EP4698031A1

EP4698031A1 - Dishwasher comprisng improved flow controllor assembly

Info

Publication number: EP4698031A1
Application number: EP23720619.8A
Authority: EP
Inventors: Alberto Santarossa; Sandro BROVEDANI
Original assignee: Electrolux Appliances AB
Current assignee: Electrolux Appliances AB
Priority date: 2023-04-20
Filing date: 2023-04-20
Publication date: 2026-02-25
Also published as: CN120813286A; AU2023443819A1; WO2024217691A1

Abstract

A dishwasher is provided. The dishwasher (100) comprises a washing fluid conduit system (118) comprising a plurality of washing fluid supply conduits each one for supplying washing fluid to at least one corresponding component of the dishwasher; a sump (114) for collecting washing fluid, the sump comprising a plurality of sump outlets (138, 140, 142) each one for a corresponding washing fluid supply conduit of the plurality; a pump (116) for pumping washing fluid from the sump to the washing fluid conduit system; a flow controller assembly operable for selectively enabling washing fluid flow from the sump to selected one or more washing fluid supply conduits. The flow controller assembly comprises a discoidal flow diverter (152) comprising a plurality of diverter apertures (153); a positioning system configured to rotate the flow diverter relative to the sump outlets across a plurality of predetermined diverter positions, each diverter position providing for the alignment between one or more diverter apertures and one or more respective sump outlets, thereby enabling washing fluid flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit. The positioning system comprises: a plurality of cam elements (C(i)) coupled to the flow diverter, each cam element being associated with a corresponding predetermined diverter position, each cam element extending along a corresponding arc of the flow diverter, said plurality of cam elements comprising a reference cam element C(1) having an arc length different from the arc lengths of the other cam elements of the plurality; a motor (156) configured to rotate the flow diverter; a cam follower system (180) comprising a cam follower element (182) configured to mechanically interact with the cam elements and interact with a detection switch (184) so as to commute the detection switch to a first state when the cam follower element is mechanically interacting with a cam element and to commute the detection switch to a second state when the cam follower element is not mechanically interacting with a cam element; a control unit (125) configured to assess a position of the flow diverter among the predetermined diverter positions and to drive the motor according to the assessed position, wherein the control unit is configured to assess said position of the flow diverter by: assessing a position corresponding to a reference one of the predetermined diverter positions associated with the reference cam element based on durations of interaction intervals during which the detection switch is in the first state; and assessing a position corresponding to one of the predetermined diverter positions different from the reference diverter position by counting a number of times the detection switch is commuted to a selected state between the first state and the second state after the assessment of the reference diverter position.

Description

DISHWASHER COMPRISNG IMPROVED FLOW CONTROLLOR ASSEMBLY

DESCRIPTION

Technological background of the invention

Technical Field of the invention

The present invention generally relates to a dishwasher, and more particularly, to a flow controller assembly for controlling washing fluid flow from a sump of the dishwasher to a washing fluid conduit system of the dishwasher.

Brief overview of the state of the art

In dishwashers, a flow controller assembly is used to direct washing fluid from a sump to selected washing fluid supply conduit systems. The flow controller assembly is utilized to supply washing fluid to the interior of the dishwasher in a manner consistent with the selected dishwasher cleaning cycle to suitably clean the dishes, utensils, pots, pans and any other items placed in the dishwasher for cleaning. These flow controller assemblies are typically located proximate the dishwasher sump.

Patent Application US 2014/0182625 discloses a dishwasher comprising a channel switch unit allowing the wash water pumped by a wash pump to flow selectively to at least one of three wash arms. The channel switch unit includes a rotary plate which controls the flow of wash water while rotated. The rotary plate is positioned between a channel switch unit housing and a sump cover and selectively opens/closes connection taps of the sump cover. A plurality of switch holes is formed through the rotary plate. As the rotary plate is rotated, the switch holes of the rotary plate move to the position corresponding to at least one of the connection taps and the wash water in the switch water-collecting part is sprayed from at least one of the plurality of wash arms.

Patent US 8,915,257 discloses a water-bearing domestic appliance, comprising a water diverter having at least one adjustable fluid distribution element, particularly a rotating disk, to which a fluid to be discharged through one or more fluid discharge lines can be supplied from a fluid supply line, wherein the at least one adjustable fluid distribution element includes a plurality of passage openings disposed on a flat upper surface of the at least one adjustable fluid distribution element and a plurality of intake regions each corresponding to one of the plurality of passage openings.

US 9980624 discloses a variable position diverter that provides wash fluid to selected combinations of outlet ports and spray assemblies. The diverter includes a housing having a plurality of outlet ports and a valve disk having a plurality of apertures. The valve disk is rotated relative to the housing to align one or more of the plurality of apertures with one or more of the plurality of outlet ports to selectively control the flow of wash fluid through a plurality of spray assemblies.

Summary of the Invention

As highlighted above, flow controller assemblies typically comprise a diverter configured to be rotated across predetermined positions to selectively align with various taps/fluid lines/outlets/ports in order to enable the selective supply of washing liquid toward selected sections of the dishwasher based on the (phase of the) washing cycle being carried out by the dishwasher.

The higher the number of available predetermined positions, the higher the number of possible different configurations of the dishwasher.

In order to correctly operate the dishwasher, the dishwasher may be expediently provided with a system for assessing the current position of the diverter. Such a system for assessing the current position of the diverter should be accurate to identify the correct position of the diverter and at the same time it should not be expensive or too bulky. The accuracy is a particularly troublesome requirement in case the number of available predetermined positions increases.

An aspect of the present invention relates to a dishwasher comprising a washing fluid conduit system comprising a plurality of washing fluid supply conduits each one for supplying washing fluid to at least one corresponding component of the dishwasher.

The dishwasher further comprises a sump for collecting washing fluid.

The sump comprises a plurality of sump outlets each one for a corresponding washing fluid supply conduit of the plurality.

The dishwasher further comprises a pump for pumping washing fluid from the sump to the washing fluid conduit system.

The dishwasher further comprises a flow controller assembly operable for selectively enabling washing fluid flow from the sump to selected one or more washing fluid supply conduits. The flow controller assembly comprises a discoidal flow diverter comprising a plurality of diverter apertures.

The flow controller assembly comprises a positioning system configured to rotate the flow diverter relative to the sump outlets across a plurality of predetermined diverter positions, each diverter position providing for the alignment between one or more diverter apertures and one or more respective sump outlets, thereby enabling washing fluid flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit.

The positioning system comprises a plurality of cam elements coupled to the flow diverter.

Each cam element is associated with a corresponding predetermined diverter position.

Each cam element extends along a corresponding arc of the flow diverter.

Said plurality of cam elements comprises a reference cam element having an arc length different from the arc lengths of the other cam elements of the plurality.

The positioning system comprises a motor configured to rotate the flow diverter.

The positioning system comprises a cam follower system comprising a cam follower element configured to mechanically interact with the cam elements and interact with a detection switch so as to commute the detection switch to a first state when the cam follower element is mechanically interacting with a cam element and to commute the detection switch to a second state when the cam follower element is not mechanically interacting with a cam element.

The positioning system comprises a control unit configured to assess a position of the flow diverter among the predetermined diverter positions and to drive the motor according to the assessed position.

The control unit is configured to assess said position of the flow diverter by:

- assessing a position corresponding to a reference one of the predetermined diverter positions associated with the reference cam element based on durations of interaction intervals during which the detection switch is in the first state;

- assessing a position corresponding to one of the predetermined diverter positions different from the reference diverter position by counting a number of times the detection switch is commuted to a selected state between the first state and the second state after the assessment of the reference diverter position.

In this way, by exploiting the reference diverter position as a reference, it is advantageously possible to efficiently drive a flow diverter across a substantially large number of different predetermined diverter positions without having to use for each predetermined diverter positions a corresponding cam element having a different arc length.

