Dishwasher comprising a hydraulic arrangement for cleaning a filter device

Abstract

A dishwasher includes a dishwashing container accommodating items to be washed. A first hydraulic arrangement is provided to wash the items by a dishwashing fluid and includes a spray device arranged in the dishwashing container, a sump arranged below the dishwashing container, a filter device configured to filter the dishwashing fluid in the dishwashing container and/or the sump, and a circulating pump configured to circulate the dishwashing fluid to the spray device. A second hydraulic arrangement is provided for cleaning the filter device by a cleaning fluid. The second hydraulic arrangement includes the filter device, the sump, a pump arrangement, a storage device for holding the cleaning fluid, a cleaning device for spraying at least one segment of the filter device with the cleaning fluid, and an auxiliary pump arranged between the storage device and the cleaning device for applying pressure to the cleaning fluid.

Claims

1. A dishwasher, comprising: a dishwashing container accommodating items to be washed; a first hydraulic arrangement for washing the items by a dishwashing fluid, said first hydraulic arrangement comprising a spray device arranged in the dishwashing container, a sump arranged below the dishwashing container, a filter device configured to filter the dishwashing fluid in the dishwashing container and/or the sump, and a circulating pump configured to circulate the dishwashing fluid to the spray device; a second hydraulic arrangement for cleaning the filter device by a cleaning fluid, said second hydraulic arrangement comprising the filter device, the sump, a pump arrangement comprising at least the circulating pump, a storage device for holding the cleaning fluid, a cleaning device for spraying at least one segment of the filter device with the cleaning fluid, and an auxiliary pump arranged between the storage device and the cleaning device for applying pressure to the cleaning fluid; and a water switch arranged between the circulating pump, the spray device and the storage device, said water switch including an inlet connected to an outlet of the circulating pump, a first outlet connected to an inlet of the spray device, and a second outlet connected to a dishwashing fluid inlet of the storage device to circulate the dishwashing fluid to the storage device, such that the dishwashing fluid forms at least some of the cleaning fluid, wherein the storage device includes a separate fresh water inlet connection for filling the storage device with fresh water, such that the fresh water forms at least some of the cleaning fluid, with the separate fresh water inlet connection being independent from the dishwashing fluid inlet which is controlled by the water switch, wherein the storage device includes a chemical inlet and an automatic dosing apparatus for adding a chemical to the cleaning fluid in the storage device through the chemical inlet, the chemical being one or more agents that enhance a cleaning effect of the cleaning fluid with respect to the filter device, and wherein the circulating pump is configured to also circulate the cleaning fluid to the storage device via the water switch.

2. The dishwasher of claim 1, constructed in the form of a household dishwasher.

3. The dishwasher of claim 1, wherein the pump arrangement of the second hydraulic arrangement comprises a drain pump for conveying the cleaning fluid into a sewage line.

4. The dishwasher of claim 1, wherein the filter device comprises a number of filters.

5. The dishwasher of claim 4, wherein one filter of the number of filters of the filter device is configured as a cylindrical filter.

6. The dishwasher of claim 1, wherein the auxiliary pump is defined by a volumetric flow which is smaller than a volumetric flow of the pump arrangement.

7. The dishwasher of claim 1, wherein the auxiliary pump is configured to apply an additional pressure between 0.5 bar and 20 bar to the cleaning fluid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiment of the dishwasher are set out in the subclaims and the exemplary embodiments of the dishwasher described in the following. The dishwasher is also described in more detail based on preferred embodiments with reference to the accompanying figures.

(2) FIG. 1 shows a schematic perspective view of an exemplary embodiment of a dishwasher;

(3) FIG. 2 shows a schematic cross-sectional view of an exemplary embodiment of a dishwashing container of the dishwasher according to FIG. 1;

(4) FIG. 3 shows an schematic functional view of a first exemplary embodiment of hydraulic arrangements of the dishwasher;

(5) FIG. 4 shows a schematic functional view of a second exemplary embodiment of hydraulic arrangements of the dishwasher;

(6) FIG. 5 shows a schematic view of an exemplary embodiment of a storage device; and

(7) FIG. 6 shows a flow diagram of an exemplary embodiment of a method for operating a dishwasher.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

(8) Identical elements or those of identical function are shown with the same reference characters in the figures, unless otherwise specified.

