Dishwasher comprising improved flow controller assembly

Abstract

A dishwasher is provided. The dishwasher (100) comprises: a washing fluid conduit system (118) comprising a plurality of washing fluid supply conduits, each washing fluid supply conduit for supplying washing fluid to at least one corresponding component of the dishwasher; a sump (114) for collecting the washing fluid, the sump comprising a plurality of sump outlets (138, 140, 142), each sump outlet for a corresponding washing fluid supply conduit of the plurality of washing fluid supply conduits; a pump (116) for pumping wash fluid from the sump to the wash fluid conduit system; a flow controller assembly operable to selectively enable flow of wash fluid from the sump to selected one or more wash fluid supply conduits. The flow controller assembly includes a flat circular flow diverter (152), the flat circular flow diverter including 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 alignment between one or more diverter apertures and one or more respective sump outlets, thus, washing fluid can flow from each of the one or more sump outlets aligned with the one or more diverter orifices to a 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, the plurality of cam elements comprising a reference cam element C (1), the arc length of the reference cam element is different from that of other cam elements in the plurality of cam elements; a motor (156) configured to rotate the flow diverter; a cam follower system (180) comprising cam follower elements (182) configured to mechanically interact with the cam elements and to interact with a detection switch (184), a detection switch coupled to the cam follower element so as to switch the detection switch to a first state when the cam follower element mechanically interacts with the cam element, and to switch the detection switch to a second state when the cam follower element does not mechanically interact with the cam element; a control unit (125) configured to evaluate a position of the flow diverter among the predetermined diverter positions and to drive the motor in accordance with the evaluated position, the control unit is configured to evaluate said position of the flow diverter by: evaluating a position corresponding to a reference predetermined diverter position associated with the reference cam element of the predetermined diverter positions based on a duration of an interaction interval in which the detection switch is in the first state; and evaluating a position corresponding to a predetermined diverter position different from the reference diverter position among the predetermined diverter positions by counting a number of times the detection switch transitions to a selected state between the first state and the second state after evaluating the reference diverter position.

Description

[0001] BACKGROUND TECHNICAL FIELD

[0002] The present invention relates generally to a dishwasher, and more particularly to a flow controller assembly for controlling the flow of wash fluid from a sump of a dishwasher to a wash fluid conduit system of the dishwasher. BACKGROUND

[0003] In a dishwasher, a flow controller assembly is used to direct wash fluid from the sump to a selected wash fluid supply conduit system. The flow controller assembly is used to supply wash fluid to the interior of the dishwasher in a manner consistent with the selected dishwasher cleaning cycle to properly clean dishes, cookware, pots, pans, and any other items placed in the dishwasher for cleaning. These flow controller assemblies are typically located in the vicinity of the dishwasher sump.

[0004] Patent application US2014 / 0182625 discloses a dishwasher including a passage switch unit that allows wash water pumped by a wash pump to selectively flow to at least one of three wash arms. The passage switch unit includes a rotary plate that controls the flow of wash water when rotated. The rotary plate is positioned between a passage switch unit housing and a sump cover and selectively opens / closes connection faucets of the sump cover. A plurality of switch holes are formed through the rotary plate. When the rotary plate is rotated, the switch holes of the rotary plate move to positions corresponding to at least one of the connection faucets, and wash water in a switch water collecting portion is sprayed from at least one of the plurality of wash arms.

[0005] Patent US 8,915,257 discloses an aqueous household appliance comprising a water diverter having at least one adjustable fluid distribution element, in particular a rotary disc, to which 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 comprises a plurality of passage openings provided on a planar upper surface of the at least one adjustable fluid distribution element and a plurality of entry areas each corresponding to one of the plurality of passage openings.

[0006] US 9980624 discloses a variable position diverter that provides wash fluid to a selected combination of outlet ports and spray assemblies. The diverter includes a housing having a plurality of outlet ports and a valve disc having a plurality of apertures. The valve disc 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

[0007] As highlighted above, the flow controller assembly typically comprises a diverter configured to rotate across a plurality of predetermined positions to selectively align with various taps / fluid lines / outlets / ports so as to enable selective supply of wash liquid towards selected sections of the dishwasher based on (a phase of) a wash cycle performed by the dishwasher.

[0008] The more the number of available predetermined positions, the more the number of possible different configurations of the dishwasher.

[0009] In order to correctly operate the dishwasher, the dishwasher can conveniently be provided with a system for assessing the current position of the diverter. Such a system for assessing the current position of the diverter should accurately identify the correct position of the diverter and at the same time should not be expensive or too bulky. With an increasing number of available predetermined positions, accuracy is a particularly troublesome requirement.

[0010] An aspect of the present invention relates to a dishwasher comprising a wash fluid conduit system comprising a plurality of wash fluid supply conduits, each wash fluid supply conduit for supplying wash fluid to at least one corresponding component of the dishwasher.

[0011] The dishwasher further comprises a sump for collecting wash fluid.

[0012] The sump comprises a plurality of sump outlets, each sump outlet for a corresponding wash fluid supply conduit of the plurality of wash fluid supply conduits.

[0013] The dishwasher further comprises a pump for pumping wash fluid from the sump to the wash fluid conduit system.

[0014] The dishwasher further comprises a flow controller assembly operable for selectively enabling flow of wash fluid from the sump to a selected one or more wash fluid supply conduits.

[0015] The flow controller assembly comprises a discoid flow diverter comprising a plurality of diverter apertures.

[0016] The flow controller assembly comprises a positioning system configured to rotate the flow diverter across a plurality of predetermined diverter positions relative to the sump outlets, each diverter position providing an alignment between one or more diverter apertures and one or more respective sump outlets, thereby enabling flow of wash fluid from each of the one or more sump outlets aligned with the one or more diverter apertures to a corresponding wash fluid supply conduit.

[0017] The positioning system comprises a plurality of cam elements coupled to the flow diverter.

[0018] Each cam element is associated with a corresponding predetermined diverter position.

[0019] Each cam element extends along a corresponding arc of the flow diverter.

[0020] The plurality of cam elements comprises a reference cam element, the arc length of which is different from the arc length of the other cam elements of the plurality of cam elements.

[0021] The positioning system comprises a motor configured to rotate the flow diverter.

[0022] The positioning system comprises a cam follower system comprising a cam follower element configured to mechanically interact with the cam elements and to interact with a detection switch so as to switch the detection switch to a first state when the cam follower element mechanically interacts with a cam element and to a second state when the cam follower element does not mechanically interact with a cam element.

[0023] The positioning system comprises a control unit configured to assess the position of the flow diverter among the predetermined diverter positions and to drive the motor according to the assessed position.

[0024] The control unit is configured to assess the position of the flow diverter by:

[0025] - assessing a position corresponding to a reference predetermined diverter position among the predetermined diverter positions associated with the reference cam element based on the duration of the interaction interval during which the detection switch is in the first state;

[0026] - assessing a position corresponding to a predetermined diverter position among the predetermined diverter positions different from the reference predetermined diverter position by counting the number of times the detection switch switches between the first state and the second state after assessing the reference diverter position.

[0027] In this way, by using a reference diverter position as a reference, it is advantageously possible to efficiently drive the flow diverter across a significant number of different predetermined diverter positions without having to use for each predetermined diverter position a corresponding cam element having a different arc length.

[0028] In practice, thanks to the proposed solution, it is sufficient in principle to provide only two cam elements having two different arc lengths (one for the reference cam element, one for the other cam elements), able to distinguish the reference cam element from the other cam elements. Therefore, even in the presence of a large number of predetermined deflector positions (and therefore of cam elements), the problem of tolerances due to excessively similar (in terms of arc length) cam elements is advantageously avoided.

