WO2017088935A1

WO2017088935A1 - Flow control arrangement and dishwasher comprising a flow control arrangement

Info

Publication number: WO2017088935A1
Application number: PCT/EP2015/077973
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 flow control arrangement (1) is provided for controlling flow of liquid in a dishwasher (3). The flow control arrangement (1) comprises an inlet (5), a primary outlet (7), at least one secondary outlet (9.1, 9.2) and an interior volume (11). The flow control arrangement (1) is provided with a constantly open first flow path (12) from said inlet (5) to said primary outlet (7) via said interior volume (11). The arrangement (1) further comprises a valve (13) adapted to control the flow of liquid in a second flow path (14) between said inlet (5) and said least one secondary outlet (9.1, 9.2) in response to a flow rate of liquid within said interior volume. Embodiments herein also relates to a dishwasher (3) comprising a flow control arrangement (1).

Description

FLOW CONTROL ARRANGEMENT AND DISHWASHER COMPRISING A FLOW CONTROL ARRANGEMENT

TECHNICAL FIELD

The present invention relates to a flow control arrangement and a dishwasher comprising a flow control arrangement.

BACKGROUND Today's dishwashers are expected perform a trouble-free operation and 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. These requirements and advantages have led to development of auxiliary systems and features such as drying arrangements configured to dry washed items in a drying phase, auxiliary spray arrangements, liquid reuse tanks, and detergent resolving arrangements. All these systems and features require some form of flow control arrangements capable of controlling flow of liquid in the dishwasher. Many flow control arrangements for controlling flow of liquid in a dishwasher comprises a control unit, a valve and an actuator, where the actuator is arranged to position the valve in different positions upon control of the control unit. Such flow control arrangements are relatively expensive to manufacture and add costs and complexity to the final product, i.e. the dishwasher. It is an advantage at today's consumer markets if high quality products, having auxiliary systems and features, can be manufactured at a low cost. Attempts have been made to provide flow control arrangement circumventing the need for control units and actuators. The document GB 1233349 A relates to a valve controlling flow to sprinkler arms and a conduit based on water pressure within the valve. The valve described in the document GB1233349 A is associated with some problems. One problem is reliability. Another problem is flow resistance within the valve. Still another problem is suitability to different auxiliary systems and features of a dishwasher. SUMMARY

An object of the present invention is to provide an improved control of liquid in a 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 flow control arrangement for controlling flow of liquid in a dishwasher, wherein the flow control arrangement comprises an inlet, a primary outlet, at least one secondary outlet and an interior volume, 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, wherein the flow control arrangement further comprises a valve adapted to control the flow of liquid in a second flow path between the inlet and the least one secondary outlet in response to a flow rate of liquid within the interior volume. Since the flow control arrangement is provided with a constantly open first flow path from the inlet to the primary outlet via the interior volume, the flow control arrangement may easily be arranged to provide a low flow resistance in the first flow path. By having a low flow resistance in the first flow path, less energy will be needed to flow liquid through the first flow path. In addition greater flow rates through the first flow path will be allowed.

Since the flow control arrangement further comprises a valve adapted to control the flow of liquid in the second flow path in response to a flow rate of liquid within the interior volume, the flow of liquid in the second flow path can be controlled simply by controlling the flow rate of liquid within the interior volume, for example by controlling a pump speed of a pump connected to the inlet of the flow control arrangement. Thus, the need for an auxilliary control unit and an actuator is circumvented. Accordingly, the flow control arrangement can be provided at a low cost.

In addition, since the flow control arrangement is provided with a constantly open first flow path from the inlet to the primary outlet via the interior volume, the flow control arrangement is suitable for use in many different applications of a dishwasher. For example, the flow control arrangement may be arranged in a duct transferring washing liquid from a pump to a spray arrangement of the dishwasher, where the first flow path of the flow control arrangement forms part of the duct. As a result, an improved flow control arrangement for controlling flow of liquid 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 valve is adapted to open the second flow path when the flow rate is lower than a predetermined flow rate, and adapted to close the second flow path when the flow rate exceeds the predetermined flow rate.

