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Title:
DISHWASHER AND METHOD FOR OPERATING A DISHWASHER
Document Type and Number:
WIPO Patent Application WO/2017/209889
Kind Code:
A1
Abstract:
A commercial dishwasher for crockery or utensils, which is in the form of a box-type dishwasher (200) or in the form of a conveyor dishwasher (100), wherein the dishwasher has at least one controllable, capacitive deionization unit (50) with an inlet (71) for fresh water and an outlet (51) for demineralized water and a control device (10) which is associated at least with the deionization unit (50). The control device (10) is designed to automatically or selectively automatically adjust, preferably in a regulating manner, at least one parameter which characterizes the operation of the deionization unit (50), specifically depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

Inventors:
DISCH, Harald (155 Harlem AvenueGlenview, IL, 60025, US)
PADTBERG, Klaus (155 Harlem AvenueGlenview, IL, 60025, US)
BERNER, Dietrich (155 Harlem AvenueGlenview, IL, 60025, US)
BRAUN, Harry (155 Harlem AvenueGlenview, IL, 60025, US)
Application Number:
US2017/030986
Publication Date:
December 07, 2017
Filing Date:
May 04, 2017
Export Citation:
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Assignee:
ILLINOIS TOOL WORKS INC. (155 Harlem Avenue, Glenview, IL, 60025, US)
International Classes:
A47L15/42
Domestic Patent References:
WO2014014858A22014-01-23
WO2006045117A12006-04-27
Foreign References:
EP2857572A12015-04-08
Attorney, Agent or Firm:
NIEBERDING, Michael, J. et al. (Thompson Hine LLP, 10050 Innovation DriveSuite 40, Dayton OH, 45342-4934, US)
Download PDF:
Claims:
Patent claims

1. Dishwasher, in particular commercial dishwasher for crockery or utensils, which is in the form of a box-type dishwasher (200) or in the form of a conveyor dishwasher (100), wherein the dishwasher has at least one controllable, capacitive deionization unit (50) with an inlet (71) for fresh water and an outlet (51) for demineralized water and a control device (10) which is associated at least with the deionization unit (50), wherein the control device (10) is designed to automatically or selectively automatically adjust, preferably in a regulating manner, at least one parameter which characterizes the operation of the deionization unit (50), specifically depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

2. Dishwasher according to Claim 1, wherein the dishwasher has a manually operable interface by means of which the at least one parameter which characterizes the operation of the deionization unit (50) can be adjusted by the operator of the dishwasher.

3. Dishwasher according to Claim 1 or 2, wherein the control device (10) is designed to adjust the level of an electrical voltage which is supplied to the deionization unit (50) and is used for deionization and/or regeneration and/or the polarity of an electrical voltage which is supplied to the deionization unit (50) depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

4. Dishwasher according to one of Claims 1 to 3, wherein the deionization unit (50) has at least one cell (50a, 50b) which can be selectively operated in a deionization mode, in a regeneration mode or in a flush mode.

5. Dishwasher according to Claim 4, wherein the control device (10) is designed to select and adjust the operating mode of the at least one cell (50a, 50b), specifically depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

6. Dishwasher according to Claim 4 or 5, wherein the control device (10) is designed to adjust a cycle time of the at least one cell (50a, 50b) in the deionization mode and/or in the regeneration mode and/or the switchover frequency between the deionization mode and the regeneration mode, specifically preferably depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

7. Dishwasher according to one of Claims 1 to 6, wherein the deionization unit (50) has a first cell (50a) and at least one further second cell (50b) which is connected in series or in parallel with the first cell (50a), and wherein the control device (10) is designed to selectively select and adjust an operating mode of the first cell (50a) and an operating mode of the at least one further, second cell (50b), specifically depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

8. Dishwasher according to Claim 7, wherein the control device (10) is designed to selectively interrupt a power supply to at least one of the cells (50a, 50b) of the deionization unit (50), specifically depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

9. Dishwasher according to Claim 7 or 8, wherein the control device (10) is designed to individually adjust a cycle time of the corresponding cell (50a, 50b) in the deionization mode and/or in the regeneration mode for each cell (50a, 50b) and/or to individually adjust the switchover frequency between the deionization mode and the regeneration mode for each cell (50a, 50b), specifically preferably depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

10. Dishwasher according to one of Claims 7 to 9, wherein the control device (10) is designed to selectively adjust at least one parameter which characterizes the operation of the first and/or the at least one further, second cell (50a, 50b), specifically depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

11. Dishwasher according to one of Claims 1 to 10, which further has a sensor device for detecting a parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or a parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

12. Dishwasher according to Claim 11, wherein the sensor device has at least one conductivity sensor.

13. Dishwasher according to one of Claims 1 to 12, wherein the control device (10) is further designed to adjust at least one parameter which characterizes the operation of the deionization unit (50) and, respectively, the operation of the at least one cell (50a, 50b) of the deionization unit (50) and/or an operating mode of the deionization unit (50) and, respectively, an operating mode of the at least one cell (50a, 50b) of the deionization unit (50), specifically depending on a treatment program which is selected for the dishwasher and/or depending on a treatment phase of the dishwasher.

14. Dishwasher according to one of Claims 1 to 13, wherein the control device (10) is further designed to adjust at least one parameter which characterizes the operation of the deionization unit (50) and, respectively, the operation of the at least one cell (50a, 50b) of the deionization unit (50) and/or an operating mode of the deionization unit (50) and, respectively, an operating mode of the at least one cell (50a, 50b) of the deionization unit (50), specifically depending on a type of washware which is treated or is to be treated in the dishwasher.

15. Method for operating a dishwasher according to one of Claims 1 to 14, wherein at least one parameter which characterizes the operation of the deionization unit (50) is adjusted, preferably in a regulating manner, depending on at least one parameter which characterizes the quality of the fresh water at the inlet (71) of the deionization unit (50) and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet (51) of the deionization unit (50).

16. A dishwasher for crockery or utensils, comprising: at least one controllable, capacitive deionization unit (50) with an inlet (71) for fresh water and an outlet (51) for demineralized water and a control device (10) which is associated at least with the deionization unit (50), wherein the control device (10) is configured to automatically adjust at least one operating parameter of the deionization unit (50) in response to (i) monitoring of at least one quality characteristic of the fresh water at the inlet (71) of the deionization unit (50) and/or (ii) monitoring of at least one quality characteristic of the demineralized water at the outlet (51) of the deionization unit (50).

