System for detecting one or more physical properties of the service water of a household appliance

Abstract

The object of the present invention is an electronic immersion device (1) for metering at least one physical quantity of a fluid, preferably service water circulating inside a household appliance and / or contained inside a tank or storage thereof, said at least one physical quantity being at least the electrical conductivity of said service water. Said metering device (1) further comprises a galvanic isolation system (31).

Description

[0001] SYSTEM FOR DETECTING ONE OR MORE PHYSICAL PROPERTIES

[0002] OF THE SERVICE WATER OF A HOUSEHOLD APPLIANCE

[0003] DESCRIPTION

[0004] The object of this invention is a device adapted to detect at least one physical quantity of a fluid, preferably water.

[0005] More precisely, the object of this invention is an electronic immersion device for detecting the electrical conductivity of a fluid, preferably water, contained inside a tank or storage of a household appliance or circulating inside a pipe thereof.

[0006] Even more precisely, the object of this invention is an electronic immersion device for detecting the electrical conductivity' of a fluid, preferably water, capable of implementing additional or accessory' functions, e.g. for controlling and managing the temperatures of the fluid and / or for sanitising it.

[0007] The invention mainly falls within the sector of the production of household appliances, more precisely in the field of the realisation of the laundry' washing machines, washer-dryers and / or dishwashers that may be used both within the domestic and industrial scope.

[0008] Of course, nothing prevents the possibility of extending the use of the aforementioned electronic immersion device also to other sectors, e.g., in that of the electric storage or heat pump water heaters, tanks for storing water for food and / or sanitary use or in all those water storages (or similar fluids), whether temporary' or not, where there is a need to check and / or manage the chemical - physical properties of said fluid and / or the usage and withdrawal characteristics thereof.

[0009] It is known that all the aforementioned household appliances, although differing from each other in terms of construction and functional characteristics, are associated with the presence of at least one water storage and the presence of a plurality of devices that control the heating, withdrawal and / or quality thereof.

[0010] For example, it is known the use of one or more electrical resistances that allow an appropriate heating and / or thermostating of the storage water up to a temperature sufficient to meet the service that the household appliance must provide (e.g., withdrawal for sanitary or food use and / or suitable for washing laundry or dishes) and / or the installation of ultraviolet sanitisation devices, able to reduce or eliminate the viral and / or bacterial load and / or other pathogenic microorganisms that may be present in the water.

[0011] It is also known the presence of sensors designed to detect the chemical-physical or operational characteristics of said water, so as to manage the operation of the household appliance and / or monitor any anomalies thereof.

[0012] For example, reference is made to the known temperature sensors or probes able to detect the temperature of the water contained in the storage of said household appliances and, consequently, to “drive”, by activating or deactivating them, said one or more electrical resistances, and / or to the sensors capable of detecting the turbidity of the water, and / or electrical conductivity thereof and / or other parameters.

[0013] The electrical conductivity is the ability of a material or liquid, such as water for example, to conduct electrical current and it is a parameter that indicates the content of salts dissolved in it.

[0014] This means that the more salts are dissolved, the more water shall be able to pass the current, while substantially “pure” water would be a “poor” conductor of electricity.

[0015] In general, it is also possible, by determining the electrical conductivity of water, to identify and establish the hardness thereof or other parameters / characteristics. A high electrical conductivity value may indicate a high hardness and a consequent high probability that corrosive and / or encrusting phenomena will occur inside the household appliance, for example the formation of indissoluble deposits, commonly known as “scale”, in some of its components.

[0016] It is clear that the electrical conductivity of water therefore represents an important parameter to detect and monitor in order to guarantee the health of household appliances.

[0017] By way of an example, with reference to the washing machine sector, all said devices and / or sensors are generally mounted in the washing water supply pipes and / or inside the drum and / or on the inner wads of the relative washing tanks.

[0018] However, such technical and construction choices have not proven to be free from drawbacks.

[0019] The presence of said devices and / or sensors requires, for example, the creation of specific installation seats and / or housings, this causing a significant increase in the production times and costs of the household appliance and / or changes or adaptations of the related production processes.

[0020] Furthermore, the greater the number of said components, the greater the number of seats and / or housings for their installation; therefore, the higher the risk of water leaks and leakages therethrough, especially in presence of defective or worn couplings and / or seals during the operating life of the household appliance. Similarly, the greater the number of components to be installed, the higher the risk of breakages or malfunctions of the same and therefore of the household appliance.

[0021] All of this may inevitably translate into an unwanted increase in maintenance costs.

[0022] It is also known that the aforementioned devices, being electrically powered, must meet certain safety requirements, especially when operating in contact with water and / or accessible and potentially reachable by a user.

[0023] The current safety' and isolation systems, for example comprising transformers or similar magnetic devices, are complex, expensive and bulky.

[0024] The need to isolate said devices is particularly felt in all those household appliances that, provide for storages, tanks, reservoirs (such as, for example, in the field of washing machines), or other components, grounded. In such case, even the reliability of the measurements carried out by said devices may be unsatisfactory' for the intended objectives.

[0025] The object of the present invention is to eliminate the drawbacks of the prior art, listed above, by providing an electronic immersion device for metering at least one physical quantity of a fluid, preferably water, contained inside a reservoir or storage or circulating inside a pipe of a household appliance, which provides for a reliable, safe and harmless isolation system for the user.

[0026] A further object of the present invention is to integrate in a single electronic immersion device a plurality of sensors for the detection and metering of different physical quantities of a fluid, preferably water, contained within a reservoir or storage or circulating within a pipe of a household appliance.

