items to be washed. But there are also cases conceivable in which already enriched water is filled as flushing liquid via the inlet valve in the washing chamber.

In order to clean the rinsing liquid, in particular during a rinse cycle of dirt particles, a screening system with a circulation chamber and a collection chamber is provided, which may be arranged in particular at a bottom of the rinsing chamber, also called rinsing pan, so that the rinsing liquid in the rinsing chamber automatically by their Weight force flows to the sieve system. The circulation chamber and the collection chamber are separated by a sieve arrangement, which can be flowed through by the rinsing liquid to be filtered. In this way, an undisturbed operation of the dishwasher, an exchange of rinsing liquid is possible, so that automatically adjusts a substantially identical level of rinsing liquid in both chambers. If, for example, rinsing liquid is removed from the circulation chamber via the connection of the circulation chamber, so that the level of rinsing liquid in the circulation chamber drops, rinsing liquid flows from the collection chamber through the sieve arrangement into the circulation chamber as a result of the weight force, so that the fill levels in the circulation chamber and the Balance collection chamber. Conversely, if, for example, rinsing liquid is removed from the collecting chamber via a connection of the collecting chamber, rinsing liquid from the circulating chamber flows through the sieve arrangement into the collecting chamber. Such an arrangement of Circulation chamber and the collection chamber, in which a compensation of the levels due to the weight force is also referred to as a communicating arrangement.

The sieve arrangement separating the circulation chamber and the collection chamber may consist of one or more sieves. For example, a sieve arrangement which has an upright cylindrical fine sieve and a concentrically arranged cylindrical micro sieve on the outside thereof is customary. In this case, the microsieve is provided for removing micro-dirt particles from the rinsing liquor. The use of a fine sieve allows pre-cleaning of the rinsing liquor. Finer micro-dirt that has passed through the fine screen can then be retained at least partially with the microsieve. Due to the two-stage design of the sieve arrangement, the blockage tendency of the sieve arrangement can in principle be reduced, but not always excluded.

Typically, the connection of the circulation chamber is connected to an electrically driven circulating pump for circulating the filled flushing liquid, which makes it possible to remove the flushing liquid in the circulation chamber and apply it to the washware via a spraying system assigned to the flushing chamber. Likewise, the connection of the collecting chamber with a usually electrically driven drain pump for pumping out the filled rinsing liquid to the outside, also called sewage pump may be connected. It is also conceivable, however, that the connection of the circulation chamber and the connection of the collection chamber via a valve assembly, a water gate or the like are alternately connected to such a pump, which takes over depending on the circuit of the valve assembly, etc. either the function of the circulation pump or the function of the drain pump ,

The circulating pump may, like the drain pump, preferably comprise a brushless electric motor. The brushless electric motor can be designed in particular as a permanent magnet motor. Such a brushless permanent magnet motor may be formed, for example, as a brushless DC motor, also called a BLDC motor, or as a brushless AC motor, also called a BLAC motor. The rotor of the motor comprises at least one Permanent magnets, whereas the stator has a plurality of electromagnets. The electromagnets are commutated via a control electronics, in particular via a frequency converter. Compared to other possible engine concepts, this allows both the direction of rotation and the speed of the engine to be controlled in a simple manner. By operating the motor in exactly one direction of rotation, it is possible to optimize the fluid-carrying parts of the circulating pump or the drain pump. This results in a high flow rate with low energy consumption. Furthermore, the brushless permanent magnet motor can be designed as a wet rotor, so that complex sealing measures are eliminated.

The dishwashing machine according to the invention is now designed so that at least one detection sequence for detecting clogging of the sieve arrangement is carried out by the control device during a wash cycle. In this case, for example, at the end of a water-conducting Teilspülgangs, filled with rinsing liquid circulation chamber, a first measuring step is performed in which by means of an optical turbidity sensor, a transmittance in the circulation chamber is determined.

The turbidity sensor usually comprises a light source, for example a light-emitting diode, and a light receiver, for example a phototransistor, which are arranged such that the light emitted by the light-emitting diode passes through the medium respectively located in the circulation chamber, that is, as a rule rinsing liquid or air hits the light receiver. In this case, the turbidity sensor for determining the transmittance of the medium is formed, that is, for determining the ratio of the intensity of the received light to the intensity of the emitted light, wherein the intensity is the power of the light per area. For the purposes of this application, however, the term "determination of the degree of transmittance" should also be understood to mean the determination of quantities which contain the same technical information in a different formulation. This includes, in particular, the determination of the so-called opacity, that is to say the determination of the reciprocal of the above-defined transmittance, or the determination of the so-called extinction, which is a logarithmic formulation of the opacity.

Furthermore, as part of the recognition sequence after the first measuring step, a first Abpumpschritt for pumping out the rinsing liquid via the connection of the collection chamber is provided. If there is no blockage of the sieve arrangement, the rinsing liquid located in the circulation chamber is thereby also pumped out, so that the circulation chamber is essentially filled with air after the pumping-off step. However, if there is a blockage, at least part of this rinsing liquid remains in the circulation chamber.

After the first pumping off step, a second measuring step is provided for the renewed determination of the transmittance in the circulation chamber by means of the optical turbidity sensor. By a first subsequent evaluation step for evaluating a change in the transmittance from the first measuring step to the second measuring step, a statement can now be made as to whether the rinsing liquid was pumped out of the circulation chamber in a sufficient manner by the first pumping step, since the transmittance at a transition of the metered medium from rinse liquid to air changes significantly. This in turn allows a statement as to whether the filter assembly is clogged or not.

In this way it can be prevented that after a pumping down operation during the wash cycle, for example at the end of a water-carrying Teilspülgangs unrecognized remains a usually contaminated residual amount of washing liquid in the sieve assembly, which would worsen the wash result of the wash cycle or a subsequent wash cycle. Thus, the detection of a blockage allows the initiation of appropriate countermeasures. In this way, the reliability of the dishwasher according to the invention can be increased.

The recognition accuracy is higher than in such detection sequences in which the degree of contamination of the rinsing liquid, ie their turbidity determined by the transmittance and closed on reaching a defined degree of contamination on a blockage, as well as a strong turbidity, in particular by many but fine dirt particles, does not necessarily lead to constipation. This can lead to many misrecognitions in such recognition sequences.

The recognition accuracy is higher than in such detection sequences, in which, without measuring the degree of transmission after Abpumpschritt the circulation pump is turned on and their power consumption is compared with a threshold value, with an exceeding of the threshold value is interpreted as constipation. Although a high power consumption indicates an undesirably high level of flushing liquid in the circulation chamber, a defined threshold value can nevertheless be exceeded even if the level is too high or there is no blockage. Reasons for this can be, for example, in the series spread of the circulation pump and / or in an aging of the circulation pump, which can lead to many false detections.

In addition, the requirements for the structural design of the dishwasher are low. In many cases, the required design features are already present, so that the invention can be realized by a corresponding adjustment of the control device.