17. The dishwasher according to Claim 1, wherein the dishwasher has a manually operable interface by means of which the at least one operating parameter can be adjusted by the operator of the dishwasher.

18. The dishwasher of Claim 1, wherein the control device (10) is configured to adjust (i) a level of an electrical voltage which is supplied to the deionization unit (50) and/or (ii) a polarity of an electrical voltage which is supplied to the deionization unit (50).

19. The dishwasher according to 18, wherein the deionization unit (50) has at least one cell (50a, 50b) which can be selectively operated in a deionization mode, in a regeneration mode or in a flush mode.

20. The dishwasher according to Claim 4, wherein the control device (10) is configured to select and adjust the operating mode of the at least one cell (50a, 50b) in response to changes in the at least one quality characteristic of the fresh water at the inlet (71) of the deionization unit (50) and/or in response to changes in the at least one quality characteristic of the demineralized water at the outlet (51) of the deionization unit (50).

Description:
DISHWASHER AND METHOD FOR OPERATING A DISHWASHER

Description

[0001] The invention relates to a dishwasher and, in particular, to a commercial dishwasher for crockery or utensils, which is in the form of a box-type dishwasher or in the form of a conveyor dishwasher. The invention also relates to a method for operating such a dishwasher.

[0002] Conveyor dishwashers are, in particular, flight-type warewashers or rack conveyor warewashers. In contrast to box-type dishwashers, where the washware to be cleaned remains stationary in one single treatment zone of the box-type dishwasher during cleaning, in the case of conveyor dishwashers the washware is conveyed through different treatment zones of the conveyor dishwasher.

[0003] A conveyor dishwasher conventionally comprises at least one pre-wash zone and at least one main wash zone which, as seen in the conveying direction of the washware, is arranged downstream of the pre-wash zone or, respectively, the pre-wash zones. As seen in the conveying direction, at least one rinse zone and at least one final rinse zone, which is connected downstream of the rinse zone, is arranged, as a rule, downstream of the main wash zone or, respectively, the main wash zones. After usually passing through an inlet tunnel, washware which is received either directly on the conveyor belt or washware which is held by means of baskets, accordingly runs through one or several pre-wash zones, one or several main wash zones, one or several rinse zones and one or several final rinse zones, a drying zone and an outlet section, as seen in the conveying direction.

[0004] The named wash zones of the conveyor dishwasher have in each case assigned thereto a treatment system which comprises a wash pump and a line system which is connected to the wash pump and by means of which wash liquid is supplied to the nozzle system or, respectively, to the nozzle of the nozzle system. The wash liquid or,

respectively, treatment liquid, which is supplied to the at least one wash nozzle of the nozzle system, is sprayed in the respective wash zones of the conveyor dishwashers onto the washware which is conveyed through the respective wash zones by a conveying device of the conveyor dishwasher. Each wash zone has associated therewith a tank into which the liquid sprayed by the wash nozzle is received and/or in which liquid is supplied for the nozzle system of the relevant treatment zones.

[0005] In the case of conveyor dishwashers which are disclosed conventionally in the prior art, final rinse liquid in the form of fresh water is sprayed onto the washware by means of the spray nozzles of the final rinse zone. At least a portion of the sprayed final rinse liquid is conveyed from zone to zone counter to the conveying direction of the washware by means of a cascade system.

[0006] The sprayed final rinse liquid is collected in a tank of the rinse zone, from which it is conveyed to the spray nozzles of the rinse zone by means of the wash pump of the wash system associated with the rinse zone. In the rinse zone, wash liquid is rinsed from the washware. The liquid which is produced in this connection flows into the wash tank of the at least one main wash zone which is connected upstream of the rinse zone as seen in the conveying direction of the washware. Here, the liquid is conventionally provided with a detergent and is sprayed onto the washware via the nozzles of the main wash zone by means of a pump system which is associated with the wash system of the main wash zone. From the wash tank of the main wash zone, the liquid then flows into the pre-wash tank of the pre-wash zone. The liquid in the pre-wash tank is sprayed onto the washware via the pre-wash nozzles of the pre-wash zone by way of a pump system which is associated with the wash system of the pre-wash zone in order to remove coarse contaminants from the washware.

[0007] Box-type dishwashers are dishwashers which are manually loadable and unloadable. Crockery basket pass-through dishwashers, which are also called hood-type warewashers or front loader warewashers, are included here. Front loaders can be undercounter machines and also topcounter machines or free standing front loaders.

[0008] A dishwasher realized as a box-type dishwasher conventionally has a treatment zone (treatment chamber) for cleaning the washware. A wash system, which is realized as a recirculation loop is arranged, as a rule, in said treatment zone. A wash tank, in which liquid from the treatment zone is able to flow back due to gravity, is conventionally arranged under the treatment chamber. Wash liquid, which is usually water to which detergent can be added, as necessary, is situated in the wash tank. [0009] The wash liquid which is situated in the wash tank can be conveyed by a wash pump via a line system to the at least one wash nozzle and can be sprayed through said at least one wash nozzle onto the washware to be cleaned in the treatment chamber.

[0010] In the case of dishwashers which are realized as box-type dishwashers, fresh water can be introduced into the treatment chamber, as a rule into the nozzle and line system of the treatment chamber, via a fresh water inlet. This is necessary, for example, at the start of the cleaning program in order to make a necessary quantity of recirculation water available. Following a cleaning program phase of the dishwasher realized as a box- type dishwasher, introduced fresh water can, however, also serve as final rinse water.

[0011] Before new fresh water is supplied for the final rinsing, the same quantity of wash liquid is, as a rule, pumped out of the wash tank into the building-side wastewater network.

[0012] It has already been disclosed that the quality of the water of the introduced water is a critical prerequisite for a perfect wash result. As the water to be introduced is usually removed from the local drinking water network, as a rule it does not have all the requirements for a water quality that is perfect as regards aspects of dishwashing. Among other things, the overall hardness of the water to be introduced, the chloride content, the concentration of heavy metals and the overall salt content are used in the assessment of the water quality.

[0013] Guidelines in the industry for the maximum chloride content to avoid pitting in the case of low-alloy cutlery handles are, for example, 50 mg/1 water.

[0014] In the case of heavy metals, approximately 0.1 mg iron and 0.05 mg manganese/1 water are deemed to be maximum values, as exceeding said limit values can result in the washware and the dishwasher discoloring.

[0015] Similar considerations apply to the overall salt content in the water to be introduced.

