EP1793724B1 - Dishwasher machine with thermal aftertreatment - Google Patents

Abstract

The invention relates to a method for operating a dishwasher machine (1), and to a corresponding dishwasher machine. Items to be washed (3) are washing with a washing product in the dishwasher machine (1) and then rinsed with fresh water (20) heated in a boiler (9). The items to be washed (3) are then subjected to a thermal aftertreatment with steam. The steam for the thermal aftertreatment is produced in the boiler (9) for heating the fresh water (20), and introduced into the dishwasher machine (1) by means of washing systems (12, 13) provided for the rinsing.

Description

The invention relates to a dishwasher with thermal treatment of the items to be washed, in particular after cleaning and rinsing the same. The dishwasher comprises a tank system in which, after cleaning the items to be washed with rinsing liquor and the rinse of the items to be washed with fresh water, a thermal treatment of the items to be cleaned with steam.

State of the art

In dishwashers, where the items to be washed are not transported during the cleaning process, two basic variants are distinguished.

On the one hand, dishwashers with a tank system are known in which a rinsing eye is kept in a tank. With this is, without being discarded after a cleaning cycle, repeatedly washed dishes cleaned. After the cleaning process, fresh water which has been heated in a boiler or a water heater is applied to the items to be washed by means of an additional rinse-aid system. This introduced rinse water is used in whole or in part to regenerate the rinse liquor. These machines are mainly used in commercial enterprises because short cycle times can be achieved. The cleaning of the dishes is carried out with the rinse liquor in a chemo-thermal process step, while the rinse is usually done with heated fresh water.

On the other hand, dishwashers with a water change system are known. For machines operated according to this principle, fresh water is used for the cleaning and rinsing process step in each cleaning cycle, or the rinse water from the first cleaning cycle is used as the cleaning liquor for the second Used cleaning cycle and then discarded. These machines are mainly used in the household sector.

Due to the respective exchange of the rinsing liquor longer cycle times are given compared to dishwashers with tank system. Due to the respective replacement of the cleaning solution and the rinsing solution, different temperatures can be run in the cleaning programs in each cycle. The cleaning of the items to be cleaned takes place in a chemo-thermal process step. By longer heating phases can also be carried out thermal processes.

Out DE 299 23 594 U1 is a dishwasher known. This dishwasher comprises at least one rinsing chamber and in each case one rinsing water tank associated with each rinsing chamber. Optionally, a heating device for the rinse water in the rinse water tank is provided as well as a circulation pump for the rinse water with motor drive. This aspirates via a suction heated rinse water from the rinse water tank and this leads via at least one pressure line spray nozzles to at least one spray device to spray rinse water on the items to be washed. This is accommodated on a holder inside the rinsing chamber. An air supply device is provided, which is integrated in the intake line of the circulating pump. Furthermore, a control device is provided, which makes it possible to allow only in the initial phase of the rinsing process with hot water, an air supply.

WO 2004/058035 A1 also refers to a dishwasher. This has a rinsing container, in which the items to be washed is received and a means for circulating liquid, and means for heating the liquid. Furthermore, a spraying device for applying the liquid to the items to be washed is provided when a washing operation is selected by a control device. Furthermore, the dishwasher comprises a device for providing steam, which has a separate steam chamber with integrated heating. This is connected to the bottom of the washing container, wherein with the steam chamber and the bottom of the washing container, a steam nozzle is coupled, through which the pressure of the steam for flowing into the washing can be adjusted.

Out DE 29 00 954 A1 a dishwashing machine for receiving dishes arranged in a washing container is known, which comprises a pump for circulating Liquid, a water heater for heating liquid and a spray device for applying the liquid to the items to be washed in case of failure of a flushing operation by a control device. In addition, this dishwasher has a device for providing steam upon activation of a separate, running between pre-wash cycle and main rinse steam rinse cycle. This means for providing the steam is arranged directly below the spray directly in the washing container and essentially comprises a heater with a downwardly open cover with a raised portion, are formed in the steam discharge openings. When steam rinsing the water - heated after the inlet into the washing up to a predetermined water level level - of the heater, so that water vapor is formed. This can escape via the steam discharge openings in each case in the washing at any point uncontrolled. The steam purging used according to this solution for solving heavily soiled items and is initiated by the user via the controller in case of failure of a corresponding program.

document GB-A-2 192 532 discloses a method of operating a dishwasher according to the preamble of claim 1 and a dishwasher according to the preamble of claim 8.

