EP4196446A1

EP4196446A1 - Decalcifying water in a water-carrying domestic electrical appliance

Info

Publication number: EP4196446A1
Application number: EP21755367.6A
Authority: EP
Inventors: Uwe Has; Benjamin Wagner
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2020-08-12
Filing date: 2021-07-21
Publication date: 2023-06-21
Also published as: WO2022033817A1; DE102020210205A1; CN116113601A

Abstract

The invention relates to a water-carrying domestic electrical appliance (1), comprising at least one water filter (2, 2a-2e) in the form of an intercalation filter with at least one intercalation volume (7, 7a, 7b), wherein the intercalation volume (7, 7a, 7b) is designed to store interfering ions from water to be decalcified (N), and water running through the intercalation filter (2, 2a-2e) can be drawn as service water (N) for operating at least one water-carrying functional unit of the domestic electrical appliance (1). In a method for operating a water-carrying domestic electrical appliance (1), decalcified service water (N) is generated by storing interfering ions in an intercalation volume (7, 7a) of an intercalation filter (2, 2a-3d) of the domestic electrical appliance (1). The invention can be particularly advantageously applied to cooking appliances, especially with a steam treatment function, laundry appliances and dishwashers.

Description

Descaling water in a water-carrying electrical household appliance

The invention relates to a water-carrying electrical household appliance, having a water filter with a filter volume, the filter volume being set up to filter out interfering ions from water to be decalcified, and water that has passed through the filter can be removed as process water for operating at least one water-carrying functional unit of the electrical household appliance. The invention also relates to a method for operating a water-bearing electrical household appliance in which decalcified service water is produced. The invention can be applied particularly advantageously to cooking appliances, in particular with a steam treatment function, laundry care appliances and rinsing appliances.

Many electrically operated household appliances ("household appliances") require water to operate or to provide certain functions. This water can be made available to a household appliance (a) manually (e.g. by manually filling a water tank), refilling being requested by a signal if the water tank is empty. This is often the case with cheaper steamers (e.g. ovens with a steamer function), coffee machines, etc. As an alternative or in addition, the water can be made available to the household appliance automatically, for example through a fresh water connection, from which the household appliance draws off the required amount of water when required. This is usually the case, for example, with washing machines, dishwashers, expensive steamers, etc.

In any case, the quality of the water used by the household appliance should be so "good" that the household appliance is not damaged by the water drawn off. The definition of "good water quality" usually corresponds to a sufficiently low lime content in the water, which is also referred to as "water hardness", so that limescale deposits in the device (e.g. on radiators, in or on pipes) or on treated goods (e.g. on food, cutlery, glasses, accessories, etc.) should be avoided as far as possible. The lime deposits are typically formed by means of hardness components such as calcium, magnesium, carbonates and possibly traces of various other substances such as strontium, barium, etc. or their ions. To simplify the description such water-soluble hardness components are summarized below under the term "contaminants".

In order to prevent limescale formation, it has hitherto been known to decalcify the water before it is heated, in particular before it is evaporated. So far, descaling can be achieved, for example, by:

1) ion exchangers, which in turn have to be regenerated by regularly adding salt. Salt regeneration requires expensive equipment components. In addition, the salt is drained from the device with sewage, which is harmful to sewage treatment plants.

2) Chemical decalcification, in which chemicals are added to the water that suppress or dissolve limescale formation. However, these chemicals should not get on or into food, for example. Furthermore, these chemicals are also harmful to sewage treatment plants.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art and in particular to provide a user-friendly option that is easy to set up and produce soft or low-impurity water in a water-conducting electrical household appliance in a particularly environmentally friendly manner.

This object is solved according to the features of the independent claims. Advantageous embodiments are the subject matter of the dependent claims, the description and the drawings.

The object is achieved by a water-carrying electrical household appliance having at least one water filter in the form of an intercalation filter with at least one intercalation volume, the intercalation volume being set up to store ions of impurities dissolved in water (also referred to below as “interference ions”) from the water to be decalcified , and the water that has flowed through or has passed through the intercalation filter can be removed for operating the household electrical appliance. The intercalation volume does not require any additional chemicals to bind interfering ions, since the interfering ions are bound by intercalation in chemical compounds ("intercalation compounds"), with the chemical compounds not significantly changing their structure during the intercalation process. Filtering by intercalation is therefore particularly environmentally friendly and user-friendly. In addition, an intercalation filter can be implemented particularly easily. The necessary cleaning effort is also significantly reduced, since the service life of the intercalation volume is around a factor of two to five longer than that of filters in conventional decalcifying systems. This in turn massively reduces the consumption of descaling agent. Ideally, no more descaling agents are needed over the lifetime of the appliance (steamer).

