Means for preventing the clogging of a plate condenser of a domestic dishwasher

Abstract

A household dishwasher includes a receiving compartment for receiving an item to be washed, a pump sump, and a heat pump assembly through which, during operation, a heat transfer medium flows. The heat pump assembly includes a plate condenser configured to enable a transfer of heat from the heat transfer medium to a washing liquor circulating in the household dishwasher. A spray assembly supplies washing liquor to the item to be washed. A first flow path extends from the pump sump to the spray assembly for conducting the washing liquor, and a second flow path extends from the pump sump to the plate condenser. Means are provided to prevent or hinder foreign matter that is swept along with the washing liquor from adhering to a washing-liquor-facing surface of the plate condenser, or to detach foreign matter adhering to the washing-liquor-facing surface from said surface.

Claims

1. A household dishwasher, comprising: a receiving compartment for receiving an item to be washed; a pump sump; a heat pump assembly through which, during operation, a heat transfer medium flows, said heat pump assembly comprising a plate condenser configured to enable a transfer of heat from the heat transfer medium to a washing liquor circulating in the household dishwasher; a spray assembly configured to supply washing liquor to the item to be washed; a first flow path extending from the pump sump to the spray assembly for conducting the washing liquor; a second flow path extending from the pump sump to the plate condenser; means for preventing or hindering foreign matter that is swept along with the washing liquor from adhering to a washing-liquor-facing surface of the plate condenser, the means including a filter assembly positioned within the second flow path and positioned external to and between the pump sump and the plate condenser to trap the foreign matter; and means for removably attaching the filter assembly to the receiving compartment, the filter assembly being removable for external cleaning of the filter assembly.

2. The household dishwasher of claim 1, wherein the means for preventing or hindering foreign matter further comprises a conveying means configured to temporarily increase or lower a flow speed of the washing liquor flowing through the plate condenser or to change a flow direction of the washing liquor flowing through the plate condenser.

3. The household dishwasher of claim 2, wherein the conveying means is a pump.

4. The household dishwasher of claim 2, wherein the conveying means is configured to reverse the flow direction of the washing liquor flowing through the plate condenser.

5. The household dishwasher of claim 2, wherein the conveying means is integrated into the second flow path.

6. The household dishwasher of claim 1, wherein the means for preventing or hindering foreign matter further comprises a bypass configured to change a flow path of the washing liquor flowing into the plate condenser.

7. The household dishwasher of claim 1, wherein the means for preventing or hindering foreign matter further comprises a heating device configured to heat the washing liquor flowing into the plate condenser to a temperature of at least 60° C. before entering the plate condenser or to heat the washing liquor within the plate condenser to a temperature of at least 60° C.

8. The household dishwasher of claim 7, wherein the heating device is embodied as an electrical heater.

9. The household dishwasher of claim 7, wherein the plate condenser is constructed to form the heating device.

10. The household dishwasher of claim 1, wherein the filter assembly is provided at an inlet of the plate condenser, or configured to cover an inlet of the second flow path.

11. The household dishwasher of claim 1, wherein the filter assembly has a mesh size of between 2 mm and 8 mm.

12. The household dishwasher of claim 1, wherein the means for preventing or hindering foreign matter further comprises a gap with a distance of at least 4.5 mm between two adjacent walls of the plate condenser, between which a flow channel for flow-through of washing liquor to be heated is established during operation of the heat pump assembly.

13. The household dishwasher of claim 1, wherein the means for preventing or hindering foreign matter further comprises a gap with a distance of at least 4.5 mm between two adjacent connecting regions between two adjacent walls of the plate condenser, thereby defining a flow channel for flow-through of washing liquor to be heated during operation of the heat pump assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These are schematic principle sketches in which:

(2) FIG. 1 shows a section of a household dishwasher according to the invention,

(3) FIG. 2 shows a section of a further household dishwasher according to the invention,

(4) FIG. 3 shows a longitudinal section through two plates of a plate condenser (top) and a top view of a surface of a plate of a plate condenser facing the washing liquor (bottom), along which washing liquor flows in a predetermined flow direction in order to be heated, and

(5) FIG. 4 shows a top view of the surface of the plate facing the washing liquor from FIG. 3, along which the washing liquor flows in the opposite direction to FIG. 3 during a phase for the elimination of foreign matter.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

(6) In the following figures, corresponding parts are provided with the same reference characters. Only those elements of a household dishwasher 1 are described and provided with reference characters that are necessary to the understanding of the invention. Of course the household dishwasher 1 according to the invention can comprise further parts and assemblies.

