Detergent dispenser for dishwasher

Abstract

A detergent dispenser for a dishwasher comprises a dispenser body (20) having a front portion at which is defined a container (40) delimited by a plurality of walls (40a-40d) for containing a detergent (LD). The dispenser (1) comprises a sensor device (50) having a sensitive portion configured to detect an electrical capacitance. The sensitive portion comprises a single detection electrode (Jd) arranged outside the container (40) in a side-by-side position with respect to a first wall (40b) of the plurality of walls (40b-40d) defining the container (40). The sensor device (50) comprises a control circuit (MC) to which the single detection electrode (Jd) is connected in a signal communication manner, the control circuit (MC) being configured for detecting the presence and / or type of detergent present in the container (40) as a function of a first value representative of an electrical capacity between the single detection electrode (Jb) and the detergent present in the container (40).

Description

Technical Field

[0001] The present invention relates to a detergent dispenser for a dishwasher and has been developed with particular attention paid to a dispenser equipped with a sensor device for detecting the type of detergent loaded into the dispenser itself. Background Art

[0002] Some dishwashers are equipped with a dispensing device configured to dispense at least one detergent. Typically, these devices are designed to dispense at least two different detergents, usually represented by a cleaning agent (in powder, liquid or tablet form) and a liquid rinse aid, at different times in the same wash cycle of the dishwasher. Dispensers designed to dispense a single washing substance in solid or liquid form are also known.

[0003] In the most common solution, the dishwasher dispenser comprises a dispenser body associated with one of the vertical walls delimiting the washing tank of the machine (including the inner shell of the machine front door facing the inside of the washing tank), usually recessed at least partially in a sealing manner in an opening provided in this wall. In the front area of ​​the dispenser body, a container is defined for containing the detergent, which is usually in powder form, tablet form or fluid form (liquid or gel) required to perform the washing cycle. The dispenser body has a movable door associated with it at the container. An elastic device operates between the dispenser body and the door body, which pushes the door to the corresponding open position, as well as a door locking / release system. During the washing cycle, the opening of the above-mentioned door is appropriately controlled by the programmer or timer of the dishwasher, which controls an actuator that is part of the above-mentioned locking / release system; the latter is also usually designed to enable manual opening and closing of the door in the case where the machine is not running.

[0004] As mentioned above, detergents that can be used in dishwashers can be of different types, such as liquid form, or powder form, or compressed tablet form, or even tablet or capsule form (also called "tablets" or "pods"), in which one or more liquid or semi-solid detergents are encapsulated in a shell formed by a water-soluble film (usually a polymer, such as polyvinyl acetate PVA).

[0005] Since these different types of detergents have different properties, it may be convenient to optimize the treatment programs that the dishwasher can perform according to the type of detergent actually used. In other words, a treatment program designed for a powder detergent may not be completely suitable for the use of a liquid detergent or in tablet form. Therefore, in some known solutions, the type of detergent used is detected from time to time so that the dishwasher control logic can select a program or at least one program parameter that is considered to be most suitable for the detected type of detergent.

[0006] Whatever the type of detergent, even simply detecting its presence in the corresponding container may be useful, for example if the control logic of the dishwasher is programmed to prevent the execution of a washing program if no detergent is detected in the container itself (e.g. due to the user's forgetfulness).

[0007] In some solutions, the detection is performed after the container door is opened, i.e. after the detergent has (in theory) been dispensed into the tank of the machine. In these solutions, the presence (or absence) and / or type of detergent is usually identified by a sensor device that detects one or more characteristics of the washing liquid (i.e. the water-detergent mixture) present in the tank. These characteristics may involve electrical quantities (e.g. conductivity), optical quantities (e.g. turbidity) or chemical quantities.

[0008] In other solutions, the detection of the detergent type takes place directly in the dispenser equipped with appropriate sensor means.

[0009] FR 2940037 A discloses a detergent dispenser provided with a receiving area for detergent, to which a capacitive sensor is associated. The sensor comprises two opposing electrodes arranged around the aforementioned receiving area and is designed to detect the presence and type of detergent contained in the area. More specifically, the two electrodes are arranged along two opposing walls delimiting the receiving area and in practice realize two electrically insulated metal armatures of a flat capacitor.

[0010] The capacitive detection proposed by FR 2940037 A is based on the fact that the equivalent capacity value of the detergent that may be present in the dispenser is proportional to its permittivity. On this basis, the proposed sensor can detect whether detergent is present in the receiving space between two electrodes and, if present, its type, which can be between powdered detergent, detergent in tablet form, liquid or gel detergent.

[0011] The solution described in FR 2940037 A is structurally complex since it requires that the receiving area for the detergent be arranged between two electrodes, with possible complications in terms of assembly, dimensions and electrical connections.

[0012] The capacitance measurements obtainable by the sensor according to FR 2940037 A may also be adversely affected by various factors, such as environmental stresses, such as temperature, humidity, aging, electronic / electromagnetic noise, resulting in poor reliability, especially in the long term. Furthermore, possible water residues in the above-mentioned receiving area after a previous washing cycle in the dishwasher may also be a source of detection errors. Summary of the invention

[0013] In summary, the present invention aims to solve one or more of the above mentioned drawbacks. In this context, the present invention aims to obtain a dispenser equipped with a capacitive sensor device suitable for detecting the presence and / or type of detergent, having a simple and economical structure, and operating accurately and reliably.

[0014] According to the invention, this object and other objects, which will become clearer later, are achieved by a detergent dispenser having the features of the appended claims. The objects of the invention are also achieved by a method and a sensor device for detecting the presence and / or type of detergent in a container of a dishwasher dispenser, as well as by a dishwasher comprising such a dispenser or a dispenser comprising such a sensor device. The claims form an integral part of the technical teaching provided herein in relation to the invention.

[0015] According to a first embodiment of the present invention, a detergent dispenser for a dishwasher includes a dispenser body and a door.

[0016] wherein the dispenser body has a front portion defining a container for containing detergent, the container being bounded by a plurality of walls,

[0017] wherein the door is movably mounted on the dispenser body so as to be movable between a closed position and an open position of the container,

[0018] wherein the dispenser comprises a sensor device having at least one sensitive portion configured to detect electrical capacitance,

[0019] wherein at least one sensitive portion comprises at least one single detection electrode, which is arranged outside the container in an adjacent or side-by-side position relative to a first wall of a plurality of walls defining the container,

[0020] And wherein the sensor device includes a control circuit, to which the single detection electrode is connected in a signal communication manner, and the control circuit is configured to detect the presence and / or type of detergent present in the container based on a first value representing the capacitance between the single detection electrode and the detergent present in the container.

[0021] According to the invention, the definition "single electrode" refers to a first electrode or armature of a capacitive element that does not require a second opposing electrode; even in the case of multiple single electrodes, each first single electrode or armature does not require a corresponding opposing second electrode.

[0022] The capacitive sensor device has a structure that is simple, compact and easy to accommodate on the body of the dispenser, without the need to provide two distinct opposing detection electrodes, which obtain two armatures of the capacitor.

[0023] As will be seen, in fact, the proposed detection mode is able to detect the presence (or absence) and / or type of detergent based on electrodes which obtain a sensitive armature of the capacitor; the other armature can be defined as "virtual" since it is represented by the same detergent contained in the container.

[0024] In various embodiments, the distributor comprises at least one compensation device for compensating the first value representative of the capacitance. In this way, if necessary, it is possible to have a representative value of the capacitance compensated, for example, according to the environmental and aging conditions of the sensor device, as better explained below, with the aim of a higher detection accuracy.

