Method for operating a dishwasher, and dishwasher

Abstract

A method is provided for operating a dishwasher (1) in the form of a batch dishwasher, which has a treatment chamber (2) for accommodating washware to be cleaned. Provision is made, during an adsorption phase, for air to be conducted out of the treatment chamber (2) through a sorption unit (41), which contains a reversibly dehydratable dry material, in such a way that the dry material absorbs moisture from the air stream, wherein the air is then returned to the treatment chamber (2). Provision is further made, during a desorption phase, for the dry material of the sorption unit (41) to be heated in such a way that moisture is desorbed from the dry material as steam. During the desorption phase, the sorption unit (41) is subjected to forced ventilation only to such an extent that recondensation of desorbed steam in the sorption unit (41) itself is effectively prevented.

Claims

1. A method for operating a dishwasher, which dishwasher has a treatment chamber for accommodating washware which is to be cleaned, wherein the method comprises the following method steps: i) during an adsorption phase, air is conducted out of the treatment chamber through a sorption unit, which contains a reversibly dehydratable dry material, in such a way that the dry material absorbs moisture from the air stream, wherein the air is then returned to the treatment chamber; and ii) during a desorption phase, the dry material of the sorption unit is heated in such a way that moisture is desorbed from the dry material as steam, wherein, during the desorption phase, the sorption unit is subjected to forced ventilation only to such an extent that recondensation of desorbed steam in the sorption unit itself is effectively prevented; wherein the desorption phase takes place within a time period of from 20 to 150 seconds in total; wherein, for forced ventilation of the sorption unit, a fan is actuated in such a way that a volumetric flow rate of air which is forced through the dry material during the desorption phase is in a range of between 0.05 and 200 m.sup.3/h.

2. The method as claimed in claim 1, wherein a total of at least 10 litres of air is blown through the sorption unit during the desorption phase.

3. The method as claimed in claim 1, wherein, during the desorption phase, the sorption unit is subjected to forced ventilation in such a way that moisture which is desorbed from the dry material is discharged from the sorption unit as steam such that recondensation in the sorption unit is specifically effectively prevented.

4. The method as claimed in claim 1, wherein the air is continuously or intermittently blown through the sorption unit by a fan during the desorption phase.

5. The method as claimed in claim 4, wherein the temperature of the heated dry material is measured continuously or at predefined times or in the case of predefined events in the sorption unit during the desorption phase, and wherein the output capacity of the fan is controlled as a function of the measured temperature of the heated dry material in such a way that the dry material assumes a temperature of less than 300 C.

6. The method as claimed in claim 4, wherein the temperature of the air which is forced through the heated dry material is measured continuously or at predefined times or in the case of predefined events during the desorption phase, and wherein the output capacity of the fan is controlled as a function of the measured temperature of the air which is forced through the heated dry material in such a way that the air which is forced through the dry material assumes a temperature of less than 200 C.

7. The method as claimed in claim 1, wherein the temperature of the heated dry material is measured continuously or at predefined times or in the case of predefined events in the sorption unit during the desorption phase, and wherein the heating power of a heating unit which is arranged in the sorption unit is controlled as a function of the measured temperature of the heated dry material in such a way that the dry material assumes a temperature of less than 300 C. in the desorption phase.

8. The method as claimed in claim 1, wherein a total of 60 to 1000 kJ of thermal energy is supplied to the dry material during the desorption phase.

9. The method as claimed in claim 1, wherein the thermal energy is supplied by a heating power of a total of 3 to 7 kW during the desorption phase.

10. The method as claimed in claim 1, wherein the desorption phase is subdivided with respect to time into an initial first time period and a subsequent second time period, and wherein a fan is actuated in such a way that a quantity of air which is forced through the dry material during the first time period per unit time is lower than a quantity of air which is forced through the dry material during the subsequent second time period per unit time.

11. The method as claimed in claim 1, wherein the desorption phase is subdivided with respect to time into an initial heating phase, during which thermal energy is supplied to the dry material with the aid of a heating device at the same time as forced ventilation, and into a subsequent follow-up phase, during which only forced ventilation takes place and no thermal energy is supplied to the dry material by the heating device.

