NOZZLE ARRANGEMENTS, AND DISHWASHER COMPRISING

A SYSTEM OF THIS KIND

Description

[0001] The present invention relates, in particular, to dishwashers, and primarily to commercial dishwashers or utensil washers, which are in the form of box-type dishwasher or conveyor dishwashers. In particular, the invention relates to dishwashers in which automatic cleaning assistance is implemented in order to be able to automatically clean the dishwashers as required.

[0002] Furthermore, the present invention relates to a cleaning system for automatically cleaning the interior of dishwashers, in particular commercial dishwashers.

[0003] Box-type dishwashers are dishwashers which can be manually loaded and unloaded. The box-type dishwashers may be hood-type dishwashers or front-loader dishwashers. Front-loader dishwashers may be under-counter machines, top-counter machines or free-standing front-loader dishwashers.

[0004] A dishwasher which is in the form of a box-type dishwasher usually has a treatment chamber for cleaning washware. The treatment chamber generally has arranged beneath it a wash tank in which liquid from the treatment chamber can flow back due to the force of gravity. The wash tank contains wash liquid which is usually water to which detergent may be added if required.

[0005] A dishwasher which is in the form of a box-type dishwasher also generally has a wash system with a wash pump, a line system which is connected to the wash pump, and a large number of spray nozzles which are formed in at least one wash arm. The wash liquid contained in the wash tank can be conveyed from the wash pump to the spray nozzles by means of the line system and can be sprayed onto the washware to be cleaned through the spray nozzles in the treatment chamber. The sprayed wash liquid then flows back into the wash tank.

[0006] Conveyor dishwashers are, in particular, flight-type dishwashers or rack-conveyor dishwashers. Conveyor dishwashers are usually used in the commercial sector. In contrast to box-type dishwashers, in which the washware to be cleaned remains stationary in the machine during the cleaning process, the washware is transported through various treatment zones of the conveyor dishwasher in the case of conveyor dishwashers.

[0007] A conveyor dishwasher usually has at least one prewash zone and at least one main wash zone which is arranged downstream of the prewash zone or zones as seen in the transportation direction of the washware. As seen in the transportation direction, at least one postwash zone and at least one final rinse zone, which is downstream of the postwash zone, are generally arranged downstream of the main wash zone or zones. As seen in the transportation direction, the washware, which is either held directly on a conveyor belt or retained by racks, runs, in the transportation direction, through an inlet tunnel, the following prewash zone or zones, main wash zone or zones, postwash zone or zones, final rinse zone or zones and a drying zone, into an outlet section.

[0008] The abovementioned wash zones of the conveyor dishwasher each have an associated wash system which has a wash pump and a line system which is connected to the wash pump and by means of which liquid is supplied to the spray nozzles of the wash zone. The wash liquid which is supplied to the spray nozzles is sprayed onto the washware, which is transported through the respective wash zones by a transportation apparatus of the conveyor dishwasher, in the respective wash zones. Each wash zone usually has an associated tank in which sprayed liquid is accommodated and/or in which liquid for the spray nozzles of the relevant zones is provided.

[0009] In the case of the conveyor dishwashers which are usually known from the prior art, final rinse liquid in the form of fresh water, which may be pure or mixed with further additives, for example rinse aid, is sprayed onto the washware by means of the spray nozzles of the final rinse zone. Usually at least some of the final rinse liquid sprayed is transported from zone to zone, counter to the transportation direction of the washware, by means of a cascade system.

[0010] The sprayed final rinse liquid is generally collected in a tank (postwash tank) of the postwash zone, from which it is conveyed to the spray nozzles (postwash nozzles) of the postwash zone by means of the wash pump of the wash system which is part of the postwash zone. In the postwash zone, wash liquid is rinsed off from the washware. The liquid which accumulates in the process generally flows into the wash tank of the at least one main wash zone which is arranged upstream of the postwash zone as seen in the transportation direction of the washware. Here, the liquid is usually provided with a detergent and is sprayed onto the washware by a pump system (wash pump), which is part of the wash system of the main wash zone, by means of the nozzles (wash nozzles) of the main wash zone. If no further main wash zone is provided - the liquid then usually flows from the wash tank of the main wash zone into the prewash tank of the prewash zone. The liquid in the prewash tank is sprayed onto the washware by means of a pump system, which is part of the wash system of the prewash zone, by means of the prewash nozzle of the prewash zone in order to remove coarse dirt from the washware.

[0011] Irrespective of whether the dishwasher is in the form of a box -type dishwasher or a conveyor dishwasher, the dishwashers under consideration here and, in particular, commercial dishwashers therefore usually comprise at least one wash system which has a wash pump which ensures a virtually constant water circulation rate for the duration of a wash process in the treatment chamber (in the case of box-type dishwashers) or in the respective treatment zone (in the case of conveyor dishwashers). The respective wash pumps of the wash systems are switched on and switched off by a control device (machine controller) which is part of the dishwasher.

[0012] Furthermore, the dishwashers under consideration here and, in particular, commercial dishwashers usually comprise at least one final rinse system in order to spray final rinse liquid, in particular fresh water, onto the washware for the purpose of final rinsing.

[0013] The dishwasher is and has to be cleaned at the end of each working day. This involves a large number of working steps which have to be performed manually.

[0014] In order to clean, for example, a conveyor dishwasher, the wash arms and the screen systems of the individual wash systems first have to be removed. Since a conveyor dishwasher generally has a plurality of wash zones which are arranged one behind the other, and therefore a corresponding large number of wash systems, these working steps have to be carried out several times. [0015] The uninstalled screen systems are then manually hosed down with hot water and additionally manually scrubbed - depending on the degree of soiling. In the case of the uninstalled wash arms, the cleaning end caps which are usually arranged at the end of the wash arms are first removed, so that each individual wash tube of a wash arm can then be flushed with water. Finally, the wash arm is completely cleaned, that is to say hosed down and manually scrubbed. The final rinse arms are likewise hosed down with water and possibly manually scrubbed. Final rinse arms are generally not provided with cleaning end caps since no dirt is expected to be found inside the final rinse tubes.

[0016] The loading zone of a conveyor dishwasher, which is the treatment zone which is soiled to the greatest extent, is hosed down with hot water and sometimes (if necessary) manually cleaned with a cleaning cloth and possibly with the aid of a detergent solution during the cleaning process.

[0017] Once the individual treatment zones of the conveyor dishwasher have been completely emptied, each zone is purged with fresh water and sometimes even (if necessary) manually cleaned with a cleaning cloth and/or with the aid of a detergent solution. The inspection doors, which can be designed as sliding doors or swing doors, also form part of the interior cleaning system. The unloading zone of the conveyor dishwasher should likewise be hosed down with fresh water even though it is generally least soiled.

