WO2016155803A1

WO2016155803A1 - Dishwasher with filter self-cleaning mode

Info

Publication number: WO2016155803A1
Application number: PCT/EP2015/057083
Authority: WO
Inventors: Guvenc Nayman Numanoglu; Mehmet Ozan TRAS
Original assignee: Arcelik Anonim Sirketi
Priority date: 2015-03-31
Filing date: 2015-03-31
Publication date: 2016-10-06

Abstract

The present invention relates to a dishwasher (1) comprising a tub (2), a sump (3) which has a drain (3a), a filter unit (4), a hydraulic unit (5), a water softening unit (6) which has an outlet (7) for outputting softened water or regeneration water and a control unit. The dishwasher (1) of the present invention comprises a hose (8) whose upstream end (9) is connected to the outlet (7) of the softening unit (6), and downstream end (10) immediately opens into the sump (3). According to the present invention, the control unit has a filter self-cleaning mode in which the control unit selectively causes the softening unit (6) to output via the hose (8) softened water or regeneration water so as to backwash the filter unit (4) and remove the dirt to the drain (3a) and causes the hydraulic unit (5) to drain the sump (3) without circulating the fluid.

Description

DISHWASHER WITH FILTER SELF-CLEANING MODE

The present invention relates to a dishwasher in particular a domestic dishwasher. The present invention more particularly relates to the filter unit of the dishwasher.

Domestic dishwashers are commonly known in the art. During the washing process, the rotating spray arms sprinkle the articles on the racks with pressurized washing/rinsing fluid. The pressurized fluid removes the dirt, marks or stains from the articles and drains down together with the dissolved dirt into the sump in the bottom of the tub. To prevent circulation of the dirt through the hydraulic unit, i.e., the circulation pump and the spray arms, the dishwasher is generally provided with a filter unit that is arranged between the tub and the sump. The filter unit generally comprises a funnel-shaped fine filter surface which covers the sump. The fine filter surface has an aperture for receiving a releasable filter assembly which has a coarse filter and a micro filter that are concentrically arranged.

A problem with the filter unit is that the washing performance of the dishwasher decreases if the user fails to remove the dirt from the filter unit. Therefore, the filter unit must be regularly cleaned by the user. In general, the proper functioning of the hydraulic unit and the heating unit depends on the filtration performance of the filter unit. For instance, when the coarse dirt heavily covers the fine filter surface during the washing process to the extent that it gets gradually clogged, then the amount of fluid which is drained through the fine filter surface into the sump gradually decreases, and concurrently the amount of fluid which flows down into the filter assembly increases, and, in turn, the amount of fluid which is sucked by the circulation pump through the micro filter increases. In such instances, there is a risk that the micro filter gets clogged through the suction effect of the circulation pump. In the event of clogging, the dirt which is trapped in the micro filter is disintegrated by the suction effect, and subsequently infiltrated into the circulation pump. Thus, the turbidity of the fluid increases and the washing performance decreases. Also in the event of clogging, the amount of fluid which reaches the circulation pump decreases, and an auto-protective mechanism usually shuts the heating unit off due to the reduced circulation of the fluid. To prevent the filter unit from clogging, the user must regularly examine the filter unit and clean it, when necessary. The coarse dirt that is accumulated on the fine filter surface is easily noticeable and therefore the user usually removes such coarse dirt. In contrast thereto, the dirt inside the micro filter can only be seen upon closer inspection, and requires particularly the removal of the coarse filter. It is generally known that users do not regularly examine the micro filter, and usually mistakenly consider that the dishwasher has a deficiency.

An objective of the present invention is to provide a dishwasher which solve the aforementioned problems of the prior art in a cost-effective way and which enables an improved washing performance even when a user fails to clean the filter unit regularly.

This objective has been achieved by the dishwasher as defined in claim 1. Further achievements have been attained by the subject-matters respectively defined in the dependent claims.

The dishwasher of the present invention comprises a hose which has an upstream end that is fluidly connected to the outlet of the water softening unit and a downstream end that immediately opens into the sump. The control unit has a filter self-cleaning mode. The control unit is adapted, in the filter self-cleaning mode, to selectively cause the water softening unit to output softened water or regeneration water so as to backwash the filter unit via the hose and remove the dirt into the drain, and to cause the hydraulic unit to drain the sump without circulating the fluid.

