dishwasher

Abstract

Dishwasher (1), in particular a household dishwasher, with a wash chamber (3) providing a wash chamber (4) for receiving items to be cleaned, a collection pot (10) into which the wash chamber (3) empties, a circulation pump (11) fluidically connected to the collection pot (10) and a fresh water line (19) for connection to a fresh water supply point (20), characterized in that a first supply line (25) opening into a first fresh water inlet (26) and a second supply line (27) opening into a second fresh water inlet (28) are provided, which are connected to the fresh water line (19) via a valve (29) fluidically, wherein the collection pot (10) has the first fresh water inlet (26) and wherein the second fresh water inlet (28) is provided on the pressure side of the circulation pump (11).

Description

[0001] The invention relates to a dishwasher, in particular a household dishwasher, comprising a wash chamber providing a wash area for receiving items to be cleaned, a collection pot into which the wash chamber empties, a circulation pump connected to the collection pot, and a fresh water line for connection to a fresh water supply point. The invention further relates to a method for introducing fresh water into a dishwasher of the type mentioned above.

[0002] Dishwashers of the type mentioned above are well known from the prior art, as for example from US 2010 / 0043847 A1.

[0003] Conventional dishwashers have a wash chamber that provides a washing area. This chamber is accessible to the user via a loading opening, which can be sealed fluid-tight by means of a pivoting wash chamber door. Under normal operating conditions, the wash chamber serves to hold items to be cleaned, such as dishes, cutlery, and / or the like.

[0004] To spray the items to be cleaned with cleaning fluid, the so-called wash liquor, the dishwasher has a spray system inside the wash tub. This spray system typically provides rotating spray arms, usually two or three of which are provided. Under normal operating conditions, the items to be cleaned are filled with the wash liquor by means of rotating spray arms.

[0005] The cleaning solution dispensed by the spray system during operation comes into contact with the items to be cleaned and then collects in a reservoir into which the wash tank empties. The reservoir is connected to a circulation pump on one side and a drain pump on the other. The circulation pump supplies the spray system with cleaning solution and, under normal operating conditions, circulates the cleaning fluid supplied to the dishwasher. At the end of a wash cycle, the drain pump removes and discards the cleaning solution.

[0006] At the start of a wash cycle, fresh water is supplied to the dishwasher from a fresh water outlet. The dishwasher's reservoir has a fresh water inlet for this purpose, which is connected to the fresh water outlet. As soon as the reservoir is filled with enough fresh water for the circulation pump to operate correctly, the circulation pump starts, and the spray arms are supplied with wash water. The dishwasher has a fresh water line for this connection to the fresh water outlet. This fresh water line can be, for example, a hose.The public water network typically serves as the fresh water supply point, possibly with the interposition of machine-side components such as water softening devices, water storage tanks and / or the like.

[0007] Due to its design, even after the drain pump has pumped out the wash water as intended at the end of a wash cycle, a residual amount of wash water remains in the pump housings of the circulation pump and the drain pump, in the sump, and in the lines connecting the sump and the circulation pump on the one hand, and the sump and the drain pump on the other. If a new wash cycle is then started by introducing fresh water, the fresh water mixes with the residual wash water still present in the dishwasher. This leads to an unwanted carryover of alkaline solutions and / or chlorides into the newly started wash cycle.This can adversely affect corrosion, both on dishwasher components such as the heating element, pump housings, supply lines and / or the like, and on the items being cleaned.

[0008] To counteract such alkaline and / or chloride carryover, it is known from EP 2 759 244 B1 to introduce fresh water into the dishwasher after a properly completed cleaning cycle, particularly to flush the circulation pump and the sump. EP 2 759 244 B1 proposes introducing fresh water into the circulation pump while the pump is switched off, i.e., without pumping. The fresh water introduced into the circulation pump flows through it and from there, via the corresponding connecting lines, directly to the sump. From there, it can be pumped out by switching on the drain pump. As a result of the fresh water introduction, the residual wash water in the dishwasher is not merely mixed with the fresh water, but is largely expelled by displacement.This allows for almost complete disposal of the residual rinse water with comparatively little fresh water, so that virtually no alkaline and / or chloride residues are carried over into a subsequent rinsing program.