Optionally, the valve is adapted to close the second flow path when the flow rate is lower than a predetermined flow rate, and adapted to open the second flow path when the flow rate exceeds the predetermined flow rate.

Optionally, the valve comprises a valve body displaceably arranged within the interior volume between an open position and a closed position, wherein the second flow path is open in the open position, and wherein the second flow path is closed in the closed position, and wherein the valve body is arranged to be displaced towards the closed position when being subjected to a flow of liquid within the interior volume having a flow rate exceeding the predetermined flow rate. As a result, a simple and reliable control of flow of liquid in the second flow path is provided.

Optionally, the valve body is arranged to be displaced towards the open position by a force caused by at least one of gravity and a spring when being subjected to a flow of liquid within the interior volume having a flow rate being lower than the predetermined flow rate. As a result, a simple and reliable control of flow of liquid in the second flow path is provided. Optionally, the arrangement comprises an elongated element extending into the interior volume, wherein the elongated element comprises the valve and the second flow path. As a result, a simple arrangement is provided capable of controlling liquid in the second flow path. In addition, a low flow resistance in the first flow path can be ensured. Further embodiments herein aim to provide a dishwasher comprising a flow control arrangement according to any one of the preceding claims. As a result, a dishwasher is provided capable of performing an improved control of liquid. Thus, the above mentioned object is achieved.

Optionally, the dishwasher comprises a pump and a first spray arrangement, wherein the inlet of the flow control arrangement is connected to the pump, wherein the primary outlet of the flow control arrangement is connected to the first spray arrangement, and wherein the at least one secondary outlet of the flow control arrangement is connected to at least one of a second spray arrangement, a liquid reuse tank, and a detergent resolving arrangement. Since the inlet is connected to the pump, and the primary outlet is connected to the first spray arrangement, and since the flow control arrangement is provided with a constantly open first flow path from the inlet to the primary outlet via the interior volume, flow resistance in the first flow path will be low. Thus, the pump can supply liquid to the first spray arrangement in a first flow path having low flow resistance. In addition, since the least one secondary outlet of the flow control arrangement is connected to at least one of a second spray arrangement, a liquid reuse tank, and a detergent resolving arrangement, flow of liquid to one or more of these arrangements can be controlled in a simple and efficient manner, for example by controlling a pump speed of the pump. Accordingly, a dishwasher is provided capable of performing an improved control of liquid.

Optionally, the dishwasher comprises a pump, a wash tub for housing items to be washed, a wash tub bottom arranged at a bottom of the wash tub, one or more spray arrangements arranged to spray washing liquid into the wash tub, and a drying arrangement comprising one or more apertures arranged to direct a liquid onto the wash tub bottom to create a liquid surface at the wash tub bottom adapted to change a state of washing liquid within the wash tub from gaseous state to liquid state, wherein the inlet of the flow control arrangement is connected to the pump, and wherein the primary outlet of the flow control arrangement is connected to the one or more spray arrangements, and wherein the at least one secondary outlet of the flow control arrangement is connected to the one or more apertures, wherein the valve of the flow control arrangement is adapted to open the second flow path when the flow rate is lower than a predetermined flow rate, and adapted to close the second flow path when the flow rate exceeds the predetermined flow rate, wherein.

Since the inlet is connected to the pump, and the primary outlet is connected to the one or more spray arrangements, and since the flow control arrangement is provided with a constantly open first flow path from the inlet to the primary outlet via the interior volume, flow resistance in the first flow path will be low. Thus, the pump can supply liquid to the one or more spray arrangements in a first flow path having low flow resistance. In addition, since the at least one secondary outlet of the flow control arrangement is connected to the one or more apertures, flow of liquid to the one or more apertures of the drying arrangement can be controlled in a simple and efficient manner, for example by controlling a pump speed of the pump. Accordingly, a dishwasher is provided capable of performing an improved control of liquid. Further, 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 at a low cost while maintaining a reliable operation.

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 the drying effect. In addition, a dishwasher is provided which can be manufactured at a low cost since it requires few additional components to achieve a drying of washed items.

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.