Indeed, thanks to the proposed solution, it is in principle sufficient to provide cam elements having two different arc lengths only (one for the reference cam element and one for the other cam elements) so as to be capable of distinguishing the reference cam element from the other cam elements. Tolerance problems due to excessively similar cam elements (in terms of arc lengths) are therefore advantageously avoided even in presence of a large number of predetermined diverter positions (and therefore in presence of a large number of cam elements).

According to an embodiment of the present invention, the control unit is configured to store a counter indicative of the position of the flow diverter among the predetermined diverter positions.

According to an embodiment of the present invention, the control unit is configured to set the counter to a first value upon the assessment that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position.

According to an embodiment of the present invention, the control unit is configured to update the value of the counter each time the detection switch is commuted to the selected state after the assessment of the reference predetermined diverter position.

According to an embodiment of the present invention, each cam element of the plurality that is different from the reference cam element has an arc length that is lower than an arc length of the reference cam element.

According to an embodiment of the present invention, the control unit is configured to assess that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration higher than a first threshold.

According to an embodiment of the present invention, the control unit is configured to assess that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration that is both:

- higher than said first threshold, and

- lower than a second threshold, said second threshold being higher than said first threshold.

According to an embodiment of the present invention, the control unit is configured to generate a warning indicative of an invalid position of the flow diverter upon the assessment of at least one between:

- an interaction interval having a duration higher than said second threshold,

- an interaction interval having a duration lower than a third threshold, said third threshold being lower than said first threshold.

According to an embodiment of the present invention, said second threshold has a value depending on the arc length of the reference cam element.

According to an embodiment of the present invention, said first threshold has a value depending on the arc lengths of the cam elements of the plurality that are different from the reference cam element.

According to an embodiment of the present invention, the cam elements of the plurality different from the reference cam element have all a same arc length.

According to an embodiment of the present invention, the motor is configured to rotate the flow diverter at a constant rotation speed when driven by the control unit.

According to an embodiment of the present invention, each cam element protrudes parallel to a rotation axis of the flow diverter.

According to an embodiment of the present invention, the control unit is configured to generate a malfunctioning warning indicative of a malfunctioning of the motor and/or of the cam follower system if a timeout expires before the assessment of a new commutation of the detection switch following a turning on of the motor.

According to an embodiment of the present invention, the control unit is configured to receive an indication of a target one among the predetermined diverter positions.

According to an embodiment of the present invention, the control unit is configured to drive the motor to rotate the flow diverter until the flow diverter has been assessed to reach an angular position corresponding to said target predetermined flow diverter position.

According to an embodiment of the present invention, the control unit is configured to turn off the motor when the flow diverter has been assessed to reach an angular position corresponding to said target predetermined diverter position.

According to an embodiment of the present invention, the control unit is configured to turn on the pump, thereby causing washing fluid flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit.

According to an embodiment of the present invention, said indication of a target one among the predetermined diverter positions depends on a phase of a selected washing cycle being performed by the dishwasher. According to an embodiment of the present invention, the control unit is configured to carry out the following operation at the power on of the dishwasher:

- if the detection switch is assessed to be in the first state, drive the motor until the detection switch is assessed to commute to the second state.

According to an embodiment of the present invention, the positioning system further comprises a driver module configured to:

- generate a motor driving signal based on a control signal generated by the control unit;

- providing motor driving signals to terminals of the motor.

According to an embodiment of the present invention, the detection switch comprises a first electric terminal electrically coupled to a terminal of the motor and a second electric terminal electrically coupled to an input of the control unit for providing a sensing signal indicative of the state of the detection switch.

According to an embodiment of the present invention, when the detection switch is in the first state, the first electric terminal is electric coupled to the second electric terminal.

According to an embodiment of the present invention, when the detection switch is in the second state, the first electric terminal is electrically decoupled from the second electric terminal.

According to an embodiment of the present invention, the driver module and the control unit are electrically supplied by DC supply voltages.

According to an embodiment of the present invention, said DC supply voltages are lower than 20 Volts.

According to an embodiment of the present invention, the positioning system further comprises a cam support element coaxially coupled to the flow diverter, said cam elements being located on said cam support element.

According to an embodiment of the present invention, said components of the dishwasher comprise at least one among:

- a dishwasher spray arm;

- a dishwasher detergent dispenser;

- a filter of the sump;

- a dishwasher reservoir tank;

- a dishwasher heat exchanger.

Another aspect of the present invention relates to a method for operating a dishwasher.

The method comprises selectively enabling washing fluid flow from a dishwasher sump to selected one or more washing fluid supply conduits of a dishwasher washing fluid conduit system.

Said selectively enabling comprises rotating a discoidal flow diverter relative to sump outlets of the sump across a plurality of predetermined diverter positions, each sump outlet corresponding to a corresponding washing fluid supply conduit.

Each diverter position provides for the alignment between one or more diverter apertures on the flow diverter and one or more respective sump outlets, thereby enabling washing fluid flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit.

A plurality of cam elements is coupled to the flow diverter, each cam element being associated with a corresponding predetermined diverter position, each cam element extending along a corresponding arc of the flow diverter, said plurality of cam elements comprising a reference cam element having an arc length different from the arc lengths of the other cam elements of the plurality.

Said selectively enabling comprises assessing a position of the flow diverter among the predetermined diverter positions through a cam follower system comprising a cam follower element configured to mechanically interact with the cam elements and interact with a detection switch so as to commute the detection switch to a first state when the cam follower element is mechanically interacting with a cam element and to commute the detection switch to a second state when the cam follower element is not mechanically interacting with a cam element.

Said assessing said position of the flow diverter comprises measuring durations of one or more interaction intervals during which the detection switch is in the first state.

Said assessing said position of the flow diverter comprises assessing a position corresponding to a reference one of the predetermined diverter positions associated with the reference cam element based on said measured durations of said one or more interaction intervals.

Said assessing said position of the flow diverter comprises counting a number of times the detection switch is commuted to a selected state between the first state and the second state after the assessment of the reference diverter position.

Said assessing said position of the flow diverter comprises assessing a position corresponding to one of the predetermined diverter positions different from the reference diverter position based on said counted a number of times.

According to an embodiment of the present invention, the method comprises setting a counter, indicative of the position of the flow diverter among the predetermined diverter positions, to a first value upon the assessment that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position.

According to an embodiment of the present invention, the method comprises updating the value of the counter each time the detection switch is commuted to the selected state after the assessment of the reference predetermined diverter position.

According to an embodiment of the present invention, the method further comprises assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration higher than a first threshold.

According to an embodiment of the present invention, the method further comprises assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration that is both:

- higher than said first threshold, and

According to an embodiment of the present invention, the method further comprises generating a warning indicative of an invalid position of the flow diverter upon the assessment of at least one between:

- an interaction interval having a duration higher than said second threshold,

Brief description of the appended drawings

These and other features and advantages of the present invention will be made apparent by the following detailed description of possible exemplifying and not restrictive embodiments of the present invention, description that will be carried out referring to the accompanying drawings. In the drawings:

Figure 1 is a perspective view of a dishwasher according to an embodiment of the invention; Figure 2 is a perspective view of a sump and of a pump of the dishwasher of Figure 1 according to an embodiment of the present invention;

Figure 3 is an expanded view of the sump of Figure 1 and of a flow controller assembly according to an embodiment of the present invention;

Figure 4A is a perspective view from above of a cam support element of the flow controller assembly according to an embodiment of the present invention;

Figure 4B is a perspective view from below of the cam support element of Figure 4A according to an embodiment of the present invention;

Figure 5 is a detailed perspective view of the cam support element and of portions of a cam follower system according to an embodiment of the present invention;

Figure 6 illustrates an evolution over time of the state of the detection switch according to an exemplary embodiment of the invention;

Figures 7A - 7B illustrate a flow chart of main operations carried out by the control unit 125 of the positioning system according to an embodiment of the present invention, and

Figure 8 illustrates a non-limitative example of circuit elements of (a portion of) the positioning system of the flow controller assembly according to an exemplary embodiment of the present invention.