According to the invention, if there is a decrease in the transmittance by at least a first minimum value, an abort of the recognition sequence. Termination of the recognition sequence is understood here to mean a termination thereof in which blockage of the sieve arrangement is regarded as being excluded. The degree of transmission is about 30% higher in clear rinsing fluid than in air. Furthermore, depending on the degree of soiling, the degree of transmission in contaminated rinsing liquid is usually in a range between approximately 30% and 10% above that in air. If there is a decrease by a suitably set minimum value, it can be ruled out with great certainty that the decrease in the transmittance can be attributed to additional and sudden soiling of the rinsing liquid. Consequently, in this case, it is highly probable that a rinse liquid to air transition has occurred during the first pump down step, which ultimately means that the filter assembly is not clogged with great certainty. Error detection of blockages can be safely prevented. For example, the first minimum value may be a decrease of at least 10%.

According to an advantageous development of the invention, the first draining step comprises a load detection step for detecting a power consumption of the drain pump, wherein, if the power consumption is greater than a threshold value provided for the drain pump, the detection sequence is aborted. If a suitably defined threshold is exceeded, this indicates that there is still rinsing liquid in the collection chamber after the end of the pumping step. In this case, the rinsing liquid present in the circulation chamber prior to the first pumping step can not run off, even if the sieve arrangement is continuous, so that if the recognition sequence is continued, an incorrect detection of a blockage would occur. This can be prevented by aborting the recognition sequence.

According to an advantageous development of the invention, if an interruption of the detection sequence takes place in the load detection step for detecting the power consumption of the drain pump, an error treatment sequence is provided for handling a malfunction of a drainage device arranged downstream of the drain pump. If, after the first pumping step, rinsing liquid is still present in the collecting chamber, this is generally attributable to a malfunction of a drainage device arranged downstream of the drainage pump. By now triggering a corresponding error treatment sequence, it is possible to prevent the malfunction from remaining unrecognized. In particular, the error handling sequence may include issuing a warning message to an operator.

According to an expedient development of the invention, a load recognition step for detecting a power consumption of the circulation pump is provided between the first pumping-off step and the second measuring step, wherein, if the power consumption is smaller than a threshold value provided for the circulation pump, the detection sequence is aborted. A power consumption below a suitably fixed threshold indicates with high probability that the circulation chamber is sufficiently emptied after the first pumping step to conclude that the filter arrangement is continuous. The termination of the detection sequence in this case simplifies the course of the rinse without affecting the detection reliability of blockages. If the specified threshold is exceeded, although not too high or no Blockage is present, this is detected in the subsequent first evaluation step, so that an error detection of a blockage is excluded.

According to an expedient development of the invention, a first waiting step is provided between the first pumping step and the load detection step for detecting the power consumption of the circulation pump. In this way, an error detection of the power consumption of the circulation pump due to transient processes can be prevented, which further improves the detection reliability.

According to an expedient development of the invention, if an interruption of the detection sequence takes place in the load detection step for detecting the power consumption of the circulation pump, after the load detection step for detecting the power consumption of the circulation pump, an adaptation step for redetermining the threshold provided for the circulation pump is provided, in which the power consumption of the circulation pump measured and a new threshold from the measured power consumption is determined. In this case, the measurement of the power consumption of the circulating pump takes place with empty circulation chamber. In this way, a change in the power consumption of the circulating pump in dry running, so if it does not promote flushing, which is due to aging phenomena, be taken into account in a later implementation of the recognition sequence. The redetermination of the threshold value can be done, for example, by adding the measured power consumption and a safety value. It is also possible to multiply the measured power consumption with a safety factor.

According to an expedient development of the invention, a second pumping off step for pumping out the rinsing liquid via the connection of the collecting chamber is provided between the load detection step for detecting the power consumption of the circulation pump and the adaptation step. In this way, a falsification of the measurement of the power consumption of the circulating pump in dry running is avoided by residual water, which improves the accuracy of the new threshold.

According to an advantageous embodiment of the invention, a third Abpumpschritt is provided for pumping out the rinsing liquid via the connection of the collecting chamber between the load detection step for detecting the power consumption of the circulation pump and the second measuring step. This avoids a falsification of the measurement of the transmittance in the second measurement step by residual water collecting during the load detection step, which improves the accuracy of the detection of the transmittance and thus the reliability of detection.

According to an advantageous development of the invention, a second waiting step is provided between the load detection step for detecting the power consumption of the circulation pump and the third pumping step. In this way, in particular a falsification of the detection of the transmittance in the second measuring step by foaming in the load detection step can be avoided, which further improves the detection reliability.

According to an advantageous development of the invention, if the decrease in the transmittance determined in the first evaluation step is less than the first minimum value, after the second measuring step a rinsing liquid supplementing step is provided in which an additional amount of rinsing liquid is supplied to the sieve system, wherein after the rinsing liquid supplementing step a third Measuring step is provided for determining the transmittance in the circulation chamber by means of the optical turbidity sensor, wherein a second evaluation step is provided for evaluating a change in the transmittance of the second measuring step to the third measuring step, wherein, if there is an increase in the transmittance by at least a second minimum value, a termination the recognition sequence takes place.

If the decrease in the transmittance determined in the first evaluation step is less than the first minimum value, this may be due to the fact that either the rinsing liquid did not run out of the circulation chamber during the first and third pumping steps, which would be interpreted as a blockage of the sieve arrangement, or the rinsing liquid was so heavily soiled during the first measuring step that due to its low transmittance of the first minimum value, ie the minimum decrease of the first measured transmittance to the second measured transmittance, despite a transfer of rinse liquid to air, which would be interpreted as a lack of clogging, is not achieved. In order to be able to differentiate between these two cases, the screening system is supplied with an additional amount of rinse liquid that is as clear as possible. For example, this can be supplied via the inlet valve inlet water. Now, a third measurement step for determining the transmittance is performed and its measured transmittance compared with the transmittance of the second measurement step. If there is now a minimum increase of, for example, 10%, it can now be concluded that no rinsing liquid was in the circulation chamber in the second measuring step, which is a clear indication that the sieve arrangement is not blocked. In this case, the detection sequence can be aborted.

According to an expedient development of the invention, if the detection sequence is aborted during the first evaluation step, after the first evaluation step an adaptation step is provided for redetermining the threshold value provided for the circulation pump, wherein the power consumption of the circulation pump is measured and a new threshold is determined from the measured power consumption is. Also in this case, the measurement of the power consumption of the circulating pump takes place with emptied circulation chamber. In this way, a change in the power consumption of the circulating pump in dry running, so if it does not promote flushing, which is due to aging phenomena, be taken into account in a later implementation of the recognition sequence. The re-determination of the threshold value can also be done by adding the measured power consumption and a safety value. It is also possible to multiply the measured power consumption with a safety factor.