[0009] According to the design previously known from EP 2 759 244 B1, the fresh water inlet is routed from the collection tank to the circulation pump. The fresh water inlet is therefore no longer supplied by the collection tank, but by the circulation pump, so that in operation the circulation pump is directly supplied with fresh water.

[0010] Although the design, previously known from EP 2 759 244 B1, has proven itself in everyday practical use, there is room for improvement. It has been found that, due to the pressure of the circulation pump during normal operation, dishwashing liquid can flow back into the fresh water line connected to the circulation pump. This is considered a disadvantage, as it can lead to unwanted contamination within the fresh water line. Therefore, the object of the invention is to further develop a dishwasher of this type in such a way that, while simultaneously allowing for the rinsing of the alkaline and / or chloride section, improved operation of the dishwasher is permitted.

[0011] To solve this problem, the invention proposes a dishwasher of the type mentioned at the outset, which is characterized in that a first supply line leading into a first fresh water inlet and a second supply line leading into a second fresh water inlet are provided, which are connected to the fresh water line via an intermediate valve, wherein the collection pot has the first fresh water inlet and wherein the second fresh water inlet is provided on the pressure side of the circulation pump.

[0012] Furthermore, a method for introducing fresh water into a dishwasher of the type according to the invention is proposed, in which the fresh water is supplied to the dishwasher from a fresh water supply point, wherein the fresh water is directed to the collection tank, preferably without a pump, depending on the selectable valve position either to carry out a washing program directly via the first fresh water inlet or to carry out a rinsing of the dishwasher indirectly via the second fresh water inlet with the fluid-technical interposition of the circulation pump.

[0013] According to the invention, a first fresh water inlet and a second fresh water inlet are provided. The collection tank has the first fresh water inlet. The second fresh water inlet is located on the pressure side of the circulation pump. Thus, in contrast to the prior art according to EP 2 759 244 B1, there is not just a single fresh water inlet. This advantageously allows a distinction to be made between running a wash program and rinsing the dishwasher. It is provided that fresh water is supplied during a wash program via the first fresh water inlet, i.e., into the collection tank. To rinse the dishwasher for the purpose of rinsing the alkaline and / or chloride section, i.e.,The circulation pump, the collection tank and the flow path leading from the circulation pump via the collection tank to the drain pump are supplied with fresh water via the second fresh water inlet, whereby fresh water is introduced into the circulation pump on the pressure side.

[0014] Two supply lines are provided: a first supply line and a second supply line. The first supply line connects to the first fresh water inlet, and the second supply line connects to the second fresh water inlet. The two supply lines are connected to the main fresh water line via a valve. Depending on the valve position, fresh water can be supplied to either the first or the second supply line. Thus, by adjusting the valve, fresh water can be fed either into the collection tank via the first fresh water inlet or into the circulation pump via the second fresh water inlet.

[0015] The inventive design proves to be advantageous compared to the prior art for several reasons. Firstly, a distinction can be made between the washing operation on the one hand and the cleaning of the alkaline and / or chloride section, i.e., the circulation pump, the collection tank, and the flow path leading from the circulation pump via the collection tank to the drain pump, on the other. During the intended washing operation, the collection tank is filled with fresh water in a manner known per se. As soon as the quantity of fresh water required for the proper operation of the circulation pump has been introduced into the collection tank, the circulation pump is switched on. This pump draws in the fresh water introduced into the collection tank via the flow-related connection between the circulation pump and the collection tank and, during the circulating operation, discharges it into the wash chamber via the spray arms of the dishwasher.

[0016] To expel residual water and clean the alkaline and / or chloride section, the circulation pump is supplied with fresh water via its pressure side. When the circulation pump is not running, i.e., when the pump is idle, the fresh water supplied to the pressure side can pass through the pump and flow into the collection tank via the flow connection. This process, occurring against the flow direction during the flushing cycle, rinses the pump housing, the flow connection between the pump and the collection tank, and the collection tank itself, cleaning these components of alkaline and / or chloride residues. Simultaneously with the supply of fresh water to the circulation pump, the drain pump, which is connected to the collection tank, can be switched on, allowing the pumping out of the mixed water of fresh and residual water that has accumulated in the collection tank.

