EP2320785A1

EP2320785A1 - Dishwasher in the form of a programmable machine and method for operating it

Info

Publication number: EP2320785A1
Application number: EP09810453A
Authority: EP
Inventors: Udo Buerkle; Dominik Schneider
Original assignee: Premark FEG LLC
Current assignee: Premark FEG LLC
Priority date: 2008-08-29
Filing date: 2009-08-18
Publication date: 2011-05-18
Anticipated expiration: 2029-08-18
Also published as: WO2010025051A8; CA2732811A1; AU2009285959B2; CN106235979A; EP2320785B1; EP2320785A4; US20110132403A1; AU2009285959A1; CN102137613A; WO2010025051A1; DE102008044952A1

Abstract

The invention relates to a dishwasher (100) in the form of a programmable machine for the mechanical basic cleaning of washing stock and to a corresponding method for the cleaning of washing stock The method according to the invention comprises a cleaning phase, in which a cleaning fluid is sprayed out of a tank (4) in to a treatment chamber (2) through a line system (10) by means of a pump (8) and can flow back from the treatment chamber (2) into the tank (4) by gravity, and a πnsing phase, in which fresh water is sprayed as πnsing fluid in to the treatment chamber (2) through a πnsmg-line system (15) by means of a πnsing pump (12) and can flow from the treatment chamber (2) in to the tank (4) by gravity

Description

DISHWASHER IN THE FORM OF A PROGRAMMABLE MACHINE AND METHOD FOR OPERATING IT

The invention relates to a method for the cleaning of washing stock and, in particular, to a commercial dishwasher which is designed in the form of a programmable machine.

Dishwashers according to the invention are programmable machines. These may be basket push-through machines or front loaders, in particular under-counter machines. In hand-fed programmable machines, the washing stock, which is preferably received in a utensil basket, is manually introduced into and removed from the machine either via a front door or, in the case of basket push-through machines, via a counter delivery.

A particular type of commercial dishwashers in the form of programmable machines is hood-type machines. Their treatment chamber for the cleaning of washing stock is surrounded by a hood. The hood can be raised upwards in order to load the treatment chamber and can then be lowered again for the treatment of the washing stock. Hood-type machines are provided, almost without exception, with a run-in table and a run-out table.

Commercial dish or utensil washers which are designed as a programmable machine normally operate in two main process steps, to be precise, first, cleaning with a cleaning fluid (cleaning phase) and then rinsing with heated or unheated rinsing fluid (rinsing phase) .

In programmable machines, the two main process steps, the "cleaning phase" and the "rinsing phase", take place successively in time, but not in a spatially separated way, in one zone (treatment chamber) . As a rule, beneath the treatment chamber, a tank is arranged, in which fluid sprayed in the treatment chamber can flow back by gravity. Furthermore, a dishwasher designed as a programmable machine usually has a cleaning system with a pump, with a line system connected to the pump and with cleaning nozzles. The fluid (cleaning fluid or detergent solution) contained in the tank arranged beneath the treatment chamber can be conveyed to the cleaning nozzles by the pump via the line system and be sprayed in the treatment chamber by the cleaning nozzles onto the washing stock or ware to be cleaned. As already indicated, the sprayed cleaning fluid subsequently flows back into the tank arranged beneath the treatment chamber.

Moreover, a commercial dishwasher designed as a programmable machine is normally equipped with two fluid systems which are independent of one another and are separated completely from one another. One of these two fluid systems is a cleaning- fluid circuit, in which, for the purpose of cleaning the washing stock, a circulation of the cleaning fluid from the tank already mentioned is carried out. The other fluid system is a rinsing-fluid system which may have a water heater for the heating of fresh water.

The main object of rinsing with rinsing fluid is to remove the cleaning fluid (lye) still located on the washing stock after the cleaning phase. The rinsing fluid preferably used is therefore fresh water, to which a rinse aid can be added. In addition, the rinsing fluid flowing off in to the tank during rinsing serves for regenerating the cleaning fluid received in the tank arranged beneath the treatment chamber, since the rinsing fluid (pure fresh water or fresh water mixed with rinse aid) sprayed in the treatment chamber during the rinsing phase flows by gravity in to the tank arranged beneath the treatment chamber. Before new rinsing fluid passes into the tank in this way during the rinsing phase in order to regenerate the cleaning fluid, the same quantity of cleaning fluid is pumped off from the tank.