[0029] According to an embodiment of the application, the control unit is configured to store a counter indicative of the position of the flow deflector among the predetermined deflector positions.

[0030] According to an embodiment of the application, the control unit is configured to set the counter to a first value upon evaluating that the flow deflector has reached an angular position corresponding to the reference predetermined deflector position.

[0031] According to an embodiment of the application, the control unit is configured to update the value of the counter each time the detection switch is switched to the selected state, after evaluating the reference predetermined deflector position.

[0032] According to an embodiment of the application, the arc length of each cam element of the plurality of cam elements, different from the reference cam element, is smaller than the arc length of the reference cam element.

[0033] According to an embodiment of the application, the control unit is configured to evaluate that the flow deflector has reached an angular position corresponding to the reference predetermined deflector position upon evaluating an interaction interval having a duration higher than a first threshold value.

[0034] According to an embodiment of the application, the control unit is configured to evaluate that the flow deflector has reached an angular position corresponding to the reference predetermined deflector position upon evaluating an interaction interval having a duration satisfying both:

[0035] - higher than said first threshold value, and

[0036] - lower than a second threshold value, said second threshold value being higher than said first threshold value.

[0037] According to an embodiment of the application, the control unit is configured to generate a warning indicative of the flow deflector being in an invalid position upon evaluating at least one of:

[0038] - an interaction interval having a duration higher than said second threshold value,

[0039] - an interaction interval having a duration lower than a third threshold value, said third threshold value being lower than said first threshold value.

[0040] According to an embodiment of the present application, the value of the second threshold depends on the arc length of the reference cam element.

[0041] According to an embodiment of the present application, the value of the first threshold depends on the arc length of the cam elements of the plurality of cam elements different from the reference cam element.

[0042] According to an embodiment of the present application, the cam elements of the plurality of cam elements different from the reference cam element all have the same arc length.

[0043] According to an embodiment of the present application, the motor is configured to rotate the flow diverter at a constant rotational speed when driven by the control unit.

[0044] According to an embodiment of the present application, each cam element protrudes parallel to the rotational axis of the flow diverter.

[0045] According to an embodiment of the present application, the control unit is configured to generate a fault warning indicating that the motor and / or the cam follower system is faulty if a timeout expires before a new transition of the detection switch is evaluated after the motor is switched on.

[0046] According to an embodiment of the present application, the control unit is configured to receive an indication of a target predetermined diverter position among the predetermined diverter positions.

[0047] According to an embodiment of the present application, the control unit is configured to drive the motor to rotate the flow diverter until the flow diverter has been evaluated to reach an angular position corresponding to said target predetermined flow diverter position.

[0048] According to an embodiment of the present application, the control unit is configured to switch off the motor when the flow diverter has been evaluated to reach an angular position corresponding to said target predetermined diverter position.

[0049] According to an embodiment of the present application, the control unit is configured to switch on the pump, thereby causing the washing fluid to flow from each of said one or more sump outlets aligned with said one or more diverter orifices to the corresponding washing fluid supply conduit.

[0050] According to an embodiment of the present application, said indication of a target predetermined diverter position among the predetermined diverter positions depends on a phase of a selected washing cycle being performed by the dishwasher.

[0051] According to an embodiment of the present application, the control unit is configured to perform the following operations when the dishwasher is powered on:

[0052] - if the detection switch is evaluated to be in the first state, drive the motor until the detection switch is evaluated to transition to the second state.

[0053] According to embodiments of the application, the positioning system further comprises a driver module configured to:

[0054] - generate a motor drive signal based on the control signal generated by the control unit;

[0055] - provide the motor drive signal to the terminals of the motor.

[0056] According to embodiments of the application, the detection switch comprises a first electrical terminal electrically coupled to the terminals of the motor and a second electrical terminal electrically coupled to an input of the control unit for providing a sensing signal indicative of a state of the detection switch.

[0057] According to embodiments of the application, when the detection switch is in the first state, the first electrical terminal is electrically coupled to the second electrical terminal.

[0058] According to embodiments of the application, when the detection switch is in the second state, the first electrical terminal is electrically decoupled from the second electrical terminal.

[0059] According to embodiments of the application, the driver module and the control unit are powered by a DC supply voltage.

[0060] According to embodiments of the application, the DC supply voltage is lower than 20 volts.

[0061] According to embodiments of the application, the positioning system further comprises a cam support element coaxially coupled to the flow diverter, said cam element being located on said cam support element.

[0062] According to embodiments of the application, said component of the dishwasher comprises at least one of:

[0063] - a dishwasher spray arm;

[0064] - a dishwasher detergent dispenser;

[0065] - a filter of a sump;

[0066] - a dishwasher tank;

[0067] - a dishwasher heat exchanger.

[0068] Another aspect of the application relates to a method for operating a dishwasher.

[0069] The method comprises selectively enabling a flow of wash fluid from a dishwasher sump to a selected one or more wash fluid supply conduits of a dishwasher wash fluid conduit system.

[0070] The selectively enabling includes rotating the flat-round flow diverter across a plurality of predetermined diverter positions relative to sump outlets of the sumps, each sump outlet corresponding to a corresponding scrubbing fluid supply conduit.

[0071] Each diverter position provides alignment between one or more diverter apertures on the flow diverter and one or more corresponding sump outlets, thereby enabling flow of scrubbing fluid from each of the one or more sump outlets aligned with the one or more diverter apertures to the corresponding scrubbing fluid supply conduit.

[0072] A plurality of cam elements are coupled to the flow diverter, each cam element associated with a corresponding predetermined diverter position, each cam element extending along a corresponding arc of the flow diverter, the plurality of cam elements including a reference cam element having an arc length different from arc lengths of other cam elements of the plurality of cam elements.

[0073] The selectively enabling includes evaluating a position of the flow diverter among the predetermined diverter positions by a cam follower system, the cam follower system including a cam follower element configured to mechanically interact with the cam elements and to interact with a detection switch to transition the detection switch to a first state when the cam follower element mechanically interacts with a cam element and to a second state when the cam follower element does not mechanically interact with a cam element.

[0074] The evaluating the position of the flow diverter includes measuring durations of one or more interaction intervals of the detection switch in the first state.

[0075] The evaluating the position of the flow diverter includes evaluating a position corresponding to a reference predetermined diverter position of the predetermined diverter positions associated with the reference cam element based on the measured durations of the one or more interaction intervals.

[0076] The evaluating the position of the flow diverter includes, after evaluating the reference diverter position, counting a number of times the detection switch transitions between the first state and the second state to a selected state.

[0077] The evaluating the position of the flow diverter includes evaluating a position corresponding to a predetermined diverter position of the predetermined diverter positions different from the reference diverter position based on the counted number of times.

[0078] According to an embodiment of the application, the method comprises setting a counter indicating the position of the flow diverter among the predetermined diverter positions to a first value upon assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position.

[0079] According to an embodiment of the application, the method comprises updating the value of the counter each time the detection switch switches to the selected state upon assessing the reference predetermined diverter position.

[0080] According to an embodiment of the application, the arc length of each cam element of the plurality of cam elements different from the reference cam element is smaller than the arc length of the reference cam element.

[0081] According to an embodiment of the application, the method further comprises assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon assessing an interaction interval having a duration higher than a first threshold value.

[0082] According to an embodiment of the application, the method further comprises assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position upon assessing an interaction interval having a duration satisfying both:

[0083] - higher than said first threshold value, and

[0084] - lower than a second threshold value, said second threshold value being higher than said first threshold value.