An “intercalation volume” is understood to mean, in particular, a substance volume that consists entirely or partially of intercalation material, possibly of intercalation material with a support structure. The intercalation material can have one or more intercalation compounds.

The water that has passed through the intercalation filter can have at least partially interacted with at least one intercalation volume, i.e. the water has flowed through the intercalation volume and/or flowed past it, so that at least some of the interfering ions dissolved in the water could be stored in the intercalation material. This removal of interfering ions from the water reduces its hardness. Water that has been softened or decalcified in this way can be used as process water by the electrical household appliance.

Which interference ions are stored in the intercalation volume depends on the at least one intercalation compound present therein, which can be present, for example, as a so-called "host lattice". The at least one intercalation compound can include, for example, quasi-metallic layers in graphite or in the transition metal sulfides NbS2 or TaS2, semiconductive systems such as TiS2 and SnS2 and nonconductive compounds such as clay minerals (e.g. kaolinite). It has turned out to be particularly advantageous for use for water decalcification if the intercalation compound has or consists of FeMn(CN)e or MnFe(CN)e. The interfering ions can include, in particular, ions of limescale or hardeners such as Ca ²⁺ , Mg ²⁺ and their carbonates, etc., dissolved in water. The intercalation volume can be designed in particular to store positively charged interfering ions (cations). This is advantageous because ions of hardness constituents, which are often present as cations, dissolved in water can then be removed particularly effectively from the water to be decalcified by storage in the intercalation volume.

The water-carrying electrical household appliance can be a household appliance in the sense of white goods. It can be a large household appliance (e.g. a cooking appliance such as a steamer and an oven with steamer functionality, a laundry treatment appliance such as a washing machine and washer-dryer, a dishwasher, etc.) or a small household appliance (e.g. a coffee machine, a kettle, an iron, etc.). The at least one water-carrying functional unit can be, for example, an evaporator for generating steam for steaming food to be cooked, a water heater for rinsing water, washing water or liquor, for making coffee or tea, etc.

The intercalation filter can have one or more intercalation volumes.

In one configuration, the intercalation filter has at least one filter housing with a service water chamber and a process water chamber, the two chambers are separated from one another in a manner that is practically impermeable to water, the two chambers are separated from one another so that they are permeable to interference ions of at least a first polarity, and the service water chamber has at least one intercalation volume is assigned, which is set up to store interfering ions of a second polarity.

This configuration has the advantage that second polarity interfering ions are removed from the water to be decalcified that is filled into the service water chamber by intercalation into the intercalation volume, while first polarity interfering ions can get from the service water chamber into the process chamber, eg by diffusion. The resulting "filtered" water can be removed as process water for operating the electrical household appliance from the process water chamber. The fact that the two chambers are separated from one another "practically" impermeable to water can include that they are separated from one another in a watertight manner or that only so little water can flow from one chamber into the other chamber that the function of the intercalation filter is not noticeably impaired. In the latter case, the two chambers can be separated from one another, for example by a dividing wall which has a high flow resistance to water. The fact that the two chambers are separated so that they are permeable to interference ions of at least one first polarity means that they can also be separated so that they are permeable to interference ions of both polarities, ie both anions and cations can be exchanged between the chambers.

The fact that at least one intercalation volume is “assigned” to the service water chamber means that water located in the service water chamber can interact with the at least one intercalation volume. This can be implemented, for example, in such a way that at least one intercalation volume is accommodated in the service water chamber and/or at least one intercalation volume delimits the service water chamber or serves as a wall of the service water chamber. The latter case can occur, for example, when an intercalation volume is used as a partition between the process water chamber and the process wall chamber.

It is a development that the first polarity is an electrically negative polarity and the second polarity is an electrically positive polarity. Interference ions of the first polarity then correspond to anions, and interference ions of the second polarity to cations. Correspondingly, cations can be intercalated in the intercalation volume and anions can be exchanged between the chambers. It is an alternative embodiment that the first polarity is an electrically positive polarity and the second polarity is an electrically negative polarity. Interference ions of the first polarity then correspond to cations, and interference ions of the second polarity to anions. Correspondingly, anions can be intercalated in the intercalation volume and cations can be exchanged between the chambers.

In one configuration, at least a first electrode of a pair of electrodes is accommodated in the process water chamber and at least a second electrode of the pair of electrodes is accommodated in the process water chamber. This has the advantage that a movement of the interfering ions in the intercalation filter can be prevented by applying a voltage difference to the pair of electrodes can be influenced in a targeted manner, e.g. to move interfering ions into an intercalation volume for more effective decalcification, to move interfering ions from the service water chamber into the process water chamber and/or to counteract an osmotic pressure between the two chambers.