12. The method as claimed in claim 1, wherein the method also comprises the following program-controlled method steps which are to be executed one after the other: a) during a wash phase, wash liquid is sprayed into the treatment chamber from a tank with the aid of a wash pump by means of a wash line system through wash nozzles, wherein at least some of the sprayed wash liquid flows back from the treatment chamber into the tank due to the force of gravity; and b) during a final-rinse phase, final-rinse fluid is conducted into the treatment chamber, wherein method step ii) takes place at least partly during the wash phase and/or at least partly during the final-rinse phase.

13. The method as claimed in claim 12, wherein method step i) is carried out at the same time as or so as to overlap, with respect to time, with a drying phase which takes place following the final-rinse phase.

14. The method as claimed in claim 12, wherein method step a) lasts for a total of 5 seconds to 360 seconds.

15. A batch dishwasher comprising: a treatment chamber, into which washware can be manually inserted and from which washware can be manually removed; a tank, into which liquid can flow off from the treatment chamber due to the force of gravity; a wash system having a wash pump and a wash line system for conveying wash liquid out of the tank during a wash phase and for spraying the wash liquid through wash nozzles in the treatment chamber; a fresh-water final-rinse system having at least one final-rinse pump and at least one final-rinse line system for conveying final-rinse liquid out of a fresh-water supply device during a fresh-water final-rinse phase and for spraying the final-rinse liquid through final-rinse nozzles in the treatment chamber; a drying device for continuously drawing moisture, or drawing moisture as required, from drying air which circulates in the treatment chamber, wherein the drying device has at least one sorption unit, which contains a reversibly dehydratable dry material, and also at least one fan for forming an air circuit as required in such a way that air is conducted through the sorption unit and then supplied to the treatment chamber; and a control device for carrying out the the following steps: (i) performing an adsorption phase in which air is conducted out of the treatment chamber through the sorption unit so that the dry material absorbs moisture from the air and the air is then returned to the chamber; and (ii) performing a desorption phase in which the dry material of the sorption unit is heated such that moisture is desorbed from the dry material and returned to the treatment chamber; wherein the control device is configured to control the sorption unit such that the desorption phase takes place within a time period of from 20 to 150 seconds in total and, for forced ventilation of the sorption unit, the fan is actuated in such a way that a volumetric flow rate of air which is forced through the dry material during the desorption phase is in a range of between 0.05 and 200 m.sup.3/h.

16. The dishwasher as claimed in claim 15, wherein the reversibly dehydratable dry material contains 0.3 to 3.0 kg of zeolite-containing material in the form of granules having a particle diameter of 0.5 to 10.0 mm.

17. The dishwasher as claimed in claim 15, wherein the drying device also has a heating unit for heating the reversibly dehydratable dry material as required, wherein the heating unit has a large number of heating elements which are preferably arranged at uniform distances within the reversibly dehydratable dry material.

18. The dishwasher as claimed in claim 17, wherein the drying device also has a heat exchanger unit which is connected to the sorption unit in such a way that, when an air circuit is formed, at least some of the air stream which is routed through the sorption unit also passes the heat exchanger unit.

19. A method for operating a dishwasher, which dishwasher has a treatment chamber for accommodating washware which is to be cleaned, wherein the method comprises the following method steps: i) during an adsorption phase, air is conducted out of the treatment chamber through a sorption unit, which contains a reversibly dehydratable dry material, in such a way that the dry material absorbs moisture from the air stream, wherein the air is then returned to the treatment chamber; and ii) during a desorption phase, the dry material of the sorption unit is heated in such a way that moisture is desorbed from the dry material as steam, wherein, during the desorption phase, the sorption unit is subjected to forced ventilation to such an extent that recondensation of desorbed steam in the sorption unit itself is effectively prevented; wherein operation of a fan during the desorption face, for the purpose of forced ventilation, is subdivided with respect to time into an initial first time period and a subsequent second time period, and wherein the fan is actuated in such a way that a quantity of air which is forced through the dry material during the first time period per unit time is lower than a quantity of air which is forced through the dry material during the subsequent second time period per unit time.

20. The method of claim 19, wherein heating of the dry material during the desorption phase is subdivided with respect to time into an initial heating phase, during which thermal energy is supplied to the dry material with the aid of a heating device at the same time as forced ventilation, and into a subsequent follow-up phase, during which only forced ventilation takes place and no thermal energy is supplied to the dry material by the heating device.