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 performing an improved control of liquid and capable of creating the liquid surface at the wash tub bottom, using few components. As a result, cost and complexity of the dishwasher is 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. 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 a and Fig. 1 b illustrate a flow control arrangement for controlling flow of liquid in a dishwasher, according to some embodiments,

Fig. 2a and Fig. 2b illustrate a flow control arrangement for controlling flow of liquid in a dishwasher, according to some embodiments,

Fig. 3 illustrates a dishwasher, and

Fig. 4 illustrates a wash tub of the dishwasher illustrated in Fig. 1 .

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 a and Fig. 1 b illustrate a flow control arrangement 1 for controlling flow of liquid in a dishwasher. The flow control arrangement 1 comprises an inlet 5, a primary outlet 7, at least one secondary outlet 9.1 , 9.2 and an interior volume 1 1. The flow control arrangement 1 is provided with a constantly open first flow path 12 from the inlet 5 to the primary outlet 7 via the interior volume 1 1. The flow control arrangement 1 further comprises a valve 13 adapted to control the flow of liquid in a second flow path 14 between the inlet 5 and the least one secondary outlet 9.1 , 9.2 in response to a flow rate of liquid within the interior volume.

In the embodiments of the flow control arrangement 1 illustrated in Fig. 1 a and Fig. 1 b, the valve 13 is adapted to open the second flow path 14 when the flow rate is lower than a predetermined flow rate, and adapted to close the second flow path 14 when the flow rate exceeds the predetermined flow rate.

In Fig. 1 a, the flow control arrangement 1 is illustrated in a situation in which the flowrate of liquid within the interior volume 1 1 is lower than a predetermined flowrate. As can be seen, the second flow path 14 between the inlet 5 and the at least one secondary outlet 9.1 , 9.2 is open.

In Fig. 1 b, the flow control arrangement 1 is illustrated in a situation in which the flowrate of liquid within the interior volume 1 1 exceeds the predetermined flowrate. As can be seen, the second flow path 14 between the inlet 5 and the at least one secondary outlet 9.1 , 9.2 is closed.

In the embodiments of the flow control arrangement 1 illustrated in Fig. 2a and Fig. 2b, the valve 13 is adapted to close the second flow path 14 when the flow rate is lower than a predetermined flow rate, and adapted to open the second flow path 14 when the flow rate exceeds the predetermined flow rate.

In Fig. 2a, the flow control arrangement 1 is illustrated in a situation in which the flowrate of liquid within the interior volume 1 1 is lower than a predetermined flowrate. As can be seen, the second flow path 14 between the inlet 5 and the at least one secondary outlet 9.1 , 9.2 is closed.

In Fig. 2b, the flow control arrangement 1 is illustrated in a situation in which the flowrate of liquid within the interior volume 1 1 exceeds the predetermined flowrate. As can be seen, the second flow path 14 between the inlet 5 and the at least one secondary outlet 9.1 , 9.2 is open.

In the embodiments of the flow control arrangement 1 illustrated in Fig. 1 a and Fig. 1 b, as well as in the embodiments of the flow control arrangement 1 illustrated in Fig. 2a and Fig. 2b, the valve 13 comprises a valve body 15 displaceably arranged within the interior volume 1 1 between an open position and a closed position, wherein the second flow path 14 is open in the open position, and wherein the second flow path 14 is closed in the closed position. In the embodiments of the flow control arrangement 1 illustrated in Fig. 1 a and Fig. 1 b, the valve body 15 is arranged to be displaced towards the open position by a force caused by at least one of gravity and a spring 16 when being subjected to a flow of liquid within the interior volume 1 1 having a flow rate being lower than the predetermined flow rate. Such open position is illustrated in Fig. 1 a.

The valve body 15 illustrated in Fig. 1 a and Fig. 1 b is arranged to be displaced towards the closed position when being subjected to a flow of liquid within the interior volume 1 1 having a flow rate exceeding the predetermined flow rate. Such closed position is illustrated in Fig. 1 b.