In one development, the first electrode can be operated with the first polarity, while the second electrode can be operated with the second polarity. Alternatively, the first electrode may be operable with the second polarity while the second electrode is operable with the first polarity. If an electrode is operated with an electrically positive polarity, it can also be referred to as a positive pole, otherwise as a negative pole. For example, if the first electrode located in the process water chamber is operated as a negative pole and the second electrode located in the process water chamber is operated as a positive pole, anions are shifted from the process water chamber to the process water chamber. For example, cations can be stored in the intercalation volume.

This configuration is also advantageous because by reversing the polarity of the electrodes during a cleaning phase, the interfering ions embedded in the intercalation volume can be at least partially removed again, as a result of which particularly simple automatic cleaning of the intercalation filter can be achieved.

In one configuration, a voltage applied between the two electrodes of the pair of electrodes is approximately 1 V, in particular less than 1.23 V. In this way, the advantage is achieved that electrolysis of the water and thus hydrogen formation is reliably prevented in practice.

In one development, at least one electrode is produced as a component that is separate from an intercalation volume. This advantageously enables a particularly simple manufacture.

In one configuration, at least one of the two electrodes consists at least partially of electrically conductive intercalation material ("intercalation electrode"). This results in the advantage that components can be saved and also a structure that is particularly effective for filtering out interference ions. In particular, in a chamber in which such an intercalation electrode is located, a separate, not electrically connected intercalation volume can be dispensed with. Intercalation material suitable for this purpose can contain, for example, 60% to 70% carbon, for example graphite intercalation compounds. Intercalation electrodes, which consist almost entirely of electrically conductive intercalation material, can have, for example, metallic connection lugs or the like, via which they are connected to a voltage source.

It is also possible to embed metallic electrode material in intercalation material, e.g. to homogenize an electric field distribution in a flat electrode.

The electrodes can be designed, for example, as—in particular flat or flat—meshes or mats or as “tissue balls”. Metallic electrodes or electrode areas can be in the form of metal foils, sheets or plates perforated in the manner of a sieve. The electrodes can be surface treated, e.g. coated, for a particularly long service life. In a further development, when a voltage difference is applied to the electrodes of a pair of electrodes, an electric field similar to an electric field generated between capacitor plates is generated between them.

In a further development, the at least one intercalation volume is arranged in a non-crossing arrangement between a water inlet and a water outlet of the process water chamber and/or the process water chamber. Water running through one or both of these chambers does not need to flow through an intercalation volume - e.g. arranged transversely to the direction of flow. This configuration has the advantage that a high volume flow of water can be maintained through the at least one chamber, since there is no flow obstacle in the form of an intercalation volume between the water inlet and the water outlet. The incorporation of the interfering ions of the process water in the intercalation volume - e.g. arranged next to the main flow path of the process water - can be designed particularly effectively, for example, in that the interfering ions are moved by the electric field applied between the electrodes of the pair of electrodes in the direction of the intercalation volume, where they are stored can become.

It is a further development that the at least one intercalation volume is arranged in a crossing arrangement between a water inlet and a water outlet of the service water chamber and / or the process water chamber is arranged. Water flowing through one or both of these chambers then flows through the intercalation volume arranged transverse to the direction of flow. This configuration has the advantage that electrodes can also be dispensed with. The intercalation volume is then advantageously water-permeable, in particular designed to be highly water-permeable.

In one embodiment, the service water chamber is separated from the process water chamber by a separating layer or separating wall, which has at least one intercalation volume or consists of intercalation volumes. This enables a particularly compact design of the intercalation filter. Such a separating layer can only be slightly permeable to water, since it has a high flow resistance, for example when it is designed as a dense fabric made of intercalation material (having one or more intercalation compounds).

In one embodiment, the process water chamber is separated from the process water chamber by a membrane that is impermeable to water and permeable at least to the interfering ions of the first polarity (which in particular itself has no intercalation material) and the intercalation volume is accommodated at least in the process water chamber. This effectively prevents water from mixing between the service water chamber and the process water chamber, which can increase decalcification effectiveness and service water yield. The membrane layer can be impermeable to interfering ions of the second polarity, which advantageously prevents these interfering ions from diffusing from the process water chamber into the service water chamber. The membrane can be referred to as an ion exchange membrane. In such a configuration, the intercalation volume is advantageously designed to be water-permeable in order to provide a large surface area for the incorporation of interfering ions and thereby increase the softening effectiveness.

In one configuration, at least one intercalation volume is accommodated in the process water chamber. This has the advantage that interfering ions can also be removed from the process water by being stored in an intercalation volume. This in turn results in the advantage that a diffusion pressure built up by the difference in concentration of these interfering ions between the two chambers is reduced, so that descaling effectiveness can be increased. The advantage is also achieved in this way that Process water is better suited for possible mixing with service water at the beginning of a softening process, since it then has fewer positively charged interfering ions than fresh water.