[0017] This results in a minimization of alkali and / or chloride carryover. In particular, the circulation pump impeller and the tubular heating element integrated into the circulation pump are cleaned. During the standard flushing program, the alkali and / or chloride path is flushed in reverse flow direction, which improves the cleaning of filters, especially microfilters.

[0018] The supply lines leading into the fresh water inlets are connected to the fresh water line via a valve. Depending on the valve position, either one supply line or the other is fed, which can be advantageously adjusted, for example, depending on the wash program, by means of a control unit on the dishwasher. A further advantage of the valve arrangement is that it prevents unwanted backflow of wash water into the fresh water line and components connected to it on the other side, particularly due to the circulation pump pressure that develops during normal operation.

[0019] The design according to the invention ensures that, during the dishwasher's wash cycle, the entire alkaline and / or chloride section is thoroughly rinsed, thus removing as much residual liquid as possible and preventing unwanted carryover of alkaline and / or chloride into subsequent wash programs. Fresh water is supplied to the circulation pump via the pressure side, allowing the alkaline and / or chloride section to be rinsed without the pump running. Alternatively, the pump can be operated in reverse at the lowest possible speed. This improves the cleaning, particularly of the circulation pump housing.

[0020] During normal operation of a wash program, the sump is filled with fresh water. In this case, the flow connection between the fresh water line and the circulation pump—that is, the flow connection via the second supply line—is closed at the valve. This ensures that no wash water is forced into the fresh water line by the circulation pump via the second supply line. Overall, this ensures safe and proper operation of the dishwasher, both during a simple rinse cycle and during a wash program.

[0021] According to a further feature of the invention, the valve is a 3-way valve to which the fresh water line and the two supply lines are connected. Accordingly, a common valve is used for the fresh water line and the two supply lines, whereby, depending on the valve's position, either the first supply line or the second supply line is supplied. The valve can therefore be configured such that there is either a flow connection between the fresh water line and the first supply line or between the fresh water line and the second supply line. Consequently, fresh water is supplied to either the first or the second fresh water inlet.

[0022] According to a further feature of the invention, a shut-off valve is arranged upstream of the valve in terms of flow direction. The shut-off valve serves to block the fresh water supply. Such a blockage is carried out, for example, after fresh water has been introduced.

[0023] According to a further feature of the invention, the valve and the shut-off valve are combined to form a single valve assembly. Thus, instead of two flow-related valves connected in series, a single, integrated valve assembly is used. Such a one-piece design offers particular advantages for manufacturers during assembly.

[0024] According to a particular feature, the invention is characterized by a spray arm arranged within the wash tank and fluidically connected to the circulation pump for spraying the items to be cleaned with washing solution, wherein the fluid connection between the circulation pump and the spray arm includes the second fresh water inlet. Thus, in contrast to the prior art according to EP 2 759 244 B1, the fresh water inlet is not located directly on the circulation pump, but is arranged on the pressure side of the circulation pump and is preferably provided by the fluid connection between the circulation pump on the one hand and the spray arm on the other. Advantageously, the second fresh water inlet is located at the lowest point in the dishwasher's water supply system with respect to the dishwasher's overall height.This advantageous design ensures that, during flushing, at least partial cleaning of the flow path between the circulation pump and the spray arm occurs. Furthermore, the design of the second fresh water inlet in the flow path between the circulation pump and the spray arm guarantees complete cleaning of the pump housing in the inlet area of ​​this path. The design of the second fresh water inlet in the flow path between the circulation pump and the spray arm thus results in an overall positive effect: even more thorough flushing of the alkali and / or chloride section compared to EP 2 759 244 B1. This leads to a more efficient process and ultimately improved cleaning results.

[0025] According to a further feature of the invention, fresh water can be introduced into the collection tank via either the first or the second fresh water inlet, depending on the selectable position of the valve. The valve position is preferably determined by the dishwasher's control electronics. The valve position is selected based on whether a standard wash program or a standard rinse of the alkaline and / or chloride section is to be performed. Depending on the valve position, this results in the flow being enabled by either the first or the second fresh water inlet.

