Water-using domestic appliance and method for operating a water-using domestic appliance

A water-using household appliance includes a pump sump, a filter element arranged at least partially in the pump sump, and a nozzle unit arranged on the pump sump. The nozzle unit produces an annular flow between the pump sump and the filter element in order to remove dirt from the filter element, with the annular flow flowing around the filter element only in one direction of flow.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is the U.S. National Stage of International Application No. PCT/EP2018/076070, filed Sep. 26, 2018, which designated the United States and has been published as International Publication No. WO 2019/068528 A1 and which claims the priority of German Patent Application, Serial No. 10 2017 217 801.9, filed Oct. 6, 2017, pursuant to 35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The present invention relates to a water-using household appliance and a method for operating a water-using household appliance.

A dishwasher has a dishwasher cavity, on the base of which a pump sump can be provided. A filter sieve for filtering washing liquor is normally arranged in the pump sump. This can be removed and manually cleaned in order to clean the filter sieve.

U.S. Pat. No. 7,431,774 B2 further shows a dishwasher with a pump sump and a filter arranged in the pump sump. Cleaning nozzles are provided in the pump sump and have a plurality of fluid outlet openings for spraying the filter.

BRIEF SUMMARY OF THE INVENTION

Against this background an object of the present invention consists in providing an improved water-using household appliance.

Accordingly a water-using household appliance, in particular a household dishwasher, is provided with a pump sump, a filter element arranged at least partially in the pump sump, and a nozzle unit which is arranged on the pump sump, wherein the nozzle unit is designed to produce an annular flow between the pump sump and the filter element in order to remove dirt from the filter element, said flow flowing around the filter element only in one direction of flow.

It has surprisingly been found that with the help of the annular flow a homogeneous cleaning effect can be achieved on the filter element, in particular over 360°. The filter element is preferably accommodated by a filter receptacle of the filter element. A “direction of flow” here means a clockwise flow or an anti-clockwise flow. The direction of flow preferably runs along a substantially circular or oval path. The nozzle unit is preferably arranged at least partially between the pump sump and the filter element. “Annular flow” means a fluid mass flow, in particular a washing liquor mass flow. “Washing liquor” here means a fluid such as water for example, which for example can contain cleaning additives and sometimes dirt. The nozzle unit is preferably a separate component from the pump sump, which for example comprises plastic or metal or is formed from plastic or metal. The nozzle unit can alternatively be integrally molded from a single piece of material on the pump sump. The nozzle unit preferably comprises a channel for channeling a fluid or washing liquor.

According to one embodiment the filter element comprises a microfilter which is embodied as tubular, a microfilter inner side enclosing an inner compartment of the microfilter and a microfilter outer side, wherein the nozzle unit is designed to produce the annular flow around the microfilter outer side, such that the dirt is removed from the microfilter inner side toward the inner compartment.

The advantage of this is that the microfilter inner side, which can have an increased tendency to soil, can be cleaned and the corresponding dirt sucked directly out of the inner compartment. Furthermore, the filter element can comprise a coarse filter which is arranged above the microfilter and is for example connected thereto. Furthermore, the filter element can comprise a fine filter, which is for example arranged above the microfilter and sometimes around the coarse filter. The fine filter can for example be embodied as a flat and fine sieve structure. The coarse filter can for example be pot-shaped and can be embodied as a coarse sieve structure. The microfilter can also be embodied as a sieve structure. Furthermore, another tubular sieve structure different from the sieve structure can be embodied radially outside and/or radially inside the sieve structure of the microfilter. The microfilter can thus for example be formed from different sieve structures. The microfilter inner side and/or the microfilter outer side can for example substantially have the shape of a cylindrical jacket. The microfilter inner side and/or the microfilter outer side can for example have the shape of an endless bellows. “Tubular” here means that the microfilter is embodied as annular, in particular circular, in cross-section. The nozzle unit preferably merely comprises fluid outlet openings or one fluid outlet opening, each of which is designed to form or ensure a fluid outlet running substantially tangentially to a tubular shape of the microfilter.

