DE102010029887A1 - Dishwasher, has rinsing container for receiving dishes, and applicator device for providing rinsing water for washing dishes, and catalyzer for ozone decomposition, where catalyzer is arranged on surface portion of exhaust duct - Google Patents

Abstract

The dishwasher (100) has a rinsing container (140) that is provided for receiving dishes, and an applicator device (295) for providing rinsing water for washing dishes, and a catalyzer (260) for ozone decomposition. An exhaust air drying system includes an exhaust duct (240) and an exhaust blower (220). The catalyzer is arranged on a surface portion of the exhaust duct and/or a surface portion of the exhaust blower. The catalyzer is provided with catalytic active nanoparticles. An independent claim is also included for a method for operating a dishwasher.

Description

The invention relates to a dishwasher with a rinsing container, which is provided for receiving items to be washed and at least one device, with which rinsing solution can be applied to the items to be washed. Furthermore, the invention relates to a method for operating such a dishwasher.

From the WO 2005/063109 A1 It is known to equip a dishwasher with an ozone generator and to add the ozone generated therewith to the washing container or the rinsing water. In this way, the oxidizing effect of the ozone for cleaning and / or disinfecting the dishes in the dishwasher can be used.

The disadvantage, however, is that ozone generates a pungent smell in the perception of a user when it accidentally exits when opening the door or leaks from the washing. In addition to the unpleasant perception of ozone may cause the user if necessary eye irritation, skin irritation and irritation of the mucous membranes.

The invention is therefore based on the object to prevent the release of ozone into the environment by a dishwasher equipped with an ozone generator.

The object is achieved by a dishwasher with a washing container, which is provided for receiving items to be washed and at least one device with which wash liquor can be applied to the items to be washed, wherein the dishwasher contains at least one catalyst for ozone decomposition.

The dishwashing machine proposed according to the invention preferably comprises a control and / or regulating device which controls the components of the dishwasher in such a way that at least one washing program with partial program steps is realized.

Furthermore, the solution of the object in a method for operating a dishwasher with a washing compartment, which is provided for receiving items to be washed, which includes sub-program steps, wherein in at least one partial program step rinse liquor is applied to the items to be washed and in at least one partial program step of the rinsing liquor or rinsing liquor and / or the raw water and / or into the interior of the washing container for use for at least one partial program step ozone is added, wherein in at least one partial program step, the air volume present in the washing is at least partially brought into contact with at least one catalyst to the present in the air volume ozone at least partially decomposing.

According to the invention, it is also proposed to provide at least one catalyst in the dishwasher in addition to the ozone generator. Such a catalyst lowers the activation energy for at least one ozone-decomposing chemical reaction so far that the thermal energy in the dishwasher is sufficient to decompose the ozone. For example, the ozone on the surface of the catalyst can be converted to molecular oxygen.

In one embodiment of the invention, the dishwasher may be provided with an exhaust air drying system comprising at least one exhaust duct and an exhaust fan. This exhaust air drying system can remove the resulting in the dish drying moist air, for example, from the washing and z. B. derive through a wall opening in the room of the dishwasher to the outside. However, it may in particular be formed together with the washing compartment as a self-contained air circulation system. This may be for air drying preferably one with a heat transfer medium such. B. water-filled heat exchanger or reservoir, which is in heat-conducting contact with at least one wall of the washing, so that condenses due to a temperature difference between the temperature of the air and the temperature of the cooled by means of this reservoir wall of the washing humidity and the air is dried , The reservoir is preferably filled with a heat transfer medium, in particular water, which has a filling temperature or an initial starting temperature lower than the air to be dried. It may therefore be provided to dry the air sucked out of the washing container via a condensation heat exchanger and to feed it back into the washing container. Regardless of which of these variants is selected, the catalyst can be arranged at least on a partial surface of the exhaust air duct and / or a partial surface of the exhaust fan. Preferably, but not necessarily, the entire surface of the exhaust duct can be coated with the catalyst. In this way, the extracted air volume from the washing container is brought into contact with the catalyst only during the drying process of the dishes, wherein the ozone contained in the air volume is reliably destroyed. In particular, it may be expedient if no catalytically active material is provided in the washing itself, so that the ozone is not decomposed prematurely before the dishes are cleaned and / or disinfected.