Description

(1) Exemplary embodiments of the solution according to the invention will be described in more detail below with reference to the accompanying drawings, in which:

(2) FIG. 1 shows schematically a dishwasher, in particular a commercial dishwasher, in the form of a batch dishwasher according to a first embodiment of the invention;

(3) FIG. 2 shows schematically a dishwasher, in particular a commercial dishwasher, in the form of a batch dishwasher according to a second embodiment of the invention;

(4) FIG. 3 shows schematically a first embodiment of a drying unit of the dishwasher according to the invention; and

(5) FIG. 4 shows schematically a second embodiment of a drying unit for a dishwasher according to the invention.

(6) The invention relates to commercial dishwashers, in particular crockery or utensil washers, in the form of a batch dishwasher. They customarily contain program control devices for controlling at least one cleaning program, and a treatment chamber 2, which can be closed by a door (not shown) or a hood (not shown), in a machine housing for accommodating washware (not shown) to be cleaned, such as, for example, crockery, silverware, pots, pans and trays.

(7) A wash tank 12 for accommodating sprayed liquid from the treatment chamber 2 is located below the treatment chamber 2. A wash pump 13 is provided for conveying wash liquid out of the wash tank 12, through a wash liquid line system 16, to wash nozzles 11a, 11b, which are directed, in the treatment chamber 2, onto the region of the washwear to be cleaned and which spray the wash liquid onto the washwear to be cleaned. The sprayed wash liquid returns to the wash tank 12 due to the force of gravity. The wash tank 12, the wash pump 13, the wash liquid system 16 and the wash nozzles 11, together with the treatment chamber 2, thereby form a wash liquid circuit. The wash liquid line system 16 connects the pressure side of the wash pump 13 to the wash nozzles 11a, 11b.

(8) Also provided is a final-rinse system for conveying final-rinse liquid, by means of a final-rinse pump 14, through a final-rinse line system 17 to final-rinse nozzles 15a, 15b, which are directed, in the treatment chamber 2, onto the region of the washwear to be cleaned. The sprayed final-rinse liquid returns from the treatment chamber 2 into the wash tank 12 due to the force of gravity. The final-rinse liquid system 17 connects the pressure side of the final-rinse pump 14 to the final-rinse nozzles 15a, 15b.

(9) It is possible for the wash nozzles 11a, 11b and the final-rinse nozzles 15a, 15b to be arranged within the treatment chamber in the regions above and/or below and, if desired, also to the sides of the washwear region, and to be directed in each case toward the region in which the washwear is positioned.

(10) It is preferable for a multiplicity of wash nozzles 11a to be provided on at least one upper wash arm, for a multiplicity of wash nozzles 11b to be provided on a lower wash arm, for a multiplicity of final-rinse nozzles 15a to be provided on at least one upper final-rinse arm, and for a multiplicity of final-rinse nozzles 15b to be provided on at least one lower final-rinse arm.

(11) Before final-rinse liquid is sprayed during the final-rinse phase, in each case a quantity of wash liquid which corresponds to the final-rinse liquid is pumped out of the wash tank 12 by means of a drainage pump 5, the suction side of which is connected, via a discharge line, to a sump of the wash tank. If the wash tank 12 is empty prior to initial starting of the dishwasher 1 in the form of a batch dishwasher, it must first be filled with fresh water via a fresh water line (not shown) or with fresh water or another final-rinse liquid or wash liquid by means of the final-rinse system and the final-rinse pump 14 thereof.

(12) The final-rinse liquid may be fresh water or fresh water mixed with rinse aid. By contrast, the wash liquid contains detergent, which is added, preferably automatically, to the liquid contained in the wash tank 12 by means of a detergent-metering device (not shown). The abovementioned program control device controls the wash pumps 13, the final-rinse pump 14, the drainage pump 5 and the detergent-solution pump (not shown) in dependence on the cleaning program selected by an operator in each case using the program control device. At least one cleaning program is provided, and preferably a plurality of optionally selectable cleaning programs are provided.

