EP2217124B1 - Dishwashing machine and method for the operation thereof - Google Patents

Description

The invention relates to a dishwasher, in particular a commercial dishwasher, and a method for its operation.

Dishwashing machines (warewashers), especially commercial dishwashing machines, in the form of box-type warewashers may be hood-type warewashers or frontloader warewashers.

A dishwasher (box-type warewasher) and several methods of its operation are for example from the WO 2006/129963 A2 known. It is provided with a steam generator for the treatment of the dishes with steam during different process cycles. The use of steam is provided before a wash cycle or after a wash cycle. The treatment of dishes by steam between a pre-cleaning cycle and a main cleaning cycle is also from the DE 29 00 954 A1 known.

From the EP 0 808 894 B1 a method is known according to which the items to be washed are sprayed with a detergent solution during a pre-cleaning cycle, before a main cleaning cycle and then a final rinse cycle take place. The spraying of dishes with a highly concentrated alkaline detergent solution is also from the EP 1 347 039 B1 known.

From the WO 2006/037447 A1 a dishwashing machine is known in which wash ware cleaned with washing liquid, then rinsed with fresh water, and then subjected to a thermal aftertreatment with steam.

Since washware is usually not only dishes such as plates and cups, but also cutlery such as spoons, forks and knives, as well as other utensils such as trays, pots and pans, dishwashers, especially commercial dishwashers, also referred to as utensil washers (warewashers).

Commercial dishwashing machines normally operate in two main process steps: a first step involving washing with a washing liquid and a second step involving rinsing with heated fresh water and dosed rinse aid.

In order to carry out these process steps, a commercial dishwasher is usually equipped with two independent liquid systems, which are completely separated from each other. The one fluid system is a wash water circuit, which is responsible for the washing of the items to be washed, wherein the washing is carried out with recirculated water from a wash tank. The other liquid limb system is a fresh water system, which is responsible for the rinse. The rinse is done with fresh water, preferably with fresh water from a water heater (boiler). The fresh water is also absorbed by the wash tank after spraying.

The main task of rinsing is to remove lye on the dishes. In addition, the rinse water flowing into the wash tank during the rinse step serves to regenerate the wash water present in the wash tank.

Before fresh water is sprayed through the rinse as final rinse liquid and thereby passed into the wash tank, one of the fresh water amount of the same amount of washing liquid is pumped out of the wash tank.

Today's dishwashers are equipped with several programs. These programs differ mainly by different long program durations of the washing process step. The customer has the option to choose a short wash program for slightly soiled dishes or to select a correspondingly longer washing program for heavily soiled dishes.

Special in commercial dishwashers or utensil washers is the Spülgutantell, which is heavily contaminated, for example, contains burned food remains, often very high. Since in such dishwashers, for example, also cookware, warming boxes or baking pans and baking trays are cleaned with burnt food residues, such items must be pre-cleaned or cleaned in many cases, since the "normal" machine cleaning even with longer periods of programs is not able to to achieve a satisfactory cleaning result.

The aim of the invention is to provide a way by which the cleaning process can be reduced in an ergonomic and environmentally friendly manner.

This object is achieved according to the invention by the features of claim 1 and a correspondingly designed dishwasher or utensil dishwasher.

The invention precedes the washing cycle with two process steps, in which soft water vapor is used in combination with a highly concentrated alkaline cleaning solution for soaking contaminants on the items to be washed, in particular soiling in the form of food residues or other food residues.

The highly concentrated alkaline cleaning solution is sprayed onto the items in the treatment chamber of the dishwasher or the utensil dishwasher. During the subsequent exposure cycle, an exposure time is integrated into the program sequence during which the highly concentrated alkaline detergent solution can act on the dishes and during which additional steam is introduced into the treatment chamber, e.g. B. in the Spülgutbereich and there is sprayed on the dishes.

By combining the simultaneous action of highly concentrated, alkaline cleaner and simultaneous thermal treatment of the dishes with steam, the molecular structures of Spülgutverschmutzungen (food residues, food residues, etc.) are solved, losing their adhesion to the dishes. After the above-mentioned pretreatment with highly concentrated alkaline cleaning solution and simultaneous thermal treatment with steam, the main cleaning step takes place, which can take place in a conventional manner. The main cleaning step may be assisted to assist the washing power by hot water vapor during which the main cleaning step is introduced into the treatment chamber.

Due to the even distribution of steam, steam has an advantage over a conventional washing cycle, especially in shadow zones of the dishes. Steam reaches each item of washware within the processing chamber in equal parts, regardless of the position and orientation of the items to be washed, such as the plates, cups, trays, pans and pots.

Further features of the invention are contained in the subclaims.