[0018] The entire cleaning operation for a conveyor dishwasher takes between 30 and 40 minutes depending on the size of the machine, with the quantity of fresh water used for cleaning the machine being between 400 and 600 liters.

[0019] After the interior of the conveyor dishwasher has been cleaned and after the previously uninstalled wash system components have been cleaned, the individual parts of the wash systems have to be re-installed into the conveyor dishwasher.

[0020] The invention is based on the object of specifying automatic cleaning assistance for dishwashers, in particular conveyor dishwashers, such as flight-type or rack-conveyor dishwashers for example, with which automatic cleaning assistance the cleaning of the interior of the dishwasher which has to be carried out at the end of a working day can be made more efficient. [0021] A particular objective is to specify a solution with which at least some of the working steps which are required for cleaning the interior of dishwashers can be carried out automatically in order to thus save on personnel and at the same time to be able to reduce the resources (water, energy, chemicals) used for cleaning purposes.

[0022] The invention is further based on the object of specifying an automatic cleaning assistance arrangement for cleaning the interior of dishwashers, in particular conveyor dishwashers, wherein the automatic cleaning assistance arrangement can be implemented with as low an installation space requirement as possible and likewise with as low a level of expenditure on assembly as possible in as cost-effective a manner as possible.

[0023] The object on which the invention is based is achieved, in particular, by a cleaning system for automatically cleaning the interior of dishwashers, in particular conveyor dishwashers, wherein this cleaning system has a system for selectively feeding liquid, in particular fresh water, to various nozzle arrangements which are designed separately from one another. The system for selective liquid supply which is used in the cleaning system according to the invention is mentioned in independent patent claim 1, wherein

advantageous developments thereof are indicated in the dependent claims.

[0024] The object on which the present invention is based is also achieved by the subject matter of coordinate patent claim 21 which is directed to a system for automatically cleaning the interior of dishwashers.

[0025] In respect of the dishwasher, the object on which the invention is based is further achieved by the subject matter of coordinate patent claim 22.

[0026] The proposed automatic cleaning system is accordingly distinguished in that a system for selectively feeding liquid, in particular fresh water, to various nozzle

arrangements which are designed separately from one another is used in the case of said cleaning system. The various nozzle arrangements may, for example, be located in different zones of the machine and/or in different spray arms of the machine. This system for selectively supplying liquid allows the automatic cleaning assistance to be implemented in as compact and cost-effective, but nevertheless effective, a manner as possible. [0027] The invention equally relates to a cleaning system for automatically cleaning the interior of dishwashers, in particular commercial dishwashers, which are designed as box- type dishwashers or conveyor dishwashers, wherein the cleaning system has a first cleaning nozzle arrangement and also at least one further, second cleaning nozzle arrangement. The first cleaning nozzle arrangement and the at least one further, second cleaning nozzle arrangement each has at least one spray nozzle which is arranged or is to be accommodated in the interior of the dishwasher in order to spray cleaning liquid, in particular fresh water, in particular onto the inner walls of the dishwasher in order to clean the interior in the cleaning mode of the dishwasher. To this end, the spray nozzles of the cleaning nozzle arrangements are preferably designed in the form of rotary nozzles in order to enable each spray nozzle to cover as large a region as possible.

[0028] The corresponding spray nozzles of the first cleaning nozzle arrangement and of the at least one further, second cleaning nozzle arrangement are positioned at suitable points within the dishwasher to be cleaned, wherein a greater number of spray nozzles is provided in regions with a relatively high degree of soiling, in particular therefore in the region of the loading zone in the case of a conveyor dishwasher for example, in comparison to regions of the dishwasher which are least soiled, such as in the region of the final rinse zone in the case of a conveyor dishwasher for example.

[0029] The first cleaning nozzle arrangement has an associated first line system by means of which cleaning liquid, in particular fresh water, is fed to the spray nozzles of the first cleaning nozzle arrangement as required and, in particular, in the cleaning mode of the dishwasher. In the same way, the at least one further, second cleaning nozzle arrangement has a corresponding associated second line system by means of which cleaning liquid, in particular fresh water, can be fed to the spray nozzles, which form part of the second cleaning nozzle arrangement, as required in the cleaning mode of the dishwasher. In contrast to the conventional practice in commercial dishwashing operations in particular, the line systems of the cleaning nozzle arrangement in the case of the solution according to the invention are, however, not directly flow-connected to the delivery end of a

corresponding feed pump for supplying cleaning liquid, in particular fresh water, since a configuration of this kind would lead to a high installation space requirement and also a relatively high level of expenditure on assembly and to high costs for realizing the cleaning system. Specifically, a configuration in which the individual line systems of the cleaning nozzle arrangements are directly flow-connected to the delivery end of corresponding feed pumps would lead to a plurality of valve arrangements which are separated from one another having to be provided. Furthermore, the achievable conveying capacity of the feed pump would have to be designed to be correspondingly high.

[0030] In order to bypass these disadvantages, it is provided, according to the invention, that the cleaning system is provided with a system for selectively feeding liquid, in particular fresh water, to the various cleaning nozzle arrangements.

[0031] The system for selectively supplying liquid has a liquid distributor comprising a liquid inlet, a first liquid outlet and at least one further, second liquid outlet. The liquid inlet of the liquid distributor can be flow-connected to a liquid source, in particular a fresh water source, while the first liquid outlet of the liquid distributor is flow-connected or can be flow-connected to the first line system which is associated with the first nozzle arrangement, and while the at least one further, second liquid outlet of the liquid distributor is flow-connected or can be flow-connected to the second line system which is associated with the at least one further, second cleaning nozzle arrangement. According to the invention, it is in particular provided here that the liquid distributor is designed to sequentially establish a fluid connection between the liquid inlet and the individual liquid outlets of the fluid distributor in accordance with a predefined sequence of events.

[0032] The solution according to the invention, and in particular the provision of a liquid distributor for selectively feeding liquid to the various cleaning nozzle arrangements, which are arranged separately from one another, of the cleaning system, allow automatic cleaning assistance to be implemented in a dishwasher, in particular in a conveyor dishwasher, in a manner which is particularly easy to realize, but is nevertheless effective.

[0033] In particular, the solution according to the invention means a large number of lined-up, electrically operable solenoid valves (series valves) are no longer required in order to correspondingly drive the individual spray nozzles of the cleaning nozzle arrangements in pairs.