A major advantageous effect of the present invention is that the dishwasher has been enabled to clean the filter unit thoroughly by initiating a filter self-cleaning mode. Thereby, the washing performance can be prevented from decreasing even when the user fails to clean the filter unit regularly. Another major advantageous effect of the present invention is that the filter unit can be selectively backwashed with softened water or regeneration water. In the latter case, particularly by virtue of the high salt content of the regeneration water, the filter unit can be cleaned more effectively. At the same time, the ion exchange material of the water softening unit can be concurrently regenerated in the filter self-cleaning mode. Thereby, the total operation time of the dishwasher can be shortened and the energy consumption can be reduced. Of course, the filter self-cleaning mode can be alternatively conducted without using the regeneration water, for instance, if there is no need to regenerate the ion exchange material.

In an embodiment, the control unit initiates the filter self-cleaning mode at regular intervals. For instance, the filter self-cleaning mode can be initiated once every washing cycle. In alternative embodiments, the filter unit is cleaned less frequently. This embodiment is particularly advantageous as the need for using a detection unit for monitoring the dirtiness of the filter unit can be omitted. Thereby, the number of parts can be reduced and the production/assembly costs can be saved.

In another alternative embodiment, the dirtiness of the filter unit is monitored by a detection unit. In this embodiment, the dirtiness of the filter unit can be monitored by detecting the optical transmittance or the conductivity of the fluid inside the sump. Alternatively the load on the draining pump can be detected. In this embodiment, the filter self-cleaning mode is initiated if it is concluded that the filter unit is dirty based on the monitoring result. The conclusion may be particularly based on the comparison of the detected value with a threshold value. This embodiment is particularly advantageous as the dishwasher can be operated more energy efficiently, i.e., the filter-self-cleaning mode is initiated only when the filter unit is dirty. In alternative versions of this embodiment, the dirtiness of the filter is monitored at regular intervals or continually during the washing process. In the first case, the filter self-cleaning mode can be dispensed with at the elapse of the regular interval if it is concluded that the filter unit is not dirty. Thereby, the dishwasher can be operated more energy efficiently. In the second case, the filter self-cleaning mode can be conducted at any time during the washing process whenever it is concluded that the filter unit is dirty. Thereby, the risk of having inferior washing results can be eliminated or reduced as much as possible. In another version of this embodiment, in both of the aforementioned cases, the filter self-cleaning mode is conducted until it can be concluded that the filter unit is sufficiently clean based on a monitoring result. In another version of this embodiment, the user is prompted via the control panel to manually clean the filter unit, if the filter unit cannot be sufficiently cleaned within a predetermined interval.

In another embodiment, the downstream end of the hose opens into the sump in close proximity to the micro filter. This embodiment is particularly advantageous as the dirt on the microfilter can be more effectively backwashed into the drain with a comparatively higher pressure.

In another embodiment, a spray head is disposed into the sump. The spray head jets the pressurized fluid received through the hose towards the micro filter. In alternative versions of this embodiment, the spray head has static or rotating nozzles. This embodiment is particularly advantageous as the dirt on the microfilter can be even more effectively backwashed by the fluid jets.

According to the present invention, the length of the hose and/or the bends in the hose has been kept as small as possible in order to reduce the frictional losses in the flow of the fluid. Thereby, the pressure drop in the fluid which impinges on the micro filter can be reduced as much as possible. In another embodiment, the hose is at least partly installed within the tub instead of being entirely installed on the underside of the tub wherein a variety of component parts such as the hydraulic unit, the heating unit, and the electrical units are present. This embodiment is particularly advantageous as the hose can be prevented from following a winding course, and becoming unnecessarily long. In addition, the hose can be prevented from receiving damages through contacting the heating unit or any other units.

In another embodiment, the hose is installed such that it bends less than 180 degrees along its entire length. This embodiment is particularly advantageous as the pressure drop in the fluid due to the bend in the hose can be further reduced, and the micro filter can be backwashed more effectively. Thereby, also the risk that the hose becomes kinked or knotted can be eliminated or reduced as much as possible.