[0025] The compensation device may include at least one reference electrode arranged in a non-adjacent or non-juxtaposed position relative to a wall of the plurality of walls defining the container and connected to the control circuit in a signal communication manner. In this way, the reference electrode is substantially subjected to the same environmental and aging conditions as the sensor device and is not affected by detergents.

[0026] Preferably, the control circuit is therefore configured to compensate the first value representing the capacitance according to at least one further value representing the capacitance acquired via at least one reference electrode. For this purpose, preferably, the control circuit is configured to perform a correlation and / or a differential measurement between the first value representing the capacitance and the further value representing the capacitance in order to obtain a compensated value representing the capacitance.

[0027] In various embodiments, the compensation means comprises a temperature detector. This solution is useful if one wishes to take into account the influence of temperature on the capacitive type detection.

[0028] In various embodiments, the control circuit is configured to compare the first value representative of the capacitance or the first compensated value representative of the capacitance with at least one corresponding reference threshold value to infer the presence and / or type of detergent contained in the container.

[0029] Preferably, the control circuit is configured to compare the first value representing the capacitance or the first compensated value representing the capacitance with a plurality of reference thresholds to infer a type of detergent that may be contained in the container, the type of detergent being between liquid detergent, powder detergent, tablet or capsule form.

[0030] In various embodiments, on the inner side of the first wall of the container, at least one spacing element is provided, which is suitable for holding the detergent in tablet form in a position spaced apart from the same inner side of the first wall. In this case, the tablet can be held in the container at a position further away from the single detection electrode than the detergent in bulk form (powder or liquid), thereby attenuating the first value representative of the capacitance: this makes it easier to distinguish between the tablet and the bulk detergent, in particular when the tablet is formed of a similar material to the bulk detergent.

[0031] Advantageously, the single detection electrode and the control circuit, preferably in the form of a microcontroller, are located on the same circuit support mounted on the dispenser body. In this way, the installation of the sensor device is further simplified. Furthermore, the compensation means (reference electrode and / or temperature detection) can be mounted on the circuit support to further facilitate the compactness of the sensor device when assembled in the operating position.

[0032] The possibility of obtaining at least one single detection electrode and at least one of the control circuit and the compensation means (at least one single reference electrode and / or temperature detector) on the same support enables easy assembly relative to a first wall of the walls delimiting the container.

[0033] In various embodiments:

[0034] the control circuit has at least one signal input to which the single detection electrode (or at least one reference electrode) is connected, the signal input being further connected or connectable to a circuit comprising a controllable switch (such as an electronic switch) and a capacitor, the controllable switch being switchable between a first position, in which the capacitor is connected to the voltage source, and a second position, in which the capacitor is connected to the at least one signal input, and

[0035] - The control circuit is configured to switch the controllable switch from a first position to a second position so as to discharge the capacitor in a manner proportional to a first value representing capacitance (or another value representing capacitance), wherein the first value (or the other value) is associated with at least one signal input terminal.

[0036] Thus, by means of a simple sampling circuit, in particular of the sample and hold type, a first value representative of the capacitance can be detected (and if compensation is provided, another value representative of the capacitance can be detected). Such a circuit - or any other technically equivalent circuit for the purpose of detecting capacitance - is usually implemented in a commercial microcontroller for which the control circuit is available.

[0037] Preferably, for more reliable detection, at least one single detection electrode has an area that affects only the lower or middle part of the container.The single detection electrode and the at least one reference electrode may be substantially coplanar.

[0038] In various embodiments, the sensor device further comprises an auxiliary control electrode located close to the single detection electrode, which is connected or selectively connectable to the control circuit, in particular in order to attenuate possible interferences caused by the presence of water residues in the container. This measure makes it possible to avoid detection errors when water residues are present in the container, for example, which were caused by a previous washing cycle performed by the dishwasher. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Further objects, features and advantages of the present invention will become apparent from the detailed description given below, with reference to the accompanying drawings, which are provided as non-limiting examples only, in which:

[0040] - Figure 1 is a schematic front perspective view of a detergent dispenser according to a possible embodiment, wherein the corresponding door is in a closed state;

[0041] - Figure 2 is a schematic rear perspective view, partially in section, of a detergent dispenser according to a possible embodiment;

[0042] - Figure 3 and Figure 4 is a schematic front perspective view of a detergent dispenser according to a possible embodiment at two different angles, wherein the corresponding doors are in an open state;

[0043] - Figure 5 is a schematic side perspective view, partially in section, of a detergent dispenser according to a possible embodiment;

[0044] - Figure 6 and Figure 7 are schematic perspective views of two possible forms of a sensor device for a detergent dispenser according to possible embodiments;

[0045] - Figure 8 and Fig. 9 is a schematic front perspective view of a detergent dispenser according to a possible embodiment, wherein a corresponding door is in an open state and two different detergents are contained in corresponding containers;

[0046] - Fig.10 is a schematic diagram intended to illustrate a first possible circuit arrangement and operating principle of a sensor device of a dispensing device according to a possible embodiment;

[0047] - Fig.11 is a schematic diagram intended to illustrate a second possible circuit arrangement of a sensor device of a dispensing device according to a possible embodiment;

[0048] - Figure 12-14 is with Fig.11 A similar diagram of different types of detergents; and

[0049] - Fig.15 and Fig.16 is a schematic diagram intended to illustrate another possible circuit arrangement and the corresponding operating principle of a sensor device of a dispensing device according to a possible variant embodiment. DETAILED DESCRIPTION

[0050] References to "an embodiment" in this description indicate that a particular configuration, structure, or feature associated with that embodiment is included in at least one embodiment. Thus, phrases such as "in one embodiment" may appear in different places in this description, but do not necessarily refer to the same embodiment. Furthermore, particular configurations, structures, or features may be combined in any suitable manner in one or more embodiments, even different from those depicted. The references used herein are for convenience only and do not limit the scope of protection or the scope of the embodiments.

[0051] First reference Figure 1-4 , reference numeral 1 denotes as a whole a detergent dispenser according to a possible embodiment of the invention. In the particular case illustrated, the dispenser 1 is intended for use in a dishwasher and is configured to be mounted on the wall of a corresponding washing tank, although this is not an essential feature. For example, the mounting wall may be defined by the inner shell of a dishwasher door, the dispenser 1 being fixed to the side of this shell facing the tank interior during operation of the machine.

[0052] The dispenser 1 comprises a dispenser body 20, which is preferably at least partially formed of a molded thermoplastic material. The body 20 is preferably configured to be at least partially recessed in an opening provided in the above-mentioned mounting wall. In the example shown, the body 20 has a generally quadrilateral outer contour, although this is not a necessary feature. With respect to the preferred orientation of the dispenser 1 in its operating position, the sides of the outer contour of the body 20 indicated by 20a and 20b are generally referred to herein as the "upper side" and the "lower side", as shown in FIG. Figure 1 and Figure 2 When mounted on a dishwasher door, side 20a will then be located at a higher position than side 20b when the door is closed.

[0053] The body 20 may comprise a front part or portion adapted to face the sink or to be located in the sink, and a rear part or portion adapted to be at least partially inserted into the above-mentioned opening of the mounting wall, the two parts being conveniently molded separately from each other in thermoplastic material and then joined together according to techniques known per se, for example by welding. The two parts may define at least one body 20 between them.