Detailed description of exemplary embodiments of the invention

Figure 1 illustrates a dishwasher 100 according to an embodiment of the present invention. The dishwasher 100 has top portion 102, bottom portion 104, and tub 106 that extends between the top portion 102 and the bottom portion 104. The tub, top and bottom portions are represented in dashed font in Figure 1. The top portion 102 and the bottom portion 104 define a chamber 103. A bottom panel 108 (shown as partially broken away in Figure 1 to show internal detail) is located in the chamber 103 proximate the bottom portion 104. Tub 106 comprises a plurality of walls 110. Dishes, utensils, and other dishware (also referred to herein as “contents” of the dishwasher 100) may be placed in chamber 103 for being treated, e.g., cleaned. The dishwasher 100 may also include slidable lower and upper racks (not shown) for holding the contents of the dishwasher. The racks are movable into and out of the chamber 103. Also represented in dashed line Figure 1 is a door 112 that may be pivotably connected with the tub 106 to selectively permit access to chamber 103 and seal tub 106 when the dishwasher 100 is operating (e.g., when the contents of the dishwasher 100 are treated).

According to an embodiment of the present invention, the dishwasher 100 includes a sump 114 in which washing fluid is collected, typically under the influence of gravity. The washing fluid is used by the dishwasher 100 to treat, e.g., clean, wash, and rinse, the contents of the dishwasher 100 and may include, for example, any combination of water, fresh water, softened water, water mixed with detergent, rinse aid, and any other suitable washing and/or rinsing fluid.

According to an embodiment of the present invention, the washing fluid collected in the sump 114 may be pumped by a circulation pump 116 through a washing fluid conduit system 118 comprising a plurality of washing fluid supply conduits each one that is fluid connected to a corresponding component of the dishwasher 100, such as for example one or more spray arms, for supplying washing fluid thereto.

In the exemplary embodiment illustrated in Figure 1, the washing fluid conduit system 118 comprises, among the others: a washing fluid supply conduit connected to a top spray device 120; a washing fluid supply conduit connected to a middle spray arm 122; a washing fluid supply conduit connected to a lower spray arm 124.

The concepts of the present invention can be directly applied to cases in which a different number of spray arms are provided.

According to the embodiment of the invention illustrated in Figure 1, the top spray device 120 is proximate the top portion 102 of the dishwasher, the lower spray arm 124 is proximate the bottom panel 108, and middle spray arm 122 is located between the top and lower spray arms.

The concepts of the present invention can be directly applied to cases in which the spray arms are located in different positions.

The spray devices/arms 120, 122, and 124 are located in the chamber 103, and are configured for spraying the washing fluid, under pressure, onto the contents in chamber 103 during dishwasher use.

According to an embodiment of the present invention, the dishwasher 100 further comprises a control unit 125 (schematically illustrated in figure in terms of a dashed square) configured to control the operation of the dishwasher 100 by driving components thereof based on a (phase of a) washing cycle being carried out by the dishwasher 100. For example, the control unit 125 is configurated to selectively operate the pump 116 to send washing fluid to at least one of the spray arms/devices 120, 122, and/or 124. In some embodiments, the control unit 125 may include a memory for storage of data such as routines for operation of the dishwasher 100.

In the embodiment of the invention illustrated in Figure 1, the control unit 125 is located at the top portion 102 of the dishwasher 100. The control unit 125 may be located in in different parts of the dishwasher 100, such as for example at the bottom portion 104 of the dishwasher 100.

According to an embodiment of the present invention, the sump 114 is fluidly coupled to a flow controller assembly, which will be described in more detail below, configured to selectively enable washing fluid flow from the sump 114 to selected one or more washing fluid supply conduits.

Figure 2 is a perspective view of the sump 114 and of the pump 116 according to an embodiment of the present invention. Figure 3 is an expanded view of the sump 114 and of the flow controller assembly, globally identified in the figures with reference 150, according to an embodiment of the present invention.

According to an embodiment of the present invention, the sump 114 comprises a sump housing 132 defining a sump region 151 configured to contain washing fluid. A collector opening 131 is provided on a top side of the sump housing 132 for allowing washing fluid coming from the tub 106 be collected into the sump region 151 under the influence of gravity.

According to an embodiment of the present invention, a removable filter unit (not illustrated in Figures 2 and 3) is provided at the collector opening 131 for filtering the washing liquid being collected into the sump 114.

According to an embodiment of the present invention, the pump 116 has an input port connected to an output port 133 of the sump 114 (see Figure 3) for receiving washing fluid contained in the sump region 151 of the sump 114.

According to an embodiment of the present invention, the flow controller assembly 150 is housed in a corresponding flow controller housing 136 having an inlet 169 fluidly connected to an output port of the pump 116. According to an embodiment of the present invention, the flow controller housing 136 is connected to the sump 114, for example by means of engagement means 137, and defines a volume adapted to receive the washing fluid pumped by the pump 116 through the inlet 169.

According to an embodiment of the present invention, a housing opening 155 is provided on a top side of the flow controller housing 136 that, as will be described in the following, can be selectively set in fluid communication with one or more sump outlets 138, 140, 142 provided at the sump 114 by elements of the flow controller assembly 150. According to an embodiment of the present invention, each one of said sump outlets 138, 140, 142 is in fluid communication with a corresponding fluid supply conduit of the washing fluid conduit system 118 that is in turn fluid connected to a corresponding component of the dishwasher 100. According to the embodiment of the invention illustrated in the figures, the sump outlets 138, 140, 142 are located on a plate on the side of the sump 114. However, similar considerations apply in case the sump outlets are arranged on a different portion of the sump 114.

In the exemplary embodiment illustrated in the figures, a first sump outlet 138 is in fluid communication with a fluid supply conduit connected to the middle spray arm 122, a second sump outlet 140 is in fluid communication with a fluid supply conduit connected to the top spray device 120, a third sump outlet 142 is in fluid communication with a fluid supply conduit connected to the lower spray arm 124.

Therefore, in the exemplary embodiment, first sump outlet 138 is configured to provide washing fluid from sump 114 to middle spray arm 122, the second sump outlet 140 is configured to provide washing fluid from sump 114 to top spray device 120, and third sump outlet 142 is configured to provide washing fluid from sump 114 to lower spray arm 124. In other embodiments, sump outlets 138, 140, 142 may enable the supply of washing fluid from sump 114 to any of spray arms/devices 120, 122, 124 and/or any other component of the washing fluid conduit system 118 of the dishwasher 100.

According to an embodiment of the present invention, the sump outlets are spaced in a manner required to function in combination with the flow controller 150 described hereinbelow to selectively supply washing fluid to the corresponding washing fluid conduits.

In the exemplary embodiment of the invention, a first extra sump outlet 144 and second extra sump outlet 146 are further provided that may enable washing fluid to be supplied from sump 114 to a variety of components of the dishwasher 100.

For example, the first extra sump outlet 144 and/or the second extra sump outlet may provide washing fluid from sump 114 to a component of dishwasher 100 outside of dishwashing chamber 103 of tub 106 and/or may provide washing fluid from sump 114 to, for example any of: a detergent dispenser (e.g., included within the door 112 of the dishwasher 100, shown in Figure 1) for diluting the detergent before dispensing into the chamber 103, the filter unit of the sump 114, an extra tank spaced from sump 114 and arranged outside the sump (e.g., to hold fresh water/washing fluid and/or cleaned and filtered washing fluid/water to be used at a later time during a dishwashing cycle), a heat exchanger for exchanging warm water/washing fluid with fresh water/washing fluid for rinsing dishes within the dishwasher or heat exchanger for exchanging refrigerant fluid of a heat pump system with water, a specific rotating/fixed washing fluid spray device configured to spray washing fluid in a specific direction according to user preferences, and any other suitable component of the dishwasher.

