WO2017088934A1

WO2017088934A1 - Dishwasher and method for drying washed items in a dishwasher

Info

Publication number: WO2017088934A1
Application number: PCT/EP2015/077971
Authority: WO
Inventors: Stefan Jonsson; Anna DELIN
Original assignee: Electrolux Appliances Aktiebolag
Priority date: 2015-11-27
Filing date: 2015-11-27
Publication date: 2017-06-01

Abstract

A dishwasher (1) is provided comprising a wash tub (3) for housing items to be washed. The wash tub (3) comprises a wash tub bottom (5) at a bottom of the wash tub (3). The dishwasher (1) further comprises a drying arrangement (7) for drying washed items, wherein the drying arrangement (7) comprises one or more apertures (9.1, 9.2). The drying arrangement (7) is arranged to direct a liquid onto the wash tub bottom (5), via the one or more apertures (9.1, 9.2), to create a liquid surface at the wash tub bottom (5) adapted to change a state of a fluid within the wash tub (3) from gaseous state to liquid state. The present disclosure also relates to a method for drying washed items in a dishwasher (1).

Description

DISHWASHER AND METHOD FOR DRYING WASHED ITEMS IN A DISHWASHER TECHNICAL FIELD

The present invention relates to a dishwasher and a method for drying washed items in a dishwasher.

BACKGROUND

Today's dishwashers are expected to perform high quality wash of dishware, and environmental concerns require an efficient use of energy during operation. Also, it is an advantage if washed items are dry after a washing phase. In the last phase of a wash cycle, water is sprayed into the wash tub of the dishwasher in order to rinse the washed items. After stopping, the remaining water will form drops and pools on the washed items and at the racks. Modern dishwashers often use heat during a drying phase to dry the washed items, for example by having heaters within the dishwasher and/or by blowing warm air inside the dishwasher. In addition, in the last phase of a wash cycle, warm water may be sprayed in to the dishwasher in order to heat the washed items. During heating, the water will slowly evaporate and the size of the drops will gradually be reduced, and air within the wash tub of the dishwasher will become humid. One problem is that the use of heat during a drying phase requires a large amount of energy.

Some dishwashers are provided with a system automatically opening a front lid of the dishwasher slightly during the drying phase. It's an efficient way of drying the dish load since the humid air is vented out via a slot formed between the lid and the tub. However this also means that the kitchen worktop becomes exposed for humid hot air and hence there is a risk that it becomes harmed. A further problem with such a system is that it requires additional components and control systems which add costs to the dishwasher. With a closed system the drying phase occurs within the tub, without any humid air vented out. With a closed drying system there are a few ways to reduce the humidity. Some dishwashers condensate the humidity on a surface, such as at the walls inside the wash tub and this works if the dish load is heated to a fairly high temperature before or during the drying phase. High temperature means higher energy consumption and therefore not an optimal solution. The document FR2641690 A1 relates to a dishwasher comprising a sprinkler pipe arranged to apply cold water onto a back wall of a dishwasher to condensate moist from air within the dishwasher. The dishwasher described in FR2641690 A1 is associated with some problems. One problem is the risk of wetting washed items during such a procedure.

SUMMARY

An object of the present invention is to provide an improved dishwasher that eliminates or at least reduces the problems and/or drawbacks associated with the prior art solutions.

According to an aspect of the invention, the object is achieved by a dishwasher comprising a wash tub for housing items to be washed, wherein the wash tub comprises a wash tub bottom at a bottom of the wash tub, wherein the dishwasher comprises a drying arrangement for drying washed items, wherein the drying arrangement comprises one or more apertures, wherein the drying arrangement is arranged to direct a liquid, having a lower temperature than a temperature of an environment within the wash tub, onto the wash tub bottom, via the one or more apertures, to create a liquid surface at the wash tub bottom adapted to change a state of a fluid within the wash tub from gaseous state to liquid state.

The liquid surface is adapted to change a state of a fluid within the wash tub from gaseous state to liquid state by having a lower temperature than the environment within the wash tub. Thus, the liquid surface will cause the fluid within the washtub to condensate. As a result, less heat can be supplied prior to and/or during a drying phase of the dishwasher, while maintaining, or even improving a drying effect. Further, fluid within the washtub is removed without the need for an automatic opening a front lid of the dishwasher during the drying phase. As a result, a kitchen worktop will not become exposed for humid hot air and hence there is no risk that it becomes harmed.