Usually, a detergent or a detergent combination is added to the cleaning fluid which is sprayed in the treatment chamber during the cleaning phase. When the dishwasher is operating normally, during which standard washing-stock cleaning is carried out, the cleaning fluid contains a standard detergent, that is to say a detergent which, by virtue of its chemical composition, makes it easier to release food residues from the washing stock during the cleaning phase. Furthermore, a standard detergent often has the capability of finely distributing and suspending food residues in the cleaning fluid (anti-redeposition capacity) , with the result that a resoiling of the washing stock while the cleaning fluid is recirculating during the cleaning phase can be counteracted.

For the mechanical cleaning of washing stock, various detergents or detergent compositions are offered, which can be optimized in terms of the material of the washing stock to be cleaned. There are special standard detergents particularly for the mechanical cleaning of glasses and cellulose nitrate containers.

When the dishwasher is operating normally, that is to say when standard washing-stock cleaning is carried out with a normal standard detergent or with a standard detergent adapted to the type of washing stock, however, it is often not possible to prevent (slight) residues, which cannot be removed by means of standard cleaning, from still remaining on the surfaces of the washing stock. This includes, for example, what is known as the starch build-up, which is a type of soiling which may arise when starch-containing food (such as, for example, sauces, mashed potato, etc.) are served on preheated plates. On the other hand, however, lime or protein deposits may also lead to residues which, when the dishwasher is operating normally, cannot be removed completely from the surface of the washing stock. As already indicated, as a rule, this type of soiling cannot be removed by means of a cleaning program carried out, as standard, by the dishwasher, and therefore, after a lengthy use of the washing stock, a cumulative build-up of residues on the surfaces of the washing stock cannot be avoided.

In order to remove these residues, a basic cleaning of the washing stock is regularly carried out. The term "basic cleaning" is to be understood as meaning an occasional or, if necessary, initial process of cleaning the washing stock, using suitable treatment agents (basic detergents) , in which built-up coatings, in particular starch, protein or lime, are removed.

Conventionally, during basic cleaning, the washing stock to be treated is introduced in to an immersion basin which contains a basic cleaning fluid. The basic cleaning fluid, as a rule, has a high-dose treatment agent (basic detergent) . After a defined softening time in the basic cleaning fluid, the washing stock is cleaned manually. After cleaning, the washing stock is rinsed off with fresh water, in order to rinse off residues of the basic detergent from the surface of the washing stock completely. Manual basic cleaning is therefore labour-intensive and time-consuming manual work.

The invention is to achieve the object of providing a possibility whereby a saving of time and of cost can be achieved during the basic cleaning of washing stock.

The solution according to the invention is distinguished in that a dishwasher designed as a programmable machine is designed for executing different treatment programs, while, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out, the treatment parameters of the cleaning phase and the treatment parameters of the rinsing phase are automatically set in adaptation to one another. The solution according to the invention is thus distinguished, in particular, in that the treatment parameters of the cleaning phase and of the rinsing phase can be adapted optimally not only during standard cleaning, but also during a basic cleaning of the washing stock, in order to allow a treatment of the washing stock which is optimized in terms of a cleaning task. Accordingly, the dishwasher according to the invention is designed such that it can not only execute mechanical standard cleaning, particularly for the removal of food residues, but, if required, also execute mechanical basic cleaning, in order to remove coatings, in particular starch, protein or lime, which have accumulated in the course of time.