(13) From the embodiment, which is illustrated in FIG. 1, of the dishwasher 1 according to the invention, the intake side of a final-rinse pump 14 is furthermore connected to an outlet of a boiler 22. The boiler 22 furthermore has an inlet which is connected to a fresh-water supply line 30, via which inlet either fresh water or fresh water with added rinse aid is supplied to the boiler 22. In the boiler 22, the liquid (pure fresh water or fresh water with added rinse aid) supplied via the inlet is heated up in accordance with a specific process sequence. Via the final-rinse pump 14, the intake side of which is connected to the boiler exit, the final-rinse liquid heated up in the boiler 22 can be supplied to the final-rinse nozzles 15a and 15b, via the final-rinse line system 17, for example during a fresh-water final-rinse phase. The final-rinse nozzles 15a and 15b are arranged in the treatment chamber 2, in order for the final-rinse liquid heated up in the boiler 22 to be sprayed onto the washware in the treatment chamber 2. Of course, it is also conceivable for the boiler to be supplied, via the inlet into the fresh-water supply line 30, with pure fresh water which, following heating in the boiler, has a rinse aid added thereto.

(14) In the embodiment of the dishwasher 1 according to the invention that is illustrated in FIGS. 1 and 2, the final-rinse system has a preferably electrically operated steam generator 39 whichas illustrated in the figuresmay be integrated, for example, in the boiler 22. In this case, a corresponding steam outlet 46 of the steam generator 39 is formed on the upper region of the boiler 22. The steam outlet 46 of the steam generator 39 is connected to the treatment chamber 2, via a steam line 46a, at a location situated above the wash tank 12 in order for the steam generated in the steam generator 39 to be introduced into said treatment chamber where necessary. The outlet opening of the steam line 46a is preferably located between the upper nozzles 11a, 15a of the wash system and fresh-water final-rinse system, respectively, and the lower nozzles 11b, 15b. Of course, other positions are nevertheless also possible.

(15) The boiler 22, which, according to the embodiments illustrated in FIGS. 1 and 2, serves for generating steam, where necessary, in addition to heating the final-rinse liquid, contains a heater 47. It is also possible for a level sensor 48, which controls, for example, a valve 49 of the fresh-water line 30, to be arranged in or on the boiler 22.

(16) The dishwasher 1 according to the invention furthermore has a drying device 40 for extracting moisture from the drying air circulating in the treatment chamber 2 continuously or when required. The drying device 40 has at least one sorption unit containing a reversibly dehydratable dry material. Said sorption unit 41 is customarily a container in which a reversibly dehydratable dry material is placed. Said dry material is preferably a sorption agent which contains zeolite. A suitable dry material is, in particular, type Y zeolite, since this material is particularly stable even under extreme hydrothermal conditions. The drying device furthermore contains at least one fan 44 for, where necessary, forming an air circuit in such a way that at least some of the air from the treatment chamber 2 is conducted through the sorption unit 41 via an air inlet 40a and is subsequently returned to the treatment chamber 2 via an air outlet 40b.

(17) As can be gathered in particular in FIGS. 1 and 2, the drying device 40 is arranged above the treatment chamber 2. In other words, the drying device 40 with the fan 44 and the sorption unit 41 is preferably mounted on the machine roof of the dishwasher 1. This has the advantage that, for example, the wash liquid already mentioned above can only pass into the interior of the drying device 40 with difficulty and therefore flows back exclusively into the wash tank 12 under the influence of the force of gravity. The dry material located in the sorption unit 41 is therefore effectively protected from spray water and condensation water.

(18) The air inlet 40a of the drying device 40 is connected to the treatment chamber 2 preferably via an inlet line 42, wherein the inlet line 42 is connected laterally (FIG. 2) or at the top (FIG. 1) to the treatment chamber 2. In an equivalent manner thereto, the air outlet 40b of the drying device is connected to the treatment chamber 2 preferably via an outlet line 43, wherein the outlet line 43 is connected laterally (FIG. 2) or at the top (FIG. 1) to the treatment chamber 2. It should be mentioned at this juncture that the inlet and outlet lines 42, 43 can both have a valve for closing the connection between treatment chamber and drying device 40 when required. An air circuit can be formed via the inlet and outlet lines 42, 43, with the aid of the associated fan 44, where necessary, in such a way that at least some of the air is sucked up out of the treatment chamber 2 and supplied to the sorption unit 41 via the inlet line 42. Said air sucked up from the treatment chamber 2 is subsequently conducted through the sorption unit 41 and the dry material and then returned to the treatment chamber 2 via the outlet 40b of the drying unit 40 and the outlet line 43.

