AU2013406467A1

AU2013406467A1 - Dishwasher and method for collecting washing liquid in a dishwasher

Info

Publication number: AU2013406467A1
Application number: AU2013406467A
Authority: AU
Inventors: Johan Persson; Johan Spang
Original assignee: Electrolux Appliances AB
Current assignee: Electrolux Appliances AB
Priority date: 2013-11-29
Filing date: 2013-11-29
Publication date: 2016-04-21
Anticipated expiration: 2033-11-29
Also published as: WO2015078513A1; EP3073885A1; AU2013406467B2; PL3073885T3; EP3073885B1

Abstract

A dishwasher (1) and a method (100) for collecting washing liquid in a dishwasher are provided. The dishwasher (1) comprises a washing chamber (2) with a sump (3), a circulation circuit (4), a circulation pump (5), a first spray arrangement (6a), a flow control device (7), a washing liquid storage tank (8) connected to the circulation circuit (4). The flow control device (7) is arrangable to control washing liquid flow to said first spray arrangement (6a) such that washing liquid is arranged to be sprayed into said washing chamber (2) with a first flow rate (12). The circulation pump (5) is arrangable to pump washing liquid with a second flow rate (13), which second flow rate (13) exceeds said first flow rate (12) such that excess washing liquid is arranged to flow from the circulation circuit (4) to the washing liquid storage tank (8).

Description

WO 2015/078513 PCT/EP2013/075089 DISHWASHER AND METHOD FOR COLLECTING WASHING LIQUID IN A DISHWASHER TECHNICAL FIELD 5 Embodiments herein relate to a dishwasher. Embodiments herein further relate to a method for collecting washing liquid in a dishwasher. BACKGROUND Today's dishwashers are expected to perform high quality wash of dishes. Also, 10 environmental concerns require an efficient use of water and energy during a wash session. The requirement of performing high quality wash of dishes and the requirement of efficient use of water and energy during a wash session can be seen as two conflicting requirements. However, the use of a washing liquid storage tank arranged to store washing liquid for subsequent re-use can reduce the use of washing liquid and 15 energy during a wash session while the quality of the washing process is unaffected, or even improved. A washing liquid storage tank can be arranged to store washing liquid for re-use in a later stage of a wash cycle or for re-use in a subsequent wash cycle. The use of a washing liquid storage tank is described in the document EP 2583614 A2. However, a washing liquid storage tank, and the arrangement needed for the purpose of 20 filling and emptying such a tank may add a considerable amount of production cost to a dishwasher. The filling and emptying of such a tank require components as well as control functions. In the light of the above, there is a need for a dishwasher capable of collecting washing liquid and being simple and cost efficient to manufacture. 25 An object of the present invention is to provide a dishwasher capable of collecting washing liquid, and where the dishwasher is simple and cost effective to manufacture. SUMMARY Embodiments herein aim to provide dishwasher eliminating or at least reducing the 30 problems and/or drawbacks associated with prior art solutions.

WO 2015/078513 PCT/EP2013/075089 2 According to an embodiment, this is provided by a dishwasher comprising; a washing chamber with a sump, a circulation circuit comprising said sump, a circulation pump with an inlet and a first outlet, arranged to pump washing liquid in said circulation circuit, a first spray arrangement arranged to spray washing liquid into the washing chamber, a 5 flow control device arranged to selectively control washing liquid flow to said first spray arrangement, a washing liquid storage tank, a first conduit, said washing liquid storage tank being connected to said circulation circuit via said first conduit, a flow control valve arranged in the first conduit, having at least an open state and a closed state, and an actuator arranged to control the flow control valve between the open state and the 10 closed state, wherein said flow control device is arrangable to control liquid flow to said first spray arrangement such that washing liquid is arranged to be sprayed into said washing chamber with a first flow rate, in that said circulation pump is arrangable to pump washing liquid with a second flow rate, which second flow rate exceeds said first flow rate, and in that said valve is arrangable to be controlled to the open state by said 15 actuator such that excess washing liquid is arranged to flow from the circulation circuit to the washing liquid storage tank via said first conduit. By the circulation pump being arrangable to pump washing liquid with a second flow rate which exceeds the first flow rate, and by the valve being arrangable to be controlled to 20 the open state by the actuator, the excess washing liquid is arranged to flow from the circulation circuit to the washing liquid storage tank via said first conduit. Since the excess washing liquid is arranged to flow to the washing liquid storage tank, the washing liquid storage tank may be at least partly filled due to the difference in flow rate between the first flow rate and the second flow rate when the flow control device is arranged to 25 control liquid flow to said first spray arrangement. Further, since the excess washing liquid is arranged to flow to the washing liquid storage tank while washing liquid is arranged to be sprayed into said washing chamber with a first flow rate, a duration of a washing cycle may be shorter than if the collecting of washing liquid and the spraying into the washing chamber were performed at different periods during the washing cycle. 30 Hereby a dishwasher is provided which is capable of collecting washing liquid, and where the dishwasher is simple and cost effective to manufacture. As a result, the above mentioned object is achieved.