In the embodiments of the flow control arrangement 1 illustrated in Fig. 2a and Fig. 2b, the valve body 15 is arranged to be displaced towards the closed position by a force caused by at least one of gravity and a spring 16 when being subjected to a flow of liquid within the interior volume 1 1 having a flow rate being lower than the predetermined flow rate. Such closed position is illustrated in Fig. 2a.

The valve body 15 illustrated in Fig. 2a and Fig. 2b is arranged to be displaced towards the open position when being subjected to a flow of liquid within the interior volume 1 1 having a flow rate exceeding the predetermined flow rate. Such open position is illustrated in Fig. 2b.

In the embodiments of the flow control arrangement 1 illustrated in Fig. 1 a and Fig. 1 b as well as in the embodiments of the flow control arrangement 1 illustrated in Fig. 2a and Fig. 2b, the predetermined flowrate may be determined by choosing cross sectional area of the valve body 15 subjected to the flow of liquid within the interior volume 1 1 , cross sectional area of the first flow path 12, weight of the valve body 15, strength and direction of force of the spring 16, and hydrodynamic properties of the valve body 15.

Due to the different layout and functionality between the embodiments illustrated in Fig. 1 a and 1 b compared to the embodiments illustrated in Fig. 2a and 2b, the embodiments may be used for different applications such as for controlling flow of liquid to one or more of auxiliary spray arrangement, liquid reuse tanks, and detergent resolving arrangements. In addition, the flow control arrangement 1 may be used in order to extend control of flow of liquid by stopping flow of liquid to one or more spray

arrangement when needed. In the embodiments of the flow control arrangement 1 illustrated in Fig. 1 a and Fig. 1 b as well as in the embodiments of the flow control arrangement 1 illustrated in Fig. 2a and Fig. 2b, the flow control arrangement 1 comprises an elongated element 17 extending into the interior volume 1 1 , wherein the elongated element 17 comprises the valve 13 and the second flow path 14. Thereby, a simple and reliable flow control arrangement 1 is provided and a low flow resistance in the first flow path 12 is ensured.

Fig. 3 illustrates a dishwasher 3.

Fig. 4 illustrates a wash tub 33 of the dishwasher 3 illustrated in Fig. 1. According to some embodiments, the dishwasher comprises a flow control arrangement 1 , as illustrated in Fig. 1 a and 1 b. According to further embodiments, the dishwasher comprises a flow control arrangement 1 , as illustrated in Fig. 2a and 2b. The dishwasher 3 further comprises a pump 21 , a wash tub 33 for housing items to be washed, a wash tub bottom 35 arranged at a bottom of the wash tub 33, and one or more spray arrangements 23 arranged to spray washing liquid into the wash tub 33,

The inlet of the flow control arrangement 1 is connected to the pump 21 , and the primary outlet of the flow control arrangement 1 is connected to the first spray arrangement 23. According to some embodiments, the at least one secondary outlet of the flow control arrangement 1 is connected to at least one of a second spray arrangement 25, a liquid reuse tank 27, and a detergent resolving arrangement 29. Thereby, control of liquid to one of more of such arrangements can be performed in a simple and efficient manner by controlling pump speed of the pump 21. As indicated above, in these embodiments, the dishwasher may comprise a flow control arrangement 1 as illustrated in Fig. 1 a and Fig. 1 b, or flow control arrangement 1 as illustrated in Fig. 2a and Fig. 2b. Accordingly, in these embodiments, the dishwasher may either comprise a flow control arrangement 1 where the valve is adapted to open the second flow path when the flow rate is lower than a predetermined flow rate, and adapted to close the second flow path when the flow rate exceeds the predetermined flow rate, or a flow control arrangement 1 where the valve is adapted to close the second flow path when the flow rate is lower than a predetermined flow rate, and adapted to open the second flow path when the flow rate exceeds the predetermined flow rate. The choice between the embodiments may depend on factors such as type of arrangement connected to the at least one secondary outlet of the flow control arrangement 1 and functionality of other systems and arrangements of the dishwasher. The term connected to is intended to encompass a flow connection.