(9) FIG. 1 shows a schematic perspective view of an exemplary embodiment of a dishwasher 1. The dishwasher 1 is a household dishwasher. The dishwasher 1 has a carcass, which comprises a dishwashing container 2, as well as a door 3. The dishwashing container 2 and door 3 form a dishwashing chamber 4 for washing items to be washed. The door 3 is shown in its opened position in FIG. 1. The door 3 can be closed or opened by pivoting about a pivot axis S provided at a lower end of the door 3. The dishwashing container 2 is box-shaped for example and can comprise a base 5, a top 6 positioned opposite the base 5, a rear wall 7 positioned opposite the door 3 and two opposing side walls 8, 9. The side walls 8, 9 in particular can be made of stainless steel. The dishwasher 1 also has at least one dish holder 10. A number of dish holders 10 in particular can be provided, comprising a lower rack, an upper rack and/or a flatware drawer. The several dish holders 10 are preferably arranged one above the other in the dishwashing container 2. Each dish holder 10 can be moved as required into an initial position in the dishwashing container 2 in an insertion direction 12 or out of it to an end position in a pull-out direction 13. A rail 11 is provided on both sides of a respective dish holder 10 for this purpose in the example in FIG. 1. The dishwasher 1 can be for example a freestanding, integrated or fully integrated dishwasher 1.

(10) FIG. 2 shows a schematic cross-sectional view of a dishwashing container 2 of a dishwasher 1 according to FIG. 1. Items to be washed (not shown) can be arranged in the dish holders 10 in the dishwashing container 4. Respective spray arms 14a, 14b are arranged below the respective dish holders 10, forming a spray device 14 for spraying the items to be washed in the dish holders 10 with dishwashing fluid. A sump 15 is provided with a downstream circulating pump 18 in the region of the base 5 of the dishwashing container 2, being connected to the spray device 14 for flow purposes by way of fluid lines (not shown). The sump 15 here is connected for flow purposes for example to a discharge line, in which a drain pump 19 is arranged to pump soiled dishwashing fluid out of the sump 15.

(11) As shown in FIG. 2, the upper face of the sump 15 is covered by a flat, funnel-shaped filter element 16a. A cylindrical filter 16b is positioned in the filter element 16a. The filter element 16a and the cylindrical filter 16b form a filter device 16. The cylindrical filter 16b serves as a segment of the filter device 16, which filters out dirt particles, which could block the circulating pump 18 and/or the drain pump 19. For further details relating to sump 15 and filter device 16, see WO 2009/077286 A1, the entire contents of which are deemed to be contained herein.

(12) The filtered dirt particles can block the cylindrical filter 16b and adversely affect the dishwashing performance of the dishwasher, for which reason automatic cleaning of the cylindrical filter 16b is provided in the dishwasher 1. To this end a cleaning device 17 for spraying the sleeve of the cylindrical filter 16b with cleaning fluid is arranged in proximity to the cylindrical filter 16b. In FIG. 2 the cleaning device 17 is configured around the outer lateral surface of the cylindrical filter 16b. Alternatively the cleaning device 17 can also be arranged in the interior of the cylindrical filter 16b. The cleaning device 17 is connected to an upstream auxiliary pump 20 for flow purposes, said auxiliary pump 20 applying pressure to the cleaning fluid and conveying it to the cleaning device 17.

(13) FIG. 3 shows a schematic functional view of a first exemplary embodiment of hydraulic arrangements 31, 32 of the dishwasher 1.

(14) In particular FIG. 3 shows hydraulic devices 14, 15, 16, 17, 18, 19, 20, 21, 22, which form a first hydraulic arrangement 31 and a second hydraulic arrangement 32.