In another embodiment, the hose is installed such that it extends substantially straightly between its upstream end and its downstream end. This embodiment is particularly advantageous as the pressure drop due to the length of the hose can be further reduced, and the micro filter can be backwashed more effectively.

In another embodiment, the hose is flexible. This embodiment is particularly advantageous as the hose can slightly swell when it is pressurized by the fluid, and thus the pressure drop in the fluid can be comparatively reduced. Alternatively a rigid hose can be used.

In another embodiment, the hose is partly or entirely covered by a durable enclosure. This embodiment is particularly advantageous as the hose can be protected against damage.

Additional advantageous effects of the dishwasher according to the present invention will become more apparent with the detailed description of the embodiments with reference to the accompanying drawing in which:

Figure 1 – is a schematic partial view of the underside of a dishwasher according to an embodiment of the present invention.

The reference signs appearing on the drawing relate to the following technical features.

Dishwasher
Tub
Sump

3a. Drain
4. Filter unit
5. Hydraulic unit
6. Softening unit
7. Outlet
8. Hose
9. Upstream end
10. Downstream end
11. Fine filter
12. Aperture
13. Filter assembly
14. Coarse filter
15. Micro filter
16. Spray head
17. Nozzle
18. Detection unit
19. Enclosure

The dishwasher (1) comprises a tub (2) for receiving the articles (not shown) to be cleaned, two extendable article racks (not shown) for holding the articles to be cleaned, two rotating spray arms (not shown) for sprinkling the articles inside the racks with pressurized washing/rinsing fluid respectively, a sump (3) which is arranged into the bottom of the tub (2) for collecting the fluid, wherein the sump (3) has a drain (3a), a filter unit (4) which is arranged upstream of the sump (3) for filtering the fluid, a hydraulic unit (5) for circulating or draining the fluid, wherein the hydraulic circuit (5) has a circulation pump (5a) and a draining pump (not shown), wherein the circulation pump (5a) is connected to the sump (3) and to the rotating spray arms by a manifold (5b), and wherein the draining pump is connected to the drain (3a) of the sump (3) and to a drain hose (not shown) which is connectable to a waste water line (not shown); a water softening unit (6) which comprises an inlet (not shown) for receiving fresh water from a tank (not shown) which has a metering unit (not shown) which is connectable to a fresh water line (not shown) and an outlet (7) for outputting softened water or regeneration water; a control unit (not shown) for controlling the hydraulic unit (5), the water softening unit (6), and the metering unit (Fig. 1).

The dishwasher (1) of the present invention comprises a hose (8) which has an upstream end (9) that is fluidly connected to the outlet (7) of the water softening unit (7) and a downstream end (10) that immediately opens into the sump (3). The control unit has a filter self-cleaning mode. In the filter self-cleaning mode, the control unit selectively causes the water softening unit (6) to output via the hose (8) softened water or regeneration water so as to backwash the filter unit (4) and remove the dirt into the drain (3a), and causes the hydraulic unit (5) to drain the sump (5) without circulating the fluid.

In an embodiment, the control unit initiates the filter self-cleaning mode at regular intervals.

In an alternative embodiment, the dishwasher (1) further comprises a detection unit (18) for monitoring the dirtiness of the filter unit (4). In this embodiment, the control unit initiates the filter self-cleaning mode in accordance with the monitoring result.

In another embodiment, the filter unit (4) comprises a fine filter surface (11) which has an aperture (12) for holding a releasable filter assembly (13). The fine filter surface (11) covers the sump (3). The filter assembly (13) comprises a coarse filter (14) and a micro filter (15). In this embodiment, the downstream end (10) of the hose (8) opens into the sump (3) in close proximity to the micro filter (15) so as to backwash the micro filter (15) and remove the dirt into the drain (3a).

In another embodiment, the dishwasher (1) further comprises a spray head (16) which is disposed into the sump (3). The spray head (16) comprises nozzles (17) which are directed onto the micro filter (15). In this embodiment, the downstream end (10) of the hose (8) is fluidly connected to the spray head (16).

In another embodiment, that spray head (16) is rotatably disposed around the micro filter (15).