[0016] In order to maintain such limit values, it is known to use reverse osmosis systems in industrial dishwashers. The disadvantage of these types of conventional dishwashers with conventional systems for maintaining such water quality limit values is, in this connection, that they are high-maintenance and energy-intensive and produce a large quantity of water loss which can no longer be used for rinsing purposes. Conventional reverse osmosis systems thus require pumps at comparably high pressure and, as a result, at a high connected load such that the energy consumption increases significantly. In addition, the membrane filter systems of such reverse osmosis installations quickly become blocked, which drives up maintenance costs. Furthermore, the dishwasher is no longer available for the wash operation during the maintenance intervals, i.e. in particular during the times when the membrane filter systems are replaced.

[0017] The object underlying the present invention is to increase the flow capacity of the washware as well as the reliability of a dishwasher. In particular, a dishwasher as well as a method for operating a dishwasher are to be provided, by means of which the reliability of the dishwasher is increased and downtime is reduced, at the same time costs are reduced and at the same time energy and water consumption is decreased, limit values named above for water quality not being exceeded.

[0018] With regard to the dishwasher, the object underlying the invention is achieved by the subject matter of independent claim 1 and with regard to the method, by the subject matter of subordinate claim 15.

[0019] Accordingly proposed, in particular, is a dishwasher which is above all a commercial dishwasher for crockery or utensils, which is in the form of a box-type dishwasher or in the form of a conveyor dishwasher, wherein the dishwasher has at least one controllable, capacitive deionization unit with an inlet for fresh water and an outlet for demineralized water and a control device which is associated at least with the deionization unit. According to the invention, it is provided, in particular, that the control device is designed to preferably automatically, and in an even more preferred manner, selectively automatically adjust, preferably in a regulating manner, at least one parameter which characterizes the operation of the deionization unit, depending on at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet of the deionization unit.

[0020] The parameter which characterizes the quality of the fresh water at the inlet of the deionization unit or, respectively, the parameter which characterizes the quality of the demineralized water at the outlet of the deionization unit, is, in particular, the conductivity of the corresponding liquid which is detectable preferably by means of a corresponding sensor device. In said context, it is, in particular, conceivable for the sensor device to have at least one correspondingly realized and arranged conductivity sensor.

[0021] The parameter which characterizes the quality of the fresh water or, respectively, the quality of the demineralized water is preferably detected continuously or at predefined times and/or events by means of the sensor device.

[0022] However, the present invention is not restricted to embodiments where the conductivity value of the liquid provides the parameter which characterizes the quality of the liquid. It would also be conceivable in said context, for example, to draw a conclusion as to at least one parameter characterizing the quality of the liquid in a spectroscopic manner or within the framework of complexometric titration.

[0023] In particular, it is not absolutely necessary to measure (detect) the parameter characterizing the quality of the liquid directly; rather embodiments are also considered where the parameter characterizing the quality of the liquid is detected or, respectively, determined indirectly. Also, those embodiments where the parameter characterizing the quality of the liquid is input externally or, respectively, manually into the control device are also to be covered by the invention.

[0024] Over and above this, the term "outlet for demineralized water" used herein is not to be interpreted as restrictive. In this connection, this is, in particular, an outlet of the deionization unit, by means of which water which is demineralized in part in the deionization mode of the deionization unit is able to be output. In a corresponding regeneration mode or even in the non-connected state of the deionization unit, no demineralized water in the actual sense is consequently output via the outlet for

demineralized water. In this respect, the intended specification "for demineralized water" is not to be interpreted as restrictive.

[0025] Over and above this, the term "deionized water" used herein is to designate, in particular, also part-deionized water and/or demineralized, in particular part-demineralized water. Deionization or, respectively, mineralization of fresh water takes place in the deionization unit preferably by means of an ion exchange process, by means of which ions are at least partially removed from the fresh water treated in the deionization unit and/or calcium and magnesium are removed.

[0026] The deionization unit considered herein is realized, in particular, as a capacitive deionization unit which is designed to remove electrically charged particles or ions from the fresh water supplied to the deionization unit via the inlet thereof. In this case, the fresh water, serving as electrolyte or, respectively, as ion-containing liquid, is moved into a space between two oppositely charged electrodes of a capacitor. Corresponding to their polarity, the charged particles diffuse to one of the electrodes and form an electric double layer with the same. The deionization phase of the deionization unit, i.e. the "cleaning phase" of the fresh water which is to be treated in the deionization unit, lasts until the double layer is saturated and the voltage between the electrodes drops away mainly in the double layer and is no longer over the liquid-filled space.

[0027] For the following regeneration phase of the deionization unit, a solution called brine is moved into the space and the voltage between the electrodes is reset or even partially reversed. In this case, the ions of the double layer diffuse back into the brine. A certain volume of brine is generally used several times for the regeneration of the electrodes, the ion concentration in the brine increasing further each time.

[0028] A capacitive deionization unit of the type considered herein normally includes several units or cells which are similar in design to a super-capacitor or double layer capacitor. In dependence on the voltage drop at the electrodes, the maximum voltage with which a capacitor cell of this type can be loaded is between 1.3 and 3 volts for fresh water. Otherwise, there is the risk of water electrolysis being able to be started over the two double layers or redox reactions occurring at the electrodes.

[0029] The cells of the deionization unit can be connected in parallel electrically, hydrodynamically they are arranged serially or in parallel, i.e. a quantity of fresh water liquid to be treated can be divided into different part quantities or part volumes which are processed in parallel or can flow through several cells one after the other. Primarily, the active overall electrode surface is critical to the maximum throughput of liquid, i.e. to the output of the deionization device. Said active overall electrode surface is increased by using porous electrode coatings. [0030] According to a further development of the invention, the dishwasher has a manually operable interface by means of which the at least one parameter which characterizes the operation of the deionization unit can be adjusted by the operator of the dishwasher.

[0031] According to preferred embodiments of the present invention, the capacitive deionization unit or, respectively, at least one cell thereof, has a plate capacitor with a positive and a negative electrode, "positive" and "negative" referring to the operating mode of the capacitive deionization unit. Such capacitive deionization units are also designated as FTC units (Flow Through Capacitor Cell).