According to a further embodiment the water-using household appliance comprises a drain pump which is designed to suck washing liquor together with dirt directly out of the inner compartment.

The advantage of this is that the dirt can be sucked directly out of the inner compartment, in which the dirt exhibits the greatest blockage effect. The pump sump for example comprises an opening which faces the inner compartment of the microfilter and by means of which the drain pump sucks washing liquor out of the inner compartment of the microfilter. The drain pump is for example designed to suck or convey washing liquor together with dirt to a drain outside the household appliance.

According to a further embodiment the pump sump has a side wall which surrounds the filter element, so that an annular gap is formed between the filter element and the side wall.

For example, the side wall is a wall of the filter receptacle of the pump sump. A base wall can for example be integrally molded onto the side wall, and together these form the filter receptacle. The side wall and the filter element are arranged such that the annular flow is formed or created. In this case the annular flow runs along the wall. The side wall surrounds the filter element for example radially and extends in a depth direction which for example points perpendicularly downward. For example, the side wall has a radial opening, through which washing liquor filtered by the filter element and flowing from the inner compartment of the microfilter to the annular gap can be conveyed. The annular gap can be seen as an annular space between the microfilter and the filter receptacle.

According to a further embodiment the nozzle unit comprises a first nozzle section which projects from above into the annular gap.

The advantage of this is that an initial region of the annular flow can be oriented precisely and in particular tangentially to the tubular shape of the microfilter. The first nozzle section preferably comprises one or more fluid outlet openings, each of which is designed to form or ensure the fluid outlet running substantially tangentially to the tubular shape of the microfilter.

According to a further embodiment the nozzle unit comprises a second nozzle section, on which the first nozzle section is integrally molded and which extends away from the annular gap.

The second nozzle section extends for example radially or tangentially away from the annular shape of the microfilter. The advantage of this is that flow losses can be reduced, since a channel of the second nozzle section has fewer curves or none at all.

According to a further embodiment the first nozzle section is curved around the filter element.

The advantage of this is that the first nozzle section fits perfectly into the annular gap, since the first nozzle section for example follows the course of the annular gap in one section of the annular gap. The first nozzle section for example has the shape of a segment of a circle.

According to a further embodiment the water-using household appliance comprises a water switch which is designed to interrupt a supply of fluid to the nozzle unit, so that the annular flow is interrupted.

The advantage of this is that the nozzle unit or the annular flow can be selectively actuated and hence does not have to run permanently during a wash cycle of the household appliance.

According to a further embodiment the water-using household appliance comprises one spray arm and/or two spray arms and/or a ceiling spray device, wherein the water switch is designed to interrupt and/or control a supply of fluid to the spray arm and/or the two spray arms and/or the ceiling spray device.

For example, the pump sump comprises a circulation pump which is designed to circulate washing liquor and to supply the first spray arm and/or the second spray arm and/or the ceiling spray device with washing liquor. Corresponding channels are of course embodied.

Furthermore, a method for operating a water-using household appliance, in particular as described above, is provided, wherein with the help of a nozzle unit an annular flow is produced between a pump sump and the filter element in order to remove dirt from the filter element, said flow flowing around a filter element only in one direction of flow.

According to a further embodiment, the annular flow is produced for between 20 and 240 seconds, preferably for between 40 and 220 seconds and further preferably for between 60 and 180 seconds.

According to a further embodiment a first wash cycle is performed, in which washing liquor is circulated within the water-using household appliance, wherein after the first wash cycle a first suction removal of washing liquor together with dirt is performed with the help of a drain pump, and wherein the annular flow is produced during, in particular at the end of, the first wash cycle.

For example, the annular flow is interrupted before the first suction removal of washing liquor. “Suction removal” can in this instance also be referred to as pumping out.

According to a further embodiment a second wash cycle, in which washing liquor is circulated within the water-using household appliance, is performed after the first suction removal, wherein after the second wash cycle a second suction removal of washing liquor together with dirt is performed with the help of the drain pump, and wherein the annular flow is produced during, in particular at the end of, the second wash cycle.