In addition, a dishwasher is provided which can be manufactured in a cost efficient manner since it requires few additional components. Further, since the drying arrangement is arranged to direct a liquid onto the wash tub bottom, the risk for wetting washed items during a drying procedure is avoided.

Thus, an improved dishwasher is provided that eliminates or at least reduces the problems and/or drawbacks associated with the prior art solutions. Thus, the above mentioned object is achieved

Optionally, the one or more apertures are arranged at a peripheral edge of the wash tub bottom. As a result, the liquid surface will be created at a large proportion of the wash tub bottom. Thereby, the drying performance will be improved and even less energy may be required during a drying phase of the dishwasher.

Optionally, the wash tub bottom is inclined essentially towards a centre of the wash tub bottom, and wherein the one or more apertures are arranged to direct the liquid along the peripheral edge of the wash tub bottom. As a result, the liquid will be guided along the peripheral edge and will flow from the peripheral edge towards the centre of the wash tub bottom. Thereby, an even and coherent liquid surface may be created using few apertures. Using few apertures reduces cost and complexity of the drying arrangement. Further, apertures having larger aperture diameters can be used. Thereby, the risk of particles becoming trapped in the apertures will be reduced.

Optionally, the one or more apertures comprise a first aperture and a second aperture, wherein the first aperture and the second aperture are arranged to direct the liquid in essentially opposite directions. Thus, two apertures are arranged to direct the liquid onto the wash tub bottom. The first aperture and the second aperture may be arranged in a common housing, which facilitates wiring of the supply of liquid to the apertures. Since they are arranged to direct the liquid in essentially opposite directions an even and coherent liquid surface is created using a low number of apertures. As a result, cost and complexity of the drying arrangement is further reduced.

Optionally, the drying arrangement comprises a control unit arranged to control a flowrate of the liquid directed onto the wash tub bottom such that the flowrate varies periodically. As a result, less liquid can be used while maintaining the drying effect. Optionally, the drying arrangement comprises a humidity sensor and a control unit, wherein the humidity sensor is arranged to sense humidity within the wash tub, and wherein the control unit is arranged to control a flowrate of the liquid directed onto the wash tub bottom based on the humidity. As a result, the control unit will control the change of the state of the fluid within the wash tub from gaseous state to liquid state in dependence of the humidity within the wash tub. Thereby, less liquid can be used while maintaining the drying effect.

Optionally, the dishwasher comprises a pump and one or more spray arrangements arranged to spray washing liquid into the wash tub to wash the items to be washed, and a flow control arrangement comprising an inlet, a primary outlet, at least one secondary outlet and an interior volume, wherein the inlet is connected to the pump, and wherein the primary outlet is connected to the one or more spray arrangements, and wherein the at least one secondary outlet is connected to the one or more apertures, wherein the flow control arrangement is provided with a constantly open first flow path from the inlet to the primary outlet via the interior volume, and wherein the flow control arrangement further comprises a valve configured to open a second flow path between the inlet and the at least one secondary outlet when a flowrate of liquid within the interior volume is lower than a predetermined flowrate, and configured to close the second flow path when the flowrate exceeds the predetermined flowrate. As a result, a simple arrangement is provided capable of providing the liquid surface at the wash tub bottom. Since the arrangement is simple, it can be provided in a cost efficient manner while maintaining a reliable operation. Optionally, the pump is configured to cause the flowrate to exceed the predetermined flow rate during a washing phase of the dishwasher, and configured to cause the flow rate to be less than the predetermined flow rate during a drying phase of the dishwasher. Thus, when the pump causes the flowrate to exceed the predetermined flow rate during a washing phase, the valve will close the second flow path. As a result, no liquid will be directed onto the wash tub bottom via the one or more apertures. Since the flow control arrangement is provided with a with a constantly open first flow path, washing liquid will flow from the pump to the one or more spray arrangements arranged to spray washing liquid into the wash tub. During the drying phase, when the pump causes the flow rate to be less than the predetermined flow rate, the valve will open the second flow path. As a result, liquid will be directed onto the wash tub bottom via the one or more apertures.

