ITTO20010848A1 - ARRANGEMENT AND METHOD OF PURIFICATION OR ELECTROCHEMICAL TREATMENT. - Google Patents

Description

Description of the industrial invention entitled:

"ARRANGEMENT AND METHOD OF PURIFICATION OR ELECTROCHEMICAL TREATMENT"

DESCRIPTION

The present invention refers to an arrangement and to an electrochemical purification or treatment method, of the type indicated in the preamble of the attached claims 1 and 70.

The present invention proposes to indicate a new and efficient arrangement or purification or treatment device of the aforementioned type, which is of low cost and which has a long useful life, in the absence of maintenance interventions.

These and still other objects, which will become clearer hereinafter, are achieved according to the present invention, by an arrangement, or device, and a purification or electrochemical treatment method having the characteristics of the attached claims, which form an integral part of the present description. Further objects, characteristics and advantages of the present invention will become clear from the following detailed description and from the annexed drawings, provided purely by way of non-limiting example, in which:

- Fig. 1 represents the principle diagram of a first possible embodiment of a system for the purification of water made according to the present invention, in the case of a non-limiting application on a washing machine;

- Fig. 2 schematically represents a purification device forming part of the system of Fig. 1, used for the purpose of water softening or descaling; - Figs. 3-5 show, with different views, a first component of a purification device made in accordance with a first possible embodiment of the invention;

- Figs. 6-9 show, with different views, a second component of a purification device made in accordance with a first possible embodiment of the invention;

- Figs. 10-13 represent, with different views, a third component of a purification device made in accordance with a first possible embodiment of the invention;

- Fig. 14 represents, through a partial exploded view, a purification device realized by means of the components of Figs. 3-13;

- Figs. 15-17 represent, with different views, a first component of a purification device made in accordance with a second possible embodiment of the invention;

- Figs. 18-21 represent, with different views, a second component of a purification device made in accordance with a second possible embodiment of the invention;

- Figs. 22-25 represent, with different views, a third component of a purification device made in accordance with a second possible embodiment of the invention;

- Fig. 26 represents, through a partial exploded view, a purification device made by means of the components of Figs. 15-25;

- Fig. 27 represents, through a partial exploded view, a component of a purification device made in accordance with a third possible embodiment of the invention;

- Fig. 28 represents, through a plan view, an element forming part of the component of Fig. 27;

- Fig. 29 represents, through a partial exploded view, a purification device comprising the component of Fig. 27;

- Figs. 30-32 represent, with different views, a component of a purification device made in accordance with a fourth possible embodiment of the invention;

Fig. 33 represents, through a partial exploded view, a purification device comprising the component of Figs. 30-32.

The device and the method according to the invention will be described below, by way of non-limiting example, for the advantageous use for the purposes of softening or purification of at least part of the water used by a domestic appliance. The invention is also susceptible of advantageous use for other uses in a household appliance, as a system for recycling the water already used for washing, or also in other hydraulic systems or circuits for the electrochemical treatment of fluids or substances, in particular for the purpose of reduce or eliminate periodic maintenance interventions, through automatic washing with strongly acidic substances or strongly basic substances, in order to remove any deposits or residues that may form or deposit inside the system itself.

In general terms, the invention is susceptible of advantageous use in hydraulic systems or circuits for the electrochemical treatment of fluids or substances which require technical solutions that make it possible to simplify their structure and / or reduce costs and / or increase their duration without maintenance. .

In Fig. 1, 1 schematically indicates a treatment container or washing tank of a washing machine, comprising a system for the treatment or purification of a liquid according to the present invention, of the type in which at least one substance must be removed at least part of the liquid; in the exemplified case, the aforementioned system is provided at least to achieve the reduction of the degree of water hardness.

The washing machine illustrated consists of a generic dishwasher, in the tank 1 of which spraying means for the washing liquid are arranged, represented by two known rotating spray arms 2 and 3; 4 indicates a known washing or recirculation pump, designed to take the washing liquid from the bottom of the tank 1 and make it reach the arms 2 and 3 through a suitable conduit 5.

6 indicates a known drain pump, designed to evacuate the liquid used in the tank; a special drain pipe 7 is connected to the pump outlet 6 for this purpose. 8 indicates a duct for drawing water from a domestic water network, on which a filling valve 9 is provided; this valve 9 is of a type known per se and controlled by the machine control system, in order to allow the loading of the clean water necessary for washing, in the appropriate times and ways; on the duct 8 there can be provided sensor means, indicated schematically in MS, suitable for detecting some operating parameters of the incoming water, such as for example the flow rate, the pressure, the conductivity or resistivity, the temperature, the degree of hardness, of acidity or pH of the water, etc.

The duct 8, downstream of the valve 9, has a so-called air break device, or anti-backflow, or air-break, indicated with AB; downstream of the air gap AB, the duct 8 branches into two distinct ducts 8 A and 8B, which respectively feed a first tank P and a second tank S. Along the aforementioned ducts 8 A and 8B, upstream of the tank inlets P and S, respective valves of a per se known type are provided, indicated with 10 and 11, controlled by the control system of the machine.

The tanks P and S each comprise suitable sensor means; the sensors indicated with SPI and SS1 are designed to detect "quantitative" characteristics of the water present in the P and S tanks, such as flow rate, pressure, level, temperature, etc., while the SP2 and SS2 sensors are designed to detect characteristics " qualitative ”or electrochemical of the water present in the P and S tanks, such as conductivity or resistivity, degree of hardness, degree of acidity or pH, etc.

