Water-bearing household appliance and method for operating a water-bearing household appliance

Abstract

A water-carrying household appliance (1), in particular a dishwasher, with a wash chamber (4) for washing items that can be arranged in the wash chamber (4) by means of a wash liquor (16), a control device (20) for carrying out a wash program from a number of wash programs, a pump device (30) for pumping out the wash liquor (16) from the wash chamber (4), wherein pumping out means that the wash liquor (16) is conveyed from the wash chamber (4) into a wastewater pipe, a sensor (40) for outputting a sensor signal (41) depending on the presence of wash liquor (16) at the sensor (40), and a sieve arrangement (50) arranged between the sensor (40) and the pump device (30) for filtering the wash liquor (16), wherein the control device (20) is configured toto determine the degree of contamination of the sieve arrangement (50) as a function of a change in the pump output (31) of the pumping device (30) and a change in the sensor signal (41).

Description

[0001] The present invention relates to a water-bearing household appliance and a method for operating a water-bearing household appliance.

[0002] Conventional dishwashers have a drain pump designed to pump out the wash water after each stage of a wash cycle. This drain pump is protected by a filter screen, which prevents particles, such as food scraps, larger than a certain diameter from reaching the pump and causing blockages or damage. The particles are trapped by the screen. With an increasing number of wash cycles, this can lead to the screen becoming clogged, making it difficult or even impossible to pump out the wash water.

[0003] German patent application DE 10 2011 002 989 A1 describes a method for cleaning such a contaminated sieve. German patent application DE 10 2010 028 567 A1 describes a method for determining whether such a sieve is clogged.

[0004] From DE 102 46 017 A1 a method for detecting the condition of a filter device of a dishwasher is known, in which a predetermined quantity of washing liquid is set in a collection device of the dishwasher, the washing liquid is conveyed from the collection device through the filter device, a change over time in the quantity of washing liquid in the collection device is detected and a state of contamination of the filter device is assigned on the basis of the detected change over time in the quantity of washing liquid in the collection device.

[0005] Against this background, one object of the present invention is to propose an improved water-bearing household appliance.

[0006] According to a first aspect, a water-bearing household appliance, in particular a dishwasher, is proposed, comprising a wash chamber for washing items arranged in the wash chamber using a wash liquor, a control device for executing a wash program from a number of wash programs, a pump device for pumping the wash liquor out of the wash chamber, a sensor for outputting a sensor signal depending on the presence of wash liquor at the sensor, and a filter arrangement arranged between the sensor and the pump device for filtering the wash liquor. The control device is configured to determine the degree of contamination of the filter arrangement depending on a change in the pump output of the pump device and a change in the sensor signal.

[0007] Such a water-bearing household appliance offers the particular advantage that the degree of soiling of the filter assembly can be reliably and safely determined during a wash cycle. This contributes to the flawless operation of the appliance and increases operational reliability. Furthermore, measures suitable for cleaning a soiled or clogged filter assembly, such as removing and manually cleaning it, can be carried out in a targeted manner. This can reduce maintenance compared to regular, preventative measures, thereby lowering costs and increasing user-friendliness.

[0008] The wash liquor for rinsing the dishes consists primarily of water, which is supplied, for example, via a domestic water supply, and, depending on the current step of the wash cycle, one or more washing-active substances dissolved in the water, such as detergents and / or rinse aids. During a wash cycle, dirt, for example, detaches from the surface of the dishes and is absorbed by the wash liquor. This dirt includes both soluble substances, such as fats and short-chain molecules, as well as insoluble or very slowly soluble particles, which are also removed by the wash liquor.

[0009] The control device is configured to execute a wash program from a number of wash programs. A wash program comprises, for example, various sub-program steps, such as pre-rinsing, cleaning, and final rinsing. Each of the sub-program steps has, for example, a different sequence of control commands, such as heating, circulation, and draining, which the control device executes. The control device is preferably configured to control various other assemblies and / or components of the dishwasher according to the wash program to be executed. Other assemblies and / or components of the dishwasher include, for example, a circulation pump, a heating element, a valve, or the like. The control device can be implemented in hardware and / or software.In a hardware implementation, the control device can be, for example, a computer or a microprocessor. In a software implementation, the control device can be a computer program, a function, a routine, part of program code, or an executable object.