It is a further development that the intercalation material located in the service water chamber corresponds to an intercalation material in the process water chamber. It is a further development that the intercalation material in the service water chamber differs from the intercalation material in the process water chamber, e.g. with regard to the type of interfering ions stored.

In general, the type and number of the intercalation material or the intercalation compound that can have an intercalation volume is not limited. An intercalation volume can also have several different intercalation materials which, for example, store interfering ions of different polarity, different interfering ions of the same polarity, etc.

In one embodiment, the service water chamber or a water outlet thereof can be connected to a service water tank from which the service water for operating the electrical household appliance can be removed. In this way, the advantage is achieved that service water that is not required immediately can be stored in order to be used later. The descaling process can also be carried out as an independent process. The tank can also be referred to as a reservoir.

In one embodiment, the process water chamber or a water outlet thereof can be connected to a process water tank that can be emptied—automatically or on the user side. This advantageously simplifies draining of the process water if it is not routed directly into a drain. The advantage is also achieved in this way that a concentration of interfering ions in the process water increases more slowly than without a process water tank. The process water tank can advantageously be removed by a user when it is emptied on the useful side.

In general, water can be passed through the service water chamber and/or through the process water chamber in a continuous flow or in a circuit. In a run-through operation, water is only passed through the associated chamber once, and then for the case of the process water, drained or, in the case of the service water, delivered to the water-using entity and/or stored in the service water tank. In the circuit, on the other hand, the water is circulated several times in succession through the associated chamber. The transport of the water can be made possible by appropriate pumps.

It is a further development that water is passed through the service water chamber, which enables a particularly high volume of decalcified water to be produced.

In one embodiment, the process water is circulated through the process water chamber, which enables the process water to be decalcified to a particularly high degree. The circuit can include, for example, the service water chamber and, if present, the service water tank.

It is a further development that the process water can be routed through the process water chamber either in a continuous flow or in a circuit. For this purpose, for example, corresponding valves, e.g. shut-off valves, can be provided which can be switched accordingly, e.g. blocking/conducting, in particular by a control device of the household appliance.

In one embodiment, the process water is conducted through the process water chamber. This has the advantage that the concentration of interfering ions in the process water chamber remains low compared to circulation operation, which means that a larger quantity of interfering ions in the first charge can get from the service water chamber into the process water chamber, since diffusion resistance is comparatively low.

In one embodiment, the process water is guided through the process water chamber in a circulating manner, which advantageously greatly reduces the amount of process water required to operate the intercalation filter compared to continuous operation. The circuit can include, for example, the process water chamber and, if present, the process water tank. In one embodiment, it is monitored when the concentration of interfering ions in the process water reaches or exceeds at least a predetermined level, and at least one action to replace the process water is triggered in this case. This has the advantage that a sufficient transfer of interfering ions from the service water chamber into the process water chamber can be maintained for effective decalcification, which would otherwise only be low if the concentration of interfering ions in the process water was too high due to the diffusion pressure counteracting the electric field. The at least one action can include, for example, automatically draining the process water and/or issuing a message to a user to drain the process water.

In a further development, the monitoring can be carried out independently by a user. In this way he can automatically trigger or carry out the draining of the process water if he has the impression that draining is necessary.

It is an embodiment that the electrical household appliance is set up to automatically monitor when the concentration of interfering ions in the process water reaches or exceeds at least a predetermined level and then at least one action to replace the process water is triggered. This enables a particularly reliable monitoring of a suitable replacement of the process water.

If the device has a permanent waste water connection to the house drainage system, draining can take place automatically. This draining takes place particularly advantageously at night, so that any use of the device is not impeded. If there is no permanent waste water connection, the user must dispose of the process water manually, e.g. by removing and emptying removable water tanks.

The point in time when the concentration of the interfering ions in the process water reaches or exceeds at least a predetermined level (e.g. at least one threshold or limit value) can be indirectly detected with automatic monitoring, for example, by the fact that the useful life of the intercalation filter reaches or exceeds a predetermined threshold value and/or that an amount of process water that has passed through the intercalation filter or the process water chamber reaches or exceeds a predetermined threshold value.

For this purpose, for example, the hardness of externally supplied water, the process water currently running through or circulating and/or the process water currently running through or circulating can be used. In addition, other parameters such as salinity, oxygen content, water temperature, etc. can be taken into account. These influencing variables can, for example, be determined using known values at the installation site of the electrical household appliance (e.g. using a known regional water hardness) and/or measured on the appliance side.

It is advantageous if the water hardness (e.g. an average degree of hardness) of the water added to the household appliance (e.g. fresh or drinking water) is known to the household appliance. This is because the level can be adjusted to the water hardness in order to obtain a particularly advantageous point in time for draining the process water.