It is pointed out that the concepts of the present invention may be applied to cases in which a different number of sump outlets and/or extra sump outlets may be provided, such as for example when no extra sump outlet is provided.

According to an embodiment of the present invention, the flow controller assembly 150 comprises a flow diverter 152 element having the shape of a plate comprising a plurality of diverter apertures 153 (see Figure 3). In the exemplary embodiment of the invention illustrated in the figures, the flow diverter 152 has four diverter apertures 153, however a different number of diverter apertures 153 may be contemplated. In the exemplary embodiment of the invention illustrated in the figures, the flow diverter 152 has the shape of a disk. However, similar considerations apply in case the flow diverter 152 has a different discoidal shape, such as for example if the flow diverter is a polygonal plate. According to an embodiment of the present invention, the flow diverter 152 is configured to be received into a corresponding receiving portion 148 of the sump 114 that is in fluid communication with the sump outlets 138, 140, 142 and extra sump outlets 144, 146 (if present).

According to an embodiment of the present invention, the flow controller housing 136 fits around or envelops the flow diverter 152 at the housing opening 155 when the flow diverter 152 is positioned within the receiving portion 148 of the sump 114. In use, the flow diverter 152 is located between the flow controller housing 136 and the sump 114.

According to an embodiment of the present invention, the flow controller assembly 150 comprises a positioning system configured to rotate the flow diverter 152 relative to the sump outlets 138, 140, 142, 144, 146.

According to an embodiment of the present invention, the positioning system of the flow controller assembly 150 comprises a motor 156 configured to rotate the flow diverter 152 about its rotation axis, identified in Figure 3 with reference R. According to an embodiment of the present invention, the motor 156 is configured to rotate the flow diverter 152 at a constant rotation speed when driven by the control unit 125.

According to an embodiment of the present invention, the positioning system of the flow controller assembly 150 is configured to rotate the flow diverter 152 across a plurality of predetermined operative diverter positions Ti (i = 1, 2, ...), with each predetermined diverter position Pi that provides for the alignment between one or more diverter apertures 153 and one or more respective sump outlets among the available sump outlets 138, 140, 142, 144, 146, thereby enabling washing fluid received in the volume of the flow controller housing 136 by the pump 116 flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit.

According to an embodiment of the present invention, the positioning system of the flow controller assembly 150 is also configured to rotate the flow diverter 152 to a closure diverter position CP that does not provide any alignment between diverter apertures 153 and sump outlets, thereby preventing washing fluid flow through any sump outlet.

According to an embodiment of the present invention, each predetermined diverter position Ti and the closure diverter position CP corresponds to a respective angular position of the flow diverter 152.

According to an embodiment of the present invention, the positioning system of the flow controller assembly 150 comprises a control unit that is configured to drive the motor 156 in order to rotate the flow diverter 152 to a target one among the predetermined diverter positions Ti based on the (phase of the) washing cycle being carried out by the dishwasher 100.

In the exemplary embodiment of the invention herein considered, the control unit of the positioning system of the flow controller assembly 150 is the control unit 125 configured to control the operation of the dishwasher 100. However, similar considerations apply in case the control unit of the positioning system is a dedicated control unit different from the control unit 125.

According to an embodiment of the present invention, and as will be described in detail hereinbelow, the positioning system of the flow controller assembly 150 is configured to assess a current position of the flow diverter 152 among the predetermined diverter positions Ti (and optionally, also the closure diverter position CP). According to an embodiment of the invention, the positioning system of the flow controller assembly 150 comprises a cam support element 154 coaxially coupled to the flow diverter 152 between the flow diverter 152 itself and the motor 156 (see Figure 3) and comprising a plurality of protruding cam elements.

Detailed views of the cam support element 154 according to an embodiment of the invention when are shown in Figures 4A and 4B. More particularly, Figure 4A is a perspective view from above of the cam support element 154, and Figure 4B is a perspective view from below of the cam support element 154.

According to an embodiment of the present invention, the cam support element 154 comprises a substantially flat body, such as a disk-shaped body, having a top surface 160 facing the flow diverter 152 and a bottom surface 162 opposite the top surface 160.

According to an embodiment of the present invention, the cam support element 154 is configured to be coupled to the flow diverter 152 by means of a shaft member 164 protruding upward from the centre of the top surface 160 and configured to be engaged into a corresponding hole provided on the flow diverter 152 at the rotation axis R thereof.

According to an embodiment of the present invention, the cam support element 154 is configured to be coupled to a driveshaft of the motor 156 (see Figure 3) through a receiving hole 166 located at the centre of the bottom surface 162 configured to receive the driveshaft of the motor 156.

In this way, since the flow diverter 152 and the cam support element 154 are coupled to each other, they rotate together when the motor 156 is on.

According to an embodiment of the present invention, the cam support element 154 comprises a plurality of cam elements C(i) located at the peripheral portion of the bottom surface 162 and protruding from the latter surface toward the motor 156 (see Figure 4B). The concepts of the present invention can be directly applied to cases in which the cam elements C(i) are located in a different portion of the cam support element 154, such as for example along a portion of the bottom surface 162 corresponding to a circle having a centre at the receiving hole 166 and a radius lower than the radius of the disk-shaped body, or to the cases in which the cam elements C(i) protrude toward a different direction, such as for example perpendicularly to the rotation axis R.

According to an embodiment of the present invention, each cam element C(i) of the plurality of cam elements C(i) is associated with a corresponding predetermined diverter position Ti. In the exemplary embodiment of the invention illustrated in the figures, the plurality of cam elements C(i) comprises eight cam elements C(l), C(2), C(8), each one associated with a corresponding one among eight predetermined diverter positions Tl, 1'2. ..., T8. A different number of cam elements C(i) may be contemplated.

According to an embodiment of the present invention, each cam element C(i) extends along a corresponding arc of the cam support element 154. Therefore, since the flow diverter 152 and the cam support element 154 are coaxially coupled to each other, each cam element C(i) also extends along a corresponding arc of the flow diverter 152.

As visible in Figure 4B, according to an embodiment of the present invention, each cam element C(i) is shaped so as to comprise a slanted portion and a flat portion. However, similar considerations apply to cases in which the cam elements C(i) have a different shape.

According to an embodiment of the present invention, the plurality of cam elements C(i) comprises a reference cam element having an arc length different from the arc lengths of the other cam elements C(i) of the plurality. In the example illustrated in the figures, the reference cam element is the cam element C(l) corresponding to the predetermined diverter position Tl.

According to an embodiment of the present invention, the reference cam element has an arc length that is longer than the arc length of the other cam elements. According to another embodiment of the present invention, the reference cam element has an arc length that is shorter than the arc length of the other cam elements. In the example illustrated in the figures, the reference cam element C(l) has an arc length that is longer than the arc length of the other cam elements C(i) (i= 2 to 8).

According to an embodiment of the present invention, the cam elements C(i) different from the reference cam element have all a same length, which is different from (/'.<?., longer or shorter than) the length of the reference cam element. According to another embodiment of the present invention, some (e.g., each) of the cam elements C(i) different from the reference cam element may have lengths that are shorter or longer than the lengths of the other cam elements C(i) different from the reference cam element (in any case, the reference cam element has a length that is longer or shorter than all the cam elements different from the reference cam element). In the example illustrated in the figures, the reference cam element C(l) has an arc length that is longer than the arc length of the other cam elements C(i) (i = 2 to 8), and all the cam elements C(i) (i = 2 to 8) different from the reference cam element C(l) have a same length. According to an embodiment of the present invention, the positioning system of the flow controller assembly 150 further comprises a cam follower system 180 located under the cam support element 154 (see Figure 3) and configured to mechanically interact with the cam elements C(i) of the cam support element 154.