For this purpose, the dishwasher according to the invention has a program control device, by means of which, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out, the treatment parameters of the cleaning phase and the treatment parameters of the rinsing phase are automatically set in adaptation to one another. Since, in the solution according to the invention, the respective treatment parameters of the cleaning phase and rinsing phase are set in adaptation to one another, it is possible to coordinate optimally with one another the interaction at least of the factors which influence the cleaning result to the greatest extent. These factors include, in particular, the temperature of the cleaning fluid recirculating during the cleaning phase, the contact time between the cleaning fluid and the washing stock to be cleaned, the nozzle pressure used during the spraying of the cleaning fluid, and the quantity of rinsing fluid sprayed during the rinsing phase. By the treatment parameters being coordinated automatically, an overtreatment of the washing stock during the cleaning and the rinsing phase can be effectively prevented.

The cleaning phase carried out by the programmable machine takes place according to a cleaning program adapted to the cleaning task, so that the temperature of the cleaning fluid, the contact time between the cleaning fluid and the washing stock and/or the nozzle pressure used during the spraying of the cleaning fluid can be optimized, and this can lead to savings of time and of cost. Moreover, the quantity of rinsing fluid sprayed overall during the rinsing phase is adapted to the demand actually required, and therefore, here too, fresh water and, if appropriate, energy can be saved.

The solution according to the invention is therefore also suitable, for example, for executing a mechanical basic cleaning of washing stock, an overtreatment of the washing stock during the cleaning and rinsing phase being effectively prevented, and therefore an optimal cleaning result being achievable, while at the same time there is a saving of time and of cost.

Preferably, the solution according to the invention can be implemented in the form of a commercial programmable machine which is designed for executing a special basic-cleaning program for the basic cleaning of washing stock. This basic- cleaning program may, for example, be stored in a memory of a program control device as an additional cleaning program, together with one or more standard-cleaning programs and be retrieved, as required, by the operator of the dishwasher. For the additional basic-cleaning program, the parameters and program sequences which differ from a standard-cleaning program are fixed, in order to achieve the efficiency which is required for the removal of, for example, a cumulative starch build-up. After the use of this program, there can be a direct changeover again from the basic-cleaning program to a standard-cleaning program.

The invention is described below by means of a preferred embodiment, as an example, with reference to the accompanying drawing in which:

Fig. 1 shows diagrammatically a dishwasher, in particular a commercial dishwasher, in the form of a programmable machine according to an embodiment of the invention. The dishwasher 100, illustrated as an example in Fig. 1, contains a treatment chamber 2 for the cleaning of washing stock, not shown. Beneath the treatment chamber 2, a tank 4 is arranged, in which fluid can flow back from the cleaning chamber 2 by gravity. The tank 4 may be covered at the transition to the treatment chamber 2 with a screen, not illustrated in Fig. 1.

The tank 4 contains cleaning fluid which is usually water, to which a detergent can be supplied either automatically by a detergent metering device, not illustrated explicitly in Fig. 1, or manually. The type, that is to say the chemical composition, and the quantity of the added detergent may be dependent on the type and/or the degree of soiling of the washing stock to be cleaned in the dishwasher 100. Thus, for example, it is conceivable that, for a mechanical cleaning of glasses, a standard detergent optimized for this purpose is used, the chemical composition of which is adapted to the material of the washing stock (glass) and/or to the degree of soiling to be expected in this type of washing stock.

The cleaning fluid can be conveyed to cleaning nozzles 7 and 9 by a pump 8 via a line system 10 and be sprayed in the treatment chamber 2 through these cleaning nozzles 7, 9 on to the washing stock to be cleaned. The sprayed cleaning fluid subsequently flows back in to the tank 4. A discharge line 3 having an outflow pump 11 may be connected to the lower end 5 of the tank 4, in order, as required, to empty the tank 4 completely or partially.