(7) The household dishwasher 1 according to the invention comprises several walls 16 (in the form of side walls, one rear wall, one ceiling wall and one base wall), which delimit an internal receiving compartment 2, which serves to receive items to be washed 3. The sections shown are of course surrounded by a housing with a door (not shown).

(8) To receive the items to be washed 3, the receiving compartment 2 contains for example one or several racks 21. One or several spray assemblies 7 are also present, which can be used to supply a washing liquor 6, in other words water or water with detergent and/or rinse aid, to the items to be washed 3, for example during a cleaning or rinsing step of a washing program. In the example shown, the spray assembly 7 comprises a section assigned to the upper rack 21 and a section assigned to the lower rack 21. It can have in particular an upper rotatably mounted spray arm and a lower rotatably mounted spray arm.

(9) For freshwater supply purposes, the household dishwasher 1 is connected via a water supply (not shown) to a freshwater network (also not shown). A drain 17 is also present, via which the household dishwasher 1 is connected to a wastewater network (not shown) and via which dirty washing liquor 6 can be conveyed out of a pump sump 4 of the household dishwasher 1 arranged in the region of the base wall.

(10) Before the washing liquor 6 is removed via the drain 17, however, it is generally circulated several times and supplied via the spray assembly 7 to the items to be washed 3 in order to detach foreign matter 22. For this purpose, the household dishwasher 1 comprises a first flow path 8 extending from the pump sump 4 to the spray assembly 7 or the sections thereof specified above.

(11) The first flow path 8 preferably comprises one or several line sections 12, for example in the form of pipes. A flow divider gate (not shown) can be arranged between a conveying device 10 and the said sections of the spray assembly 7, via which the volume flow of the washing liquor 6 to the individual sections of the spray assembly 7 is determined or, in the case of an active flow divider gate, can be regulated by way of a control and/or regulating unit (not shown).

(12) The first flow path 8 preferably begins in the region of a first inlet 13 in the pump sump 4 and extends to the washing liquor outlet openings of the spray assembly 7. It comprises the said conveying device 10 for the washing liquor 6.

(13) Also provided is a second flow path 9 with an inlet 14 in the pump sump 4 and an outlet 15 in the pump sump 4 (as shown) or in the region of a wall 16 delimiting the receiving compartment 2 (not shown). It has a conveying means 23 for the washing liquor 6.

(14) The conveying device 11 and the conveying means 23 are preferably a fluid pump, the conveying power of which can be adjusted using the control and/or regulating unit.

(15) In order to heat the washing liquor 6, the household dishwasher 1 comprises a heat pump assembly with an evaporator, a compressor, an expansion element and a condenser in the form of a plate condenser 5, wherein the three components first mentioned are not shown. These can therefore be arranged at any location. The evaporator can preferably be arranged in the region of an outer side of the said walls 16. During the one or several program sub-steps with washing fluid to be heated, for example during the cleaning or rinsing step of a dishwashing program to be carried out, it can in particular be arranged such that it is thermally isolated from the receiving compartment, for example by means of at least one thermal insulation layer, in order that heat losses from the receiving compartment during the one or several program sub-steps with washing liquor to be heated, for example during the cleaning or rinsing step, are to a large extent avoided. The thermal insulation is advantageously embodied or deactivatable in such a way that, during the drying step of the dishwashing program to be carried out, a heat transfer from the receiving compartment to the heat transfer medium is enabled when the latter passes through the evaporator. This is particularly advantageous during the drying step, since water vapor in the receiving compartment 2 is to condense in this step. The evaporator is preferably a plate condenser.

(16) If the compressor is now activated, the heat transfer medium present in gaseous form in the region of the compressor is compressed. The compressed heat transfer medium flows onward to the plate condenser 5, where it gives off heat and in the process condenses. The liquid heat transfer medium then reaches the expansion element, which effects a reduction in pressure. Subsequently, the heat transfer medium, still wholly or partially in liquid form, flows to the evaporator. There it extracts heat from the environment and/or a water tank, in particular freshwater infeed tank (not shown in the drawing for this exemplary embodiment) and is hereby transformed into the gaseous aggregate state in order to return ultimately to the compressor, so that the heat transfer medium cycle is closed. The plate condenser 5 comprises on the inlet side a washing liquor inlet 26 for the washing liquid or washing liquor to be heated which is fed in from the pump sump 4 and on the outlet side a washing liquor outlet 15 for feeding the washing liquid heated in the plate condenser 5 back into the pump sump 4 and/or to another location in the receiving compartment 2. Here, the plate condenser 5 is connected via a first heat transfer medium line 18 to the compressor and via a second heat transfer medium line 19 to the expansion element of the heat pump assembly. The first heat transfer medium line 18 feeds the heat transfer medium into at least one flow-through channel of at least one plate of the plate condenser. After passing through the multiplicity of flow-through channels of the plates of the plate condenser, the heat transfer medium leaves the latter via the second heat transfer medium line 19. Washing liquor inlet 26 and washing liquor outlet 15 of the plate condenser 5 are indicated in FIGS. 3 and 4.

