dishwasher

Abstract

Dishwasher, in particular household dishwasher (1), with a process control device (19) for automatic control of the operation of the dishwasher (1), with a water softening device (6) for supplying a rinsing tank (2) with softened and / or demineralized water, to which water can be supplied via a water supply device (5), wherein the water supply device (5) comprises a supply valve (7) which can be brought by the drain control device (19) into at least an open state for supplying water and into a closed state for blocking the supply of water, wherein the water softening device (6) comprises an ion exchanger (12) for softening and / or demineralizing water, a regeneration agent container (13) for preparing a regeneration brine that can be directed into the ion exchanger (12) and a switching device (21) which can be switched by the drain control device (19) such that in a first switching state (S1) water supplied from the water supply device (5) is directed into the ion exchanger (12),and that in a second switching state (S2) water supplied from the water supply device (5) is directed into the regeneration agent container (13), and , with a dispensing device (20, 25) which issues an error message if there is not a sufficient quantity of regeneration brine in the regeneration container (13) which has at least a specified minimum regeneration content, characterized in that the process control device (19) is designed such that, upon initial commissioning of the dishwasher (1), regardless of whether an error message is issued, a preparation sequence (VS) is performed which is not performed upon subsequent commissioning, wherein the preparation sequence (VS) comprises at least one filling step (FS) during which the feed valve (7) is opened and the switching device (21) is switched to the second switching state (S2) in order to direct supplied water into the regeneration agent container (13), and wherein, after the filling step (FS), at least one rinsing step (DS) is performed during which the feed valve (7) is opened and the switching device (21) is switched to the first switching state (S1) in order to direct supplied water into the ion exchanger (12).

Description

[0001] The invention relates to a dishwasher, in particular a household dishwasher, with a process control device for the automatic control of the dishwasher's operation, with a water softening device for supplying a rinsing tank with softened and / or demineralized water, to which water can be supplied via a water supply device, wherein the water supply device comprises a supply valve which can be brought by the drain control device into at least an open state for supplying water and into a closed state for blocking the supply of water, wherein the water softening device comprises an ion exchanger for softening and / or demineralizing water, a regeneration agent container for preparing a regeneration brine that can be directed into the ion exchanger, and a switching device which can be switched by the drain control device such that in a first switching state, water supplied from the water supply device is directed into the ion exchanger, and that in a second switching state, water supplied from the water supply device is directed into the regeneration agent container, and with an output device that issues an error message if there is not a sufficient quantity of regeneration brine in the regeneration container, which has at least a specified minimum regeneration content.

[0002] From DE 196 43 151 B4, a dishwasher is known which has an ion exchanger, a salt reservoir, and a sensor device for checking whether the salt reservoir contains a sufficient quantity of brine with a sufficient salt concentration, i.e., regeneration brine. It is designed so that the operator manually fills the salt reservoir with a predetermined quantity of water and a predetermined quantity of regeneration salt before the first wash cycle. However, it can happen that some of the regeneration salt is spilled during this process, and this spilled salt then remains in the dishwasher's wash tub until the first wash cycle.Furthermore, in the well-known dishwasher, if the sensor detects a lack of brine before the first wash cycle, water is automatically added to the salt reservoir. This is because it is assumed that the operator has added regeneration salt but not water. However, if the sensor malfunctions, this automatic water addition can also be triggered if the operator has already added water, causing the salt reservoir to overflow. This results in a significant amount of regeneration brine (i.e., regeneration brine) entering the wash tub, where it remains until the first wash cycle.

[0003] A disadvantage of the well-known dishwasher is that any spilled salt and / or overflowing brine can lead to corrosion of the wash tub and / or corrosion of the dishes being washed.

[0004] From DE 44 23 866 A1, a water-bearing household appliance is known, comprising a work container for receiving the items to be washed and a salt container whose filling opening is located in the work container and can be closed by means of a lid. To reduce or prevent corrosion caused by brine, a sensor device is provided that detects when the lid is opened and / or when salt is added to the salt container and generates control measures for directly or indirectly initiating a rinse cycle.

[0005] The object of the present invention is to provide a dishwasher equipped with a water softening device in which these disadvantages are avoided.

[0006] The problem is solved in a dishwasher of the type mentioned above by designing the process control device in such a way that, upon initial commissioning of the dishwasher, a preparation sequence is carried out, regardless of whether an error message is displayed, which is not carried out during subsequent commissioning. The preparation sequence includes at least one filling step, during which the feed valve is opened and the switching device is switched to the second switching state in order to direct supplied water into the regeneration agent container. After the filling step, at least one rinsing step is carried out, during which the feed valve is opened and the switching device is switched to the first switching state in order to direct supplied water into the ion exchanger.

[0007] In the dishwasher according to the invention, the dishes to be washed are placed in a washing container and cleaned there in a washing process, also called a washing cycle, with the aid of water and then dried.

[0008] The dishwasher is equipped with a control unit that automatically regulates the wash cycle according to a typically selectable wash program. The water required to operate the dishwasher can be supplied, for example, from an existing water supply installed in the building.