[0027] A further object of the present invention is to implement the metering of at least one physical quantity of a fluid, preferably water, contained or circulating within a household appliance in the same metering electronic device, and a sanitisation function of said fluid.

[0028] A further object of the present invention is to integrate an electronic immersion device for the metering of at least one physical quantity of a fluid, preferably water, contained or circulating within a household appliance in a component already provided therein, in particular in a component for heating and / or thermostating said fluid.

[0029] A further object of the present invention is to provide for an electronic immersion device for metering at least one physical quantity of a fluid, preferably water, contained or circulating inside a household appliance, which is efficient, safe, economical and reliable and without this involving substantial modifications to the structure and / or basic components of said household appliance.

[0030] A further object of the present invention is to provide for an electronic immersion device for metering at least one physical quantity of a fluid, preferably water, contained or circulating inside a household appliance that allows retrofitting and / or upgrading operations of household appliances already produced and on the market.

[0031] These and other objects are achieved in accordance with the invention, with the features listed in the annexed independent claim 1.

[0032] Further features of the present invention shall be better highlighted by the following description of one or more preferred embodiments, in accordance with the patent claims and illustrated, purely by way of a non-limiting example, in the annexed drawing tables, wherein:

[0033] - Figure 1 schematically shows the electronic immersion metering device according to the invention;

[0034] - Figure 2 schematically shows a possible installation and application form of the electronic metering device of figure 1;

[0035] - Figure 3 schematically show's a section view of the electronic metering device of figure 1;

[0036] - Figure 4 shows an electrical / electronic diagram of a component of the electronic metering device of figure 1 ;

[0037] - Figure 5 schematically shows a possible form of installation and application of the electronic metering device according to a second embodiment of the invention;

[0038] --- Figure 6 schematically shows a possible form of installation and application of the electronic metering device according with a third embodiment of the invention.

[0039] The elements of the electronic device 1 for metering at least one physical quantity of a fluid, preferably water, circulating and / or contained inside a household appliance are now described using the references described in the figures 1 to 6. With the purpose of highlighting some features instead of others, not necessarily what described in the figures is to scale.

[0040] It is also noted that any dimensional and spatial term (such as “lower”, “upper”, “inner”, “outer”, and the like) refers to the positions of the elements as shown in the attached figures, without any limiting intent relative to the possible operating conditions. In the present description, at least initially, reference shall be made to an electronic immersion device I for metering at least one physical quantity of a fluid, preferably water, contained within a generic reservoir or storage provided in a household appliance (not shown) and used for different purposes, e.g., such as washing water, rinsing water, sanitary water or the like.

[0041] Naturally, nothing prevents the installation thereof, with small adaptations within the reach of a man skilled in the art, even on pipes and ducts inside the household appliance, normally arranged for the supply, delivery and / or discharge of said water.

[0042] Hereinafter, “storage” is generically to be understood as any reservoir, vessel or container, in the most varied shapes, geometries and volumes, able to store a certain amount of water.

[0043] For simplicity, regardless of the type of household appliance and the function thereof, said water shall be indicated with the expression “sendee water”, while the electronic immersion device 1 for metering at least one physical quantity of a fluid shall be briefly abbreviated to “metering device 1”.

[0044] According to a possible embodiment of the invention, which is among the preferred ones, said metering device 1 may be integrated in household appliances that provide for heating the water contained in the storage thereof, such as, without any limiting intent, laundry’ washing machines, washer dryers, dishwashers and / or in a storage and / or heat pump w'ater heater, solar storages or, more generally, in any other reservoir or vessel subject to the control and / or regulation and / or thermostating of the service water.

[0045] Preferably, said metering device I may be installed in the proximity of a component, already equipped with said household appliance, normally designed for heating the service water or, as shall be seen in more detail, be advantageously integrated with it.

[0046] The metering device 1 of the invention may therefore be positioned on an inner wall of the storage, in the proximity of at least one electrical resistance 2 thereof designed to control and thermostat the sendee water or, as preferred, directly integrated with the same electrical resistance 2.

[0047] Said metering device 1 may consist of a device capable of metering and detecting the electrical conductivity of the sendee water, e.g. a conductivity meter 1.

[0048] As shown in the accompanying figures, said conductivity meter 1 comprises and cooperates with at least two probes 12 that may act as metal electrodes 12 for metering the electrical conductivity of the service water.

[0049] Said electrodes 12 are normally placed at a suitable distance D from each other (e.g., in the order of cm) and capable of being in direct contact with the sendee water when said conductivity meter 1 is installed in the household appliance and operational.

[0050] A known voltage i s applied between said electrodes 12 which generates an electric current that flow's between them, crossing the service water wherein they are immersed.

[0051] The methods of metering and acquiring the electrical conductivity of the service water shall be discussed in detail during the present description. In such context it is therefore sufficient to specify that one of said electrodes 12 is called and behaves as an emitter electrode 12. a, the other as a receiver electrode 12. b and that the conductivity meter 1 comprises and cooperates with a control board 3 which is equipped with components and related connections for the correct operation and management thereof.

[0052] As shown in figure 1 and / or 3 and / or 5 and / or 6, said conductivity meter 1 may comprise a hollow7tubular body or casing 10 (hereinafter referred to as “casing 10”), preferably made of glass, closed at the tip by a cap 11, preferably made of insulating material, e.g. insulating resin.

[0053] At least one of said electrodes 12. a, 12. b may be housed on said cap 11, so as to be protruding and projecting externally from the casing 10 of the conductivity meter I .