For example, the annular flow is interrupted before the second suction removal of washing liquor.

According to a further embodiment the annular flow is produced during a suction removal of washing liquor together with dirt with the help of a drain pump.

According to a further embodiment the annular flow is actuated by switching a water switch.

The embodiments, features and advantages described for the proposed device apply correspondingly to the proposed method and vice versa.

Further possible implementations of the invention also comprise combinations—not explicitly cited—of features or embodiments described above or below in respect of the exemplary embodiments. In this context, the person skilled in the art will also add individual aspects as improvements or enhancements to the respective basic form of the invention.

In the figures, elements that are identical or have the same function are provided with the same reference characters unless otherwise stated.

FIG.1shows a schematic perspective view of a water-using household appliance1, in particular a household dishwasher. The household appliance1comprises a dishwasher cavity2, which can be closed by a door3, in particular in a watertight manner. To this end, a sealing facility can be provided between the door3and the dishwasher cavity2. The dishwasher cavity2is preferably cuboid in shape. The dishwasher cavity2can be arranged in a housing of the household appliance1. The dishwasher cavity2and the door3can form a dishwasher interior4for washing items to be washed.

The door3is shown in its opened position inFIG.1. The door3can be closed or opened by pivoting about a pivot axis5provided on a lower end of the door3. A loading opening6of the dishwasher cavity2can be closed or opened with the aid of the door3. The dishwasher cavity2has a base plate7, a ceiling8arranged opposite the base plate7, a rear wall9arranged opposite the closed door3and two side walls10,11arranged opposite one another. The base plate7, the ceiling8, the rear wall9and the side walls10,11can be manufactured from a sheet steel, for instance. In particular, the base plate7can be manufactured from a different material to that of the ceiling8and the side walls10,11, for instance. For instance, the base plate7can be manufactured from the material1.4301, the ceiling8and the side walls10,11from the material1.4016and the rear wall9likewise from the material1.4016. It is furthermore possible for the base plate7to be made from a plastic material.

The household appliance1further has a base arrangement12provided on the base plate7. The household appliance1furthermore has at least one receptacle for items to be washed13to15. A number of, for instance three, receptacles for items to be washed13to15can preferably be provided, wherein the receptacle for items to be washed13can be a lower receptacle for items to be washed or a bottom basket, the receptacle for items to be washed14can be an upper receptacle for items to be washed or an upper basket and the receptacle for items to be washed15can be a cutlery drawer. As also shown inFIG.1, the receptacles for items to be washed13to15are arranged one above the other in the dishwasher cavity2. Each receptacle for items to be washed13to15can optionally be moved in or out of the dishwasher cavity2. Each receptacle for items to be washed13to15can be inserted into the dishwasher cavity2in an insertion direction E and extracted from the dishwasher cavity2in an extraction direction A opposite to the insertion direction E.

Furthermore, a ceiling spray device16is provided on the ceiling6, and is designed to spray washing liquor in the dishwasher interior4. A spray arm38(in this case also referred to as the first spray arm) is further provided between the base plate7and the receptacle for items to be washed13. The spray arm38is rotatably connected to the base plate7and/or the base arrangement12and is designed to spray washing liquor in the dishwasher interior4. In addition, a spray arm39(in this case also referred to as the second spray arm) is provided, and is rotatably connected to an underside of the receptacle for items to be washed14and is designed to spray washing liquor in the dishwasher interior4.

FIG.2shows a first embodiment of the base arrangement12of the household appliance1seen from a schematic top view. The base arrangement12comprises a pump sump17, a filter element18at least partially arranged in the pump sump17, and a nozzle unit19which is arranged at least partially between the pump sump17and the filter element18, wherein the nozzle unit19is designed to produce an annular flow20between a side wall21of the pump sump17and the filter element18in order to remove dirt from the filter element18, said flow flowing only in one direction of flow R around the filter element18.