[0085] According to an embodiment of the application, the method further comprises generating a warning indicating that the flow diverter is in an invalid position upon assessing at least one of:

[0086] - an interaction interval having a duration higher than said second threshold value,

[0087] - an interaction interval having a duration lower than a third threshold value, said third threshold value being lower than said first threshold value. BRIEF DESCRIPTION OF DRAWINGS

[0088] These and other characteristics and advantages of the present application will become apparent from the following detailed description, to be read in conjunction with the appended drawings, wherein:

[0089] FIG. 1 is a perspective view of a dishwasher according to an embodiment of the application;

[0090] FIG. 2 is a perspective view of a sump and pump of a dishwasher according to an embodiment of the application; FIG. 1

[0091] FIG. 3 is​FIG. 1 Enlarged view of a sump according to the prior art and a flow controller assembly according to an embodiment of the application;

[0092] FIG. 4A Perspective view from above of a cam support element of a flow controller assembly according to an embodiment of the application;

[0093] FIG. 4B Perspective view from below of a cam support element of a flow controller assembly according to an embodiment of the application; FIG. 4A

[0094] FIG. 5 Detailed perspective view of a cam support element, and of parts of a cam follower system, of a flow controller assembly according to an embodiment of the application;

[0095] FIG. 6 Illustrates the evolution over time of the state of a detection switch according to an exemplary embodiment of the application;

[0096] FIG. 7A-7B Illustrates a flowchart of the main operations performed by a control unit 125 of a positioning system according to an embodiment of the application, and

[0097] FIG. 8 Illustrates a non-limiting example of circuit elements of a positioning system (part of) a flow controller assembly according to an exemplary embodiment of the application. DETAILED DESCRIPTION

[0098] FIG. 1 Illustrates a dishwasher 100 according to an embodiment of the application. The dishwasher 100 has a top portion 102, a bottom portion 104, and a tub 106 extending between the top portion 102 and the bottom portion 104. In FIG. 1 , the tub, the top portion and the bottom portion are represented in dashed lines. The top portion 102 and the bottom portion 104 define a chamber 103. A bottom panel 108 (partially sectioned in FIG. 1 to illustrate internal details) is located in the chamber 103, close to the bottom portion 104. The tub 106 comprises a plurality of walls 110. Dishes, cookware and other utensils (also referred to herein as "contents" of the dishwasher 100) can be placed in the chamber 103 to be processed, e.g. washed. The dishwasher 100 can also comprise a slidable lower rack and a slidable upper rack (not shown) for holding the contents of the dishwasher. These racks can be moved in and out of the chamber 103. FIG. 1 A door 112 is also shown in dashed lines in

[0099] ​According to embodiments of the present application, the dishwasher 100 comprises a sump 114 in which wash fluid is typically collected under the influence of gravity. The dishwasher 100 uses wash fluid to treat (e.g. wash, rinse and sanitize) the contents of the dishwasher 100, and the wash fluid can comprise, for example, water, fresh water, softened water, water mixed with detergent, rinse aid and any other suitable wash fluid and / or rinse fluid in any combination.

[0100] According to embodiments of the present application, the wash fluid collected in the sump 114 can be pumped by a circulation pump 116 through a wash fluid conduit system 118 comprising a plurality of wash fluid supply conduits, each fluidly connected to a corresponding component of the dishwasher 100 (e.g. one or more spray arms) for supplying wash fluid thereto.

[0101] In FIG. 1 In the exemplary embodiment shown, the wash fluid conduit system 118 comprises, among others:

[0102] - a wash fluid supply conduit connected to the top spray arrangement 120;

[0103] - a wash fluid supply conduit connected to the middle spray arm 122;

[0104] - a wash fluid supply conduit connected to the lower spray arm 124.

[0105] The inventive concept can be applied directly to cases where a different number of spray arms is provided.

[0106] According to FIG. 1 According to the embodiments of the present application shown, the top spray arrangement 120 is proximate to the top portion 102 of the dishwasher, the lower spray arm 124 is proximate to the bottom panel 108, and the middle spray arm 122 is located between the top spray arm and the lower spray arm.

[0107] The inventive concept can be applied directly to cases where the spray arms are located in different positions.

[0108] The spray arrangements / arms 120, 122 and 124 are located in the chamber 103 and are configured for spraying wash fluid under pressure onto the contents in the chamber 103 during use of the dishwasher.

[0109] According to embodiments of the present application, the dishwasher 100 further comprises a control unit 125 (schematically illustrated in the figures with a dashed square) configured to control operation of the dishwasher 100 by driving components of the dishwasher based on (a stage of) a wash cycle performed by the dishwasher 100. For example, the control unit 125 is configured to selectively operate the pump 116 to send wash fluid to at least one of the spray arms / devices 120, 122 and / or 124. In some embodiments, the control unit 125 can comprise a memory for storing data, such as operating routines of the dishwasher 100.

[0110] In FIG. 1 Embodiments of the present application are illustrated, the control unit 125 is located at the top portion 102 of the dishwasher 100. The control unit 125 can be located in different portions of the dishwasher 100, for example at the bottom portion 104 of the dishwasher 100.

[0111] According to embodiments of the present application, the sump 114 is fluidly coupled to a flow controller assembly, which will be described in greater detail below, configured to selectively enable flow of wash fluid from the sump 114 to a selected one or more wash fluid supply conduits.

[0112] FIG. 2 is a perspective view of the sump 114 and the pump 116 according to embodiments of the present application. FIG. 3 is a zoomed-in view of the sump 114 and a flow controller assembly, generally identified in the figures with reference numeral 150, according to embodiments of the present application.

[0113] According to embodiments of the present application, the sump 114 comprises a sump housing 132 defining a sump region 151 configured to contain wash fluid. A collector opening 131 is provided on a top side of the sump housing 132 to allow wash fluid from the tub 106 to be collected into the sump region 151 under the influence of gravity.

[0114] According to embodiments of the present application, a removable filter unit (not illustrated in FIG. 2 and FIG. 3 ) is provided at the collector opening 131 for filtering wash fluid collected into the sump 114.

[0115] According to embodiments of the present application, the pump 116 has an input port connected to an output port 133 (see FIG. 3 ) of the sump 114 for receiving wash fluid contained in the sump region 151 of the sump 114.

[0116] According to embodiments of the present application, the flow controller assembly 150 is housed in a corresponding flow controller housing 136 having an inlet 169 fluidly connected to the output port of the pump 116. According to embodiments of the present application, the flow controller housing 136 is connected to the sump 114, e.g. by means of the engagement means 137, and defines a volume adapted to receive the washing fluid pumped by the pump 116 through the inlet 169.

[0117] According to embodiments of the present application, a housing opening 155 is provided on the top side of the flow controller housing 136, which, as will be described hereinafter, 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 embodiments of the present application, each of said sump outlets 138, 140, 142 is in fluid communication with a corresponding fluid supply conduit of the washing fluid conduit system 118, which in turn is fluidly connected to a corresponding component of the dishwasher 100. According to the embodiments of the present application 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 different portions of the sump 114.

[0118] In the exemplary embodiment illustrated in the figures, the first sump outlet 138 is in fluid communication with a fluid supply conduit connected to the middle spray arm 122, the second sump outlet 140 is in fluid communication with a fluid supply conduit connected to the top spray device 120, and the third sump outlet 142 is in fluid communication with a fluid supply conduit connected to the lower spray arm 124.