Alternatively, the point in time can be determined by means of a sensor or a sensor system which measures a concentration of interfering ions in the service water and/or in the process water. From this, a particularly advantageous point in time for draining/replacing the process water can be determined for the local usage situation. A further advantage is that a possible malfunction or aging or fatigue of the intercalation filter can then be detected.

In one configuration, the household electrical appliance is set up to monitor the concentration of the interfering ions in the process water using cyclic voltammetry. The principle of cyclic voltammetry, which is known in principle, is briefly explained below: in cyclic voltammetry, the differences in the atomic masses of the interfering ions are used. The atomic mass of calcium is around 40, the atomic mass of magnesium around 24.3 and the relevant masses of carbonates (depending on the type of carbonate considered) are considerably higher. When ions in a liquid move along the field upon application of an electric field, this directional movement corresponds to an electric current. When measuring this current with an ammeter, only the total electric current can be measured. However, the movement of the individual charge carriers contributes very differently to this current at. When an ion moves through water under the influence of the electric field, its speed of movement depends on its charge (the higher the charge, the faster) and its mobility (the more mobile, the faster). The mobility of the ion, in turn, depends on its size (the larger, the slower, because larger atoms are more likely to be hindered in their movement by other atoms or by the molecules in the water) and its mass (the heavier, the slower, because heavy atoms are significantly slower react to acceleration). These circumstances are used in cyclic voltammetry, in which an--advantageously continuously--increasing voltage is applied to a measurement volume. Charge carriers (ions) dissolved in water will move faster and earlier if they are very highly charged, very small and very light. A stepped current curve will therefore set in with a continuously increasing voltage. From the expression of these current levels, it can be automatically estimated which charge carriers are in the water (identification of impurities) and how many charge carriers are in the water (estimation of the concentration). The necessary measurement voltages are typically in the range between about 1 volt and 2 volts.

In addition to draining the process water, one or more cleaning and/or service procedures can be carried out, e.g. flushing the chambers, reversing the electrode polarity in order to trigger intercalation volumes embedded interference ions, adding decalcification agent, replacing at least one intercalation volume, etc.

The object is also achieved by a method for operating a water-carrying electrical household appliance in which decalcified service water is produced by interfering ions being stored in an intercalation volume of an intercalation filter of the electrical household appliance. The method can be designed analogously to the electrical household appliance and has the same advantages.

The characteristics, features and advantages of this invention described above, and the manner in which they are achieved, will become clearer and more clearly understood in connection with the following schematic description of an exemplary embodiment, which will be explained in more detail in connection with the drawings. 1 shows a sketch of a water-carrying electrical household appliance in the area of its intercalation filter;

2 shows a more detailed sketch of an intercalation filter according to a first embodiment;

3 shows a more detailed sketch of an intercalation filter according to a second embodiment;

4 shows a more detailed sketch of an intercalation filter according to a third embodiment;

5 shows a more detailed sketch of an intercalation filter according to a fourth exemplary embodiment and

FIG. 6 shows a more detailed sketch of an intercalation filter according to a fifth exemplary embodiment.

Fig. 1 shows an outline of a water-bearing electrical household appliance 1, e.g. an oven with a steam treatment function. The household electrical appliance 1 has an intercalation filter 2, which serves to reduce a quantity of disruptive ions in the water W to be used by the household electrical appliance, e.g. to slow down calcification.

The intercalation filter 2 has at least one filter housing 3 with a service water chamber 4 and a process water chamber 5 . Water W taken from the service water chamber 4 is ion-reduced, while water W taken from the process water chamber 5 has an increased proportion of ions and is intended in particular for disposal.

The two chambers 4 and 5 are separated from one another so that they are impermeable to water and permeable to ions of a first polarity (here, for example, to negatively charged anions). For this purpose, a corresponding partition 6 is drawn in, which at the same time serves as an intercalation volume 7 and which is set up to store interfering ions of a second polarity (cations). Since the dividing wall 6 adjoins the service water chamber 4 and cations located in the service water chamber 4 can therefore be stored in the intercalation volume 7, the intercalation volume 7 is “assigned” to the service water chamber 4. At least one first electrode 8 of a pair of electrodes 8, 9 is accommodated in the service water chamber 4, which can be operated, for example, as an electrical positive pole, and at least one second electrode 9 of the pair of electrodes 8, 9 is accommodated in the process water chamber 5, which can be operated, for example, as an electrical negative pole is. When a voltage difference is applied to the electrodes 8, 9, cations in the process water chamber 4 are increasingly moved into or through the intercalation volume 7 and are at least partially bound in the intercalation volume 7. Since the water hardness is essentially determined by the presence of dissolved alkaline earth cations (eg Ca ²⁺ , Mg ²⁺ , etc.), the water hardness in the service water chamber 4 is reduced by this forced movement of the cations through the intercalation volume 7 .