According to an advantageous development of the invention, if the increase in the transmittance determined in the second evaluation step is less than the second minimum value, after the second evaluation step a fourth pumping step is provided for pumping out the rinsing liquid via the connection of the collecting chamber, wherein after the third pumping step a fourth measuring step is provided for determining the transmittance in the circulation chamber by means of the optical turbidity sensor, and wherein a third evaluation step for evaluating a change the transmittance from the third measuring step to the fourth measuring step is provided, wherein, if there is a decrease in the transmittance by at least a third minimum value, an abort of the detection sequence is carried out. If the increase in the transmittance determined in the second evaluation step is less than the second minimum value, this may be due to the fact that either the rinsing liquid did not run out of the circulation chamber during the first and third pumping steps, which would be interpreted as blockage of the sieve arrangement, or the rinsing liquid supplied during the rinsing liquid supplementation step was so heavily soiled that due to its low transmittance, the second minimum value, ie the minimum increase from the second measured transmittance to the third measured transmittance, despite a transition from air to rinsing liquid, would be interpreted as a lack of clogging , is not reached. In order to be able to distinguish between these two cases, a fourth pumping step and a fourth measuring step for determining the transmittance are carried out. Thereupon the decrease from the third transmittance to the fourth transmittance is determined. This result can deviate from the result of the first evaluation step, since at the beginning of the third measuring step, due to the rinsing liquid supplementing step, clearer rinsing liquid is generally located in the circulating chamber than in the first measuring step. If a minimum decrease of, for example, 7% now results, it can now be concluded that in the fourth measuring step no rinsing liquid was located in the circulation chamber, which is a clear indication that the sieve arrangement is not blocked. In this case, the detection sequence can be aborted.

According to an advantageous development of the invention, in the third evaluation step, a decrease in the transmittance is interpreted as less than the third minimum value as blockage of the sieve arrangement, wherein an automatic cleaning sequence and / or a warning message is triggered by the control device. In such a detection of a blockage of the sieve arrangement an error detection is almost impossible. It is advantageous if an automatic sequence to eliminate the blockage is provided. Also, an automatic sequence for issuing a warning message may be issued so that an operator can manually remove the blockage.

Furthermore, the invention relates to a method for operating a dishwasher, in particular according to one of the preceding claims, with a control device for performing a wash cycle for cleaning items to be washed, with a screen system for filtering a rinsing liquid, which a circulation chamber and with the circulation chamber via one of The flushing liquid flow through the sieve arrangement communicating collecting chamber having a arranged on the circulation chamber connection for a circulating pump for circulating the rinsing liquid and with a arranged at the collection port connection for a drain pump for pumping out the rinsing liquid.

In the method according to the invention, it is provided that during the wash cycle by the control device at least one detection sequence for detecting a blockage of the screen assembly is performed, wherein a first measuring step for determining a transmittance in the circulation chamber filled with the rinsing liquid is provided by means of an optical turbidity sensor the first measuring step, a first Abpumpschritt is provided for pumping the rinsing liquid through the connection of the collection chamber, wherein after the first Abpumpschritt a second measuring step for determining the transmittance in the circulation chamber is provided by the optical turbidity sensor, and wherein a first evaluation step for evaluating a change of Transmittance from the first measuring step to the second measuring step is provided. In this case, if there is a decrease in the transmittance from the first measuring step to the second measuring step by at least a first minimum value, an abort of the recognition sequence takes place. Termination of the recognition sequence is understood here to mean a termination thereof in which blockage of the sieve arrangement is regarded as being excluded.

The inventive method allows a simple, fast and reliable detection of clogging of the screen assembly and is characterized by low demands on the structural design of the dishwasher.

Other advantageous embodiments and / or developments of the invention are given in the claims.

The reproduced in the dependent claims and / or above advantageous embodiments of the invention may be provided individually or in any combination with each other.

Figur 1

ein Ausführungsbeispiel einer erfindungsgemäßen Haushaltsgeschirrspülmaschine in einer schematischen Seitenansicht,

Figur 2

eine weitere Darstellung der Geschirrspülmaschine der Figur 1,

Figur 3

eine vergrößerte Darstellung des Siebsystems der Haushaltsgeschirrspülmaschine der Figuren 1 und 2 sowie

Figur 4

einen Ablaufplan einer Erkennungssequenz zur Erkennung einer Verstopfung im Bereich des Siebsystems der erfindungsgemäßen Geschirrspülmaschine der Figuren 1 bis 3.

The invention and its developments and their advantages are explained in more detail with reference to figures. Show it:

FIG. 1

An embodiment of a domestic dishwasher according to the invention in a schematic side view,

FIG. 2

another illustration of the dishwasher of FIG. 1 .

FIG. 3

an enlarged view of the sieve system of the household dishwasher FIGS. 1 and 2 such as

FIG. 4

a flowchart of a detection sequence for detecting a blockage in the region of the sieve system of the dishwasher according to the invention the FIGS. 1 to 3 ,

In the following figures, corresponding parts are provided with the same reference numerals. In this case, only those components of a dishwasher are provided with reference numerals and explained, which are necessary for the understanding of the invention. It goes without saying that the dishwasher according to the invention can comprise further parts and assemblies.

FIG. 1 shows an advantageous embodiment of a household dishwasher according to the invention 1 in a schematic side view. The dishwasher 1 has a control device 2, in which at least one wash program for controlling a wash cycle for washing dishes, in particular dishes, is deposited. Expediently, a plurality of washing programs are stored, so that by selecting a suitable washing program, the sequence of a controlled by the control unit 2 rinse, for example, to the load, to the type of load, to the degree of contamination of the dishes and / or to the desired duration of the wash can be adjusted.

The control device 2 is associated with an operating device 3, which allows an operator of the dishwasher 1 to call one of the washing programs and thereby start. Furthermore, the control device 2 is associated with an output device 4, which allows the output of messages to the operator. The output device 4 may comprise indicator lamps, light-emitting diodes, an alpha-numeric display and / or a graphic display for outputting optical messages. Furthermore, the output device 4 may have a buzzer, a loudspeaker and / or the like for the output of acoustic messages.

The dishwasher 1 further comprises a rinsing container 5, which can be closed by a door 6, so that a closed rinsing chamber 7 is formed for rinsing dishes. If appropriate, the rinsing container 5 can be arranged inside a housing 8 of the dishwasher 1. In built-in dishwashers, the housing 8 is not required and may be omitted altogether at the top. In FIG. 1 the door 6 is shown in its closed position. The door 6 can be brought into an open position by pivoting about an axis arranged perpendicular to the plane of the drawing, in which it is aligned substantially horizontally and allows the introduction or removal of items to be washed. Im in FIG. 1 the embodiment shown, the operating device 3 is arranged in an easy to use manner on an upper portion of the door 6. The output device 4 is also arranged on the upper portion of the door 6, so that optical messages are clearly visible and audible messages are clearly audible. In principle, however, it is possible to arrange the operating device 3 and / or the output device 4 elsewhere.

The control device 2 is accommodated by way of example in a base assembly below the washing container 5. However, it is also possible to arrange the control device 2 at another location of the dishwasher 1. However, the control device 2 could also be configured decentralized, which is understood to include spatially separated components which are connected via communication means such that they can cooperate.

According to an alternative embodiment variant, the control device 2 or at least one of its decentralized components can be positioned in the door 6, so that the required signal connections between the operating device 3, the output device 4 and the control device 2 can be kept short.

The dishwasher 1 has an upper dish rack 9 and a lower dish rack 10 for positioning dishes. The upper dish rack 9 is arranged on extension rails 11, which are each attached to opposite, extending in the depth direction of the washing compartment side walls of the washing compartment 5. When the door 6 is open, the dish rack 9 can be moved out of the washing container 5 by means of the extension rails 11, which facilitates the loading and unloading of the upper dish rack 9. The lower dish rack 10 is arranged on extension rails 12 in an analogous manner.