The pump sump17can be embodied as integral, in particular made from a single piece of material, with the dishwasher cavity2, in particular with the base plate7. In this case the side wall21extends in a depth direction z, which points from the ceiling8(seeFIG.1) perpendicularly downward to the base plate7(seeFIG.1). The direction of flow R furthermore runs perpendicular to the depth direction z and for example anti-clockwise in the top view. Alternatively the direction of flow R can run clockwise seen in the top view. Integrally molded onto the side wall21is a base wall22which preferably runs substantially perpendicular to the side wall21and on which the filter element18stands. The side wall21and the base wall22form a filter receptacle for the pump sump17.

The filter element18comprises a microfilter23which is embodied as tubular, a microfilter inner side25enclosing an inner compartment24of the microfilter23, and has a microfilter outer side26, wherein the nozzle unit19is designed to produce the annular flow20around the microfilter outer side26, so that the dirt is removed from the microfilter inner side25to the inner compartment24. The base arrangement12further comprises a drain pump27, which is designed to suck washing liquor together with dirt directly out of the inner compartment24. An opening28of the pump sump17arranged underneath the inner compartment24is provided for this, and faces the inner compartment24and is fluidically connected to the drain pump27with the help of a fluid channel (not shown) arranged underneath the opening28.

The side wall21surrounds the filter element18such that an annular gap29is formed between the filter element18and the side wall21. The side wall21in this case has, seen from the top view, an angular shape, wherein the side wall21has rounded and flattened wall sections. Alternatively, the side wall21could, seen in the top view, have no corners and for example have a circular or oval contour.

The nozzle unit19comprises a first nozzle section30which projects from above into the annular gap29and has a fluid outlet opening32, from which a jet of fluid leaves the nozzle unit19to form the annular flow20. The nozzle unit19additionally has a second nozzle section31, on which the first nozzle section30is integrally molded, wherein the second nozzle section31extends away from the annular gap29. Preferably only fluid outlet openings32are provided on the nozzle unit19, each of which is designed to form or to ensure a fluid outlet running substantially tangentially to the annular shape of the microfilter23. In other words, for example, no fluid outlet opening is provided on the nozzle unit19, which forms a fluid outlet direct to the inner compartment24.

The base arrangement12further comprises a water switch33, which is designed to interrupt a supply of fluid to the nozzle unit19, so that the annular flow20is interrupted. The water switch33is further designed to interrupt and/or control a supply of fluid to the spray arm38(seeFIG.1) and/or the spray arm39(seeFIG.1) and/or the ceiling spray device16(seeFIG.1). The pump sump17further comprises a first opening34, with the help of which the ceiling spray device16is supplied with washing liquor, and/or a second opening35, with the help of which the spray arm39is supplied with washing liquor, and/or a third opening36, with the help of which the spray arm38is supplied with washing liquor.

FIG.3shows a second embodiment of the base arrangement12of the household device1seen from a schematic top view. In contrast toFIG.2, the first nozzle section30is curved around the filter element18. In this case a wall37of the first nozzle section30faces the filter element18and is adapted to the tubular shape of the microfilter23. The advantage of this is that the first nozzle section30fits perfectly into the annular gap29, since the first nozzle section30follows at least partially the course of the annular gap29.

For example, the first nozzle section30extends out of the annular gap29counter to the depth direction z and merges into the second nozzle section31, which extends to the water switch33. In this case the second nozzle section31extends substantially perpendicular to the depth direction z.

FIG.4shows a schematic diagram of an exemplary spray process40for the water-using household appliance1according toFIG.1. In this case an amount of washing liquor M, which is circulated in a washing circuit of the household appliance1by means of a circulation pump (not shown) of the pump sump17, is plotted over a time t, during which the washing process40runs.