[0054] More precisely, according to the executive embodiments shown respectively in figure 3 and 6, both electrodes 12. a and 12.b of the conductivity meter 1 are mounted on the cap 1 1 thereof' while figure 5 shows an alternative embodiment that provides for only one electrode 12. a, 12. b, preferably the emitter electrode 12. a, to be installed protruding from said cap 11; such embodiments and the peculiarities thereof shall be discussed in detail during the present description.

[0055] For example, with reference to the embodiment of figure 5, it may already be specified that the second electrode 12. b, which acts as a receiver electrode 12.b, may consist of a metal component of the household appliance whereon the same conductivity meter 1 is installed, provided that it is necessarily grounded.

[0056] For example, said second electrode 12.b may consist of a portion 210 of an electrical resistance 2, preferably in a branch or coil 210 thereof, wherein, as shall be seen, the conductivity meter 1 of the invention may be installed.

[0057] As shown in figure 5, said branch 210 of the electrical resistance 2 may consist of the branch immediately facing and closer to the emitter electrode 12. a installed on the cap 1 1 of the conductivity meter 1.

[0058] Therefore, according to the embodiment of figure 5, the metering area of the electrical conductivity is that comprised between the emitter electrode 12, a and the facing branch 210 of the electrical resistance 2, connected to the ground, such configuration ensures a marginal and / or negligible contribution of the other grounded elements of the household appliance further from the same emitter electrode 12. a, in the metering of the electrical conductivity.

[0059] For the embodiments of figure 3-4 and 6, the metering area of the electrical conductivity of the service water is instead, as already partially anticipated, the space between the two electrodes 12. a, 12. b mounted protruding from the cap 1 1 of the conductivity meter 1, also in this case with a negligible influence of the external elements, in the detection of said electrical conductivity.

[0060] A cable 13, preferably bipolar and double insulated, passing at least partly inside the casing 10 of the conductivity meter 1, enables to electrically power, at least one, or both, said electrodes 12. a, 12. b, and, at the same time, to transmit the conductivity metering earned out to said control board 3, and from this to a second electronic board, which is normally that of the household appliance. From now on, for descriptive simplicity, said control board 3 shall be referred to as “interface board 3”, the cable 13 shall be referred to as “bipolar cable 13” while the electronics or board of the household appliance (not shown) shall also be referred to as “main control unit”.

[0061] The welding between the bipolar cable 13 and the one or more metal electrodes 12. a, 12. b of the conductivity meter I to be electrically powered is completely insulated by the aforementioned resin cap 11, where their mutual connection and coupling is made.

[0062] According to the invention, the dimensions of the conductivity meter 1 and a specific positioning therewithin of the bipolar cable 13, e.g. in a distal position with respect to the X-X axis of the casing 10 of said conductivity meter 1, or in substantial proximity to the inner wall 100 thereof, allow to define a sufficiently large cavity 14 for the possible insertion and housing of a printed circuit 15.

[0063] On said printed circuit 15, according to the invention, it is possible to install and fix in a known manner:

[0064] -- additional metering devices 4 of a further physical quantity of the sendee water, hereinafter referred to as “suppl emen tary” with respect to those for the detection of conductivity (conductivity meter 1), and / or

[0065] - any devices 5 adapted to implement specific additional functions, hereinafter referred to as “accessory devices 5”.

[0066] The additional devices and / or accessories 4, 5, installed on the printed circuit 15, are isolated:

[0067] - from the sendee water by means of the glass casing 10 of the conductivity meter 1, and

[0068] - from the one or more electrodes 12. a, 12. b thanks to the cap 11 in resin (or similar / equivalent plastic material) and / or because they are appropriately installed at a minimum safety distance from said one or more electrodes 12. a, 12. b (e.g., comprised between 1 and 4 mm, preferably at least approximately 2 mm) and / or due to the choice and the presence of the double-insulated bipolar cable 13. Without any limiting intent, said additional metering devices 4 may comprise at least one temperature sensor 40 for the service water, for example a thermistor of the NTC {Negative Temperature Coefficient) or PTC {Positive Temperature Coefficient) type, the detection of the water temperature being always guaranteed despite the presence of the casing 10 of the conductivity meter I, for this purpose being preferably made of high thermal conductivity quartz glass.

[0069] The aforementioned accessory devices 5 may instead implement hygienisation and sanitisation functions of the sendee water and therefore consist of at least one sanitising device 5 for the elimination, or at least a significant reduction, of bacteria, viruses and / or other pathogenic microorganisms possibly present in said service water.

[0070] Without any limiting intent, as shown in figure 3, said sanitising device 5 may preferably consist of an ultraviolet emitter 50 comprising one or more UV (ultraviolet) lamps or LEDs.

[0071] For all the reasons mentioned above, the casing 10 of the conductivity7meter 1 is preferably made, at least in part, of quartz glass, said material in fact:

[0072] --- being particularly transparent to the ultraviolet radiation, thus allowing the radiation of the ultraviolet emitter 50 of the sanitising device 5 to pass effectively therethrough,

[0073] - having physical characteristics suitable and compatible with the use and operation of the aforementioned at least one temperature sensor 40 for detecting the temperature of the service water of a household appliance and / or for the safe activation / deactivation of the same sanitising device 5, 50.

[0074] A quartz glass is in fact characterised, as anticipated, by a high thermal conductivity and at the same time by a high electrical resistivity.

[0075] In practice, the quartz casing 10 of the conductivity meter 1 of the invention, besides preventing the direct contact between service water and said ultraviolet emitter 50 and temperature sensor 40, is able to electrically isolate them from the support whereon it is mounted, for example, from the flange 20 of an electrical resistance 2; such preferred installation embodiment of the conductivity meter 1 of the invention shall be discussed shortly.

