Dishwasher with clear rinsing system

Abstract

The invention relates to a dishwasher (1), in particular a commercial dishwasher (1), which is preferably designed as a program-controlled automatic dishwasher and especially in the form of a rack-type or hood-type dishwasher, wherein the dishwasher (1) has at least one treatment chamber (2) or treatment zone in which, in particular as required and preferably during a rinse cycle, a rinse liquid is sprayed or can be sprayed, wherein the dishwasher (1) has a rinse system with a rinse line system (3) and with at least one rinse nozzle system with rinse nozzles (4.1, 4.2). According to the invention, it is particularly provided that the rinse system has a backflow preventer (5) associated with the rinse line system (3), which is configured to allow the flow of at least one section of the rinse line system (3) in only one direction.

Description

[0001] The present invention relates generally to the field of commercial dishwashing.

[0002] Specifically, the invention relates to a dishwasher, in particular a commercial dishwasher, preferably designed as a program-controlled automatic dishwasher and especially in the form of a rack-type or hood-type dishwasher. However, the present invention is not limited to this type of machine. Rather, it is fundamentally conceivable that the invention could also be used in conveyor dishwashers.

[0003] Specifically, one aspect is to reduce fresh water consumption during the rinse cycle of the dishwasher, without negatively affecting the rinse result.

[0004] Automatic dishwashers are manually loaded and unloaded. This category includes the previously mentioned pass-through dishwashers, also known as hood-type dishwashers, as well as front-loading dishwashers. Front-loading dishwashers can be undercounter, countertop, or freestanding models with front loading.

[0005] A dishwasher designed as a program-controlled automatic dishwasher typically has a treatment chamber for cleaning the dishes. This treatment chamber usually contains a washing system designed as a recirculation circuit. The aforementioned wash tank is typically located below the treatment chamber, allowing liquid from the treatment chamber to flow back into it by gravity. The wash tank contains washing fluid, usually water, to which detergent can be added if necessary.

[0006] The washing system comprises a wash pump, a pipe system connected to the wash pump, and a nozzle system with at least one wash nozzle. The washing fluid in the wash tank can be pumped by the wash pump via the pipe system to the at least one wash nozzle, and sprayed through this nozzle onto the items to be cleaned in the treatment chamber. The sprayed washing fluid then flows back into the wash tank by gravity.

[0007] Conventional, program-controlled dishwashers typically operate in two main process steps: first, washing with detergent solution, and then rinsing with heated fresh water to which rinse aid has been added. The wash solution contains water and added detergent. To perform these two process steps, a commercial, program-controlled dishwasher is usually equipped with two independent, completely separate fluid systems. One of these systems is a wash fluid circuit, responsible for washing the dishes and using previously used liquid from the wash tank. The other system is a rinse fluid circuit, which typically includes a water heater to heat the fresh water.

[0008] The main purpose of rinsing with rinse aid is to remove the wash liquid from the items being washed. Additionally, the rinse aid that flows into the wash tank during the rinsing process regenerates the wash liquid in the tank.

[0009] A special type of commercial dishwasher, specifically a program-controlled model, is the hood-type dishwasher, also known as a pass-through dishwasher. Its cleaning chamber is enclosed by a hood. This hood can be raised to load the chamber and then lowered again to clean the dishes.

[0010] Conveyor dishwashers are primarily flight-type or rack conveyor dishwashers. They are typically used in commercial settings. Unlike single-tank dishwashers, where the items to be cleaned remain stationary during the cleaning process, conveyor dishwashers transport the items through various treatment zones. Conveyor dishwashers are generally designed as multi-tank machines.

[0011] A conveyor dishwasher typically has at least one pre-wash zone and at least one main wash zone, which, viewed in the direction of transport, is located after the pre-wash zone(s). Viewed in the direction of transport, after the main wash zone(s), there is usually at least one post-wash zone and at least one rinse zone downstream of the post-wash zone(s). Viewed in the direction of transport, the items being washed, either directly on the conveyor belt or held in baskets, typically pass through an inlet tunnel, the subsequent pre-wash zone(s), main wash zone(s), post-wash zone(s), rinse zone(s), and a drying zone before entering an outlet section.