[0032] Conceivable in said context is that the positive and the negative electrodes are kept apart by a spacer in order to define a flow path in the space between them for the fresh water to be treated. During a deionization process or, respectively, demineralization process, that is to say when there is a positive electrical potential at the positive electrode and a negative electric potential at the negative electrode, water (permeate) flowing through between the capacitor plates is effectively demineralized or, respectively, deionized at least in part. As already indicated, during the demineralizing or, respectively, deionizing process minerals from the traversing water are kept back (retentate) in the region of the plates. In order to free the capacitive deionization unit after a successful demineralizing phase or, respectively, deionizing phase of concentrated retentate, according to embodiments of the present invention, the polarities of the capacitor plates of the capacitive deionization unit are reversed. In order to prevent a reversed concentration of minerals taking place, i.e. a concentration of the minerals on the respectively oppositely situated capacitor plates, an anion membrane is preferably provided at the positive electrode placed on the side of the traversed space. In a corresponding manner, a cation membrane is provided at the negative electrode on the side of the space.

[0033] Following the polarity reversal of the capacitor plates, the retentate, which has been generated during the deionization phase or, respectively, demineralization phase, is concentrated in the water (which stands still or only flows slowly) in the space between the capacitor plates during said regeneration phase of the capacitive deionization unit. Said concentrated retentate in the relatively small volume of water is then able to be flushed as wastewater out of the capacitor deionization unit. [0034] According to an aspect of the present invention, the control device of the dishwasher according to the invention, which is associated at least with the deionization unit, is designed to adjust the level of an electrical voltage which is supplied to the deionization unit and/or the polarity of an electrical voltage which is supplied to the deionization unit depending on the parameter which characterizes the quality of the fresh water at the inlet of the deionization unit and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet of the deionization unit. It is possible in this way, as necessary, to adapt the deionization effect of the deionization unit to the real case. If, for example, it is detected that the quality of the demineralized water at the outlet of the deionization unit is deteriorating, when, for example, the conductivity of the demineralized water at the outlet of the deionization unit increases, the level of the electrical voltage which is supplied to the deionization unit is increased preferably automatically according to the invention by means of the control device in order to increase the degree of deionizing or, respectively, the mineralizing of the deionization unit.

[0035] Apart from this, fluctuations also occur in the quality of the fresh water at the inlet of the deionization unit. Such fluctuations are, in particular, dependent on the location of the dishwasher; however, seasonal fluctuations in the quality of the fresh water also occur. The deionization unit being adjusted in a regulating manner according to the invention in dependence on the quality of the fresh water supplied ensures that the quality of the water ultimately used for washware treatment in the dishwasher always has a constantly high value.

[0036] As already indicated, it is preferred when the deionization unit has at least one cell which can be selectively operated in a deionization mode or in a regeneration mode.

According to a further aspect of the invention, it is provided in this context that the control device is designed to select and adjust the operating mode (deionization mode or regeneration mode) of the at least one cell of the deionization unit, depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet of the deionization unit. [0037] When the deionization unit has a first cell and at least one further second cell which is connected in series or preferably in parallel with the first cell, it is, in particular, advantageous when the control device is designed to selectively select and adjust the operating mode of the first cell and the operating mode of the at least one further, second cell, depending on at the least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet of the deionization unit. It is, for example, conceivable, in this connection, to operate the first cell in the regeneration mode whilst the at least one further second cell is operated in the deionization mode. Such phase-inverted operation is useful, in particular, when the cells of the deionization unit are arranged parallel to one another hydrodynamically at least in groups.

[0038] In said context, it is additionally advantageous when the individual cells of the deionization unit are controllable selectively by the control device, in particular as relates to the voltage supply to the respective cells of the deionization unit. The selective actuation of the individual cells of the deionization unit is preferably effected depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet of the deionization unit.

[0039] As an alternative to this or in addition to it, it is also advantageous, in particular, when the cycle time of the at least one cell in the deionization mode and/or in the regeneration mode or however, also the switchover frequency between the deionization mode and the regeneration mode is selected and adjusted by means of the control device. This is preferably effected individually for each cell of the deionization unit, and, in an even more preferred manner, depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet of the deionization unit.

[0040] The invention, however, is not limited to the regulating adjustment of the cycle time, of the switchover frequency and/or of the electric voltage. Rather, the invention, according to a further aspect, also relates to a dishwasher which has a control device which is designed to selectively adjust at least one parameter which characterizes the operation of the first and/or the at least one further, second cell, depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit and/or depending on the at least one parameter which characterizes the quality of the

demineralized water at the outlet of the deionization unit.

[0041] In a preferred realization of the solution according to the invention, the control device which is associated with at least the deionization unit is further designed to select and correspondingly adjust at least one parameter which characterizes the operation of the deionization unit and, respectively, the operation of the at least one cell of the deionization unit and/or an operating mode of the deionization unit and, respectively, an operating mode of the at least one cell of the deionization unit, in particular also depending on a treatment program which is selected for the dishwasher or depending on a treatment phase of the dishwasher (occurring at that moment or intended to occur shortly).

[0042] If, for example, the dishwasher is to be used for cleaning glasses or glass-like washware and a corresponding treatment program is selected for the dishwasher, the control device, which is associated with at least the deionization unit, adjusts the deionization unit in a preferred manner such that the quality of the demineralized water at the outlet of the deionization unit corresponds to the quality necessary for optimum glass cleaning or, respectively, glass washing. Said quality of the demineralized water is, as a rule, greater in comparison with the quality of demineralized water which is to be used to clean, for example, plastic material trays.

[0043] Consequently, by means of the solution according to the invention, the deionizing or, respectively, the mineralizing of the water which is used for washing and rinsing in the dishwasher can be adapted in an optimum manner to the respective facts and conditions.

[0044] Exemplary embodiments of the solution according to the invention are described in more detail below with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic representation of a dishwasher which is designed in the form of a conveyor dishwasher according to a first embodiment;

FIG. 2 shows a schematic representation of a dishwasher which is designed in the form of a conveyor dishwasher according to a second embodiment; FIG. 3 shows a schematic representation in cross section of a cell of a

capacitive deionization unit for use in a dishwasher according to the

embodiments, during a deionization operation;

FIG. 4: shows the cell of the capacitive deionization unit from FIG. 3 during a regeneration operation; and

FIG. 5 shows the cell of the capacitive deionization unit from FIG. 3 during a flush operation.

[0045] FIG. 1 shows a schematic longitudinal view of an example of a conveyor dishwasher 100 which is designed according to the teachings of the present invention. The conveyor dishwasher 100 according to the representation in FIG. 1 has a pre-wash zone 30, a main wash zone 31, a rinse zone 32, a final rinse zone 33 and a drying zone 34. After passing through an inlet tunnel 36a, the aforenamed zones are run through by the washware (not shown in FIG. 1) in the conveying direction T.