[0076] The quartz glass also ensures greater precision and reactivity in reading the temperatures of the service water of the storage of the household appliance.

[0077] In short, based on what has been said so far, the metering device 1 of the invention may comprise a conductivity meter 1, possibly equipped with at least one temperature sensor 4, 40 and / or a sanitising device 5, 50, connected to an interface board 3, in turn cooperating and communicating with an electronic control unit of the household appliance normally designed to manage and control the operation of the same household appliance, for example, to implement washing cycles and programs and / or to signal any malfunctions and / or to activate any accessory' or supplementary' functions (e.g. sanitisation).

[0078] Without any limiting intent, the interface board 3 of the conductivity meter 1 may be positioned in any useful point of the household appliance, for example, in correspondence or proximity of said main control unit or on the wiring or special housing or seat, for example obtained externally to a storage thereof for the service water.

[0079] The printed circuit 15 of the conductivity meter 1 is electrically connected to the interface board 3 via specific and known wiring 16.

[0080] At least the following components / elements are therefore provided on said interface board 3 (see figure 4, by way of a non-limiting example):

[0081] --- connectors 34 for:

[0082] - the power supply lines of the various components and devices of the interface board 3 and / or for the relative conductivity meter 1, for example the Vcc and GND lines respectively connected to the positive and negative pole (ground) of the power supply energy source,

[0083] - the communication lines with the main control unit of the household appliance, said lines therefore being able to comprise at least:

[0084] - one or more communication lines for the transmission of the temperature signal acquired by the relative sensor 40, for example, as mentioned, of the detected resistive value of the NTC thermistor representing the temperature metering of the service water,

[0085] - one or more communication lines of the conductivity value measured between the electrodes 12. a, 12.b of the conductivity meter 1, through which the activation of the sanitising device 5, 50 or of the temperature sensor 4, 40 (NTC / PTC) may also be managed;

[0086] - connectors 35 for the reciprocal connection between the interface board 3 and the printed circuit 15 comprising at least the temperature sensors 4, 40 and / or the sanitising device 5, 50, said connectors 35 being therefore intended and arranged to couple with the aforementioned wiring 16 of the printed circuit 15;

[0087] - a microprocessor 36 capable of

[0088] - receiving, managing and processing the conductivity and / or temperature signals coming respectively from the electrodes 12. a, 12,b of the conductivity meter 1 and / or from the related at least one temperature sensor 4, 40 and transmitting them to the main control unit of the household appliance, and / or

[0089] - managing autonomously, or upon command of the control unit of the household appliance, the activation / deactivation of the sanitising device 5.

[0090] The microprocessor 36 may preferably comprise:

[0091] --- at least one square wave generator 360 (which, as is known, enables to act on parameters such as the frequency, the amplitude and the possible duty' cycle of the signal received and to be processed), connected and cooperating with the emitter electrode 12. a of the conductivity meter 1, and

[0092] --- at least one rectifier and peak detector 361 (which, as is known, enables to detect and maintain peak voltage levels and to rectify a possible bipolar / bidirectional signal transforming it into a unipolar / monodirectional signal), connected and cooperating with the receiver electrode 12,b.

[0093] The aforementioned communication lines to the control unit of the household appliance for the conductivity and / or temperature meterings may transmit signals that are: - “independent”, i.e. representative and proportional to the conductivity and resistivity values detected respectively between the electrodes 12. a, 12. b of the conductivity meter 1 and by the at least one temperature sensor 4, 40, or

[0094] - “serial”, i.e. encoded and digitalised signals starting from said conductivity and resistivity meterings carried out.

[0095] It is known that the electrodes 12. a, 12. b of the conductivity meter 1 may preferably consist of terminals operating at low voltage (example of figure 4), unlike the temperature sensors 4, 40 and / or of the sanitising device 5, 50 that instead operate at high voltage.

[0096] However, nothing prevents the at least one of said electrodes 12. a, 12. b to be:

[0097] - referred / connected to the ground, as shown in figure 6; in such case, one of said electrodes 12. a, 12. b, preferably the receiver electrode 12.b, may be connected, preferably via a connection bridge 17, to the ground terminal 24 of the flange 20 of the electrical resistance 2 of the household appliance,

[0098] - replaced by the ground, as instead shown in figure 5, by means of the ground terminal 24 of the electrical resistance 2 whose branch 210, as anticipated, acts as one of the electrodes 12. a, 12.b of the conductivity meter 1, preferably as a receiver electrode 12.b.

[0099] For a correct and safe operation of the conductivity meter 1 of the invention, it is therefore necessary' that said electrodes 12. a, 12,b, or more generally any further component or element operating at low voltage, possibly present, are galvanically isolated, for example by means of a galvanic isolation system 31.

[0100] Said galvanic isolation system 31 may be appropriately arranged, according to different methods, which shall be detailed shortly, between said interface board 3 and said conductivity metering electrodes 12. a, 12. b, preferably integrated with the same interface board 3.

[0101] Without any limiting intent, said galvanic isolation system 31 may comprise one or more decoupling capacitors 31.n, for example in class Y1 (or similar / the like), cooperating and connected, in the ways that shall be described shortly, to the emitter electrode 12. a and to the receiver electrode 12,b. Without any limiting intent, therefore, a circuit 30 is provided on the interface board 3, for the galvanic isolation via said one or more decoupling capacitors

[0102] 31.n.

[0103] According to the first executive embodiment of figure 4, the galvanic isolation system 31 may comprise a pair of class Y1 capacitors 31. a, 31.b, each one placed substantially in proximity or at a respective connection point 32, 32. a,

[0104] 32. b (substantially a connector 32, 32. a, 32. b shown only schematically in figure 2) between the interface board 3 and the aforementioned bipolar cable 13 of the conductivity meter 1.