(19) In order for it to be possible to regenerate the dry material of the sorption unit 41 during the desorption phase, it is necessaryas already explainedto heat the dry material correspondingly. For this purpose, in the case of the embodiments of the dishwasher 1 according to the invention that is illustrated in drawings 1 and 2, the sorption unit 41 is assigned a, for example, electrically operated heating device 45 which is intended to heat, where necessary, the dry material of the sorption unit 41 during a desorption phase or directly before the desorption phase is initiated. The desorption sub-process is carried out following the adsorption phase, to be precise by the sorption unit 41 being supplied with heat, for example in the form of electrical energy, steam, gas or hot water. Simultaneously or with a time lag, through the sorption unit 41 located in the desorption phase, air is blown out of the treatment chamber 2 of the dishwasher 1 via the inlet line 43, with the aid of the fan 44, said air absorbing the water desorbed as steam from the dry material.

(20) The heating unit 45 (merely illustrated schematically) can have a large number of heating elements which are arranged at an identical distance within the reversibly dehydratable material. The heating elements here may be, for example, heating rods or heating plates which are distributed over the entire volume of the sorption unit 41. The powerful binding forces in relation to water mean that the dry material should preferably be heated to 150 C. to over 300 C. in order to obtain as little residual moisture content within the dry material as possible. The large number of heating elements (not illustrated) should therefore be spaced in particular sufficiently far from the housing walls of the drying device 40 that said housing walls are not damaged by the high temperatures of up to 400.

(21) FIGS. 3 and 4 illustrate schematic views of two different embodiments of the drying device 40. The drying devices here are connected to the treatment chamber 2 via an air inlet 40a and also via an air outlet 40b. In order effectively to protect the sorption unit 41 from splashed water from the treatment chamber 2, the drying device 40 of the dishwasher 1 has a first splashed water protection device 50a between the air inlet 40a and the treatment chamber 2. In addition or alternatively thereto, the dishwasher can have a second splashed water protection device 50b between the air outlet 40b and the treatment chamber 2. The splashed water protection devices illustrated schematically in FIGS. 3 and 4 are, for example, curved lines, protective covers or lines with an obstacle. Of course, the splashed water devices are not restricted to the exemplary embodiments illustrated.

(22) The interior of the drying unit 40 contains a sorption unit 41 which consists of a reversibly dehydratable dry material which is held by a housing structure (for example perforated plates) which is not illustrated. The sorption unit 41 here is designed in particular in such a way that said sorption unit has a thickness D of 2 to 100 mm, preferably 10 to 50 mm and particularly preferably 15 to 40 mm, along the direction of flow of the air stream conducted out of the treatment chamber 2. The thickness of 2 to 100 mm ensures that the moist machine air is sufficiently dried without having to accept too high a flow resistance.

(23) The drying device 40 advantageously has a first air distributor 51 which is arranged between the fan 44 and the sorption unit 41 and is intended to orient the air stream perpendicularly to an entry surface of the sorption unit 41. In the embodiment according to FIG. 3, the first air distributor 51 accordingly has a multiplicity of air lamellae which are curved in such a manner that the air flow conveyed by the fan 44 is deflected at an angle of approximately 90 to the sorption unit 41. The individual air lamellae here become larger in size at increasing distance from the fan 44, as a result of which a uniform distribution of the air stream over the entire length of the sorption unit 41 is ensured. The air distributor 51 which is illustrated in FIG. 4 and is designed as a lattice behaves in a similar manner. At increasing distance from the fan 44, the thickness of the lattice, through which the air stream has to penetrate in order to reach the sorption unit 41, is reduced. It is therefore ensured in turn that identical portions of air flow even through the rear regions (on the right in the illustration). In other words, the flow resistance of the first air distributor, which is illustrated in FIG. 4, decreases at increasing distance from the fan 44, as a result of which a uniform distribution of the air stream within the sorption unit 41 is ensured.