[0046] Washware received either directly on a conveyor belt 35 or washware held by means of baskets runs in the conveying direction T accordingly first of all through an inlet tunnel 36a, the pre-wash zone 30 which connects to said inlet tunnel, the main wash zone 31 which connects to said pre-wash zone, the rinse zone 32 which connects to said main wash zone, the final rinse zone 33 which connects to said rinse zone and the drying zone 34 which connects to said final rinse zone.

[0047] The treatment zones 30, 31, 32, 33 of the conveyor dishwasher 100 have associated therewith in each case a treatment system with a nozzle system (60, 61, 62, 63) each nozzle system having at least one nozzle for spraying treatment liquid onto the washware which is conveyed past. At least the pre-wash zone 30, the main wash zone 31 and the rinse zone 32 have associated therewith in each case a wash tank (80, 81, 82) in which sprayed wash liquid is received and/or wash liquid is supplied for the nozzle systems of the relevant treatment zones (30, 31, 32).

[0048] Pumps, which, via a line system which is connected thereto, supply the liquid from the wash tanks (80, 81, 82) to the respective nozzle systems 60, 61, 62 again at least in part, are provided for circulating the sprayed treatment liquid at least in the pre-wash zone 30, the main wash zone 31 and the rinse zone 32.

[0049] Additionally provided is a dishwasher control means, which is not shown in the drawings and, in the case of the embodiment of the invention realized as a conveyor dishwasher 100, serves, among other things, for controlling the respective wash pumps of the treatment systems in a suitable manner during a wash process in order to supply wash liquid to the nozzle systems 60, 61, 62 of the respective treatment systems at least at times via the associated line system.

[0050] In the case of the conveyor dishwasher 100 shown in FIG. 1, the nozzle system 63 of the final rinse zone 33 is supplied with final rinse liquid via a fresh water inlet 70, through which fresh water is pumped out of a buffer storage unit 53 by means of a rinse pump 43. The final rinse liquid is sprayed onto the washware, which is not shown in FIG. 1, inside the final rinse zone 33 by means of the nozzles of the nozzle system 63, which are arranged above and below the conveyor belt 35. As indicated in FIG. 1, the nozzle system 63 of the final rinse zone 33 can also have laterally arranged spray nozzles.

[0051] A portion of the final rinse liquid sprayed in the final rinse zone is conveyed from zone to zone counter to the conveying direction T of the washware by means of a cascade system. The final rinse liquid sprayed in the final rinse zone 33 is collected in the tank (rinse tank 82) of the rinse zone 32, from which it is conveyed by means of the wash pump which is associated with the wash system of the rinse zone 32 to the nozzle system 62, i.e. to the rinse nozzles 62 of the rinse zone 32. Wash liquid is rinsed from the washware in the rinse zone 32.

[0052] The liquid arising in this connection flows into the main wash tank 81 of the main wash zone 31, is usually provided with a detergent and is sprayed onto the washware by means of a wash pump which is associated with the wash system 61 of the main wash zone 31 via the wash nozzles of the wash system which is associated with the main wash zone 31.

[0053] From the wash tank 81 of the main wash zone 31, the wash liquid then flows into the pre-wash tank 80 of the pre-wash zone 30. The wash liquid collected in the pre-wash tank 80 is sprayed onto the washware in the pre-wash zone 30 by means of a wash pump which is associated with the wash system 60 of the pre-wash zone 30 by means of the pre- wash nozzles of the nozzle system 60 which is associated with the pre-wash zone 30 in order to remove coarse contaminants from the washware.

[0054] Provided in the case of the embodiment shown in FIG. 1 is a fresh water system, which has a capacitive deionization unit 50, which is connected between a water supply 71 and the fresh water inlet 70, is designed to be controllable and, in turn, once again has two cells 50a, 50b.

[0055] The capacitive deionization unit 50 is designed, in this connection, in such a manner that it (or, respectively, its cells 50a, 50b) is (or, respectively, are) able to be moved in a controllable manner into a deionization mode, a regeneration mode and a flush mode. Said individual operating modes will be explained in more detail further below in conjunction with figures 3 to 5.

[0056] During the deionization operation of the capacitive deionization unit 50 (or, respectively, of the cells 50a, 50b), deionized fresh water is transferred via an outlet 51 of the capacitive deionization unit 50 into the buffer storage unit 53. From here, it can be supplied to the treatment zones, in particular to the nozzle system 63 of the final rinse zone 33, by means of the final rinse pump 43 (which is also designed in a controllable manner) via the fresh water inlet 70.

[0057] During a flush mode of the capacitive deionization unit 50, the concentrated retentate is able to be removed from the capacitive deionization unit 50 or, respectively, from the cells 50a, 50b thereof via a retentate outlet 52.

[0058] A control device 10, which can be designed as a separate control device 10 or, respectively, as a control device 10 which is integrated with the dishwasher control means, is provided in the case of the first embodiment shown in FIG. 1.

[0059] The control device is designed (e.g., programmed or otherwise configured) in the first embodiment shown in FIG. 1 for the purpose of modifying the operating mode of the cells 50a, 50b of the capacitive deionization unit 50 to the effect that it is possible to switch over between the deionization mode of the capacitive deionization unit 50, the regeneration mode and the flush mode. Such a switchover of the operating mode of the capacitive deionization unit 50 is effected in this connection in dependence on at least one operating variable.

[0060] As shown in the first exemplary embodiment according to FIG. 1 by way of the conveyor dishwasher 100, the control device 10 receives a conductivity signal of the conductivity of the liquid in the buffer storage unit 53 via a conductivity sensor 11, a fill level inside the buffer storage unit 53 by means of a fill lever sensor 12 and information concerning detected washware at the inlet 35 of the conveyor dishwasher 100 by means of an input identification device 20. It is additionally conceivable for the control device 10 to receive information on the status, for example the retentate concentration at the electrodes or, respectively, at the membranes of the cells 50a, 50b of the capacitive deionization unit 50.

[0061] By way of one or several of said operating variables, that is to say by way of information on the type of the washware detected by means of the input identification device 20, of conductivity and consequently of an ion concentration in the buffer storage unit 53, of a fill level of the buffer storage unit 53 and/or of information on the retentate saturation status of the capacitive deionization unit 50, the control device 10 performs a switchover between the individual operating modes of the capacitive deionization unit 50.

[0062] In this connection, it is in particular conceivable for the two cells 50a, 50b of the capacitive deionization unit 50 to be operated in an alternate manner in each case in their respective deionization mode, their respective regeneration mode and their respective flush mode.