[0105] In the embodiments of figure 5 and / or 6, said galvanic isolation system 31 may instead comprise:

[0106] - a first pair of class Y1 decoupling capacitors 31.c, 31.d arranged in series with each other and with the emitter electrode 12. a, and positioned in a substantial proximity of the connection point 32. a of said emitter electrode 12. a on the interface board 3, and

[0107] --- a third decoupling capacitor 31.e in series with the receiver electrode 12. b, and adapted to ground the connection point 32. b of said receiver electrode 12. b to the interface board 3.

[0108] It is also specified that even said third capacitor 3 I .c may be a class Y1 capacitor, preferably with a value of a few tens of nanofarads, or, more generally, with a value such as to guarantee the non-dispersion to the ground provided by the standards.

[0109] According to the invention, said interface board 3 may also comprise a filtering system 33 of at least the communication lines with the main control unit, such measure being required in all those cases in which the conductivity meter 1 detects the electrical conductivity' of the service water contained in grounded storages or reservoirs (e.g., as it may happen for washing machine or washerdryer tubs or in the case of storage water heaters; such measure, on the contrary', would not be strictly necessary in case of plastic material reservoirs or storages). In fact, in case of grounded storages or reservoirs, the metering signal of the conductivity meter 1 may be strongly disturbed, compromising the reliability and quality of the detection carried out.

[0110] In fact, the electrodes 12. a, 12,b of the conductivity meter 1 are in series with the respective capacitors 31 ,n, therefore the metering signal generated and output by the electrodes of the conductivity meter 1 necessarily turns out to be of the impulsive type with harmonic components at high frequencies, the same frequencies generally present in the background noise. The noise with the high frequency components thereof may overlap with the metering signal, altering its value.

[0111] The conductivity metering may therefore be interpreted by the main control unit of the household appliance as a signal overlapped by noise, making it poorly accurate or in some cases unusable.

[0112] The filtering system 33, applied to all the connections between the interface board 3 and the control unit of the household appliance, reduces or eliminates the disturbance for metering purposes, thus allowing the noise component to be attenuated and making it irrelevant for metering purposes.

[0113] By way of a non-limiting example, said filtering system 33 may comprise high frequency inductors 330 (or, alternatively, active filters) on the connection lines with the main control unit of the household appliance.

[0114] More precisely, at least one inductor 330 may be provided for each of the aforementioned power supply lines (Vcc, GND) and / or conductivity and / or temperature signal communication and transmission to the aforementioned control unit of the household appliance.

[0115] For reasons that shall be explained shortly, the interface board 3 is completed by a cunent detector 37, also referred to as “'shunt resistor 37”, which consists of a device adapted to measure an electric current as a function of a voltage drop across a resistor 370, connected to the filtered GND

[0116] As shown for example in figure 4, 5 or 6, said shunt 37 is therefore advantageously positioned between the receiver electrode 12.b and the microprocessor 36, preferably between the capacitor 31 ,b or 31 ,e of the receiver electrode 12. b and the peak detector 361 of the microprocessor 36.

[0117] The description of an operating mode of the conductivity meter 1 of the invention may be now made in the hypothesis in which it comprises integrated, in addition to the electrodes 12. a, 12.b for measuring the electrical conductivity of the sendee water, at least one temperature sensor 4, 40 and / or a possible sanitising device 5, 50.

[0118] For the metering of conductivity, the microprocessor 36 of the interface board 3, with which the conductivity meter 1 of the invention cooperates and is connected, generates a square wave W1 through its wave generator 360.

[0119] The generated square w'ave W1 is then filtered from the decoupling capacitor 31. a (figure 4) or from the pair of decoupling capacitors 31.c, 31 ,d (figure 5 and / or 6) of the emitter electrode 12. a which, as seen, guarantee the galvanic isolation, and then introduced (see Wl.in) into the sendee water in the storage of the household appliance.

[0120] An alternating electric wave W2, ideal for the correct detection of its conductivity and capable of being intercepted by the second receiver electrode 12.b of the conductivity meter 1 wall therefore be transmitted into the service water.

[0121] The electric signal acquired by the receiver electrode 12. b, representative of the detected electric conductivity, is then sent back to the microprocessor 36, but not before being filtered by the corresponding decoupling capacitor 3 l.b (figure 4) or 31.e (figure 5 and / or 6) and being passed through the shunt resistor 37.

[0122] Said electric signal is then read in its peak value by the rectifier and peak detector 361 of the microprocessor 36 and finally processed and calibrated based on the temperature value that the service water substantially has at the time of detection and metering of the electric conductivity thereof.

[0123] It is known, in fact, that the value of the electrical conductivity of water is influenced by the temperature of the service water according to a direct proportionality.

[0124] For such temperature metering, to be correlated to the detected conductivity, a temperature probe may contribute, preferably the at least one temperature sensor 4, 40 integrated, as seen, to the conductivity meter 1 of the invention.

[0125] The microprocessor 36 of the interface board 3 is therefore appropriately arranged to activate, when necessary, said at least one temperature sensor 4, 40, said activation being able to be managed jointly with the detection of the electrical conductivity and / or at a specific time instant substantially close to said conductivity metering (e.g., just before or after said conductivity metering).

[0126] The signal representative of the electrical conductivity of the service water, compensated according to the temperature of the same, is then transmitted in absolute value to the electronics of the household appliance (e.g., as mentioned, to the main control unit thereof) through the dedicated communication line.