In the embodiment of the dishwasher 100 according to the invention, as illustrated in Fig. 1, a rinsing pump 12 is connected with its suction side to an outlet 35 of a water heater 20. The water heater 20 has an inlet 22 connected to a fresh-water supply line 28. The fresh-water supply line 28 can be connected to further fresh-water supply lines 24, 26 via a valve 27, so that either fresh water or fresh water with added rinse aid can be supplied to the water heater 20. The water heater 20 has a heating arrangement 21, so that the fluid (pure fresh water or fresh water with added rinse aid) supplied via the inlet 22 can be heated up according to the stipulation of a process sequence. Via the rinsing pump 12 connected with its suction side to the outlet 35 of the water heater 21, the rinsing fluid selectively heated up or not heated up in the water heater 20 can be routed, for example during a rinsing phase, to rinsing nozzles 33 and 34 via a rinsing-line system 15. The rinsing nozzles 33 and 34 are arranged in the treatment chamber 2, in order to spray the rinsing fluid heated in the water heater 20 on to the washing stock in the treatment chamber 2. It is, of course, also conceivable, however, that the water heater 20 is supplied via the inlet 22 and the fresh-water supply line 28 with pure fresh water to which a rinse aid is added only after heating in the water heater 20.

The solution according to the invention is not restricted to the presence of a water heater 20. Instead, within the scope of the invention, the provision of a water heater 20 may even be dispensed with, so that unheated rinsing fluid is conveyed to the rinsing nozzles 33 and 34 arranged in the treatment chamber 2 and is sprayed on to the washing stock.

In the embodiment, illustrated diagrammatically in Fig. 1, of the dishwasher 100 according to the invention, the cleaning nozzles 7, 9 and the rinsing nozzles 33, 34 are in each case arranged preferably above and below the washing-stock region and are directed towards the washing-stock region of the treatment chamber 2. In particular, in the embodiment illustrated, an upper cleaning-nozzle system directed downwards and an upper rinsing-nozzle system formed separately from this and likewise directed downwards and also a lower cleaning-nozzle system directed upwards and a lower rinsing-nozzle system formed separately from this and likewise directed upwards are provided. It is, of course, also conceivable, however, to provide an upper and a lower cleaning-nozzle system which serve jointly for the spraying of cleaning fluid (during a cleaning phase) and for the spraying of rinsing fluid (during a rinsing phase) . Also, the cleaning nozzles 7, 9 and/or the rinsing nozzles 33, 34 may be arranged only at the top or only at the bottom, instead of at the bottom and at the top, or, instead or additionally, may also be arranged on one side of the treatment chamber 2 and be directed in to the washing-stock region transversely to the treatment chamber 2.

In the embodiment of the dishwasher 100, as illustrated in Fig. 1, the water heater 20 is connected to a suck-back preventer 16 via fresh water supply lines 24, 26, and 28. The suck-back preventer 16 prevents the situation where fresh water may be sucked back from the suction side of the rinsing pump 12 in to a fresh-water supply line 17 connectable, for example via a valve 19, to a fresh-water network.

As illustrated in Fig. 1, the suck-back preventer 16 may have an outlet 40 which is connected to a water softener device 39 via fresh-water supply lines 24 and 41. The water softener device 39 may have, on the one hand, a salt container 42 connected to the fresh-water supply line 41 and, on the other hand, first and second water softeners 39a, 39b arranged parallel to one another. The two water softeners 39a, 39b arranged parallel to one another may be connected to the outlet 40 of the suck-back preventer 16 via the fresh-water supply line 24 already mentioned.

It is conceivable that the water softeners 39a, 39b of the water softener device 39 can be operated alternately by means of the suitable activation of valves 43, in order to soften the fresh water supplied to the water heater 20 via the fresh-water supply lines 26 and 28. The salt container 42 belonging to the water softener device 39 contains a suitable salt or a suitable chemical, by means of which, as required, a water softening agent added via the water softeners 39a and 39b or a decomposition product occurring during the addition of a water softening agent can be suitably regenerated. The salt container 42 can be topped up with the salt or the chemical from the treatment chamber 2 via a port closable by means of a lid 44.

A program control device 50 for controlling at least one cleaning program is connected to the activatable components of the dishwasher 100, in order to carry out a cleaning program selected by the operator of the dishwasher 100. In the embodiment illustrated in Fig. 1, the program control device 50 is connected , for example, to the valves 19 and 27, to the pump 8, to the rinsing pump 12 and/or to a heating control circuit for controlling the heating arrangement 21 of the water heater 20.