Fig. 1

schematisch eine Geschirrspülmaschine nach der Erfindung,

Fig. 2

schematisch eine weitere Ausführungsform einer Geschirrspülmaschine nach der Erfindung,

Fig. 3

schematisch eine weitere Ausführungsform einer Geschirrspülmaschine nach der Erfindung,

Fig. 4

schematisch eine weitere Ausführungsform einer Geschirrspülmaschine nach der Erfindung,

Fig. 5

schematisch eine weitere Ausführungsform einer Geschirrspülmaschine nach der Erfindung,

Fig. 6

schematisch eine weitere Ausführungsform einer Geschirrspülmaschine nach der Erfindung.

The invention will now be described by way of example with reference to the accompanying drawings of preferred embodiments of the invention. In the drawings show

Fig. 1

schematically a dishwasher according to the invention,

Fig. 2

schematically another embodiment of a dishwasher according to the invention,

Fig. 3

schematically another embodiment of a dishwasher according to the invention,

Fig. 4

schematically another embodiment of a dishwasher according to the invention,

Fig. 5

schematically another embodiment of a dishwasher according to the invention,

Fig. 6

schematically another embodiment of a dishwasher according to the invention.

The FIGS. 1 to 6 show six different embodiments of dishwashers 100, 200, 300, 400, 500, and 600 according to the invention.

The invention relates to dishwashers, in particular commercial dishwashers, which can also be labeled as utensil dishwashers (warewashers), in the form of a program automaton. They contain a program control device 2 for controlling at least one cleaning program and a treatment chamber 4 closable by a door (not shown) or a hood (not shown) in a machine housing 6 for receiving items to be cleaned (not shown) such as crockery, cutlery, Pots, pans and trays.

Under the treatment chamber 4 is a wash tank 8 for receiving sprayed liquid from the treatment chamber 4. A washing pump 10 is provided for conveying washing liquid from the wash tank 8 through a washing liquid conduit system 12 to washing nozzles 14 and 16, which in the treatment chamber 4 to the area of the items to be cleaned are directed and spray the washing liquid on the items to be cleaned. The sprayed washing liquid falls by gravity back into the wash tank 8. As a result, the wash tank 8, the washing pump 10, the washing liquid piping system 12, the washing nozzles 14 and 16 together with the cleaning chamber 4 form a washing liquid circuit. The washing liquid piping 12 connects the pressure side of the washing pump 10 with the washing nozzles 14 and 16.

Furthermore, a rinse aid 18 is provided for conveying rinse liquid by means of a rinse aid 20 through a rinse liquid line system 22 to rinse nozzles 24 and 26, which are directed in the treatment chamber 4 to the region of the ware to be cleaned. The sprayed rinse liquid falls by gravity from the treatment chamber 4 in the wash tank 8. Das Rinse liquid line system 22 connects the pressure side of the rinse pump 20 to the rinse nozzles 24 and 26.

The washing nozzles 14 and 16 and the rinse nozzles 24 and 26 can be arranged in the regions above and / or below and, if desired, also laterally of the washware region and in each case directed against the region in which the washware is positioned.

Preferably, a plurality of wash nozzles 14 are provided on at least one upper wash arm 15, a plurality of wash nozzles 16 on at least one lower wash arm 17, a plurality of rinse nozzles 24 on at least one upper rinse arm 25, and a plurality of rinse nozzles 26 on at least one lower rinse arm 27 ,

Before rinsing liquid is sprayed, in each case one of the rinse liquid corresponding amount of washing liquid is pumped out of the wash tank 8 by means of a drain pump 30 whose suction side is connected to a sump 32 of the wash tank 8.

If the wash tank 8 is empty before a first start of the dishwasher, it must first be filled with fresh water via a fresh water line (not shown) or with the rinse aid 18 and its rinse aid 20 with fresh water or with another final rinse liquid.

The final rinse liquid may be fresh water or fresh water mixed with rinse aid.

The washing liquid contains a detergent, which is automatically added to the liquid contained in the washing tank 8 by a detergent metering device (not shown).

All dishwashers of the invention include a steam device with a steam generator for generating and introducing water vapor into the steam generator Treatment chamber to apply it to the dishes with water vapor. The steam device can be realized in various embodiments. Examples are in the FIGS. 1 to 6 shown.

In the following, the differences of the various embodiments 100 to 600 are described in the FIGS. 1 to 6 are shown.

For the dishwashers 100, 200 and 300 of the FIGS. 1 . 2 and 3 is the suction side of the rinse pump 20 via a Rücksaugverhinderer 34 with a fresh water connection 36 connectable. The back suction preventer 34 (air gap) prevents a sucking back of liquid from the final rinse liquid line system 22 via the fresh water connection 36 into the public water supply network. Between the Rücksaugverhinderer 34 and the suction side of the rinse pump 20, a water heater 35 may be located.