[0127] At this point, said value may then be interpreted as a data representative of the hardness of the service water, according to which the household appliance may set and / or regulate / modify its operation to preserve its operational longevity or that of the specific components thereof (e.g., the electrical resistance); by way of an example, the household appliance may emit or signal warning messages or promote self-protection procedures in the event that the detected conductivity value is indicative of a risk of formation of limescale or similar indissoluble deposits.

[0128] This may enable the prediction and / or advance planning of appropriate maintenance, control or replacement interventions of those components most subject to the formation of said deposits and storages.

[0129] It should also be noted that the metering of the electrical conductivity of the service water also lends itself to other objects and purposes of the invention, in addition to that of determining the hardness, as considered up to now.

[0130] The detected electrical conductivity may, for example, be advantageously correlated, through appropriate software supplied with the control unit of the household appliance, to the concentration of specific substances dissolved and / or suspended in a fluid.

[0131] For example, in the field of washing machines, the electrical conductivity measured by the conductivity meter 1 of the invention may be representative of the concentration and quantity of detergent present in the service water contained in the washing tub thereof, said data allowing to:

[0132] - optimise the washing and rinsing programs, by improving, for example, e.g. the dosing and quantity of detergent and / or detergents that may be used,

[0133] - make the energy and water consumption of the household appliance more efficient.

[0134] Furthermore, nothing prevents the detection of electrical conductivity from also being indicative of the presence or not of service water, between the electrodes 12. a and 12.b of the conductivity meter I .

[0135] It is known, in fact, how it is easy to discriminate between the presence of water between said electrodes 12. a, 12. b and its absence, in which case the measured conductivity is substantially that of the air and therefore characterised by values significantly lower than those typical of water.

[0136] By way of a non-limiting example, such information is particularly suitable for managing the switching on / off of the electrical resistance which in fact may not operate “dry”, i.e. when not adequately immersed in water, and / or for the calibration of any other sensors supplied with the household appliance, e.g. for the level sensor of the water contained in its storage or reservoir (such as, for example, the aforementioned tub of a washing machine)

[0137] According to the invention, the microprocessor 36 of the interface board 3, which, as seen, may interface with the electronics of the household appliance to exchange data and signals relating to the aforementioned meterings of conductivity and / or temperature of the sendee water, may also receive commands from the main control unit to activate the sanitising device 5, 50, obviously when present.

[0138] In other words, the activation of the sanitising device 5, 50 may be managed by input from the control unit of the household appliance.

[0139] Even the operation of the sanitising device 5, 50 may be correlated to the temperature of the service water contained inside the household appliance. Such temperature may therefore be appropriately detected and acquired, for example, by the temperature sensor 4, 40 of the conductivity meter 1 (or by any additional temperature sensors or probes with which the household appliance may be equipped).

[0140] For example, the sanitising device 5, 50 of the conductivity meter 1 is normally kept switched off (or is deactivated) if the temperature of the service water detected by the temperature sensor 4, 40 is higher than a threshold value (for example, equal to 60°C) which ensures a very low or negligible risk of development and proliferation of bacteria, viruses or pathogenic microorganisms (at such temperature, in fact, the sanitisation occurs spontaneously without any need for the intervention of sanitising devices).

[0141] Furthermore, high water temperature values, read by the at least one temperature sensor 4, 40, around the sanitising device 5, 50, may be considered as representative of malfunctions, breakdowns and / or excessive overheating of the emitter or ultraviolet LED 50 thereof, which shall be, for safety reasons, switched off and unpowered (said identification of any breakdowns and malfunctions of the ultraviolet emitter or LED 50 may however require the implementation of specific safety logics and algorithms in the electronics of the household appliance).

[0142] Finally, it should be noted that the at least one temperature sensor 4, 40 integrated in the conductivity meter 1 of the invention, in addition to being used, as just seen, for measuring the temperature of the service water to be correlated with the detection of the conductivity thereof and / or for the activation / deactivation of the sanitisation device 5, 50, may also be used for the typical heating and / or thermostating operations of the service water, i.e. for the activation and deactivation of an electrical resistance 2 of a household appliance (exactly as with the traditional and known state-of-the-art probes used up to now).

[0143] In accordance with a preferred embodiment of the invention, as already partially anticipated, the conductivity meter 1, described above, may be installed and integrated on said electrical resistance 2 of the household appliance used for heating and / or thermostating the service water contained in a storage thereof (e.g. the tub of a washing machine or a reservoir of a storage water heater).

[0144] According to such applicative embodiment, on the flange 20 of said electrical resistance 2 a seat 23 is therefore appropriately obtained for the installation of the conductivity meter 1 according the multiple executive and functional embodiments thereof, described above.

[0145] Preferably, said seat 23 may comprise a through hole or slot that extends for the entire thickness of the flange 20, between its face 200 that houses the electrical power connectors (not shown) and that 201 supporting the heating element 21 which is shown in the attached figures (see in particular figure 2) without any limiting intent, as a coil (obviously nothing prevents other similar types of heating elements among those known and available on the market).

[0146] Once inserted into said seat 23, the conductivity meter 1 of the invention will be projecting from said face 201 of the flange 20 of the electrical resistance 2 and therefore protruding inwards of the storage of the household appliance, so as to be, when provided, in contact with the service water.

[0147] Such application also allows the use of the gasket (not shown), generally made of robber, of the flange 20 of the electrical resistance 2 to guarantee the correct water tightness of the seat 23; in such case, therefore, there is no need for additional gaskets specifically designed for the conductivity meter 1, with advantages both in terms of cost and maintenance and simplicity' of the production and assembly processes.