[0034] Since it is possible to dispense with lining up individual valves, only a relatively small amount of installation space is required in order to implement the automatic cleaning assistance. Furthermore, the automatic cleaning assistance can be implemented with a considerably lower level of expenditure on assembly since it is no longer required to provide electrical actuation of the solenoid valves which has to be performed separately. Since it is furthermore possible to (at least partially) dispense with the usually required electrically operable solenoid valves, the costs for implementing the automatic cleaning assistance are minimized.

[0035] As discussed in more detail below, the liquid distributor according to the invention which serves to selectively feed liquid, in particular fresh water, to the various nozzle arrangements which are designed separately from one another, is a compact valve which can be operated in a cost-effective and, in particular, hydraulic manner and which can cyclically open and close a plurality of liquid outlets which are separated from one another, in particular without separate electrical actuation.

[0036] Specifically, it is provided according to a preferred realization of the liquid distributor according to the invention that said liquid distributor has a distributor housing and a switching cylinder which is accommodated in the distributor housing, wherein the liquid inlet and the liquid outlets of the liquid distributor issue into the distributor housing. In this case, the switching cylinder is preferably mounted in the distributor housing such that it can move, and in particular can rotate, relative to the liquid inlet and the liquid outlets in such a way that, depending on the relative position of the switching cylinder in relation to the liquid inlet and the liquid outlets, a fluid connection can be selectively established between the liquid inlet and the individual liquid outlets by means of the switching cylinder.

[0037] In this connection, it is feasible, in particular, for the distributor housing to have a first housing region, into which the liquid inlet issues, and an opposite second housing region, into which the individual liquid outlets issue, wherein the switching cylinder can be rotated not only relative to the distributor housing about its longitudinal axis but also can be moved relative to the distributor housing in the axial direction of the distributor housing.

[0038] In particular, this refinement allows the switching cylinder to be mounted in the distributor housing in such a way that said switching cylinder can be moved from a home position to a switching position in the direction of the second housing region owing to the pressure of a liquid which is fed into the first housing region of the distributor housing by means of the liquid inlet. It should be taken into account here that the terms "home position" and "switching position" used in this document each relate to the position of the switching cylinder in the axial direction of the distributor housing but do not take into account the rotation position, that is to say the rotation of the switching cylinder about its longitudinal axis which points in the axial direction of the distributor housing.

[0039] In the last-mentioned embodiment, it is advantageous when a return mechanism, for example in the form of a return spring, is further provided in the distributor housing in order to reset the switching cylinder to its home position again when the pressure of the liquid which is fed into the first housing region falls below a predefined or predefinable value. In other words, the switching cylinder is preferably mounted in the distributor housing in such a way that said switching cylinder is in the switching position on the second housing region when the liquid inlet of the distributor housing is flow-connected to the liquid source, in particular fresh water source, while the switching cylinder returns to its home position in the first housing region of the distributor housing again on account of the return mechanism when the flow connection between the liquid inlet of the distributor housing and the fluid source has been interrupted or sufficiently restricted.

[0040] According to one aspect of the present invention, the liquid distributor is provided with a kind of "revolver" mechanism, that is to say a mechanism in which the switching cylinder is always rotated about its longitudinal axis by a predefined or predefinable angular value when the switching cylinder has moved from its home position on the first housing region to the switching position on the second housing region and back again. In this way, a fluid connection can be established between the liquid inlet and a first of the at least two liquid outlets of the liquid distributor - depending on the rotation position of the switching cylinder relative to the distributor housing and in particular relative to the second housing region of the distributor housing. Since the switching cylinder is then moved from the home position to the switching position and back, as a result of which the switching cylinder is once again rotated about its longitudinal axis by a predefined or predefinable angular value, a fluid connection can be established between the liquid inlet and a second of the at least two liquid outlets of the liquid distributor.

[0041] In order to achieve this functionality, it is feasible according to one aspect of the invention for the switching cylinder to have a first region, which faces the first housing region, and an opposite second region, which faces the second housing region, wherein a first tooth mechanism, which interacts with the first housing region, is associated with the first region of the switching cylinder, and a second tooth mechanism, which interacts with the second housing region, is associated with the second region of the switching cylinder.

[0042] In this connection, it is feasible, in particular, for the switching cylinder to be of sleeve-like design at least in regions of its first and/or second region, wherein a toothed ring can be at least partially formed in this sleeve-like region. In this connection, it is further advantageous when serrations which complement the toothed ring are provided in the first and/or second housing region. In this way, the switching cylinder can be rotated about its longitudinal axis by a predefined or predefinable angular value when it is moved from the home position to the switching position and back.

[0043] However, it goes without saying that other mechanisms can also be used for thie purpose, such as, for example, a mechanism which is based on the latching-in mechanism which is used in retractable ballpoint pens. Since this latching-in mechanism should have long been known for decades, the design and manner of operation of the latching-in mechanism of retractable ballpoint pens will not be described in any detail at this point.

[0044] In a preferred development of the system according to the invention for selectively feeding liquids to different nozzle arrangements, in particular cleaning nozzle arrangements, a sensor device is provided, which is designed for detecting that liquid outlet which forms a fluid connection with the liquid inlet of the liquid distributor. In this connection, it is feasible, for example, for the sensor device to be designed to detect the rotation position of the switching cylinder relative to the distributor housing and, in particular, relative to the second housing region of the distributor housing. Since the switching cylinder is secondly designed to establish a fluid connection between the liquid inlet and one (an individual one) of the liquid outlets in its switching position, an at least indirect conclusion about that liquid outlet which forms a fluid connection with the liquid inlet of the liquid distributor can be drawn on the basis of the rotation position of the switching cylinder relative to the second housing region of the distributor housing. [0045] In a manner which can be realized particularly easily, but nevertheless effectively, the sensor device has, for this purpose, at least one reed sensor which is associated with the liquid distributor.

[0046] In respect of the liquid source to which the liquid inlet of the liquid distributor can be flow-connected, it should be noted that the liquid source preferably has a fresh water supply system connection and is formed, in particular, by a fresh water supply system connection.

[0047] As an alternative or in addition, it is, however, also feasible in this connection for the liquid source to have a tank, in particular a fresh water tank, which has an outlet which is flow-connected or can be flow-connected to the intake end of a feed pump, in particular a fresh water pump. This tank can be filled with fresh water by means of the fresh water supply system connection as required.