[0009] It is known that a high calcium and / or magnesium content in the water used in a dishwasher is detrimental to the washing result, as the calcium deposits can adhere to the items and cause undesirable cloudiness, particularly in glassware. Therefore, in the dishwasher according to the invention, the incoming water is first passed through a water softening unit to soften or decarbonize it before being used for a wash or rinse cycle.

[0010] To supply water to the water softener, a water supply device is provided, which includes a supply valve that can be set by the drain control device to at least one open position for supplying water and one closed position for blocking the water supply. The water required for this can be drawn directly from an external water supply, for example, from a building-integrated water supply, via the water supply device. However, it is also conceivable that at least some of the water is drawn by the water supply device from at least one reservoir of the dishwasher.

[0011] The water softening device comprises an ion exchanger for softening and / or desalinating water, a regeneration container for preparing a regeneration brine that can be directed into the ion exchanger, and a switching device which can be switched by the flow control device in such a way that in a first switching state, water supplied from the water supply device is directed into the ion exchanger, and that in a second switching state, water supplied from the water supply device is directed into the regeneration container.

[0012] The ion exchanger contains a resin that absorbs calcium and / or magnesium ions dissolved in the water, thereby reducing the water's lime content. When this switching device is in the first switching state, water can be softened and / or demineralized and supplied to the dishwasher tank.

[0013] The regeneration agent container for preparing a regeneration brine that can be directed into the ion exchanger is intended to remove the sorbed lime from the resin of the ion exchanger, i.e., to maintain it.

[0014] The maintenance of an ion exchanger typically includes a regeneration step and a rinsing step. During the regeneration step, a regeneration brine, previously prepared from water and regenerating agent (e.g., regeneration salt), is added to the ion exchanger. This brine may essentially contain sodium chloride in aqueous solution. As soon as this regeneration brine comes into contact with the ion exchanger resin, the sodium ions contained in the regeneration brine are adsorbed by the resin instead of the calcium and / or magnesium ions, while the calcium and / or magnesium ions from the resin dissolve into the regeneration salt-containing brine.

[0015] The regeneration brine is typically prepared in the regeneration agent container and kept ready until the start of the regeneration process. At the beginning of the regeneration process, the regeneration brine is then fed from the regeneration agent container into the ion exchanger by opening the feed valve and switching the changeover device to the second switching position. This causes a predetermined amount of regeneration brine to be displaced from the regeneration agent container by the incoming water. To facilitate this displacement, it is advantageous to design the regeneration container such that only when it is completely filled with water and / or regeneration brine is the newly inflowing water forced through an outlet, e.g., in the upper part of the regeneration container, into the ion exchanger container, which is continuously connected to the regeneration container via the changeover device in the second switching position.Advantageously, the regeneration agent tank, the ion exchange tank, and / or the switching device are designed to be interconnected in such a way that, particularly during the filling step of the preparation sequence, the regeneration brine forced out of the regeneration agent tank by the newly flowing water is directed into the ion exchange tank or ion exchanger when the regeneration agent tank is full. After a period of time required for the regeneration of the ion exchanger, the ion exchanger is flushed with water drawn in by the water supply system in a flushing step. This is achieved by opening the supply valve and switching the device to its first switching state, thus removing the regeneration brine from the ion exchanger so that it is again available for water softening.

[0016] The output device for issuing an error message when there is an insufficient quantity of regeneration brine in the regeneration tank, containing at least a predetermined minimum regeneration agent concentration, can include a float whose density is greater than that of water but less than that of regeneration brine. This causes the float to rise in a minimum quantity of regeneration brine that meets the predetermined minimum regeneration agent concentration, while it falls if the quantity of regeneration brine or the regeneration agent concentration in the brine is too low. This rise or fall of the float can be displayed directly, for example, via a sight glass. Alternatively, the rise or fall of the float can be detected by a sensor, such as a magnetic sensor or a light barrier.

[0017] To prepare the regeneration brine in the regeneration agent container and keep it ready until the start of a regeneration cycle, the operator must manually fill the regeneration agent container with water and regeneration agent when the dishwasher is first operated. Four scenarios are conceivable: 1. The operator adds neither water nor regenerant. In this case, an error message is initially displayed. However, contamination of the rinse tank with regenerant is naturally impossible in this scenario. While the regenerant tank is at least partially filled with water during the filling step, no regenerant brine is formed, which is detected by the sensor, so the error message continues to be displayed. If an initial rinse cycle is now performed without regenerant brine, this is generally harmless, as regeneration of the ion exchanger is not usually necessary during the first rinse cycle. The operator will still be prompted to add regenerant so that they can correct their error later. 2. The operator adds water but no regeneration agent. In this case, an error message is initially displayed. However, contamination of the rinse tank with regeneration agent is also ruled out. Although the regeneration agent tank is at least partially filled with water during the filling step, no regeneration brine is formed, which is detected by the sensor, so the error message continues to be displayed. If an initial rinse cycle is now performed without regeneration brine, this is generally harmless, as regeneration of the ion exchanger is not usually necessary during the first rinse cycle. The operator will still be prompted to add regeneration agent so that they can correct their error later. 3. The operator adds regeneration solution but no water. In this case, an error message is initially displayed. Then, during the filling step, the regeneration solution container is automatically at least partially filled with water, forming a regeneration brine solution. This is detected by the sensor, causing the initial error message to disappear. This prevents the operator from attempting to add more regeneration solution to the already full container, which would lead to severe contamination of the wash tank by overflowing solution. It also prevents the operator from assuming a malfunction by associating the error message solely with a lack of regeneration solution, not a lack of water.