[0054] In this example, the front part of the body 20 defines the front of the dispenser 1, the front of which is intended to face or be located in the sink and has at least one door associated therewith, as a whole represented by 30. In this example, the door 30 is a door that slides in a direction substantially transverse or perpendicular to the two sides 20a and 20b (schematically indicated by the arrow X in Figure 1 ). However, this is not an essential feature, because according to other possible embodiments, the door 30 can be made to slide in a direction perpendicular or inclined with respect to said direction or arrow X, or it can be hinged to the body 20 so as to be able to perform an angular displacement, for example in the form of a folding door (in this case, the axis of rotation of the door can be substantially parallel to the sides 20a - 20b), or in the form of an angular sliding door, i.e., slidable in a curved direction (in this case, the axis of rotation of the door can be substantially parallel to the depth dimension of the body 20, indicated by the arrow Z in Figure 1 ), all of which are according to known techniques.

[0055] Returning to the non - restrictive example depicted, the door 30 can follow a substantially linear or at least partially arched path. For this purpose, a sliding zone A ( Figure 1 ) is identified on the front of the body 20, in which the door 30 is constrained to slide. In this zone A, a tray or container is defined, represented by 40 in Figure 3-4 , suitable for containing detergents, such as detergents in powder form, detergents in tablet or capsule form, or detergents in fluid form (liquid or gel).

[0056] As can be seen from Figure 3-4 , the container 40 is substantially obtained from a recess in the front of the dispenser 1, which has a rear wall 40a, two opposite first side walls 40b and 40c, and two opposite second side walls, only one of which is visible, represented by 40d. The container 40 has an opening, which is usually opposite the bottom 40a, i.e., an opening for loading and dispensing the detergent.

[0057] In various preferred embodiments, at least one spacer and / or positioning element is provided inside the container 40, which is configured to hold detergents in solid form (usually tablets or capsules filled with washing liquid or gel) in a position substantially spaced apart from at least one wall of the container itself. At least one spacer or positioning element can be provided on the inner side of each wall defining the container 40, although the presence of at least one spacer element on a single wall may be sufficient (especially the wall facing the sensor device, which will become clear later).

[0058] In Figure 3-4 's non - restrictive example, at least one spacer element 41 is provided for the side wall 40b (refer to Figure 3-3, on the right) and at least one spacing and / or positioning element 42 for the rear wall 40a (the element 41 shown extends between the side wall 40b and the rear wall 40a, while the spacing and / or positioning elements 42 shown each extend between the side wall 40d and the rear wall 40b).

[0059] It is conceivable that if a dose of powdered or liquid detergent is introduced into the container 40, the detergent itself will fill a corresponding part of the volume of the container 40, coming into contact with the walls 40a-40d delimiting the container; this situation is Figure 8 Schematically shown in FIG. 4 , wherein a container 40 contains a dose of a liquid detergent LD (but it may be a detergent in a gel or powder form). On the other hand, if a detergent tablet or capsule ST is placed in the container, as shown in FIG. Fig. 9 As shown, it will be spaced apart from the wall or walls provided with at least one spacing element 41. Note that for greater clarity, Figure 8-9 , the container 40 is intentionally shown with the door 30 open.

[0060] Still referring to the non-limiting example shown, the door 30 has a corresponding body, for example formed by molding a thermoplastic material, which can be the same material as that constituting the body 20, for example polypropylene filled with a reinforcing material such as talc or glass fiber. The door 30 can slide on the body 20 in a guided manner in a sliding zone A, so that it can be moved between a closed position and an open position of the container 40, respectively. Figure 1 and Figure 3-4 For this purpose, guiding or restraining means are operatively provided between the body 20 and the door body 30 , which in this example comprise sliding guides (not shown) obtained according to a technique known per se.

[0061] Reference Figure 1 and Figure 3-4, in the example shown, next to zone A of the body 20 is associated a cover 2 equipped with a corresponding manually operable coupling / releasing device 2a. The cover 2 is preferably hinged to the dispenser body 20 so as to rotate according to a substantially horizontal axis, but it can be mounted slidably. The cover 2 is intended to cover a corresponding area at the front of the dispenser 1, where the inlet of the invisible tank for the second detergent, in particular a liquid detergent additive, such as a rinse aid, is located. In the same area opposite to the cover 2, there may also be an outlet forming part of the liquid additive dispensing system, and for this purpose, the body of the cover 2 preferably has an opening or a channel to allow such a liquid additive to flow into the washing tank of the machine, not shown here. As mentioned above, in this exemplary description, it is assumed that the dispenser 1 is fixed to a wall delimiting said tank, in particular a wall defined by a dishwasher door, so that in the closed state of the door, the upper side 20a of the peripheral contour of the body 20 extends higher than the lower side 20b: in this way, during operation of the machine, the body 20 is oriented substantially vertically, facilitating the outflow of detergent towards the inside of the tank. The presence of the above-described liquid additive dispensing system and its trough and cover 2 is not necessarily relevant to the embodiment of the invention, and these components may also be omitted.

[0062] According to a technique known per se (see, for example, US5884821 A, the teaching of which in this respect is considered to be incorporated herein), the door 30 is preferably urged to a corresponding open state of the container 40 by invisible elastic means, which elastic means comprises, for example, a spring constrained between the body 20 and the door 30. Preferably, between the body 20 and the door 30, a locking / releasing system of the door is also operable, which system can be controlled by a not shown dishwasher programmer or manually controlled. In various embodiments, the system comprises a coupling member 3a arranged in zone A, for example in Figure 1 The coupling member 3a is intended to cooperate with a (not visible) retaining element provided on the door 30 and may, for example, comprise or have an associated rotation axis 3a' ( Figure 2 ), the rotation axis passes through the dispenser body 20 and can be driven by an actuator system 4 ( Figure 2 )operate.

[0063] In various embodiments, the locking / release system of the door 30 further includes a button. Figure 1 denoted by 3b, which is carried by the door 30 and can be manually operated by the user according to a technique known per se; the button 3b can be operably associated with a manual release mechanism, which is also carried by the door 30 and comprises the above-mentioned retaining element. The presence of the button 3b and the associated mechanism 3c is only optional, since the manual switching function of the coupling / release system can be obtained directly from the member 3a, for example by equipping such a member with a manually operable lever to rotate it, and wherein when the door 30 is in the closed position, the lever (e.g. Figure 1 The door 30 (shown) at least partially protrudes outside the door 30 so that it can be accessed by a user (see the above-mentioned US5884821 A, the teachings of which in this regard are deemed to be incorporated herein).

[0064] The dispenser 1 of the present invention is equipped with a capacitive sensor device configured to detect the presence and / or type of detergent present in the container 40. In a possible embodiment, the sensor device is Figure 2 Schematically shown in FIG. 5 , wherein the entirety of the sensor device 50 is indicated. In the illustrated case, the sensor device 50 is mounted in a cavity defined in the dispenser body 20, at a position generally adjacent to the outer surface of the container 40, in particular Figure 3 The outer surface of the side wall is represented by 40b.

[0065] The rear part of the dispenser body 20 can be shaped so as to obtain at least a portion of the above-mentioned groove for the above-mentioned second detergent (not visible in the figure), which groove does not extend into the area defining the container 40. By the way, in a different embodiment, the rear part of the dispenser body 20 can be shaped so as to produce such a groove, which also extends in the area of ​​the container 40, for example the wall of the rear part is arranged between the sensor device 50 and the corresponding side wall of the container 40.