[0119] Thus, in this exemplary embodiment, the first sump outlet 138 is configured to provide washing fluid from the sump 114 to the middle spray arm 122, the second sump outlet 140 is configured to provide washing fluid from the sump 114 to the top spray device 120, and the third sump outlet 142 is configured to provide washing fluid from the sump 114 to the lower spray arm 124. In other embodiments, the sump outlets 138, 140, 142 can enable the supply of washing fluid from the sump 114 to any of the spray arms / devices 120, 122, 124 and / or any other component of the washing fluid conduit system 118 of the dishwasher 100.

[0120] According to embodiments of the present application, these sump outlets are spaced apart in a manner required for their combined action with the flow controller 150 described hereinafter to selectively supply washing fluid to the corresponding washing fluid conduit.

[0121] In exemplary embodiments of the present application, a first additional sump outlet 144 and a second additional sump outlet 146 are further provided, which can enable the supply of wash fluid from the sump 114 to various components of the dishwasher 100.

[0122] For example, the first additional sump outlet 144 and / or the second additional sump outlet can provide wash fluid from the sump 114 to components of the dishwasher 100 outside the utensil washing chamber 103 of the tub 106 and / or can provide wash fluid from the sump 114 to, for example, any of: a detergent dispenser for diluting detergent prior to dispensing the detergent into the chamber 103 (e.g., comprised within the door 112 of the dishwasher 100, as shown), a filter unit of the sump 114, an additional tank spaced apart from the sump 114 and arranged outside the sump (e.g., for containing clean water / wash fluid and / or cleaned and filtered wash fluid / water for use at a later time during a utensil washing cycle), a heat exchanger for exchanging warm water / wash fluid with clean water / wash fluid to rinse utensils within the dishwasher or a heat exchanger for exchanging refrigerant fluid of a heat pump system with water, a specific rotating / fixed wash fluid spraying device configured to spray wash fluid in a specific direction according to user preference, and any other suitable component of the dishwasher. FIG. 1

[0123] It is noted that the inventive concept of the present application can be applied to cases where different numbers of sump outlets and / or additional sump outlets can be provided, for example, cases where no additional sump outlets are provided.

[0124] According to embodiments of the present application, the flow controller assembly 150 comprises a flow diverter 152 element having the shape of a plate comprising a plurality of diverter orifices 153 (see FIG. 3 ) In exemplary embodiments of the present application shown in the drawings, the flow diverter 152 has four diverter orifices 153, however different numbers of diverter orifices 153 can be envisaged. In exemplary embodiments of the present application shown in the drawings, the flow diverter 152 has the shape of a disc. However, similar considerations apply in cases where the flow diverter 152 has a different shape of a flat circle, for example, in cases where the flow diverter is a polygonal plate. According to embodiments of the present application, the flow diverter 152 is configured to be received in a corresponding receiving portion 148 of the sump 114, which is in fluid communication with the sump outlets 138, 140, 142 and the additional sump outlets 144, 146, if present.

[0125] ​According to embodiments of the application, the flow controller housing 136 fits around or encloses 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.

[0126] According to embodiments of the application, 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.

[0127] According to embodiments of the application, the positioning system of the flow controller assembly 150 comprises a motor 156 configured to rotate the flow diverter 152 about its rotational axis (identified with reference R in FIG. 3 According to embodiments of the application, the motor 156 is configured to rotate the flow diverter 125 at a constant rotational speed when driven by a control unit 152.

[0128] According to embodiments of the application, the positioning system of the flow controller assembly 150 is configured to rotate the flow diverter 152 across a plurality of predetermined operational diverter positions T; (i = 1, 2,...), wherein each predetermined diverter position Pi provides an alignment between one or more diverter apertures 153 and one or more corresponding sump outlets of these available sump outlets 138, 140, 142, 144, 146, thereby enabling the washing fluid received in the volume of the flow controller housing 136 by the pump 116 to flow from each of said one or more sump outlets aligned with said one or more diverter apertures to a corresponding washing fluid supply conduit.

[0129] According to embodiments of the application, the positioning system of the flow controller assembly 150 is further configured to rotate the flow diverter 152 to a closed diverter position CP which does not provide any alignment between the diverter apertures 153 and the sump outlets, thereby preventing the washing fluid from flowing through any sump outlet.

[0130] According to embodiments of the application, each predetermined diverter position Ti and the closed diverter position CP corresponds to a respective angular position of the flow diverter 152.

[0131] According to embodiments of the application, the positioning system of the flow controller assembly 150 comprises a control unit configured to drive the motor 156 to rotate the flow diverter 152 to a target position among these predetermined diverter positions Ti based on (a phase of) a washing cycle performed by the dishwasher 100.

[0132] In the exemplary embodiments of the application considered here, 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 the case where the control unit of the positioning system is a dedicated control unit different from the control unit 125.

[0133] According to embodiments of the application, and as will be described in detail hereinafter, the positioning system of the flow controller assembly 150 is configured to assess the current position of the flow diverter 152 among the predetermined diverter positions Ti (and optionally also the closed diverter position CP).

[0134] According to embodiments of the application, 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 FIG. 3 ) and comprising a plurality of protruding cam elements.

[0135] FIG. 4A and FIG. 4B shows a detailed view of the cam support element 154 according to embodiments of the application. More specifically, FIG. 4A is a perspective view of the cam support element 154 seen from above, and FIG. 4B is a perspective view of the cam support element 154 seen from below.

[0136] According to embodiments of the application, the cam support element 154 comprises a substantially flat body, such as a disc-shaped body, having a top surface 160 facing the flow diverter 152 and a bottom surface 162 opposite the top surface 160.

[0137] According to embodiments of the application, 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 center of the top surface 160 and configured to engage into a corresponding hole provided on the flow diverter 152 at its rotation axis R.

[0138] According to embodiments of the application, the cam support element 154 is configured to be coupled to the drive shaft of the motor 156 (see FIG. 3 ) through a receiving hole 166 located in the center of the bottom surface 162, which is configured to receive the drive shaft of the motor 156.

[0139] 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 switched on.

[0140] According to an embodiment of the present application, the cam support element 154 comprises a plurality of cam elements C(i) located at a peripheral portion of the bottom surface 162 and protruding from the bottom surface towards the motor 156 (see Fig. 2). The concept of the present application can be directly applied to the case in which the cam elements C(i) are located in different portions of the cam support element 154, for example along a portion of a circle of the bottom surface 162 corresponding to a circle having its centre at the receiving hole 166 and a radius smaller than the radius of the disc-shaped body, or to the case in which the cam elements C(i) protrude towards different directions, for example perpendicular to the rotation axis R. FIG. 4B

[0141] According to an embodiment of the present application, each cam element C(i) of the plurality of cam elements C(i) is associated with a corresponding predetermined diverter position T1. In the exemplary embodiment of the present application illustrated in the drawings, the plurality of cam elements C(i) comprises eight cam elements C(1), C(2),..., C(8), each of which is associated with a corresponding predetermined diverter position among the eight predetermined diverter positions T1, T2,..., T8. Different numbers of cam elements C(i) can be envisaged.

[0142] According to an embodiment of the present application, 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.

[0143] As can be seen in Fig. 2, according to an embodiment of the present application, each cam element C(i) is shaped so as to comprise an inclined portion and a flat portion. However, similar considerations apply to the case in which the cam elements C(i) have different shapes. FIG. 4B

[0144] According to an embodiment of the present application, the plurality of cam elements C(i) comprises a reference cam element having an arc length different from the arc length of the other cam elements C(i) of the plurality. In the example illustrated in the drawings, the reference cam element is the cam element C(1) corresponding to the predetermined diverter position T1.