WO 2015/078513 PCT/EP2013/075089 3 According to some embodiments said excess liquid is arranged to flow from said circulation circuit to said washing liquid storage tank with a third flow rate, and in that said third flow rate together with said first flow rate corresponds to said second flow rate. 5 When excess liquid is arranged to flow from said circulation circuit to said washing liquid storage tank with a third flow rate, and said third flow rate together with said first flow rate corresponds to said second flow rate, the third flow rate may be controlled as a function of the first flow rate and/or the second flow rate. The first, second and third flow 10 rates may be at least partly controlled e.g. by a selected geometry of the circulation circuit, the first conduit and/or the washing liquid storage tank. The flow rates may also be at least partly controlled by e.g. a selected circulation pump speed, and/or a geometry and opening/closing time of the flow control valve. Due to this flexibility, the flow of excess liquid from the circulation circuit to the washing liquid storage tank may be 15 easily controlled in any desired manner. According to some embodiments said circulation circuit comprises a second spray arrangement arranged in said washing chamber, and said first spray arrangement is arranged above said second spray arrangement. When said circulation circuit comprises 20 a first spray arrangement arranged above a second spray arrangement, the first arrangement may be arranged to spray washing liquid in an upper part of the washing chamber, and the second arrangement may be arranged to spray washing liquid in a lower part of the washing chamber. 25 According to some embodiments said flow control device is arrangable to control washing liquid flow to said first spray arrangement only. When the flow control device is arranged to control washing liquid flow to the first spray arrangement only, the vertical level of a water column in the circulation circuit up to the first spray arrangement and/or a flow resistance related to the spraying of washing liquid through the first spray 30 arrangement into said washing chamber may be used to control the excess washing liquid to flow up into the washing liquid storage tank. According to some embodiments said first flow rate corresponds to a dish treatment flow rate, in which dish arranged in said washing chamber is treated by said washing liquid.

WO 2015/078513 PCT/EP2013/075089 4 When said first flow rate corresponds to a dish treatment flow rate, in which dishes arranged in said washing chamber is treated in order to become clean by said washing liquid, the excess washing liquid is arranged to flow from the circulation circuit to the 5 washing liquid storage tank when the washing liquid is arranged to be sprayed into said washing chamber with a dish treatment flow rate via the first spray arrangement. The first flow rate may be selected such that the dishes are treated by some of the washing liquid from the circulation pump, while some of the washing liquid is arranged to flow up to the washing liquid storage tank. Hereby washing liquid may be collected in the 10 washing liquid storage tank during a rinse cycle without an increased washing cycle time caused by the collection of washing liquid. According to some embodiments the difference in flow rate between said first flow rate and said second flow rate causes a pressure in at least a part of the circulation circuit, 15 where said pressure exceeds gravity-related-pressure, such that said excess washing liquid is arranged to be pushed up into said washing liquid storage tank via said first conduit due to said pressure when said circulation pump is arranged to pump washing liquid in said circulation circuit. The difference in flow rate between said first flow rate and said second flow rate causes a pressure in at least a part of the circulation circuit, 20 causing excess washing liquid to be pushed up into said washing liquid storage tank due to said pressure. Hereby the pressure in the circulation system may be used to at least partly fill the washing liquid storage tank. According to some embodiments said excess washing liquid is arranged to flow from 25 said circulation circuit to said washing liquid storage tank via said first conduit up to a vertical level in said washing liquid storage tank which is arranged above a vertical level of said first spray arrangement in said dishwasher. Since said excess washing liquid is arranged to flow from said circulation circuit to said washing liquid storage tank via said first conduit up to a vertical level in said washing liquid storage tank which is arranged 30 above a vertical level of said first spray arrangement in said dishwasher, a potential energy of the washing liquid may be large. Hereby the washing liquid collected in the washing liquid storage tank may flow from the tank to the first and/or second spray arrangement with large force e.g. in a later rinse procedure.