In another embodiment, the hose (8) is at least partly installed within the tub (2).

In another embodiment, the hose (8) is installed such that it bends less than 180 degrees along its entire length.

In another embodiment, the hose (8) extends straightly between its upstream end (9) and its downstream end (10).

In another embodiment, the hose (8) is made from a flexible material.

In another embodiment, the dishwasher (1) further comprises a protective enclosure (19) which covers at least the section of the hose (8) which is installed within the tub (2).

In another embodiment, the protective enclosure (19) covers the entire hose (8).

A major advantageous effect of the present invention is that the dishwasher (1) has a filter self-cleaning mode for cleaning the filter unit (4). Thereby, the washing performance can be prevented from decreasing. Another major advantageous effect of the present invention is that the filter unit (4) can be selectively backwashed with softened water or regeneration water. In the latter case, particularly by virtue of the high salt content of the regeneration water, the filter unit (4) can be cleaned more effectively, and at the same time, the ion exchange material of the water softening unit (6) can be concurrently regenerated. Thereby, the total operation time of the dishwasher (1) can be shortened and the energy consumption can be reduced. Of course, the filter self-cleaning mode can be alternatively conducted without using the regeneration water, for instance, if there is no need to regenerate the ion exchange material. Other additional advantageous effects of the present invention can be taken from the aforementioned embodiments.

Claims

A dishwasher (1) comprising a tub (2), a sump (3) which is arranged into the bottom of the tub (2) for collecting the fluid, wherein the sump (3) has a drain (3a), a filter unit (4) which is arranged upstream of the sump (3) for filtering the fluid, a hydraulic unit (5) for circulating or draining the fluid, a water softening unit (6) which has an outlet (7) for outputting softened water or regeneration water, a control unit for controlling the hydraulic unit (5) and the water softening unit (6), characterized in that a hose (8) which has an upstream end (9) that is fluidly connected to the outlet (7) of the water softening unit (6) and a downstream end (10) that immediately opens into the sump (3), wherein the control unit has a filter self-cleaning mode, wherein the control unit is adapted, in the filter self-cleaning mode, to selectively cause the water softening unit (6) to output via the hose (8) softened water or regeneration water so as to backwash the filter unit (4) and remove the dirt into the drain (3a) and to cause the hydraulic unit (5) to drain the sump (3) without circulating the fluid.
The dishwasher (1) according to claim 1, characterized in that the control unit is adapted to initiate the filter self-cleaning mode at regular intervals.
The dishwasher (1) according to claim 1, characterized in that a detection unit (18) for monitoring the dirtiness of the filter unit (4), wherein the control unit is adapted to initiate the filter self-cleaning mode in accordance with the monitoring result.
The dishwasher (1) according to any one of claims 1 to 3, characterized in that the filter unit (4) comprising a fine filter surface (11) which has an aperture (12) for holding a releasable filter assembly (13), wherein the fine filter surface (11) covers the sump (3), wherein the filter assembly (13) comprising a coarse filter (14) and a micro filter (15), and wherein the downstream end (10) of the hose (8) opens into the sump (3) in close proximity to the micro filter (15) so as to backwash the micro filter (15) and remove the dirt into the drain (3a).
The dishwasher (1) according to claim 4, characterized in that a spray head (16) which is disposed into the sump (3), wherein the spray head (16) has nozzles (17) which are directed onto the micro filter (15), and wherein downstream end (10) of the hose (8) is fluidly connected to the spray head (16).
The dishwasher (1) according to claim 5, characterized in that that spray head is rotatably disposed around the micro filter (15).
The dishwasher (1) according to claim 1, characterized in that the hose (8) is at least partly installed within the tub (2).
The dishwasher (1) according to claim 7, characterized in that the hose (8) is installed such that it bends less than 180 degrees along its entire length.
The dishwasher (1) according to any one of claim 8, characterized in that the hose (8) extends straightly between its upstream end (9) and its downstream end (10).
The dishwasher (1) according to any one of claims 7 to 9, characterized in that the hose (8) is made from a flexible material.
The dishwasher (1) according to claim 1, characterized in that a protective enclosure (19) which covers at least the section of the hose (8) which is installed within the tub (2).