[0066] The sensor device 50 has at least one sensitive portion configured to detect electrical capacitance. According to one aspect of the invention, the at least one sensitive portion comprises at least one single detection electrode, which is positioned outside the container 40 in an adjacent or side-by-side position relative to one of the multiple walls defining the container, and the control circuit of the sensor device (to which the at least one single detection electrode is connected in signal communication) is configured to detect the presence and / or type of detergent present in the container based on a first value representing the electrical capacitance between the at least one single detection electrode and the detergent present in the container.

[0067] In other words, the sensor device uses a configuration in which a single detection electrode (such as a single measuring electrode) does not require a corresponding second opposing electrode as in the case of the prior art, because the same detergent obtains a kind of "virtual" electrode. Therefore, even in the case of multiple single measuring electrodes, each single measuring electrode does not require a corresponding opposing second electrode.

[0068] In the case where the sensor device 50 provides a compensation function, the device itself may also include at least one single reference electrode, which does not require a corresponding second counter electrode. Also in this case, the presence of multiple single reference electrodes can be foreseen, each of which does not require a corresponding second counter electrode.

[0069] Also refer to Figure 5In the non-limiting example shown, the sensor device 50 comprises a single detection electrode Jd and a single reference electrode Jr, both of which are arranged outside the container 40.

[0070] The single detection electrode Jd is placed in an adjacent or side-by-side position relative to one of the walls defining the container 40 , while the reference electrode Jr is placed in a non-adjacent position or non-side-by-side arrangement relative to any of the walls defining the container 40 .

[0071] As described above, in the example shown, the electrode Jd is disposed relative to the side wall 40b ( Figure 3 ) are arranged adjacent to or side by side, but in other embodiments, the sensor device 50 can be installed in such a manner that the electrode Jd can be arranged adjacent to or side by side with respect to any other wall defining the container 40.

[0072] Preferably, the electrode Jd has such an area and operating position that its electric field affects only the lower area of ​​the container 40, or in any case the area occupied by detergent (if detergent is actually present). This is to prevent the electrode Jd from also performing measurements in the upper area of ​​the container, which may be free of detergent and which would in this case distort the measurements (generally, it is considered that the dose of concentrated detergent does not correspond to the entire volume of the container, but only to a part of it). However, in other embodiments, at least one detection electrode Jd can also affect other parts of the container 40 and be configured to perform detection in both the lower and upper areas of the container, for example. The case involving the use of a sensor device with multiple sensitive parts is not excluded from the scope of the present invention, each sensitive part comprising a corresponding single detection electrode Jd located in a position next to the same wall of the container 40, wherein each single detection electrode operates according to the logic described herein (and therefore each single detection electrode is able to perform its own detection independently of the detection of the other one or more detection electrodes provided).

[0073] In a preferred embodiment, the sensor device 50 comprises at least one electrically insulating substrate, which obtains a preferably flat and relatively thin circuit support, such as a printed circuit board. The support can be formed of a material suitable for obtaining a printed circuit, such as FR4 or a similar composite material (such as fiberglass), or even of a ceramic or polymer-based material, preferably a moldable material.

[0074] In the preferred example depicted, a single support, indicated by 51, is provided, which carries thereon the electrodes Jd and Jr. On the support 51, for example in the middle region of the two electrodes Jd and Jr, additional components may also be associated, such as a control circuit MC of the device, in particular implemented by an electronic controller, and associated electrical conductor elements and terminals for external electrical connection of the sensor device 50. The circuit or controller MC may be, for example, a microcontroller or an ASIC chip. The circuit or controller MC preferably comprises at least one processing and / or control logic unit, one memory circuit and inputs and outputs, including analog / digital inputs.

[0075] Figure 6 A possible embodiment of a sensor device 50 is shown. As mentioned above, the electrodes Jd and Jr are connected to respective inputs of a circuit or controller MC via conductors in the form of conductive tracks Ld and Lr present on the support 51 .

[0076] Additional tracks may be connected to additional inputs and outputs of the circuit or controller MC, such as two tracks for power supply and at least one track for signal output (indicated by reference numerals but not shown), which tracks define corresponding terminals T1 at the far end for external connection of the device 50.

[0077] The electrodes Jd and Jr are formed of a conductive material, such as a metallic material or a metal alloy, and are associated with the front or rear of the support 51. The electrodes Jd and Jr may be in the form of a plate or foil, for example, applied or engraved on the support 51, or consist of a conductive layer, similar to the tracks Ld and Lr, deposited on the support 51, for example via screen printing or similar techniques.

[0078] The compensation device equipped with the sensor device 50 may include at least one temperature sensor for the functions explained below. Figure 6 In the illustrated case, the temperature sensor is denoted by TS and is arranged on the support 51 and is also connected to a corresponding conductive track having a corresponding connection terminal T2 at the far end. The temperature sensor TS (when provided) can be, for example, an NTC thermistor. Alternatively, the temperature sensor TS can be connected to the circuit or controller MC, such as Figure 7 shown.

[0079] The terminals T1 and / or T2 are preferably substantially flat, for example made by appropriate shaping of conductive tracks of a printed circuit board (PCB) constituting the support 51; alternatively, additional electrical connection elements may be soldered on the terminals T1 and / or T2. The terminals T1 and / or T2 (and / or any additional electrical connection elements) are preferably arranged to obtain corresponding electrical connectors, in particular for connecting the sensor device 50 to other electrical parts of the dispenser 1 and / or to a dishwasher control unit.

[0080] In other embodiments, the circuit or controller MC is not arranged on at least one support 51 of the sensor device, and the control circuit of the device itself is either located remotely in the dispenser 1 or implemented in the dishwasher control system. Therefore, for this case, on the support 51, only the electrode Jd, possibly also the electrode Jr and / or the temperature sensor TS, and the corresponding conductive tracks and terminals and / or connectors are provided for electrical connection to the electronic circuit at the remote location.

[0081] The sensor 50 is preferably interfaced to an external control system, such as a dishwasher control board, via a connector obtained by terminal T1 (and possibly a connector obtained by terminal T2). For this purpose, the circuit or controller MC is designed for data transmission, preferably via a pulse width modulated signal (PWM); however, other transmission systems may be employed, such as a serial format, such as an interface and / or a single edge nibble transmission (SENT) protocol. The signal sent by the circuit or controller MC may include information representing the presence and / or type of detergent, such as a liquid or powder detergent or a tablet or capsule, and / or information representing the presence of an abnormal operating condition, such as for the purpose of warning and / or status signaling (e.g., the absence of detergent in the container 40 after the start of a washing cycle involving the use of detergent, and / or the presence of detergent in the container 40 other than the detergent specifically designed for the selected washing cycle, and / or the abnormal presence of detergent in the container 40 even after the washing cycle, as a powder detergent solidified due to moisture).

[0082] In various embodiments, an auxiliary control electrode may be provided, which is substantially adjacent to or at least partially surrounds the single detection electrode. Figure 6 In this case, such an auxiliary electrode is denoted by Jn, and the detection electrode Jd is in the area of ​​the support member 51 substantially surrounded by the electrode Jn.

[0083] The auxiliary control electrodes Jn are also connected to the terminals of the circuit or controller MC via respective conductive tracks Ln. The same electrodes Jn may be obtained from tracks of conductive material which preferably almost completely surround the electrode Jd, for example in a similar manner to the tracks Ld and Lr, the dimensions of which may be greater than the width of the tracks Ld, Lr.

[0084] Figure 7 The design of the sensor device 50 is similar to Figure 6 The device is different in that the detection electrode Jd has a larger extension area, and therefore the auxiliary control electrode Jn (when present) is also correspondingly larger. Figure 7 In this case, the temperature sensor TS is directly connected to the circuit or controller MC via corresponding conductive tracks.