The one or more stored in the control device 2 washing programs can each provide several Teilspülgänge, for example, in this order at least one prewash, at least one cleaning cycle, at least one intermediate rinse, at least one rinse and / or at least one drying cycle. Here, pre-wash cycle, cleaning cycle, intermediate rinse cycle and rinse cycle are referred to as water-carrying partial rinses, since during their implementation, the items to be washed positioned in the rinsing chamber 7 are treated with a rinsing liquid S. During the drying cycle, a treatment of the items to be washed with rinsing liquid S is generally not provided.

In the exemplary embodiment, fresh water or feed water ZW, which can be taken up by an external water supply device WH, in particular a drinking water supply network, and filled into the rinsing chamber 7, is used as rinsing liquid S for the treatment of the items to be washed. Typically, a rinsing liquid S formed from fresh feed water ZW is introduced at the beginning of each water-conducting partial rinse cycle, which rinse liquid is then discharged to the end of the respective rinse cycle to an external sanitation AR as wastewater AW. However, it is also possible to store a rinsing liquid S of a partial rinse cycle in a storage container (not shown) and to refill it into the rinsing chamber 7 in a later partial rinse cycle.

The dishwasher 1 the FIG. 1 comprises a water inlet device 13, which is provided for connection to the external water supply device WH. As in FIG. 1 For example, the external water supply device WH may be a faucet of a building-side water installation that provides pressurized inlet water ZW. The water inlet device 13 includes a fitting 14 which is provided for connection to the faucet WH. The connection can be made for example via a threaded arrangement, a bayonet arrangement or the like. Downstream of the connecting piece 14, a connection hose 15 is provided, which is preferably designed to be flexible. The downstream end of the connection tube 15 is connected to a housing-fixed connection piece 16.

Downstream of the housing-fixed connecting piece 16, a supply line 17 is provided, which is connected to an input side of a switchable by means of the control device 2 inlet valve 18. An output side of the inlet valve 18 in turn is connected to a liquid inlet 19 of the rinsing chamber 7. In this way, it is possible, by means of the water inlet device 13, to feed feed water ZW as dishwashing liquid S into the interior of the dishwashing chamber 7 of the dishwasher 1. The inlet valve 18 may be formed as a switchable solenoid valve, which has only an open position and a closed position. In the supply line 17, a water treatment system, not shown, for example, a water softening system may be provided.

Instead of or in addition to the device-side inlet valve 18 may also be provided between the connector 14 and the faucet WH an external inlet valve, in particular a so-called aqua-stop valve, which is preferably switchable by means of the control device, in particular shut-off and openable

Due to its weight force, the rinsing liquid S which has reached the rinsing chamber 7 via the liquid inlet 19 passes into a collection device 21 which is formed on a base 20 of the rinsing container 5 and which can preferably be designed as a collection pot 21. An input side of a circulation pump 22 is liquid-conducting connected to the collection pot 21. Furthermore, an output side of the circulation pump 22 is connected to a spraying device 23, 24, which makes it possible to apply the rinsing liquid S introduced into the rinsing chamber 7.

In the exemplary embodiment, the circulation pump 22 has a brushless AC motor, also called a BLAC motor. In principle, however, other engine concepts would also be conceivable.

In the embodiment of FIG. 1 the spraying device 23, 24 comprises an upper rotatable spraying arm 23 and a lower rotatable spraying arm 24. However, alternatively or additionally fixed spraying elements could be provided.

The flushing liquid S emerging from the spraying device 23, 24 when the circulating pump 22 is switched on is returned to the collecting pot 21 due to its weight within the flushing chamber 21. In order to be able to clean the flushing liquid S, in particular during a flushing of dirt particles, a screening system is provided in the region of the collecting pot 21 25 is provided, which is associated with an optical turbidity sensor 26. The turbidity sensor 26 can be used in particular for determining the degree of soiling of the rinsing liquid S, it being possible to adapt a rinse cycle to the determined degree of soiling. Likewise, the turbidity sensor 26 can be used to monitor the functionality of the screen system, which is explained in more detail below.

Furthermore, the dishwasher 1 in a conventional manner to a metering device 27, which makes it possible to offset the introduced into the washing chamber 7 rinsing liquid S with cleaning agents and / or cleaning aids to improve the cleaning effect and / or the drying effect of a rinse cycle.

Furthermore, in the FIG. 1 Dishwasher 1 shown on a drain pump 28, which serves to pump out no longer required rinsing liquid S from the washing chamber 7. The drain pump 28 has in the embodiment as well as the circulation pump 22, a brushless AC motor, also called BLAC motor, on. However, other engine concepts would also be conceivable here.

The inlet side of the drain pump 28 is connected to the collecting pot 21 and the outlet side of the drain pump 28 to a drain device 29. In this case, the drainage device 29 serves to discharge the pumped-out rinsing liquid S to the outside as wastewater AW.

The drainage device 29 comprises a connecting line 30 whose downstream end is connected to a housing-fixed connection 31 of the dishwasher 1. To an output of the housing-fixed terminal 31, a waste water hose 32 is attached, which is flexible. At the downstream end of the sewage hose 32, a fitting 33 is arranged, which is intended to connect the drainage device 29 with a sanitation AR. The sanitation AR may be a sewer pipe of a building-side water installation. The connection between the connecting piece 33 and the sewage pipe can be designed as a screw connection, as a bayonet connection, as a plug connection or the like.

FIG. 2 shows a block diagram of the household dishwasher 1 of FIG. 1 , wherein in particular the control and communication concept is shown. In the exemplary embodiment, a signal line 34 is provided, which connects the operating device 3 to the control device 2 such that operating commands of an operator can be transmitted from the operating device 3 to the control device 2. Furthermore, a signal line 35 is provided, which connects the control device 2 to the output device 4, so that information provided by the control device 2 can be transmitted to the output device 4 and output there to the operator.

Furthermore, a control line 36 is provided, which connects the control device 2 with the switchable inlet valve 18 such that the inlet valve 18 can be closed or opened by the control device 2. In this way, the filling of rinsing liquid S in the rinsing chamber 7 can be controlled by the control device 2.

A supply line 37 connects the control device 2 to the circulation pump 22. In this way, the circulation pump 22 can also be switched by the control device 2. The control device 2 is designed for switching on and off the circulation pump 22 and in particular for controlling and / or regulating the rotational speed of the circulation pump 22. Further, a supply line 38 is provided, which connects the control device 2 with the drain pump 28, so that the drain pump 28 by the control device 2 switchable, in particular off and on, is. The rotational speed of the drain pump 28 can also be controlled and / or regulated by the control device 2.

A signal line 39 furthermore connects the turbidity sensor 26 to the control device 2 so that its measured values can be transmitted to the control device 2 and can be used by the control device 2, in particular when a wash cycle is carried out to influence it.

FIG. 3 shows a detailed view of the dishwasher according to the invention the FIG. 1 , The collecting pot 21, which is let into the bottom 20 of the washing container, and the screening system 25 are shown in a sectional view.

The screen system 25 has a first fine screen 40, which is cylindrical, with its axis being upright. The underside of the cylindrical fine sieve 40 rests against the upper side of the bottom 41 of the collection pot 21. The cylindrical fine screen 40 extends to the top of the screen system 25th

In the bottom 41 of the collecting pot 21, a port 42 is provided, which is designed as a connecting piece 42 and connected via a hose or the like with the drain pump 28. The connecting piece 42 is arranged in a region of the bottom 41, which is covered by the Feinsiebzylinder 40. Outside this range, a further connection 43 is provided in the bottom 41, which is formed as a connecting piece 43 and connected via a hose, not shown, or a similar means with the circulation pump 22.