[0026] According to a further feature of the invention, the process involves operating a drain pump connected to the collection tank, at least temporarily, simultaneously with the circulation pump, and pumping out the mixed water of fresh and residual water that accumulates in the collection tank. This method applies to the flushing operation. Accordingly, fresh water is supplied to the pressure side of the circulation pump, which flows into the collection tank without the circulation pump being operated. The mixed water that forms in the collection tank is then pumped out by the drain pump. Alternatively, instead of operating without the pump, the circulation pump can also be operated, preferably at the lowest possible speed, for example, at idle speed. In this case, the circulation pump preferably operates in reverse, so that the fresh water supplied on the pressure side is conveyed to the suction side of the circulation pump.

[0027] Further advantages and features of the invention will become apparent from the following description with reference to the figures. These show Fig. 1 in schematic view a dishwasher according to the invention; Fig. 2 in schematic principle representation a dishwasher according to the invention; Fig. 3 in schematic principle representation a preferred embodiment of the dishwasher according to the invention; Fig. Figure 4 shows in a schematic perspective representation the collection pot and the circulation pump connected to it in terms of fluid dynamics of a dishwasher according to the invention.

[0028] Fig. Figure 1 shows a dishwasher 1 according to the invention in a purely schematic representation.

[0029] The dishwasher 1 has a housing 2 which, among other things, accommodates a wash tub 3. The wash tub 3 in turn provides a wash chamber 4 which, in its intended use, serves to hold the items to be cleaned.

[0030] A spray device 5, located within the wash tank 3, serves to supply the items to be cleaned with washing solution. Preferably, such a spray device 5 has at least two different spray elements, in particular spray arms 6 and 7, each rotatably arranged within the wash tank 3. In the illustrated embodiment, the spray device 5 has an upper spray arm 6 and a lower spray arm 7. Typically, a dishwasher of this type has three spray arms, namely an upper and a lower spray arm, and a middle spray arm, as exemplified in Fig. 3 is shown.

[0031] The wash container 3 is accessible from the user via a loading opening 8, which can be closed in a fluid-tight manner by means of a pivotably mounted wash chamber door 9.

[0032] The flushing tank 3, or the flushing chamber 4 provided by the flushing tank 3, leads into a [details of which are in] Fig. 4. A collection tank 10, shown in more detail below, contains a circulation pump 11 and a discharge pump 12, each connected to this collection tank 10 via a flow-related connection. For this purpose, a flow-related connection 15 is provided between the circulation pump 11 and the collection tank 10, and a flow-related connection 13 is provided between the discharge pump 12 and the collection tank 10.

[0033] The circulation pump 11 is connected to the spray arms 6 and 7 of the spray device 5 via corresponding flow connections 16 and 17, with the flow connection 16 leading from the circulation pump 11 to the lower spray arm 7 and the flow connection 17 leading from the circulation pump 11 to the upper spray arm 6. The spray device 5 may also have additional spray arms or other spray elements (not shown) which are connected to the circulation pump via further flow connections.

[0034] In the intended use case, the circulation pump 11 can supply either the flow connection 16 leading to the lower spray arm 7 or the flow connection 17 leading to the upper spray arm 6 with flushing fluid.

[0035] After completion of a rinsing program, the used rinsing solution is pumped out by means of the drain pump 12, for which purpose the drain pump 12 is connected to a line 14 which typically leads into the public sewer network and discharges the used rinsing solution in accordance with arrow 18.

[0036] Fig. Figure 2 shows the further construction of the dishwasher 1 according to the invention. A fresh water supply point 20 is provided, which can, for example, be an access point to the public water network, possibly with an intermediate water reservoir on the machine side and / or the like. Crucially, fresh water is supplied via the fresh water supply point 20 through the fresh water line 19. In the illustrated embodiment, a shut-off valve 24 and a fresh water softening device 22 are also provided. In the intended use, fresh water thus flows from the fresh water supply point 20 via the line 21 to the fresh water softening device 22 and from there via the line 23 to the valve 24, which separates the line 23 from the fresh water line 19.In the intended use case, the shut-off valve 24 is open, so that fresh water can enter the fresh water line 19 via the aforementioned pipe path.