According to further embodiments, the dishwasher comprises a drying arrangement 37 comprising one or more apertures 39.1 , 39.2 arranged to direct a liquid onto the wash tub bottom 35 to create a liquid surface at the wash tub bottom 35 adapted to change a state of washing liquid within the wash tub 33 from gaseous state to liquid state. In these embodiments, the dishwasher comprises a flow control arrangement 1 as is illustrated in Fig. 1 a and Fig. 1 b wherein the inlet 5 of the flow control arrangement 1 is connected to the pump 21 , and wherein the primary outlet 7 of the flow control arrangement 1 is connected to the one or more spray arrangements 23, and wherein the at least one secondary outlet 9.1 , 9.2 of the flow control arrangement 1 is connected to the one or more apertures 39.1 , 39.2. The valve 13 of the flow control arrangement 1 is adapted to open the second flow path 14 when the flow rate is lower than a predetermined flow rate, and adapted to close the second flow path 14 when the flow rate exceeds the predetermined flow rate. The pump 21 is configured to cause the flowrate to exceed the predetermined flow rate during a washing phase of the dishwasher 3 and configured to cause the flow rate to be less than the predetermined flow rate during a drying phase of the dishwasher 3. As a result, during the washing phase, the valve 13 of the flow control arrangement 1 will close the second flow path 14 and no liquid will be directed onto the wash tub bottom 35. During the drying phase, the valve 13 of the flow control arrangement 1 will open the second flow path 14. As a result, the drying arrangement 37 will direct the liquid onto the wash tub bottom 35, via the one or more apertures 39.1 , 39.2, 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 33 from gaseous state to liquid state by having a lower temperature than the environment within the wash tub 33. The change a state of a fluid within the wash tub 33 from gaseous state to liquid state may also be referred to as a condensation of fluid within the wash tub 33.

To ensure that the liquid surface has a lower temperature than the environment within the wash tub 33, the drying arrangement 37 may further comprise heating arrangements (not shown in Fig. 4) arranged to supply heat to the environment within the wash tub 33 prior to, or during a drying phase of the dishwasher. In addition, the liquid directed onto the wash tub bottom 35 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 33 from gaseous state to liquid state. An efficient rate of change of state of a fluid within the wash tub 33 from gaseous state to liquid state may also be referred to as an efficient condensation rate. The fluid within the wash tub 33 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 37 is arranged to create the liquid surface at the wash tub bottom 35 by filling the wash tub bottom 35 with liquid such that a stagnant pool of liquid is formed at the wash tub bottom 35.

As an alternative, or in addition, the drying arrangement 37 is arranged to create the liquid surface at the wash tub bottom 35 by, at least during a time period, continuously directing the liquid onto the wash tub bottom 35, via the one or more apertures 39.1 , 39.2, to create flow of liquid flowing over the surface of the wash tub bottom 35.

As illustrated in Fig. 4, the one or more apertures 39.1 , 39.2 are arranged at a peripheral edge 11 of the wash tub bottom 35. The wash tub bottom 35 is inclined essentially towards a centre 42 of the wash tub bottom 35, and wherein the one or more apertures 39.1 , 39.2 are arranged to direct the liquid along the peripheral edge 41 of the wash tub bottom 35. The drying arrangement 37 comprises a first aperture 39.1 and a second aperture 39.2, wherein the first aperture 39.1 and the second aperture 39.2 are arranged to direct the liquid in essentially opposite directions. Thereby, the liquid will be guided along the peripheral edge 41 of the wash tub bottom 35 and will flow from the peripheral edge 41 towards the centre 42 of the wash tub bottom 35. Thereby, an even and coherent liquid surface can be created using a low number of apertures 39.1 , 39.2. Using a low number of apertures 39.1 , 39.2 reduces cost and complexity of the drying arrangement and reduces the risk of particles becoming trapped in the apertures 39.1 , 39.2 during operation since apertures 39.1 , 39.2 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. 4, the first aperture 39.1 and the second aperture 39.2 may be arranged in a common housing which facilitates wiring of the supply of liquid to the respective aperture 39.1 , 39.1. As a result, cost and complexity of the drying arrangement 37 is further reduced.