The fine screen 40 has passage openings 44 through which flushing liquid S can pass. The passage openings are dimensioned such that coarser dirt particles of the rinsing liquid S are retained. During a circulation operation, in which the circulation pump 22 of the dishwasher 1 is switched on, a recirculation flow US from rinsing liquid S arises, from which a first partial flow US1 exits from the interior of the cylindrical fine sieve 40 radially to the outside. In this way, at least part of the fine dirt contained in the rinsing liquid S is retained in the interior of the cylindrical fine sieve 40. Part of this dirt falls on the bottom 41 of the collecting pot 21, another part of this dirt adheres to the inside of the cylindrical fine screen 40. In order to be able to more thoroughly clean the rinsing liquid S, a micro-sieve 45 is provided, which is likewise of cylindrical design and is arranged concentrically around the fine sieve 40. Dirt contained in the first partial flow US1, which can pass through the fine sieve 40, is thereby deposited on the inside of the micro sieve cylinder 45, since its passage openings 46 are made smaller.

However, a possible removal of the dirt from the screen system 25 takes place in a pumping down phase, in which a pump-off stream AS is generated by switching on the drain pump 28 in order to pump out the flushing liquid S to the outside. A first partial flow AS1 of the pumped down flow AS is guided through the cylindrical microscreen 45 and through the cylindrical fine screen 40, the passage direction being opposite to the passage direction of the first partial flow US1 of the circulation flow US. As a result, adhering to the inside of the cylindrical micro sieve 45 and on the inside of the Feinsiebzylinders 40 dirt parts are solved and as well as those dirt particles which are located on the bottom 41 of the collecting pot 21, discharged by means of the Abpumpstromes AS to the outside.

The space enclosed by the fine screen cylinder 40 is also referred to as the collection chamber 47. The volume located outside the microscreen cylinder 45 in the collection pot 21 is further referred to as the circulation chamber 48. The circulation chamber 48 and the collecting chamber 47 are separated from one another by a sieve arrangement 40, 45 formed by the fine-screen cylinder 40 and the micro-sieve cylinder 45, through which the rinsing liquid S to be filtered can be flowed through. In this way, in the undisturbed operation of the dishwasher 1, an exchange of rinsing liquid S is possible, so that automatically adjusts a substantially identical level of rinsing liquid S in both chambers 47, 48. If, for example, rinsing liquid is removed from the circulation chamber 48 via the connection 43 of the circulation chamber 48 so that the level of rinsing liquid S in the circulation chamber 48 drops, rinsing liquid S flows from the collection chamber 47 through the sieve arrangement 40, 45 into the circulation chamber 48 by the weight force so that the levels in the recirculation chamber 48 and the collection chamber 47 equalize. Conversely, if, for example, rinsing liquid S via the terminal 42 of the Collection chamber 47 is removed from the collection chamber 47, then flushing liquid S flows from the circulation chamber 48 through the sieve assembly 40, 45 in the collection chamber 47. Such an arrangement of the circulation chamber 48 and the collection chamber 47, in which a compensation of the levels is due to the weight, is also called a communicating arrangement.

The circulation chamber 48 is directly connected via a further fine sieve 49, which is formed substantially flat, with the rinsing chamber 7 arranged above the sieve system 25. The flat fine sieve 49 makes it possible to penetrate the already mentioned first partial flow AS1 of the pumping flow AS into the collecting pot 21. The flat fine sieve 49 has such passage openings 50 that dirt is prevented from penetrating into the circulation chamber 48.

The flat fine sieve 49 further allows a second partial stream US2 of the circulating flow US to be guided directly from the rinsing chamber into the circulation chamber 48. Here, too, the penetration of dirt into the circulation chamber 48 is prevented. Due to the fact that only a first partial flow US1 of the circulating flow US is guided through the fine-screen cylinder 40 and the micro-sieve cylinder 45, a high circulating flow US can be generated, which has a favorable effect on the cleaning effect of the dishwasher 1.

In order to prevent objects from penetrating into the collecting chamber 47, which are not pumpable due to their size, a coarse screen 51 is provided, which has an upper section 52 and a lower section 53. The coarse filter 51 is formed as an upright cylinder. Whose upper portion 52 extends into the washing chamber 7 of the dishwasher 1, so that larger objects, which are washed from the side by flushing fluid S, are retained on the outside thereof. Articles falling directly from above into the inside of the coarse screen cylinder 51 are caught by ribs 54 overlapping in a plan view. Although they are then in the plenum 47, but are prevented by the structure of the coarse screen cylinder 51, with the first part of US1 circulation current US in the direction of Feinsiebs 40 and with a second partial flow AS2 of Abpumpstromes AS in the direction of the drain pump 28 move.

If the sieve arrangement 40, 45 formed by the fine-screen cylinder 40 and the micro-sieve cylinder 45 is now blocked, the first sub-stream US1 of the circulating stream US is interrupted or at least severely obstructed, just like the first sub-stream AS1 of the discharging stream AS. A sub-calculation of the first partial flow US1 of the circulation flow US leads to the fact that the rinsing liquid S is no longer sufficiently cleaned of micro-dirt, which can set an unsatisfactory rinsing result. Furthermore, an interruption of the first partial flow AS1 of the pumped-down flow AS results in that the flushing fluid S can no longer be completely discharged to the outside during an intended pump-down phase. Rather, in this case results in the screen system 25 by means of the reference numeral S 'designated distribution of the washing liquid S', in which after pumping a considerable amount of washing liquid S 'remains in the circulation chamber. This remaining amount of rinsing liquid S 'is usually dirty and further reduces the cleaning result of the rinse cycle just performed and / or subsequent rinsing.

In order to be able to detect a blockage of the sieve arrangement 40, 45, a detection sequence is provided in which the turbidity sensor 26 is used. The turbidity sensor 26 usually comprises a light source, for example a light-emitting diode, and a light receiver, for example a phototransistor, which are arranged such that the light emitted by the light-emitting diode is through the medium respectively located in the circulation chamber 48, ie as a rule flushing liquid S or air , hits the light receiver through. In this case, the turbidity sensor 26 is designed to determine the transmittance of the medium, that is, to determine the ratio of the intensity of the received light to the intensity of the emitted light, wherein the intensity is the power of the light per area.

In this case, an evaluation of a plurality of values of the turbidity level determined by means of the turbidity sensor 26 is provided, whereby it can be determined whether flushing liquid S 'is still in the circulation chamber 48 after pumping out the flushing liquid S, which is characteristic of a clogged screen arrangement 40, 45.

FIG. 4 shows a flowchart of a detection sequence for detecting a blockage in the region of the sieve system of the dishwasher according to the invention FIGS. 1 to 3 ,

The detection sequence ES according to the invention for detecting a blockage of the sieve arrangement 40, 45 can be carried out, for example, at the end of a water-carrying partial rinse cycle. In this case, after the start ST of the detection sequence ES at a circulation chamber 48 filled with flushing liquid S, a first measuring step MS1 is carried out in which a transmittance in the circulation chamber 48 is determined by means of the optical turbidity sensor 26.