Presentation of the invention

With the proposed method for operating a dishwasher according to the invention, a cleaning of the items to be washed by rinsing liquor from a tank, wherein the rinse liquor is sprayed onto the items to be cleaned with a pump via a rinsing system with nozzles. Subsequently, a rinse with heated fresh water, which is previously heated in a boiler and is applied by means of another pump via a provided in the dishwasher rinse aid with nozzles on the dishes. A thermal aftertreatment of the items to be cleaned with steam follows this, wherein the steam is generated in the boiler, which is present for heating the fresh water required for the rinse in the dishwasher. The steam generated in the boiler is applied to the rinse aid provided in a chamber of the dishwasher via the rinse aid provided for the final rinse.

The inventively proposed method for operating a dishwasher, a separate steam generating unit for generating the steam required for the thermal aftertreatment can be avoided. Rather, can to Steam generation of anyway used in the dishwasher for heating the fresh water boiler are used.

To generate the steam required for the thermal aftertreatment of the items to be cleaned, the level of the fresh water stored in the boiler is always maintained via a controller associated with the dishwasher so that heating of the fresh water flowing in or of the fresh water contained in the boiler is always covered by fresh water.

The control contained in the dishwasher switches on the rinsing the pumping water pump and after the completion of the rinsing process again off before a heated fresh water promotional pump is turned on. Between the switch-off of the flushing eye the circulating pump and the switch-on of the heated fresh water promotional further pump may be a drip break, during which the rinse liquor and washed particles can drain into the lying below the chamber for receiving the wash ware tank. After the final rinse step, an optional dripping pause takes place, during which the further pump delivering the heated fresh water remains switched off. The controller of the dishwasher now initiates switching on of the heating provided in the boiler, which produces steam in the boiler, which is introduced via a steam line into the rinse aid of the dishwasher and thus enters the chamber of the dishwasher, in which the rinsed dishes are included.

Optionally, cooling or drying of the items to be washed by introducing air or cold water into the chamber of the dishwasher can take place after the thermal after-treatment step of the cleaned and rinsed items.

According to the invention, a dishwashing machine is also proposed which has a chamber receiving the items to be cleaned and a pump containing a washing-up nozzle. The dishwasher further comprises a fresh water pumping further pump and a boiler in which the fresh water is heated by means of a heater. The boiler includes a steam line, which is connected to supply line for spray systems for rinsing the items to be rinsed. By means of this solution, the steam generated in the boiler after the rinsing step is introduced into the spraying systems which have previously been exposed to heated fresh water and via which to these Spray systems formed nozzles in the clear rinse dishes receiving chamber of the dishwasher introduced.

In order to build up a sufficient vapor pressure level, a valve is accommodated in the steam line, the outlet point of which is arranged in the upper region of the boiler. The valve can be formed, for example, as a spring-loaded check valve. About this a back pressure in the steam line is removed and on reaching a certain pressure level, the steam flows into the intended for rinsing spray systems. The suction for the heated fresh water from the boiler promotional further pump is arranged so that it is always below the fresh water level of the boiler and the heated fresh water promotional pump sucks no steam.

drawing

With reference to the drawing, the invention will be described below in more detail.

The sole FIGURE shows a dishwashing machine proposed according to the invention in a schematic representation.

variants

The illustration of the figure is a dishwasher 1 can be seen. In this a fixed via suitable brackets within the dishwasher basket 2 for receiving the items to be cleaned 3 is provided. The dishwasher 1 shown schematically can be designed both as a front-loaded unit or as a push-through unit. The dishwasher 1 comprises a tank 4 for receiving the rinsing eye. Within the tank 4, a heater 5 is arranged to heat the rinse liquor. The rinsing liquor contained in the tank 4 is mixed with cleaner and brought to temperature via the heater 5.

The heated rinse liquor is introduced via a circulating pump 6 into a rinsing system 7 for rinsing liquor and exits via rinsing system 7 formed nozzles 8 for rinsing. About the nozzles 8, the rinse liquor is sprayed onto the dishes 3 and thus the Washware cleaned. The rinse liquor falls from the ware 3 in the tank 4 and is circulated by means of the circulating pump 6 on.

Furthermore, the dishwasher 1 comprises a boiler 9. In the boiler 9 there is a heater 10 in order to heat the fresh water 20 contained in the boiler 9. The filling of the boiler 9 via a filling valve 15. The boiler 9 and the chamber of the dishwasher 1 are connected via a vent line 14 in conjunction with each other.