[0063] In the case of operating variables which change over time, a renewed switchover can be effected at a subsequent time between the individual operating modes of the capacitive deionization unit 50.

[0064] With reference to the fill level, which is detected by means of the fill level sensor 12, inside the buffer storage unit 53, according to the first embodiment shown in FIG. 1, the capacitive deionization unit 50, or, respectively, at least one cell 50a, 50b of the capacitive deionization unit 50, can be operated in its deionization mode when the fill level inside the buffer storage unit 53 has dropped below a fixed or fixable threshold value. [0065] In contrast to this, where the fresh water fill level inside the buffer storage unit 53 is sufficient, i.e. when the fill level sensor 12 detects that a fixed or fixable upper limit value for the fresh water fill level inside the buffer storage unit 53 has been exceeded, it is provided to operate the capacitive deionization unit 50 or, respectively, at least one of the cells 50a, 50b of the capacitive deionization unit 50 in its/their regeneration mode or in its/their flush mode.

[0066] As a result, it is possible to delay the regeneration phase or, respectively, the flush phase, i.e. that is to say the phases during which no deionized fresh water is allowed out of the outlet 51 into the buffer storage unit 53, in such a manner that said (non-productive) operating times of the capacitive deionization unit 50 are moved to periods in which the buffer storage unit 53 is sufficiently filled. As a result, once again improved, continuous operation of the conveyor dishwasher 100 according to the first embodiment in FIG. 1 without unwanted downtimes is ensured.

[0067] At the same time, as a result of each of the cells 50a, 50b of the capacitive deionization unit 50 being able to be regenerated in a simple manner as a result of actuation and prepared for the next chronological phase of deionization operation, the maintenance costs are reduced and reliability is increased.

[0068] In a similar manner, as an alternative to or in addition to the fill level

measurement, a measurement of the conductivity can also be carried out inside the buffer storage unit 53 by means of the conductivity sensor 11 and the measured value can be transmitted to the control device 10. Such a conductivity measurement via a concentration sensor which is designed as a conductivity sensor 11 provides a measure for the ion concentration of the supplied fresh water inside the buffer storage unit 53. Accordingly, it is possible to adjust a target ion concentration of the supplied fresh water which is output into the buffer storage unit 53 as a result of corresponding actuation of the capacitive deionization unit 50 or, respectively, of the cells 50a, 50b. In particular, combined with washware type identification by means of the input identification device 20, such a desired ion concentration (max. ion concentration) of the supplied fresh water which is output into the buffer storage unit 53, is simple to obtain. [0069] In said context, it is, for example, conceivable that when cutlery is detected at the inlet 35 of the conveyor dishwasher 100 by means of the input identification device 20, a maximum target ion concentration, which is set at a conductivity of the prepared fresh water inside the buffer storage unit 54 of approximately 80 μ8/αη, is automatically provided.

[0070] Correspondingly, an ion concentration, which is set at a measured conductivity of approximately 100μ8/αη, with reference to the supplied fresh water inside the buffer storage means 53, is sensible in the case of washware which is detected as glassware. It is possible to give other concentrations for other types of washware or, respectively, to give conductivities which are directly linked to the concentrations.

[0071] As, therefore, in particular in the case of washware which is detected as glasses, a higher ion concentration is able to be tolerated than, for example, washware which is detected as cutlery, it is then possible, e.g., for the control device 10 to operate the capacitive deionization unit further also for a period in which the quality of the supplied fresh water, which is allowed out into the buffer storage unit 53 via the permeate outlet 51, has already reduced. This type of reduction in quality is produced, in particular, when the electrodes of the capacitive deionization unit 50 are saturated with retained materials (retentate). As, in this case, the quality of the fresh water output for the detected type of washware (in this case: glasses), which is determined by the conductivity sensor 11, continues to be sufficient, the regeneration phase and flush phase of the cells 50a, 50b of the capacitive deionization unit 50 is selected by the control device 10 for a later, more favorable time, for example when the buffer storage unit 53 is sufficiently filled.

[0072] In addition, a controllable valve (V2, V4, V5) is provided in each case in the water supply 71, upstream of the outlet 51 and upstream of the retentate outlet 52, it also being possible to control the valves V2, V4, V5 by means of the control device 10. Said valves V2, V4, V5 serve for the purpose of supporting the switchover of the capacitive deionization unit 50 or, respectively, of the cells 50a, 50b thereof, between their respective deionization mode and in the regeneration mode or, respectively, the flush mode.

[0073] As shown in FIG. 2, it is also conceivable as an alternative to the embodiment shown in FIG. 1, to realize the dishwasher as a box-type dishwasher 200. The box-type dishwasher 200 has one single treatment zone 201 (treatment chamber) in which a nozzle system 202, consisting of upper and lower nozzles, is realized for spraying the washware (not shown in FIG. 2) with treatment liquid.

[0074] In addition, such a dishwasher which is realized as a box-type dishwasher 200 has a program control device (not shown in FIG. 2) for controlling at least one wash program.

[0075] The treatment chamber (treatment zone 201) is designed to be closable by a door (not shown) or a hood (not shown) and serves for receiving washware to be cleaned such as, for example, crockery, cutlery, pots, pans and/or trays.

[0076] Beneath the treatment zone 201 of the box-type dishwasher 200 there is a wash tank 203 for receiving sprayed liquid from the treatment zone 201. A wash pump is provided for conveying wash liquid out of the wash tank through a wash liquid line system to the nozzle system 202 of the box-type dishwasher 200. The wash liquid, which is sprayed inside the treatment zone 201, flows back into the wash tank 203 on account of gravity. In this case, the wash tank 203, the wash pump, the wash liquid line system and the nozzle system 202 together with the treatment zone 201 form a wash liquid circuit.

[0077] A fresh water pump 43, which is connected on the input side to a buffer storage unit 53, is provided for supplying fresh water into a fresh water inlet 70, which, in turn, introduces water into the nozzle system 202 or, respectively, into the treatment zone 201 of the box-type dishwasher 200. Analogously to the first embodiment which was described in conjunction with FIG. 1, a dishwasher, which is realized as a box-type dishwasher 200 according to the embodiment shown in FIG. 2, has, in turn, a fresh water system which is formed by, among other things, a capacitive deionization unit which is connected on the input side to a water supply 71 and on the output side, with the interposition of the buffer storage unit 53 and the fresh water pump 43, to the fresh water inlet 70.