[0018] Any regenerant spilled during the filling of the rinsing tank can be flushed away by the water from the rinsing step, thus automatically removing any contamination of the rinsing tank. Since the regenerant tank is now at least partially filled with water, it will be completely filled with water or regenerant brine after just a few regeneration cycles, in which a predetermined amount of water is added to the tank as described above. This ensures that during a regeneration cycle, the regenerant brine is displaced as intended and directed from the regeneration tank, particularly via the switching device, into the ion exchanger.

[0019] 4. The operator adds regeneration agent and water. In this case, an error message is initially displayed, but this disappears when the regeneration agent has dissolved sufficiently in the water and a regeneration brine has formed. During the filling step, however, the already filled regeneration agent container overflows, so that regeneration brine enters the rinsing tank.

[0020] However, the overflowing regeneration brine and the regeneration agent spilled during filling can be flushed away by the water from the rinsing step of the preparation step, so that contamination of the rinsing container is automatically removed.

[0021] In the dishwasher according to the invention, it is thus ensured that – unlike in the dishwasher of DE 196 43 151 B4 – any regeneration agent spilled during the initial start-up of the dishwasher is always removed by the continuous rinsing step. It is also ensured that any regeneration brine that overflows during the filling step is always removed by the continuous rinsing step. This applies – unlike in the dishwasher of DE 196 43 151 B4 – even if the dispensing device malfunctions, since the preparation sequence according to the invention is always carried out regardless of any error message issued by the dispensing device. Overall, this prevents corrosion of the wash tank, other parts of the dishwasher, and / or the items being washed.

[0022] Furthermore, it is ensured that an error message is only permanently displayed if no or too little regenerant has been added. If only no or too little water has been added, the error message is automatically cleared by the dishwasher itself after the wash cycle has been completed, thus eliminating the risk of the operator misinterpreting the error message.

[0023] According to a further advantageous embodiment of the invention, it is provided that during the filling step(s) the regeneration agent container is supplied with a total of no more than 70%, preferably no more than 60%, and particularly preferably no more than 50%, of its nominal capacity in water, wherein the dispensing device is designed such that no error message is triggered during such filling, provided the specified minimum regeneration agent content is maintained. In this way, the amount of regeneration brine that overflows during the filling step in the case of a regeneration agent container already filled with water can be limited, which restricts the loss of regeneration agent and facilitates the removal of the overflowing regeneration brine during the rinsing step.

[0024] According to an advantageous embodiment of the invention, at least 100%, preferably at least 200%, and particularly preferably at least 300% of the nominal capacity of the regeneration agent container is supplied to the ion exchanger during the rinsing step(s). This ensures the reliable removal of any regeneration agent spilled during filling, as well as any overflowing regeneration brine.

[0025] According to an advantageous embodiment of the invention, a circulation pump for circulating water in the washing tank is switched off during the preparation sequence. This prevents any spilled salt and / or brine from being distributed in the washing tank during the preparation sequence, which could promote corrosion of the washing tank and / or the dishes being washed.

[0026] According to an advantageous embodiment of the invention, a water inlet for introducing the water supplied by the water softening device into the rinsing tank is arranged such that the supplied water flows over an area around a regeneration agent filling opening, which is provided for filling the regeneration agent container. This allows for particularly effective removal of spilled salt.

[0027] According to an advantageous embodiment of the invention, the sequence control device is designed such that the preparation sequence is performed when the dishwasher is switched on for the first time. In this case, the system checks whether this is the first time the dishwasher is being used and, if necessary, performs the preparation sequence before a wash program is selected for the first time. This eliminates the need to perform redundant checks for each individual wash program.

[0028] According to an advantageous embodiment of the invention, it is particularly provided that the process control device is designed such that the preparation sequence is carried out when a rinsing program stored in the process control device is called up for the first time to control a rinsing cycle for cleaning items. This prevents the preparation sequence from being carried out at a time when the operator does not yet intend to perform a rinsing cycle and has therefore intentionally not yet filled the regeneration agent container.

[0029] According to an advantageous embodiment of the invention, the preparation sequence includes a first pumping step, performed before the filling step, to pump water from the rinsing tank to an external wastewater disposal system using a pump or drain pump. This removes water from the rinsing tank that could otherwise contribute to the widespread distribution of spilled salt or overflowing regeneration brine. This reduces the risk of corrosion.