(24) The drying device 40 can furthermore have a second air distributor 52, as is illustrated, for example, in FIG. 3. The second air distributor 52 is preferably arranged between the sorption unit 41 and the treatment chamber 2. The second air distributor 52 here is arranged in relation to the first air distributed 51 in such a way that the air stream is uniformly distributor over all of the dry material of the sorption unit 41. Specifically, it is preferably possible to influence the air flow within the sorption material 41 by means of the second air distributor 52. For this purpose, the second air distributor is preferably designed as a perforated plate or slotted plate, wherein the latter has an inhomogeneous distribution of openings. Accordingly, an increased air stream can be forced through the sorption unit 41 at locations having a plurality of openings or larger openings, whereas a reduced flow takes place in the sorption unit 41 because of the increased flow resistance at locations having fewer or smaller openings or slots. A particularly homogeneous distribution of the air stream over all of the dry material of the sorption unit 41 can be achieved by a skilled combination of the first and second air distributors 51, 52.

(25) The method according to the invention for operating a dishwasher 1 in the form of a batch dishwasher will be explained in more detail below with reference to the embodiments illustrated in FIGS. 1 to 4:

(26) In a first method step, during an adsorption phase, air is conducted out of the treatment chamber 2 through a sorption unit 41, which contains a reversibly dehydratable dry material, in such a way that the dry material absorbs moisture from the air stream, wherein the air is then returned to the treatment chamber 2. During this adsorption phase, in which moisture from air extracted from the treatment chamber 2 is adsorbed by the dry material of the sorption unit 41, adsorption heat is also released, as a consequence of which the air which has been conducted through the sorption unit 41 is correspondingly heated. The hot air which is dried following passage through the sorption unit 41 is returned to the treatment chamber 2 of the dishwasher 1 and can be used for drying the washware accommodated in the treatment chamber 2. In this respect, it is preferred if the adsorption phase of the sorption unit 41 takes place simultaneously or in a chronologically overlapping manner with the drying phase of the dishwasher 1 in order to be able to use the heat released during the adsorption of moisture from the dry material of the sorption unit 41 in order to dry the washware. The higher air temperature here permits a significant improvement in the drying quality especially for washware made from plastics material. In particular, the drying time can therefore also be considerably reduced under some circumstances. This is an important factor in particular for commercial dishwashing.

(27) The desorption phase, during which the dry material of the sorption unit 41 is heated and air is conducted out of the treatment chamber 2 through the sorption unit 41, which contains the heated dry material, constitutes a second method step of the method according to the invention. Moisture here is desorbed from the dry material and at least some of the thermal energy which has previously been introduced into the dry material and at least some of the moisture desorbed from the dry material are discharged out of the sorption unit 41 as steam with the aid of the air stream conducted through the sorption unit 41. The steam arising in the process can be used, for example, for steam cleaning the washware during the final-rinse phase. In this respect, it is preferred if the second method step, i.e. the desorption phase, at least partly takes place during the wash phase and/or at least partly takes place during the final-rinse phase, in order to be able to use the steam arising during the desorption operation for further cleaning of the washware. The use of the steam makes it conceivable in particular to be able partially or entirely to dispense with environmentally harmful chemicals which are used, for example, during the final-rinse process.

(28) It should be noted at this juncture that the amount of moisture in the dry material of the sorption unit 41 can be determined continuously or at predefinable times or in the case of predefinable events during the adsorption phase and/or the desorption phase. This takes place in particular by means of a sensor unit which, for example, measures the weight of the dry material, the duration of the desorption phase, the moisture content or the temperature of the air at the air outlet of the drying device. The sensor unit (not illustrated) can therefore be used together with the program control unit in order to initiate the different program sequences on the basis of the moisture content of the dry material.

(29) Furthermore, it is preferred if the adsorption phase takes up 30 sec to 5 min, preferably 1 min to 3 min. In contrast, the desorption phase can take place within 5 sec to 5 min, preferably 20 sec to 3 min and particularly preferably 1 min to 2 min.

(30) In the case of commercial dishwashers, it is important in particular for the desorption phase to operate as sufficiently as possible and to be short. For this purpose, as great a quantity of heat as possible has to be introduced into the sorption material within as short a time as possible, wherein care has to be taken at the same time to ensure that the sorption material does not overheat. For this purpose, it is provided in the solution according to the invention that electrical heating coils are arranged in the sorption unit in order, in the desorption phase, to introduce the thermal energy, which is necessary for regenerating the dry material, into the sorption material directly. In addition thereto, care should be taken to ensure that, during each desorption phase, the sorption unit 41 is at least subjected to forced ventilation in such a way that recondensation of desorbed steam in the sorption unit 41 is effectively prevented. In particular, care should be taken to ensure that condensate which could lead to damage, for example, of the heating unit 45 integrated in the sorption unit, cannot form in the interior of the sorption unit.