Accordingly, a dishwasher is provided capable of creating the liquid surface at the wash tub bottom, using few components. As a result, cost and complexity is further reduced.

Optionally, the dishwasher comprises a duct connecting the primary outlet of the flow control arrangement and the one or more spray arrangements, wherein the one or more spray arrangements comprises spray nozzles arranged to spray liquid into the wash tub during the washing phase, wherein the flow control arrangement is arranged at a lower position in the dishwasher than a lowermost spray nozzle of the spray nozzles and at a vertical distance therefrom to form a liquid column in the duct preventing a flow of liquid through the primary outlet, when the flow rate is less than the predetermined threshold value. As a result, washing liquid is prevented from reaching the spray nozzles during the drying phase. Accordingly, a dishwasher is provided capable of performing an improved control of liquid and the risk of wetting washed items during the drying phase is further reduced.

Optionally, the dishwasher comprises a pump, a liquid reuse tank and a sump arranged at a centre of the wash tub bottom, wherein the pump is arranged to pump the liquid from the sump to the one or more apertures of the drying arrangement during a time period, and arranged to pump the liquid to the liquid reuse tank, when the time period has elapsed. Accordingly, the pump may be arranged to circulate the liquid from the sump to the one or more apertures and back to the sump via the wash tub bottom. The pump may thus circulate a certain volume of liquid over the wash tub bottom during the time period. As a result, less liquid can be used than would be the case with a continuous supply of liquid. Since the liquid has a lower temperature than a temperature of the environment within a washtub, the certain volume of liquid will gradually be heated, during the time period. However, since the pump is arranged to pump the liquid to the liquid reuse tank, when the time period has elapsed, the liquid may cool down in the liquid reuse tank and may thus be used in a subsequent circulation phase. As a result, even less liquid may be used to dry washed items. A further object of the present invention is to provide an improved method for drying washed items in a dishwasher that eliminates or at least reduces the problems and/or drawbacks associated with the prior art solutions According to a further aspect of the invention, the object is achieved by a method for drying washed items in a dishwasher comprising a wash tub for housing the washed items, wherein the wash tub comprises a wash tub bottom at a bottom of the wash tub, wherein the dishwasher comprises a drying arrangement for drying the washed items, wherein the drying arrangement comprises one or more apertures, wherein the method comprises:

directing a liquid onto the wash tub bottom, having a lower temperature than a temperature of an environment within the wash tub, via the one or more apertures, to create a liquid surface at the wash tub bottom adapted to change a state of a fluid within the wash tub from gaseous state to liquid state.

The liquid surface is adapted to change a state of a fluid within the wash tub from gaseous state to liquid state by having a lower temperature than the environment within the wash tub. Thus, the liquid surface will cause the fluid within the washtub to condensate. As a result, less heat can be supplied prior to and/or during a drying phase of the dishwasher, while maintaining, or even improving a drying effect. Further, fluid within the washtub is removed without the need for an automatic opening a front lid of the dishwasher during the drying phase. As a result, a kitchen worktop will not become exposed for humid hot air and hence there is no risk that it becomes harmed. Further, since the method comprises directing a liquid onto the wash tub bottom, the risk for wetting washed items during a drying procedure is avoided.

Thus, an improved method for drying washed items in a dishwasher is provided that eliminates or at least reduces the problems and/or drawbacks associated with the prior art solutions. Thus, the above mentioned object is achieved

Optionally, the dishwasher comprises a pump, a liquid reuse tank and a sump arranged at a centre of the wash tub bottom, wherein the method further comprises: pumping the liquid from the sump to the one or more apertures of the drying arrangement during a time period, using the pump, and

pumping the liquid to the liquid reuse tank, when the time period has elapsed, using the pump.

Since the method comprises pumping the liquid from the sump to the one or more apertures of the drying arrangement during a time period, the liquid will be circulated from the sump to the one or more apertures and back to the sump via the wash tub bottom. As a result, less liquid can be used than would be the case with a continuous supply of liquid. Since the liquid has a lower temperature than a temperature of the environment within a washtub, the certain volume of liquid will gradually be heated, during the time period. However, since the pump is arranged to pump the liquid to the liquid reuse tank when the time period has elapsed, the liquid may cool down in the liquid reuse tank and may thus be used in a subsequent circulation phase. As a result, less liquid may be used to dry washed items.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description. Those skilled in the art will realize that the different features described may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention, as defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which:

Fig. 1 illustrates a dishwasher,

Fig. 2 illustrates a wash tub of the dishwasher illustrated in Fig. 1 ,

Fig. 3a and Fig. 3b illustrate a flow control arrangement, and

Fig. 4 illustrates a method for drying washed items in a dishwasher. DETAILED DESCRIPTION

Embodiments herein will now be described more fully with reference to the

accompanying drawings, in which example embodiments are shown. Disclosed features of example embodiments may be combined as readily understood by one of ordinary skill in the art. Like numbers refer to like elements throughout.

Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity. Fig. 1 illustrates a dishwasher 1. Fig. 2 illustrates a wash tub 3, of the dishwasher 1 illustrated in Fig. 1. The wash tub 3 comprises a wash tub bottom 5 at a bottom of the wash tub 3. The dishwasher further comprises a drying arrangement 7 for drying washed items, wherein the drying arrangement 7 comprises one or more apertures 9.1 , 9.2. The embodiments illustrated in Fig. 1 comprise two apertures, a first aperture 9.1 , and a second aperture 9.2. The drying arrangement 7 is arranged to direct a liquid, having a lower temperature than a temperature of an environment within the wash tub 3, onto the wash tub bottom 5, via the one or more apertures 9.1 , 9.2, to create a liquid surface at the wash tub bottom 5. The liquid surface is adapted to change a state of a fluid within the wash tub 3 from gaseous state to liquid state by having a lower temperature than the environment within the wash tub 3. The change a state of a fluid within the wash tub 3 from gaseous state to liquid state may also be referred to as a condensation of fluid within the wash tub 3.

To ensure that the liquid surface has a lower temperature than the environment within the wash tub 3, the drying arrangement 7 may further comprise heating arrangements (not shown in Fig. 2) arranged to supply heat to the environment within the wash tub 3 prior to, or during a drying phase of the dishwasher. In addition, the liquid directed onto the wash tub bottom 5 may comprise tap water from a tap water supply. Such tap water usually has a temperature lower than a normal room temperature of approximately 20°C. By using a combination of heating elements and water from a tap water supply, the liquid surface will provide an efficient rate of change of state of a fluid within the wash tub 3 from gaseous state to liquid state. An efficient rate change of state of a fluid within the wash tub 3 from gaseous state to liquid state may also be referred to as an efficient condensation rate. The fluid within the wash tub 3 is, under normal circumstances, humid air, i.e. air comprising a certain amount of water in gaseous state.

According to some embodiments, the drying arrangement 7 is arranged to create the liquid surface at the wash tub bottom 5 by filling the wash tub bottom 5 with liquid such that a stagnant pool of liquid is formed at the wash tub bottom 5.

As an alternative, or in addition, the drying arrangement 7 is arranged to create the liquid surface at the wash tub bottom 5 by, at least during a time period, continuously directing the liquid onto the wash tub bottom 5, via the one or more apertures 9.1 , 9.2, to create flow of liquid flowing over the surface of the wash tub bottom 5.

As illustrated in Fig. 2, the one or more apertures 9.1 , 9.2 are arranged at a peripheral edge 1 1 of the wash tub bottom 5. The wash tub bottom 5 is inclined essentially towards a centre 13 of the wash tub bottom 5, and wherein the one or more apertures 9.1 , 9.2 are arranged to direct the liquid along the peripheral edge 1 1 of the wash tub bottom 5. The drying arrangement 7 comprises a first aperture 9.1 and a second aperture 9.2, wherein the first aperture 9.1 and the second aperture 9.2 are arranged to direct the liquid in essentially opposite directions. Thereby, the liquid will be guided along the peripheral edgel 1 of the wash tub bottom 5 and will flow from the peripheral edge 1 1 towards the centre 13 of the wash tub bottom 5. Thereby, an even and coherent liquid surface can be created using a low number of apertures 9.1 , 9.2. Using a low number of apertures 9.1 , 9.2 reduces cost and complexity of the drying arrangement and reduces the risk of particles becoming trapped in the apertures 9.1 , 9.2 during operation since apertures 9.1 , 9.2 having a larger cross section can be used than would be the case if a higher number of apertures were used.