Alternatively or cumulatively, the catalyst may also be formed as a honeycomb catalyst, which is introduced into an exhaust air duct. Such a honeycomb catalyst has a porous base body, for example of a metal foam, an extruded plastic or ceramic. This porous base body preferably has a cross section which corresponds to the cross section of the exhaust air duct. In this way it is ensured that the entire volume of air flowing through the exhaust air duct is passed through the base body. Catalytically active material is applied to the surfaces of the pores and / or channels passing through the porous base body, for example in the form of nanoparticles having a diameter of approximately 1 nm to 1 μm. Such a honeycomb catalyst may have a larger surface area than the boundary surface of a tube receiving the honeycomb catalyst.

In a further expedient embodiment of the invention, the catalyst proposed according to the invention can be arranged at least on a partial surface of the inner wall of the washing container. In this case, those surface areas are preferably selected on which the air volume preferably passes along by thermal movement. In this way, during a partial program step, in particular during dish drying, the air volume is brought into contact, at least to a large extent, with the catalyst, the resulting ozone decomposing.

In an advantageous development of the invention, it can be provided that the dishwasher has a device which prevents the opening of a door of the washing container during predefinable partial program steps and / or as a function of at least one measuring signal of at least one ozone sensor. In particular, during such partial program steps, which include the addition of ozone in the wash liquor or in the washing, the release of this ozone can be reliably prevented by locking the door. If an ozone sensor is provided in the washing container, the door lock can be activated event-controlled, d. H. The door is only released when the assigned sensor reports an ozone concentration below a predefinable limit.

Even in the case of a dishwashing machine equipped with a catalytic converter according to the invention, in some embodiments the ozone may not be completely decomposed. Thus, in some embodiments of the invention, it may already be considered sufficient to degrade the ozone to a predeterminable limit below which nuisance and / or health hazard to the user is no longer present.

Other developments of the invention are given in the dependent claims.

The invention and its developments are explained in more detail with reference to drawings.

Each show schematically:

1 the basic structure of a dishwasher,

2 a cross section through a dishwasher according to a first advantageous embodiment of the invention,

3 a cross section through a dishwasher according to a second advantageous embodiment of the invention, and

4 an advantageous embodiment of the catalyst used.

Elements with the same function and mode of action are in the 1 With 4 each provided with the same reference numerals.

1 shows a dishwasher 100 with a rinse tank 140 , The washing container 140 is from a sink wall 115 bounded and forward with a door 120 provided, through which the washing container 140 with dishes 145 can be loaded. The washing-up wall 115 For example, it is made of stainless steel. In the interior of the washing container 140 the dishwasher is the dishes 145 in a conventional manner in baskets 130 arranged. Continue to be in the washing 140 stationary or on rotating spray arms arranged spray nozzles, which during the rinsing a rinsing liquor or rinsing liquor liquid, in particular water with or without detergents, additives, rinse aid, and / or food residues, on the inside of the rinse 140 located dishes 145 to distribute.

After the last partial rinse of a selected dishwasher program that is in the washing 140 located dishes 145 dried in a further part program step. This is the dishes 145 heated to an elevated temperature to evaporate the adhering moisture. In the interior of the washing container 140 thus forms moist air. To cool down a new condensation of moisture on the dishes 145 To prevent, the inside of the washing container 140 air is dehumidified, or from the washing 140 dissipated. In particular, a drying device may be provided for this purpose, which forms a closed air circulation system together with the washing container.

2 shows a cross section through a dishwasher 100 according to a first embodiment of the invention. The dishwasher has a washing container 140 on which of a container wall 115 is limited. The washing container 140 is by means of a door 120 accessible to be equipped with crockery. A crockery basket is an example 130 shown. Furthermore, the dishwasher contains 100 an ozone generator 290 with which ozone can be generated for use in at least one partial program step. The ozone can then be added to the raw water and / or the rinsing liquor liquid and / or into the interior of the rinsing container. Furthermore, the dishwasher contains 100 a known device 295 , with which wash liquor on the items to be washed 145 can be applied. For clarity, in 2 not essential to the invention components not shown.