WO 2015/078513 PCT/EP2013/075089 5 According to some embodiments said circulation pump comprises a second outlet connected to said washing liquid storage tank via the first conduit, and in that said excess washing liquid is arranged to flow from said circulation pump to said washing liquid storage tank via said second outlet. As excess washing liquid is arranged to flow 5 from the circulation pump to the washing liquid storage tank via said second outlet, a dishwasher is provided which is capable of collecting washing liquid, and which dishwasher is simple and cost efficient to manufacture. Also, due to the second outlet, a length of the first conduit may be reduced. 10 According to some embodiments washing liquid collected in the washing liquid storage tank during a first washing cycle is arranged to be used in a subsequent washing cycle. When washing liquid collected in the washing liquid storage tank during a first washing cycle is arranged to be used in a subsequent washing cycle, a dishwasher is provided where the use of clean water and energy can be reduced. 15 Embodiments herein aim to provide a method for collecting and temporarily storing washing liquid in a dishwasher, eliminating or at least reducing the problems and/or drawbacks associated with prior art dishwashers. 20 According to an embodiment, this is provided by a method for collecting washing liquid in a dishwasher where the dishwasher comprises; a washing chamber with a sump, a circulation circuit comprising said sump, a circulation pump with an inlet and a first outlet, arranged to pump washing liquid in said circulation circuit, a first spray arrangement arranged to spray washing liquid into the washing chamber, a flow control device 25 arranged to selectively control washing liquid flow to said first spray arrangement, a washing liquid storage tank, a first conduit, said washing liquid storage tank being connected to said circulation circuit via said first conduit, a flow control valve arranged in the first conduit, having at least an open state and a closed state, and an actuator arranged to control the flow control valve between the open state and the closed state. 30 The method for collecting washing liquid in the dishwasher comprises; controlling liquid flow to said first spray arrangement such that washing liquid is arranged to be sprayed into said washing chamber with a first flow rate, using said flow control device, pumping washing liquid with a second flow rate, which second flow rate exceeds said first flow WO 2015/078513 PCT/EP2013/075089 6 rate, using said circulation pump, and controlling said flow control valve to an open state such that excess washing liquid is arranged to flow from the circulation circuit to the washing liquid storage tank via said first conduit, using said actuator. Hereby washing liquid may be collected in the washing liquid storage tank in a cost efficient manner. The 5 collected washing liquid may be used in a subsequent washing cycle. Thus, hereby is provided a method for collecting washing liquid in a dishwasher, eliminating or at least reducing the problems and/or drawbacks associated with prior art solutions. 10 Further features of, and advantages with, the embodiments herein will become apparent when studying the appended claims and the following detailed description. Those skilled in the art will realize that different features of the embodiments herein may be combined to create embodiments other than those described in the following, without departing 15 from the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The various aspects of embodiments herein, including its particular features and advantages, will be readily understood from the following detailed description and the 20 accompanying drawings, in which: Fig. 1 illustrates dishwasher according to some embodiments. Fig. 2 illustrates a method according to some embodiments. 25 DETAILED DESCRIPTION Embodiments herein will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. However, this application should not be construed as being limited to the embodiments set forth herein. 30 Disclosed features of example embodiments may be combined as readily understood by one of ordinary skill in the art to which this application belongs. Like numbers refer to like elements throughout the description.