[0030] According to a further advantageous embodiment of the invention, the preparation sequence includes a second pumping step, performed after the filling step, for pumping water from the rinsing tank to an external wastewater disposal system using a pump or drain pump. In this way, most of the regeneration brine that overflowed during the filling step can be removed promptly, further reducing the risk of corrosion.

[0031] According to a practical embodiment of the invention, the preparation sequence comprises several rinsing steps performed at intervals. This prevents the formation of preferential channels in the ion exchanger, which, based on experience, can occur with prolonged flow through the ion exchanger due to a rearrangement of the ion exchange material, particularly with magnesium and / or lime particles, while simultaneously ensuring the supply of the required amount of water.

[0032] According to a further advantageous embodiment of the invention, the preparation sequence after the at least one rinsing step includes at least one further pumping step for pumping water from the rinsing tank to an external wastewater disposal system using a pump or drain pump. In this way, the water generated during the rinsing step, which contains traces of regenerant, can be largely removed promptly, further reducing the risk of corrosion.

[0033] According to an advantageous embodiment of the invention, the water supply device includes a water flow meter for determining the quantity of water supplied to the water softening device. This allows for more precise control of the quantity of water supplied to the water softening device than would be possible with a purely time-controlled preparation sequence.

[0034] According to a preferred embodiment of the invention, the preparation sequence includes a functional test step for the water flow meter, performed before the filling step. This ensures that the water softener receives the correct amount of water during the filling and / or rinsing steps. During the functional test step, a small amount of water can be supplied to the water softener by opening the feed valve at a controlled time, and the plausibility of the water flow meter signal can be checked.

[0035] According to an advantageous further development of the invention, the dispensing device comprises a sensor arranged in a region of the regeneration agent container for generating the error message and a separate user interface for displaying the error message to an operator. This increases the ease of use of the dishwasher compared to solutions where error messages are displayed directly, for example via a sight glass on the regeneration agent container.

[0036] Furthermore, the invention relates to a method for operating a dishwasher, in particular for operating a dishwasher according to the invention. with a process control device for the automatic control of the dishwasher's operation, with a water softening device for supplying a rinsing tank with softened and / or demineralized water, to which water can be supplied via a water supply device, wherein the water supply device comprises a supply valve which can be brought by the drain control device into at least an open state for supplying water and into a closed state for blocking the supply of water, wherein the water softening device comprises an ion exchanger for softening and / or demineralizing water, a regeneration agent container for preparing a regeneration brine that can be directed into the ion exchanger, and a switching device which can be switched by the drain control device such that in a first switching state, water supplied from the water supply device is directed into the ion exchanger, and that in a second switching state, water supplied from the water supply device is directed into the regeneration agent container, and with an output device that issues an error message if there is not a sufficient quantity of regeneration brine in the regeneration container, which has at least a specified minimum regeneration content, wherein, upon initial commissioning of the dishwasher, regardless of whether an error message is displayed, a preparation sequence is performed which is not performed during subsequent commissioning, wherein the preparation sequence includes at least one filling step during which the feed valve is opened and the switching device is switched to the second switching state in order to direct supplied water into the salt container, and wherein, after the filling step, at least one rinsing step is performed during which the feed valve is opened and the switching device is switched to the first switching state in order to direct supplied water into the ion exchanger.

[0037] Advantages, developments and further developments of the method according to the invention are explained in the description of the claimed dishwasher.

[0038] The advantageous embodiments and further developments of the invention described above and / or described in the dependent claims can be used individually or in any combination with each other, except, for example, in cases of clear dependencies or incompatible alternatives.

[0039] The invention and its advantageous embodiments and further developments, as well as their advantages, are explained in more detail below with reference to the drawings. These show, in each case in a schematic principle sketch: Fig. 1 a schematic spatial representation of an embodiment of a dishwasher according to the invention; Fig. 2 a block diagram of the dishwasher according to the invention Fig. 1; Fig. 3 a flowchart to explain the function of the dishwasher according to the invention Fig. 1.

[0040] In the following figures, corresponding parts are provided with the same reference numerals. Only those components of a dishwasher necessary for understanding the invention are provided with reference numerals and explained. It is understood that the dishwasher according to the invention may comprise further parts and assemblies.

[0041] Fig. Figure 1 shows a schematic spatial representation of an embodiment of a dishwasher 1 according to the invention. This dishwasher has a wash tank 2 which can be closed by a door 3, thus creating a wash chamber for washing dishes. The wash tank 2 is arranged inside a housing 4 of the dishwasher 1, which can have standard dimensions. For example, the housing 4 can have a width of 45 cm or 60 cm, which allows the dishwasher 1 to be integrated into a standard kitchen unit with a corresponding installation niche.

[0042] The dishwasher 1 has a schematically depicted water supply device 5, which is designed to supply water to a water softener 6 for filling the wash tank 2 with softened and / or demineralized water. In the exemplary embodiment, the water supply device 5 is designed to receive water from an external water supply, with the received water being supplied to the water softener 6 without intermediate storage. However, water supply devices are also conceivable in which the water supplied to the water softener 6 is taken from an internal water reservoir of the dishwasher.