[0010] The pumping device is designed, for example, as a drain pump with a magnetic coupling. Pumping out means that the wash liquor is transferred from the wash chamber to a wastewater pipe. This occurs, for example, at the end of a pre-rinse, at the end of a cleaning cycle, and at the end of a final rinse. After pumping out, only a small residual amount of wash liquor remains in the wash chamber. Alternatively, partial pumping can be provided, in which a predetermined proportion, for example, 30%, or a predetermined volume, for example, 1 liter, of the wash liquor is pumped out.

[0011] The sensor for outputting the sensor signal is, for example, designed as an optical sensor with a transmitter and a receiver, where the path between the transmitter and receiver can be referred to as the measuring path. The optical sensor is configured, for example, to detect a transmission intensity across the measuring path, which depends on the medium through which the measuring path runs. The sensor is specifically arranged so that air or cleaning solution is present in the measuring path at different times during a cleaning process. The sensor signal can be an analog signal with a certain signal level or amplitude. However, the sensor signal can also be a binary signal or a bit sequence.In a simple case, the sensor signal is at least section by section directly proportional to the transmission over the measuring path, as is the case, for example, with a semiconductor photodiode as a receiver.

[0012] The sieve arrangement is specifically designed to filter the rinse water. For this purpose, the sieve arrangement includes, for example, one or more sieves. The individual sieves can be made of plastic, such as a thermoplastic, or of metal, particularly stainless steel. Each sieve can have uniformly arranged holes or meshes. The holes or meshes preferably have a uniform size. The holes or meshes can have different geometries, for example, round or rectangular, particularly square. The size of the holes or meshes is, for example, in the range of 0.1–5 mm in diameter or 0.1–5 mm in mesh size. The mesh size refers, for example, to the edge length of meshes with a square geometry. The filtering effect depends in particular on the size of the holes or the mesh size.The smaller the holes or meshes, the smaller the particles that are retained by the sieve.

[0013] Depending on various factors such as the soiling of the items being washed, the detergents used, the temperature of the wash water, and so on, the sieve assembly can become clogged with particles and / or dissolved dirt over time. For example, larger particles may block individual holes in a sieve. Furthermore, poorly soluble substances, such as fats, can accumulate on the sieve and gradually clog the holes or mesh of the sieve or sieve assembly.

[0014] The more holes or meshes are completely or partially blocked in this way, the less cleaning solution can pass through such a contaminated sieve per unit of time. In other words, the flow of cleaning solution through the sieve is reduced. The degree of contamination can be expressed, for example, as the degree of contamination. The degree of contamination can be determined, for instance, by measuring the liquid or water flow through the sieve. For this purpose, the water flow through the clean sieve is measured under predetermined conditions, such as a predetermined pressure differential across the sieve and the temperature of the cleaning solution. Subsequently, another flow measurement can be carried out at any time, particularly under the same predetermined conditions, and the flow rate can be determined as the quotient of the flow rate from the current measurement and the flow rate with a clean sieve.The degree of pollution can be calculated from this, for example as 1 - flow rate.

[0015] In this context, pump performance refers, for example, to the volume of flushing solution pumped per unit of time or the electrical power consumed by the pumping device. For instance, the pumping device might be an electromechanical pump with an impeller, which is driven at a specific, preferably constant, speed during pumping operation. In this case, the electrical power consumed, particularly the current required for operation, depends on the volume of flushing solution pumped. Therefore, the pumped volume can be determined from the electrical power consumed. This also allows us to identify when the pump is no longer pumping flushing solution.