Furthermore, within the scope of the recognition sequence ES, after the first measuring step MS1, a first pumping-down step AP1 for pumping out the flushing liquid S is provided via the connection 42 of the collecting chamber 47. If there is no blockage of the sieve arrangement 40, 45, the rinsing liquid S located in the circulation chamber 48 is thereby also pumped out, so that the circulation chamber 48 is essentially filled with air after the first pumping-off step AP1. However, if there is a blockage, at least part of this flushing liquid S remains in the circulation chamber 48.

Advantageously, the first pumping-down step AP1 comprises a load detection step LLP for detecting a power consumption of the drain pump 28, wherein, if the power consumption is greater than a threshold value provided for the drain pump 28, an abortion AB1 of the detection sequence takes place. An abort AB1 of the recognition sequence ES is understood to mean a termination thereof, in which a blockage of the sieve arrangement 40, 45 is considered excluded. If a suitably defined threshold value is exceeded, this indicates that, after the end of the pumping-down step AP1, flushing liquid S is still present in the collecting chamber 47. In this case, the rinsing liquid S present in the circulation chamber 48 before the first pumping-off step 48 can not run even if the sieve arrangement 40, 45 is continuous, so that if the recognition sequence ES is continued, an incorrect detection of a blockage would occur. This can be prevented by terminating AB1 of the recognition sequence ES.

In this case, after the cancellation AB1 of the detection sequence ES, an error treatment sequence FBS for the treatment of a malfunction of the drainage device 29 arranged downstream of the drain pump 28 can be provided. If, after the first pumping-off step AP1, flushing liquid S is still present in the collecting chamber 47, this is generally attributable to a malfunction of the drainage device 29 assigned to the drain pump. By now triggering a corresponding error handling sequence FBS, it is possible to prevent the malfunction from remaining unrecognized. In particular, the error handling sequence may include an output of a warning message via the output device 4 to an operator.

A load detection step LUP for detecting a power consumption of the circulation pump 22 is expediently provided after the first pumping down step AP1, wherein, if the power consumption is smaller than a threshold value provided for the circulation pump 22, an abort AB2 of the detection sequence ES takes place. A power consumption below a suitably fixed threshold is very likely to indicate that the circulation chamber 48 has been sufficiently emptied after the first pumping-down step AP1, in order to conclude that the filter arrangement is continuous. Abortment AB2 of the detection sequence simplifies the rinse cycle without affecting the detection reliability of blockages. If the specified threshold value is exceeded, although the level is too high or there is no blockage, then this is detected in the subsequent first evaluation step AW1, so that an error detection of a blockage is ruled out.

In this case, a first waiting step WS1 can be provided between the first pumping step AP1 and the load detection step LUP for detecting the power consumption of the circulation pump 22. In this way, an error detection of the power consumption of the circulation pump 22 due to transients can be prevented, which further improves the detection reliability.

If an abort AB2 of the detection sequence ES takes place in the load detection step for detecting the power consumption of the circulation pump 22, the power consumption of the circulation pump can be detected after the load detection step LUP 22, an adaptation step AN for redetermining the threshold provided for the circulation pump 22 may be provided, in which the power consumption of the circulation pump 22 is measured and a new threshold is determined from the measured power consumption. In this case, the measurement of the power consumption of the circulation pump 22 takes place when the circulation chamber is empty. In this way, a change in the power consumption of the circulating pump in dry running, so if it does not promote flushing, which is due to aging phenomena, be taken into account in a later implementation of the recognition sequence ES.

Advantageously, between the load detection step LUP for detecting the power consumption of the circulation pump 22 and the adaptation step AN, a second pumping step AP2 for pumping out the flushing liquid S via the connection 42 of the collection chamber 47 is provided. In this way, a falsification of the measurement of the power consumption of the circulation pump 22 in dry running is avoided by residual water, which improves the accuracy of the new threshold.

If, in the load detection step LLP for detecting a power consumption of the drain pump 28 and in the load detection step LUP for detecting the power consumption of the circulation pump 22, the conditions for executing the abort AB1 and AB2 are not met, after the first Abpumpschritt AP1 a second measuring step MS2 for renewed determination of Transmittance in the circulation chamber 48 by means of the optical turbidity sensor 26 performed. A now following first evaluation step AW1 for evaluating a change in the transmittance from the first measuring step MS1 to the second measuring step MS2 can now make a statement as to whether the rinsing liquid S was pumped out of the circulation chamber 48 in a sufficient manner by the first pumping-off step AP1, since the transmittance changes significantly when the metered medium of flushing liquid S transits to air. This in turn allows a statement as to whether the filter assembly is clogged or not.

In this case, the evaluation can take place in such a way that, if there is a decrease in the transmittance by at least a first minimum value, an abort AB3 of the recognition sequence ES is provided. The transmittance is clearer Rinse fluid about 30% higher than in air. Furthermore, depending on the degree of soiling, the degree of transmission in dirty washing liquid S is usually in a range between approximately 30% and 10% higher than in air. If there is now a decrease by a suitably set minimum value, it can be ruled out with great certainty that the decrease in the transmittance can be attributed to an additional and sudden contamination of the rinsing liquid S. Consequently, in this case, it is highly probable that a transition from washing liquid S to air has occurred during the first pumping step AP1, which ultimately means that the filter assembly 40, 45 is not clogged with great certainty. Error detection of blockages can be safely prevented. For example, the first minimum value may be a decrease of at least 10%.

After the first evaluation step AW1, an adaptation step AN for redetermining the threshold value provided for the circulation pump 22, in which the power consumption of the circulation pump 22 is measured and a new threshold value is measured, is advantageously provided if abort AB3 of the detection sequence ES occurs in the first evaluation step AW1 Power consumption is determined. In this case, the measurement of the power consumption of the circulating pump takes place with empty circulation chamber. In this way, a change in the power consumption of the circulation pump 22 in dry running, so if it does not promote flushing fluid S, which is caused by aging phenomena, be taken into account in a later implementation of the recognition sequence ES. The re-determination of the threshold value can be done by adding the measured power consumption and a safety value. It is also possible to multiply the measured power consumption with a safety factor.

Expediently, between the load detection step LUP for detecting the power consumption of the circulation pump 22 and the second measuring step MS2, a third pumping step AP3 is provided for pumping out the flushing liquid S via the connection 42 of the collection chamber 47. This avoids a falsification of the measurement of the transmittance in the second measuring step MS2 by residual water collecting during the load recognition step LUP, which causes the Accuracy of the detection of the transmittance and thus improves the detection reliability.

Equally advantageously, between the load detection step LUP for detecting the power consumption of the circulation pump 22 and the third Abpumpschritt AP3 a second waiting step WS2 be provided. In this way, in particular a falsification of the detection of the transmittance in the second measuring step MS2 by foaming in the load detection step LUP can be avoided, which further improves the detection reliability.