[0148] According to this executive embodiment of the invention, the electrical resistance 2 is therefore able to combine its typical function of heating the service water of a storage (or equivalently along a pipe thereof) with that of detecting the electrical conductivity and, when provided, measuring the temperature of said water and / or sanitising it from bacteria, viruses and / or other path ogen i c m icroorgani sm s .

[0149] Such constructive choice may also facilitate retrofitting and upgrading operations on household appliances already on the market and / or used which consist of the simple replacement of the traditional electrical resistances with those comprising the conductivity meter 1 of the invention, without this requiring a redesign of the household appliance and / or structural modifications to the relative storage (or other parts) and to the mechanics thereof

[0150] This in fact avoids the need to provide additional housings or seats on the storage, directly dedicated to the installation of each of such functional components (e.g., conductivity meter 1, temperature sensor 4, sanitising device 5), all of which being now advantageously integrated into a single device consisting, for example, in the electrical heating resistance of the same storage.

[0151] It is clear that with the conductivity meter 1 of the invention, and the relative operation and installation method thereof in a household appliance, the stated objects are achieved; in particular, the possibility of implementing in a single electronic immersion device for detecting the electrical conductivity of the service water, contained inside a tank or accumulator or circulating inside a household appliance, a plurality of accessory or supplementary functions such as, without any limiting intent, that of sanitising said service water and / or measuring the temperature thereof.

[0152] As seen, the installation and use of the conductivity meter 1 of the invention is also reliable, safe and free from danger for the user:

[0153] --- its interface board 3 being galvanically isolated (e.g. by means of class Y1 decoupling capacitors 31 ,n) from the service water, and

[0154] --- the components operating at high voltage, integrated on it, in particular the at least one temperature sensor 4, 40 and / or the sanitising device 5, 50, being isolated:

[0155] - from water, by means of the glass casing 10 of the same conductivity meter 1,

[0156] - from the electrodes 12 of said conductivity meter 1, by installing them at a minimum safety distance therefrom (e.g., at least 2 mm) and providing for the cap 11 in insulating resin and the double-insulated bipolar cable 13. The installation and integration of the conductivity meter I of the invention in the flange 20 of an electrical resistance 2 for the heating of the sendee water of a household appliance, i.e. on a component, already supplied, allows for an efficient, economical and reliable use thereof, without implying substantial modifications to the structure and / or basic components of said household appliance.

[0157] Finally, the conductivity meter 1 of the invention and the installation method thereof allow for retrofitting and / or upgrading operations of household appliances already produced and in operation, consisting in the replacement of traditional electrical resistances with those integrating said conductivity meter 1.

Claims

CLAIMS1. Immersion metering device (1) of at least one physical quantity of a fluid, preferably service water circulating inside a household appliance and / or contained inside a reservoir or storage thereof, said at least one physical quantity being at least the electrical conductivity of said service water, said metering device (1) comprising:- one hollow tubular casing (10) closed at the tip by a cap (11), preferably made of insulating material,- at least a pair of electrodes (12; 12. a, 12. b) comprising one emitter electrode ( 12. a) and one receiver electrode ( 12.b), between which a voltage is applied for metering said electrical conductivity, and configured to interact with said service water,- an electronic interface board (3) comprising at least the devices (32; 33; 34; 35; 36; 37) and the related connections for the correct operation and management, via a microprocessor (36) thereof, of said electronic metering device (1), said interface board (3) comprising at least:- said microprocessor (36) capable of receiving, managing and processing said measurement of at least a physical quantity of a fluid and transmitting it to a control unit of said household appliance, connectors (34) for at least the power lines of said interface board (3) and / or the communication lines with said control unit of the household appliance, said communication lines comprising at least one line for the transmission of the metered electrical conductivity,-• a galvanic isolation system (31) for said electrodes (12; I2,a, 12.b), said galvanic isolation system (31) being placed between said interface board (3) and said electrodes (12; 12. a, 12.b) and comprising at least one pair of decoupling capacitors (31 ,n; 31.a, 31 ,b; 31 ,c, 31 ,d, 31 ,e),- one cable (13) connecting to said interface board (3) capable of electrically power said electrodes (12; 12. a, 12. b) and / or of transmitting the conductivity metering carried out to said interface board (3),characterised in that said metering device (1) is installed and integrated with an electrical resistance (2) for the heating and / or thermostating of a fluid circulating inside a household appliance and / or contained inside a reservoir or storage thereof.

2. Metering device (1) according to claim 1 , characterised in that both said electrodes (12; 12. a, 12.b) are housed on said cap (11), said electrodes (12; 12. a, 12. b) being projecting and protruding externally from said casing (10).

3. Metering device (1) according to claim 1 , characterised in that only one of said electrodes (12; 12. a, 12. b) is installed on said cap (11), said one electrode (12; 12. a, 12.b) being protruding externally from said casing (10).

4. Metering device (1) according to claim 3, characterised in that said one electrode (12; 12. a, 12.b) installed on said cap (11) is the emitter electrode (12. a), said receiver electrode ( 12.b) consisting of a metal component, connected to the ground, of the household appliance whereon said metering device (1) is installed.

5. Metering device (1) according to the previous claim, characterised in that, said receiver electrode (12. b) is a branch or coil (210) of an electrical resistance (2) used for the heating and / or thermostating of the sendee water of said household appliance.

6. Metering device (1) according to the previous claim, characterised in that said receiver electrode (12.b) is referred to the ground by means of a connection bridge (17) connected to the ground terminal (24) of said electrical resistance (2).