[0016] The control device is configured to determine the degree of contamination of the filter assembly as a function of changes in the pump output and the sensor signal. "Determine" in this context means, for example, that the control device infers the degree of contamination from the changes in pump output and the sensor signal according to a mathematical relationship. This mathematical relationship could be, for example, one or more mathematical equations. The control device may also be configured to perform calculations. These calculations might include, for example, calculating variable values, such as the liquid flow rate per unit time, the degree of contamination, a time interval, or similar values, as a function of parameter values, such as the pump output, the sensor signal, one or more points in time, or similar values.Furthermore, it may be possible to iteratively optimize a system of linear or nonlinear equations. Additionally or alternatively, a lookup table may be provided from which the pollution degree values ​​can be read.

[0017] According to one embodiment of the water-bearing household appliance, the control device is designed to measure a time interval between the change in pump power and the change in the sensor signal and to determine the degree of contamination of the filter arrangement as a function of the measured time interval.

[0018] The degree of contamination of the sieve assembly can be determined particularly easily from the measured time period. This has the advantage that the control device can be designed simply, since no complex calculations are required to determine the degree of contamination.

[0019] For example, the sieve arrangement includes a vertically arranged sieve that separates a drain area, in which the pump is located, from a collection area, in which the sensor is located and which is designed to collect and / or gather the cleaning solution during operation of the water-using household appliance. Cleaning solution flows through the sieve from the collection area into the drain area. When the pump is activated, it first pumps the cleaning solution out of the drain area. As it is pumped out, the level in the drain area drops. This results in an increasing level difference between the cleaning solution in the drain area and the cleaning solution in the collection area, starting at the top of the vertical sieve. Due to this level difference, cleaning solution flows from the collection area through the sieve into the drain area.Depending on the pump's delivery capacity and the flow rate through the screen, a situation arises during a pumping process where the drain area is completely emptied by the pump, but additional flushing solution continues to flow through the screen from the collection area. If the screen is clean or only slightly soiled, the flushing solution flows in quickly, so this situation occurs only shortly before the end of the entire pumping process. However, if the screen is more heavily soiled, this situation can occur much earlier. If the pump is designed as described above, the occurrence of this situation can be detected by the current required by the pump, which drops sharply as soon as the pumped volume decreases. For example, the point at which this situation occurs is used as a trigger to start measuring the time interval.

[0020] For example, the sensor is positioned at a specific height relative to the sieve, such as halfway up. This means that, relative to the sieve's vertical length, the sensor is located in the center of the sieve. During the pumping process, the level of the flushing solution in the collection area will fall below the sensor's height. The sensor signal output will change significantly at this point because the medium at the sensor is no longer the flushing solution but air. This change in the sensor signal is used, for example, as a trigger to end the measurement period.

[0021] Depending on the specific geometry of the collection area, the discharge area, the screen, and the pumping capacity, the degree of screen contamination can be determined from the time interval. The longer the measured time interval, the higher the degree of screen contamination.

[0022] According to another embodiment of the water-bearing household appliance, the control device is designed to detect an electrical pump current for operating the pump device and to determine the pump power as a function of the detected electrical pump current.

[0023] According to another embodiment of the water-bearing household appliance, the control device is designed to detect a volume flow of the rinsing solution pumped by the pump device in order to determine the pump performance.

[0024] For example, a flow sensor can be provided to detect the volume flow.

[0025] According to another embodiment of the water-bearing household appliance, the sensor for detecting the presence of the rinsing liquid at the sensor includes an optical sensor.

[0026] According to another embodiment of the water-bearing household appliance, the optical sensor has an infrared emitter and an infrared receiver.

[0027] According to a further embodiment of the water-bearing household appliance, a pump housing is provided at the bottom of the wash chamber to collect the wash water flowing out of the wash chamber during operation and to house the pump device, the sensor, and the filter assembly. The pump device is arranged at an outlet of the pump housing and is configured to pump the wash water from the pump housing to the outlet. The filter assembly comprises a micro-filter that encloses a volume connected to the outlet, and the sensor is arranged laterally in the pump housing outside this volume.