Advantageously, if the decrease in the transmittance determined in the first evaluation step AW1 is less than the first minimum value, after the second measuring step MS2 a rinsing liquid supplement SE is provided, in which the screening system 25 an additional amount of rinsing liquid S is fed, wherein after the rinsing liquid addition step SE third measuring step MS3 is provided for determining the transmittance in the circulation chamber 48 by means of the optical turbidity sensor 26, wherein a second evaluation step AW2 is provided for evaluating a change in the transmittance from the second measuring step MS2 to the third measuring step MS3, wherein if an increase in transmittance by at least a second minimum value is present, abort AB4 of the recognition sequence ES takes place.

If the decrease in the transmittance determined in the first evaluation step AW1 is less than the first minimum value, this may be due to the fact that either the rinsing liquid S has not drained from the circulation chamber 48 during the first and third pump-off steps, which constitutes a blockage of the sieve arrangement 40, 45 or that the rinsing liquid S was so heavily contaminated during the first measuring step MS1 that, due to its low transmittance, the first minimum value, ie the minimum decrease from the first measured transmittance to the second measured transmittance, despite a transition from rinsing liquid S to air What would be interpreted as a lack of constipation is not achieved.

In order to be able to differentiate between these two cases, the screening system 25 is supplied with an additional amount of purifying liquid S which is as clear as possible. For example can this be fed via the inlet valve 18 inlet water ZW. Now, a third measuring step MS3 for determining the transmittance is performed and its measured transmittance compared with the transmittance of the second measuring step MS2. If a minimum increase of, for example, 10% now results, it can now be concluded that no rinsing liquid was in the circulation chamber in the second measuring step MS2, which is a clear indication that the sieve arrangement 40, 45 is not blocked. In this case, abort AB4 of the recognition sequence may be provided.

Furthermore, if the increase in transmittance determined in the second evaluation step AW2 is less than the second minimum value, after the second evaluation step AW2, a fourth pumping step AP4 for pumping out the rinsing liquid S via the connection 42 of the collection chamber 47 can be provided, after the fourth pumping step AP4 a fourth measuring step MS4 for determining the transmittance in the circulation chamber 48 by means of the optical turbidity sensor 26 is provided, and wherein a third evaluation step AW3 is provided for evaluating a change in the transmittance from the third measuring step MS3 to the fourth measuring step MS4, wherein if a decrease in the transmittance at least a third minimum value is present, an abort AB5 of the recognition sequence ES takes place.

If the increase in transmittance determined in the second evaluation step AW2 is less than the second minimum value, this may be due to the fact that either the rinsing liquid S has not drained from the circulation chamber 48 during the first and third pumping steps, which is the blockage of the sieve arrangement 40, 45 or that the rinsing liquid supplied during the rinsing liquid supplementing step SE was so heavily polluted that due to its low transmittance, the second minimum value, ie the minimum increase from the second measured transmittance to the third measured transmittance, despite a transition from air to rinsing liquid S, what would be interpreted as a lack of constipation is not achieved. In order to be able to distinguish between these two cases, a fourth pumping step AP4 and a fourth measuring step MS4 are carried out to determine the transmittance. Thereupon the decrease from the third transmittance to the fourth transmittance is determined. This result can be derived from the result of the first evaluation step AW1, since at the beginning of the third measuring step MS1, due to the rinsing liquid supplementing step SE, clearing liquid S is generally clearer than in the first measuring step MS1 in the circulation chamber 48, so that the decrease in the degree of transmission during the transition from rinsing liquid to air is more pronounced. If, for example, a minimum decrease of, for example, 7% results, it can be concluded that no rinsing liquid S was located in the circulation chamber 48 in the fourth measuring step MS4, which is a clear indication that the sieve arrangement 40, 45 is not blocked. In this case, abort AB5 of the recognition sequence can be performed.

Advantageously, in the third evaluation step AW3, a decrease in the transmittance by less than the third minimum value is interpreted as blockage of the sieve arrangement 40, 45, so that the end EN of the recognition sequence is reached. In such a detection of a blockage of the sieve assembly 40, 45 an error detection is almost impossible. In this case, it is advantageous if an automatic sequence RW is provided for eliminating the blockage and / or issuing a warning message.

In one embodiment of the invention, the aquasensor 26 is calibrated to a first gradient before emptying the wash tub 20 in the medium water S with a first measuring step MS1. After a successful pumpdown process AP1 (empty detected by the drain pump 28), a gradient G2 is determined by a turbidity measurement in a second measuring step MS2.

Due to the different absorbance of the media water S and air (about 30%) can now be determined by comparing the two gradients, whether there is still water S in the outer region of the sump. This water could not be pumped out due to a soiled micro sieve.

• Abbruch des Spülprogramms und Anzeige "Sieb reinigen" (bzw. Wasserhahn LED)
• Spezielle Routine zur Reinigung des Siebes

As a result, the following measures could be taken:

• Cancellation of the washing program and display "Clean sieve" (or tap LED)
• Special routine for cleaning the sieve

LIST OF REFERENCE NUMBERS

1

dishwasher

2

control device

3

operating device

4

output device

5

rinse tank

6

door

7

rinsing chamber

8th

casing

9

upper dish rack

10

lower crockery basket

11

out rail

12

out rail

13

Water inlet device

14

connector

15

connecting hose

16

fixed housing

17

Supply, supply line

18

inlet valve

19

liquid inlet

20

Bottom of the washing container

21

Collection device, collection pot

22

circulating pump

23

upper spray arm

24

lower spray arm

25

screening system

26

turbidity sensor

27

metering

28

Drain pump

29

outflow device

30

connecting line

31

fixed housing

32

drain hose

33

connector

34

signal line

35

signal line

36

control line

37

supply line

38

supply line

39

signal line

40

cylindrical fine sieve

41

Bottom of the collection pot

42

Connection for drain pump

43

Connection for circulating pump

44

Passage openings of the cylindrical fine sieve

45

cylindrical microsieve

46

Passage openings of the cylindrical microsieve

47

plenum

48

circulation chamber

49

flat fine screen

50

Passage openings of the flat fine screen

51

coarse screen

52

upper section

53

lower section

54

ribs

WH

Water supply device, faucet

ZW

water supply

S

rinse

AR

Sanitation facility, sewer pipe

AW

sewage

IT

recognition sequence

ST

begin

MS1

first measuring step

AP1

first pumping step

LLP

Load detection step on the drain pump

AB1

cancellation

FBS

Error handling sequence

WS1

first waiting step

LUP

Load detection step on the circulation pump

STARTING AT 2

cancellation

AP2

second pumping step

ON

matching step

WS2

second waiting step

AP3

third pumping step

MS2

second measuring step

AW1

first evaluation step

FROM 3

cancellation

SE

Spülflüssigkeitsergänzungsschritt

MS3

third measuring step

AW2

second evaluation step

FROM 4

cancellation

AP4

fourth pumping step

MS4

fourth measuring step

AW3

third evaluation step

FROM 5

cancellation

EN

End of the recognition sequence

RW

Cleaning sequence and / or warning message

Claims (14)