[0012] Each of the aforementioned washing zones of the conveyor dishwasher is assigned a washing system, which includes a wash pump and a connected piping system (wash piping system) through which liquid is supplied to the spray nozzles of the respective washing zone. The washing liquid supplied to the spray nozzles is sprayed onto the items being washed in the respective washing zone, which are transported through the washing zones by a conveyor system of the conveyor dishwasher. Each washing zone has an associated tank in which sprayed liquid is collected and / or in which liquid is supplied to the spray nozzles of the respective zone.

[0013] In conventional conveyor dishwashers, rinse aid, in the form of fresh water (which may be pure or contain additives such as rinse aid), is sprayed onto the items being washed via the spray nozzles of the rinse zone. At least a portion of the sprayed rinse aid is transported from zone to zone via a cascade system, in the opposite direction to the transport of the items.

[0014] The sprayed rinse aid is collected in a tank (post-wash tank) in the post-wash zone. From there, it is pumped by the wash pump of the post-wash zone's washing system to the spray nozzles (post-wash nozzles). In the post-wash zone, the wash fluid is rinsed off the items being washed. The resulting liquid flows into the wash tank of at least one main wash zone, which is located upstream of the post-wash zone in the direction of item transport. Here, the liquid is typically mixed with a cleaning agent and sprayed onto the items via the nozzles (wash nozzles) of the main wash zone by a pump system (wash pump) belonging to the main wash zone's washing system. From the main wash zone's wash tank, the liquid then flows—unless another main wash zone is present—into the pre-wash tank of the pre-wash zone.The liquid in the pre-wash tank is sprayed onto the items to be washed via a pump system belonging to the pre-wash zone's washing system and the pre-wash nozzles of the pre-wash zone, in order to remove coarse dirt from the items to be washed.

[0015] Regardless of whether the dishwasher is designed as a program-controlled automatic dishwasher or as a conveyor dishwasher, the dishwashers considered herein typically include at least one washing system which has a washing pump that ensures a quasi-constant water circulation rate over the duration of a washing process in the treatment chamber (in the case of program-controlled automatic dishwashers) or in the respective treatment zone (in the case of conveyor dishwashers).

[0016] The dishwashers considered herein also have at least one rinse aid system, wherein a rinse aid liquid is sprayed, or can be sprayed, in the at least one treatment chamber or treatment zone of the dishwashers, particularly as needed and preferably during a rinse cycle. The rinse aid liquid is generally fresh water, which is often heated accordingly in a water heater. A rinse aid chemical is usually added to the fresh water.

[0017] A rinsing system with a rinsing line system and at least one rinsing nozzle system is used to spray the rinsing liquid in the at least one treatment chamber or in the at least one treatment zone.

[0018] With the aim of reducing fresh water consumption during the operation of the dishwasher without negatively affecting the rinsing result, the invention provides that the rinsing system of the dishwasher has at least one backflow preventer associated with the rinsing line system, which is designed to allow the flow of at least one section of the rinsing line system in only one direction.

[0019] The technical effect that can be achieved by providing a corresponding backflow preventer in the rinse aid system is explained below: In particular, when the rinse aid liquid is sprayed intermittently in the at least one treatment chamber or treatment zone during operation of the dishwasher according to the invention, as is the case, for example, with dishwashers designed as automatic programs, the backflow preventer arranged in the rinse aid system prevents the rinse aid system from emptying, at least partially, during so-called pause times, i.e., when no rinse aid liquid is sprayed in the at least one treatment chamber or treatment zone of the dishwasher, in a particularly easy-to-implement yet effective manner.

[0020] The phenomenon of at least partial emptying of the rinse aid system occurs particularly in rinse aid systems that—as is typical—have multiple nozzle systems arranged at different levels within the at least one treatment chamber or treatment zone of the dishwasher. With such dishwashers, there is a risk that during the aforementioned pause periods, when no rinse aid liquid is being sprayed in the at least one treatment chamber or treatment zone, a section of the rinse aid system, in particular, through which a rinse aid nozzle system is supplied with rinse aid liquid as needed and which is located in an upper area of ​​the at least one treatment chamber or treatment zone, will empty itself by gravity.