[0037] Two supply lines 25 and 27 are connected to the fresh water line 19 via a 3-way valve 29. Depending on the position of the valve 29, fresh water can be supplied to either the first supply line 25 or the second supply line 27.

[0038] The first supply line 25 leads into a first fresh water inlet 26, which is provided by the collection tank 10. With the valve 29 in the appropriate position, the collection tank 10 is thus supplied with fresh water via the fresh water line 19 and the first supply line 25, which is directly connected to it in terms of flow direction.

[0039] The second supply line 27 leads into a second fresh water inlet 28. This second fresh water inlet 28 is located within the flow connection 16 between the circulation pump 11 and the spray arm 7. With the valve 29 in the appropriate position, the circulation pump 11 is supplied with fresh water via the fresh water line 19, the second supply line 27 connected to it, and at least partially via the flow connection 16 between the circulation pump 11 and the spray arm 7. The flow connection 16 between the circulation pump 11 and the spray arm 7 is located on the pressure side of the circulation pump 11, thus ensuring that the circulation pump 11 is supplied with fresh water on the pressure side.

[0040] Fig. Figure 3 illustrates the situation already explained above with a further schematic diagram. As this diagram shows, a first fresh water inlet 26 is provided on the collection tank side and a second fresh water inlet 28 is provided on the circulation pump side. In the intended operating condition of dishwashing, fresh water is supplied to the collection tank 10 via the first supply line 25 at the beginning of a wash program. As soon as a sufficient amount of fresh water has been supplied, the circulation pump 11 is started and the supplied fresh water is circulated, with the circulation pump 11 supplying fresh water to either the upper spray arm 6 via the flow connection 17 or the lower spray arm 7 via the flow connection 16.The fresh water introduced into the washing container 3 in this way serves to clean the items being washed and collects as a washing liquor in the collection pot 10, from where the washing liquor is then guided again to the circulation pump 11 via the flow connection 15 and thus kept in circulation.

[0041] After completion of a properly executed rinsing program, alkaline and / or chloride residues remain, particularly in the collection tank 10 and in the housing of the circulation pump 11. These residues must be removed to prevent carryover into a subsequent program step and / or a subsequent rinsing program. According to the invention, a flushing process is therefore provided, which cleans the alkaline and / or chloride section, i.e., in particular, the collection tank 10 and the housings of the pumps 11 and 12 are freed from alkaline and / or chloride residues.

[0042] The rinsing process according to the invention provides that fresh water is supplied to the dishwasher 1 from the fresh water supply point 20. The fresh water is fed to the pump 11 on the pressure side and from there, without the need for a pump, into the collection tank 10, which is fluidically connected to the circulation pump 11. Fresh water is supplied to the circulation pump via the second supply line 27 and the second fresh water inlet 28, into which the second supply line 27 opens, when the valve 29 is in the appropriate position. Preferably, the drain pump 12, which is fluidically connected to the collection tank 10, is operated at least intermittently while the circulation pump 11 is being supplied with fresh water on the pressure side, so that the mixed water of fresh and residual water accumulating in the collection tank 10 is pumped out.

[0043] Such a flushing process is carried out with a fresh water quantity of, for example, 150 ml. This small amount of water is sufficient to largely remove unwanted alkali and / or chloride residues from the alkali and / or chloride section. Alternatively, a larger amount of fresh water can be used for flushing, and / or the flushing step can be repeated several times, for example, five times, resulting in a total fresh water consumption of 750 ml at 150 ml per flush. This water consumption is considerably lower than that of a conventional intermediate flush.

[0044] A particular advantage of the method according to the invention lies, among other things, in the fact that only the alkaline and / or chloride section to be cleaned is supplied with water. Fresh water is not supplied to the wash tank 3 and / or any items that may be located therein, as occurs during the intermediate rinse in a conventional program sequence. This has the advantage that there is virtually no heat loss from the dishwasher 1, so that less energy is required to reheat the wash liquor in subsequent wash program steps. The method according to the invention makes it possible to completely dispense with a conventional intermediate rinse step, while still ensuring that unwanted alkaline and / or chloride residues are removed and not carried over into a subsequent wash program step and / or a subsequent wash program.