[0048] In this embodiment, it is advantageous when the liquid inlet of the liquid distributor is flow-connected or can be flow-connected to the delivery end of the feed pump. In a particularly preferred realization of the solution according to the invention in the case of which the automatic cleaning system or the liquid distributor is used in a dishwasher, in particular a conveyor dishwasher, a valve arrangement is additionally provided in order to, as required, establish a flow connection between the liquid inlet of the liquid distributor and the liquid source or the delivery end of the feed pump which is associated with the liquid source. The valve arrangement is preferably designed in such a way that the liquid inlet of the liquid distributor is flow-connected, as required, to the liquid source or to the delivery end of the feed pump which is associated with the liquid source, or the liquid source or the delivery end of the feed pump which is associated with the liquid source is directly, that is to say without the interposition of the liquid distributor, flow- connected to a line system which cannot be supplied with liquid by means of the liquid distributor.

[0049] This line system which cannot be supplied with liquid by means of the liquid distributor is, in particular, the line system of a final rinse system of a dishwasher, in particular conveyor dishwasher. This line system has an associated nozzle arrangement comprising spray nozzles (final rinse nozzles) in order to spray the liquid (final rinse liquid), which is supplied directly to the line system of the final rinse system by means of the valve arrangement, in the fresh water final rinse zone as required, that is to say in particular when the dishwasher is not in the cleaning mode.

[0050] The invention relates not only to a system for automatically cleaning the interior of a dishwasher or a system for selectively feeding liquid, in particular fresh water, to various nozzle arrangements, in particular cleaning nozzle arrangements, which are designed separately from one another, but also to a dishwasher, in particular a commercial conveyor dishwasher, in which the cleaning system according to the invention is implemented.

[0051] Therefore, the invention also relates, in particular, to a dishwasher comprising a fresh water final rinse system for fresh water final rinsing of washware and comprising a cleaning system for cleaning the interior of the dishwasher as required. The fresh water final rinse system has a final rinse nozzle arrangement comprising at least one final rinse nozzle and has a final rinse line system which is associated with the final rinse nozzle arrangement. The said final rinse line system is directly flow-connected, as required, that is to say in particular when the dishwasher is not in the cleaning mode and fresh water final rinsing is to be carried out, to the fresh water source or the delivery end of a feed pump which is associated with the fresh water source, and in particular without the interposition of the liquid distributor.

[0052] The cleaning system of the dishwasher according to the invention has a first cleaning nozzle arrangement comprising a first line system, which is associated with the first cleaning nozzle arrangement, and at least one further, second cleaning nozzle arrangement comprising at least one second line system, which is associated with the at least one further, second cleaning nozzle arrangement. Said at least two line systems are flow-connected selectively and as required to the liquid source (in particular fresh water source) or to the delivery end of the feed pump which is associated with the liquid source in order to supply liquid, in particular fresh water, to the corresponding cleaning nozzle arrangements by means of the liquid distributor.

[0053] Exemplary embodiments of the solution according to the invention will be described in more detail below with reference to the appended drawings. [0054] In the drawings:

[0055] FIG. 1 schematically shows a dishwasher in the form of a conveyor dishwasher for explaining the general design and manner of operation of a dishwasher of this kind;

[0056] FIG. 2 shows a hydraulic diagram of an exemplary embodiment of the cleaning system according to the invention for automatically cleaning the interior of a dishwasher, in particular a conveyor dishwasher; and

[0057] FIGS. 3A-3D show isometric exploded illustrations of an exemplary embodiment of a liquid distributor which can be used, for example, in the cleaning system according to FIG. 2.

[0058] FIG. 1 shows a conveyor dishwasher 2 as an example of a dishwasher in which the cleaning system according to the invention for automatically cleaning the interior can be implemented. Even if the following description of figures primarily makes reference to dishwashers which are designed as conveyor dishwashers, it should be noted that the cleaning system according to the invention is suitable in the same way for automatically cleaning the interior of dishwashers which are designed as box— type dishwashers.

Accordingly, the liquid distributor according to the invention of said cleaning system is also suitable for use in dishwashers which are in the form of box-type dishwashers.

[0059] The dishwasher 2 schematically illustrated in FIG. 1 for explaining the general design and the manner of operation of a conveyor dishwasher has a transportation apparatus 4 for transporting washware, not illustrated in FIG. 1, through the conveyor dishwasher 2 in a transportation direction 8. The conveyor dishwasher 2 further has at least one wash zone, for example as illustrated in FIG. 1, a prewash zone 12 and a main wash zone 14 which is arranged downstream of the prewash zone 12 as seen in the transportation direction 8.

[0060] As seen in the transportation direction 8, a postwash zone 16 is arranged downstream of the at least one wash zone 12, 14, and at least one final rinse zone, for example only a single fresh water final rinse zone 18 as illustrated, is arranged downstream of the postwash zone 16. In the conveyor dishwasher 2 schematically illustrated in FIG. 1, the fresh water final rinse zone 18 is followed as seen in the transportation direction 8 of the washware by a drying zone 40. The respective zones 12, 14, 16, 18, 40 of the conveyor dishwasher 2 can be separated from one another by means of separating curtains 47.

[0061] In the embodiment schematically illustrated in FIG. 1, the inlet tunnel 10 itself is also separated from the inlet 11 by a separating curtain 47. The provision of the separating curtains 47 prevents wash liquid and final rinse liquid spraying between zones and prevents vapors escaping from the conveyor dishwasher 2.

[0062] Said treatment zones 12, 14, 16, 18 of the conveyor dishwasher 2 have associated spray nozzles 20, 22, 24, 26, 28, 30. These spray nozzles 20, 22, 24, 26, 28, 30 serve to spray liquid onto the washware as said washware is transported through the respective treatment zones 12, 14, 16, 18 by the transportation apparatus 4. The individual spray systems of the treatment zones 12, 14, 16, 18 ensure that the washware to be treated is hosed down both from the top and from the bottom.

[0063] However, in the conveyor dishwasher 2 schematically illustrated in FIG. 1, the fresh water final rinse zone 18 not only has downwardly directed upper spray nozzles 20 and upwardly directed lower spray nozzles 22, but also transversely directed lateral spray nozzles 24 on either side of the transportation apparatus 4. The use of lateral spray nozzles 24 permits areas of the washware (areas of the dishes) to be sprayed with final rinse liquid in a targeted manner in shadow zones too. The use of lateral spray nozzles 24 in the fresh water final rinse zone 18 has a significant advantage in terms of the final rinse result (effective rinsing-off of detergent residues from dish surfaces in shadow zones too) over systems in which only upper and lower spray nozzles 20, 22 and no transversely directed lateral spray nozzles 24 are provided in the fresh water final rinse zone 18, specifically when the transportation system is fully loaded, that is to say with plate-to-plate loading of the dish rack.