[0028] The microsieve, which can also be called a fine sieve, is preferably made of plastic.

[0029] According to another embodiment of the water-bearing household appliance, the sieve arrangement comprises a cylindrical micro-sieve.

[0030] According to a further embodiment of the water-bearing household appliance, the sieve arrangement comprises a cylindrical coarse sieve arranged coaxially to the cylindrical micro sieve, with a larger or smaller diameter than the cylindrical micro sieve. The cylindrical coarse sieve is preferably made of metal, for example stainless steel or stainless-coated steel wire, and has a coarser sieve structure than the cylindrical micro sieve.

[0031] According to another embodiment of the water-bearing household appliance, the control device is set up to output the determined degree of pollution to a user interface device.

[0032] This embodiment has the advantage that a user of the water-bearing household appliance can be informed when the filter assembly is clogged or dirty and should be cleaned.

[0033] The user interface device includes, for example, a light-emitting diode (LED), a light bulb, a graphic display such as an LCD, an acoustic output unit, and / or a wireless communication interface such as Bluetooth or Wi-Fi. The wireless communication interface, in particular, offers the advantage that a user can be notified, for example, via software or an app on a portable mobile phone, especially a smartphone, and guided through the cleaning process, such as cleaning the sieve assembly. The app can be designed to guide the user through the cleaning process step by step.

[0034] According to another embodiment of the water-bearing household appliance, the control device is designed to carry out a screen cleaning program depending on the determined degree of soiling.

[0035] For example, the sieve assembly may be cleaned by blasting with rinsing solution and / or water at increased pressure. A special nozzle may be provided for this purpose in the area of ​​the sieve assembly. Furthermore, mechanical cleaning steps using brushes or similar equipment may also be provided.

[0036] This design has the advantage that the filter assembly is automatically cleaned. This can increase ease of use and operational reliability of the water-bearing household appliance.

[0037] According to a further embodiment of the water-bearing household appliance, at least one washing program from the number of washing programs includes several pumping operations, wherein the control device is configured to determine the degree of soiling during each pumping operation of the several pumping operations or only during predetermined pumping operations of the several pumping operations.

[0038] Selecting predetermined drain cycles can prevent the accidental triggering of cleaning measures. For example, after a pre-rinse, there may be a particularly high number of larger particles in the wash water, which are initially retained by the filter assembly and therefore partially block it. Determining the degree of soiling after the pre-rinse might thus suggest that cleaning measures are necessary. However, as the wash program progresses, the particles decompose or dissolve, for example, under the influence of various substances such as enzymes, allowing them to pass through the filter assembly and no longer block it. Determining the degree of soiling during a later drain cycle might therefore show that the filter assembly is not heavily soiled and no cleaning measures are required at that time.

[0039] According to a further embodiment of the water-bearing household appliance, the control device has a storage unit for storing a plurality of pollution levels determined during different pumping processes. The control device is configured to determine an average pollution level based on the plurality of pollution levels stored in the storage unit.

[0040] The control device can, for example, be configured to determine an average pollution level from a number of measured pollution levels. Furthermore, the control device can be configured to compare a currently measured pollution level with one or more previously measured pollution levels and, based on plausibility assumptions, determine whether the currently measured pollution level corresponds to an actual pollution level. This can help to identify erroneous measurements so that they can be disregarded during evaluation.

[0041] According to another embodiment of the water-bearing household appliance, the water-bearing household appliance is designed as a household dishwasher or as a washing machine.

[0042] According to a second aspect, a method for operating a water-bearing household appliance, in particular a dishwasher, is proposed. The water-bearing household appliance comprises a wash chamber for washing items arranged in the wash chamber using a wash liquor, a control device for executing a wash program from a number of wash programs, a pump device for pumping the wash liquor out of the wash chamber, a sensor for outputting a sensor signal depending on the presence of wash liquor at the sensor, and a filter arrangement arranged between the sensor and the pump device for filtering the wash liquor. In a first process step, the pump device is activated to pump out the wash liquor. In a second process step, the pump output of the pump device is measured as a function of time. In a third process step, the sensor signal is detected.In a fourth process step, the degree of contamination of the sieve arrangement is determined as a function of a change in the recorded pumping power of the pumping device and a change in the detected sensor signal of the sensor.