[0145] According to an embodiment of the present application, the arc length of the reference cam element is longer than the arc length of the other cam elements. According to another embodiment of the present application, the arc length of the reference cam element is shorter than the arc length of the other cam elements. In the example illustrated in the drawings, the arc length of the reference cam element C(1) is longer than the arc length of the other cam elements C(i) (i = 2 to 8).

[0146] ​​According to an embodiment of the present application, the cam elements C(i) different from the reference cam element all have the same length, which is different (i.e. longer or shorter) than the length of the reference cam element. According to another embodiment of the present application, the length of some (e.g. each) of the cam elements C(i) different from the reference cam element can be longer or shorter than the length of the other cam elements C(i) different from the reference cam element (in any case, the length of the reference cam element is longer or shorter than all the cam elements different from the reference cam element). In the example shown in the attached figures, the arc length of the reference cam element C(1) 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(1) have the same length.

[0147] According to an embodiment of the present application, the positioning system of the flow controller assembly 150 further comprises a cam follower system 180, which is located below the cam support element 154 (see Fig. 2) and is configured to mechanically interact with the cam elements C(i) of the cam support element 154. FIG. 3 ) and is configured to mechanically interact with the cam elements C(i) of the cam support element 154.

[0148] FIG. 5 is a more detailed perspective view of the cam support element 154, according to an embodiment of the present application, and of several parts of the cam follower system 180.

[0149] According to an embodiment of the present application, the cam follower system 180 comprises a cam follower element 182, which is configured to mechanically interact with the cam elements C(i) of the cam support element 154.

[0150] According to an embodiment of the present application, the cam follower system 180 comprises a detection switch 184, which is configured to mechanically interact with the cam follower element 182. According to an embodiment of the present application, the detection switch 184 is configured to switch to a first state SI when the cam follower element 182 is mechanically interacting with the cam elements C(i), and to switch to a second state S2 when the cam follower element 182 is not mechanically interacting with the cam elements C(i).

[0151] According to an example embodiment of the application, the cam follower system 180 comprises a biasing system, e.g. comprising one or more springs, configured to bias the cam follower element 182 towards 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, thereby causing the detection switch 184 to switch 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 by the biasing system towards the bottom surface 162 of the cam support element 154, thereby causing the detection switch 184 to switch to the second state S2.

[0152] In this way, the detection switch 184 switches between the first state SI and the second state S2 during the rotation of the flow diverter 152 (and thus of the cam support element 154). In particular, each time a cam element C(i) passes at (e.g. above) the position of the detection switch 184, the detection switch 184 switches from the second state S2 to the first state SI. Then, as long as the cam element C(i) is at (e.g. above) the position of the detection switch 184, the detection switch 184 remains in the first state SI. As soon as the cam element C(i) leaves the position at (e.g. above) the position of the detection switch 184, the detection switch 184 switches back from the first state SI to the second state S2. The detection switch 184 remains in the second state S2 until the rotation of the flow diverter 152 (and thus of the cam support element 154) causes a new cam element C(i) to pass at (e.g. above) the position of the detection switch 184. When the latter condition is verified, the detection switch 184 switches from the second state S2 to the first state SI.

[0153] It is noted that, although reference has been made in the illustrated embodiments of the application to a cam support element 154 wherein each cam element C(i) protrudes from the bottom surface 162 of the cam support element 154 in a direction substantially parallel to the rotation axis R, and the cam follower element 182 is configured to move in said direction substantially parallel to the rotation axis R, similar considerations apply also to the case where the cam elements C(i) protrude from the cam support element 154 in a different direction, such as substantially perpendicular to the rotation axis R, and the cam follower element 182 is configured to move in said different direction substantially perpendicular to the rotation axis R.

[0154] According to another embodiment of the application, 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.

[0155] According to an embodiment of the application, the cam follower system 180 further comprises a control unit of the positioning system of the flow controller assembly 150, which control unit is configured to evaluate the current position of the flow diverter 152 among the predetermined diverter positions Ti and to drive the motor 156 depending on the evaluated position. According to another embodiment of the application, the cam follower system 180 comprises a dedicated control unit, which is different from the control unit of the positioning system of the flow controller assembly 150.

[0156] Due to the fact that, according to an embodiment of the application, the arc length of the reference cam element C(1) is different from the arc length of the other cam elements C(i), it is advantageously possible to evaluate when the current rotational position of the flow diverter 152 corresponds to the reference diverter position T1 (among the predetermined diverter positions Ti) corresponding to the reference cam element C(1) by observing the evolution of the state of the detection switch 184 over time.

[0157] In particular, according to an embodiment of the application, the control unit 125 is configured to evaluate the position of the flow diverter 152 corresponding to the reference diverter position T1 based on the duration of the interaction interval II during which the detection switch 184 remains in the first state S1.

[0158] According to an embodiment of the application in which the arc length of the reference cam element C(1) is longer than the arc length of the other cam elements C(i) (as illustrated in the figures), the control unit 125 is configured to evaluate the position of the flow diverter 152 corresponding to the reference diverter position T1 when an interaction interval II is detected which has a duration longer than the duration of the other interaction intervals II.

[0159] According to an (not illustrated) embodiment of the application in which the arc length of the reference cam element C(1) is shorter than the arc length of the other cam elements C(i), the control unit 125 is configured to evaluate the position of the flow diverter 152 corresponding to the reference diverter position T1 when an interaction interval II is detected which has a duration shorter than the duration of the other interaction intervals II.

[0160] FIG. 6 It is illustrated when eight cam elements C(i) (i = 1 to 8) are provided and the reference cam element C(1) has a first arc length while the other cam elements C(i) (i = 2 to 8) have all the same second arc length smaller than the first arc length (as in the figures). FIG. 4A and FIG. 4B6. Evolution of the state of the detection switch 184 over time according to an exemplary embodiment of the present invention during rotation of the flow diverter 152 at a constant rotational speed, in the exemplary embodiment of the present invention shown in FIG.

[0161] In the example considered, each full revolution of the flow diverter 152 around the axis of rotation R (in FIG. 6 605 ) provides a sequence of eight interaction intervals II(i) (i=1 to 8) during which the detection switch 184 is maintained in the first state S1 , each interaction interval corresponding to a respective cam element in the cam elements C(i).

[0162] like FIG. 6 As shown, there is an interaction interval II(1) that lasts longer than every other interaction interval II(i). This interaction interval II(1) corresponds to the reference diverter position T1 because the longer arc length of the corresponding reference cam C(1) results in a longer time for the detection switch 184 to be in the state S1 (because the rotational speed of the flow diverter 152 is constant).

[0163] According to an embodiment of the present invention, the control unit 125 is configured to evaluate the position of the flow diverter 152 corresponding to a predetermined diverter position among these predetermined diverter positions Ti that is different from the reference diverter position T1 by counting the number of times the detection switch 184 is switched to a selected state between the first state S1 and the second state S2 after evaluating the reference diverter position T1.

[0164] According to an embodiment of the invention, the control unit 125 is configured to store a position counter PI indicating the actual (angular) position of the flow diverter 152 in one of these predetermined diverter positions Ti, for example in an electronic memory included in the control unit 125 or connected to the control unit.

[0165] According to an embodiment of the present invention, the control unit 125 is configured to set the position counter PI to a first value (PI=1 in the considered exemplary embodiment of the present invention) after evaluating that the flow diverter 152 has reached an angular position corresponding to the reference diverter position T1. In the considered exemplary embodiment of the present invention, when the position counter PI is equal to 1, it means that the flow diverter 152 is in the angular position corresponding to the reference diverter position T1.