[0064] The postwash zone 16, main wash zone 14 and prewash zone 12 also have associated tanks (postwash tank 32, main wash tank 34, prewash tank 36) for

accommodating sprayed liquid and/or for providing liquid for the spray nozzles 26, 28, 30 of the relevant treatment zones 14, 16, 18. [0065] Final rinse liquid, which comprises fresh water with rinse aid which is added in a metered fashion, is sprayed onto the washware, not illustrated, by means of the spray nozzles 20, 22, 24 of the fresh water final rinse zone 18 which are arranged above and below the conveyor apparatus 4 and on the side in the conveyor dishwasher 2 schematically illustrated in FIG. 1. A portion of the sprayed final rinse liquid is conveyed from treatment zone to treatment zone via a cascade system in the opposite direction to the transportation direction 8 of the washware. The remaining portion of the final rinse liquid which is sprayed in the fresh water final rinse zone 18 is conducted directly into the prewash tank 36, which is associated with the prewash zone 12, by means of a valve VI and a bypass line 38.

[0066] In the cascade system, the final rinse liquid which is sprayed by the final rinse nozzles 20, 22, 24 flows from the fresh water final rinse zone 18 into the postwash tank 32, which is associated with the postwash zone 16, due to the force of gravity. The final rinse liquid which is sprayed in the fresh water final rinse zone 18 and collected by the postwash tank 32 is then delivered to the spray nozzles (postwash nozzles 25) of the postwash zone 16 with the aid of a postwash pump 45. Wash liquid is rinsed off from the washware in the postwash zone 16. The liquid (postwash liquid) produced in the process flows into the main wash tank 34, which is associated with the main wash zone 14, due to the force of gravity. A discharge element 39, for example a discharge base or a baffle plate, which conducts the postwash liquid which is sprayed by the postwash nozzles 26 into the main wash tank 34, is preferably provided for this purpose.

[0067] According to another embodiment, not shown in the drawings, the outlet element 39 can be dispensed with if the main wash tank 34 extends as far as beneath the postwash nozzles 26 of the postwash zone 16.

[0068] The liquid accommodated by the main wash tank 34 of the main wash zone 14 is usually provided with a detergent and sprayed onto the washware by means of the spray nozzles (main wash nozzles 28) of the main wash zone 14 with the aid of a main wash pump 35. The wash liquid sprayed by the main wash nozzles 28 flows back into the main wash tank 34 due to the force of gravity. [0069] The main wash tank 34 is fluidically connected to the prewash tank 36, which is associated with the prewash zone 12, via an overflow line 37. The wash liquid which is sprayed in the main wash zone 14 enters the prewash tank 36 via this overflow line 37 when there is a sufficient quantity of wash liquid accommodated in the main wash tank 34.

[0070] The liquid accommodated in the prewash tank 36 of the prewash zone 12 is then sprayed onto the washware by means of the spray nozzles (prewash nozzles 30) of the prewash zone 12 with the aid of a prewash pump 33 in order to remove coarse particles of dirt from the washware. The wash liquid sprayed by the prewash nozzles 30 flows back into the prewash tank 36 due to the force of gravity.

[0071] The prewash tank 36 is provided with an overflow line 31 which is used to feed the excess quantity of liquid to a heat treatment device as waste water if a liquid level in the prewash tank 36 is exceeded.

[0072] As already indicated, the liquid sprayed in the main-wash zone 14 and in the prewash zone 12 preferably contains detergent which is added in a metered fashion with the aid of a detergent metering apparatus (not shown in the drawings), for example, to the liquid accommodated in the main wash tank 34 of the main wash zone 14.

[0073] As already mentioned, the fresh water final rinse zone 18 is followed by the drying zone 40 as seen in the transportation direction 8 of the washware. In the drying zone 40, the washware is dried using dry and heated air in order to blow off and/or dry up the moisture on the washware. In order to keep the moisture content of the air in a range which is expedient for drying, it is feasible, for example, to supply external room air to the drying zone 40 via an opening, for example through the outlet opening for the washware.

[0074] The warm and moisture-laden air in the drying zone 40 is then drawn off from the drying zone 40 via a further opening, for example with the aid of a fan 41. It is

advantageous here if the exhaust-air stream from the drying zone 40 passes a heat-recovery device 42 in which, for example, a condenser can be provided. The heat-recovery device 42 serves to recover at least some of the thermal energy contained in the exhaust air.

[0075] If, before initial starting of the conveyor dishwasher 2, the tanks (prewash tank 36, main wash tank 34, postwash tank 32) associated with the wash zones 12, 14 and 16 are empty or insufficiently filled, said tanks first have to be filled via a fresh water line 48 and/or by spraying final rinse liquid in the fresh water final rinse zone 18. The fresh water line 48 can be connected to a fresh water supply system by means of an actuable valve V3. The quantity of wash liquid available in the main wash zone 14 and in the prewash zone 12 can in each case be monitored and signaled to a control device 50 with the aid of a level sensor provided in the main wash tank 34 and with the aid of a level sensor provided in the prewash tank 36.

[0076] The fresh water final rinse zone 18 can - as illustrated in FIG. 1 - have an associated fresh water container 44 for temporarily storing at least a portion of the fresh water provided for final rinsing purposes. The fresh water container 44 is firstly provided with a fresh water connection which can be connected to a fresh water supply system by means of an actuable fresh water feed valve V2, and secondly is connected to the intake end of a final rinse pump 43. However, it goes without saying that it is also feasible to dispense with a fresh water container 44 for temporarily storing at least a portion of the fresh water provided for final rinsing purposes and to connect the fresh water feed valve V2 directly to the intake end of the final rinse pump 43.

[0077] It is not absolutely necessary to provide a final rinse pump 43 either. Instead, it is also possible, for example, to use the pressure from the fresh water line supply system in order to feed the fresh water which is to be sprayed in the fresh water final rinse zone 18 as final rinse liquid to the final rinse nozzles 20, 22, 24.

[0078] However, a final rinse pump 43, of which the delivery end is connected to a water heater 9 ("boiler") by means of a line system, is used in the conveyor dishwasher 2 schematically illustrated in FIG. 1. In this case, the line system is designed in such a way that the liquid delivered from the final rinse pump 43 to the spray nozzles 20, 22, 24 of the fresh water final rinse zone 18 first passes the heat-recovery device 42 in which at least some of the thermal energy from the exhaust air discharged from the conveyor dishwasher is used to heat up the liquid supplied to the spray nozzles 20, 22, 24 of the fresh water final rinse zone 18.