These include, for example, other baskets, circulating pumps, lye pumps, program sequence control and other modules.

In the embodiment according to 2 becomes during the dish drying in the last partial program steps accumulating damp air for drying over the outlet opening 245 from the washing container 140 in the exhaust duct 240 aspirated. To generate this air movement, a mechanical ventilation device is available. This contains a fan 230 , which has a rotating shaft with an electric motor 220 connected is. The sucked air is through the exhaust air duct 240 to a condensation heat exchanger 210 passed, condensed on the cooling surfaces contained in the intake air moisture contained. The condensed moisture can be fed in a conventional manner a sewer or a collection container or recycled into the washing. The cooled and dried air in this way is via the second exhaust duct 250 and the inlet opening 255 in the washing container 140 where it is again available for drying the dishes. The through the two air duct sections 240 . 250 formed air circulation channel thus forms together with the washing a closed air circulation.

During the drying step, the washing can 140 Ozone are added, which simultaneously with the drying of a disinfection of the dishes in the dishwasher 100 causes. In some cases, the ozone may also have been added to the rinsing liquor and / or the raw water in a preceding partial program step, so that a residual concentration of ozone in the rinsing tank remains during the drying step 140 located. This is a device 290 for generating ozone, by means of which ozone can be generated in one or more partial program steps.

To prevent the ozone from escaping from the washing container 140 to prevent during the program, is at the door 120 a door locking device 280 to disposal. The door locking device can either be controlled by the program sequence control such that it during predeterminable part program steps the door 120 locks, in particular those partial program steps in which an ozone addition takes place. In a further development of the invention can also in the washing 140 an ozone sensor may be present which, when a predetermined concentration is exceeded, the door lock 280 activated.

In order to reduce the ozone concentration at the end of the program below a predefinable limit, are in the exhaust duct 240 and / or in the exhaust duct 250 catalytically active coatings 260 and / or honeycomb catalysts 270 brought in. A catalytically active coating 260 In this case, for example, comprises a catalyst material, which by means of a carrier material on the inner wall of the exhaust air duct 240 and / or the exhaust duct 250 is applied. The catalytically active coating can be either as a partial coating or as a full-surface coating of the inner wall of the exhaust duct 240 be executed.

To the catalytically effective contact surface for the exhaust air from the washing 140 To increase, in an embodiment of the invention, the impeller 230 the mechanical ventilation device with a catalytic coating 260 be provided.

If a honeycomb catalyst 270 is provided, this comprises a porous body, for example of a plastic material, a ceramic or a metal foam. The porous base body has openings, for example, channels, which a gas passage in the exhaust duct 250 allow guided exhaust air. Preferably, but not necessarily, has the main body of the honeycomb catalyst 270 a cross section, which is approximately the cross section of the exhaust duct 250 equivalent. In this way, the main body of the honeycomb catalyst 270 sealing in the exhaust duct 250 be introduced.

On the inside of the main body of the honeycomb catalyst 270 formed cavities or channels, a catalyst material is applied, which catalyzes the decomposition of the ozone. Due to the large number of openings and pores in the base body, the honeycomb catalyst 270 an enlarged surface on, leaving a larger amount of catalytic effective material can be introduced.

3 shows a cross section through a dishwasher 100 according to a further embodiment of the invention. Also the dishwasher 100 according to 3 has a rinse tank 140 on which of a Spülbehälterwand 115 is limited. Also the washing container 140 according to 3 is through a door 120 accessible. A crockery basket is an example 130 shown. Furthermore, the dishwasher contains 100 an ozone generator 290 with which ozone can be generated for use in at least one partial program step. The ozone can then be added to the raw water and / or the rinsing liquor and / or into the interior of the rinsing container. Furthermore, the dishwasher contains 100 a known device 295 , with which wash liquor on the items to be washed 145 can be applied. For clarity, in 2 not essential to the invention components not shown. These include, for example, other baskets, circulating pumps, lye pumps, program sequence control and other modules.