[0043] In the exemplary embodiment, the water supply device 5 comprises a controllable supply valve 7, which can, for example, be designed as a solenoid valve 7. The inlet side of the supply valve 7 is designed so that it can be attached to a connection fitting WH of a building's water supply, for example, to a tap WH. The connection can be made by means of a screw connection, a snap connection, or the like. Such a supply valve 7 is also known as an aquastop valve. Advantageously, this valve is closed when it is not actuated, so that the dishwasher 1 is disconnected from the water supply when switched off. In this way, leakage of water from the switched-off dishwasher 1 can be prevented in the event of a malfunction.

[0044] As intended, in Fig. 1. The inlet side of the supply valve 7 is connected to a tap WH. The outlet side of the supply valve 7 is connected to a supply hose 7, with the downstream end of the supply hose 8 being connected to an inlet side of a housing-mounted connector 9. Therefore, by means of the water supply device 5, it is possible to supply water from the external water supply WH to the water softening device 6 of the dishwasher 1 in a controlled manner.

[0045] The supply hose 8 can be designed as a safety hose with an inner water-carrying pressure hose and an outer protective hose. A leakage water channel can be provided between the pressure hose and the protective hose to drain any leakage water that may occur, so that any leakage water that occurs in the area of ​​the supply hose 8 during operation of the dishwasher 1 is directed into the interior of the dishwasher 1 via the housing-mounted connection piece 9. Here it can be detected by a leakage water sensor (not shown), so that appropriate measures, such as closing the inlet valve 7, can be initiated.

[0046] Downstream of the fixed connection piece 9, the water supply device 5 may have a free flow path 10. This free flow path 10 is a so-called pipe interruption, which serves to prevent backflow of water from the dishwasher 1 if a negative pressure occurs in the external water supply due to dynamic processes. This prevents, in particular, previously used water, which may contain dirt, cleaning agents, and / or cleaning aids, from flowing back into the building's water supply.

[0047] Furthermore, the water supply device 5 can have a water flow meter 11, which makes it possible to determine the amount of water supplied via the water supply device 5.

[0048] The water softening device 6 comprises an ion exchanger 12 for softening and / or demineralizing water and a regeneration agent container 13, which is equipped with a regeneration agent filling opening 14 located at the bottom of the rinsing container 2 and accessible and closable from the interior of the rinsing container 2 for filling a regeneration agent.

[0049] The water softened by the water softening device 6 can be fed into the rinsing tank via a water inlet 15. The water inlet 15 is advantageously arranged so that the area of ​​the regeneration agent filling opening 14 is surrounded by the incoming water. This ensures that any regeneration agent spilled during filling is flushed away.

[0050] In a lower section of the wash tank 2, a pump housing 16 is provided for collecting the water contained in the wash tank 2. This housing advantageously contains a circulation pump for circulating the water in the wash tank 2 during a wash cycle. The circulation pump may include a heating element for heating the water in the wash tank 2, for example, an instantaneous water heater. Likewise, a pump for draining water, for example, at the end of a wash cycle, may be provided in the pump housing 16. However, the various pumping functions can also be performed by a single pump in conjunction with switchable valves.The pump housing 16 is generally connected to a wastewater connection piece 17 by means not shown, such that water from the flushing tank 2 can be pumped via a wastewater hose 18 connected to the wastewater connection piece 17 into a wastewater installation A on the building side, for example a wastewater pipe A.

[0051] Dishwasher 1 also has a flow control unit 19 for controlling the execution of a wash program. Various wash programs can be stored in the flow control unit 19, which can be selected by an operator. The flow control unit 19 is located inside the door 3 of the wash tub 2, but could also be located elsewhere in the dishwasher 1.

[0052] Likewise, at door 3 or at another easily accessible location, there is an operator interface 20 that interacts with the process control device 19 and enables the input of operating commands by a user and the output of information to the user.

[0053] Fig. Figure 2 shows a schematic functional diagram of the dishwasher. Fig. 1. The illustration does not correspond to the spatial arrangement of the individual components of the dishwasher 1. The feed valve 7 and a switching device 21 of the water softener 6 are each connected to the drain control unit 19 in such a way that both can be controlled individually. The switching device 21 can be switched by the drain control unit 19 such that, in a first switching state S1 (represented by a dotted line), water supplied from the water feed unit 5 is directed into the ion exchanger 12, and that, in a second switching state S2 (represented by two dashed lines), water supplied from the water feed unit 5 is directed into the regeneration agent container 13. This makes it possible to fill the wash tub 2 of the dishwasher 1 either exclusively via the ion exchanger 12 or first via the regeneration agent container 13 and then via the ion exchanger 12.In the second switching state S2 of the switching device 21, the regeneration agent tank 13 and the ion exchanger are connected to each other via one or more communicating pipes. If the regeneration tank is full, further water inflow forces water and / or regeneration brine into the ion exchanger tank. Simultaneously, a corresponding quantity of liquid is forced from the ion exchanger tank into the rinsing tank via the water inlet.