[0166] According to an embodiment of the application, the control unit 125 is configured to update the value of the position counter PI (in the exemplary embodiment under consideration of the application, by increasing PI by one) each time the detection switch 184 is switched to the first state SI after evaluating the reference diverter position Tl. According to another embodiment of the application, the control unit 125 is configured to update the value of the position counter PI each time the detection switch 184 is switched to the second state S2 after evaluating the reference diverter position Tl. In the exemplary embodiment under consideration of the application, when the position counter PI is equal to i (i > 1 ), it means that the flow diverter 152 is in an angular position corresponding to the predetermined diverter position Ti.

[0167] According to an embodiment of the application, the control unit 125 is configured to set the value of the position counter PI to a null value (in the exemplary embodiment under consideration of the application, PI = 0) indicating an unknown position of the flow diverter 152 when the control unit 125 is not able (e.g. has not yet been able) to evaluate the current position of the flow diverter 152.

[0168] By referring to the time diagram of the non-limiting example shown in FIG. 6 Assume that, before the flow diverter 152 is driven to rotate, the initial angular position of the flow diverter 152 is between the predetermined diverter positions T6 and T7, but the control unit 125 does not know 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 in the second state S2.

[0169] 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 in the first state SI for a relatively short interaction interval II(7) and then returns 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 enough information to evaluate the current angular position of the flow diverter 152. Therefore, the position counter PI remains at the null value 0.

[0170] Afterwards, when the cam follower element 182 is pushed by the cam element C(8), the detection switch 184 switches to the first state SI. Since the cam element C(8) is not the reference cam element C(l), the detection switch 184 remains in the first state SI for a relatively short interaction interval II(8) and then returns 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 enough information to evaluate the current angular position of the flow diverter 152. Therefore, the position counter PI remains at the null value 0.

[0171] After the cam follower element 182 is pushed by the cam element C(1), the detection switch 184 switches to the first state S1. Since the cam element C(1) is the reference cam element, the detection switch 184 remains in the first state S1 for a relatively long interaction interval II(1) and the control unit 125 evaluates 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 II(1), the detection switch 184 returns to the second state S2.

[0172] After the cam follower element 182 is pushed by the cam element C(2), the detection switch 184 switches to the first state S1. Since the cam element C(2) is not the reference cam element C(1), the detection switch 184 remains in the first state S1 for a relatively short interaction interval II(8) and then returns to the second state S2. Moreover, since the position counter PI is at a value different from the null value 0 (i.e. 1), the control unit 125 increases the position counter PI by 1, i.e. PI = 1 + 1 = 2. In this way, since the position counter PI is equal to i = 2, the control unit 125 determines that the current angular position of the flow diverter 152 corresponds to the predetermined reference position Ti = T2.

[0173] The process is iterated by increasing the position counter PI by 1 each time the detection switch 184 switches to the first state S1 and determining that the current angular position of the flow diverter 152 corresponds to the predetermined reference position equal to Ti (where i is the value of the increasing position counter PI).

[0174] When the cam follower element 182 mechanically interacts again with the cam element C(1) after the flow diverter 152 has completed a full turn, the detection switch 184 remains in the first state S1 for a relatively long interaction interval II(1). In this case, the control unit 125 evaluates 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.

[0175] In other words, according to an embodiment of the present application, and starting from the condition that the current position of the flow diverter 152 is unknown (PI = 0), the control unit 125 is configured to perform a first phase which involves evaluating when the angular position of the flow diverter 152 reaches the reference diverter position T1. Then, once the flow diverter 152 has been evaluated to be at the reference diverter position T1, this information is used by the control unit 152 as a reference to evaluate when the angular position of the flow diverter 152 reaches the subsequent predetermined diverter positions T2, T3, T4,... in a subsequent second phase.

[0176] In this way, by exploiting the reference diverter position T1 as a reference, it is advantageously possible to efficiently drive the flow diverter 152 across a significant number of different predetermined diverter positions Ti without having to use, for each predetermined diverter position Ti, a corresponding cam element with a different arc length. In fact, according to embodiments of the present application, it is in principle sufficient to provide only two cam elements C(i) with different arc lengths (one for the reference cam element, one for the other cam elements) while being able to distinguish the reference cam element from the other cam elements. Thus, even in the presence of a large number of predetermined diverter positions (and thus of cam elements), tolerance problems due to excessively similar (in terms of arc length) cam elements are advantageously avoided.

[0177] It is noted that, although in the exemplary embodiments of the present application described above the position counter PI is increased from a reference value (such as 1) each time the detection switch 184 is detected to transition from the second state S2 to the first state S1, similar considerations apply if the position counter PI is decreased from a reference value (such as 8) each time the detection switch 184 is detected to transition from the second state S2 to the first state S1. FIG. 6

[0178] According to embodiments of the present application, the control unit 125 is configured to receive an indication TP of a target (angular) position among the predetermined diverter positions Ti that the flow diverter 152 has to reach based on (a phase of) a washing cycle performed by the dishwasher 100. According to embodiments of the present application, the control unit 125 is configured to stop the motor 156 as soon as the position counter PI matches (e.g., is equal to) the target position indication TP, thereby keeping the flow diverter 152 in the desired target position so as to enable the washing fluid received in the volume of the flow controller housing 136 to flow to the washing fluid supply conduit selected by the flow diverter 152 (see FIG. 1 and FIG. 3 ) of the washing fluid conduit system 118.

[0179] FIG. 7A-7B A flowchart illustrating the main operations performed by the control unit 125 of the positioning system of the flow controller assembly 150 for evaluating the position of the flow diverter 152 according to embodiments of the present application is shown.

[0180] According to embodiments of the present application, upon power-up of the dishwasher 100, the position counter PI and the target position indication TP are set to a null value (e.g., 0) (block 702).

[0181] ​According to embodiments of the application, 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), it means that the angular position of the flow diverter 152 is such that one of the cam elements C(i) pushes the cam follower element 182, and the control unit 125 switches on the motor 156 to rotate the flow diverter 152 until the detection switch 184 switches to the second state S2, i.e. until the cam follower element 182 disengages from the cam C(i) (block 706). According to embodiments of the application, the control unit 125 can be further configured to generate a warning indicating that there is a fault in the positioning system of the flow controller assembly 150 (e.g. a fault in the motor 156 and / or in the cam follower system 180) if the detection switch 184 does not switch to the second state S2 within a corresponding timeout period.

[0182] According to embodiments of the application, as soon as the detection switch 184 switches to the second state S2 or if the detection switch 184 is already in the second state S2 when the dishwasher is powered on (exit branch N of block 704), the control unit 125 enters a waiting loop to wait for receiving a (new) target position indication TP (block 708 and its exit branch N, back to the same block 708).

[0183] According to embodiments of the application, when the control unit 125 receives a target position indication TP (exit branch Y of block 708), e.g. because a new phase of a washing cycle to be performed by the dishwasher 100 requires a corresponding new positioning of the flow diverter 152, the control unit 125 switches on the motor 156 to enable the rotation of the flow diverter 152 and starts a timer TM (block 710).

[0184] According to embodiments of the application, 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 indicating that there is a fault in the positioning system of the flow controller assembly 150 (e.g. a fault in the motor 156 and / or in the cam follower system 180) (block 714, back to block 708).