(15) The first hydraulic arrangement 31 is a hydraulic circuit arrangement and comprises the spray device 14, the filter device 16, the sump 15, the circulating pump 18 and a water switch 21. The filter device 16 in particular comprises a cylindrical filter 16b. The above-mentioned hydraulic devices 14, 16, 15, 18, 21 of the first hydraulic arrangement 31 here are connected to one another to form a circuit for flow purposes by way of fluid lines shown as broken arrows. The first hydraulic arrangement 31 is designed to wash the items to be washed that are accommodated in the dishwashing container 2 from FIGS. 1, 2 in a wash mode. In wash mode dishwashing fluid is conveyed by the circulating pump 19 from the sump 15 by way of the water switch 21 to the spray device 14 in the dishwashing container 2, spraying the items to be washed accommodated in the dishwashing container 2 with the dishwashing fluid. The dishwashing fluid mixes with dirt particles adhering to the items to be washed and the dishwashing fluid mixed with dirt particles drops from the items to be washed onto the base 5 of the dishwashing container 2 and drains through the filter device 16, in particular the cylindrical filter 16b, into the sump 15. The cylindrical filter 16b filters dirt particles out of the dishwashing fluid in the process. In wash mode a column of fluid formed from dishwashing fluid is present in the sump 15 and/or cylindrical filter 16b. The dishwashing fluid is circulated out of the sump 15 back toward the water switch 21 and spray device 14.

(16) It should be noted that the first hydraulic arrangement 31 can also be provided with a dishwashing fluid connection (not shown), by way of which the dishwashing fluid is supplied to the first hydraulic arrangement 31 in the wash mode described above at the start of operation of the dishwasher 1. The dishwashing fluid is for example fresh water, to which chemicals are added. The dishwashing fluid can be taken from a dishwashing liquor storage unit for example, as shown in FIG. 5 and described further below.

(17) The second hydraulic arrangement 32 is a hydraulic circuit arrangement and comprises the filter device 16, in particular the cylindrical filter 16b, as well as the sump 15, the circulating pump 18, the water switch 21, a storage device 22, the auxiliary pump 20 and the cleaning device 17. The above-mentioned hydraulic devices 16, 15, 17, 18, 20, 21 22 of the second hydraulic arrangement 32 here are connected to one another for flow purposes by way of fluid lines shown as continuous arrows. Where a broken and continuous arrow run parallel, it can be the same fluid line, which is used by both the first hydraulic arrangement 31 and the second hydraulic arrangement 32. The second hydraulic arrangement 32 is designed to clean the cylindrical filter 16b by means of cleaning fluid in a cleaning mode. In cleaning mode the cleaning fluid is conveyed by the auxiliary pump 20 from the storage device 22 to the cleaning device 17 and in the in the process subjected to a pressure of for example between 0.5 and 20 bar. Such a high pressure would be for example damaging to items to be washed accommodated in the dishwashing container 2, for which reason the circulating pump 18, which is also contained in the first hydraulic arrangement 31, is not designed to generate such a high pressure. Such a high pressure is however not damaging for the filter device 16. The dimensions of the auxiliary pump 20 are therefore not subject to the same restrictions as those of the circulating pump 18. The cleaning fluid, to which pressure is applied, sprays out of the cleaning device 17 onto the surface of the cylindrical filter 16b, cleaning it as a result. The cleaning fluid then passes into the sump 15 and is circulated from there by way of the water switch 21 into the storage device 22 by the circulating pump 18.

(18) The auxiliary pump 20 in particular generates a smaller volumetric flow than the circulating pump 18. This means that all the cleaning fluid reaching the sump 15 is pumped out of the sump 15 immediately and there is no column of fluid in the cylindrical filter 16b in cleaning mode. If the cleaning device 17 is arranged inside the cylindrical filter 16b, the cleaning fluid can therefore strike the inner lateral surface of the cylindrical filter 16b without being slowed down. If the cleaning device 17 is arranged outside the cylindrical filter 16b, dirt particles released from the cleaning fluid striking the outer lateral surface of the cylindrical filter 16b are not impeded by a column of fluid in the cylindrical filter 16b as they exit the cylindrical filter 16b.

(19) In the present exemplary embodiment the storage device 22 is a dishwashing liquor storage unit and the cleaning fluid is formed from the dishwashing fluid.

(20) According to the present exemplary embodiment the cleaning fluid is subjected to a high pressure by the auxiliary pump 20. As the auxiliary pump 20 generates a smaller volumetric flow than the circulating pump 18, there is essentially no column of fluid in the cylindrical filter 16b. This brings about effective cleaning of the cylindrical filter 16b of the filter device 16. Water consumption is low, as circulating dishwashing fluid is used as the cleaning fluid.