For dehumidifying the moist air in the interior of the rinsing tank during the drying process 140 is a condensation heat exchanger 210 intended. The condensation heat exchanger 210 has a heat transfer surface 200 on. The heat transfer surface 200 is a part of the Spülbehälterwand 115 , In the condensation heat exchanger 210 there is a heat transfer medium. For example, ambient air from the surrounding space or preferably cooling water, preferably supplied fresh water, can be used as the heat transfer medium. The heat transfer medium in the condensation heat exchanger 210 causes a cooling of the heat transfer surface 200 below the condensation temperature, so that in the rinse tank 140 moisture present at the heat transfer surface 200 condensed. The condensing moisture then runs to the lowest point of the washing container 140 where it can be removed by means of a sewage pump.

For decomposition of the in the washing container 140 located ozone is a catalyst 260 intended. This is a catalytically active coating of Spülbehälterinnenwand 115 executed. The catalyst 260 is preferred as a partial coating of Spülbehälterinnenwand 115 In this case, those partial surfaces are preferably selected, on which the in the washing 140 located air preferably swept along because of the air flow in the container. In the illustrated embodiment, it is assumed that the air rises due to its elevated temperature and therefore preferably the upper boundary surface or top wall of the washing 140 sweeps. In other embodiments of the invention, however, other air flows can be adjusted, so that a different partial surface of the Spülbehälterinnenwand 115 is selected for coating.

4 shows an exemplary embodiment of a catalytically active coating 260 , Exemplary shows 4 a section of a Spülbehälterinnenwand 115 , Of course, in the same way, the coating 260 also on the inner wall of an exhaust duct 240 or on the inner wall of an exhaust duct 250 be applied.

The catalytic effective coating 260 has a carrier material 410 into which catalytically active nanoparticles 420 are at least partially embedded. The partial embedding serves in particular to provide a catalytically active surface which is not of the carrier material 410 is covered.

The carrier material 410 in one embodiment of the invention comprises a polymer, for example epoxy, polyurethane or polyester resin. In this way, the carrier material 410 in a simple manner by rolling, spraying, knife coating or brushing on the surface of the Spülbehälterinnenwand 115 be applied.

In further embodiments of the invention, the carrier material 410 also have an open-pore foam structure made of metal or a mesh structure made of plastic. In this way, the catalytically active surface can be further increased. A metal foam preferably contains tin and / or zinc and / or aluminum and / or copper or an alloy which contains at least one of the metals mentioned. Particularly preferably, the metal foam can consist directly of the catalytically active material, for this purpose, preferably alloys are used which contain silver and / or nickel and / or copper and / or manganese.

If the carrier material 410 is made of plastic, it can be foamed and cured in a conventional manner. For example, such a foam structure may consist of polyurethane. Furthermore, such a plastic structure may consist of a reticulated, geometry-determining foam whose webs are coated on all sides and uniformly with a further plastic.

Finally, the open-pored foam structure becomes in particular by gluing, welding, soldering or clips on the Spülbehälterinnenwand 115 applied.

On the carrier material 410 are nanoparticles 420 which provide the catalytically active surface. The nanoparticles 420 in this case preferably have a diameter of about 1 nm to about 1 .mu.m, in particular about 10 nm to about 100 nm. The nanoparticles 420 In one embodiment, they may contain a metal or a metal oxide or an alloy or a corresponding oxide. In particular, the nanoparticles contain 420 Manganese and / or nickel and / or copper and / or cobalt and / or chromium and / or molybdenum and / or tungsten and / or titanium and / or zirconium and / or vanadium and / or niobium and / or aluminum and / or iron. In order to produce particles from an oxide, particles of a metal or an alloy can be produced in a first method step, which are subjected to an oxidizing thermal treatment in a second method step.

The inventively proposed catalyst 260 can thus easily in the dishwasher 100 be used. In particular, it is possible by the catalytically active coating shown, individual models or individual production series with the catalytically active coating 260 equip and other models or other production series without the catalytically active coating 260 to manufacture without making any constructive changes to the dishwasher 100 requirement.