[0043] Controlling the pump device for pumping out the rinsing solution includes, in particular, applying electrical power to the pump device. Detecting the pump output as a function of time includes, for example, periodic measurement of the pump output or detection of a sudden change in pump output. Detecting the sensor signal includes, for example, measurement of the sensor signal as a function of time or detection of a sudden change in the sensor signal.

[0044] In embodiments of the method, instead of the pump power and / or the sensor signal, only times of change in the pump power and / or the sensor signal are recorded and / or detected.

[0045] Furthermore, a computer program product is proposed which, on a program-controlled device, initiates the execution of the procedure according to the second aspect.

[0046] A computer program product, such as a computer program tool, can be provided or delivered from a server on a network, for example, as a storage medium such as a memory card, USB stick, CD-ROM, DVD, or as a downloadable file. This can be done, for example, in a wireless communication network by transmitting the corresponding file containing the computer program product or tool.

[0047] The embodiments and features described for the proposed water-bearing household appliance apply accordingly to the proposed method.

[0048] Other possible implementations of the invention also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0049] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below with reference to preferred embodiments and the accompanying figures. Fig. Figure 1 shows a schematic perspective view of an embodiment of a water-bearing household appliance; Fig. Figure 2 shows a schematic representation of an embodiment of an arrangement of a pump device, a sensor and a sieve arrangement; Fig. Figure 3 shows a further schematic representation of the arrangement of the pump device, the sensor and the sieve arrangement of the Fig. 2; Fig. Figure 4 shows a further schematic representation of the arrangement of the pump device, the sensor and the sieve arrangement of the Fig. 2; Fig. Figure 5 shows a schematic diagram of the course of a pump output and a sensor signal; Fig. Figure 6 shows another schematic diagram of the course of a pump output and a sensor signal; and Fig. Figure 7 shows a block diagram of an embodiment of a method for operating a water-bearing household appliance.

[0050] In the figures, identical or functionally equivalent elements have been given the same reference symbols, unless otherwise indicated.

[0051] Fig. Figure 1 shows a schematic perspective view of an embodiment of a water-bearing household appliance 1. The water-bearing household appliance 1 is designed here as a household dishwasher 1. The household dishwasher 1 comprises a wash tub 2, which can be closed, in particular watertight, by a door 3. For this purpose, a sealing device (not shown) can be provided between the door 3 and the wash tub 2. The wash tub 2 is preferably cuboid in shape. The wash tub 2 can be arranged in a housing of the household dishwasher 1. The wash tub 2 and the door 3 can form a wash chamber 4 for washing dishes.

[0052] Door 3 is in the Fig. The door 3 is shown in its open position. It can be opened or closed by pivoting it about a pivot axis 5 located at its lower end. The door 3 can be used to open or close a loading opening 6 of the wash tank 2. The wash tank 2 has a base 7, a top 8 opposite the base 7, a rear wall 9 opposite the closed door 3, and two opposing side walls 10 and 11. The base 7, the top 8, the rear wall 9, and the side walls 10 and 11 can, for example, be made of stainless steel. Alternatively, the base 7 can, for example, be made of a plastic material.

[0053] The household dishwasher 1 further comprises at least one dishware holder 12, 13, 14. Preferably, several, for example three, dishware holders 12, 13, 14 can be provided, wherein the dishware holder 12 can be a lower dishware holder or a lower basket, the dishware holder 13 an upper dishware holder or an upper basket, and the dishware holder 14 a cutlery drawer. As the Fig. As further shown in Figure 1, the dishware holders 12, 13, 14 are arranged one above the other in the washing container 2. Each dishware holder 12 to 14 can be selectively moved into or out of the washing container 2. In particular, each dishware holder 12, 13, 14 can be pushed into the washing container 2 in an insertion direction E and pulled out of the washing container 2 in an extraction direction A opposite to the insertion direction E.