In particular, the program control device 50 is designed to implement a cleaning method (cleaning cycle) having the following steps (phases) to be executed in succession:

a) a cleaning phase, in which a detergent solution is sprayed from a tank 4 through the line system 10 into the treatment chamber 2 by means of the pump 8 and can flow back from the treatment chamber 2 in to the tank 4 by gravity; and

b) a rinsing phase, in which fresh water is sprayed as rinsing fluid in to the treatment chamber 2 through the rinsing-line system 15 by means of the rinsing pump 12 and can flow from the treatment chamber 2 in to the tank 4 by gravity.

The solution according to the invention is distinguished in that the program control device 50 is designed, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out, for automatically setting the treatment parameters of the cleaning phase and the treatment parameters of the rinsing phase in adaptation to one another. For this purpose, it is conceivable that the treatment parameters characteristic of the execution of various cleaning programs are stored in the program device 50 or in a memory device, not illustrated in Fig. 1, to which the program control device 50 can have access. The treatment parameters belonging to a cleaning program define the essential factors in the treatment of the washing stock during the cleaning phase and in the treatment of the washing stock during the rinsing phase.

It is essential that the dishwasher 100 according to the invention is designed not only for the mechanical execution of a cleaning program (standard-cleaning program) executable by a conventional programmable machine, but also for the mechanical execution, in particular, of a basic-cleaning program. As already indicated, it is usually not possible, by means of a standard-cleaning program, effectively to prevent the build-up of starch, protein and/or lime deposits on the surface of the washing stock to be cleaned or even to remove an already existing starch, protein and/or lime build-up. To eliminate this type of soiling, it is necessary, for example, that, during basic cleaning, in the cleaning phase the contact time between the cleaning fluid enriched with a detergent and the washing stock to be cleaned is prolonged and/or that the temperature of the cleaning fluid is increased.

Accordingly, in the dishwasher 100 illustrated by way of example in Fig. 1 and designed as a programmable machine, preferably, for a stipulated treatment program selectable by the operator of the dishwasher 100, the temperature of the cleaning fluid to be sprayed during the cleaning phase and/or the contact time between the cleaning fluid and the washing stock to be cleaned are coordinated with one another and predetermined .

Moreover, it is preferable if, in the dishwasher 100 designed as a programmable machine, in addition, the nozzle pressure used during the spraying of the cleaning fluid and the quantity of rinsing fluid sprayed during the rinsing phase are predetermined.

These parameters defining the treatment of the washing stock during the cleaning and the rinsing phase are in this case coordinated with one another such that, after a treatment program has been carried out, a cleaning task stipulated by the operator of the dishwasher 100 is fulfilled, without an overtreatment of the washing stock occurring during the cleaning and the rinsing phase. The term "stipulated cleaning task" includes here both a standard cleaning, which involves a mechanical standard cleaning of washing stock, that is to say the mechanical cleaning of washing stock according to a standard treatment program, and a mechanical basic cleaning, in which coatings accumulated in the course of time, in particular starch, protein and/or lime coatings, which cannot or cannot completely be eliminated during mechanical standard cleaning, are removed from the surface of the washing stock.

The treatment parameters for the cleaning phase of a basic- cleaning program which can be carried out mechanically by the dishwasher 100 differ from the treatment parameters of the cleaning phase of a standard-cleaning program, particularly with regard to the temperature of the cleaning fluid sprayed during the cleaning phase and/or with regard to the contact time between the cleaning fluid and the washing stock to be cleaned. In particular, preferably, at least one of the two parameters, "temperature of the cleaning fluid" or "contact time between the cleaning fluid and the washing stock", assumes a higher value, as compared with the corresponding treatment parameter of a standard-cleaning program, in order thereby to achieve an efficient removal of, for example, a cumulative starch build-up.

So that the treatment parameters for the cleaning phase can be set in order to implement a basic-cleaning program, the dishwasher 100 according to the invention may have a tank heating arrangement, not illustrated in Fig. 1. The tank heating arrangement may be designed, for example, as a heating element which is arranged in the tank 4 in order to heat the cleaning fluid to be sprayed during the cleaning phase. Preferably, in this case, the tank heating arrangement can be activated by the program control device 50 in such a way that a stipulated temperature of the cleaning fluid is set automatically in accordance with the treatment parameters of a selected cleaning program and therefore depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out. It is, of course, also conceivable, however, that a heating device is provided, for example in the line system 10 between the pump 8 and the cleaning nozzles 7, 8.