In addition, as is illustrated in Fig. 2, the first aperture 9.1 and the second aperture 9.2 may be arranged in a common housing which facilitates wiring of the supply of liquid to the respective aperture 9.1 , 9.1. As a result, cost and complexity of the drying arrangement 7 is further reduced.

According to some embodiments, the drying arrangement 7 comprises a control unit 15 arranged to control a flowrate of the liquid directed onto the wash tub bottom 5 such that the flowrate varies periodically. The control unit 15 may be arranged to control the flowrate of the liquid by controlling a pump speed of a pump 21. By varying the flowrate periodically, less liquid can be used while maintaining a proper condensation rate in the wash tub 3. The control unit 15 may be arranged to control a flowrate of the liquid directed onto the wash tub bottom 5 such that a certain flowrate of liquid is directed onto the wash tub bottom 5 during first time periods and no flow of liquid is directed onto the wash tub bottom 5 during second time periods. In such embodiments, after a first time period, the liquid surface has lowered the temperature of the wash tub bottom 5. So, during a second time period, when no flow of liquid is directed onto the wash tub bottom 5, the relatively cold wash tub bottom 5 will also provide a change of state of a fluid within the wash tub 3 from gaseous state to liquid state. In these embodiments, the first time periods may for example have a length of 1-20 minutes and the second time periods may for example have a length of 1 -5 minutes

According to some embodiments, the drying arrangement 7 comprises a humidity sensor 17 and the control unit 15, wherein the humidity sensor 17 is arranged to sense humidity within the wash tub 3, and wherein the control unit 15 is arranged to control a flowrate of the liquid directed onto the wash tub bottom 5 based on the humidity. Thereby, the control unit 15 will control the condensation of fluid within the wash tub 3 in dependence of the humidity within the wash tub 3. As a result, less water and energy may be used during a drying phase of the dishwasher. In addition, the control unit 15 may determine, on the basis of the humidity within the wash tub 3, when to end a drying phase.

According to some embodiments, the control unit 15 is arranged to control a flowrate of the liquid directed onto the wash tub bottom 5 the such that the drying arrangement 7 periodically directs the liquid onto the wash tub bottom 5 with at least one of intervals and durations being based on the humidity of air within the wash tub 5. Thereby, even less water and energy may be used during a drying phase of the dishwasher, while maintaining a proper condensation rate in the wash tub 3. The dishwasher comprising the wash tub 3 illustrated in Fig. 2, further comprises one or more spray arrangements 23 arranged to spray washing liquid into the wash tub 3 to wash the items to be washed, during a washing phase. The dishwasher further comprises a flow control arrangement 31. Fig. 3a and Fig. 3b illustrates the flow control arrangement 31 illustrated in Fig. 2 in greater detail. The flow control arrangement 31 comprises an inlet 35, a primary outlet 37, at least one secondary outlet 39.1 , 39.2 and an interior volume 41 . The inlet 35 is connected to the pump 21 illustrated in Fig. 2. The primary outlet 37 is connected to the one or more spray arrangements 23 illustrated in Fig. 2. The at least one secondary outlet 39.1 , 39.2 is connected to the one or more apertures 9.1 , 9.2, illustrated in Fig. 2. As illustrated in Fig. 3a and Fig. 3b, the flow control arrangement 31 is provided with a constantly open first flow path 42 from the inlet 35 to the primary outlet 37 via the interior volume 41 . The flow control arrangement 31 further comprises a valve 43 configured to open a second flow path 34 between the inlet 35 and the at least one secondary outlet 39.1 , 39.2 when a flowrate of liquid within the interior volume 41 is lower than a predetermined flowrate, and configured to close the second flow path 34 when the flowrate exceeds the predetermined flowrate. The term connected to is intended to encompass a flow connection.

In Fig. 3a, the flow control arrangement 31 is illustrated in a situation in which the flowrate of liquid within the interior volume 41 is lower than a predetermined flowrate. As can be seen, the second flow path 34 between the inlet 35 and the at least one secondary outlet 39.1 , 39.2 is open.

In Fig. 3b, the flow control arrangement 31 is illustrated in a situation in which the flowrate of liquid within the interior volume 41 exceeds the predetermined flowrate. As can be seen, the second flow path 34 between the inlet 35 and the at least one secondary outlet 39.1 , 39.2 is closed.