[0085] In various embodiments, in the same circuit support 51, a first portion 51a and a second portion 51b can be identified, the first portion 51a being designed to be at least partially substantially close to a wall of the container 40 (here the wall 40b), and the second portion 51b being designed not to face any wall of the container 40, for example, also in Figure 5 When reference electrodes are provided, the first portion 51a of the support 51 has associated therewith at least one detection electrode Jd, while the second portion 51b has associated therewith at least one reference electrode JR.

[0086] In the example shown, a single circuit support 51 is provided, in which portions 51a and 51b are defined and to which both electrodes Jd and Jr are associated, and also comprising a circuit or controller MC. However, in a possible less advantageous variant embodiment, several separate circuit supports can be provided, interconnected by suitable electrical and possibly mechanical interconnection means, for example at least one circuit support corresponding to portion 51a and at least one circuit support corresponding to portion 51b, with conductors and / or electrical connectors to connect the conductive tracks of a support to the conductive tracks of another support. A circuit support can also be provided for the circuit or controller MC, or the latter can be placed on a circuit support carrying at least one of the electrodes Jd or Jr.

[0087] In the example shown, the electrodes Jd and Jr are located on the same main face of the support 51, opposite to the main face of the support 51 facing the container 40, but this is not an essential feature. In fact, in other embodiments, the electrodes Jd and Jr can be on a main face of the support 51 that directly faces the wall of the container 40. For these embodiments, it may also be advantageous that certain larger components of the device 50, such as the circuit or controller MC and / or the temperature sensor TS (if any), are located on a main face of the support 51 that is opposite to the main face where the electrodes Jd and Jr are located (in these embodiments, the electrical connection elements for connecting the electrodes to the circuit or controller MC may, for example, consist of metallized through-holes on the support 51): in this way, at least the detection electrode Jd can be closer to the relevant wall of the container 40 and directly facing it. It is also possible to provide the electrodes Jd and Jr, respectively, on two different main faces of the support 51.

[0088] from Figure 5As can be seen in the figure, the detection electrode Jd is in a position substantially beside the corresponding wall (here the wall 40b) of the container 40. As mentioned above, the electrode Jd may directly face the wall, or a corresponding part of the support 51 made of electrically insulating material and / or other parts made of electrically insulating material of the body of the dispenser 20 may be found between the wall and the electrode Jd. In any case, the electrode Jd is located relatively close to the above-mentioned wall of the container.

[0089] On the other hand, when a reference electrode Jr is provided, it is in a position spaced apart relative to the walls delimiting the container 40, i.e. it is not located adjacent to or beside any of said walls and it is therefore in a position further away than the detergent that can be accommodated in the container 40. As will be seen, this is because the electrode Jr is used, for example, to provide a reference value used (essentially for compensation purposes) during the detection of the presence and / or type of detergent performed via the electrode Jd.

[0090] As can be seen, the sensor 50 comprises capacitive elements, each of which comprises a single electrode Jd or Jr. As mentioned above, the term "single" here means that each electrode Jd and Jr belongs to a capacitive element which does not necessarily have to have a corresponding substantially facing additional electrode, such as a flat capacitor provided in FR 2940037 A. In other words, in the solution proposed herein, the detection electrode Jd obtains the sensitive armature of a "virtual capacitor", the other armature of which is obtained by the detected medium present in the container 40, and wherein at least the insertion wall (40b) of the container 40 (and any possible other part of the body 20) constitutes at least part of the dielectric or insulator between the armatures of this virtual capacitor, to which may be added a circuit support 51 (if the electrode Jd does not directly face said wall, as in Figure 5 a dielectric or insulator consisting of (in the case of a dielectric body) or air, as described below.

[0091] In practice, the electrode Jd together with the corresponding control electronics obtains a capacitive sensor having at least one single electrode capable of detecting the presence of detergent inside the container 40 even without being in direct contact with it.

[0092] Furthermore, as will be seen, the sensor device 50 that equips the dispenser according to the invention is advantageously capable of detecting the type of detergent, preferably distinguishing at least between liquid detergent, powder detergent, tablets or capsules containing detergent.

[0093] This operation is based on the principle of detection of the capacitance of a capacitor: the electrode Jd is the sensitive side of the capacitor and constitutes its armature, while the possible presence of a conductive medium in the vicinity (such as detergent) obtains the other armature of the capacitor. Thus, the presence or absence of a conductive medium in the vicinity of the electrode Jd determines the capacitance that the control electronics MC is able to detect and measure.

[0094] Therefore, in the application considered herein, the electrode Jd may obtain at least two different capacitance structures depending on whether detergent is present in the container 40, and specifically, at least:

[0095] a first capacitive structure having a first value representative of the capacitance when the electrode Jd is at least partially surrounded by detergent in the container 40, wherein the value is generally proportional to the type of detergent and / or the distance of the detergent from the electrode Jd, and

[0096] - a second capacitive structure having a second value representative of the capacitance when the electrode Jd is not surrounded by detergent in the container 40 .

[0097] The circuit or controller MC is substantially designed to distinguish between at least the above-mentioned first and second values ​​representing the capacitance, the value representing the capacitance associated with the electrode Jd, and thus to recognize at least the presence of detergent in the container 40 .

[0098] The circuit MC is preferably a digital electronic microcontroller equipped with an analog-to-digital converter. However, please note that the functionality of the circuit MC can be implemented at least partially via dedicated external circuits: for example, in a preferred embodiment, the circuit MC consists of a microcontroller implementing an analog-to-digital converter module, but in other embodiments, the controller MC can include a microcontroller (or a microprocessor or an ASIC or FPGA integrated circuit) and an integrated circuit dedicated to implementing the analog-to-digital converter functionality (either external or independent).

[0099] Microcontrollers suitable for the applications described herein are commercially available.

[0100] Figure 6-7 A circuit or controller MC is shown in schematic form, by way of example only, comprising at least two signal inputs to which the electrodes Jd and Jr are connected in a single configuration (ie not connected in common or in parallel with other electrodes) via corresponding conductive tracks Ld and Lr.

[0101] In a preferred embodiment, the detection of the value of the capacitance at the above-mentioned input terminals (hereinafter referred to as INd and INr) of the representative circuit or controller MC is performed indirectly, based on the measurement of the voltage. In this case, preferably, the input of the MC controller is an analog input and the controller itself implements or has an associated analog-to-digital converter.

[0102] Fig.10 A possible control circuit of a sensor device 50 associated with a respective wall 40b of a container 40 is illustrated in a partial and schematic manner. In this example, each input of interest (here represented by INd and INr) of the circuit or controller MC is associated with a sampling circuit or sample and hold comprising a controllable switch SS and a capacitor C HOLD , also identified here as sampling switch and sampling capacitor. The controllable switch SS can be switched between a first position and a second position. In the first position, the sampling capacitor C HOLD is connected to a voltage source V DD , in the second position, the same capacitor is connected to the corresponding electrode Jd or Jr. Preferably, the voltage is a DC voltage, such as a supply voltage of the circuit or controller MC (e.g. 5V). The circuit or controller MC has means for switching the controllable switch from the first position to the second position so as to control the sampling capacitor C in proportion to the capacitance value associated with the corresponding electrode Jd or Jr. HOLD Furthermore, when the controllable switch SS is in its second position, the circuit or controller MC has means for determining a voltage at the input INd or INr, which voltage is indicative of a capacitance associated with the electrode Jd or Jr. The circuit or controller MC then has comparator means for comparing a value representative of the voltage determined at least at the input INd with at least one relative reference threshold value or at least two reference threshold values, in order to infer whether the electrode Jd is surrounded by detergent contained in the container 40.