The dishwashers 100, 200 and 300 of the FIGS. 1 . 2 and 3 are provided with a steam device 38 which includes a steam generator 40, the steam side 41 is connected via a steam line 42 to the treatment chamber 4 and the water side with a fresh water connection 36 is connected, for example via a check valve 37. The downstream end 44 of the steam line 42 ends For example, in a side wall of the treatment chamber. 4

The steam generator 40 may also be integrated into the dishwasher such that its steam outlet 41 opens directly into the treatment chamber 4, without the steam line 42. For example, the steam generator 40 can be arranged under the treatment chamber 4.

For the dishwashers 400, 500 and 600 of the FIGS. 4 . 5 and 6 a combined water heater and steam device 48 is provided instead of the steam device 38. The water heater and steam device 48 includes a steam generator 50. The steam generator 50 is connectable to a fresh water connection 36 and has a steam outlet 51, softer, Further, the steam generator 50 has a rinsing liquid outlet 55, which is connected to the suction side of the rinse aid 20 for conveying rinse liquid through the final rinse liquid line system 22 to the rinse nozzles 24 and 26.

The steam generator 50 includes a heater 56. Steam or heated final rinse liquid can be generated through it.

The program control device 2 of the dishwashers 100, 200, 300, 400, 500 and 600 of the FIGS. 1 to 6 contains at least one cleaning program, which is designed to carry out the program steps according to claim 1:

Spraying the dishes with the alkaline, highly concentrated detergent solution whose pH is at least 1 above the pH of the wash cycle of the main wash cycle can be accomplished in a variety of ways.

According to a preferred embodiment of the invention, a supply and spray system is provided, by means of which the alkaline, highly concentrated detergent solution whose pH is at least 1 above the pH of the washing liquid of a main wash cycle, conveyed out of a detergent solution container and in the Treatment chamber 4 can be sprayed on the dishes.

With the dishwashers 100 and 400 of the FIGS. 1 and 4 For example, a supply and spray system 110 for the alkaline, highly concentrated detergent solution is provided, which consists of a feed device 112 and a spray device 114. The feeder 112 includes a cleaner solution pump 60 having a suction side 61 and a pressure side 62. Connected to the suction side 61 is a suction line 64 for conveying alkaline concentrated cleaner solution 66 from a cleaner solution tank 68.

The spray device 114 consists of a connected to the pressure side 62 of the cleaner solution pump 60 cleanser solution line system 70 and attached cleaning solution nozzles, z. B. Cleaner solution nozzles 74, which are formed in a preferably above the Spülgutbereichs the cleaning chamber 4 arranged Reinigerlösungsarm 75, and / or cleaning solution nozzles 76 which are formed in a preferably below the Spülgutbereichs the cleaning chamber 4 arranged Reinigerlösungsarm 77.

The washing machines 200 and 400 of the Figures 2 and 4 again have the supply device 112 for the alkaline, highly concentrated detergent solution, but here no separate spray device 114 is provided, but the pressure side 62 of the detergent solution pump 60 is connected via a connecting line 78 to the final rinse liquid line system 22. As a result, rinse aid liquid or the alkaline, highly concentrated cleaner solution 66 can be sprayed onto the washware via the rinse nozzles 24, 26 as an alternative. The high-concentration cleaner supply and spray system 120 of these dishwashing machines 200 and 400 thus consists of the feed device 112 and the final-rinse liquid line system 22 as well as the rinse-aid nozzles 24 and 26.

For the dishwashers 300 and 600 of the Figures 3 and 6 For example, a supply and spray system 130 is provided for the alkaline, high-concentration cleaner solution which in turn contains the delivery device 112, but not the spray system 114. As the spray system, the scrubbing liquid spray system is used by connecting the pressure side 62 of the scrubber solution pump 60 to the scrubbing liquid line system 12 via a connection line 78. As a result, by means of the washing nozzles 14 and 16 alternatively washing liquid or the alkaline, highly concentrated cleaning solution 66 can be sprayed.

The program control device 2 controls the washing pump 10, the rinse pump 20, the drainage pump 30 and the detergent solution pump 60 as a function of the respective cleaning program selected by the operator on the program control device 2. At least one cleaning program is provided, preferably a plurality of optionally selectable cleaning programs are provided.

The at least one cleaning program according to the invention is designed such that the introduction of steam into the treatment chamber for the thermal pretreatment of the ware according to step 2, already started after the beginning, but before the end of step 1, preferably during the last quarter the duration of step 1.

Furthermore, the at least one cleaning program can be designed such that the spraying of the items to be washed with an alkaline, highly concentrated detergent solution according to step 1 is carried out for a period in the range between 5 seconds and 30 seconds, preferably between 10 seconds and 20 seconds.