Figure 5 is a more detailed perspective view of the cam support element 154 and of portions of the cam follower system 180 according to an embodiment of the present invention.

According to an embodiment of the present invention, the cam follower system 180 comprises a cam follower element 182 configured to mechanically interact with the cam elements C(i) of the cam support element 154.

According to an embodiment of the present invention, the cam follower system 180 comprises a detection switch 184 configured to mechanically interact with the cam follower element 182. According to an embodiment of the present invention, the detection switch 184 is configured to commute to a first state SI when the cam follower element 182 is mechanically interacting with a cam element C(i) and to commute to a second state S2 when the cam follower element 182 is not mechanically interacting with a cam element C(i).

According to an exemplary embodiment of the present invention, the cam follower system 180 comprises a biasing system, for example comprising one or more springs, configured to bias the cam follower element 182 toward the (bottom surface 162 of the) cam support element 154. When the angular position of the cam follower element 182 is such that a cam element C(i) mechanically interacts with the cam follower element 182, the protruding cam element C(i) pushes the cam follower element 182 against the bias exerted by the biasing system, causing the detection switch 184 to commute to the first state SI. When the angular position of the cam follower element 182 is such that no cam element C(i) mechanically interacts with the cam follower element 182, the cam follower element 182 is pushed toward the (bottom surface 162 of the) cam support element 154 by the biasing system, causing the detection switch 184 to commute to the second state S2.

In this way, during the rotation of the flow diverter 152 - and therefore, of the cam support element 154 - the detection switch 184 commutes between the first and second states SI, S2. Particularly, every time a cam element C(i) passes at (e.g., above) the location of the detection switch 184, the detection switch 184 commutes from the second state S2 to the first state SI. Then, as long as the cam element C(i) is located at (e.g., above) the location of the detection switch 184, the detection switch 184 stays at the first state SI. Once the cam element C(i) leaves the position at (e.g., above) the location of the detection switch 184, the detection switch 184 commutes back from the first state SI to the second state S2. The detection switch 184 stays at the second state S2 until the rotation of the flow diverter 152 - and therefore, of the cam support element 154 - causes a new cam element C(i) pass at (e.g., above) the location of the detection switch 184. When this latter condition is verified, the detection switch 184 commutes from the second state S2 to the first state SI .

It is pointed out that although in the illustrated embodiment of the invention reference has been made to a cam support element 154 in which each cam element C(i) protrudes from the bottom surface 162 of the cam support element 154 toward the motor 156 along a direction substantially parallel to the rotation axis R, and the cam follower element 182 is configured to move along said direction substantially parallel to the rotation axis R, similar considerations apply in case the cam elements C(i) protrude from the cam support element 154 along a different direction, such as substantially perpendicularly to the rotation axis R, and the cam follower element 182 is configured to move along said different direction substantial perpendicular to the rotation axis R.

According to another embodiment of the present invention, no cam support element 154 is provided, and the cam elements C(i) are directly provided on the flow diverter 152, such as on the bottom surface of the flow diverter 152.

According to an embodiment of the present invention, the cam follower system 180 further comprises the control unit of the positioning system of the flow controller assembly 150 configured to assess the current position of the flow diverter 152 among the predetermined diverter positions Ti and to drive the motor 156 according to the assessed position. According to another embodiment of the present invention, the cam follower system 180 comprises a dedicated control unit different from the one of the positioning system of the flow controller assembly 150.

Since according to the embodiments of the present invention the arc length of the reference cam element C(l) is different from the arch lengths of the other cam elements C(i), it is advantageously possible to assess when the current rotational position of the flow diverter 152 corresponds to a reference diverter position Tl (among the predetermined diverter positions Ti) corresponding to the reference cam element C(l) by observing the evolution over time of the state of the detection switch 184

Particularly, according to an embodiment of the present invention, the control unit 125 is configured to assess a position of the flow diverter 152 corresponding to the reference diverter position T1 based on durations of interaction intervals II during which the detection switch 184 stays at the first state SI.

According to the embodiments of the invention in which the reference cam element C(l) has an arc length that is longer than the arc lengths of the other cam elements C(i) (like the one illustrated in the figures), the control unit 125 is configured to assess a position of the flow diverter 152 corresponding to the reference diverter position T1 when an interaction interval II having a duration that is longer than the durations of the other interaction intervals II is detected.

According to the (not illustrated) embodiments of the invention in which the reference cam element C(l) has an arc length that is shorter than the arc lengths of the other cam elements C(i), the control unit 125 is configured to assess a position of the flow diverter 152 corresponding to the reference diverter position T1 when an interaction interval II having a duration that is shorter than the durations of the other interaction intervals II is detected.

Figure 6 illustrates an evolution over time 600 of the state of the detection switch 184 according to an exemplary embodiment of the invention during a rotation of the flow diverter 152 at a constant rotation speed when eight cam elements C(i) are provided (i = 1 to 8), and the reference cam element C(l) has a first arc length while the other cam elements C(i) (i = 2 to 8) have all a same second arch length lower than the first arc length (like in the exemplary embodiments of the invention illustrated in Figures 4A and 4B).

In the considered example, each complete revolution of the flow diverter 152 about the rotation axis R, identified in Figure 6 with reference 605 provides for a sequence of eight interaction intervals II(i) (i = 1 to 8) during which the detection switch 184 is maintained at the first state SI, each one corresponding to a respective one of the cam elements C(i).

As depicted in Figure 6, there is an interaction interval 11(1) that has a duration that is longer than the duration of each one of the other interaction intervals II(i). This interaction interval 11(1) corresponds to the reference diverter position Tl, since the longer arc length of the corresponding reference cam C(l) results in a longer time of the detection switch 184 at the state SI (since the rotational speed of the flow diverter 152 is constant).

According to an embodiment of the present invention, the control unit 125 is configured to assess a position of the flow diverter 152 corresponding to one of the predetermined diverter positions Ti different from the reference diverter position Tl by counting a number of times the detection switch 184 is commuted to a selected one between the first state SI and the second state S2 after the assessment of the reference diverter position Tl. According to an embodiment of the present invention, the control unit 125 is configured to store, for example in an electronic memory comprised in or coupled to the control unit 125, a position counter PI indicative of the actual (angular) position of the flow diverter 152 among the predetermined diverter positions Ti.

According to an embodiment of the present invention, the control unit 125 is configured to set the position counter PI to a first value (in the considered exemplary embodiment of the invention, PI = 1) upon the assessment that the flow diverter 125 has reached an angular position corresponding to the reference diverter position Tl. In the considered exemplary embodiment of the invention, when the position counter PI is equal to 1 it means that the flow diverter 152 is at an angular position corresponding to the reference diverter position Tl.

According to an embodiment of the present invention, the control unit 125 is configured to update the value of the position counter PI (in the considered exemplary embodiment of the invention, by increasing PI by one) each time the detection switch 184 is commuted to the first state SI after the assessment of the reference diverter position Tl. According to another embodiment of the present invention, the control unit 125 is configured to update the value of the position counter PI each time the detection switch 184 is commuted to the second state S2 after the assessment of the reference diverter position Tl. In the considered exemplary embodiment of the invention, when the position counter PI is equal to z (z > 1) it means that the flow diverter 152 is at an angular position corresponding to the predetermined diverter position Ti.

According to an embodiment of the present invention, the control unit 125 is configured to set the value of the position counter PI to a null value (in the considered exemplary embodiment of the invention, PI = 0) indicative of an unknown position of the flow diverter 152 when the control unit 125 is not (e.g., yet) capable of assessing the current position of the flow diverter 152.