[0103] exist Fig.10 In the example of FIG. 1 , the sampling of the input terminals INd and INr is performed using respective sample and hold circuits associated with the corresponding analog-to-digital converters ADC. When the switch SS is in its second position, the capacitor C HOLD The charge balance is essentially determined between the capacitance of the capacitor C and the capacitance associated with the electrode Jd or Jr; in other words, by this charge balance, the capacitor C HOLD The charge of the capacitor C is thus determined by means of the converter ADC. HOLD The residual voltage is then compared with a predefined reference threshold in order to infer whether the electrode Jd faces the detergent or not, or whether the electrode Jd presents the above-mentioned first capacitance structure or configuration or the second capacitance structure or configuration.

[0104] According to the capacitor C HOLDThe above balance between the charges of the capacitor and the electrode Jd, the value representing the voltage at the capacitor end and / or the input terminal INd may be substantially consistent, or may be greater than or less than a certain reference threshold stored in the controller MC. For example, in one embodiment, the controller MC may be programmed so that a value representing a voltage equal to or higher than a predefined threshold is detected at the input terminal INd, indicating the fact that the detergent contained in the container 40 is aligned with the electrode Jd, while a value representing a voltage lower than the threshold is detected at the input terminal INb, indicating the fact that no detergent is aligned with the electrode Jd. Fig.10 In FIG. 1 , the dashed box denoted by VE is intended to schematically represent the function of a "virtual" electrode or armature obtained by the detergent, as described above, and FL schematically represents the electric field lines associated with the detection electrode Jd.

[0105] It should be understood that reference Fig.10 The described functionality can also be obtained by means of circuits different from but technically equivalent to those illustrated.

[0106] exist Fig.11 In the example shown, analog inputs INd and INr of the circuit or controller MC are connected to a multiplexer MTP which operates essentially as an electronic switch with associated therewith a single sampling or sample and hold circuit comprising a sampling capacitor C HOLD and sampling switch SS. Also in this case, switch SS can be connected to voltage V DD and a second position for connection to the output of the multiplexer MTP, ie a position connected to the electrodes Jd and Jr.

[0107] The input terminals INd and INr and the electrodes Jd and Jr are connected sequentially or alternately to the switch SS via the multiplexer MTP. The switch SS operates in a synchronized manner on the capacitor C HOLD The circuit switches between a first position of the charge and a second position in which the same capacitor is connected to the input INd or INr selected at the time of the multiplexer MTP and then connected to the corresponding electrode Jd or Jr. As described above, when the detergent is in front of the electrode Jd, the electrode Jd has a first value representing the capacitance associated with it, otherwise it has a second value representing the capacitance associated with it.

[0108] The described operating principle depends to some extent on environmental or common mode stresses (temperature, humidity, aging, electronic noise, etc.). Therefore, in various preferred embodiments, the controller MC is programmed to perform measurements taking into account reference values ​​or compensation values, for example by performing differential type measurements using at least one reference electrode Jr for this purpose.

[0109] Since environmental stresses are represented by a deviation in the measured value of the voltage value determined at the input of the controller MC, by performing correlation and / or differential measurements between representative values ​​obtained by at least one detection electrode Jd and at least one reference electrode Jr, it is possible to deduce the measured value on the detection electrode Jb and subtract the common mode effects present thereon, thereby eliminating any drift caused by environmental conditions (including aging of the system).

[0110] For this purpose, as described above, the sensor device 50 may include at least one detection electrode Jd at a location next to the wall of the container 40 so that the corresponding electric field FL can be affected by detergent that may be present in the same container. Preferably, the sensor device also includes at least one reference electrode Jr, which is placed relatively close to the single detection electrode Jd so as to be affected by the same environmental or common mode conditions (such as temperature, humidity, aging, electronic noise, etc.), but is relatively far from the container 40 so that its electric field is not affected by detergent that may be present in the container.

[0111] Therefore, the electrodes Jd and Jr cannot realize two armatures of the same capacitor.

[0112] The two electrodes Jd and Jr may have the same measurement area in order to have the same type of response to the above-mentioned environmental or common mode stress. As mentioned above, the electrodes Jd and Jr may be located substantially in the same plane, as in the example shown.

[0113] Thanks to this configuration, for example, a differential measurement can be applied between the two electrodes Jd and Jr in order to automatically compensate for any environmental or common-mode effects that could affect the detection performed via the electrode Jd.

[0114] Therefore, the circuit or controller MC comprises measuring means designed to calculate the difference between a representative voltage value associated with the input terminal INd and a representative voltage value detected at the input terminal INr, and its comparator means are designed to compare the difference thus generated with one or more reference thresholds (as mentioned above, the voltage value in turn represents the value of the capacitance).

[0115] The value representing the voltage obtained by the input INd can be used to determine the type of detergent. For this purpose, the controller MC is preferably programmed so that the measured value associated with the input INd (preferably compensated as described above) is compared with a plurality of predefined thresholds or values, or with values ​​corresponding to possible different detergents.

[0116] Once the measurement relative to the ambient composition has stabilized (via compensation or differential measurement of the electrode Jr), the controller MC proceeds with the process for determining the type of detergent in the container 40. As described above, this is preferably done by a method of comparison with at least one corresponding threshold. In the container there may essentially be:

[0117] -Liquid detergent ST, such as Figure 10-11 As shown;

[0118] -Detergent powder PD, such as Fig.12 As shown,

[0119] - Detergents in the form of compressed tablets ST or capsules (pods or tablets) LT, respectively Fig.13 and Fig.14 As shown,

[0120] - Air (without detergent).

[0121] By means of different equivalent permittivities given by the type of cleaning agent and its positioning within the container 40, different responses are obtained from the detection electrode Jd and thus the different types can be distinguished.

[0122] In fact, the positioning of the cleaning agent also helps to diversify the measurements, because e.g. Figure 8-9 As explained, the fluid detergent LD and the powder detergent PD will conform to the geometry of the container 40, whereas the detergent in tablet form ST or LT will maintain its own geometry and will therefore not conform to the internal contour of the container, thereby maintaining the presence of air between the measuring electrodes and the detergent, wherein the presence of this air also acts as a dielectric, further reducing the measured value.

[0123] For this purpose, in a particularly advantageous solution, suitable spacing means, such as those previously exemplified with 41, may be provided inside the container 40, so as to keep the detergent tablet ST or LT at a certain distance relative to the container wall (here the wall 40b) to which the sensor device 50 is associated, thereby further increasing the measurement difference between the tablet and the washing powder or liquid. It will be understood that, due to the presence of the aforementioned spacing means, even in the case of detergent tablets formed by pressing the same material as the washing powder, it is possible to distinguish between the two forms of detergent (the detergent in the tablet will be detected with a significantly lower signal than the detergent powder due to the greater distance between the detergent and the sensor device 50, i.e. the presence of a greater dielectric represented by the air between the tablet and the inside of the wall 40b).

[0124] The representative values ​​read via the detection electrodes Jd are digitized by the controller MC and presented as pure numerical values ​​after the quantization process; said signals are referred to here as "raw data". Therefore, each type of cleaning agent will give a different value of the raw data read by the circuit or controller MC.

[0125] Examples of three illustrative detergents are provided below. Let us assume that the geometry of the electrode Jd is optimized to provide maximum measurement at the lowest level of liquid detergent typically recommended for washing (typically 25 ml) or at the lower region of the insert wall 40b.