WO 2015/078513 PCT/EP2013/075089 7 In order to keep the description concise, well-known functions or constructions have not been described in detail. In Fig. 1 a dishwasher 1 is illustrated. The dishwasher 1 comprises a washing chamber 5 2 with a sump 3 and a circulation circuit 4. The circulation circuit 4 comprises the sump 3, a circulation pump 5 with an inlet 5a and a first outlet 5b. The circulation pump 5 is arrangable to pump washing liquid in the circulation circuit 4. The circulation circuit 4 also comprises a first spray arrangement 6a 10 which is arranged to spray washing liquid into the washing chamber 2, and a flow control device 7 arrangable to selectively control washing liquid flow to the first spray arrangement 6a. According to some embodiments, the circulation circuit 4 further comprises a second spray arrangement 6b as shown in Fig. 1. In the Fig. 1 embodiment, the first spray arrangement 6a is arranged above the second spray arrangement 6b. The 15 first spray arrangement 6a may be arranged to distribute washing liquid to dish 15 arranged in an upper part and/or lower part of the washing chamber 2, and the second spray arrangement 6b may be arranged to mainly distribute washing liquid to dish 15 arranged in a lower part of the washing chamber 2. The one or more spray arrangements 6 may comprise spray arms provided with nozzles, and the spray arms 20 may be arranged to rotate by a reaction force of washing liquid being sprayed out of the nozzles into the washing chamber 3. The circulation circuit 4 may comprise one or more conduits or tubes, arranged to allow the washing liquid to flow e.g. between the sump 3, the circulation pump 5, the flow control device 7 and the one or more spray arrangements 6. The circulation circuit 4 is further arranged to be connected to water 25 mains and a drain, e.g. via connections (not shown) in the sump 3. The washing liquid may comprise water, a mixture of water, detergent and/or softener. When the washing liquid has been sprayed into the washing chamber 2, onto the dishes 15 placed in the washing chamber 2, the washing liquid is arranged to be collected in the 30 sump 3. The sump 3 may be arranged in a lower part of the washing chamber 2. As illustrated in Fig. 1, the circulation pump 5 is arranged to pump washing liquid from the sump 3 to the one or more spray arrangements 6 via the first outlet 5b of the circulation pump 5 and the flow control device 7. The flow control device 7 may be of any WO 2015/078513 PCT/EP2013/075089 8 suitable type, as known in the art, such as a disc-type flow control device. The circulation pump 5 may be of radial flow type, such as a centrifugal pump, or axial flow type or half axial flow type. The circulation pump 5 is driven by an electric motor (not shown). 5 The dishwasher 1 further comprises a washing liquid storage tank 8 arranged at a side of and/or above of the washing chamber 2 and a first conduit 9. The washing liquid storage tank 8 is connected to the circulation circuit 4 via the first conduit 9. The first conduit 9 may be connected to any suitable part or portion of the circulation circuit 4, and may be connected to any portion of the washing liquid storage tank 8. According to 10 some embodiments, the first conduit 9 is connected to a conduit of the circulation circuit 4 e.g. via a T-coupling. According to some embodiments, the first conduit 9 is connected to the flow control device 7. In the Fig. 1 illustrated embodiment, the circulation pump 5 comprises a second outlet 5c coupled to the first conduit 9. According to the embodiment illustrated in Fig. 1, the first conduit 9 is connected to a lower portion of the 15 washing liquid storage tank 8. The first conduit 9 and/or conduits arranged in the circulation circuit 4 may comprise one or more flexible hoses. The washing liquid storage tank 8 may comprise a venting passage or a venting valve (not shown) in an upper region of the washing liquid storage tank 8 in order to admit passage of air while filling or emptying the washing liquid storage tank 8. 20 A flow control valve 10 is arranged in the first conduit 9. The flow control valve 10 has at least an open state and a closed state. In the open state, washing liquid may flow in the conduit 9 between the circulation circuit 4 and the washing liquid storage tank 8. In the closed state, washing liquid is prevented from flowing between the washing liquid 25 storage tank 8 and the circulation circuit 4. In the closed state, washing liquid collected in the washing liquid storage tank 8 may be retained in the washing liquid storage tank 8. The flow control valve 10 may be of any suitable type, as known in the art, such as a ball-type, globe-type or butterfly-type valve. 30 An actuator 11 is connected to the flow control valve 10, and the actuator 11 is arranged to control the flow control valve 10 between the open state and the closed state. The actuator 11 may be e.g. a bi-metal actuator, a solenoid, an electric motor or an electrothermic actuator such as a wax motor. An electrothermic actuator may be relatively cost efficient, and may allow a flow area in the flow control valve 10 to be WO 2015/078513 PCT/EP2013/075089 9 relatively large. The dishwasher 1 may further comprise a control unit, which control unit is arranged to control the actuator 11 and/or an electric motor which is driving the circulation pump 5. 