The valve 43 comprises a valve body 44 displaceably arranged within the interior volume 41 between an open position and a closed position, wherein the second flow path 34 is open in the open position, and wherein the second flow path 34 is closed in the closed position. The valve body 44 is arranged to be displaced towards the open position by a force caused by at least one of gravity and a spring 46 when being subjected to a flow of liquid within the interior volume 41 having a flow rate being lower than the predetermined flow rate. Such open position is illustrated in Fig. 3a.

The valve body 44 is arranged to be displaced towards the closed position when being subjected to a flow of liquid within the interior volume 41 having a flow rate exceeding the predetermined flow rate. Such closed position is illustrated in Fig. 3b. The predetermined flowrate may be determined by choosing cross sectional area of the valve body 44 subjected to the flow of liquid within the interior volume 41 , cross sectional area of the first flow path 42, weight of the valve body 44, strength and direction of force of the spring 46, and hydrodynamic properties of the valve body 44.

The flow control arrangement 31 comprises an elongated element 47 extending into the interior volume 41 , wherein the elongated element 47 comprises the valve 43 and the second flow path 34. Thereby, a simple and reliable flow control arrangement 31 is provided and a low flow resistance in the first flow path 42 is ensured.

The pump 21 , illustrated in Fig. 2, is configured to cause the flowrate to exceed the predetermined flow rate during a washing phase of the dishwasher. As a result, the valve 43 will close the second flow path 34 between the inlet 35 and the at least one secondary outlet 39.1 , 39.2. Since the at least one secondary outlet 39.1 , 39.2 is connected to the one or more apertures 9.1 , 9.2, illustrated in Fig. 2, no liquid will be directed onto the wash tub bottom 5 during the washing phase.

The pump 21 , illustrated in Fig. 2, is further configured to cause the flow rate to be less than the predetermined flow rate during a drying phase of the dishwasher. As a result, the valve 43 will open the second flow path 34 between the inlet 35 and the at least one secondary outlet 39.1 , 39.2. Since the at least one secondary outlet 39.1 , 39.2 is connected to the one or more apertures 9.1 , 9.2, illustrated in Fig. 2, liquid will be directed onto the wash tub bottom 5 during the drying phase.

As illustrated in Fig. 2, the dishwasher comprising the wash tub 3 further comprises a duct 45 connecting the primary outlet 37 of the flow control arrangement 31 , illustrated in Fig. 3a and Fig. 3b, and the one or more spray arrangements 23, illustrated in Fig. 2. The one or more spray arrangements 23 comprises spray nozzles 48 arranged to spray liquid into the wash tub 33 during the washing phase, and the flow control arrangement 31 is arranged at a lower position in the dishwasher than a lowermost spray nozzle 49 of the spray nozzles 48 and at a vertical distance therefrom. Thereby, a liquid column is formed in the duct 45 preventing a flow of liquid through the primary outlet 37, when the flow rate is less than the predetermined threshold value. Thereby, a simple and efficient arrangement is provided in which liquid can be directed to the one or more apertures 9.1 , 9.2 or to the spray nozzles 48 of the one or more spray arrangements 23 simply by controlling the pump speed of the pump 21.

The embodiments illustrated in Fig. 2 further comprises a second spray arrangement 51 arranged at lower position in the dishwasher than a lowermost spray nozzle 49 of the one or more spray arrangements 23. In these embodiments, the dishwasher comprises a flow control valve 53 controllable by the control unit 15 between at least a first position and a second position, where in the first position, a flow path is formed between the pump 21 and the duct 45 as well as a flow path between the pump and a supply duct 55 to the second spray arrangement 51. During a washing phase, the control unit 15 is arranged to control the flow control valve 53 to the first position. During a drying phase, the control unit 15 is arranged to control the flow control valve 53 to the second position. In the second position, the flow path between the pump and a supply duct 55 of the second spray arrangement 51 is closed and the flow path between the pump 21 and the duct 45 is open. Thereby, during the drying phase, no liquid will be supplied to the second spray arrangement 51. As a result, during the drying phase, the drying arrangement 7 will direct a liquid onto the wash tub bottom 5, via the one or more apertures 9.1 , 9.2, to create a liquid surface at the wash tub bottom 5, and the formation of the liquid column in the duct 45 is ensured.