Alternatively or additionally to a tank heating arrangement activatable by the program control device 50, it is preferable if, with the aid of the program control device 50, the quantity of cleaning fluid recirculating during the cleaning phase can be set automatically in accordance with the treatment parameters of a selected cleaning program and therefore depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out. This may be implemented, for example, by means of an activation of the pump 8 which is carried out according to a program sequence.

As expounded above, during basic cleaning, a starch, protein and/or lime build-up on the surface of washing stock can be removed, in that, with the aid of the program control device 50, for example, the cleaning fluid recirculating during the cleaning phase is heated to a higher temperature, as compared with standard treatment and/or in that, for example, by a suitable activation of the pump 8, the contact time between the cleaning fluid and the surface of the washing stock (or the duration of the cleaning phase and the quantity of cleaning fluid circulated overall during the cleaning phase) is increased, as compared with standard treatment.

Alternatively or additionally to these measures, however, it is also conceivable that a basic cleaning of the washing stock is carried out by increasing the detergent concentration in the cleaning fluid. In the dishwasher 100 according to the invention, therefore, it is preferable if not only the temperature of the cleaning fluid recirculating during the cleaning phase and the contact time between the cleaning fluid and the washing stock, but also the type and/or concentration of the detergent added to the cleaning fluid are selected as a function of the cleaning task and, in particular, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out. The detergent may in this case be added to the cleaning fluid either automatically with the aid of a detergent metering device, preferably activatable by the program control device 50, or manually.

Irrespective of the concentration of the detergent added to the cleaning fluid, in each program sequence care must be taken, during the rinsing phase to be carried out after the cleaning phase, to ensure that all detergent residues are rinsed off from the surface of the washing stock. If, for the basic cleaning of the washing stock, the concentration of the detergent added to the cleaning fluid is increased, as compared with the detergent concentration during standard cleaning, the quantity of the rinsing fluid sprayed overall during the rinsing phase must also be increased, so that a sufficient rinsing result can be achieved. For this reason, in the dishwasher 100 according to the invention, the program control device 50 should be designed to set automatically, as a function of the concentration of a detergent added to the cleaning fluid, the quantity of rinsing fluid sprayed overall during the rinsing phase.

In a preferred implementation of the solution according to the invention, there is provision for the program control device 50 to be connected, for example, to the rinsing pump 12 and to be designed, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out, for automatically setting the quantity of rinsing fluid sprayed overall during the rinsing phase, the quantity of rinsing fluid sprayed overall during the rinsing phase being increased automatically when a basic cleaning of the washing stock is carried out instead of a standard cleaning. In this implementation, it is assumed that, for the basic cleaning of the washing stock, the concentration of a detergent added to the cleaning fluid is also increased. The quantity of rinsing fluid sprayed overall during the rinsing phase is set by the program control device 50 as a function of the type of cleaning to be carried out, in order thereby to prevent an overtreatment of the washing stock during the rinsing phase and therefore an increased consumption of fresh water and, if appropriate, of energy which has to be expended in order to heat the rinsing fluid.

The rinsing fluid sprayed during the rinsing phase may be fresh water or fresh water mixed with rinse aid. The task of the rinse aid is to relieve the surface tension of the fresh water used for rinsing and, by lowering the interfacial tension, to achieve an optimal wetting of the washing stock to be rinsed in the rinsing phase.

In summary, it remains to be pointed out that, according to the invention, an, in particular, commercial dishwasher is specified, which is designed not only for mechanical standard cleaning, but also for mechanical basic cleaning of washing stock, while, depending on which cleaning task is selected by the operator of the dishwasher, treatment parameters optimally coordinated with one another are selected and set automatically for the cleaning and the rinsing phase.