[0126] Liquid detergent LD : Being a liquid, this type of cleaning agent has a high dielectric constant and will fill a corresponding part of the volume of the container 40, ie there is no air between the cleaning agent and the wall 40b: This allows to have very high measurement values, for example equal to 10,000 raw data.

[0127] Powder detergent PD : In powder form, this cleaning agent has a medium dielectric constant, in any case lower than that of the liquid cleaning agent LD, and will fill a corresponding part of the volume of the container 40, with essentially no air between the cleaning agent and the wall 40b: this allows to have medium measurement values, for example raw data of 4,000.

[0128] Cleansing agent in tablets ST or LT : Being in tablet form, this cleaning agent has a low dielectric constant and does not completely fill the corresponding part of the volume of the container 40, wherein there is air between the cleaning agent itself and the wall 40b (as mentioned above, this effect can be ensured by the presence of the above-mentioned spacer 41): this leads to low measured values, such as 1,000 raw data.

[0129] In contrast, in the absence of any cleaning agent, the container would contain air, wherein the reference raw data is equal to zero, for example.

[0130] Once the nominal value for each detergent has been defined in this way, the corresponding threshold value is stored in the controller MC in order to obtain a univocal response and thus be able to identify the type of detergent currently present in the container 40. Thus, for example, if raw data between 9,000 and 11,000 are obtained after detection by the electrode Jr, it can be inferred that the detergent is in liquid form; for example, if the raw data are between 3,000 and 5,000, it can be inferred that the detergent is in powder form; for example, if the raw data are between 10 and 2,000, it can be inferred that the detergent is in tablet form.

[0131] In practice, the measurement cycle within the controller MC can perform the following comparisons:

[0132] - if the value of the raw data is below a first threshold (e.g. equal to 10), an "air" state is assigned, or the absence of cleaning agent;

[0133] - if the value of the raw data is between a first threshold value and a second threshold value (e.g. equal to 2,000), the state "tablet cleanser" is assigned;

[0134] - if the value of the raw data is between the second threshold and the third threshold (e.g. equal to 5,000), the state "washing powder" is assigned;

[0135] If the value of the raw data is above a third threshold value, the state "liquid detergent" is assigned.

[0136] In order to improve the measurement, an auxiliary control electrode Jn may be provided, preferably at least partially placed near and / or around the electrode Jd, as previously described. Figure 6-7 The electrode Jn is closer to the electrode Jd than the electrode Jr.

[0137] Fig.15 and Fig.16 Possible operating modes of the auxiliary control electrode Jn described above, or at least one operating phase of the device 50 involving the use of such an electrode Jn, are illustrated; other operating modes or other phases of such operation may include at least one of the following:

[0138] - Connection of auxiliary control electrode Jn to positive potential;

[0139] - Capacitance measurement using auxiliary control electrode Jn;

[0140] The capacitance measurement of the auxiliary control electrode Jn is carried out simultaneously or in parallel with the measurement by means of the measuring electrode Jd.

[0141] Fig.15 The case of the container 40 is schematically illustrated, for example, where a few drops of water WD remain in the container 40 at the end of the previous wash, which may affect detection in the next wash cycle if not dried (the capacitive electrodes are inherently sensitive to water due to its high dielectric constant).

[0142] In this example, the electrode Jn may be connected to a low potential (eg ground) via a corresponding terminal of the controller MC to which the corresponding drive circuit Dr is connected.

[0143] In the absence of a measurement of the auxiliary control electrode Jn, or in the case where such an electrode Jn is not driven (e.g. Fig.15 As shown), the field lines FL associated with the detection electrode Jd will not be controlled and can be affected by the droplets WD, which may distort the measurement.

[0144] In contrast, in the presence of an auxiliary control electrode Jn which is appropriately controlled by the controller MC, for example connected to ground (e.g. as shown in FIG. Fig.16 As shown), the distribution of the electric field lines FL associated with the detection electrode Jd is improved, these lines are forced to close around the same electrode Jd, that is, on the auxiliary control electrode Jn, as shown Fig.16 In other words, by appropriate control of the electrodes Jn, it becomes possible to optimize the detection area, for example by limiting it to the area of ​​actual interest, eliminating or reducing detection errors due to the possible presence of water residues WD remaining in the container 40 after the washing cycle.

[0145] In various embodiments, the electrode Jn may be driven by the circuit Dr with a predefined voltage defined by the firmware. For example:

[0146] - If the circuit Dr drives the electrode Jd at 0V (ground), the electric field strength is reduced to a minimum, e.g. Fig.16 As shown, the field lines LF are oriented in such a way that their paths are as short as possible;

[0147] - On the contrary, if the circuit Dr drives the electrode Jd with the maximum available voltage (for example equal to the power supply of the controller MC, assumed here to be 5V), the electric field strength is maximum, so that the field lines FL are oriented in such a way that their path is as long as possible, but always closed between electrodes Jd and Jn.

[0148] Therefore, in this example, the voltage-driven auxiliary control electrode Jn does not perform the measurement, but constitutes an element forcing the electric field lines FL to close with variable strength. It is therefore understood that this auxiliary electrode Jn does not replace the virtual armature obtained by the detergent, but rather acts as an auxiliary part that can be connected to the detection electrode Jd to change its shape and measurement characteristics.

[0149] The presence of the auxiliary control electrode Jn allows managing the dynamics via software by maximizing the signal of the detection electrode Jd so that the field lines FL only pass through the material to be measured in the vicinity of the same electrode Jd. Fig.16 As can be seen in the example in , the presence of auxiliary control electrodes Jn guides the field lines FL and orients them so that their path is as short as possible, but they pass through the medium of interest to be measured (i.e. the detergent). This improves the measurement efficiency by optimizing the percentage of field lines that actually pass inside the medium of interest, compared to the percentage that pass through materials that are not of interest for measurement.

[0150] As mentioned above, the operating principle of the sensor device 50 depends to a certain extent on the ambient temperature when considered in an absolute manner. Since the temperature effect is represented by a shift in the measurement associated with the electrode Jd, and if the detection quality is to be further improved, any thermal drift resulting from possible temperature changes can also be compensated with the aid of a temperature sensor, according to techniques known per se, e.g. Figure 6 and Figure 7 The type shown in TS.

[0151] From the description given, the characteristics of the invention and its advantages are clear.

[0152] The described dispenser with the corresponding sensor device has a simple, economical and compact construction, is reliable even in the long term and allows accurate recognition of the presence and type of detergent.

[0153] It is obvious that a person skilled in the art may make several modifications to the dispenser described by way of example without departing from the scope of the invention as defined in the following claims.

[0154] The electronic circuit of the sensor 50 is preferably initially calibrated or configured based on the type and / or conductivity of the detergent being detected, in particular considering that in the case of detergents with a low conductivity or resistance, a resistance may appear that is almost in series with the measuring capacitor, which resistance may lead to an increase in the time required to reach the final threshold (increased charging time of the "virtual capacitor" to which the electrode Jd belongs and / or an increase in the charging time of the capacitor C HOLD the discharge time increases); taking this into account, an initial configuration can be envisaged, for example, to take into account possible delays in sampling measurements and to avoid incorrect measurements based on values ​​that are not yet well stabilized.

[0155] The electronics of the sensor device 50 may be initialized and / or calibrated during production, wherein corresponding software or programs and / or at least some variables (such as one or more thresholds for detecting the presence and / or type of detergent) are stored. The calibration phase may include reading the electrodes Jr, for example defining the elimination of initial offsets, or compensating for parasitic capacitances due to the material, structure, thickness, etc. of the sensor and / or its mounting system.