The boiler 9 is associated with a further pump 11, via which the heated by means of the heater 10 fresh water rinsing systems 12 for the rinsing of the ware 3 is supplied after the rinsing step. The rinsing systems 12 for the rinsing are designed as spraying systems, so that the heated fresh water can be finely distributed to nozzles 13 in which the clearing dishwashing dishes 3 receiving chamber of the dishwasher 1 can be initiated.

In the boiler 9 remains at the rinse in any case so much fresh water 20 that the fresh water 20 heating heating is always covered by water.

After the rinsing process, the heater 10 is turned on, so that steam 9 forms in the boiler, which is passed through the steam line 16 and the recorded therein check valve 17 in the rinsing system 12 for rinsing. The steam flows via the nozzles 13 into the dishwasher 3 receiving chamber of the dishwasher and impinges on the dishes 3. Depending on the selected program for the dishwasher 1, the heater 10 and thus the steam generation is set and completed the thermal aftertreatment.

Before removal of the cleaned, rinsed and thermally post-treated items 3 from the dishwasher 1, cooling or drying of the items 3 by blowing air or cold water can optionally take place.

The dishwasher 1 comprises a controller 22 via the controller 22, the program is started so that the pump 6 promotes circulation of the soapy water through the flushing system 7 to the nozzle 8. About the nozzles 8, the rinse liquor is sprayed onto the items 3 to be cleaned and thus cleaned the items to be washed. The rinsing eye then falls from the items to be washed 3 in the tank 4 and is further circulated there.

After cleaning, the circulating pump 6 is switched off via the controller 22. After a draining pause, while the impurities and rinsing liquor from the items 3 to be cleaned drips, the heated fresh water promotional further pump 11 is turned on and the heated fresh water (rinse water) through the rinsing system 12 for rinse, which is designed as a spray system, and provided on this Nozzles 13 sprayed onto the cleaned items 3, so that this is rinsed clear. As a result, adhering dirt particles and the rinse liquor are washed off. The rinse water drops into the tank 4 and serves to regenerate the rinsing liquor stored in this tank. Any excess flushing liquor is pumped off or runs into a process not shown here.

The supply of fresh water contained in the boiler 9 is so dimensioned that in any case the heating provided in the boiler 9 remains covered, indicated in the figure by the cover level 21 for fresh water 20.

About the controller 22, the heater 10 is turned on after completion of the rinse step. Steam is thereby formed in the boiler 10, which is introduced into the flushing system 12 for rinsing via the steam line 16 and the valve 17 provided therein, which may be designed as a non-return valve, for example. The steam is fed into the compartment of the dishwasher 1 accommodating the items to be washed 3, that is to say via a component already present in the dishwasher 1, namely the rinsing system 12 for the final rinse. The rinsing system 12 for the rinse is preferably designed with nozzles 13 as a spray system.

Depending on the selected program, the heater 10 of the boiler 9 and thus the steam generation is set, whereby the thermal treatment of the cleaned, rinsed clean items 3 is completed. Before the items to be washed 3 are removed from the dishwasher 1, a cooling or drying of the items 3 by blowing air or by introducing cold water into the dishwasher 1 can take place. Thereafter, a re-filling of the boiler 9 with fresh water by controlling the filling valve 15 via the controller 12. The controller 22 also initiates the heating of the fresh water in the boiler 9 by switching on the heater 10th

After removal of the cleaned, rinsed and thermally aftertreated items to be washed and optionally after cooling, new items 3 can be introduced for a new cleaning cycle and the next rinsing operation can be started via the controller 22.

The steam line 16, which is connected in the upper part of the boiler 9, connects this with the supply line for heated fresh water for a flushing system 12 for rinsing the dishes 3. For pressure buildup in the steam line 16 a valve 17 is provided in this, which, for example as Check valve can be formed. Depending on the applied closing force a corresponding pressure is built up in front of the check valve 17. After exceeding the closing force of the valve 17, the steam flows via the steam line 16 and the rinsing systems 12 for rinsing with nozzles 13 in the chamber of the dishwasher 1 a. During steam generation, it is ensured that the level of the fresh water 20 in the boiler 9 does not fall below a cover level 21 at which the heater 10 of the boiler 9 is covered with fresh water 20. A refilling of the boiler 9 with cold fresh water takes place by activating a filling valve 15 via the controller 22 of the dishwasher 1. The suction point, to which the heated fresh water promotional further pump 11 is connected, is indicated by reference numeral 19. Due to the position of the suction point 19 for the further pump 11 on the boiler 9 it is ensured that the further heated fresh water pump 11 draws in exclusively water. By means of the position of the discharge point 18 in the upper region of the boiler 9, it is ensured that only water vapor flows into the steam line 16, which can then be introduced into the chamber of the dishwasher 1 via the rinsing system 12 for the final rinse.