It is conceivable, for example, that at least one basic- cleaning program is stored, in addition to at least one standard-cleaning program, in the program control device 50. For the additional basic-cleaning program, the program parameters which differ from the program parameters of a standard-cleaning program are fixed, in order to achieve the efficiency which is required for the removal of, for example, a starch, protein and/or lime build-up. After the use of this program, there can be a direct changeover from the basic- cleaning program to a standard-cleaning program again.

The program control device 50 used in the solution according to the invention is preferably designed for implementing the following program sequence:

When the basic-cleaning program is started from a standard operation of the dishwasher 100, then, first, part or all of the cleaning fluid (washing lye) is emptied out of the tank 4 and replaced with fresh water. A suitable detergent is added to the fresh water. The chemical used as detergent may be introduced manually or automatically, as a liquid or a powder, in to the fluid received in the tank 4, in order to raise the basic dosage of the fluid to a desired pH value. The temperature of the cleaning fluid (fresh water with added detergent) is subsequently adapted to the optimal effectiveness of the detergent chemical used.

The quantity of cleaning fluid recirculating during the cleaning phase is set such that an optimal cleaning result is achieved and, nevertheless, the chemical consumption remains as low as possible. The duration for which the washing stock is sprayed with cleaning fluid during the cleaning phase is adapted to the desired cleaning result, so that, for example, even in the case of washing stock with a high starch buildup, the desired cleaning result can be achieved.

After the cleaning phase, the quantity of rinsing fluid introduced during the subsequent rinsing phase is previously pumped off from the tank 4, in order, after the rinsing phase, to have the starting quantity of cleaning fluid available again in the tank 4.

After a defined dripping time, the washing stock is sprayed with an adapted quantity of rinsing fluid during the rinsing phase, in order to remove the cleaning fluid from the surface of the washing stock.

The end of the program sequence may be indicated by means of an optical or acoustic signal, and the washing stock may then be removed from the dishwasher 100.

When a new basic-cleaning program is started, the detergent concentration, reduced by pumping-off and rinsing, in the cleaning fluid is restored to the starting level. For this purpose, the necessary fraction of the chemical used is introduced manually or automatically, as liquid or powder, in to the cleaning fluid.

When a standard-cleaning program is selected after the basic- cleaning program, the entire cleaning fluid is pumped off from the tank 4. The tank 4 is subsequently refilled with fresh water, and a standard detergent is added again.

The invention is not restricted to the embodiment shown by way of example in Fig. 1. On the contrary, the invention arises from an overall consideration of the patent claims and of the description by a person skilled in the art.

Claims

Patent Claims

1. Method for the cleaning of washing stock in a commercial dishwasher (100) which is configured as a programmable machine, containing the following program-controlled method steps to be executed in succession: a) a cleaning phase, in which a cleaning fluid is sprayed from a tank (4) in to a treatment chamber (2) through a line system (10) by means of a pump (8) and can flow back from the treatment chamber (2) in to the tank (4) by gravity; and b) a rinsing phase, in which fresh water is sprayed as rinsing fluid in to the treatment chamber (2) through a rinsing-line system (15) by means of a rinsing pump

(12) and can flow from the treatment chamber (2) in to the tank (4) by gravity, characterized in that, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out, the treatment parameters of the cleaning phase and the treatment parameters of the rinsing phase are automatically set in adaptation to one another.

2. Method according to Claim 1, in which the cleaning fluid is fresh water with added detergent, characterized in that the type of detergent added to the fresh water and/or the detergent concentration in the cleaning fluid depends on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out.

3. Method according to Claim 1 or 2, in which heated cleaning fluid is sprayed during the cleaning phase, characterized in that the temperature of the cleaning fluid is set automatically, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out.

4. Method according to Claim 3, characterized in that the temperature of the cleaning fluid is increased automatically when a basic cleaning of the washing stock is carried out instead of a standard cleaning.

5. Method according to one of the preceding claims, characterized in that the time of action between the cleaning fluid and the washing stock to be cleaned is set automatically, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out.