For filling and/or refilling the two chambers 4, 5 there is a fresh water supply line 10 which can be connected to a water line or a water tank (not shown). The fresh water supply line 10 has a particle filter 11 and a shut-off valve 12 . The particle filter 11 is used, for example, to filter dust, sand, lint, deposits, etc.

The household electrical appliance 1 also has a shut-off valve 13 which is fluidically connected to the shut-off valve 12 on the one hand and to a shut-off valve 15 via a particle filter 14 on the other hand. On the other hand, the shut-off valve 15 is connected to a water inlet of the service water chamber 4 . There is also a shut-off valve 16 which is fluidically connected to the shut-off valve 12 on the one hand and to a shut-off valve 18 via a particle filter 17 on the other hand. On the other hand, the shut-off valve 18 is connected to a water inlet of the process water chamber 5 .

Process water is drained from the process water chamber 4 into a process water tank 19 , while the process water is drained into a process water tank 20 . Process water tank 19 and/or process water tank 20 can each be permanently installed or alternatively designed to be removable.

The electrical household appliance 1 also has a first pump 21 which is intended to pump water from the service water tank 19 back into the service water chamber 4 . For this purpose, a pressure side of the pump 21 is connected here, for example, to an outlet side of the shut-off valve 13 and an inlet side of the particle filter 14, that is to say it opens out On the outlet side between shut-off valve 13 and particle filter 14 . Analogously, a second pump 22 is present, which is intended to pump water from the process water tank 20 back into the process water chamber 5 . For this purpose, a pressure side of the pump 22 is connected here, for example, to an outlet side of the shut-off valve 16 and an inlet side of the particle filter 17, i.e. it opens out between the shut-off valve 16 and the particle filter 17.

The service water tank 19 is connected on the outlet side to a further shut-off valve 23, which on the other hand is connected to a shut-off valve 24, which in turn is connected to a general drain of the electrical household appliance 1, and a shut-off valve 25, which on the other hand serves as a service water connection for water-carrying consumers or functional units of the electrical household appliance 1. connected. There is also a shut-off valve 26 which can shut off the process water chamber 5 and the process water tank 20 from the shut-off valves 24 and 25 .

The shut-off valves 12, 13, 15, 16, 18 and 23 to 26 and the pumps 21 and 22 can be controlled by the electrical household appliance 1, e.g. by means of a corresponding control device (not shown).

For example, the initially empty intercalation filter 2 can be filled with fresh water, for which purpose the valves 12, 13, 15, 16 and 18 have been opened and the remaining valves 23 to 26 are closed, for example.

A filter process can then be started - eg by a user or automatically. The flow of process water can be continuous or circulating. In the case of continuous flow, the process water chamber 5 is always supplied with fresh water. Since the concentration of the substances to be removed in the process water is minimal, the process water is decalcified particularly quickly. For flow operation of the process water, the valves 12, 16, 18, 24 and 26 can be opened continuously or in phases, for example, so that fresh water can flow through the filter 11, the valve 12, the valve 16, the filter 17, the valve 18, the process water chamber 5, the valve 16 and the valve 24 flows into the drain of the electrical household appliance 1. Alternatively, the process water can be circulated. The water consumption is advantageously kept low, but the filter effect decreases with increasing concentration of the substances to be removed in the process water. Accordingly, the time required to achieve a defined decalcification of the process water will increase. The circulatory operation of the process water can be carried out, for example, by closing the valves 16 and 26, opening the valve 18 and activating the second pump 22.

If the process water is circulated, at some point the concentration of impurities in the process water will be so high that the filter effect of the intercalation filter 7 will drop to an unacceptable level, since it takes too long to generate a certain amount of process water. This point in time can be delayed by the presence of the—optional—process water tank 20 . When this point is reached, the highly concentrated process water must be drained and replaced. The highly concentrated process water can be replaced with fresh water, for example by opening valves 24 and 26 or valves 12, 16 and 18. To improve the filter effect right at the beginning after refilling the process water chamber 5, it is advantageous to use process water as new process water to be used, e.g. by removing it from the service water tank 19.

When replacing the process water, it may generally be beneficial to perform a thorough rinsing of the filter system. This can include flushing the intercalation filter 2 and possibly also the service water tank 19 and/or the process water tank 20 and the corresponding pipes. It is particularly advantageous if the polarity at the electrodes 8, 9 is reversed during flushing, because in this way the impurities stored in the intercalation volume can be at least partially relocated and subsequently removed from the system.