[0054] The household dishwasher 1 has a control device 20 arranged on the door 3. Furthermore, a pump device 30, which here is specifically designed as an electromechanical pump, is arranged on the floor 7 of the wash chamber 4. Next to the pump 30 is a sensor 40, which here is designed as an optical sensor 40 and is configured to detect the presence of wash liquid 16 (see figure). Fig. 2 - 4) at sensor 40 a sensor signal 41 (see Fig. 5, Fig. 6) to output. A sieve arrangement 50 is arranged between the sensor 40 and the pump 30. In the illustration of the Fig. 1. The sieve arrangement 50 separates the pump 30 from the rest of the washing chamber 4. This ensures, for example, that the washing liquid 16 can only reach the pump 30 through the sieve arrangement 50 and thus filtered.

[0055] Fig. Figure 2 shows a schematic representation of an embodiment of an arrangement of a pump device 30, a sensor 40 and a sieve arrangement 50 in a pump housing 60. The pump housing 60 is attached in particular to the bottom 7 of the wash chamber 4 of the household dishwasher 1. Fig. The washing liquid 16 is arranged in the pump housing 60. During operation of the water-bearing household appliance 1, the washing liquid 16 collects in the pump housing 60. The pump housing 60 has an outlet 61, which is connected to a wastewater pipe (not shown) and through which the washing liquid 16 can be conveyed as wastewater from the household dishwasher 1. The pump device 30 is arranged at the outlet 61 of the pump housing 60 so that it can pump the washing liquid 16 from the pump housing 60 into the wastewater pipe. Advantageously, the pump device 30 is thus located at the lowest point of the household dishwasher 1, which is also called the pump sump. Above the outlet 61 is a volume 51, which is separated from the rest of the pump housing 60 by the sieve arrangement 50, which here is designed as a cylindrical sieve. Washing liquid 16 must therefore pass through the sieve 50 to enter the volume 51.The sensor 40 is arranged laterally on the side of the pump housing 60, halfway up the height of the sieve 50 or the pump housing 60. The diagram shows the [missing information - likely a specific component or element] next to the pump housing 60. Fig. Figure 2 shows the control device 20, wherein the pump device 30 and the sensor 40 are connected to the control device 20. However, this illustration does not specify a spatial arrangement of the control device 20.

[0056] In the Fig. 2. The pump housing 60 is completely filled, meaning that volume 51 is also filled with rinsing solution 16. The following refers to the Fig. 3 and Fig. Four different situations that can occur when pumping out the rinsing liquid 16 through the pumping device 30 are explained.

[0057] Fig. Figure 3 shows the arrangement of the Fig. 2, where the pumping process is already underway and the pumping device 30 has essentially emptied the volume 51. The rinsing solution 16, which is located outside the volume 51 in the pump housing 60, flows through the sieve 50. The flow rate through the sieve 50 depends on the degree of soiling of the sieve 50. The situation shown only occurs when the sieve 50 is very heavily soiled, resulting in a very low flow rate. Therefore, the pump housing 60 is still almost completely full outside the volume 51 when the pumping device 30 has already emptied the volume 51.

[0058] The situation depicted corresponds to time tS of the Fig. 5 and Fig. 6, for which the control device 20, for example, detects that the pump device 30 is only delivering a small amount of rinse water 16 and starts a timer. The pump device 30, for example, continues to operate at a constant speed, so that any rinse water 16 that flows through the sieve 50 is immediately pumped out.