7. Metering device (1) according to claim 5, characterised in that said receiver electrode (12.b) is replaced by the ground by means of the ground terminal (24) of said electrical resistance (2).

8. Metering device (1) according to at least claim 1, characterised in that said galvanic isolation system (31) comprises at least one pair of decoupling capacitors (31.n, 31. a, 31 ,b; 31.c, 31.d, 31.e) and is integrated with said interface board (3).

9. Metering device (I) according to claim 1 or 8, characterised in that said decoupling capacitors (31.n; 31. a, 3 l.b; 31.c, 31 ,d, 31.e) consist of class ¥1 capacitors connected to said emitter electrode (12. a) and receiver electrode (I2.b).

10. Metering device (1) according to one or more of the previous claims, characterised in that said galvanic isolation system (31) comprises a pair of capacitors (31. a, 3 l.b), each placed substantially in the proximity or correspondence of a respective connection point (32; 32. a, 32. b) between said interface board (3) and said cable (13) of the conductivity meter (1).

11. Metering device (1) according to one or more of the previous claims, characterised in that said galvanic isolation system (31) comprises :--- a first pair of decoupling capacitors (31.c, 31.d) arranged in series with each other and with the emitter electrode (12. a), said decoupling capacitors (31.c, 31.d) being positioned in substantial proximity of the connection point (32. a) of said emitter electrode (12. a) on said interface board (3), and- a third decoupling capacitor (31.e) in series with the receiver electrode (12.b), adapted to connect to earth the connection point (32.b) of said receiver electrode (12.b) to the interface board (3).

12. Metering device (1) according to any previous claim, characterised in that it further comprises a filtering system (33) for at least said power supply and / or communication lines provided between said interface board (3) and said control unit of the household appliance, said filtering system (33 ) being integrated with said interface board (3).

13. Metering device (1) according to the previous claim, characterised in that said filtering system (33) comprises high frequency inductors (330).

14. Metering device (1) according to at least claim 1, characterised in that said connection cable (13) thereof is a double-insulated bipolar cable passing, at least in part, inside said casing (10) of said metering device (1).

15. Metering device (1) according to any previous claim, characterised in thatsaid casing (10) is made, at least in part, of quartz glass.

16. Metering device (1) according to one or more of the previous claims, characterised in that said microprocessor (36) of said interface board (3) comprises at least:--- one square wave generator (360) connected and placed upstream of said emitter electrode (12. a),-• one rectifier and peak detector (361) connected and placed downstream of the receiver electrode (12. b),-• one current detector or shunt (37) comprising a resistor (370) and placed between said receiver electrode (12. b) and said microprocessor (36).

17. Metering device (1) according to any previous claim, characterised in that it integrates at least one metering device (4, 40) of a physical quantity of said fluid, additional to said electrical conductivity, said additional metering device (4, 40) comprising at least one temperature sensor (40).

18. Metering device (1) according to one or more of the previous claims, characterised in that it integrates an accessory device (5, 50) capable of implementing a sanitising function of said fluid, said accessory device (5, 50) comprising one sanitising device (5, 50).

19. Metering device (1) according to at least claims 10 and / or 17, characterised in that said additional metering device (4, 40) and said sanitising accessory' device (5, 50) are installed on a printed circuit (15) inside the said casing (10) and connected to said interface board (3) via wiring (16), said interface board (3) therefore further comprising at least:-• connectors (34) for one or more communication lines for the transmission of the temperature measured by said at least one temperature sensor (40) to said control unit of the household appliance,- connection plugs (35) for said wiring (16) of said printed circuit (15).

20. Metering device (1) according to one or more of the previous claims from 17 onwards, characterised in that said additional metering device (4, 40) and said sanitising accessory' device (5, 50), installed in said printed circuit (15),are isolated from said fluid, preferably service water circulating or contained inside a household appliance, via said glass casing ( 10), and from said electrodes (12; 12. a, 12.b) by means of the aforementioned cap (11) made of insulating material and / or for the choice and presence of said doubleinsulated bipolar cable (13), said additional devices (4, 40) and / or accessories (5, 50) being placed at appropriate distance from said electrodes (12; 12. a, 12. b), comprised between 1 mm and 4 mm, preferably at least 2 mm or as required by law21. Metering device (1) according to one or more of the previous claims from 17 onwards, characterised in that:- said at least temperature sensor (4, 40) comprises an NTC or PTC thermistor,- said sanitising device (5, 50) comprises an ultraviolet emitter (50).

22. Electrical resistance (2) integrating said metering device (1) according to one or more of the claims 1 to 21, characterised in that on the flange (20) of said electrical resistance (2) a seat (23) is obtained for the installation of said metering device (1), said seat (23) comprising a through hole or slot (23) which develops by the entire thickness thereof between the face (200) which houses the electrical power connectors and the face (201) which supports the heating element (21), wherefrom said metering device (1) protrudes.

23. Household appliance comprising a metering device (1) according to one or more of the claims 1 to 21 and / or an electrical resistance (2) according to claim 22, characterised in that it consists of a washing machine or a washerdryer or a dishwasher or a storage water heater or a heat pump water heater or any other device comprising and operating with a fluid, preferably service water.

24. LTse of a metering device (1) according to at least the claims 1 to 21 for at least:- the metering of the electrical conductivity of a fluid, preferably water,- the metering of the temperature of said fluid,-• the sanitisation of said fluid from viruses, bacteria and / or other pathogenic microorganisms-• the activation / deactivation of at least one electrical resistance (2) for the heating and / or thermostating of said fluid, said functions being implemented and managed by said interface board (3) of said metering device (1) and / or by the control unit of said household appliance.

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