[0185] According to embodiments of the application, if the control unit 125 evaluates that the detection switch 184 switches 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 operating correctly, since the flow diverter 152 is actually rotating and this rotation is detected by the switching of the detection switch 184 caused by the mechanical interaction of the cam elements C(i) of the rotating flow diverter 152 with the cam follower element 182.

[0186] Then, according to embodiments of the application, the control unit 125 measures the duration D(i) of the interaction interval II(i) during which the detection switch 184 is maintained in the first state SI by the cam element C(i) (block 720). According to embodiments of the application, the duration D(i) is computed by the control unit 125 based on a timer that is started when the detection switch 184 transitions to the first state SI (e.g. at the exit branch Y of block 712) and stopped when the detection switch 184 transitions to the second state S2.

[0187] According to embodiments of the application, the control unit 125 compares the measured duration D(i) of the interaction interval II(i) with a short cam limit threshold SCL and a long cam limit threshold LCL indicative of maximum duration limits (block 730). According to embodiments of the application, the short cam limit threshold SCL is set to a value corresponding to (e.g. just above) the maximum expected duration of the interaction interval II(i) associated with one of the ("short") cam elements C(i) different from the reference cam element C(i). According to embodiments of the application, the long cam limit threshold LCL is set to a value corresponding to (e.g. just above) the maximum expected duration of the interaction interval II(1) associated with the ("long") reference cam element C(1). According to embodiments of the application, the long cam limit threshold LCL is higher than the short cam limit threshold SCL.

[0188] According to embodiments of the application, 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 shorter than the long cam limit threshold LCL (exit branch Y of block 730), it means that the cam element C(i) that caused the transition of the detection switch 184 is the reference cam element C(1). In this case, according to embodiments of the application, the control unit 125 sets the position counter PI to 1 to indicate that the flow diverter 152 has been evaluated as being in the reference diverter position T1.

[0189] According to embodiments of the application, 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 longer than the minimum threshold MINL set to a value large enough to filter out unwanted errors and noise affecting the measurement operation (exit branch Y of block 740), it means that the cam element C(i) that caused the detection switch 184 to switch is one of the cam elements C(i) different from the reference cam element C(1). In this case, according to embodiments of the application, 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 enough information to assess the current angular position of the flow diverter 152 (as the reference diverter position T1 has not been identified yet) and therefore the control unit 125 keeps the motor 156 active to allow the flow diverter 152 to further rotate. In this case, the operation flow returns to block 710 to wait for the next switch of the detection switch 184 to the first state SI caused by the next cam element C(i). Alternatively, if 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 at a predetermined diverter position Ti, where i is equal to the current value of the position counter PI. According to embodiments of the application, the minimum threshold MINL is lower than the short cam limit threshold SCL.

[0190] According to embodiments of the application, 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 as this interaction interval II(i) cannot be identified as being associated with any cam element C(i) (block 750).

[0191] According to embodiments of the application, 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).

[0192] According to embodiments of the application, 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 that the rotation of the flow diverter 152 stops at the requested position indicated by the target position indicator TP (return to block 708).

[0193] According to embodiments of the application, if the current value of the position counter PI does not (still) equal the target position indication TP (exit branch N of block 760), the control unit 125 keeps the motor 156 activated to allow the flow diverter 152 to further rotate. In this case, the operation flow returns to block 710 to wait for the next transition of the detection switch 184 to the first state SI caused by the next cam element C(i).

[0194] FIG. 8 A non-limiting example of circuit elements of (part of) the positioning system of the flow controller assembly 150 according to exemplary embodiments of the application is shown.

[0195] According to embodiments of the application, the positioning system of the flow controller assembly 150 further comprises a driver module 810 configured to drive the motor 156 by means of a motor drive signal MDS generated based on the control signal CS provided by the control unit 125.

[0196] According to embodiments of the application, the control signal CS generated by the control unit 125 comprises two pulse width modulated (PWM) control signals CS with a phase offset (such as 180°) present. According to embodiments of the application, the control signal CS has a duty cycle of less than or equal to 50%, for example equal to 45%.

[0197] According to embodiments of the application, the driver module 810 comprises an H-bridge circuit configured to receive the control signal CS and to generate a (differential) motor drive signal MDS to be provided across the two electrical terminals of the motor 156 accordingly.

[0198] According to embodiments of the application, the detection switch 184 comprises a first electrical terminal electrically coupled to one of the two electrical terminals of the motor 156 and a second electrical 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 embodiments of the application, when the detection switch 184 is in the first state SI, the first electrical terminal of the detection switch 184 is electrically coupled to the second electrical terminal of the detection switch 184. According to embodiments of the application, when the detection switch 184 is in the second state S2, the first electrical terminal of the detection switch 184 is electrically decoupled from the second electrical terminal of the detection switch 184.

[0199] According to embodiments of the application, the control unit 125 is powered by a DC supply voltage VS1 (e.g., < +20 V, such as +5 V) and the driver module 810 is powered by a DC supply voltage VS2 (e.g., < +20 V, such as +12 V). According to embodiments of the application, the motor 156 is an AC motor, for example a 12 V AC motor.

[0200] According to an embodiment of the application, the DC supply voltages VS1 and VS2 are generated by a voltage supply unit 820 connected to the mains.

[0201] According to an embodiment of the application, the second electrical terminal of the detection switch 184 is electrically coupled to an input terminal of the control unit 125 through a conditioning network comprising a voltage divider 830 and a pull-up element 840.

[0202] According to an embodiment of the application, when the detection switch 184 is in the first state S1 due to the cam follower element 182 mechanically interacting with the cam element C(i), the first electrical terminal of the detection switch 184 is electrically coupled to the second electrical 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.

[0203] According to an embodiment of the application, when the detection switch 184 is in the second state S1 due to the cam follower element 182 not mechanically interacting with any cam element C(i), the first electrical terminal of the detection switch 184 is electrically decoupled from the second electrical 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.

[0204] Due to the fact that in the architecture shown the voltages managed by the control unit 125, the driver module 810 and the motor 156 are “low” voltages, i.e. ≤ +20V, it is possible to advantageously use Class I plastics to implement the elements of the flow controller assembly 150, and / or it is possible to advantageously use low voltage AC motors to implement the motor 156. FIG. 8 In the architecture shown, the voltages managed by the control unit 125, the driver module 810 and the motor 156 are “low” voltages, i.e. ≤ +20V, it is possible to advantageously use Class I plastics to implement the elements of the flow controller assembly 150, and / or it is possible to advantageously use low voltage AC motors to implement the motor 156.

Claims

1. A dishwasher, comprising: a washing fluid conduit system comprising a plurality of washing fluid supply conduits, each washing fluid supply conduit 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 sump outlet being for a corresponding washing fluid supply conduit of the plurality of washing fluid supply conduits; a pump for pumping washing fluid from the sump to the washing fluid conduit system; a flow controller assembly operable to selectively enable washing fluid to flow from the sump to selected one or more washing fluid supply conduits, the flow controller assembly comprising: a flat circular flow diverter comprising a plurality of diverter orifices; 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 alignment between one or more diverter apertures and one or more corresponding sump outlets, thereby enabling washing fluid to flow from each of the one or more sump outlets aligned with the one or more diverter apertures to a 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, the plurality of cam elements including a reference cam element having an arc length that is different from the arc lengths of other cam elements of the plurality of cam elements; - 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 with a detection switch so as to switch the detection switch to a first state when the cam follower element mechanically interacts with the cam elements and to switch the detection switch to a second state when the cam follower element does not mechanically interact with the cam elements; a control unit configured to evaluate the position of the flow diverter among the predetermined diverter positions and to drive the motor in dependence on the evaluated position, wherein the control unit is configured to evaluate the position of the flow diverter by: - evaluating a position corresponding to a reference predetermined diverter position associated with the reference cam element of the predetermined diverter positions based on the duration of the interaction interval in which the detection switch is in the first state; -Evaluating a position corresponding to a predetermined steering position among the predetermined steering positions that is different from the reference steering position by counting the number of times the detection switch switches to a selected state between the first state and the second state after evaluating the reference steering position.