The invention thus relates in summary to the decomposition of ozone to oxygen in dishwashers or to an ozone converter.

The emerging use of ozone to kill germs or improve cleaning performance in dishwashers also requires consideration of the environmental impact of ozone, particularly on humans. Ozone is subject to very narrow concentration limits in many industrialized countries and, in some countries, has a negative image. Therefore, appropriate safeguards are important when using this gas.

According to the invention, it was recognized that ozone can be decomposed very easily by catalysts to oxygen. In dishwashers with an exhaust air drying system in particular the coating of the exhaust duct and / or the exhaust fan is proposed with such (highly active) catalyst coatings, so that despite an induced ozone concentration in the rinsing the intentionally initiated for drying or accidentally occurring exhaust air (leakage during operation, eg. B. by the known "steam") is kept safe ozone free. A simple time or sensor-controlled opening lock of the flushing door ensures a maximum concentration of ozone to achieve a sufficient hygienic effect according to applicable regulations.

In circulating air drying / condensation systems such exhaust fans do not exist. For. this design variant is the o. g. Coating proposed for an internal recirculation system.

If such an internal air circulation system does not exist either, the application of the above mentioned g. Catalyst on the inner surface of the washing compartment expediently, preferably at those points where the air preferably passes along through the thermals.

As (highly active) catalysts are preferably nanobased systems in question, which provide their effect at temperatures well below 100 ° C and thus can be used in the work of dishwashers. They are easy to apply on all materials.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2005/063109 A1 [0002]

Claims (11)

Dishwasher ( 100 ) with a rinsing container ( 140 ), which for receiving dishes ( 145 ) and at least one device ( 295 ), with which rinse liquor on the items to be washed ( 145 ), characterized in that the dishwasher ( 100 ) further at least one catalyst ( 260 . 270 . 420 ) for ozone decomposition. Dishwasher according to claim 1, characterized in that it further comprises an exhaust air drying system, which at least one exhaust duct ( 240 . 250 ) and an exhaust fan ( 220 . 230 ), wherein the catalyst ( 260 ) at least on a partial surface of the exhaust duct ( 240 ) and / or a partial surface of the exhaust fan ( 230 ) is arranged. Dishwasher according to claim 2, characterized in that the catalyst ( 270 ) is formed as a honeycomb catalyst, which in the exhaust duct ( 250 ) is introduced. Dishwasher according to claim 1 or 3, characterized in that the catalyst ( 260 ) at least on a partial surface of the inner wall ( 115 ) of the washing container ( 140 ) is arranged. Dishwasher according to one of claims 1 to 4, characterized in that it comprises a device ( 280 ), which is the opening of a door ( 120 ) of the washing container ( 140 ) during predetermined subprogram steps and / or as a function of at least one measurement signal prevents at least one ozone sensor. Dishwasher according to one of claims 1 to 5, characterized in that the catalyst ( 420 ) has catalytically active nanoparticles. Dishwasher according to claim 6, characterized in that the nanoparticles ( 420 ) on a carrier material ( 410 ) are applied. Method for operating a dishwasher ( 100 ) with a rinsing container ( 140 ), which for receiving dishes ( 145 ), which comprises subprogram steps, wherein in at least one subprogram step rinsing liquor is applied to the ware ( 145 ) is applied and in at least one partial program step of the rinsing liquor and / or the raw water and / or in the interior of the washing ( 140 ) for use for at least one partial program step ozone is added, characterized in that in at least one partial program step, the volume of air present in the washing container at least partially with at least one catalyst ( 260 . 270 ) is brought into contact, wherein the ozone present in the air volume is at least partially decomposed. A method according to claim 8, characterized in that the volume of air by thermal movement of the catalyst ( 260 . 420 ) to be led. A method according to claim 8 or 9, characterized in that the volume of air through a fan to the catalyst ( 260 . 270 ) to be led. Method according to one of claims 8 to 10, characterized in that a door ( 120 ) of the washing container ( 140 ) is locked during predetermined subprogram steps and / or as a function of at least one measurement signal of at least one ozone sensor.

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