According to some embodiments, the drying arrangement 37 comprises a control unit 43 arranged to control a flowrate of the liquid directed onto the wash tub bottom 35 such that the flowrate varies periodically. The control unit 43 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 33. The control unit 43 may be arranged to control a flowrate of the liquid directed onto the wash tub bottom 35 such that a certain flowrate of liquid is directed onto the wash tub bottom 35 during first time periods and no flow of liquid is directed onto the wash tub bottom 35 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 35, the relatively cold wash tub bottom 35 will also provide a change of state of a fluid within the wash tub 33 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 37 comprises a humidity sensor 44 and the control unit 43, wherein the humidity sensor 44 is arranged to sense humidity within the wash tub 33, and wherein the control unit 43 is arranged to control a flowrate of the liquid directed onto the wash tub bottom 35 based on the humidity.

Thereby, the control unit 43 will control the condensation of fluid within the wash tub 33 in dependence of the humidity within the wash tub 33. As a result, less water and energy may be used during a drying phase of the dishwasher. In addition, the control unit 43 may determine, on the basis of the humidity within the wash tub 33, when to end a drying phase.

According to some embodiments, the control unit 43 is arranged to control a flowrate of the liquid directed onto the wash tub bottom 35 the such that the drying arrangement 37 periodically directs the liquid onto the wash tub bottom 35 with at least one of intervals and durations being based on the humidity of air within the wash tub 35. 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 33.

As illustrated in Fig. 4, the dishwasher comprising the wash tub 33 further comprises a duct 45 connecting the primary outlet 7 of the flow control arrangement 1 , illustrated in Fig. 1 a and Fig. 1 b, and the one or more spray arrangements 23, illustrated in Fig. 4. The one or more spray arrangements 23 comprises spray nozzles 47 arranged to spray liquid into the wash tub 33 during the washing phase, and the flow control arrangement 1 is arranged at a lower position in the dishwasher than a lowermost spray nozzle 49 of the spray nozzles 47 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 7, 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 39.1 , 39.2 or to the spray nozzles 47 of the one or more spray arrangements 23 simply by controlling the pump speed of the pump 21. The embodiments illustrated in Fig. 4 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 43 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 43 is arranged to control the flow control vale 53 to the first position. During a drying phase, the control unit 43 is arranged to control the flow control vale 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 37 will direct a liquid onto the wash tub bottom 35, via the one or more apertures 39.1 , 39.2, to create a liquid surface at the wash tub bottom 35, and the formation of the liquid column in the duct 45 is ensured.

As specified above, the drying arrangement 37 may be arranged to create the liquid surface at the wash tub bottom 35 by, at least during a time period, continuously directing the liquid onto the wash tub bottom 35, via the one or more apertures 39.1 , 39.2, to create flow of liquid flowing over the surface of the wash tub bottom 35. This may be achieved by the pump 21 continuously supplying liquid to the one or more apertures 39.1 , 39.2. The liquid will flow towards the centre 42 of the wash tub bottom 35, where a sump is arranged. The sump is in flow connection with the pump 21. The pump 21 may thus circulate a certain volume of liquid over the wash tub bottom 5 for a certain time period. A length of such a certain time period may for example be 10-20 minutes. When the certain time period has elapsed, the pump 21 may pump the volume of liquid to a drain and replace it 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 35 can be ensured. In addition, according to some embodiments, after a circulation phase, the pump 21 may pump the volume of liquid to a liquid re-use tank, where the liquid may cool down and be re-used in a subsequent circulation phase.

Claims

1. A flow control arrangement (1 ) for controlling flow of liquid in a dishwasher (3),

wherein said flow control arrangement (1 ) comprises an inlet (5), a primary outlet (7), at least one secondary outlet (9.1 , 9.2) and an interior volume (1 1 ), characterized in that said flow control arrangement (1 ) is provided with a constantly open first flow path (12) from said inlet (5) to said primary outlet (7) via said interior volume (1 1 ), wherein said flow control arrangement (1 ) further comprises a valve (13) adapted to control the flow of liquid in a second flow path (14) between said inlet (5) and said least one secondary outlet (9.1 , 9.2) in response to a flow rate of liquid within said interior volume.