[0079] Rinse aid is added in a metered fashion with the aid of a rinse aid metering apparatus, which has a final rinse pump 6, to the fresh water which is supplied to the final rinse pump 43 either directly by the fresh water feed valve V2 or by the fresh water container 44. The rinse-aid metering apparatus is preferably arranged in such a way that rinse aid is added in a metered fashion to the fresh water in a position in which the fresh water has not yet been heated. In this context, experiments have shown that the rinse aid and fresh water mix significantly better and more uniformly when the rinse aid is added in a metered fashion to unheated fresh water.

[0080] Specifically, rinse aid should preferably be added in a metered fashion to fresh water which is at a temperature of less than 40°C, and preferably less than 30°C.

[0081] For this reason, rinse aid is added in a metered fashion between the final rinse pump 43 and the water heater 9 or the heat-recovery device 42 and the heat exchanger device 60 in the embodiment of the conveyor dishwasher 2 schematically illustrated in FIG. 1. The control device 50 of the conveyor dishwasher 2 is only schematically indicated in FIG. 1. A plurality of predefined or predefinable execution programs are preferably stored in the control device 50. To this end, the control device 50 has a corresponding memory device which, in this case, is preferably a random access memory (RAM). Each individual execution program defines the process parameters which are defined for treating the washware in the different treatment zones of the conveyor dishwasher 2 and include, in particular, the temperature, in particular minimum temperature, of the wash liquid which is to be sprayed in the prewash zone 12, of the wash liquid which is to be sprayed in the main wash zone 14, of the liquid which is to be sprayed in the postwash zone 16 and/or of the final rinse liquid which is to be sprayed in the fresh water final rinse zone 18.

[0082] To this end, it is preferred when a corresponding heating device 55, 56, 58 is arranged in the prewash tank 36 which is associated with the prewash zone 12, in the main wash tank 34 which is associated with the main wash zone 14 and/or in the postwash tank 32 which is associated with the postwash zone 16, in order to control the temperature of the liquid which is collected in the tank 32, 34, 36 in question in accordance with a selected execution program. Said heating devices 55, 56, 58 can be correspondingly actuated by the control device 50.

[0083] Furthermore, a heating device 57 of the water heater 9 can be correspondingly actuated by the control device 50 in order to adjust, as required, the temperature, in particular minimum temperature, of the final rinse liquid which is to be sprayed in the fresh water final rinse zone 18 if the temperature of the final rinse liquid which is to be sprayed is still not sufficiently controlled after passing the heat recovery device 42.

[0084] An exemplary embodiment of a cleaning system for automatically cleaning the interior of a dishwasher, in particular a dishwasher which is designed as a conveyor dishwasher, will be described in more detail below with reference to the illustration in FIG. 2. In detail, FIG. 2 shows a hydraulics diagram of the exemplary embodiment of the cleaning system according to the invention.

[0085] As indicated in FIG. 2, the cleaning system according to the invention is suitable, in particular, for implementation in a conveyor dishwasher which has various treatment zones which are arranged one behind the other as seen in the transportation direction 8 of the wash ware.

[0086] In line with the hydraulics diagram according to FIG. 2, the conveyor dishwasher 2 has a fresh water final rinse zone 18, a post- wash zone 16, a main wash zone 14, a prewash zone 12 and an inlet tunnel 10 in this exemplary embodiment.

[0087] The design and manner of operation of these treatment zones or regions has already been described with reference to the illustration in FIG. 1, and therefore these points will not be discussed in any detail here in order to avoid repetition. Instead, the description of the figures relating to the hydraulics diagram according to FIG. 2

concentrates on the design and manner of operation of the cleaning system according to the invention for automatically cleaning interiors.

[0088] However, it should be noted at this point that the final rinse system which is associated with the fresh water final rinse zone 18 is once again drawn in the hydraulics diagram according to FIG. 2.

[0089] This final rinse system has final rinse nozzles 20, 22 which are arranged in the fresh water final rinse zone 18 and are aimed at the washware (not illustrated in FIG. 2) which is to be subjected to final rinsing with fresh water in this treatment zone.

[0090] The fresh water final rinse nozzles 20, 22 can be flow-connected to a fresh water source by means of a line system (final rinse line system 60). A water heater 9 ("boiler") is provided in the final rinse line system 60 in order to heat the fresh water, which is to be sprayed by means of the fresh water final rinse nozzles 20, 22, to the desired process temperature. A heat recovery device 42 is provided downstream of the water heater 9. At least some of the thermal energy from the exhaust air discharged from the conveyor dishwasher 2 is used in this heat recovery device 42 to heat up the liquid supplied to the final rinse nozzles 20, 22 of the fresh water final rinse zone 18.

[0091] In the conveyor dishwasher 2 schematically illustrated in FIG. 2, the fresh water source has a fresh water supply system connection and a fresh water tank 44. The fresh water tank 44 is filled with fresh water from the fresh water supply system connection as required by actuating a corresponding valve V2. Said fresh water is either fresh water which has been directly drawn from the fresh water supply system connection, or correspondingly pretreated fresh water, in particular demineralized fresh water.

[0092] The fresh water tank 44 is flow-connected to the intake end of a feed pump (fresh water pump or final rinse pump 43). The delivery end of the final rinse pump 43 can be flow-connected to the final rinse line system 60 by means of a corresponding valve V4 which can be actuated by a control device 50, in order to be able to subject the washware in the fresh water final rinse zone 18 to final rinsing in the dishwasher mode of the conveyor dishwasher 2.

[0093] As is schematically indicated in FIG. 2, it is feasible in this context for a corresponding non-return valve V6 to be arranged between the delivery end of the final rinse pump 43 and the valve V4.

[0094] In the dishwasher mode of the conveyor dishwasher 2, the valve V4 is usually open, in order to supply, preferably continuously or as required, the fresh water final rinse nozzles 20, 22 with fresh water which has been correspondingly heated by means of the water heater 9 and/or the heat recovery device 42 before being sprayed in the fresh water final rinse zone 18.

[0095] In the cleaning mode of the conveyor dishwasher 2 however, it is provided that the valve V4 is closed, so that the flow connection between the fresh water final rinse nozzles 20, 22 and the fresh water source or the delivery end of the final rinse pump 43 is disconnected. The cleaning mode of the dishwasher usually takes place at the end of a working day, that is to say when the conveyor dishwasher 2 is not being used for cleaning washware.

[0096] As already stated at the outset, it is particularly necessary for the interior of the dishwasher to be carefully sprayed down with cleaning liquid, in particular fresh water, in the cleaning mode of the dishwasher 2. A large number of cleaning nozzles Rl to RIO, which are preferably in the form of rotary nozzles in order to enable the inner surfaces of the conveyor dishwasher 2 to be sprayed down but also to allow a condenser which forms part of the heat recovery device 42 to be rinsed off, are used for this purpose - as schematically indicated in FIG. 2.