According to a further embodiment of the invention, the cleaner program can be designed such that the thermal effect of steam on the items to be washed during said step 2 during a period in the range between 0.5 minutes to 7 minutes, preferably in a range between 1 minute to 4 minutes.

To shorten the cleaning period, it may also be advantageous that at least during a portion of the period during which the wash ware is sprayed with wash liquid according to step 3, also introduced steam into the cleaning chamber and the wash ware is acted upon with the water vapor.

It is particularly advantageous if according to the invention includes the cleaning program that is used as washing liquid for carrying out the main wash cycle according to step 3 washing liquid containing detergent, and a pH in the range between 9.0 and 11, preferably between 9.5 and 10.5 has.

Furthermore, it can advantageously be provided in the cleaning program that the pH of the alkaline, highly concentrated cleaning solution for spraying the dishes according to step 1 is at least 11.

Furthermore, the at least one cleaning program for cleaning items which is heavily soiled and / or contains stubborn dirt can include that before spraying the dishes with an alkaline, highly concentrated cleaning solution according to step 1, a pre-cleaning step is carried out, during which the Washware with liquid, preferably detergent containing washing liquid is sprayed.

Claims (8)

1. Method for operating a dishwasher, in particular a commercial dishwasher, which is in the form of a box-type dishwasher and has a treatment chamber for cleaning items to be washed, the method having the following successive steps:

   step 1: carrying out a pretreatment cycle,

   step 2: thermally treating the items to be washed with steam;

   step 3: carrying out a main wash cycle comprising spraying the items to be washed with wash liquid which contains water and detergent;

   step 4: carrying out a final rinse cycle during which the items to be washed are sprayed with final rinse liquid,

   characterized
   in that the pretreatment cycle comprises spraying the items to be washed with an alkaline, highly concentrated detergent solution whose pH is at least 1 higher than the pH of the wash liquid of a main wash cycle;
   in that the thermal treatment is carried out during an action cycle of the alkaline detergent solution during an action time period during which the detergent solution acts on the items to be washed, with the thermal pretreatment of the items to be washed being carried out over at least a portion of the action time period, preferably over the entire action time period;
   and in that the introduction of steam into the treatment chamber for the thermal pretreatment of the items to be washed according to step 2 is started as early as after the beginning but before the end of step 1, preferably during the last quarter of the duration of step 1.
2. Method according to the preceding claim,
   characterized
   in that the items to be washed are sprayed with an alkaline, highly concentrated detergent solution according to step 1 over a time period in the range of between 5 seconds and 30 seconds, preferably between 10 seconds and 20 seconds.
3. Method according to one of the preceding claims,
   characterized
   in that steam thermally acts on the items to be washed during step 2 over a time period in the range of between 0.5 minutes and 7 minutes, preferably in a range of between 1 minute and 4 minutes.
4. Method according to one of the preceding claims,
   characterized
   in that steam is also introduced into the cleaning chamber and the items to be washed are subjected to the action of the steam at least during a portion of the time period during which the items to be washed are sprayed with wash liquid according to step 3.
5. Method according to one of the preceding claims,
   characterized
   in that wash liquid which contains detergent and has a pH in a range of between 9.0 and 11, preferably between 9.5 and 10.5, is used as the wash liquid for carrying out the main wash cycle according to step 3.
6. Method according to one of the preceding claims,
   characterized
   in that the pH of the alkaline, highly concentrated detergent solution for spraying the dishes according to step 1 is at least 11.
7. Method according to one of the preceding claims,
   characterized
   in that at least one precleaning step during which the items to be washed are sprayed with liquid, preferably wash liquid containing detergent, is carried out before the dishes are sprayed with an alkaline, highly concentrated detergent solution according to step 1.
8. Dishwasher (100; 200; 300; 400; 500; 600), in particular commercial dishwasher, in the form of a box-type dishwasher, comprising a program-control device (2) for controlling at least one cleaning program, a treatment chamber (4) for accommodating items to be cleaned; a wash tank (8) for collecting sprayed liquid from the treatment chamber (4); a wash pump (10) for conveying wash liquid from the wash tank (8) to wash nozzles (14, 16) which, in the treatment chamber (4), are directed at the region of the items to be cleaned; a final rinse apparatus (18) for conveying final rinse liquid to final rinse nozzles (24, 26) which, in the treatment chamber (4), are directed at the region of the items to be cleaned; a steam apparatus (38; 48) having a steam generator (40; 50) for generating steam and introducing it into the treatment chamber (4) and therein onto the items to be cleaned;
   characterized
   in that a supply and spray system (110; 120; 130) is provided for supplying alkaline, highly concentrated detergent solution according to one of the preceding claims and for spraying this detergent solution onto items to be cleaned in the treatment chamber (4), and in that the program-control device (2) and the at least one cleaning program are designed to carry out the method according to one of the preceding claims during the at least one cleaning program.

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