(17) In the example shown, the plate condenser 5 is arranged below the base wall. It can of course also be positioned in the region of the ceiling wall or one of the side walls.

(18) In order to transport the washing liquor 6 to the plate condenser 5, the household dishwasher 1 comprises the second flow path 9 for the washing liquor 6, which extends from a second inlet 14 in the pump sump 4 to the plate condenser 5 and from there to an outlet 28.

(19) In the pump sump 4, the household dishwasher can have a first inlet 13 into the first flow path 8 and a second inlet 14 into the second flow path (FIG. 1). It is also conceivable that a shared inlet 29 is present (FIG. 2), via which the washing liquor 6 is initially extracted from the pump sump 4. The washing liquor 6 is finally conveyed onward via a corresponding flow divider gate (not shown) either into the first flow path 8 or into the second flow path 9 or alternatively proportionately into both flow paths 8, 9 and ultimately reaches the spray assemblies 7 and/or the plate condenser 5.

(20) The conveying direction of the conveying device 10 and of the conveying means 23 are indicated by an arrow with the reference character F.

(21) If, in the respective washing program to be carried out, a washing step such as a cleaning step or rinsing step is performed while the washing liquor 6 is being heated by means of the heat pump assembly, then the washing liquor 6 in the pump sump 4 is sucked by means of the conveying device 10 into the second inlet 14 of the second flow path 9 or the shared inlet 29 and transported to the plate condenser 5. There it is heated by the latter and is returned by the conveying means 23 to the pump sump 4 via the outlet 28 of the second flow path 9.

(22) In order now to prevent foreign matter 22 present in the washing liquor 6 from adhering within the plate condenser 5 or at least to ensure that a corresponding adherence is hindered or any foreign matter 22 present is removed once again from the plate condenser 5, the household dishwasher 1 now comprises at least one means with which this object can be achieved.

(23) FIG. 1 shows a solution in which a filter assembly 24 is integrated into the second flow path 9, through which the washing liquor 6 flows before reaching the plate condenser 5. Here the filter assembly 24 has a mesh size that traps particles up to a specified particle size.

(24) The filter assembly 24 is preferably positioned at a location which is accessible via the receiving compartment 2 or from the outer side of the household dishwasher 1 (if necessary after removing one or several panels) so that the filter assembly 24 can be removed and cleaned easily by an operator.

(25) In addition thereto or independently thereof, the household dishwasher 1 can have a special cleaning program, in which the flow speed of the washing liquor 6 passing through the filter assembly 24 can be increased or reversed in order to flush out of the filter assembly 24 any foreign matter 22 trapped therein and thus to clean the filter assembly 24.

(26) The filter device 24 does not have to be integrated into the second flow path 9. Such a filter device 24 is also conceivable directly in the region of the second inlet or entry 14 or of the shared inlet or entry 29. In particular, the filter assembly 24 can alternatively already be provided at the inlet 14 of the second flow path 9.

(27) FIG. 2 shows a further embodiment. Here, instead of the filter device 24 (which could of course also be present), an electrical heater 25 is provided, which heats the washing liquor 6 to a specified temperature before it enters the plate condenser 5. The heated washing liquor 6 finally causes in particular fatty deposits within the plate condenser 5 to become detached.

(28) The electrical heater 25 is preferably activated only during selected program steps of a washing program or during a separate plate condenser cleaning program.

(29) It can also be operated during a conventional cleaning step or a rinsing step of a washing program in order to support the heating of the washing liquor 6, which takes place mainly using the heat pump assembly.

(30) Finally, FIG. 3 shows a partially cut section of a plate condenser 5, wherein the upper view shows a cut side view and the lower view a cut top view. The plate condenser 5 comprises, as is known from the prior art, several plates 30, which are arranged in layers with defined spacing. Each two adjacent plates arranged at a distance from one another are in contact with one another via connection regions 11 and form a cavity 31 for the washing fluid to be fed in and heated. On the side of the first and second plate delimiting the respective cavity 31 and facing away therefrom, the heat transfer medium of the heat pump assembly is preferably guided in a channel or cavity.