[0054] A circulation pump 22, designed as a heating pump 22, is arranged in the pump housing 16 of the wash tank 2. This pump is connected to a spray system 23 located inside the wash tank 2. This allows items to be sprayed with water during a wash cycle to clean them. A drain pump 24 is also located in the pump housing. This pump removes excess water (including any additives such as dirt, detergent, regenerant, etc.). Both the heating and pump functions of the heating pump 22 can be individually controlled by the drain control unit 19. The drain control unit 19 is also connected to the drain pump 24 for its control.

[0055] Fig. Figure 3 shows an exemplary flowchart to explain the function of the dishwasher according to the invention. Fig. 1.

[0056] According to the invention, it is provided that during the initial commissioning of the dishwasher 1, regardless of whether an error message is issued, a preparation sequence VS is carried out which is not carried out during subsequent commissioning and which is automatically controlled by the process control device 19.

[0057] In this embodiment, each time one of the wash programs stored in the sequence control unit 19 is called (i.e., each time a program starts), an AEP query is performed to determine whether this is the first time a program PS has been started on the dishwasher 1. The AEP query could also be performed each time the dishwasher is switched on, for example, using a main switch (not shown). The selection of a specific wash program and / or the start of the selected wash program (PS) can be initiated by the operator at the user interface 20. This query can be performed using a program counter (not shown) that continuously counts the number of wash programs executed. Alternatively, a binary memory can be used, containing a first value at the factory and a second value after the first call to a wash program.If the query determines that this is the first time one of the washing programs has been called, a preparation sequence (VS) is executed. Otherwise, the process proceeds directly to the program continuation step (PF) without a preparation sequence (VS).

[0058] Preferably, the circulation pump 22 for circulating water in the wash tank 2 is switched off during the preparation sequence VS. This prevents any spilled salt and / or overflowing brine from being distributed in the wash tank 2 during the preparation sequence VS, which could promote corrosion of the wash tank 2 and / or the corrosion of dishes being washed.

[0059] The preparation sequence VS comprises a filling step FS, during which the feed valve 7 is opened and the switching device 21 is switched to the second switching state S2 in order to direct supplied water into the regeneration agent container 13. It can be provided that during the filling step, the regeneration agent container 13 is supplied with a total of at most 70%, preferably at most 60%, and particularly preferably at most 50% of its nominal capacity, of water, wherein the dispensing device 20 is designed such that no error message is generated during this filling process, provided the specified minimum regeneration agent content is maintained.In this way, the amount of regeneration brine that overflows during the filling step FS in the case of a regeneration container 13 that is already filled with water can be limited, which limits the loss of regeneration and facilitates the removal of the overflowing regeneration brine in the rinsing step DS.

[0060] Advantageously, the preparation sequence VS includes, in particular, a functional test step FPS for the water flow meter 11, which is performed before the filling step FS. This ensures that the softening unit 6 receives the correct amount of water during the filling step and / or the rinsing step. During the functional test step, a small amount of water can be supplied to the softening unit by opening the supply valve at a controlled time, and the plausibility of the signal from the water flow meter can be checked.

[0061] Before the filling step FS, a switching step US2 can be provided to actively bring the switching device 21 into the second switching state S2.

[0062] After the filling step FS, a switching step US1 may still be provided to actively return the switching device 21 to the first switching state S1.

[0063] Advantageously, the preparation sequence VS includes a first pumping step AP1, performed before the filling step FS, to pump water from the rinsing tank 2 to an external wastewater disposal facility A using a pumping or deionizing pump 24. This removes water from the rinsing tank 2, which could otherwise contribute to the widespread distribution of spilled salt or overflowing regeneration brine. This reduces the risk of corrosion.

[0064] It is also expedient that the preparation sequence VS includes a second pumping step AP2, performed after the filling step FS, for pumping water from the rinsing tank 2 to an external wastewater disposal facility A using a pumping or deionizing pump 24. In this way, most of the regeneration brine that overflowed during the filling step FS can be removed promptly, further reducing the risk of corrosion.

[0065] Furthermore, after the filling step FS, a predetermined number of flushing steps DS are carried out, during which the feed valve 7 is opened and the switching device 21 is switched to its first switching state in order to direct the supplied water into the ion exchanger 12. It can be provided that during the flushing steps, at least 100%, preferably at least 200%, and particularly preferably at least 300% of the nominal capacity of the regeneration agent container 13 is supplied with water to the ion exchanger 12. In this way, the reliable removal of any regeneration agent spilled during filling, as well as any overflowing regeneration brine, is ensured.

[0066] Advantageously, the preparation sequence VS is designed to include several rinsing steps DS, which are performed at intervals. This prevents the formation of preferential channels in the ion exchanger 12, which, based on experience, can occur during prolonged flow through the ion exchanger 12 due to a rearrangement of the ion exchange material, while simultaneously ensuring the supply of the required amount of water.