According to some embodiments, the dishwasher comprises a pump 21 , a liquid reuse tank 50 and a sump 52 arranged at a centre 13 of the wash tub bottom 5. The pump 21 may be arranged to pump the liquid from the sump 52 to the one or more apertures 9.1 , 9.2 of the drying arrangement 7 during a time period, and arranged to pump the liquid to the liquid reuse tank 50, when the time period has elapsed. This may be achieved by the flow control valve 53 controlling flow from the pump 21 to the flow control arrangement 31 during the time period, and when the time period has elapsed, control flow from the pump 21 to the liquid reuse tank 50.

The liquid will flow from the one or more apertures 9.1 , 9.2 towards the centre 13 of the wash tub bottom 5, where the sump 52 is arranged. The sump 52 is in flow connection with the pump 21 . The pump 21 may thus circulate liquid from the sump 52 to the one or more apertures 9.1 , 9.2 and back to the sump 52 via the wash tub bottom 5. Accordingly, a certain volume of liquid may be circulated over the wash tub bottom 5 during the time period. As a result, less liquid can be used than would be the case with a continuous supply of liquid. Since the liquid has a lower temperature than a temperature of the environment within a washtub 3, the certain volume of liquid will gradually be heated, during the time period. A length of the a time period may be adapted to a rate of heating of the liquid and may for example be 10-20 minutes. Since the pump 21 is arranged to pump the liquid to the liquid reuse tank 50 when the time period has elapsed, the liquid may cool down in the liquid reuse tank 50 and may thus be used in a subsequent circulation phase. As a result, less liquid may be used to dry washed items.

When the time period has elapsed, the liquid may be replaced with fresh liquid, e.g. fresh tap water from a tap water supply. Thereby, a low temperature of the liquid surface created at the wash tub bottom 5 can be ensured.

Fig. 4 illustrates a method 100 for drying washed items in a dishwasher comprising a wash tub for housing the washed items, wherein the wash tub comprises a wash tub bottom at a bottom of the wash tub, wherein the dishwasher comprises a drying arrangement for drying the washed items, wherein the drying arrangement comprises one or more apertures, wherein the method 100 comprises:

directing 101 a liquid onto the wash tub bottom, having a lower temperature than a temperature of an environment within the wash tub, via the one or more apertures, to create a liquid surface at the wash tub bottom adapted to change a state of a fluid within the wash tub from gaseous state to liquid state.

Optionally, the dishwasher comprises a pump, a liquid reuse tank and a sump arranged at a centre of the wash tub bottom, wherein the method 100 further comprises:

pumping 102 the liquid from the sump to the one or more apertures of the drying arrangement during a time period, using the pump, and

- pumping 103 the liquid to the liquid reuse tank, when the time period has

elapsed, using the pump.

Claims

1. A dishwasher (1 ) comprising a wash tub (3) for housing items to be washed, wherein said wash tub (3) comprises a wash tub bottom (5) at a bottom of said wash tub (3), wherein said dishwasher (1 ) comprises a drying arrangement (7) for drying washed items, wherein said drying arrangement (7) comprises one or more apertures (9.1 , 9.2),

characterized in that said drying arrangement (7) is arranged to direct a liquid, having a lower temperature than a temperature of an environment within said wash tub (3), onto said wash tub bottom (5), via said one or more apertures (9.1 , 9.2), to create a liquid surface at said wash tub bottom (5) adapted to change a state of a fluid within said wash tub (3) from gaseous state to liquid state.

2. The dishwasher (1 ) according to claim 1 , wherein said one or more apertures (9.1 , 9.2) are arranged at a peripheral edge (1 1 ) of said wash tub bottom (5).

3. The dishwasher (1 ) according to claim 2, wherein said wash tub bottom (5) is

inclined essentially towards a centre (13) of said wash tub bottom (5), and wherein said one or more apertures (9.1 , 9.2) are arranged to direct said liquid along said peripheral edge (1 1 ) of said wash tub bottom (5).

4. The dishwasher (1 ) according to claim 3, wherein said one or more apertures (9.1 , 9.2) comprise a first aperture (9.1 ) and a second aperture (9.2), wherein said first aperture (9.1 ) and said second aperture (9.2) are arranged to direct said liquid in essentially opposite directions.