By making reference to the time diagram of the non-limitative example illustrated in Figure 6, it is assumed that the initial angular position of the flow diverter 152 before the flow diverter 152 is driven to rotate is between the predetermined diverter positions T6 and T7, but the control unit 125 is not aware of this position, and therefore the position counter PI is set to the null value 0. In this exemplary initial configuration, the detection switch 184 is at the second state S2.

Once the motor 156 is activated and the flow diverter 152 starts to rotate, the detection switch 184 switches to the first state SI when the cam follower element 182 is pushed by the cam element C(7). Since the cam element C(7) is not the reference cam element C(l), the detection switch 184 remains at the first state SI for a relatively short interaction interval 11(7), returning then to the second state S2. Moreover, since the position counter PI is at the null value 0, the control unit 125 still does not have sufficient information to assess the current angular position of the flow diverter 152. The position counter PI is therefore kept at the null value 0.

Afterwards, the detection switch 184 switches to the first state SI when the cam follower element 182 is pushed by the cam element C(8). Since the cam element C(8) is not the reference cam element C(l), the detection switch 184 remains at the first state SI for a relatively short interaction interval 11(8), returning then to the second state S2. Moreover, since the position counter PI is at the null value 0, the control unit 125 still does not have sufficient information to assess the current angular position of the flow diverter 152. The position counter PI is therefore kept at the null value 0.

Afterwards, the detection switch 184 switches to the first state SI when the cam follower element 182 is pushed by the cam element C(l). Since the cam element C(l) is the reference cam element, the detection switch 184 remains at the first state SI for a relatively long interaction interval 11(1), and the control unit 125 assesses that the current angular position of the flow diverter 152 corresponds to the reference diverter position T1 and sets the position counter PI to 1. Then, at the end of the interaction interval 11(1), the detection switch 184 returns to the second state S2.

Afterwards, the detection switch 184 switches to the first state SI when the cam follower element 182 is pushed by the cam element C(2). Since the cam element C(2) is not the reference cam element C(l), the detection switch 184 remains at the first state SI for a relatively short interaction interval 11(8), returning then to the second state S2. Moreover, since the position counter PI is at a value different from the null value 0 (z.e., 1), the control unit 125 increases the position counter PI by 1, z.e., PI = 1+1 = 2. In this way, since the position counter PI is equal to z = 2, the control unit 125 determines that the current angular position of the flow diverter 152 corresponds to the predetermined reference position Ti = 7'2.

The procedure is reiterated by increasing the position counter PI by 1 every time the detection switch 184 switches to the first state SI, and determining that the current angular position of the flow diverter 152 corresponds to the predetermined reference position is equal to Ti, where z is the value of the increased position counter PI.

When the cam follower element 182 mechanically interacts again with the cam element C(l) after the flow diverter 152 has made a complete revolution, the detection switch 184 remains at the first state SI for a relatively long interaction interval 11(1). In this situation, the control unit 125 assesses that the current angular position of the flow diverter 152 corresponds to the reference diverter position Tl, and sets the position counter PI to 1.

In other words, according to an embodiment of the present invention, and starting from a condition in which the current position of the flow diverter 152 is unknown (PI = 0), the control unit 125 is configured to carry out a first phase directed to assess when the angular position of the flow diverter 152 reaches the reference diverter position Tl. Then, once the flow diverter 152 has been assessed to be at the reference diverter position Tl, this information is used by the control unit 152 in a subsequent second phase as a reference to assess when the angular position of the flow diverter 152 reaches the following predetermined diverter positions T2, T3, T4, ...

In this way, by exploiting the reference diverter position Tl as a reference, it is advantageously possible to efficiently drive a flow diverter 152 across a substantially large number of different predetermined diverter positions Ti without having to use for each predetermined diverter positions Ti a corresponding cam element having a different arc length. Indeed, according to the embodiments of the present invention, it is in principle sufficient to provide cam elements C(i) having two different arc lengths only (one for the reference cam element and one for the other cam elements) so as to be capable of distinguishing the reference cam element from the other cam elements. Tolerance problems due to excessively similar cam elements (in terms of arc lengths) are therefore advantageously avoided even in presence of a large number of predetermined diverter positions (and therefore in presence of a large number of cam elements).

It is pointed out that although in the exemplary embodiment of the invention described with reference to Figure 6 the position counter PI is increased - starting from a reference value, such as 1 - every time a commutation of the detection switch 184 from the second state S2 to the first state SI is detected, similar considerations apply if the position counter PI is decreased - starting from a reference value, such as 8 - every time a commutation of the detection switch 184 from the second state S2 to the first state SI is detected.

According to an embodiment of the present invention, the control unit 125 is configured to receive an indication TP of a target (angular) position - among the predetermined diverter positions Ti - the flow diverter 152 has to reach based on the (phase of the) washing cycle being carried out by the dishwasher 100. According to an embodiment of the present invention the control unit 125 is configured to stop the motor 156 once the position counter PI matches (e.g., is equal to) the target position indication TP, so as to keep the flow diverter 152 at the desired target position in order to enable washing fluid received in the volume of the flow controller housing 136 flows to washing fluid supply conduits of the washing fluid conduit system 118 (see Figures 1 and 3) selected through the flow diverter 152.

Figures 7A - 7B illustrate a flow chart of main operations carried out by the control unit 125 of the positioning system of the flow controller assembly 150 for assessing the position of the flow diverter 152 according to an embodiment of the present invention.

According to an embodiment of the present invention, at the power on of the dishwasher 100, the position counter PI and the target position indication TP are set to the null value (e.g., 0) (block 702).

According to an embodiment of the present invention, the control unit 125 checks the state of the detection switch 184 (block 704). If the detection switch 184 is in the first state SI (exit branch Y of block 704), meaning that the angular position of the flow diverter 152 is such that one of the cam elements C(i) is pushing the cam follower element 182, the control unit 125 turns on the motor 156 to rotate the flow diverter 152 until the detection switch 184 commutes to the second state S2, i.e., until the cam follower element 182 disengages from the cam C(i) (block 706). According to an embodiment of the present invention, the control unit 125 may be further configured to generate a warning indicating that there is a malfunctioning in the positioning system of the flow controller assembly 150, such as for example a malfunctioning in the motor 156 and/or in the cam follower system 180, if the detection switch 184 does not commute to the second state S2 within a corresponding timeout interval.

According to an embodiment of the present invention, once the detection switch 184 commutes to the second state S2 or if the the detection switch 184 was already in the second state S2 at the power on of the dishwasher (exit branch N of bloc 704), the control unit 125 enters a waiting loop to wait for the reception of a (new) target position indication TP (block 708 and exit branch N thereof, returning to the same block 708).

According to an embodiment of the present invention, when a target position indication TP is received by the control unit 125 (exit branch Y of block 708), for example because a new phase of the washing cycle to be carried out by the dishwasher 100 requires a corresponding new positioning of the flow diverter 152, the control unit 125 turns on the motor 156 to enable the rotation of the flow diverter 152 and starts a timer TM (block 710).

According to an embodiment of the present invention, if the timer TM expires before the detection switch 184 switches to the first state SI (exit branch N of block 712) the control unit 125 generates a warning (block 714, return to block 708) indicating that there is a malfunctioning in the positioning system of the flow controller assembly 150, such as for example a malfunctioning in the motor 156 and/or in the cam follower system 180.

According to an embodiment of the present invention, if the control unit 125 assesses that the detection switch 184 commutes to the first state SI before the timer TM expires (exit branch Y of block 712), it means that the positioning system of the flow controller assembly 150 is correctly operating, since the flow diverter 152 is actually rotating and the rotation is detected by the commutation of the detection switch 184 caused by the mechanical interaction of a cam element C(i) of the rotating flow diverter 152 with the cam follower element 182.