[0067] Advantageously, the preparation sequence VS includes, after at least one rinsing step, a further pumping step APD for pumping water from the rinsing tank 2 to an external wastewater disposal facility A using a pumping or draining pump 24. In this way, the water generated in the rinsing step DS, which contains traces of regenerant, can be largely removed promptly, further reducing the risk of corrosion.

[0068] In this embodiment, a further pump-out step (APD) is performed after each of the flushing steps (DS). After each of these subsequent pump-out steps, a query step (ADE) is performed to determine whether the intended number of flushing steps has already been reached. If not, another flushing step (DS) is preferably performed, followed by another pump-out step (APD). If, however, the intended number has been reached, the preparation sequence (VS) is terminated, and the program proceeds to the program continuation step (PF).

[0069] In the described procedure, if the salt container 13 is not pre-filled with water and if a salt indicator 20 functioning by brine buoyancy (float) is used, or if a purely optical salt shortage indicator is used, or if a combination of both types is used, a safe acknowledgment, i.e. switching off the salt indicator 20, for example a salt shortage indicator light, is ensured.

[0070] In this example, this is achieved by a single filling step FS performed at the beginning of the program PS, using a quantity of water of, for example, 0.7 liters. This quantity can also be varied as required.

[0071] A complete rinsing cycle is then performed on the ion exchanger 12 to flush out the salt and hardness-causing minerals contained within it. This rinsing is preferably carried out in, for example, 6 individual steps (DS), each using, for example, 0.8 liters of water, with pauses of, for example, 5 seconds between each step. These pauses prevent the formation of preferential channels in the exchange resin. The number and volume of the rinsing steps (DS) can also be varied.

[0072] This rinsing process, which preferably takes place without circulation, greatly dilutes the brine that may have been displaced during regeneration, as well as any salt that overflowed during salt filling, and pumps it out of the washing container without cutlery or the washing container, e.g. made of stainless steel, coming into contact with it.

[0073] A water inlet flowing in from the side near the sink base surrounds the salt container filling area and washes salt lying on the bottom into the pump pot, where it is diluted and pumped out.

[0074] As a result, the risk of corrosion during subsequent rinsing baths with circulation is no longer present due to the greatly reduced salt content.

[0075] The described procedure ensures minimal chloride contamination of the items being washed, especially the stainless steel dishes and the stainless steel washing container, throughout the entire lifespan of the appliance.

[0076] The aforementioned method was able to demonstrate a reduction in the salt content in the rinse bath immediately following initial commissioning from 6000 mg / l to 1500 mg / l in tests.

[0077] In summary, when the dishwasher is first put into operation, a special preparation sequence is necessarily carried out, which includes at least one filling step to fill the regeneration agent container and at least one subsequent rinsing step to rinse the ion exchanger or its container. Reference symbol list 1 dishwasher 2 washing containers 3 Door 4 cases 5 Water supply system 6 Water softener 7 Supply valve 8 Feed hose 9 housing-mounted connector 10 free flow section 11 Water flow meters, impeller meters 12 ion exchangers 13 regeneration containers 14 Regenerant filling opening 15 Water inlet 16 Pump pot 17 Wastewater connection piece 18 wastewater hose 19 Flow control device 20 User interface 21 Switching device 22 Circulation pump with instantaneous water heater 23 Spray device 24 Drain pump, wastewater pump 25 Sensor WH water supply, tap A wastewater disposal facility, wastewater pipe RM Regenerating Agent S1 first switching state of the switching device S2 second switching state of the switching device PS Program start AEP query “First program start?” VS Preparation Sequence PF Program Continuation AP1 first pumping step FPS functional test step for water flow meter US2 Switching step to assume the second switching state FS Filling Step US1 Switching step to assume the first switching state AP2 second pumping step DS flushing step APD further pumping step after flushing step ADE query “Have the planned number of flushing steps been reached?” PF Program Continuation