The washing process40starts at a time point t0. The amount of washing liquor M is increased by means of a supply of fresh water between the time point t0and a time point t1. A pre-wash cycle41is started between the time points t1and t2. The drain pump27is activated between the time point t2and a time point t3and as a result the amount of washing liquor M decreases. The amount of washing liquor M is then increased until a time point t4and a wash cycle42(also referred to here as the first wash cycle) is started, which is performed until the time point t6. Washing liquor circulates within the water-using household appliance1during the wash cycle42. The circulating (or circulation) is carried out with the help of the circulation pump. The drain pump27is activated between the time point t6and t7and washing liquor is for example substantially completely or partially pumped out. This can be referred to as suction removal45(also referred to here as the first suction removal).

Fresh water is supplied to the household appliance1between the time point t7and a time point t8and as a result the amount of washing liquor M is increased, wherein a further wash cycle43(also referred to here as the second wash cycle) is started at the time point t8and is performed until a time point t10. The drain pump27is activated between the time point t10and a time point t11and washing liquor is for example substantially completely or partially pumped out. This can be referred to as suction removal46(also referred to here as the second suction removal), wherein washing liquor together with dirt is sucked out with the help of the drain pump27. Fresh water is supplied to the household appliance1between the time point t11and a time point t12and as a result the amount of washing liquor M is again increased, wherein a rinse cycle44is started at the time point t12and is performed until a time point t14. The drain pump27is activated between the time point t14and a time point t15and washing liquor is substantially completely pumped out. This can be referred to as suction removal47(for example the third suction removal). The washing process40is terminated at the time point t15, for example. Drying cycles can of course follow on from the washing process40.

The annular flow20is preferably produced during, in particular at the end of, the wash cycle42between a time point t5and the time point t6and/or the time point t7. After the suction removal45the wash cycle43, in which washing liquor is circulated within the water-using household appliance1, is performed, wherein after the wash cycle43the suction removal46of washing liquor together with dirt is performed with the help of the drain pump27, and wherein the annular flow20is produced during, in particular at the end of, the second wash cycle43between a time point t9and the time point t10and/or t11. Furthermore, the annular flow20is for example produced during, in particular at the end of, the rinse cycle44between a time point t13and the time point t14and/or t15. Washing liquor pumped off during the suction removal47preferably has a higher temperature than washing liquor pumped off during the suction removal45or the suction removal46. The temperature of washing liquor can be 55° C. to 65° C., in particular 58° C. or 63° C., before or during the suction removal47. Because of the higher temperature an increased cleaning effect can be achieved on the filter element18. Furthermore, the annular flow20between the time point t13and the time point t14or the time point t15can be activated for longer than the annular flow20between the time point t5and the time point t6or the time point t7and/or than the annular flow20between the time point t9and the time point t10or the time point t11.

The annular flow20can for example be produced for between 20 and 240 seconds, preferably for between 40 and 220 seconds and further preferably for between 60 and 180 seconds. For example the annular flow20is produced for 90 seconds between the time points t5and t6or t7. For example the annular flow20is produced for 90 seconds between the time points t9and t10or t11. For example the annular flow20is produced for 180 seconds between the time points t3and t14or t15. For example the annular flow20is produced during a suction removal45,46,47of washing liquor together with dirt with the help of the drain pump27. The annular flow20can for example also be activated exactly once, twice, three times, four times or five times during the washing process40, e.g. during the pre-wash cycle41and/or during the wash cycle42and/or during the wash cycle43and/or during the rinse cycle44and/or during the suction removal45and/or during the suction removal46and/or during the suction removal47.

For example the annular flow20is in each case actuated with the help of a switching of the water switch33. The amount of washing liquor M remains substantially constant during the pre-wash cycle41, the first wash cycle42, the second wash cycle43and the rinse cycle44. The time points t0to t15are of course numbered in chronological order. The wash cycle42can be referred to as the cleaning phase and the wash cycle43as the intermediate washing phase. For example, the drain pump27and the nozzle unit19can be activated simultaneously in order to bring about an increased removal effect on the dirt.

Although the present invention has been described with reference to exemplary embodiments, it can be modified in numerous different ways.