(31) It has been shown in this connection that even 10 liters of air are sufficient in order effectively to expel the desorbed steam from the sorption unit during a desorption phase. Of course, however, greater quantities of air which are blown through the sorption unit 41, for example by means of the fan 44, during the desorption phase are also possible.

(32) The air is preferably blown continuously or intermittently through the sorption unit 41 during each desorption phase.

(33) According to one aspect of the invention, it is provided that the temperature of the heated dry material is measured continuously or at predefined or predefinable times or in the case of predefined or predefinable events in the sorption unit 41 during each desorption phase, and wherein the output capacity of the fan 44 is controlled as a function of the measured temperature of the heated dry material in such a way that the dry material assumes a temperature of 150 C. to 300 C., and preferably always less than 500 C.

(34) According to a further aspect of the invention, it is provided that the temperature of the air which is forced through the heated dry material is measured continuously or at predefined or predefinable times or in the case of predefined or predefinable events during each desorption phase, and wherein the output capacity of the fan 44 is controlled as a function of the measured temperature of the air which is forced through the heated dry material in such a way that the air which is forced through the dry material assumes a temperature of less than 200 C., and preferably of less than 150 C.

(35) According to one aspect of the invention, it is provided that each desorption phase takes place within a time period of from 20 to 150 seconds, and preferably in a time period of from 40 to 90 seconds.

(36) According to one aspect of the invention, it is provided that a total of 60 to 1000 kJ, and preferably a total of 150 to 500 kJ, of thermal energy is supplied to the dry material during each desorption phase.

(37) According to one aspect of the invention, it is provided that the fan 44 is actuated in such a way that the volumetric flow rate of air which is forced through the dry material during each desorption phase is in a range of between 0.5 to 200 m.sup.3/h, and preferably in a range of between 0.10 to 40 m.sup.3/h.

(38) According to one aspect of the invention, it is provided that each desorption phase is subdivided with respect to time into an initial first time period and a subsequent second time period, and wherein the fan 44 is actuated in such a way that a quantity of air which is forced through the dry material during the first time period per unit time is lower than a quantity of air which is forced through the dry material during the subsequent second time period per unit time. The dry material can thereby be heated even more rapidly.

(39) According to one aspect of the invention, it is provided that each desorption phase is subdivided with respect to time into an initial heating phase, during which thermal energy is supplied to the dry material with the aid of a heating device at the same time as forced ventilation, and into a subsequent follow-up phase, during which only forced ventilation takes place and no thermal energy is supplied to the dry material by means of the heating device.

(40) The invention is not restricted to the embodiments of a dishwasher according to the invention that are illustrated in the figures, but rather is revealed with reference to an overview of all of the features disclosed therein. In particular, the invention can also be used equivalently in the technical field of washer dryers. Furthermore, it should be mentioned that the drying device 40 is not restricted to having an individual fan 44 and an individual sorption unit 41, but rather it is entirely possible for the drying device to include two or more of these components. As has already been mentioned above, the drying device 40 can also have, for example, a heat exchanger (not illustrated) which serves for further reducing the energy consumption.

(41) TABLE-US-00001 List of Reference Numbers 1 Dishwasher 2 Treatment chamber 3 Washwater 4 Discharge line 5 Drainage pump 11a, 11b Wash nozzles 12 Wash tank 13 Wash pump 14 Final-rinse pump 15a, 15b Final-rinse nozzles 16 Wash liquid line system 17 Final-rinse liquid line system 22 Boiler 30 Fresh-water supply line 39 Steam generator 40 Drying unit 40a Air inlet 40b Air outlet 41 Sorption unit 42 Inlet line 43 Outlet line 44 Fan 45 Heating unit 46 Steam outlet 46a Steam line 47 Heater 48 Level sensor 49 Valve 50a First splashed water protection device 50b Second splashed water protection device 51 First air distributor 52 Second air distributor