[0021] If, subsequently, rinsing fluid is to be sprayed via the rinsing system in the at least one treatment chamber or treatment zone, the rinsing nozzle system located at an upper level of the at least one treatment chamber or treatment zone will only be supplied with rinsing fluid with a time delay due to the at least partial emptying of the section of the rinsing line system, while the nozzle systems of the rinsing system located further down, whose corresponding sections of the rinsing line system are not emptied, will be supplied with rinsing fluid at an earlier time.

[0022] In other words, without a backflow preventer, the rinse aid will be sprayed unevenly, at least initially. This is usually compensated for by extending the duration of the rinse phase, i.e., the time during which rinse aid is sprayed via the rinse aid nozzle system, in order to achieve the desired rinsing result.

[0023] In the conventional approach, where the rinsing phase is extended accordingly, there is an overtreatment of the items to be rinsed in certain areas, namely an overtreatment of those areas of the items that are exposed to rinse fluid by the lower rinse nozzle system of the rinse system.

[0024] By installing / integrating a suitable backflow preventer in the rinse system, sections of the rinse system are prevented from emptying during breaks or periods of inactivity. This effectively prevents uneven distribution of rinse fluid to the items being washed, even at the start of the rinse cycle.

[0025] This in turn means that an extension of the rinsing phase is not necessary, so that ultimately rinsing fluid and thus resources, especially fresh water, energy and chemicals, can be saved.

[0026] According to implementations of the dishwasher according to the invention, it is thus provided that the at least one backflow preventer is arranged and in particular integrated upstream of a rinse line section of the rinse line system in the rinse line system, wherein this rinse line section is a line section of the rinse line system from which, outside the rinse phase, i.e. in standby phases, rinse liquid would drain by gravity and thus the line section would at least partially empty itself if no backflow preventer were provided.

[0027] In particular, the at least one backflow preventer is arranged and integrated in the rinse piping system in such a way that even outside the rinse phase, i.e. during rest phases, a section of the rinse piping system which - viewed in the direction of flow through the rinse piping system - lies downstream of the backflow preventer, remains at least partially or partially and preferably completely filled with rinse fluid.

[0028] According to preferred applications of the present invention, the rinsing system comprises a first and a second rinsing nozzle system, each with at least one spray nozzle, wherein rinsing fluid is supplied or can be supplied to the spray nozzles of the first and second rinsing nozzle systems, particularly as required, via the rinsing line system of the rinsing system.

[0029] In this arrangement, preferably the at least one spray nozzle of the first rinse nozzle system is located in a first plane and the at least one spray nozzle of the second rinse nozzle system is located in a second plane that is vertically spaced from the first plane and is higher with respect to the first plane.

[0030] Particularly in such applications, it is advantageous for the rinse line system to have a first rinse line section assigned to the first rinse nozzle system, through which rinse fluid can be supplied to the at least one spray nozzle of the first rinse nozzle system, especially as needed. Conversely, the rinse line system has a second rinse line section assigned to the second rinse nozzle system, through which rinse fluid can be supplied to the at least one spray nozzle of the second rinse nozzle system, especially as needed.

[0031] Preferably, the rinsing system also has a third rinsing section, through which rinsing fluid can be supplied to both the first rinsing section and the second rinsing section, particularly as required.

[0032] It is advisable that at least one backflow preventer be arranged and, in particular, integrated in the second rinse line section.

[0033] Alternatively or additionally, at least one backflow preventer can be arranged and, in particular, integrated in the first and / or third rinse line section.

[0034] Preferably, the at least one backflow preventer is arranged and, in particular, integrated in the rinse line system in such a way that even outside the rinse phase, i.e., during a rest phase, the second rinse line section remains at least partially or partially, and preferably completely, filled with rinse fluid.

[0035] According to conceivable realizations, particularly of the last-mentioned embodiments, it is provided that the rinse piping system has a connection area, in particular designed as a T- or Y-piece, via which the first and second rinse piping sections are flow-wise connected to the third rinse piping section.

[0036] It is advantageous that at least one backflow preventer is located in the second rinse line section and, in particular, is directly adjacent to the connection area and is integrated.

[0037] Alternatively or additionally, at least one backflow preventer can be arranged and, in particular, integrated in the third rinse line section and especially immediately adjacent to the connection area.

[0038] According to various embodiments of the dishwasher according to the invention, a section of the rinse aid system, which – viewed in the direction of flow through the rinse aid system – is located upstream of the backflow preventer, is connected or connectable to a rinse aid supply. The rinse aid supply can include a rinse aid pump and preferably a water heater ("boiler").