[0078] Once again, it is also possible to use a capacitive deionization unit 50 which has several cells 50a, 50b in the case of a box-type dishwasher 200. Also provided in this case is a control device 10, which is designed for the purpose of controlling the capacitive deionization unit 50 or, respectively, the cells 50a, 50b thereof independently of an operating variable of the dishwasher, in particular between a deionization mode, a regeneration mode and a flush mode of the capacitive deionization unit 50 or, respectively, of the cells 50a, 50b thereof.

[0079] In the case of the dishwasher which is realized as a box-type dishwasher 200 according to the second embodiment shown in FIG. 2, in particular a wash program of the dishwasher, such as, e.g., a glass wash program, a cutlery wash program or a pots wash program, is considered as one of the operating variables on which a switchover of the operating mode of the capacitive deionization unit by means of the control device is made dependent.

[0080] In particular when, additionally, for example, a conductivity sensor 11 is once again provided which supplies conclusions as to the ion concentration inside the buffer storage unit by means of a measurement of the conductivity, it is advantageous to match the individual operating modes of the capacitive deionization unit 50 to the requirements of the selected wash program. Thus, for example, when a cutlery or a glass wash program is selected, the demineralizing program step (that is the time period) during which the capacitive deionization unit 50 or, respectively, at least one of its cells 50a, 50b, is operated in the deionization mode can be extended in order to obtain a smaller ion concentration of the output permeate as a result.

[0081] When a cutlery program is selected, an upper limit value for the conductivity of the supplied freshwater inside the buffer storage unit 53, which supplies conclusions as to the ion concentration, can consequently be selected as approximately 80 μ8/αη. When, apart from this, a glass wash program is selected, said upper limit value can be

approximately 100 μ8/αη.

[0082] In addition, analogously to the first embodiment which was described in conjunction with FIG. 1, it is once again possible to use a fill level sensor at the buffer storage unit 53 which provides an alternative or an additional operating variable of the dishwasher, in dependence on which the control device controls the operating modes of the capacitive deionization unit 50 or, respectively, of the cells 50a, 50b thereof, in a corresponding manner.

[0083] In other words, the necessary quantity of fresh water and the selected wash program determine the time limits and the quality of the supplied permeate of the capacitive deionization unit (FTC unit) as a result of influencing the start or end points or, respectively, the time taken for the individual operating modes of the capacitive deionization unit (deionizing/regenerating, flushing).

[0084] Said operating modes of the capacitive deionization unit 50 are explained in more detail below with reference to the representations in figures 3 to 5.

[0085] FIG. 3 shows a schematic sectional view of a cell 50a, 50b of a capacitive deionization unit 50 which has a positive electrode 54a and a negative electrode 54b. It must be pointed out in this context that the expressions "positive" and "negative" provide the polarity of said electrodes 54a, 54b during a deionization operation. As described further below, switching the polarity of the electrodes 54a, 54b is also provided in other operating modes.

[0086] A flow path for traversing water is provided between the positive electrode 54a and the negative electrode 54b, the flow direction of the water is indicated by way of the reference 57. An anion membrane 55 is provided in the vicinity of the positive electrode 54a, placed toward the flow path; in an analogous manner, a cation membrane 56 is provided in the vicinity of the negative electrode 54b. The anion membrane 55 is only permeable to anions, whereas the cation membrane 56 is analogously only passable by cations.

[0087] In the deionization operation shown in FIG. 3, a positive voltage is therefore placed at the positive electrode 54a and a negative voltage is placed at the negative electrode 54b. Water traversing the cell 50a, 50b is then deionized in a deionization operation, as shown in FIG. 3, as a result of anions 58 being attracted inside the water flow in the direction of the positive electrode 54a and cation 59 in the direction of the negative electrode 54b. Water leaving the cell consequently only still has a very small ion concentration.

[0088] FIG. 4 shows a regeneration operation of the cells 50a, 50b from FIG. 3. As shown in FIG. 4, a negative electric voltage is placed on the positive electrode 54a in the regeneration mode; analogously to this, a positive voltage is placed on the negative electrode 54b in said regeneration mode. [0089] During the regeneration operation, the water inside the cell normally stands still such that the minerals which have accumulated on the electrodes during the deionization operation of the cell 50a, 50b are concentrated in the water. Care must be taken in this connection to ensure that the anion membrane 55 and the cation membrane 56 ensure that no enrichment of the oppositely charged ions 55, 59 takes place at the electrodes 54a, 54b.

[0090] During a flush operation shown in FIG. 5, no electric voltage is then placed on the positive electrode 54a or the negative electrode 54b. The retentate, concentrated inside the cell, in the water can then be flushed out of the cell 50a, 50b in the direction of flow 57.

[0091] The dishwasher 100, 200 according to the invention is also distinguished, in particular, in that the control device 10 is designed to adjust, preferably in a regulating manner, at least one parameter which characterizes the operation of the deionization unit 50, depending on at least one parameter which characterizes the quality of the fresh water at the inlet 71 of the deionization unit 50 and/or depending on at least one parameter which characterizes the quality of the demineralized water at the outlet 51 of the deionization unit 50.

[0092] The parameter which characterizes the quality of the fresh water at the inlet of the deionization unit 50 or, respectively, the parameter which characterizes the quality of the demineralized water at the outlet 51 of the deionization unit 50 is, in particular, the conductivity of the corresponding liquid which is preferably detectable by means of a corresponding sensor device. In said context, it is in particular conceivable for the sensor device to have at least one correspondingly designed and arranged conductivity sensor.

[0093] The deionization unit 50 considered herein is realized, in particular, as a capacitive deionization unit 50 which is designed to remove electrically charged particles or ions from the fresh water supplied to the deionization unit 50 via the inlet thereof. In this case, the fresh water, serving as electrolyte or, respectively, as ion-containing liquid, is moved into a space between two oppositely charged electrodes of a capacitor.

Corresponding to their polarity, the charged particles diffuse to one of the electrodes and form an electric double layer with the same. The deionization phase of the deionization unit 50, i.e. the "cleaning phase" of the fresh water which is to be treated in the deionization unit 50 lasts until the double layer is saturated and the voltage between the electrodes drops away mainly in the double layer and is no longer over the liquid-filled space.

[0094] A capacitive deionization unit 50 of the type considered herein normally includes several units or cells 50a, 50b which are similar in design to a super-capacitor or double layer capacitor. The cells 50a, 50b of the deionization unit 50 can be connected in parallel electrically, hydrodynamically they are arranged serially or in parallel, i.e. a quantity of fresh water liquid to be treated can be divided into different part quantities or part volumes which are processed in parallel or can flow through several cells 50a, 50b one after the other.