[0156] In order to improve the detection accuracy and / or dynamics, the sensor device 50 may be equipped with a plurality of sensitive parts, each of which includes a single detection electrode Jd and / or a plurality of reference electrodes Jr.

Claims

1. A detergent dispenser for a dishwasher, comprising a dispenser body (20) and a door (30), in, The dispenser body (20) has a front portion in which a container (40) for containing detergent (ST, LT, LD, PD) is defined, the container (40) being delimited by a plurality of walls (40a-40d), wherein the door (30) is movably mounted on the dispenser body (20) so as to be movable between a closed position and an open position of the container (40), The dispenser (1) comprises a sensor device (50) having at least one sensitive portion configured to detect capacitance, The at least one sensitive portion comprises at least one single detection electrode (Jd), and the at least one single detection electrode (Jd) is arranged outside the container (40) in an adjacent or side-by-side position relative to a first wall (40b) of a plurality of walls (40b-40d) defining the container (40), And wherein the sensor device (50) comprises a control circuit (MC), the single detection electrode (Jd) is connected to the control circuit (MC) in a signal communication manner, and the control circuit (MC) is configured to detect the presence and / or type of detergent that may be present in the container (40) based on a first value representing the capacitance between the single detection electrode (Jb) and the detergent that may be present in the container (40).

2. The dispenser according to claim 1, in, The sensor device (50) comprises at least one compensation means (Jr; TS) for compensating the first value representative of the capacitance.

3. The dispenser according to claim 2, in, The compensation device (Jr; TS) comprises at least one reference electrode (Jr), which is arranged in a non-adjacent or non-juxtaposed position relative to the walls (40a-40d) defining the container (40) and is connected to the control circuit (MC) in a signal communication manner.

4. The dispenser according to claim 3, in, The control circuit (MC) is configured to compensate the first value representing the capacitance based on at least one other value representing the capacitance obtained via the at least one reference electrode (Jr), and the control circuit (MC) is particularly configured to perform a correlation and / or difference measurement between the first value representing the capacitance and the other value representing the capacitance.

5. The dispenser according to any one of claims 2 to 4, in, The compensation device (Jr; TS) comprises a temperature sensor (TS).

6. The dispenser according to any one of claims 1 to 5, in, The control circuit (MC) is configured to compare the first value representing the electrical capacitance or the first compensation value representing the electrical capacitance with at least one corresponding reference threshold value in order to infer the presence and / or type of detergent possibly contained in the container (40), wherein preferably: The control circuit (MC) is configured to compare the first value representing the capacitance or the first compensation value representing the capacitance with a plurality of reference thresholds to infer the type of detergent that may be contained in the container (40), the type of detergent being between liquid detergent (LD), powder detergent (PD), and detergent in tablet or capsule form (ST, LT).

7. The dispenser according to any one of claims 1 to 6, in, On the inner side of the first wall (40b), at least one spacing element (41) is arranged, the at least one spacing element being suitable for holding the detergent in the form of tablets (ST, LT) in a position spaced apart from the inner side of the first wall (40b).

8. The dispenser according to claim 1, in, The single detection electrode (Jd) and the control circuit (MC) are located on the same circuit support (51) mounted on the dispenser body (20), wherein preferably, at least one compensation device (Jr; TS) is also mounted on the same circuit support for compensating the first value representing the capacitance.

9. The dispenser according to claim 1 or claim 3, in: the control circuit (MC) having at least one signal input (INd, INr), to which the single detection electrode (Jd) or the at least one reference electrode (Jr) is connected, respectively, and the at least one signal input (INd, INr) is also connected or can be connected to a controllable switch (SS) and a capacitor (C HOLD ) circuit, the controllable switch (SS) can be switched between a first position and a second position, in the first position, the capacitor (C HOLD ) is connected to a voltage source (V DD ), in the second position, the capacitor (C HOLD ) is connected to the at least one signal input terminal (INd, INr), and - the control circuit (MC) is configured to switch the controllable switch (SS) from the first position to the second position so that the capacitor (C HOLD ) is discharged in a manner proportional to said first value representing the capacitance or said other value representing the capacitance, said first value and said other value being respectively associated with said at least one signal input terminal (Ind, INr).

10. The dispenser according to any one of claims 1 to 9, in, The single detection electrode (Jd) has an area that affects only the lower or middle portion of the container (40).

11. The dispenser according to any one of claims 1 to 10, in, The sensor device (50) further comprises an auxiliary control electrode (Jn), which is located close to the single detection electrode (Jd) and can be controlled by the control circuit (MC) so as to improve the detection operated by the single detection electrode (Jb), preferably so as to avoid or reduce abnormal measurements caused by the possible presence of water residues in the container (40).

12. A dishwasher comprising a detergent dispenser according to one or more of claims 1-11.

13. A method for detecting the presence and / or type of detergent in a container (40) of a detergent dispenser (1) for a dishwasher, The following steps are involved: - providing at least one single detection electrode (Jd) which is located outside the container (40) in an adjacent or side-by-side position relative to one wall (40b) of the plurality of walls (40b-40d) delimiting the container (40), - detecting the presence and / or type of detergent possibly present in said container (40) based on a value representative of the electrical capacitance between said single detection electrode (Jd) and the detergent possibly present in said container (40).

14. A sensor device for detecting the presence and / or type of detergent possibly contained in a container (40) of a detergent dispenser (1) for a dishwasher, the sensor device (50) having at least one sensitive portion configured for detecting electrical capacitance, in, The at least one sensitive portion comprises at least one single detection electrode (Jd), which is pre-arranged to be mounted outside the container (40) in an adjacent or side-by-side position relative to a first wall (40b) of a plurality of walls (40b-40d) defining the container (40), And wherein the sensor device (50) comprises a control circuit (MC), the at least one single detection electrode (Jd) is connectable to the control circuit (MC) in a signal communication manner, and the control circuit (MC) is configured to detect the presence and / or type of detergent that may be present in the container (40) based on a first value representing the capacitance between the single detection electrode and the detergent that may be present in the container (40).

15. A sensor device for detecting the presence and / or type of detergent possibly contained in a container (40) of a detergent dispenser (1) for a dishwasher, the sensor device (50) having at least one sensitive portion configured for detecting capacitance and comprising at least one detection electrode (Jd), in, The sensor device (50) comprises a circuit support (51), on which is arranged: - said detection electrode (Jd), - Reference electrode (Jr), an auxiliary control electrode (Jn) arranged close to the detection electrode (Jd), preferably in such a way as to surround at least a part of the detection electrode (Jd), a control circuit (MC), to which the detection electrode (Jd), the reference electrode (Jr) and the auxiliary control electrode (Jn) are connectable in signal communication, wherein the circuit support (51) is pre-arranged to be mounted outside the container (40), wherein the detection electrode (Jd) is in an adjacent or parallel position relative to a first wall (40b) of a plurality of walls (40b-40d) defining the container (40), and the reference electrode (Jr) is in a non-adjacent or non-parallel position relative to a wall of the plurality of walls (40a-40d) defining the container (40), The control circuit (MC) is configured to detect the presence and / or type of detergent that may be present in the container (40) based on a first value representing the capacitance, which is obtained with the help of the at least one detection electrode (Jd) and the auxiliary control electrode (Jn), and is compensated based on a second value representing the capacitance obtained via the reference electrode (Jr).

16. A detergent dispenser (1) for a dishwasher, comprising a sensor device (50) according to claim 14 or 15.

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