[0039] In particular for cleaning the rinse piping system, it is provided that the at least one backflow preventer can be deactivated, especially manually, in such a way that, in the deactivated state of the backflow preventer, the flow from the at least one section of the rinse piping system and preferably the flow from the entire rinse piping system is allowed in both directions.

[0040] Various designs are suitable for backflow preventers. In particular, it is advantageous for the backflow preventer to have at least one check valve and / or non-return valve, especially a ball valve or KFR valve.

[0041] The invention is described in more detail below with reference to the accompanying drawings.

[0042] It shows: FIG. 1 a hydraulic diagram of a dishwasher designed as a program-controlled automatic dishwasher according to an exemplary embodiment of the present invention.

[0043] In FIG. 1 Figure 1 shows a hydraulic diagram of an exemplary embodiment of the dishwasher 1 according to the invention. It should be noted that – although the exemplary embodiment of the dishwasher 1 according to the invention is shown in Figure 1 – FIG. 1 in the form of a program machine - the invention is not limited to dishwashers of this type.

[0044] Rather, the invention relates in particular to dishwashers 1 which are designed as transport dishwashers.

[0045] The exemplary embodiment of the dishwasher 1, designed as a program-controlled automatic dishwasher, has a program control device 100 for controlling at least one cleaning program and a door (in FIG. 1 (not shown) or a hood (also in FIG. 1 (not shown) lockable treatment chamber 2 in a machine housing for receiving items to be cleaned (in FIG. 1 (not shown) items such as dishes, cutlery, pots, pans and trays.

[0046] Below treatment chamber 2 is a wash tank 11 for collecting sprayed liquid from treatment chamber 2. A wash pump 12 is provided for pumping wash liquid from the wash tank 11 through a wash liquid piping system 13 to wash nozzles 14.1, 14.2, which are directed in treatment chamber 2 towards the area of ​​the items to be cleaned and spray the wash liquid onto them. The sprayed wash liquid falls back into the wash tank 11 by gravity.

[0047] The wash tank 11, the wash pump 12, the wash fluid piping system 13, and the wash nozzles 14.1 and 14.2, together with the treatment chamber 2, form a wash fluid circuit. The wash fluid piping system 13 connects the pressure side of the wash pump 12 to the corresponding wash nozzles 14.1 and 14.2.

[0048] Furthermore, a rinse system is provided for pumping rinse fluid by means of a rinse pump 7 through a rinse fluid line system 3 to rinse nozzles 4.1, 4.2, which are directed towards the area of ​​the items to be cleaned in the treatment chamber 2. The sprayed rinse fluid falls by gravity from the treatment chamber 2 into the wash tank 11. The rinse fluid line system 3 connects the pressure side of the rinse pump 7 to the rinse nozzles 4.1, 4.2.

[0049] Preferably, a plurality of wash nozzles 14.2 are provided on at least one upper wash arm, a plurality of wash nozzles 14.1 on at least one lower wash arm, a plurality of rinse nozzles 4.2 on at least one upper rinse arm and a plurality of rinse nozzles 4.1 on at least one lower rinse arm.

[0050] Before rinse liquid is sprayed during a rinse cycle, a quantity of wash liquid corresponding to the rinse liquid is pumped out of the wash tank 11 by means of a drain pump 19, the suction side of which is connected via a drain to a sump of the wash tank 11.

[0051] If the wash tank 11 is empty before the first start of the dishwasher 1, which is designed as a program-controlled automatic dishwasher, it must first be filled with fresh water via a fresh water line or by means of the rinse aid system and its rinse aid pump 7 with fresh water or another rinse aid or wash fluid. The rinse aid can be fresh water, treated fresh water, or fresh water with rinse aid.

[0052] The washing fluid contains cleaner, which is added to the liquid contained in the washing tank 11 by a cleaner dosing device (in FIG. 1 (not shown) is preferably dosed automatically.

[0053] The program control unit 100 controls the wash pump 12, the rinse pump 7, the drain pump 19 and a detergent solution pump (in FIG. 1 (not shown) depending on the cleaning program selected by an operator at the program control unit 100. At least one cleaning program is provided; preferably, several selectable cleaning programs are provided.