5 The flow control device 7 may be arranged to the control washing liquid flow to the first spray arrangement 6a such that washing liquid is arranged to be sprayed into said washing chamber 2. A speed and/or effect of the circulation pump 5 may affect the flow rate. The flow rate may also be affected by a geometry of conduits in the circulation circuit and/or a geometry of the spray arrangements 6 or parts thereof, such as spray 10 arms and nozzles. Washing liquid in the circulation circuit 4 may be controlled to flow from the circulation circuit 4 to the washing liquid storage tank 8 during one or more periods of a washing cycle, such that the in the washing liquid storage tank 8 collected washing liquid may be 15 used later. Washing liquid in the circulation circuit 4 may be controlled to flow from the circulation circuit 4 to the washing liquid storage tank 8 e.g. under two different time periods during a washing cycle, a first period and a second period. The first and second periods may be selected to occur e.g. during one or more rinse periods during the washing cycle. 20 During such a first period, e.g. selected to occur during a cold rinse period, the circulation pump 5 may be arranged to pump washing liquid in the circulation circuit 4, and the flow control device 7 may be arranged to the control washing liquid flow to the first spray arrangement 6a. The actuator 11 may be arranged to control the flow control 25 valve 10 to be in an open state. The circulation pump 5 may be arranged to pump washing liquid in the circulation circuit 4 with a selected flow rate. Since the flow control device 7 may control washing liquid flow only to the first spray arrangement 6a while the circulation pump 5 is running, washing liquid may be pumped 30 from the sump 3 both towards the first spray arrangement 6a and the washing liquid storage tank 8. The flow control device 7 may thus be arranged to close a connection between the first circulation pump 5 and the lower spray arrangement 6b in embodiments comprising such a lower spray arrangement 6b. Thereby, a flow resistance in the conduit arranged between the first outlet 5b of the circulation pump 5 and the WO 2015/078513 PCT/EP2013/075089 10 spray arrangements 6a can be increased as compared to when running the circulation pump 5 with an open connection between the first outlet 5b of the circulation pump 5 and the lower spray arrangement 6b. Closing the connection between the first outlet 5b and the lower spray arrangement 6b may also serve to speed up the process of filling the 5 washing liquid storage tank 8. As a result, filling of the washing liquid storage tank 8 with washing liquid can be performed with a reduced rotational speed of the circulation pump 9. Hereby washing liquid may be pumped up to a first vertical level 18 in both the washing 10 liquid storage tank 8 and the circulation circuit 4. The first vertical level 18 may be an equilibrium vertical level which depends e.g. on the circulation pump speed and the dimensions and geometry of the circulation circuit 4, the washing liquid storage tank 8 and the first conduit 9. The first vertical level 18 may be arranged at substantially the same vertical level as the first spray arrangement 6a, or below the vertical level of the 15 first spray arrangement 6a. When the equilibrium vertical level is reached, no flow at all, or only a small amount of flow, occurs in the circulation circuit 4. Since the flow control valve 10 between the washing liquid storage tank 8 and the circulation circuit 4 is open, the first vertical level 18 may be substantially the same in 20 both the circulation circuit 4 and the washing liquid storage tank 8. In the circulation circuit 4, the washing liquid may reach the first vertical level 18 in e.g. a conduit of the circulation circuit 4 which is arranged between the flow control device 7 and the first spray arrangement 6a. 25 The actuator 11 may then be arranged to close the flow control valve 10. The actuator 11 may be arranged to close the flow control valve 10 based on time, i.e. an amount of time after the opening of the flow control valve 10. Alternatively, the actuator 11 may be arranged to close the flow control valve 10 based on sensor data, e.g. relating to a detected pressure, weight and/or volume. 30 When the flow control valve 10 is in the closed state again, the washing liquid storage tank 8 is partly filled with washing liquid. If the first period occurs under a rinse period during a washing cycle, the washing liquid collected in the washing liquid storage tank 8 is relatively clean and free from dirt and debris. According to an exemplifying WO 2015/078513 PCT/EP2013/075089 11 embodiment, one or a few litres of washing liquid may be collected in the washing liquid storage tank 8 during this first period. An additional amount of washing liquid may be collected in the washing liquid storage 5 tank 8 during a second period of the washing cycle. Such a second period may be selected to occur during a rinse period of the washing cycle, such as during a hot rinse period. During such a second period, the circulation pump 5 may be arranged to pump washing 10 liquid in the circulation circuit 4, and the flow control device 7 may be arranged to control washing liquid flow to the first spray arrangement 6a only. The circulation pump 5 may be arranged to pump washing liquid in the circulation circuit 4 with a second flow rate 13. The second flow rate 13 may be higher than the flow rate selected during the first period and may be lower than a flow rate from the circulation pump 5 during other periods of the 15 washing cycle. The actuator 11 may be arranged to control the flow control valve 10 to be in an open state. During this second step, washing liquid may be arranged to be sprayed into the washing chamber 2 with a first flow rate 12 via the first spray arrangement 6a. The first sprayed 20 flow rate 12 may depend e.g. on the flow rate from the circulation pump 5 and the geometry and/or dimension of the spray arrangement 6a, such as the number of spray nozzles and the size