[0059] The rinse solution 16 gradually flows through the sieve 50 into volume 51 and thus to the pump device 30, where it is immediately pumped out. After a certain time, the level of the rinse solution 16 outside volume 51 drops to such an extent that the sensor 40 is free of rinse solution 16, as described in Fig. 4 is shown. At this time tE (see Fig. 5, Fig. 6) For example, the control device 20 detects a change in the sensor signal 41, whereupon it stops the timing. The control device 20 thus determines a time interval Δt, which results from the difference tE - tS. The larger the time interval Δt, the more heavily soiled the sieve 50 is, i.e., the higher the degree of soiling of the sieve 50.

[0060] Fig. Figure 5 shows a schematic diagram of the course of a pump output 31 and a sensor signal 41 over a time axis t, which, for example, occurs during the pumping out of flushing liquor 16, for example with an arrangement as shown in Figure 5. Fig. Figure 2 illustrates a scenario involving a sieve arrangement 50 with a low degree of contamination. At time t0, the pumping process begins, as indicated by a sudden increase in pump output 31. At time tS, the pump output 31 drops abruptly, indicating that the pump 30 is now delivering only a small amount of rinse water 16. At a later time tE, the sensor signal 41 changes abruptly, leading to the conclusion that the sensor 40 is now surrounded by air instead of rinse water 16. The difference between times tE and tS yields a time interval Δt, which can be used to determine the degree of contamination of the sieve arrangement 50.

[0061] Fig. Figure 6 shows another schematic diagram of the course of a pump output 31 and a sensor signal 41 over a time axis t. In contrast to the Fig. In case 5, the time interval Δt is significantly longer, which indicates a higher degree of contamination of the sieve arrangement 50.

[0062] Fig. Figure 7 shows a block diagram of an embodiment of a method for operating a water-bearing household appliance 1, for example the household dishwasher of the Fig. 1. In a first process step S1, the pump device 30 is activated to pump the wash liquor 16 out of the wash chamber 4. In a second process step S2, the pump output 31 is recorded as a function of time. This yields, for example, a diagram as shown in the Fig. 5 and Fig.Figure 6 shows the pump output 31. In a third process step S3, a change in the sensor signal 41 of sensor 40 is detected. Optionally, a time course of the sensor signal 41 can also be detected. In a fourth process step S4, a degree of contamination of the sieve arrangement 50 is determined as a function of a change in the measured pump output 31 and a change in the detected sensor signal 41.

[0063] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. In particular, a wide variety of embodiments of the pump device, the sensor, and / or the filter arrangement, as well as their spatial arrangement in a water-bearing household appliance, are conceivable. Furthermore, instead of a single sensor, a plurality of sensors can be used to determine more reliable values ​​for the degree of contamination. Reference symbols used: 1 water-bearing household appliance 2 washing containers 3 Door 4. Dishwashing area 5 swivel axes 6 Feed opening 7 Floor 8 ceiling 9 Back panel 10 side wall 11 Side wall 12 Dishwashing tray 13 Dishwashing tray 14 Dishwashing tray 16 rinsing liquid 20 Control device 30 Pump device 31 Pump capacity 40 Sensor 41 Sensor signal 50 sieve arrangement 51 volume 60 pump pot 61 Outlet A Pull-out direction E Insertion direction S1 Procedure step S2 process step S3 process step S4 Procedure step Δt time interval t0 time tS time tE time t time axis