In principle, the process water side can also be operated continuously or in a cycle. In the present case, it is particularly advantageous if process water is generated in a circuit, since the water hardness can be reduced particularly far in this way. If service water is drained from the service water tank 19 for use with a water-carrying consumer, fresh water can be refilled. The service water can also be circulated independently of any other operation of the electrical household appliance 1 (eg at night, in particular started automatically) to heavily decalcified or softened water To keep a sufficient quantity of industrial water in the industrial water tank 19 or to produce it in stock. The decalcifying or filtering process can therefore be a process that is carried out independently.

In general, the decalcifying system 2 to 26 shown can also work effectively with a quantity ratio of service water to process water of approximately 10:1. The effectiveness of descaling increases as the ratio decreases. In general, the volume of the process water tank 20 can be less than the volume of the service water tank 19.

The available quantity of process water can be increased if heavily decalcified process water is mixed with fresh water again. Here, the lime content in the service water increases again somewhat, but is typically still noticeably softer than pure fresh water.

2 shows a more detailed sketch of an intercalation filter 2, 2a according to a first exemplary embodiment. The service water chamber 4 has a water inlet 27 and a water outlet 28 , while the process water chamber 5 has a water inlet 29 and a water outlet 30 . The intercalation volume 7 serves as a dividing wall between the service water chamber 4 and the process water chamber 5 and can be designed to be water-impermeable or poorly water-permeable. The intercalation volume 7 is therefore arranged non-crossing in relation to the service water chamber 4 and the process water chamber 5 .

The first electrode 8 located in the process water chamber 4 is designed here as a positive pole, while the electrode 9 located in the process water chamber 5 is designed as a negative pole. A voltage difference applied to the electrodes 8, 9 is advantageously below 1.23 volts, for example between 1 volt and 1.2 volts. If the voltage difference is present, an electric field is built up between the two electrodes 8, 9, which moves cations such as Ca ²⁺ , Mg ²⁺ , etc. into or through the intercalation volume 7, which are stored or held in the intercalation volume 7 . As a result, the water hardness in the service water chamber 4 is reduced, especially if the intercalation volume 7 is impermeable to anions. 3 shows a more detailed sketch of a further intercalation filter 2, 2b.

The process water chamber 4 is now separated from the process water chamber 5 by means of a separating membrane 31 which is permeable to ions, in particular only to anions, but impermeable to water. By applying the voltage difference between the two electrodes 8, 9 similar to FIG. The process water N exiting at the water outlet 28 is therefore low in both cations and anions. In this embodiment, the first intercalation volume 7a can be highly water permeable.

A second water-permeable intercalation volume 7b is optionally present in the process water chamber 5, as a result of which cations present in the process water P can also be trapped. The second intercalation volume 7b can be arranged analogously to the process water chamber 5 in the water flow between the water inlet 29 and the water outlet 30 (not shown).

Here, too, the intercalation volume 7a is arranged in the process water chamber 4 so as not to cross the flow of the process water N, and the intercalation volume 7b is arranged in the process water chamber 5 so as not to cross the flow of the process water P.

4 shows a more detailed sketch of an intercalation filter 2, 2c. Here the polarity between the electrodes 8 and 9 is reversed compared to Fig.2 and Fig.3. The first intercalation volume 7a is arranged in the service water chamber 4 between the water connections 27 and 28 on the one hand and the first electrode 8 on the other. When a voltage difference is applied between the two electrodes 8, 9, the cations flowing into the service water chamber 4 are attracted by the first electrode 8 and captured as they pass through the first intercalation volume 7a.

5 shows a more detailed sketch of an intercalation filter 2, 2d. At least the electrode that attracts cations, here: the first electrode 8 serving as the negative pole, is embedded in the first, water-permeable intercalation volume 7a. 6 shows a more detailed sketch of an intercalation filter 2, 2e. Here the first electrode 32 and the second electrode 33 are in the form of intercalation electrodes which have or consist of water-permeable, electrically conductive intercalation material. They are connected to the voltage source via metal connecting lugs 34, for example.

In the case of the above intercalation filters 2, 2a to 2d, it is advantageous for high softening efficiency and long service life if the electrodes 8, 9 are made of mats or braids made of conductive metals and/or carbon fibers, etc. Metal foils perforated like a sieve, for example, can also be used.

Features of the embodiments described above may also be interchanged or combined where possible. For example, the intercalation volumes of the intercalation filters 2b to 2e may each be located between the main unobstructed flow area of water and the membrane, or the main flow area of water may be between the intercalation filter and the membrane.

Of course, the present invention is not limited to the embodiment shown.

In general, "a", "an" etc. can be understood as a singular or a plural number, in particular in the sense of "at least one" or "one or more" etc., as long as this is not explicitly excluded, e.g. by the expression "exactly a" etc.