5. The dishwasher (1 ) according to any one of the preceding claims, wherein said

drying arrangement (7) comprises a control unit (15) arranged to control a flowrate of said liquid directed onto said wash tub bottom (5) such that said flowrate varies periodically.

6. The dishwasher (1 ) according to any one of the preceding claims, wherein said

drying arrangement (7) comprises a humidity sensor (17) and a control unit (15), wherein said humidity sensor (17) is arranged to sense humidity within said wash tub (3), and wherein said control unit (15) is arranged to control a flowrate of said liquid directed onto said wash tub bottom (5) based on said humidity.

7. The dishwasher (1 ) according to any one of the preceding claims, comprising a

pump (21 ) and one or more spray arrangements (23) arranged to spray washing liquid into said wash tub (3) to wash said items to be washed, and a flow control arrangement (31 ) comprising an inlet (35), a primary outlet (37), at least one secondary outlet (39.1 , 39.2) and an interior volume (41 ), wherein said inlet (35) is connected to said pump (21 ), and wherein said primary outlet (37) is connected to said one or more spray arrangements (23), and wherein said at least one secondary outlet (39.1 , 39.2) is connected to said one or more apertures (9.1 , 9.2), wherein said flow control arrangement (31 ) is provided with a constantly open first flow path (42) from said inlet (35) to said primary outlet (37) via said interior volume (41 ), and wherein said flow control arrangement (31 ) further comprises a valve (43) configured to open a second flow path (34) between said inlet (35) and said at least one secondary outlet (39.1 , 39.2) when a flowrate of liquid within said interior volume (41 ) is lower than a predetermined flowrate, and configured to close said second flow path (34) when said flowrate exceeds said predetermined flowrate.

8. The dishwasher (1 ) according to claim 7, wherein said pump (21 ) is configured to cause said flowrate to exceed said predetermined flow rate during a washing phase of said dishwasher (1 ), and configured to cause said flow rate to be less than said predetermined flow rate during a drying phase of said dishwasher (1 ).

9. The dishwasher (1 ) according to claim 8, comprising a duct (45) connecting said primary outlet (37) of said flow control arrangement (31 ) and said one or more spray arrangements (23), wherein said one or more spray arrangements (23) comprises spray nozzles (48) arranged to spray liquid into said wash tub (33) during said washing phase, wherein said flow control arrangement (31 ) is arranged at a lower position in said dishwasher (1 ) than a lowermost spray nozzle (49) of said spray nozzles (48) and at a vertical distance therefrom to form a liquid column in said duct (45) preventing a flow of liquid through said primary outlet (37), when said flow rate is less than said predetermined threshold value.

10. The dishwasher (1 ) according to any one of the preceding claims, comprising a pump (21 ), a liquid reuse tank (50) and a sump (52) arranged at a centre (13) of said wash tub bottom (5), wherein said pump (21 ) is arranged to pump said liquid from said sump (52) to said one or more apertures (9.1 , 9.2) of said drying arrangement (7) during a time period, and arranged to pump said liquid to said liquid reuse tank (50), when said time period has elapsed.

1 1 . A method (100) for drying washed items in a dishwasher (1 ) comprising a wash tub (3) for housing said washed items, wherein said wash tub (3) comprises a wash tub bottom (5) at a bottom of said wash tub (3), wherein said dishwasher (1 ) comprises a drying arrangement (7) for drying said washed items, wherein said drying arrangement (7) comprises one or more apertures (9.1 , 9.2), wherein said method (100) comprises:

directing (101 ) a liquid onto said wash tub bottom (5), having a lower temperature than a temperature of an environment within said wash tub (3), via said one or more apertures (9.1 , 9.2), to create a liquid surface at said wash tub bottom (5) adapted to change a state of a fluid within said wash tub (3) from gaseous state to liquid state.

12. The method (100) according to claim 1 1 , wherein said dishwasher (1 ) comprises a pump (21 ), a liquid reuse tank (50) and a sump (52) arranged at a centre (13) of said wash tub bottom (5), wherein said method (100) further comprises:

pumping (102) said liquid from said sump (52) to said one or more apertures (9.1 , 9.2) of said drying arrangement (7) during a time period, using said pump (21 ), and

- pumping (103) said liquid to said liquid reuse tank (50), when said time period has elapsed, using said pump (21 ).