of the nozzles. A flow resistance of nozzles of the upper spray arrangement 6a may be used to be able to fill the washing liquid storage tank 8 with washing liquid to a level which may exceed the vertical level of the upper spray 25 arrangement 6a. During at least a part of the second period, the second flow rate 13 exceeds the first flow rate 12. Since the second flow rate 13 from the circulation pump 5 exceeds the first flow rate 12 sprayed through the first spray arrangement 6a into the washing chamber 2, 30 excess washing liquid is arranged to flow from the circulation circuit 4 to the washing liquid storage tank 8 via said first conduit 9. In other words, since only some of the washing liquid, which is pumped from the sump 3 via the circulation pump 5, may flow through the first spray arrangement 6a, the remaining water from the circulation pump 5 is instead pressed up into the washing liquid storage tank 8 via the first conduit 9 and the WO 2015/078513 PCT/EP2013/075089 12 open flow control valve 10. Hereby the amount of washing liquid collected in the washing liquid storage tank 8 may reach a second vertical level 19, which second vertical level 19 is arranged above the first vertical level 18. The second vertical level 19 may be arranged above a vertical level of the spray arrangement 6a. The second vertical level 5 19 may be arranged at a substantial distance above the vertical level of the spray arrangement 6a, e.g. near an upper part of the washing liquid storage tank 8. When the second vertical level 19 is reached, a major part of, or the entire, washing liquid storage tank 8 may be filled. 10 The actuator 11 may then be arranged to close the flow control valve 10. The actuator 11 may be arranged to close the flow control valve 10 based on time, i.e. an amount of time after the opening of the flow control valve. Alternatively, the actuator 11 may be arranged to close the flow control valve 10 based on sensor data, e.g. relating to a detected pressure, weight and/or volume. 15 Thus, washing liquid may be arranged to flow up to the first vertical level 18 during the first period of a washing cycle, and then to the second vertical level 19 during the second period of a washing cycle. 20 According to some embodiments, washing liquid is collected in the washing liquid storage tank 8 during the second period described above only. The second period may then occur e.g. during a rinse period of the washing cycle. The washing liquid collected in the washing liquid storage tank 8 during a first washing cycle may be arranged to be used in a subsequent washing cycle. During other periods of the washing cycle, in which 25 no filling of the washing liquid storage tank 8 occurs, the first 12 and second 13 flow rate may be substantially the same. According to some embodiments, washing liquid in the washing liquid storage tank 8 is arranged to be evacuated from the washing liquid storage tank 8 to the spray 30 arrangement 6 and/or the sump 3 via the circulation pump 5 when the flow control valve 10 is in the open state. According to some embodiments, washing liquid in the washing liquid storage tank 8 is arranged to be evacuated from the washing liquid storage tank 8 by a force of gravity, and according to some embodiments the circulation pump 5 may be used. The washing liquid in the washing liquid storage tank 8 can hereby be re-used in WO 2015/078513 PCT/EP2013/075089 13 an easy manner. The washing liquid in the washing liquid storage tank 8 can be re-used in a later stage of a wash cycle or re-used in a subsequent wash cycle. For example, relatively clean washing liquid collected during a washing cycle may be used e.g. for a pre-rinse of dish in a subsequent washing cycle. 5 In Fig. 2 a method 100 for collecting washing liquid in a dishwasher is illustrated. The dishwasher may comprise; a washing chamber with a sump, a circulation circuit comprising said sump, a circulation pump with an inlet and a first outlet, arranged to pump washing liquid in said circulation circuit, a first spray arrangement arranged to 10 spray washing liquid into the washing chamber, a flow control device arranged to selectively control washing liquid flow to said first spray arrangement, a washing liquid storage tank, a first conduit, said washing liquid storage tank being connected to said circulation circuit via said first conduit, a flow control valve arranged in the first conduit, having at least an open state and a closed state, and an actuator arranged to control the 15 flow control valve between the open state and the closed state The method 100 comprises; - controlling 101 liquid flow to said first spray arrangement such that washing liquid is arranged to be sprayed into said washing chamber with a first flow rate 102, 20 using said flow control device, - pumping 102 washing liquid with a second flow rate, which second flow rate exceeds said first flow rate, using the said circulation pump, and - controlling 103 said valve to an open state such that excess washing liquid is arranged to flow from the circulation circuit to the washing liquid storage tank via 25 first conduit, using said actuator. Although the aspects has been described with reference to example embodiments, many different alterations, modifications and the like will become apparent for those skilled in the art. Therefore, it is to be understood that the foregoing is illustrative of 30 various example embodiments and the scope of the appended claims is not to be limited to the specific embodiments disclosed and that modifications to the disclosed embodiments, combinations of features of disclosed embodiments as well as other embodiments are intended to be included within the scope of the appended claims.