2. The dishwasher according to claim 1, wherein: The control unit is configured to store a counter indicating the position of the flow diverter among these predetermined diverter positions, and the control unit is configured to set the counter to a first value after assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position.

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

4. A dishwasher as claimed in any one of the preceding claims, wherein Each cam element of the plurality of cam elements that is different from the reference cam element has an arc length that is less than the arc length of the reference cam element.

5. The dishwasher according to 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 after assessing an interaction interval having a duration above a first threshold.

6. The dishwasher according to claim 5, wherein: The control unit is configured to assess that the flow diverter has reached the angular position corresponding to the reference predetermined diverter position after evaluating an interaction interval having a duration satisfying both: - is above the first threshold, and - is below a second threshold, said second threshold being higher than said first threshold.

7. The dishwasher according to claim 6, wherein: The control unit is configured to generate a warning indicating that the flow diverter is in an invalid position after evaluating at least one of the following: - an interaction interval having a duration higher than said second threshold, - an interaction interval having a duration below a third threshold, said third threshold being lower than said first threshold.

8. The dishwasher according to claim 6 or claim 7, wherein: The value of the second threshold value depends on the arc length of the reference cam element.

9. The dishwasher according to any one of claims 5 to 8, wherein: The value of the first threshold depends on an arc length of a cam element of the plurality of cam elements that is different from the reference cam element.

10. A dishwasher as claimed in any one of the preceding claims, wherein The cam elements of the plurality of cam elements that are different from the reference cam element all have the same arc length.

11. A dishwasher as claimed in any one of the preceding claims, wherein The motor is configured to rotate the flow diverter at a constant rotational speed when driven by the control unit.

12. A dishwasher as claimed in any one of the preceding claims, wherein Each cam element projects parallel to the axis of rotation of the flow diverter.

13. A dishwasher as claimed in any one of the preceding claims, wherein The control unit is configured to generate a fault warning indicating a fault in the motor and / or the cam follower system if a timeout expires before a new transition of the detection switch is evaluated after the motor is switched on.

14. A dishwasher as claimed in any one of the preceding claims, wherein The control unit is configured to: - receiving an indication of a target predetermined steering position among the predetermined steering positions; - driving the motor to rotate the flow diverter until the flow diverter has been assessed to have reached an angular position corresponding to said target predetermined flow diverter position.

15. The dishwasher according to claim 14, wherein The control unit is configured to: - switching off the motor when the flow diverter has been assessed to have reached an angular position corresponding to said target predetermined diverter position; - turning on the pump, thereby causing washing fluid to flow from each of the one or more sump outlets aligned with the one or more diverter apertures to a corresponding washing fluid supply conduit.

16. The dishwasher according to claim 14 or 15, wherein: The indication of a target predetermined diverter position among the predetermined diverter positions is dependent upon the phase of the selected wash cycle being performed by the dishwasher.

17. A dishwasher as claimed in any one of the preceding claims, wherein The control unit is configured to perform the following operations when the dishwasher is powered on: If the detection switch is evaluated as being in the first state, driving the motor until the detection switch is evaluated as changing to the second state.

18. A dishwasher as claimed in any one of the preceding claims, wherein The positioning system further comprises a driver module configured to: - generating a motor drive signal based on a control signal generated by the control unit; - providing a motor drive signal to the terminals of the motor, in: The detection switch comprises a first electrical terminal electrically coupled to a terminal of the motor and a second electrical terminal electrically coupled to an input of the control unit for providing a sensing signal indicative of a state of the detection switch.

19. The dishwasher of claim 18, wherein: - when the detection switch is in the first state, the first electrical terminal is electrically coupled to the second electrical terminal; When the detection switch is in the second state, the first electrical terminal is electrically disconnected from the second electrical terminal.

20. The dishwasher according to claim 18 or 19, wherein: The driver module and the control unit are powered by a DC supply voltage.

21. The dishwasher according to claim 20, wherein: The DC power supply voltage is lower than 20 volts.

22. A dishwasher as claimed in any one of the preceding claims, wherein The positioning system further includes a cam support member coaxially coupled to the flow diverter, the cam member being located on the cam support member.

23. A dishwasher as claimed in any one of the preceding claims, wherein The components of the dishwasher include at least one of the following: -Dishwasher spray arms; -Dishwasher detergent dispenser; - a filter for the sump; -Dishwasher tanks; -Dishwasher heat exchangers.

24. A method for operating a dishwasher, comprising: - selectively enabling wash fluid to flow from the dishwasher sump to selected one or more wash fluid supply ports of the dishwasher wash fluid conduit system The catheter, said selectively enabling comprising: - rotating a flat circular flow diverter relative to a sump outlet of the sump through a plurality of predetermined diverter positions, each sump outlet corresponding to a corresponding washing fluid supply conduit, each diverter position providing alignment between one or more diverter apertures on the flow diverter and one or more corresponding sump outlets, thereby enabling washing fluid to flow from each of the one or more sump outlets aligned with the one or more diverter apertures to the corresponding washing fluid supply conduit, wherein a plurality of cam elements are 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, the plurality of cam elements including a reference cam element having an arc length that is different from the arc lengths of other cam elements of the plurality of cam elements; evaluating a position of the flow diverter among the predetermined diverter positions by a cam follower system comprising a cam follower element configured to mechanically interact with the cam elements and with a detection switch so as to switch the detection switch to a first state when the cam follower element mechanically interacts with the cam element and to a second state when the cam follower element does not mechanically interact with the cam element, said evaluating said position of the flow diverter comprising: - measuring the duration of one or more interaction intervals during which the detection switch is in the first state; - evaluating a position corresponding to a reference predetermined diverter position associated with the reference cam element, of the predetermined diverter positions, based on said measured duration of said one or more interaction intervals; - counting the number of times the detection switch transitions to a selected state between the first state and the second state after evaluating the reference diverter position, and - evaluating a position corresponding to a predetermined diverter position different from the reference diverter position among the predetermined diverter positions based on the counted number of times.

25. The method of claim 24, further comprising: After assessing that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position, setting a counter indicating the position of the flow diverter among the predetermined diverter positions to a first value.

26. The method of claim 25, further comprising: - updating the value of the counter each time the detection switch is switched to the selected state after evaluating the reference predetermined diverter position.

27. The method of any one of claims 24 to 26, wherein Each cam element of the plurality of cam elements that is different from the reference cam element has an arc length that is less than an arc length of the reference cam element, the method further comprising: - evaluating that the flow diverter has reached an angular position corresponding to the reference predetermined diverter position after evaluating an interaction interval having a duration above a first threshold.

28. The method of claim 27, further comprising: - evaluating that the flow diverter has reached the angular position corresponding to the reference predetermined diverter position after evaluating an interaction interval the duration of which satisfies both: - is above the first threshold, and - is below a second threshold, said second threshold being higher than said first threshold.

29. The method of claim 28, further comprising: - A warning indicating that the flow diverter is in an invalid position is generated after evaluating at least one of the following: - an interaction interval having a duration higher than said second threshold, - an interaction interval having a duration below a third threshold, said third threshold being lower than said first threshold.

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