Then, according to an embodiment of the present invention, the control unit 125 measures a duration D(i) of the interaction interval II (i) during which the detection switch 184 is maintained at the first state SI by the cam element C(i) (block 720). According to an embodiment of the present invention, the duration D(i) is calculated by the control unit 125 based on a timer started when the detection switch 184 commutes to the first state SI (e.g., at exit branch Y of block 712) and stopped when the detection switch 184 commutes to the second state S2.

According to an embodiment of the present invention, the control unit 125 compares the measured duration D(i) of the interaction interval II(i) with a short cam limit threshold SCL indicative of a maximum limit of duration and a long cam limit threshold LCL (block 730). According to an embodiment of the present invention, the short cam limit threshold SCL is set to a value corresponding to (e.g., just higher than) the maximum expected duration of an interaction interval II(i) associated with one of the (“short”) cam elements C(i) different from the reference cam element C(i). According to an embodiment of the present invention, the long cam limit threshold LCL is set to a value corresponding to (e.g., just higher than) the maximum expected duration of the interaction interval 11(1) associated with the (“long”) reference cam element C(l). According to an embodiment of the present invention, the long cam limit threshold LCL is higher than the short cam limit threshold SCL.

According to an embodiment of the present invention, if the measured duration D(i) of the interaction interval II(i) is longer than the short cam limit threshold SCL and at the same time is shorter than the long cam limit threshold LCL (exit branch Y of block 730) it means that the cam element C(i) which caused the commutation of the detection switch 184 is the reference cam element C(l). In this situation, according to an embodiment of the present invention, the control unit 125 sets the position counter PI to 1, to indicate that the flow diverter 152 has been assessed to be in the reference diverter position Tl.

According to an embodiment of the present invention, if the measured duration D(i) of the interaction interval II(i) is shorter than the short cam limit threshold SCL and at the same time is longer than a minimum threshold MINL set to a value sufficiently large to filter out unwanted glitches and noises affecting the measurement operations (exit branch Y of block 740) it means that the cam element C(i) which caused the commutation of the detection switch 184 is one of the cam elements C(i) different from the reference cam element C(l). In this situation, according to an embodiment of the present invention, the control unit 125 checks the current value of the position counter PI (block 742). If the position counter PI is still at the null value 0 (exit branch Y of block 742), the control unit 125 does not have sufficient information to assess the current angular position of the flow diverter 152 (since the reference diverter position Tl has not identified yet) and therefore the control unit 125 keeps the motor 156 active, so as to allow a further rotation of the flow diverter 152. In this case, the flow of operation returns back to block 710, to wait for the next commutation of the detection switch 184 to the first state SI caused by the next cam element C(i). If instead the position counter PI is different from 0 (exit branch N of block 742), the control unit 152 increments the current value of the position counter PI by 1 (block 745) to indicate that the flow diverter 152 has been assessed to be in the predetermined diverter position Ti. with z that is equal to the current value of the position counter PI. According to an embodiment of the present invention, the minimum threshold MINL is lower than the short cam limit threshold SCL.

According to an embodiment of the present invention, if the measured duration D(i) of the interaction interval II(i) is longer than the short cam limit threshold SCL or shorter than the minimum threshold MINL (exit branch N of block 740) the control unit 125 sets the position counter PI to the null value 0 to indicate that the current position of the flow diverter 152 is unknown since this interaction interval II(i) cannot be identified to be associated to any of the cam elements C(i) (block 750).

According to an embodiment of the present invention, once the value of the position counter PI is updated (blocks 735, 745 or 750), the control unit 125 compares the current value of the position counter PI with the target position indication TP (block 760).

According to an embodiment of the present invention, if the current value of the position counter PI is equal to the target position indication TP (exit branch Y of block 760), the control unit 125 turns off the motor 156 (block 755), so as the rotation of the flow diverter 152 is stopped in the requested position indicated by the target position indicator TP (return to block 708).

According to an embodiment of the present invention, if the current value of the position counter PI is (still) not equal to the target position indication TP (exit branch N of block 760), the control unit 125 keeps the motor 156 active, so as to allow a further rotation of the flow diverter 152. In this case, the flow of operation returns back to block 710, to wait for the next commutation of the detection switch 184 to the first state SI caused by the next cam element C(i).

Figure 8 illustrates a non-limitative example of circuit elements of (a portion of) the positioning system of the flow controller assembly 150 according to an exemplary embodiment of the present invention.

According to an embodiment of the present invention, the positioning system of the flow controller assembly 150 further comprises a driver module 810 configured to drive the motor 156 through a motor driving signal MDS generated based on control signals CS provided by the control unit 125.

According to an embodiment of the present invention, the control signals CS generated by the control unit 125 comprise two Pulse Width Modulated (PWM) control signals CS that are offset in phase, such as by 180°. According to an embodiment of the present invention, the control signals CS have a duty cycle lower than or equal to 50%, such as for example equal to 45%.

According to an embodiment of the present invention, the driver module 810 comprises an H-bridge circuit configured to receive the control signals CS and accordingly generate a (differential) motor driving signal MDS to be provided across two electric terminals of the motor 156.

According to an embodiment of the present invention, the detection switch 184 comprises a first electric terminal electrically coupled to one of the two electric terminals of the motor 156 and a second electric terminal electrically coupled to an input terminal of the control unit 125 for providing a sensing signal SS indicative of the state of the detection switch 184. According to an embodiment of the present invention, when the detection switch 184 is in the first state SI, the first electric terminal of the detection switch 184 is electrically coupled to the second electric terminal of the detection switch 184. According to an embodiment of the present invention, when the detection switch 184 is in the second state S2, the first electric terminal of the detection switch 184 is electrically decoupled from the second electric terminal of the detection switch 184.

According to an embodiment of the present invention, the control unit 125 is electrically supplied by a DC supply voltage VS1 (for example, <+20 V, such as +5 V) and the driver module 810 is electrically supplied by a DC supply voltage VS2 (for example, <+20 V, such as +12 V). According to an embodiment of the present invention, the motor 156 is an AC motor, such as for example a 12 V AC motor.

According to an embodiment of the present invention, the DC supply voltages VS1 and VS2 are generated by a voltage supply unit 820 connected to the mains.

According to an embodiment of the present invention, the second electric terminal of the detection switch 184 is electrically coupled to the input terminal of the control unit 125 through a conditioning network comprising a voltage divider 830 and a pull-up element 840.

According to an embodiment of the present invention, when the detection switch 184 is in the first state SI because the cam follower element 182 is mechanically interacting with a cam element C(i), the first electric terminal of the detection switch 184 is electrically coupled to the second electric terminal of the detection switch 184, and the sensing signal SS provided to the input terminal of the control unit 125 is an oscillating signal whose amplitude depends on the voltage divider 830.

According to an embodiment of the present invention, when the detection switch 184 is in the second state SI because the cam follower element 182 is not mechanically interacting with any cam element C(i), the first electric terminal of the detection switch 184 is electrically decoupled from the second electric terminal of the detection switch 184, and the sensing signal SS provided to the input terminal of the control unit 125 is clamped to a fixed voltage (e.g., the DC supply voltage VS1) by the pull-up element 840.

Since in the architecture shown in Figure 8 the voltages managed by the control unit 125, the driver module 810 and the motor 156 are “low” voltages, i.e., <+20 V, Class I plastic may be advantageously used to implement elements of the flow controller assembly 150, and/or a low voltage AC motor may be advantageously used to implement the motor 156.