1. Dishwasher, in particular a household dishwasher (1), having a control facility (2) configured for performing a wash cycle for cleaning items to be washed, having a screen system (25) for filtering a wash fluid (S), which has a circulation chamber (48) and a collection chamber (47), which communicates with the circulation chamber (48) by way of a screen arrangement (40, 45) through which the wash fluid (S) can flow, having a connector (43) disposed on the circulation chamber (48) for a circulation pump (22) for circulating the wash fluid (S) and having a connector (42) disposed on the collection chamber (47) for a drain pump (29) for evacuating the wash fluid (S),
   characterised in that the wash cycle comprises at least one detection sequence (ES) performed by the control facility (2) for detecting a blockage of the screen arrangement (40, 45), with a first measuring step (MS1) for determining a degree of transmission in the circulation chamber (48) filled with wash fluid (S) by means of an optical turbidity sensor (26) of the dishwasher being provided, with a first evacuation step (AP1) for evacuating the wash fluid (S) by way of the connector (42) of the collection chamber (47) being provided after the first measuring step (MS1), with a second measuring step (MS2) for determining the degree of transmission in the circulation chamber (48) by means of the optical turbidity sensor (26) being provided after the first evacuation step (AP1) and with a first evaluation step (AW1) for evaluating a change in the degree of transmission from the first measuring step (MS1) to the second measuring step (MS2) being provided ,wherein if there is a decrease in the degree of transmission of at least a first minimum value from the first measuring step (MS1) to the second measuring step (MS2), termination (AB1) of the detection sequence (ES) takes place and wherein termination of the detection sequence (ES) is understood as a cessation of the same, in which a blockage of the screen arrangement (40, 45) is considered to be excluded.
2. Dishwasher according to one of the preceding claims, characterised in that the first evacuation step (AP1) comprises a load detection step (LLP) for determining a power consumption of the drain pump (28), with termination of the detection sequence (ES) taking place, if the power consumption is greater than a threshold value provided for the drain pump (28).
3. Dishwasher according to the preceding claim, characterised in that, if termination of the detection sequence (ES) takes place during the load detection step (LLP) for determining the power consumption of the drain pump (29), an error processing sequence (FBS) for processing a malfunction of a discharge facility (29) disposed downstream of the drain pump (28) is provided.
4. Dishwasher according to one of the preceding claims, characterised in that a load detection step (LUP) for determining a power consumption of the circulation pump (22) is provided between the first evacuation step (AP1) and the second measuring step (MS2), with termination of the detection sequence (ES) taking place, if the power consumption is lower than a threshold value provided for the circulation pump (22).
5. Dishwasher according to the preceding claim, characterised in that a first waiting step (WS1) is provided between the first evacuation step (AP1) and the load detection step (LUP) for determining the power consumption of the circulation pump (22).
6. Dishwasher according to claim 4 or 5, characterised in that if termination of the detection sequence (ES) takes place during the load detection step (LUP) for determining the power consumption of the circulation pump (22), after the load detection step (LUP) for determining the power consumption of the circulation pump (22) an adjustment step (AN) is provided for redetermining the threshold value provided for the circulation pump (22), in which the power consumption of the circulation pump (22) is measured and a new threshold value is determined from the measured power consumption.
7. Dishwasher according to the preceding claim, characterised in that a second evacuation step (AP2) for evacuating the wash fluid (S) by way of the connector (42) of the collection chamber (47) is provided between the load detection step (LUP) for determining the power consumption of the circulation pump (22) and the adjustment step (AN).
8. Dishwasher according to one of claims 4 to 7, characterised in that a third evacuation step (AB3) for evacuating the wash fluid (S) by way of the connector (42) of the collection chamber (47) is provided between the load detection step (LUP) for determining the power consumption of the circulation pump (22) and the second measuring step (MS2).
9. Dishwasher according to the preceding claim, characterised in that a second waiting step (WS2) is provided between the load detection step (LUP) for determining the power consumption of the circulation pump (22) and the third evacuation step (AB3).
10. Dishwasher according to one of the preceding claims, characterised in that if the decrease in the degree of transmission determined in the first evaluation step (AW1) is lower than the first minimum value, after the second measuring step (MS2) a wash fluid supplementing step (SE) is provided, in which an additional quantity of wash fluid (S) is fed to the screen system (25), with a third measuring step (MS3) for determining the degree of transmission in the circulation chamber (48) by means of the optical turbidity sensor (26) being provided after the wash fluid supplementing step (SE), with a second evaluation step (AW2) for evaluating a change in the degree of transmission from the second measuring step (MS2) to the third measuring step (MS3) being provided, with termination of the detection sequence (ES) taking place, if an increase in the degree of transmission of at least a second minimum value is present.
11. Dishwasher according to one of the preceding claims, characterised in that if termination of the detection sequence (ES) takes place during the first evaluation step (AW1), after the first evaluation step (AW1), an adjustment step (AN) for redetermining the threshold value provided for the circulation pump (22) is provided, in which the power consumption of the circulation pump (22) is measured and a new threshold value is determined from the measured power consumption
12. Dishwasher according to claim 10 or 11, characterised in that if the increase in the degree of transmission determined in the second evaluation step (AW2) is lower than the second minimum value, after the second evaluation step (AW2) a fourth evacuation step (AP4) for evacuating the wash fluid (S) by way of the connector (42) of the collection chamber (47) is provided, with a fourth measuring step (MS4) for determining the degree of transmission in the circulation chamber (48) by means of the optical turbidity sensor (26) being provided after the fourth evacuation step (AP4) and with a third evaluation step (AW3) for evaluating a change in the degree of transmission from the third measuring step (MS3) to the fourth measuring step (MS4) being provided, with termination of the detection sequence (ES) taking place, if a decrease in the degree of transmission of at least a third minimum value is present.
13. Dishwasher according to the preceding claim, characterised in that in the third evaluation step (AW3) a decrease in the degree of transmission of less than the third minimum value is interpreted as a blockage of the screen arrangement (40, 45), with the control facility (2) initiating an automatic sequence (RW) for eliminating the blockage and/or outputting a warning message.
14. Method for operating a dishwasher (1), in particular according to one of the preceding claims, having a control facility (2) for performing a wash cycle for cleaning items to be washed, having a screen system (25) for filtering a wash fluid, which has a circulation chamber (48) and a collection chamber (47), which communicates with the circulation chamber (48) by way of a screen arrangement (40, 45) through which the wash fluid (S) can flow, having a connector (43) disposed on the circulation chamber (48) for a circulation pump (22) for circulating the wash fluid (S) and having a connector (42) disposed on the collection chamber (47) for a drain pump (28) for evacuating the wash fluid (S), characterised in that during the wash cycle the control facility (2) performs at least one detection sequence (ES) for detecting a blockage of the screen arrangement (40, 45), with a first measuring step (MS1) for determining a degree of transmission in the circulation chamber (48) filled with wash fluid (S) by means of an optical turbidity sensor (26) being provided, with a first evacuation step (AP1) for evacuating the wash fluid by way of the connector (42) of the collection chamber (47) being provided after the first measuring step (MS1), with a second measuring step (MS2) for determining the degree of transmission in the circulation chamber (48) by means of the optical turbidity sensor (26) being provided after the first evacuation step (AP1) and with a first evaluation step (AW1) for evaluating a change in the degree of transmission from the first measuring step (MS1) to the second measuring step (MS2) being provided, wherein if there is a decrease in the degree of transmission of at least a first minimum value from the first measuring step (MS1) to the second measuring step (MS2), termination (AB1) of the detection sequence (ES) takes place and wherein termination of the detection sequence (ES) is understood as a cessation of the same, in which a blockage of the screen arrangement (40, 45) is considered to be excluded.

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