(21) FIG. 4 shows a schematic functional view of a second exemplary embodiment of hydraulic arrangements 31, 32 of the dishwasher 1. FIG. 5 shows a schematic view of an exemplary embodiment of a storage device 22. The second exemplary embodiment is described in more detail in the following with reference to FIG. 4 and FIG. 5. Elements of identical function in the second exemplary embodiment have the same reference characters as the corresponding elements in the first exemplary embodiment and are not described again.

(22) The second exemplary embodiment shown in FIG. 4 differs from the first exemplary embodiment in that the second hydraulic arrangement 32 is not closed to form a circuit. According to the second exemplary embodiment the sump 15 is connected to the drain pump 19, which conveys cleaning fluid from the sump 15 into sewage, in other words to a sewage line, and in the process generates a larger volumetric flow than the auxiliary pump 20. There is therefore no column of fluid in the cylindrical filter 16b and/or in the sump 15 in cleaning mode in the second exemplary embodiment either.

(23) The storage device 22 shown in FIG. 5 is a dishwashing liquor storage unit, which is provided with an inlet 23, an outlet 24, a fresh water connection 25 and an automatic dosing apparatus 26. The inlet 23 is connected for flow purposes to the water switch 21 from FIG. 4. The outlet 24 is connected for flow purposes to the auxiliary pump 20 of the second hydraulic arrangement 32 from FIG. 4. The outlet 24 can also be connected by way of a water switch (not shown) to a dishwashing fluid connection (not shown) of the first hydraulic arrangement 31. The fresh water connection 25 is connected for flow purposes to a pressure valve (not shown) and is designed to fill the storage device 22 with fresh water. The automatic dosing apparatus 26 is designed to add chemicals to the fluid in the storage device 22 to improve its dishwashing and/or cleaning effect.

(24) Use of the storage device 22 allows the cleaning fluid for use in the second hydraulic arrangement 32 to be formed partially from dishwashing fluid circulated from the first hydraulic arrangement 31 by way of the water switch 21 and partially from fresh water to which chemicals have been added. In other words in wash mode or after wash mode before the start of cleaning mode dishwashing fluid, which has been circulated in the first hydraulic arrangement 31 in wash mode, can be conveyed by way of the water switch 21 into the storage device 22 of the second hydraulic arrangement. In cleaning mode used cleaning fluid is conveyed from the sump 15 into sewage by the drain pump 19 and the cleaning fluid that is thus removed is replaced by supplying fresh water to the storage device 22 by way of the fresh water connection 25 and adding chemicals to the cleaning fluid in the storage device 22 by way of the dosing apparatus 26.

(25) According to the second exemplary embodiment the cleaning effect of the cleaning fluid can be improved, as soiled cleaning fluid is not circulated after cleaning and at least some of the cleaning fluid is formed from fresh water. The other advantages of the second exemplary embodiment are the same as the advantages of the first exemplary embodiment.

(26) FIG. 6 shows a flow diagram of an exemplary embodiment of a method for operating a dishwasher 1, in particular a household dishwasher, as described for example with reference to FIGS. 1 to 5.

(27) The method comprises a step 601 for washing items to be washed accommodated in a dishwashing container 2 by circulating a dishwashing fluid in a first hydraulic arrangement 31 by means of a circulating pump 18 and a step 602 for cleaning a filter device 16 by means of cleaning fluid in a second hydraulic arrangement 32. The hydraulic arrangements 31, 32 of the method correspond in particular to the hydraulic arrangements 31, 32 of the dishwasher 1 in FIGS. 1 to 5.

(28) The step 602 in particular comprises pumping the cleaning fluid out of the storage device 22 to the cleaning device 17 while the auxiliary pump 20 applies pressure thereto, spraying at least one segment of the filter device 16 with the cleaning fluid by means of the cleaning device 17 and pumping the cleaning fluid out of the sump 16 by means of the pump arrangement, which can comprise the circulating pump 18 and/or the drain pump 19 according to exemplary embodiments.

(29) Although the present invention has been described with reference to exemplary embodiments, it can be modified in many different ways. For example some of the cleaning fluid can be circulated in an alternating manner or simultaneously and some can be conveyed into sewage. In particular if the cleaning fluid is not formed from the dishwashing liquor, the storage device 22 can be any other hollow space with a capacity of preferably at least 2 l, for example a capacitor container of a heat pump-type dishwasher or a water pocket.