[0097] Specifically, the valve V4 is closed and the delivery end of the final rinse pump 43 is flow-connected to the liquid inlet 71 of a liquid distributor 70 in order to clean the conveyor dishwasher 2, and in particular in order to clean the interior with the aid of the cleaning system according to the invention. A valve V5 which is provided between the liquid inlet 71 of the liquid distributor 70 and the delivery end of the final rinse pump 43 is opened for this purpose.

[0098] The liquid distributor 70 has, in addition to the abovementioned liquid inlet 71, a large number of liquid outlets (a total of seven liquid outlets 72 to 78 in the embodiment schematically illustrated in FIG. 2). In this case, the first liquid outlet 72 is flow-connected to a first cleaning nozzle arrangement by means of a first line system 82, wherein this first cleaning nozzle arrangement has the cleaning nozzles R9 and R10 which are arranged in the post-wash zone 16 and, respectively, in the main wash zone 14. The second liquid outlet 73 of the liquid distributor 70 is flow-connected to a second cleaning nozzle arrangement by means of a second line system 83, wherein this second cleaning nozzle arrangement has the cleaning nozzles Rl and R8 which are arranged in the prewash zone 12 and, respectively, in the inlet tunnel 10.

[099] The third liquid outlet 74 of the liquid distributor 70 is flow-connected to a third cleaning nozzle arrangement by means of a third line system 84, wherein the third cleaning nozzle arrangement comprises the cleaning nozzles R2 and R3 which are arranged in the upper region of the second main wash zone. [0100] The fourth liquid outlet 75 of the liquid distributor 70 is flow-connected to a fourth cleaning nozzle arrangement by means of a fourth line system 85, the cleaning nozzles R4 and R5 which are arranged in the main wash zone 14 (here: in the upper region) forming part of said fourth cleaning nozzle arrangement.

[0101] In the same way, the fifth liquid outlet 76 of the liquid distributor 70 is flow- connected to a fifth cleaning nozzle arrangement, comprising the cleaning nozzles R6 and R7, by means of a fifth line system 86. Here, the cleaning nozzle R6 is arranged in the post-wash zone 16, while the cleaning nozzle R7 is associated with the heat recovery device 42 for the purpose of cleaning the condenser.

[0102] As will be described in more detail below specifically with reference to the isometric exploded illustrations in FIGS. 3 A to 3D, the liquid distributor 70 is designed to sequentially establish a fluid connection between the liquid inlet and the individual liquid outlets 72 to 78 in accordance with a predefined sequence of events. The remaining liquid outlets 77 and 78 of the liquid distributor are not flow-connected to corresponding line systems in the hydraulics diagram illustrated in FIG. 2, but rather are correspondingly closed (for example with the aid of a blind cover or a blind pipe arrangement). A different number of cleaning nozzles may be necessary depending on the machine configuration, and therefore these liquid outlets 77, 78 which are closed in the hydraulics diagram according to FIG. 2 can have additional associated cleaning nozzle arrangements if required.

[0103] In this context, it is important that the liquid distributor 70 is designed to sequentially establish a fluid connection between the liquid inlet 71 and the individual liquid outlets 72 to 78 in the cleaning mode of the conveyor dishwasher 2. Sequentially establishing the fluid connection is necessary in as much as the capacity (throughflow rate and pressure) of the fresh water pump 43 is generally insufficient in order to supply liquid (fresh water) to all of the cleaning nozzles Rl to R10 at the same time, so that the cleaning nozzles Rl to R10 are to be actuated in groups, in particular in pairs, in a defined program sequence.

[0104] As will be explained in more detail below specifically with reference to the isometric exploded illustrations of an exemplary embodiment of the fluid distributor 70 according to the invention, the fluid distributor 70 takes on the task of sequentially supplying the various cleaning nozzle groups or cleaning nozzle pairs with liquid (fresh water). Specifically, the liquid distributor 70 is designed to sequentially flow-connect the individual liquid outlets 72 to 78 to the liquid inlet 71 of the liquid distributor, and therefore - at least in the cleaning mode of the dishwasher, that is to say when the valve V5 is open and the valve V4 is closed - to the delivery end of the final rinse pump 43. In this case, the liquid distributor 70 is designed to always advance by one position when a pressure fluctuation is generated in the system, and in particular at the liquid inlet 71 of the liquid distributor 70, in particular by the final rinse pump 43 being switched on and switched off. This pressure fluctuation at the liquid inlet 71 of the liquid distributor 70 causes the liquid distributor 70 to advance by one position and flow-connect the liquid inlet 71 of the liquid distributor 70 to a following liquid outlet. Therefore, all of the cleaning nozzle groups or cleaning nozzle pairs are actuated in succession by switching on and switching off the final rinse pump 43 several times.

[0105] In order that the control device 50 can identify the position of the liquid distributor 70 when operation is started, a position checking means is provided in the exemplary embodiment of the cleaning system according to the invention. Said position checking means is realized, in particular, by means of a magnetically operated reed contact. When operation is started, the final rinse pump 43 is switched off and switched on until the liquid distributor 70 has reached its starting position. This starting position is achieved when the reed contact is closed.

[0106] The design and the manner of operation of an exemplary embodiment of the liquid distributor 70 will be described in more detail below with reference to the isometric exploded illustrations according to FIGS. 3 A to 3D.

[0107] As can be seen, in particular, in the illustration in FIG. 3 A, the exemplary embodiment of the liquid distributor 70 according to the invention has a distributor housing 90 and a switching cylinder 91 which is accommodated in the distributor housing 90. In the illustrated exemplary embodiment, the distributor housing 90 is substantially made up of two housing parts, specifically a first housing region 90-1 and a second housing region 90- 2. The liquid inlet 71 of the liquid distributor 70 issues in the first housing region 90-1. The liquid outlets 72 to 78 of the liquid distributor 70 issue in the second housing region 90-2 which is arranged opposite the first housing region 90-1. As indicated in FIGS. 3 A to 3D, it is provided in this exemplary embodiment of the liquid distributor 70 that the liquid inlet 71 is provided on a first end side of the substantially cylindrical distributor housing 90, while the liquid outlets 72 to 78 are provided on a second end side of the distributor housing 90.

[0108] The abovementioned switching cylinder 91 is accommodated within the distributor housing 90. Specifically, it is provided in the exemplary embodiment of the liquid distributor 70 according to the invention shown in FIGS. 3 A to 3D that the switching cylinder 91 can not only be moved relative to the distributor housing 90 in the axial direction of the distributor housing 90, but rather also can be rotated relative to the distributor housing 90 about the longitudinal axis of the switching cylinder 91.