6. Method according to Claim 5, characterized in that the time of action between the cleaning fluid and the washing stock to be cleaned is increased automatically when a basic cleaning of the washing stock is carried out instead of a standard cleaning.

7. Method according to one of the preceding claims, characterized in that the nozzle pressure used in the spraying of the cleaning fluid during the cleaning phase is set automatically, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out .

8. Method according to Claim 7, characterized in that the nozzle pressure used in the spraying of the cleaning fluid during the cleaning phase is increased automatically when a basic cleaning of the washing stock is carried out instead of a standard cleaning.

9. Method according to one of the preceding claims, characterized in that the quantity of rinsing fluid sprayed overall during the rinsing phase is set automatically, depending on whether a standard cleaning or basic cleaning of the washing stock is to be carried out .

10. Method according to Claim 9, characterized in that the quantity of rinsing fluid sprayed overall during the rinsing phase is increased automatically when a basic cleaning of the washing stock is carried out instead of a standard cleaning.

11. Method according to one of the preceding claims for carrying out a plurality of successive basic-cleaning cycles for the basic cleaning of washing stock, each basic-cleaning cycle having a cleaning phase and a rinsing phase following this, characterized in that, before the start of the cleaning phase of the first basic-cleaning cycle, the tank (4) is filled with a reduced quantity of fluid, as compared with the overall capacity of the tank (4), and in that, before the start of the cleaning phase of each basic-cleaning cycle, a quantity of basic detergent adapted to the fluid quantity received in the tank (4) is added in such a way that, during the cleaning phase of each basic-cleaning cycle, the basic-detergent concentration in the cleaning fluid sprayed during the cleaning phase is constant.

12. Commercial dishwasher (100) in the form of a programmable machine, which has the following: a program control device (50) for executing a selected cleaning program; a treatment chamber (2), in to which washing stock can be inserted and can be removed manually; a tank (4), in to which fluid from the treatment chamber (2) can flow by gravity; a cleaning system (7, 8, 9, 10) with a pump (8) and with a line system (10) for the conveyance of cleaning fluid during a cleaning phase out of the tank (4) through cleaning nozzles (7, 9) in to the treatment chamber (2); and a rinsing system (12, 15, 33, 34) with a rinsing pump (12) and with a rinsing-line system (15) for the conveyance of rinsing fluid during a rinsing phase through rinsing nozzles (33, 34) in to the treatment chamber (2) , characterized in that the program control device (50) is designed, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out, automatically to set the treatment parameters of the cleaning phase and the treatment parameters of the rinsing phase in adaptation to one another.

13. Dishwasher (100) according to Claim 12, in which, furthermore, a heating arrangement for the heating of the cleaning fluid to be sprayed during the cleaning phase is provided, characterized in that the heating arrangement can be activated by the program control device (50) in such a way that a temperature of the cleaning fluid is set automatically, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out.

14. Dishwasher (100) according to Claim 12 or 13, characterized in that the program control device (50) is designed, depending on whether a standard cleaning or a basic cleaning of the washing stock is to be carried out, for automatically setting the nozzle pressure used in the spraying of the cleaning fluid during the cleaning phase.

15. Dishwasher (100) according to one of Claims 12 to 14, characterized in that the program control device (50) is designed, depending on whether a standard cleaning or basic cleaning of the washing stock is to be carried out, for automatically setting the quantity of rinsing fluid sprayed overall during the rinsing phase.

6. Dishwasher (100) according to one of Claims 12 to 15, characterized in that the program control device (50) is designed for automatically increasing the quantity of rinsing fluid sprayed overall during the rinsing phase, when a basic cleaning of the washing stock is carried out by the dishwasher (100) instead of a standard cleaning; and/or in that the program control device (50) is designed for automatically increasing the temperature of the cleaning fluid recirculating during the cleaning phase, when a basic cleaning of the washing stock is carried out by the dishwasher (100) instead of a standard cleaning; and/or in that the program control device (50) is designed for automatically increasing the nozzle pressure used in the spraying of the cleaning fluid during the cleaning phase, when a basic cleaning of the washing stock is carried out by the dishwasher (100) instead of a standard cleaning.