(31) If washing liquor 6 is now introduced via the washing liquor inlet 26 into the plate condenser 5, it flows through the respective cavity 31. As it does so, it comes into direct contact with the surfaces 27 of the plate condenser 5 which face the washing liquor 6, so that there is always the danger here of foreign matter 22 adhering or becoming trapped in the connecting regions 11, as shown in the lower part of FIG. 3. This in turn results in a deterioration of the heat transfer through the plates 30 and thus the degree of efficiency of the plate condenser 5. After flowing through all cavities of the plate condenser, the washing fluid thereby heated leaves the plate condenser 5 once again via the washing liquor outlet 15 thereof.

(32) Viewed from the respective cavity 31, the heat transfer medium of the heat pump assembly is guided behind the first plate 30 delimiting the cavity 31 and behind the second plate 30 arranged at a distance therefrom and delimiting the cavity, and gives off heat to the washing liquor 6, which is then pumped in the heated state into the pump sump 4 and from there to the spray assemblies 7. Finally, it reaches the items to be washed 3, where it detaches foreign matter 22 therefrom.

(33) As FIG. 3 shows, in particular elongated items of foreign matter 22 can adhere to the connecting regions 11.

(34) In order to detach these, it can be provided that the flow direction of the washing liquor 6 passing through the plate condenser 5 is reversed at regular intervals. As a result, adhering foreign matter 22 is detached and carried out of the plate condenser 5. This is finally shown in FIG. 4.

(35) For this purpose, the conveying direction of the conveying means 23 is temporarily reversed, for example.

(36) A means for preventing or reducing the clogging or even blockage of the plate condenser with foreign bodies or foreign matter can be provided in addition to or independently of the aforegoing variants in particular by the distance or width D of the gap between two adjacent walls or plates 30 of the plate condenser in each case, between which a flow channel SK for the flow-through of washing liquor to be heated is present during operation of the heat pump assembly, being selected to be at least equal to 4.5 mm. In general terms, this gap width for the flow-through of washing liquor between two adjacent plates of the condenser in each case is selected to be approximately equal to or preferably greater than the smallest occurring cross-section width of a pump, for example 23 or 10, in particular circulating pump, arranged in the flow-through channel, which cross-section still permits a sufficient passage of foreign bodies.

(37) The same dimensioning also applies in particular to the transverse distance W between two adjacent connecting points 11 in each case, which are provided between two adjacent walls or plates 30 of the plate condenser 5 in each case in order to hold said walls together (transversely, in particular perpendicularly to the respective plate or wall plane), between which walls a flow channel SK is present for the flow-through of washing liquor to be heated during operation of the heat pump assembly.

(38) Moreover, the present invention is not restricted to the exemplary embodiment shown. Rather, all combinations of the individual features described, as shown or described in the claims, the description and the figures, and insofar as a corresponding combination appears technically possible or expedient, are the subject matter of the invention.

LIST OF REFERENCE CHARACTERS

(39) 1. Household dishwasher

(40) 2. Receiving compartment

(41) 3. Items to be washed

(42) 4. Pump sump

(43) 5. Plate condenser

(44) 6. Washing liquor

(45) 7. Spray assembly

(46) 8. First flow path

(47) 9. Second flow path

(48) 10. Conveying device

(49) 11. Connecting regions

(50) 12. Line section

(51) 13. First inlet

(52) 14. Second inlet

(53) 15. Washing liquor outlet

(54) 16. Wall

(55) 17. Drain

(56) 18. First heat transfer medium line

(57) 19. Second heat transfer medium line

(58) 20. Washing liquor outlet

(59) 21. Rack

(60) 22. Foreign matter

(61) 23. Conveying means

(62) 24. Filter assembly

(63) 25. Electrical heater

(64) 26. Washing liquor inlet

(65) 27. Surface of the plate condenser facing the washing liquor

(66) 28. Outlet

(67) 29. Shared inlet

(68) 30. Plate

(69) 31. Cavity

(70) F Conveying direction

(71) S Flow direction

(72) SK Flow channel for washing liquor to be heated

(73) D Distance between two adjacent walls of the plate condenser, between which a flow channel for washing liquor to be heated is present

(74) W Distance between each two adjacent connecting points 11 provided in each case between two adjacent walls of the plate condenser