Claims

[1] Water-carrying household appliance (1), in particular a dishwasher, with a wash chamber (4) for washing items that can be arranged in the wash chamber (4) by means of a wash liquor (16), a control device (20) for carrying out a wash program from a number of wash programs, a pump device (30) for pumping out the wash liquor (16) from the wash chamber (4), wherein pumping out means that the wash liquor (16) is conveyed from the wash chamber (4) into a wastewater pipe, a sensor (40) for outputting a sensor signal (41) depending on the presence of wash liquor (16) at the sensor (40), and a sieve arrangement (50) arranged between the sensor (40) and the pump device (30) for filtering the wash liquor (16), wherein the control device (20) is configured toto determine the degree of contamination of the sieve arrangement (50) as a function of a change in the pump output (31) of the pumping device (30) and a change in the sensor signal (41). [2] Water-bearing household appliance according to claim 1, characterized by , that the control device (20) is configured to measure a time interval (Δt) between the change in pump power (31) and the change in sensor signal (41) and to determine the degree of contamination of the sieve arrangement (50) as a function of the measured time interval (Δt). [3] Water-bearing household appliance according to claim 1 or 2, characterized by , that the control device (20) is configured to detect an electrical pump current for operating the pump device (30) and to determine the pump power (31) as a function of the detected electrical pump current. [4] Water-bearing household appliance according to one of claims 1-3, characterized by, that the control device (20) is configured to detect a volume flow of the flushing fluid (16) delivered by the pump device in order to determine the pump power (31). [5] Water-bearing household appliance according to one of claims 1-4, characterized by , that the sensor (40) for detecting the presence of the rinsing liquor (16) at the sensor (40) includes an optical sensor. [6] Water-bearing household appliance according to claim 5, characterized by that the optical sensor has an infrared emitter and an infrared receiver. [7] Water-bearing household appliance according to one of claims 1-6, characterized by, that a pump pot (60) is provided at the bottom of the wash chamber (4) for collecting the wash liquor (16) flowing out of the wash chamber (4) during operation of the water-bearing household appliance (1) and for receiving the pump device (30), the sensor (40) and the sieve arrangement (50), wherein the pump device (30) is arranged at an outlet (61) of the pump pot (60) and is configured to pump the wash liquor (16) from the pump pot (60) into the outlet (61), the sieve arrangement (50) comprises a micro-sieve which encloses a volume (51) connected with the outlet (61), and the sensor (40) is arranged laterally in the pump pot (60) outside the volume (51). [8] Water-bearing household appliance according to claim 7, characterized by , that the sieve arrangement (50) comprises a cylindrical microsieve. [9] Water-bearing household appliance according to one of claims 1-8, characterized by, that the control device (20) is configured to output the determined degree of pollution to a user interface device. [10] Water-bearing household appliance according to one of claims 1-9, characterized by , that the control device (20) is configured to perform a screen cleaning program depending on the determined degree of contamination. [11] Water-bearing household appliance according to one of claims 1-10, characterized by , that at least one rinsing program from the number of rinsing programs includes several pumping operations, wherein the control device (20) is configured to determine the degree of soiling at each pumping operation of the several pumping operations or only at predetermined pumping operations of the several pumping operations. [12] Water-bearing household appliance according to one of claims 1-11, characterized by, that the control device (20) has a storage unit for storing a plurality of pollution levels determined during different pumping operations, wherein the control device (20) is configured to determine an average pollution level depending on the plurality of pollution levels determined stored in the storage unit. [13] Water-bearing household appliance according to one of claims 1-12, characterized by , that the water-carrying household appliance (1) is designed as a household dishwasher or as a washing machine. [14] Method for operating a water-carrying household appliance (1), in particular a dishwasher, comprising a wash chamber (4) for washing items that can be arranged in the wash chamber (4) by means of a wash liquor (16), a control device (20) for carrying out a wash program from a number of wash programs, a pump device (30) for pumping out the wash liquor (16) from the wash chamber (4), wherein pumping out means that the wash liquor (16) is conveyed from the wash chamber (4) into a wastewater pipe, a sensor (40) for outputting a sensor signal (41) depending on the presence of wash liquor (16) at the sensor (40), and a sieve arrangement (50) arranged between the sensor (40) and the pump device (30) for filtering the wash liquor (16), comprising: Control (S1) of the pump device (30) for pumping out the rinsing solution (16), Recording (S2) a pump output (31) of the pumping device (30) as a function of time, Detecting (S3) the sensor signal (41) of the sensor (40), and Determining (S4) a degree of contamination of the sieve arrangement (50) as a function of a change in the detected pumping power (31) of the pumping device (30) and a change in the detected sensor signal (41). [15] Computer program product which causes the execution of the method according to claim 14 on a program-controlled device.

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