[0054] At the in FIG. 1 In the schematically represented exemplary embodiments of the dishwasher 1 according to the invention, the rinse aid pump 7 is connected with its suction side to an outlet of a water heater 8 ("boiler").

[0055] The water heater 8 ("boiler") also has an inlet connected to a fresh water supply line 16, through which either fresh water or fresh water with added rinse aid is supplied to the water heater 8. In the water heater 8, the liquid supplied via the inlet (pure fresh water or fresh water with added rinse aid) is heated according to a specified process sequence. The rinse aid liquid heated in the water heater 8 can be supplied, for example, during a fresh water rinse phase, via the rinse aid line system 3 to the rinse aid nozzles 4.1, 4.2 by the rinse aid pump 7, which is connected with its suction side to the outlet of the water heater 8. The rinse aid nozzles 4.1, 4.2 are arranged in the treatment chamber 2 of the dishwasher 1 to spray the rinse aid liquid, heated by the water heater 8, onto the items being washed in the treatment chamber 2.

[0056] Of course, it is also conceivable that pure fresh water is supplied to the water heater 8 via the inlet and the fresh water supply line 16, to which rinse aid is added after heating in the water heater 8.

[0057] Although in FIG. 1 Not shown, the exemplary embodiment of the dishwasher 1 according to the invention can also be equipped with a fresh water tank without heating, in addition to or as an alternative to the water heater 8. This fresh water tank can preferably have an inlet connected to a fresh water supply line 16, through which clean fresh water or fresh water with added rinse aid is supplied to the fresh water tank.

[0058] Of course, it is also conceivable to install a dosing device for adding rinse aid downstream of the outlet of the fresh water tank.

[0059] At the in FIG. 1 In the schematically illustrated embodiment of the dishwasher 1 according to the invention, the water heater 8 (and, if present, also the fresh water tank) is connected to a backflow preventer 18 via the at least one fresh water supply line 16. The backflow preventer 18 serves to prevent fresh water from being drawn back into the fresh water supply line 16 from the suction side of the rinse pump 7 or from a (further) rinse pump associated with the fresh water tank (not shown in the drawing).

[0060] Although also in FIG. 1 Not shown, the backflow preventer 18 can have an outlet which is connected to a water softening unit via a fresh water supply line 16. The water softening unit can, on the one hand, have a salt container connected to the fresh water supply line 16, and on the other hand, have first and second water softeners arranged in parallel to each other. The two water softeners arranged in parallel can be connected to the outlet of the backflow preventer via a suitable fresh water supply system and the fresh water supply line 16.

[0061] The water softeners of the water softening device can be operated alternately by appropriately controlling valves in order to soften the fresh water supplied to the water heater 8 via the fresh water supply lines and the fresh water supplied (if present) to the fresh water tank via the fresh water supply line 16.

[0062] The water flow within the in FIG. 1 The schematic representation of dishwasher 1 is as follows: Fresh water enters the water heater 8 via a fill valve Y1 and the backflow preventer 18. If necessary, the fresh water is heated there by a heater E1. The liquid level in the water heater 8 is detected by a pressure sensor B3. The fresh water, if heated in the water heater 8, is pumped into the treatment chamber 2 of the dishwasher 1 via the rinse pump 7 and the rinse nozzles 4.1, 4.2.

[0063] The fresh water sprayed in the treatment chamber 2 collects in the wash tank 11. Preferably a heater E2 is provided in the wash tank 11 to keep the liquid collected in the wash tank 11 at temperature.

[0064] The liquid level of the wash tank 11 can be detected via a pressure sensor B4.

[0065] After a wash cycle, some of the liquid collected in the wash tank 11 (washing liquid) is pumped out of the dishwasher 1 into a drain by the drain pump 19. This pumped-out washing liquid is replaced by fresh water or liquid from the water heater 8.

[0066] At the end of each wash cycle, the in FIG. 1 In the schematically shown dishwasher 1, the washing solution on the items being washed is rinsed off with fresh water during the "rinsing" process step. The dishwasher 1 typically has corresponding spray arms serving as a nozzle system, which are often rotating spray arms with rinse nozzles 4.1, 4.2, with the spray arms arranged above and below the items being washed in the treatment chamber 2.