Claims

[1] Dishwasher, especially household dishwasher (1), with a process control device (19) for automatic control of the operation of the dishwasher (1), with a water softening device (6) for supplying a rinsing tank (2) with softened and / or demineralized water, to which water can be supplied via a water supply device (5), wherein the water supply device (5) comprises a supply valve (7) which can be brought by the drain control device (19) into at least an open state for supplying water and into a closed state for blocking the supply of water, wherein the water softening device (6) comprises an ion exchanger (12) for softening and / or demineralizing water, a regeneration agent container (13) for preparing a regeneration brine that can be directed into the ion exchanger (12) and a switching device (21) which can be switched by the drain control device (19) such that in a first switching state (S1) water supplied from the water supply device (5) is directed into the ion exchanger (12),and that in a second switching state (S2) water supplied from the water supply device (5) is directed into the regeneration agent container (13), and, with a dispensing device (20, 25) which issues an error message if there is not a sufficient quantity of regeneration brine in the regeneration container (13) which has at least a specified minimum regeneration content, characterized by, that the process control device (19) is designed such that, upon initial commissioning of the dishwasher (1), regardless of whether an error message is issued, a preparation sequence (VS) is performed which is not performed upon subsequent commissioning, wherein the preparation sequence (VS) comprises at least one filling step (FS) during which the feed valve (7) is opened and the switching device (21) is switched to the second switching state (S2) in order to direct supplied water into the regeneration container (13), and wherein, after the filling step (FS), at least one rinsing step (DS) is performed during which the feed valve (7) is opened and the switching device (21) is switched to the first switching state (S1) in order to direct supplied water into the ion exchanger (12). [2] Dishwasher according to the preceding claim, characterized by, that the regeneration agent container (13) is supplied with a total of at most 70%, preferably at most 60%, particularly preferably at most 50%, of the nominal capacity of the regeneration agent container (13) during the filling step(s) (FS), wherein the dispensing device (20, 25) is designed such that an error message is not generated during such filling, provided that the specified minimum regeneration agent content is maintained. [3] Dishwasher according to any of the preceding claims, characterized by , that the ion exchanger (12) is supplied with a total of at least 100%, preferably at least 200%, particularly preferably at least 300%, of the nominal capacity of the regeneration container (13) during the rinsing step(s) (DS). [4] Dishwasher according to any of the preceding claims, characterized by, that during the preparation sequence (VS) a circulation pump (22) for circulating water in the wash tank (2) is switched off. [5] Dishwasher according to any of the preceding claims, characterized by , that a water inlet (15) for letting the water supplied by the softening device (6) into the rinsing tank (2) is arranged such that the supplied water acts on an area around a regeneration agent filling opening (14) which is provided for filling regeneration agent into the regeneration agent container (13). [6] Dishwasher according to any of the preceding claims, characterized by , that the process control device (19) is designed such that the preparation sequence (VS) is carried out when the dishwasher (1) is switched on for the first time. [7] Dishwasher according to any of the preceding claims, characterized by, that the process control device (19) is designed such that the preparation sequence (VS) is carried out when a rinsing program stored in the process control device (19) is called up for the first time to control a rinsing cycle for cleaning items to be washed. [8] Dishwasher according to any of the preceding claims, characterized by , that the preparation sequence (VS) includes a first pumping step (AP1) carried out before the filling step (FS) to pump water from the rinsing tank (2) to an external wastewater disposal facility (A) using a pumping pump (detergent pump) (24). [9] Dishwasher according to any of the preceding claims, characterized by , that the preparation sequence (VS) includes a second pumping step (AP2) carried out after the filling step (FS) to pump water out of the rinsing tank (2) to an external wastewater disposal facility (A) using a pumping pump (lye pump) (24). [10] Dishwasher according to any one of the preceding claims, characterized by that the preparation sequence (VS) includes several flushing steps (DS) which are carried out at intervals. [11] Dishwasher according to any of the preceding claims, characterized by , that the preparation sequence (VS) after at least one rinsing step (DS) includes a further pumping step (APD) to pump water out of the rinsing tank (2) to an external wastewater disposal facility (A) using a pumping pump (detergent pump) (24). [12] Dishwasher according to any of the preceding claims, characterized by , that the water supply device (5) includes a water flow meter (11) for determining the quantity of water supplied to the softening device (6). [13] Dishwasher according to the preceding claim, characterized by, that the preparation sequence (VS) includes a functional test step (FPS) for the water flow meter (11) performed before the filling step (FS). [14] Dishwasher according to any of the preceding claims, characterized by , that the output device (20, 25) has a sensor (25) arranged in an area of ​​the regeneration container for generating the error message and an operator interface (20) separated from it for outputting the error message to an operator. [15] Method for operating a dishwasher (1), in particular for operating a dishwasher (1) according to at least one of the preceding claims, with a process control device (19) for automatic control of the operation of the dishwasher (1), with a water softening device (6) for supplying a rinsing tank (2) with softened and / or demineralized water, to which water can be supplied via a water supply device (5), wherein the water supply device (5) comprises a supply valve (7) which can be brought by the drain control device (19) into at least an open state for supplying water and into a closed state for blocking the supply of water, wherein the water softening device (6) comprises an ion exchanger (12) for softening and / or demineralizing water, a regeneration agent container (13) for preparing a regeneration brine that can be directed into the ion exchanger (12) and a switching device (21) which can be switched by the drain control device (19) such that in a first switching state (S1) water supplied from the water supply device (5) is directed into the ion exchanger (12),and that in a second switching state (S2) water supplied from the water supply device (5) is directed into the regeneration agent container (13), and, with a dispensing device (20, 21) which issues an error message if there is not a sufficient quantity of regeneration brine in the regeneration container (13) which has at least a specified minimum regeneration content, characterized by, that during the initial commissioning of the dishwasher (1), regardless of whether an error message is displayed, a preparation sequence (VS) is performed which is not performed during subsequent commissioning, wherein the preparation sequence (VS) comprises at least one filling step (VS) during which the feed valve (7) is opened and the switching device (21) is switched to the second switching state (S2) in order to direct supplied water into the regeneration container (13), and wherein after the filling step (FS) at least one rinsing step (DS) is performed during which the feed valve (7) is opened and the switching device (21) is switched to the first switching state (S1) in order to direct supplied water into the ion exchanger (12).

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