[0045] As can be seen in particular from Fig. As shown in section 4, the design of the second fresh water inlet 28 in the flow-related connection 16 between the circulation pump 11 and the collection tank 10 ensures that, with respect to the height at the dishwasher's installation location, the lowest possible inlet point is selected relative to the dishwasher's water supply system 1. This means that during operation, the entire path from the inlet point through the circulation pump 11, via the collection tank 10, to the drain pump 12 is flushed with fresh water. This minimizes the carryover of alkaline solutions and / or chlorides into the next wash cycle and / or wash program. Reference sign 1 dishwasher 2 cases 3 washing containers 4. Dishwashing area 5 Spray device 6 upper spray arm 7 lower spray arm 8 Feed opening 9 Dishwashing area door 10 Collection pot 11 Circulation pump 12 Drain pump 13 fluidic connection 14 Management 15 fluidic connections 16 fluidic connections 17 fluidic connection 18 Arrow 19 Fresh water pipe 20 Fresh water dispensing point 21 Management 22 Fresh water softening unit 23 Management 24 shut-off valve 25 first feed line 26 first fresh water inlet 27 second feed line 28 second fresh water inlet 29 3-way valve

Claims

[1] Dishwasher (1), in particular a household dishwasher, comprising a wash chamber (3) providing a wash chamber (4) for receiving items to be cleaned, a collection pot (10) into which the wash chamber (3) empties, a circulation pump (11) connected to the collection pot (10) in terms of flow technology and a fresh water line (19) for connection to a fresh water supply point (20), characterized by , that a first supply line (25) opening into a first fresh water inlet (26) and a second supply line (27) opening into a second fresh water inlet (28) are provided, which are connected to the fresh water line (19) via a flow-technical intermediate valve (29), wherein the collection tank (10) has the first fresh water inlet (26) and wherein the second fresh water inlet (28) is provided on the pressure side of the circulation pump (11). [2] Dishwasher (1) according to claim 1, characterized by, that the valve (29) is a 3-way valve to which the fresh water line (19) and the two supply lines (25, 27) are connected. [3] Dishwasher (1) according to claim 1 or 2, characterized by , that a shut-off valve (24) is fluidically connected upstream of the valve (29). [4] Dishwasher (1) according to claim 3, characterized by , that the valve (29) and the shut-off valve (24) are combined to form a valve assembly. [5] Dishwasher (1) according to any one of the preceding claims, characterized by a spray arm (7) arranged within the washing tank (3) and fluidically connected to the circulation pump (11) for applying washing liquor to the items to be cleaned, wherein the fluid connection (16) between the circulation pump (11) and the spray arm (7) has the second fresh water inlet (28). [6] Dishwasher (1) according to any one of the preceding claims, characterized by , that fresh water can be introduced into the collection tank (10) via the first fresh water inlet (26) or via the second fresh water inlet (28), depending on the selectable position of the valve (29). [7] Method for introducing fresh water into a dishwasher (1) according to one of the preceding claims, wherein the fresh water is supplied to the dishwasher (1) from a fresh water supply point (20), the fresh water being directed to the collection pot (10), depending on the selectable valve position, either directly via the first fresh water inlet (26) for carrying out a washing program or indirectly via the second fresh water inlet (28) for carrying out a rinsing of the dishwasher (1) with the flow-technical interposition of the circulation pump (11). [8] Method according to claim 7, characterized by , that the fresh water is supplied to the circulation pump (11) on the pressure side. [9] Method according to claim 8, characterized by , that the fresh water is introduced into the flow-technical connection (16) between the circulation pump (11) and the spray arm (7). [10] Method according to claim 7, 8 or 9, characterized by , that a drain pump (12) connected to the collection tank (10) in terms of flow technology is operated at least temporarily simultaneously with the circulation pump (11) and mixed water of fresh and residual water accumulating in the collection tank (10) is pumped out. [11] Method according to any one of the preceding claims 7 to 10, characterized by , that the circulation pump (11) is operated at an idle speed.

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