[0067] The flow from the rinse pump 7 to the upper and lower rinse arms is split in a T- or Y-piece 6, which is positioned below the upper rinse arm. The rinse pump 7, the T- or Y-piece 6, and the two rinse arms are connected by water lines 3.1 and 3.2 in the form of hoses and / or pipes.

[0068] Due to the lower position of the T-piece 6 compared to the upper rinse arm, the rinse fluid, which during the rinse phase is located in the pipe section 3.2 between the T- or Y-piece 6 and the upper rinse arm, flows back through the T- or Y-piece 6 into the water heater 8 or into the pipe 3.1 of the lower rinse arm after each rinse, so that the pipe 3.2 to the upper rinse arm empties at least partially.

[0069] In contrast, line 3.1 to the lower rinse arm remains almost full after each rinse cycle.

[0070] This means that during the next rinse cycle, line 3.2 to the upper rinse arm must first be filled before water / rinse fluid is sprayed onto the items being washed from its rinse nozzles 4.2. Meanwhile, at the lower rinse arm, water or rinse fluid comes out of the rinse nozzles 4.1 right at the start of the rinse cycle.

[0071] Due to the short duration of the rinse cycle, lasting only a few seconds, less rinse fluid is sprayed onto the items from the upper rinse arm than from the lower rinse arm. The less water used for the rinse, the more significant this difference becomes.

[0072] In order to further reduce the amount of fresh water during a rinsing cycle, and at the same time to ensure that rinsing fluid comes out of the upper and lower rinsing arms in a similar manner, a backflow preventer 5 is provided according to the invention, which prevents the line 3.2 between the T- or Y-piece 6 and the upper rinsing arm from emptying after each rinsing cycle.

[0073] In a hood-type dishwasher, approximately 120 ml (up to 10% of the total wash volume, depending on the program) of fresh water can be retained.

[0074] With an undercounter washing machine, the amount would be approximately 50 ml (up to 6% of the total washing volume, depending on the respective program) using the present invention.

[0075] Specifically, the aforementioned backflow preventer 5 is integrated in the rinse line 3.2 between the T- or Y-piece 6 and the upper rinse arm immediately after the T- or Y-piece 6, which is permeable from the T- or Y-piece 6 to the upper rinse arm, but blocks the water flow in the opposite direction.

[0076] This ensures that the rinse fluid remains in the corresponding pipe section 3.2 to the upper rinse arm after the rinse cycle and that pipe section 3.2 does not have to be refilled with each rinse cycle.

[0077] The invention is not limited to the embodiment shown in the drawing, but results from a combination of all the features disclosed herein. Bezugszeichen

[0078] 1 Dishwasher 2 Treatment chamber 3 Rinse rinse system 3.1 First rinse section 3.2 Second rinse section 3.3 Third rinse section 4.1 First (lower) rinse nozzles 4.2 Second (upper) rinse nozzles 5 Backflow preventer 6 Connection area / T / Y fitting 7 Rinse pump 8 Water heater 11 Wash tank 12 Wash pump 13 Wash fluid system 14.1 First (lower) wash nozzles 14.2 Second (upper) wash nozzles 16 Fresh water supply 18 Backflow preventer (fresh water supply) 19 Drain pump 100 Program control unit 100 B3 Pressure sensor B4 Pressure sensor E1 Heater E1 E2 Heater E1 Y1 Filling valve Y1

Claims

1. Dishwasher (1), in particular commercial dishwasher (1), which is preferably designed as a program-controlled automatic dishwasher and in particular in the form of a rack-type or hood-type dishwasher, wherein the dishwasher (1) has at least one treatment chamber (2) or treatment zone in which, in particular as required and preferably during a rinse cycle, a rinse liquid is sprayed or can be sprayed, wherein the dishwasher (1) for this purpose has a rinse system with a rinse line system (3) and with at least one rinse nozzle system with rinse nozzles (4.1, 4.2), characterized by the fact that the rinsing system has at least one backflow preventer (5) associated with the rinsing pipe system (3), which is designed to allow the flow of at least one section of the rinsing pipe system (3) in only one direction.