[0095] According to an aspect of the present invention, the control device 10 of the dishwasher 100, 200 according to the invention, which is associated at least with the deionization unit 50, is designed to adjust the level of an electrical voltage which is supplied to the deionization unit 50 and/or the polarity of an electrical voltage which is supplied to the deionization unit 50 depending on the parameter which characterizes the quality of the fresh water at the inlet of the deionization unit 50 and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet 51 of the deionization unit 50. It is possible in this way, as necessary, to adapt the deionization effect of the deionization unit 50 to the real case. If, for example, it is detected that the quality of the demineralized water at the outlet 51 of the deionization unit 50 is deteriorating, as, for example, the conductivity of the demineralized water at the outlet 51 of the deionization unit 50 increases, the level of the electrical voltage which is supplied to the deionization unit 50 is increased preferably automatically according to the invention by means of the control device 10 in order to increase the degree of deionizing or,

respectively, the mineralizing of the deionization unit 50.

[0096] Apart from this, fluctuations also occur in the quality of the fresh water at the inlet of the deionization unit 50. Such fluctuations are, in particular, dependent on the location of the dishwasher 100, 200; however, seasonal fluctuations in the quality of the fresh water also occur. The deionization unit 50 being adjusted in a regulating manner according to the invention in dependence on the quality of the fresh water supplied ensures that the quality of the water ultimately used for washware treatment in the dishwasher 100, 200 always has a constantly high value. [0097] As already indicated, it is preferred when the deionization unit 50 has at least one cell 50a, 50b which can be selectively operated in a deionization mode or in a regeneration mode. According to a further aspect of the invention, it is provided in this context that the control device 10 is designed to select and adjust the operating mode (deionization mode or regeneration mode) of the at least one cell of the deionization unit 50, depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit 50 and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet 51 of the deionization unit 50.

[0098] When the deionization unit 50 has a first cell 50a and at least one further second cell 50b which is connected in series or preferably in parallel with the first cell 50a, it is, in particular, advantageous when the control device 10 is designed to selectively select and adjust the operating mode of the first cell 50a and the operating mode of the at least one further, second cell 50b, depending on at the least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit 50 and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet 51 of the deionization unit 50. It is, for example, conceivable, in this connection, to operate the first cell 50a in the regeneration mode or flush mode whilst the at least one further second cell 50b is operated in the deionization mode. Such phase-inverted operation is useful, in particular, when the cells 50a, 50b of the deionization unit 50 are arranged parallel to one another hydrodynamically at least in groups.

[0099] In said context, it is additionally advantageous when the individual cells 50a, 50b of the deionization unit 50 are controllable selectively by the control device 10, in particular as relates to the voltage supply to the respective cells 50a, 50b of the deionization unit 50. The selective actuation of the individual cells 50a, 50b of the deionization unit 50 is preferably effected depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit 50 and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet 51 of the deionization unit 50.

[0100] As an alternative to this or in addition to it, it is also advantageous, in particular, when the cycle time of the at least one cell 50a, 50b in the deionization mode and/or in the regeneration mode or however, also the switchover frequency between the deionization mode and the regeneration mode, is selected and adjusted by means of the control device 10. This is preferably effected individually for each cell 50a, 50b of the deionization unit 50, and in an even more preferred manner, depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit 50 and/or depending on the at least one parameter which characterizes the quality of the

demineralized water at the outlet 51 of the deionization unit 50.

[0101] The invention, however, is not limited to the regulating adjustment of the cycle time, of the switchover frequency and/or of the electric voltage. Rather, the invention, according to a further aspect, also relates to a dishwasher 100, 200 which has a control device 10 which is designed to selectively adjust at least one parameter which characterizes the operation of the first and/or the at least one further, second cell 50a, 50b of the deionization unit 50, depending on the at least one parameter which characterizes the quality of the fresh water at the inlet of the deionization unit 50 and/or depending on the at least one parameter which characterizes the quality of the demineralized water at the outlet 51 of the deionization unit 50.

[0102] In a preferred realization of the solution according to the invention, the control device 10, which is associated with at least the deionization unit 50, is further designed to select and correspondingly adjust at least one parameter which characterizes the operation of the deionization unit 50 and, respectively, the operation of the at least one cell of the deionization unit 50 and/or an operating mode of the deionization unit 50 and, respectively, of at least one cell of the deionization unit 50, in particular also depending on a treatment program which is selected for the dishwasher 100, 200 or depending on a treatment phase of the dishwasher 100, 200 (occurring at that moment or intended to occur shortly).

[0103] If, for example, the dishwasher 100, 200 is to be used for cleaning glasses or glass-like washware and a corresponding treatment program is selected for the dishwasher 100, 200, the control device 10, which is associated with the at least one deionization unit 50, adjusts the deionization unit 50 in a preferred manner such that the quality of the demineralized water at the outlet 51 of the deionization unit 50 corresponds to the quality necessary for optimum glass cleaning or, respectively, glass washing. Said quality of the demineralized water is, as a rule, greater in comparison with the quality of demineralized water which is to be used to clean, for example, plastic material trays. [0104] At this point, it must be pointed out that all the above-described parts, in particular the details shown in the drawings, are claimed as fundamental to the invention when viewed on their own and in any combination. Modifications hereto are familiar to the person skilled in the art.

List of references

Control device

Conductivity sensor

Fill level sensor

Input identification device

Pre-wash zone

Main wash zone

Rinse zone

Final rinse zone

Drying zone

Conveying device

Inlet

a Inlet tunnel

Partition curtain

Heat recovery device

Blower

Main line system

Hot water heater

Bypass line

Final rinse pump, fresh water pump

Capacitive deionization unit

a First cell of the capacitive deionization unitb Second cell of the capacitive deionization unit

Outlet

Retentate outlet

Buffer storage unit

a Positive electrode

b Negative electrode

Anion membrane

Cation membrane

Direction of flow Anion

Cation

Pre-wash nozzles

Main wash nozzles

Rinse nozzles

Final rinse nozzles

Fresh water inlet

Water supply

Pre-wash tank

Main wash tank

Rinse tank

Conveyor dishwasher

Box -type dishwasher

Treatment zone of the box-type dishwasher

Nozzle system of the box-type dishwasher

Wash tank of the box-type dishwasher

Conveying direction