By inventively proposed solution can be advantageously avoided to provide a separate steam generating unit for steam generation. By means of the machine control 22, the boiler 9 and its heating 10 can be used both for heating the fresh water 20 stored in the boiler 9 and for generating steam after the final rinse in the dishwasher 1. The control 22 also ensures that the fresh water level of fresh water 20 within the boiler 9 not below the level of coverage 21, in which the heater 10 is still covered by fresh water 20 drops. For this purpose, the controller 22 also controls the opening and closing of the filling valve 15, via which cold fresh water flows into the boiler 9.

In the boiler 9 nachströmenden cold fresh water, the temperature of the stored in the boiler 9, already heated fresh water 20 decreases, whereby the heater 10 of the boiler 9 is turned on again via the controller 22. The heated supply of fresh water in the boiler 9 is maintained in this way to the temperature required for the final rinse. During steam generation of the steam required for the thermal aftertreatment in the boiler 9, it is ensured via the controller 22 that the cover level 21 of the fresh water 20 does not fall below the coverage level 21 of the heater 10.

LIST OF REFERENCE NUMBERS

1

dishwasher

2

basket

3

ware

4

Tank for rinsing eye

5

Heating for rinse liquor

6

circulating pump

7

Rinsing system for rinsing eye

8th

Nozzles for soapy water

9

boiler

10

Heating for rinse water and thermal aftertreatment

11

additional pump (for rinsing)

12

Rinsing system for rinsing

13

Nozzles for rinsing

14

vent line

15

filling valve

16

steam line

17

Valve (check valve)

18

Mouth point steam line

19

Intake point further pump 11

20

fresh water

21

Covering level heating 10

22

control

Claims (13)

1. Method for operating a dishwasher (1) in which wash ware (3) is cleaned using wash liquor and is then subjected to final rinsing with fresh water (20) which is heated in a boiler (9), characterized in that the wash ware (3) is subjected to thermal aftertreatment with steam, with the steam for the thermal aftertreatment being generated in the boiler (9) for heating the fresh water (20), and being introduced into the dishwasher (1) via a steam line (16), which allows backpressure to build up, by dishwashing systems (12, 13) which are provided for final rinsing.
2. Method according to Claim 1, characterized in that the level of fresh water (20) stored in the boiler (9) is always kept above a level (21) for covering a heater (10) of the boiler (9).
3. Method according to Claim 1, characterized in that enough fresh water (20) to always keep a heater (10) covered by fresh water (20) remains in the boiler (9) after each final-rinse process.
4. Method according to Claim 1, characterized in that a controller (22) switches on a pump (6) which circulates the wash liquor, and switches off the said pump after the dishwashing process, and switches off a further pump (11) which delivers heated fresh water (20).
5. Method according to Claim 4, characterized in that a draining interval is provided between switch-off of the pump (6) which circulates wash liquor and switch-on of the further pump (11) which delivers heated fresh water (20).
6. Method according to Claim 1, characterized in that a heater (10) which is associated with the boiler (9) is switched on after final rinsing of the wash ware (3), and steam flows into a chamber of the dishwasher (1), which chamber accommodates the wash ware (3), via a steam line (16) with a valve (17).
7. Method according to Claim 1, characterized in that, after the thermal-aftertreatment step for the wash ware (3), the wash ware (3) is cooled or dried by introducing air or cold water.
8. Dishwasher (1) for carrying out the method according to the preceding claims, having a chamber which accommodates wash ware (3), a pump (6) which circulates wash liquor, and a boiler (9) in which the fresh water (20) is heated, characterized in that the fresh water (20) is delivered by a further pump (11), and in that the boiler (9) has a steam line (16) which is connected to supply lines for dishwashing systems (12, 13) for final rinsing of the wash ware (3).
9. Dishwasher (1) according to Claim 8, characterized in that the steam line (16) contains a valve (17) which builds up a backpressure.
10. Dishwasher (1) according to Claim 9, characterized in that the valve (17) is designed as a non-return valve.
11. Dishwasher (1) according to Claim 8, characterized in that the steam line (16) is connected in the upper region of the boiler (9).
12. Dishwasher (1) according to Claim 11, characterized in that an issuing point (18) of the steam line (16) is situated above a covering level (21) for a heater (10) in the boiler (9).
13. Dishwasher (1) according to Claim 8, characterized in that an intake point (19) for the further pump (11) for delivering the heated fresh water (20) is situated below a covering level (21) for a heater (10) which is accommodated in the boiler (9).

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