2. Dishwasher (1) according to claim 1, wherein the at least one backflow preventer (5) is arranged and in particular integrated upstream of a rinse aid line section (3.2) of the rinse aid line system (3) in the rinse aid line system (3), wherein the rinse aid line section (3.2) is a line section of the rinse aid line system (3) from which rinse aid liquid would drain by gravity outside the rinse phase and thus the line section (3.2) would at least partially empty itself if no backflow preventer (5) were provided.

3. Dishwasher (1) according to claim 1 or 2, wherein the at least one backflow preventer (5) is arranged and in particular integrated in the rinse aid system (3) such that even outside the rinse aid phase a section (3.2) of the rinse aid system (3), which - viewed in the direction of flow through the rinse aid system (3) - is located downstream of the backflow preventer (5), remains at least partially or partially and preferably completely filled with rinse aid liquid.

4. Dishwasher (1) according to one of claims 1 to 3, wherein the rinse aid system has a first and a second rinse aid nozzle system, each with at least one rinse aid nozzle (4.1, 4.2), wherein rinse aid liquid is supplied or can be supplied to the rinse aid nozzles (4.1, 4.2) of the first and second rinse aid nozzle systems via the rinse aid line system (3) of the rinse aid system, particularly as required.

5. Dishwasher (1) according to claim 4, wherein the at least one rinse nozzle (4.1) of the first rinse nozzle system is located in a first plane and the at least one rinse nozzle (4.2) of the second rinse nozzle system is located in a second plane vertically spaced from the first plane and higher with respect to the first plane.

6. Dishwasher (1) according to claim 4 or 5, wherein the rinse aid line system (3) has a first rinse aid line section (3.1) associated with the first rinse aid nozzle system, through which rinse aid liquid can be supplied to the at least one rinse aid nozzle (4.1) of the first rinse aid nozzle system, in particular as required, and a second rinse aid line section (3.2) associated with the second rinse aid nozzle system, through which rinse aid liquid can be supplied to the at least one rinse aid nozzle (4.2) of the second rinse aid nozzle system, in particular as required, and wherein the rinse aid line system (3) further has a third rinse aid line section (3.3), through which rinse aid liquid can be supplied to both the first rinse aid line section and the second rinse aid line section, in particular as required.

7. Dishwasher (1) according to claim 6, wherein the at least one backflow preventer (5) is arranged and in particular integrated in the second rinse line section (3.2); and / or wherein the at least one backflow preventer (5) is arranged and in particular integrated in the first rinse line section (3.1); and / or wherein the at least one backflow preventer (5) is arranged and in particular integrated in the third rinse line section (3.3).

8. Dishwasher (1) according to claim 6 or 7, wherein the at least one backflow preventer (5) is arranged and in particular integrated in the rinse aid line system (3) such that even outside the rinse aid phase the second rinse aid line section (3.2) remains at least partially or partially and preferably completely filled with rinse aid liquid.

9. Dishwasher (1) according to one of claims 6 to 8, wherein the rinse aid line system (3) has a connection area, in particular designed as a T- or Y-piece (6), via which the first and second rinse aid line sections (3.1, 3.2) are flow-wise connected to the third rinse aid line section (3.3), wherein the at least one backflow preventer (5) is arranged and in particular integrated in the second rinse aid line section (3.2) and in particular directly adjacent to the connection area (6); and / or wherein the at least one backflow preventer (5) is arranged and in particular integrated in the third rinse aid line section (3.3) and in particular directly adjacent to the connection area (6).

10. Dishwasher (1) according to one of claims 1 to 9, wherein a section (3.3) of the rinse aid system (3), which - viewed in the direction of flow through the rinse aid system (3) - is located upstream of the at least one backflow preventer (5), is flowably connected or connectable to a rinse aid supply.

11. Dishwasher (1) according to claim 10, wherein the rinse aid supply comprises a rinse aid pump (7) and preferably a water heater (8).

12. Dishwasher (1) according to one of claims 1 to 11, wherein the at least one backflow preventer (5) is deactivated in such a way, in particular manually, that in the deactivated state of the backflow preventer (5) the flow from the at least one section of the rinse aid system (3) and preferably the flow from the entire rinse aid system (3) is allowed in both directions.

13. Dishwasher (1) according to one of claims 1 to 12, wherein the at least one backflow preventer (5) comprises at least one check valve and / or non-return valve, in particular a ball valve or KFR valve.

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