WO 2015/078513 PCT/EP2013/075089 14 As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof. 5

Claims

1. A dishwasher (1) comprising; - a washing chamber (2) with a sump (3), 5 - a circulation circuit (4) comprising said sump (3), a circulation pump (5) with an inlet (5a) and a first outlet (5b), arranged to pump washing liquid in said circulation circuit (4), a first spray arrangement (6a) arranged to spray washing liquid into the washing chamber (2), a flow control device (7) arranged to selectively control washing liquid flow to said first spray 10 arrangement (6a), - a washing liquid storage tank (8), - a first conduit (9), said washing liquid storage tank (8) being connected to said circulation circuit (4) via said first conduit (9), - a flow control valve (10) arranged in the first conduit (9), having at least 15 an open state and a closed state, and - an actuator (11) arranged to control the flow control valve (10) between the open state and the closed state, characterized in that said flow control device (7) is arrangable to control washing liquid flow to said first spray arrangement (6a) such that washing liquid 20 is arranged to be sprayed into said washing chamber (2) with a first flow rate (12), in that said circulation pump (5) is arrangable to pump washing liquid with a second flow rate (13), which second flow rate (13) exceeds said first flow rate (12), and in that said flow control valve (10) is arrangable to be controlled to the open state by said actuator (11) such that excess washing liquid is arranged to 25 flow from the circulation circuit (4) to the washing liquid storage tank (8) via said first conduit (9).