A numerical specification can also include exactly the specified number as well as a usual tolerance range, as long as this is not explicitly excluded. reference list

1 electrical household appliance

2 intercalation filters

3 filter housing

4 service water chamber

5 process water chamber

6 partition

7 intercalation volume

7a intercalation volume

7b intercalation volume

8 First electrode

9 Second electrode

10 fresh water supply line

11 particle filter

12 shut-off valve

13 shut-off valve

14 particle filters

15 shut-off valve

16 shut-off valve

17 particle filter

18 shut-off valve

19 service water tank

20 process water tank

21 First pump

22 Second pump

23 shut-off valve

24 shut-off valve

25 shut-off valve

26 shut-off valve

27 water inlet

28 water outlet

29 water inlet

30 water outlet 31 separation membrane

32 intercalation electrode

33 intercalation electrode

34 Terminal lug N service water

P process water

W water

Claims

23

Water-bearing electrical household appliance (1), having at least one water filter (2, 2a-2e) in the form of an intercalation filter with at least one intercalation volume (7, 7a, 7b; 32, 33), the intercalation volume (7, 7a, 7b; 32, 33) is set up to store interfering ions from the water (N) to be decalcified, and the water that has passed through the intercalation filter (2, 2a-2e) can be removed as process water (N) for operating at least one water-carrying functional unit of the electrical household appliance (1). Electrical household appliance (1) according to claim 1, wherein the intercalation filter (2, 2a-2e) at least one filter housing

(3) with a service water chamber (4) and a process water chamber (5), the two chambers (4, 5) are separated from each other practically impermeable to water (N, P) and permeable to interfering ions of at least a first polarity, at least the service water chamber ( N) at least one intercalation volume (7, 7a; 32) is assigned, which is set up to store interfering ions of a second polarity. at least one first electrode (8) of a pair of electrodes (8, 9) is housed in the service water chamber (N) and at least one second electrode (9) of the pair of electrodes (8, 9) is housed in the process water chamber (5) and from the service water chamber ( 4) the service water (N) can be removed for operating the at least one water-carrying functional unit. Electrical household appliance (1) according to Claim 2, in which the first electrode (32) and/or the second electrode (33) consists at least partially of electrically conductive intercalation material.

4. Electrical household appliance (1) according to one of claims 2 to 3, wherein the service water chamber (4) is separated from the process water chamber (5) by a partition wall which has at least one intercalation volume (7).

5. Electrical household appliance (1) according to one of Claims 2 to 3, wherein the process water chamber (4) is separated from the process water chamber (5) by a membrane (31) which is impermeable to water and permeable to the interfering ions of at least the first polarity, and at least one intercalation volume (7, 7a; 32) is housed in the service water chamber (4).

6. Electrical household appliance (1) according to one of the preceding claims 2 to 4, wherein the at least one intercalation volume (7, 7a, 7b; 32, 33) in a non-crossing arrangement between a water inlet (27, 29) and a water outlet (28, 30) the service water chamber (4) and/or the process water chamber (5) is arranged.

7. Electrical household appliance (1) according to one of the preceding claims 2 to 4, wherein at least one intercalation volume (7, 7b; 33) is accommodated in the process water chamber (5).

8. Electrical household appliance (1) according to one of the preceding claims, wherein the service water chamber can be connected to a service water tank for storing service water, from which the service water for operating the electrical household appliance can be removed.

9. Electrical household appliance (1) according to one of the preceding claims, wherein the process water chamber (5) can be connected to a drainable process water tank (20).

10. Electrical household appliance (1) according to one of claims 2 to 9, wherein the electrical household appliance (1) is set up to lead service water (N) circulating through the service water chamber (4).

11. Electrical household appliance (1) according to one of claims 2 to 10, wherein the electrical household appliance (1) is set up to lead process water (P) in the flow through the process water chamber (5).

12. Electrical household appliance (1) according to one of claims 2 to 11, wherein the electrical household appliance (1) is set up to lead process water (P) circulating through the process water chamber (5).

13. Electrical household appliance (1) according to claim 12, wherein the electrical household appliance (1) is set up to automatically monitor when a concentration of interfering ions in the process water (P) reaches or exceeds at least one predetermined criterion and for this case at least one action for to trigger the replacement of the process water (P).

14. Electrical household appliance (1) according to claim 13, in which the electrical household appliance (1) is set up to monitor the concentration of the interfering ions in the process water (P) by means of cyclic voltammetry.

15. A method for operating a water-bearing electrical household appliance (1), in which decalcified service water (N) is generated by interfering ions in an intercalation onsvolume (7, 7a, 7b; 32, 33) of an intercalation filter (2, 2a-3d) of Electrical household appliance (1) are stored.