2. The arrangement (1 ) according to claim 1 , wherein said valve (13) is adapted to open said second flow path (14) when said flow rate is lower than a predetermined flow rate, and adapted to close said second flow path (14) when said flow rate exceeds said predetermined flow rate.

3. The arrangement (1 ) according to claim 1 , wherein said valve (13) is adapted to close said second flow path (14) when said flow rate is lower than a predetermined flow rate, and adapted to open said second flow path (14) when said flow rate exceeds said predetermined flow rate.

4. The arrangement (1 ) according to claim 1 or 2, wherein said valve (13) comprises a valve body (15) displaceably arranged within said interior volume (1 1 ) between an open position and a closed position, wherein said second flow path (14) is open in said open position, and wherein said second flow path (14) is closed in said closed position, and wherein said valve body (15) is arranged to be displaced towards said closed position when being subjected to a flow of liquid within said interior volume (1 1 ) having a flow rate exceeding said predetermined flow rate. 5. The arrangement (1 ) according to claim 4, wherein said valve body (15) is arranged to be displaced towards said open position by a force caused by at least one of gravity and a spring (16) when being subjected to a flow of liquid within said interior volume (1 1 ) having a flow rate being lower than said predetermined flow rate.

The arrangement (1 ) according to any one of the preceding claims, comprising an elongated element (17) extending into said interior volume (11 ), wherein said elongated element (17) comprises said valve (13) and said second flow path (14).

A dishwasher (3) comprising a flow control arrangement (1 ) according to any one of the preceding claims.

The dishwasher (3) according to claim 7, comprising a pump (21 ) and a first spray arrangement (23), wherein said inlet (5) of said flow control arrangement (1 ) is connected to said pump (21 ), wherein said primary outlet (7) of said flow control arrangement (1 ) is connected to said first spray arrangement (23), and wherein said at least one secondary outlet (9.1 , 9.2) of said flow control arrangement (1 ) is connected to at least one of a second spray arrangement (25), a liquid reuse tank (27), and a detergent resolving arrangement (29).

The dishwasher (3) according to claim 7 wherein said dishwasher (3) comprises:

- a pump (21 ),

a wash tub (33) for housing items to be washed,

a wash tub bottom (35) arranged at a bottom of said wash tub (33),

one or more spray arrangements (23) arranged to spray washing liquid into said wash tub (33), and

a drying arrangement (37) comprising one or more apertures (39.1 , 39.2) arranged to direct a liquid onto said wash tub bottom (35) to create a liquid surface at said wash tub bottom (35) adapted to change a state of washing liquid within said wash tub (33) from gaseous state to liquid state,

wherein said inlet (5) of said flow control arrangement (1 ) is connected to said pump (21 ), and wherein said primary outlet (7) of said flow control arrangement (1 ) is connected to said one or more spray arrangements (23), and wherein said at least one secondary outlet (9.1 ,

9.2) of said flow control arrangement (1 ) is connected to said one or more apertures (39.1 , 39.2), wherein said valve (13) of said flow control arrangement (1 ), is adapted to open said second flow path (14) when said flow rate is lower than a predetermined flow rate, and adapted to close said second flow path (14) when said flow rate exceeds said predetermined flow rate.

10. The dishwasher (3) according to claim 9, wherein said pump (21 ) is configured to cause said flowrate to exceed said predetermined flow rate during a washing phase of said dishwasher (3) and configured to cause said flow rate to be less than said predetermined flow rate during a drying phase of said dishwasher (3).

1 1 . The dishwasher (3) according to claim 10, comprising a duct (45) connecting said primary outlet (7) of said flow control arrangement (1 ) and said one or more spray arrangements (23), wherein said one or more spray arrangements (23) comprises spray nozzles (47) arranged to spray liquid into said wash tub (33) during said washing phase, wherein said flow control arrangement (1 ) is arranged at a lower position in said dishwasher (3) than a lowermost spray nozzle (49) of said spray nozzles (47) and at a vertical distance therefrom to form a liquid column in said duct (45) preventing a flow of liquid through said primary outlet (7), when said flow rate is less than said predetermined threshold value.