2. The dishwasher (1) according to claim 1, characterized in that said excess liquid is arranged to flow from said circulation circuit (4) to said washing liquid storage 30 tank (8) with a third flow rate, and in that said third flow rate together with said first flow rate (12) corresponds to said second flow rate (13).

3. The dishwasher (1) according to claim 1, characterized in that said circulation circuit (4) comprises a second spray arrangement (6b) arranged in said washing WO 2015/078513 PCT/EP2013/075089 16 chamber (2), and in that said first spray arrangement (6a) is arranged above said second spray arrangement (6b).

4. The dishwasher (1) according to claim 1 or 2, characterized in that said flow 5 control device (7) is arrangable to control washing liquid flow to said first spray arrangement (6a) only.

5. The dishwasher (1) according to any one of the preceding claims, characterized in that said first flow rate (12) corresponds to a dish treatment flow rate, in which 10 dish (15) arranged in said washing chamber (2) is treated by said washing liquid.

6. The dishwasher (1) according to any one of the preceding claims, characterized in that the difference in flow rate between said first flow rate (12) and said second flow rate (13) causes a pressure in at least a part of the circulation circuit (4), 15 where said pressure exceeds gravity-related-pressure, such that said excess washing liquid is arranged to be pushed up into said washing liquid storage tank (8) via said first conduit (9) due to said pressure when said circulation pump (5) is arranged to pump washing liquid in said circulation circuit (4). 20

7. The dishwasher (1) according to any one of the preceding claims, characterized in that said excess washing liquid is arranged to flow from said circulation circuit (4) to said washing liquid storage tank (8) via said first conduit (9) up to a vertical level in said washing liquid storage tank (8) which is arranged above a vertical level of said first spray arrangement (6a) in said dishwasher (1). 25

8. The dishwasher (1) according to any one of the preceding claims, characterized in that said circulation pump (5) comprises a second outlet (5c) connected to said washing liquid storage tank (8) via the first conduit (9), and in that said excess washing liquid is arranged to flow from said circulation pump (5) to said washing 30 liquid storage tank (8) via said second outlet (5c).

9. The dishwasher (1) according to any one of the preceding claims, characterized in that washing liquid collected in the washing liquid storage tank (8) during a first washing cycle is arranged to be used in a subsequent washing cycle. WO 2015/078513 PCT/EP2013/075089 17

10. A method (100) for collecting washing liquid in a dishwasher (1) where the dishwasher (1) comprises; a washing chamber (2) with a sump (3), a circulation circuit (4) comprising said sump (3), a circulation pump (5) with an inlet (5a) and 5 a first outlet (5b), arranged to pump washing liquid in said circulation circuit (4), a first spray arrangement (6a) arranged to spray washing liquid into the washing chamber (2), a flow control device (7) arranged to selectively control washing liquid flow to said first spray arrangement (6a), a washing liquid storage tank (8), a first conduit (9), said washing liquid storage tank (8) being connected to said 10 circulation circuit (4) via said first conduit (9), a flow control valve (10) arranged in the first conduit (9), having at least an open state and a closed state, and an actuator (11) arranged to control the flow control valve (10) between the open state and the closed state, characterized in that the method (100) comprises; - controlling (101) liquid flow to said first spray arrangement (6a) such that 15 washing liquid is arranged to be sprayed into said washing chamber (2) with a first flow rate, using said flow control device (7), - pumping (102) washing liquid with a second flow rate, which second flow rate exceeds said first flow rate, using said circulation pump (5), and - controlling (103) said flow control valve (10) to an open state such that 20 excess washing liquid is arranged to flow from the circulation circuit (4) to the washing liquid storage tank (8) via said first conduit (9), using said actuator (11).