Claims

1. A dishwasher comprising:

- a washing fluid conduit system comprising a plurality of washing fluid supply conduits each one for supplying washing fluid to at least one corresponding component of the dishwasher;

- a sump for collecting washing fluid, the sump comprising a plurality of sump outlets each one for a corresponding washing fluid supply conduit of the plurality;

- a pump for pumping washing fluid from the sump to the washing fluid conduit system;

- a flow controller assembly operable for selectively enabling washing fluid flow from the sump to selected one or more washing fluid supply conduits, the flow controller assembly comprising:

- a discoidal flow diverter comprising a plurality of diverter apertures;

- a positioning system configured to rotate the flow diverter relative to the sump outlets across a plurality of predetermined diverter positions, each diverter position providing for the alignment between one or more diverter apertures and one or more respective sump outlets, thereby enabling washing fluid flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit, wherein the positioning system comprises:

- a plurality of cam elements coupled to the flow diverter, each cam element being associated with a corresponding predetermined diverter position, each cam element extending along a corresponding arc of the flow diverter, said plurality of cam elements comprising a reference cam element having an arc length different from the arc lengths of the other cam elements of the plurality;

- a motor configured to rotate the flow diverter;

- a cam follower system comprising a cam follower element configured to mechanically interact with the cam elements and interact with a detection switch so as to commute the detection switch to a first state when the cam follower element is mechanically interacting with a cam element and to commute the detection switch to a second state when the cam follower element is not mechanically interacting with a cam element;

- a control unit configured to assess a position of the flow diverter among the predetermined diverter positions and to drive the motor according to the assessed position, wherein the control unit is configured to assess said position of the flow diverter by:

2. The dishwasher of claim 1, wherein the control unit is configured to store a counter indicative of the position of the flow diverter among the predetermined diverter positions, the control unit being configured to set the counter to a first value upon the assessment that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position.

3. The dishwasher of claim 2, wherein the control unit is configured to update the value of the counter each time the detection switch is commuted to the selected state after the assessment of the reference predetermined diverter position.

4. The dishwasher of any of the preceding claims, wherein each cam element of the plurality that is different from the reference cam element has an arc length that is lower than an arc length of the reference cam element.

5. The dishwasher of claim 4, wherein the control unit is configured to assess that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration higher than a first threshold.

6. The dishwasher of claim 5, wherein the control unit is configured to assess that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration that is both:

- higher than said first threshold, and

7. The dishwasher of claim 6, wherein the control unit is configured to generate a warning indicative of an invalid position of the flow diverter upon the assessment of at least one between:

- an interaction interval having a duration higher than said second threshold,

8. The dishwasher of claim 6 or of claim 7, wherein said second threshold has a value depending on the arc length of the reference cam element.

9. The dishwasher of any of claims 5 to 8, wherein said first threshold has a value depending on the arc lengths of the cam elements of the plurality that are different from the reference cam element.

10. The dishwasher of any of the preceding claims, wherein the cam elements of the plurality different from the reference cam element have all a same arc length.

11. The dishwasher of any of the preceding claims, wherein the motor is configured to rotate the flow diverter at a constant rotation speed when driven by the control unit.

12. The dishwasher of any of the preceding claims, wherein each cam element protrudes parallel to a rotation axis of the flow diverter.

13. The dishwasher of any of the preceding claims, wherein the control unit is configured to generate a malfunctioning warning indicative of a malfunctioning of the motor and/or of the cam follower system if a timeout expires before the assessment of a new commutation of the detection switch following a turning on of the motor.

14. The dishwasher of any of the preceding claims, wherein the control unit is configured to:

- receive an indication of a target one among the predetermined diverter positions;

- drive the motor to rotate the flow diverter until the flow diverter has been assessed to reach an angular position corresponding to said target predetermined flow diverter position.

15. The dishwasher of claim 14, wherein the control unit is configured to: - turn off the motor when the flow diverter has been assessed to reach an angular position corresponding to said target predetermined diverter position;

- turn on the pump, thereby causing washing fluid flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit.

16. The dishwasher of claim 14 or 15, wherein said indication of a target one among the predetermined diverter positions depends on a phase of a selected washing cycle being performed by the dishwasher.

17. The dishwasher of any of the preceding claims, wherein the control unit is configured to carry out the following operation at the power on of the dishwasher:

18. The dishwasher of any of the preceding claims, wherein the positioning system further comprises a driver module configured to:

- providing motor driving signals to terminals of the motor, wherein:

- the detection switch comprises a first electric terminal electrically coupled to a terminal of the motor and a second electric terminal electrically coupled to an input of the control unit for providing a sensing signal indicative of the state of the detection switch.

19. The dishwasher of claim 18, wherein:

-when the detection switch is in the first state, the first electric terminal is electric coupled to the second electric terminal;

- when the detection switch is in the second state, the first electric terminal is electrically decoupled from the second electric terminal.

20. The dishwasher of claim 18 or 19, wherein the driver module and the control unit are electrically supplied by DC supply voltages.

21. The dishwasher of claim 20, wherein said DC supply voltages are lower than 20 Volts.

22. The dishwasher of any of the preceding claims, wherein the positioning system further comprises a cam support element coaxially coupled to the flow diverter, said cam elements being located on said cam support element.

23. The dishwasher of any of the preceding claims, wherein said components of the dishwasher comprise at least one among:

- a dishwasher spray arm;

- a dishwasher detergent dispenser;

- a filter of the sump;

- a dishwasher reservoir tank;

- a dishwasher heat exchanger.

24. A method for operating a dishwasher comprising:

- selectively enabling washing fluid flow from a dishwasher sump to selected one or more washing fluid supply conduits of a dishwasher washing fluid conduit system, said selectively enabling comprising:

- rotating a discoidal flow diverter relative to sump outlets of the sump across a plurality of predetermined diverter positions, each sump outlet corresponding to a corresponding washing fluid supply conduit, each diverter position providing for the alignment between one or more diverter apertures on the flow diverter and one or more respective sump outlets, thereby enabling washing fluid flow from each one of said one or more sump outlets aligned with said one or more diverter apertures to the corresponding washing fluid supply conduit, wherein a plurality of cam elements is coupled to the flow diverter, each cam element being associated with a corresponding predetermined diverter position, each cam element extending along a corresponding arc of the flow diverter, said plurality of cam elements comprising a reference cam element having an arc length different from the arc lengths of the other cam elements of the plurality;

- assessing a position of the flow diverter among the predetermined diverter positions through a cam follower system comprising a cam follower element configured to mechanically interact with the cam elements and interact with a detection switch so as to commute the detection switch to a first state when the cam follower element is mechanically interacting with a cam element and to commute the detection switch to a second state when the cam follower element is not mechanically interacting with a cam element, said assessing said position of the flow diverter comprising:

- measuring durations of one or more interaction intervals during which the detection switch is in the first state;

- assessing a position corresponding to a reference one of the predetermined diverter positions associated with the reference cam element based on said measured durations of said one or more interaction intervals;

- counting a number of times the detection switch is commuted to a selected state between the first state and the second state after the assessment of the reference diverter position, and

- assessing a position corresponding to one of the predetermined diverter positions different from the reference diverter position based on said counted a number of times.

25. The method of claim 24, further comprising:

- setting a counter, indicative of the position of the flow diverter among the predetermined diverter positions, to a first value upon the assessment that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position.

26. The method of claim 25, further comprising:

- updating the value of the counter each time the detection switch is commuted to the selected state after the assessment of the reference predetermined diverter position.

27. The method of any on claims 24 to 26, wherein each cam element of the plurality that is different from the reference cam element has an arc length that is lower than an arc length of the reference cam element, the method further comprising:

- assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration higher than a first threshold.

28. The method of claim 27, further comprising:

- assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon the assessment of an interaction interval having a duration that is both: - higher than said first threshold, and

29. The method of claim 28, further comprising:

- generating a warning indicative of an invalid position of the flow diverter upon the assessment of at least one between:

- an interaction interval having a duration higher than said second threshold,