[0109] The switching cylinder 91 is specifically mounted in the distributor housing 90 in such a way that the said switching cylinder can be moved from a home position to a switching position in the direction of the second housing region 90-2 owing to the pressure of a liquid (in particular fresh water) which is fed into the first housing region 90-1 by means of the liquid inlet 71. As can be seen, in particular, in the isometric exploded illustration in FIG. 3 A, the exemplary embodiment of the liquid distributor 70 according to the invention further has a return mechanism in the form of a return spring 92. The return spring 92 serves to reset the switching cylinder 91 to its home position when the pressure of the liquid (fresh water) which is fed into the first housing region 90-1 falls below a predefined or predefinable value.

[0110] The switching cylinder 91 is designed, in particular in the exemplary embodiment shown in FIGS. 3 A to 3D, to rotate about its longitudinal axis by a predefined or predefinable angular value when it moves from the home position to the switching position and back. This has the effect that, for example owing to the final rinse pump 43 being switched on and switched off and owing to the resulting pressure fluctuation at the liquid inlet 71 of the liquid distributor 70, the switching cylinder changes its rotation position relative to the distributor housing 90, in particular relative to the second housing region 90- 2, with each (sufficient) pressure fluctuation. In this case, a fluid connection is established between the liquid inlet 71 and one of the various liquid outlets 71 to 78 of the liquid distributor 70 depending on the rotation position of the switching cylinder relative to the second housing region 90-2. [0111] As can be seen specifically in the detail shown in FIG. 3B in particular, the switching cylinder 91 in the exemplary embodiment of the liquid distributor 70 shown here has a first region, which faces the first housing region 90-1, and an opposite second region, which faces the second housing region 90-2, wherein a first tooth mechanism, which interacts with the first housing region 90-1, is associated with the first region of the switching cylinder 91, and a second tooth mechanism, which interacts with the second housing region 90-2, is associated with the second region of the switching cylinder 91. To this end, the switching cylinder 91 can - as indicated in FIGS. 3A to 3D - be of sleeve-like design at least in regions of its first and/or second region, wherein a corresponding toothed ring 93, 94 is formed in the sleeve-like region.

[0112] Secondly, serrations 95 which complement the toothed ring 93 are provided in the first housing region 90-1, and serrations 96 which complement the toothed ring 94 are provided in the second housing region 90-2. A mechanism which is usually called a "revolver" mechanism and is known as a latching-in mechanism for retractable ballpoint pens is implemented in the liquid distributor 70 in this way.

[0113] FIG. 3 A and FIG. 3D further indicate how a sensor device can be realized in order to detect that liquid outlet 72 to 78 of the liquid distributor 70 which forms a fluid connection with the liquid inlet 71 of the liquid distributor 70. Specifically, it is provided in the exemplary embodiment shown in FIGS. 3 A to 3D that the sensor device is designed to detect the rotation position of the switching cylinder 91 relative to the distributor housing 90. A corresponding reed sensor which is associated with the liquid distributor 70 is used for this purpose.

[0114] The functional description of the liquid distributor 70 according to the invention can therefore be summarized as follows:

[0115] The liquid distributor 70 is substantially composed of two housing parts (first housing region 90-1 and second housing region 90-2) comprising line connections, in particular hose connections, which define the liquid inlet 71 and the various liquid outlets 72 to 78 of the liquid distributor 70. Furthermore, a seal 97 is provided in order to be able to connect the two housing parts (first and second housing region 90-1 and 90-2) in a fluidtight manner. [0116] A movable switching cylinder 91 and a return spring 92 are provided within the distributor housing 90. Furthermore, it is advantageous when the liquid distributor 70 is provided with a reed contact and a corresponding magnet.

[0117] According to the preferred embodiment of the liquid distributor 70 according to the invention illustrated in the drawings, the liquid inlet 71 of the liquid distributor 70 is arranged on the end side of the first housing region 90-1, while the liquid outlets 72 to 78 are provided on the end side of the opposite second housing region 90-1. Both housing parts (first and second housing region 90-1, 90-2) are preferably screwed to one another and sealed off by the seal 97.

[0118] The switching cylinder 91 is pressed against the second housing region 90-2 by the liquid pressure which builds up. In this position, an overflow opening which is located in the switching cylinder overlaps with one of the liquid outlets 72 to 78 of the second housing region 90-2. The liquid (in particular fresh water) can therefore flow from the liquid inlet 71 to the corresponding liquid outlet 72 to 78 through the switching cylinder 91. If the liquid pressure at the liquid inlet 71 of the liquid distributor 70 drops, the switching cylinder 91 is pushed in the direction of the first housing region 90-1 by the return spring 92 which is tensioned between said switching cylinder and the second housing region 90-2.

[0119] Since both the inside of the first and second housing regions 90-1 and 90-2 and also the two end sides of the switching cylinder 91 each have a serrated shape (crown), the switching cylinder 91 rotates relative to the distributor housing 90 about its longitudinal axis (revolver principle) when it moves upward and downward. The geometry of the serrations 95, 96 which are provided in the housing regions 90-1 and 90-2 or the geometry of the serrations in the tooth borders 93, 94 is designed such that the overflow opening in the switching cylinder 91 precisely overlaps with the next liquid outlet of the large number of liquid outlets 72 to 78 after an upward and downward movement. The liquid distributor 70 can therefore be cyclically switched from one liquid outlet to the next liquid outlet owing to a pump being switched on and switched off or owing to the pressure fluctuation generated in this way. [0120] In order to ensure the chronology of the cleaning program, the respective liquid outlets 72 to 78 have to be switched in the correct order. When operation of the dishwasher 2 is started, the control device 50 (machine controller) therefore has to be able to identify the position of the switching cylinder 91 of the liquid distributor 70 and assume a defined starting position. This is realized by means of a magnetically operated reed contact which can be inserted into a bore or pocket 98 which is provided in the first housing region 90-1. During the machine start phase, the final rinse pump 43 is switched off and switched on until the magnet 99 which is located in the switching cylinder 91 closes the reed contact. The liquid distributor 70 or the switching cylinder 91 of the liquid distributor 70 has therefore reached its starting position.

[0121] Therefore, it is clear that a plurality of liquid outlets 72 to 78 can be cyclically switched, without electrical actuation, by the liquid distributor according to the invention, which is based on the revolver principle or the latching-in principle known from retractable ballpoint pens. The simple principle of the liquid distributor 70 allows, in particular, a compact and cost-effective construction.

[0122] The invention is not restricted to the exemplary embodiments illustrated in the drawings, but rather can be gathered by looking at all of the features disclosed in this application together.