The tank P has a first outlet P1, in communication with the suction branch of a pump 12, of a per se known type and controlled by the machine control system, and a second outlet P2, in communication with a duct 13 for the supply of the water in tank 1 of the machine; a valve 14 of a known type and controlled by the machine control system operates on this outlet P2 of the tank P; the tank P also includes, at the outlet PI, a suitable filter, indicated with PF.

The tank S also has two outlets, the first of which, indicated by SI, is in communication with the suction branch of a pump 15, of a per se known type and controlled by the machine control system; the second outlet of the tank S, indicated with S2, is instead in communication with the aforementioned duct 13, for feeding the water into the tank 1 of the machine; a valve 16 of a known type and controlled by the machine control system operates on this outlet S2 of the tank S; also the tank S then includes, at the output SI, a suitable filter, indicated with SF.

It should be noted that the various valves of the described system are of the electric type and normally closed; therefore, for the purposes of this description, they must be considered in closed condition, unless otherwise specified.

The reference number 20 indicates as a whole a purification device, hereinafter also referred to as a decalcifier or softener, of the electrochemical cell or electrodialysis or electroosmosis type, which has in the lower part two inlet pipes 21 and 23, and in the upper part two outlet pipes 22 and 24.

The inlet pipe 21 is hydraulically connected to the delivery branch of the pump 12, while the inlet pipe 23 is hydraulically connected to the delivery branch of the pump 15; the outlet pipe 22 is hydraulically connected to the tank S or to the pipe 8B at a point downstream of the valve 10; the outlet pipe 24 is instead connected hydraulically to the tank P or to the pipe 8A at a point downstream of the valve 11.

The decalcifier 20 can comprise suitable sensor means, not shown in the figures, for detecting some "quantitative" and / or "qualitative" operating parameters, such as flow rate, pressure, conductivity or resistivity, temperature, degree of hardness, the degree of acidity or pH of the water entering and leaving the softener 20, etc. In Fig. 2 the purification device or decalcifier 20 is represented in greater detail, albeit schematically. This schematic representation must be intended only as an example and not limiting, and some details may be missing or in excess or made in a different way, except for the obtaining functions or performances similar to those inherent in the present invention.

In particular, the purification device or decalcifier 20 could provide different hydraulic configurations with respect to those illustrated, such as for example connections in parallel and in series between the various channels of the cell, and / or different types or arrangements of the various elements, such as for example the ion exchange membranes described below.

The device 20 comprises a body 20A, for example made of thermoplastic material; inside this body 20A, at its two longitudinal ends, respective main electrodes are arranged, and in particular a positive electrode or anode, indicated with 20B, and a negative electrode or cathode, indicated with 20C.

Between the anode 20B and the cathode 20C there are mounted suitable ion exchange membranes, of known type, for the definition of a series of channels inside the body 20A.

In particular, A indicates membranes permeable to anions, that is to ions having one or more negative electrical charges, which in an electrodialysis process, or in any case under the effect of an electric current or voltage, migrate to an anode; with C, on the other hand, are indicated membranes permeable to cations, that is to ions having one or more positive electric charges, which in an electrodialysis process, or in any case under the effect of an electric current or voltage, migrate to a cathode.

As can be seen, membranes A are alternated with membranes C, so that within the body 20A are defined:

- two "electrode channels", indicated with CE which, in the non-limiting example of Fig. 2, each extend between the anode 20B and a membrane C, and between the cathode 20C and a membrane C, respectively;

- at least one "Concentrate channel" CC, delimited by a membrane C and a membrane A; in the case shown as an example, three CC channels are provided; at least one "Product channel", designated CP, which extends between a membrane A and a membrane C; in the case shown, three CP channels are provided.

In the illustrated embodiment, moreover,

the channels CE are connected together in parallel, by means of an inlet manifold 30A and an outlet manifold 30B;

- the CC channels are connected to each other in parallel, both at their lower and upper ends, respectively to the inlet conduit 23 and to the outlet conduit 22;

- the CP channels are connected to each other in parallel, both at their lower and upper ends, respectively to the input conduit 21 and to the output conduit 24.

Again in Fig. 2, the symbols “+” and “-” indicate some intermediate electrodes, placed in correspondence with the CC and CP channels; in particular, intermediate electrodes "+" of positive polarity are provided in correspondence with the CC channels, while intermediate electrodes "-" of negative polarity are provided in correspondence with the channels CP; in the CE channel relating to the anode 20B an intermediate electrode of negative polarity is provided, while in the CE channel relating to the cathode 20C there is an intermediate "+" electrode of positive polarity. The aforementioned intermediate electrodes "+" and "-" are preferably connected in pairs with alternating polarity, connected together in parallel, so as to create an alternation of positive and negative polarity.

As will be clarified later, the aforementioned intermediate electrodes "+" and are used for the purpose of producing an acid directly from the water present in the purification device 20, for the purpose of cleaning the latter.

Returning to Fig. 1, 31 indicates a pump, of a type similar to those previously indicated with 12 and 15, whose delivery is in communication, through a duct 32, with the manifold 30A; the suction branch of the pump 31 is instead connected, through a duct 33, to the outlet manifold 30B; a tank 34 is preferably provided along the duct 33.

In a variant not shown, inlet and outlet ducts could be provided, with relative solenoid valves and sensor means also for the hydraulic circuit relating to the tank 34, in order to load and / or discharge the liquid circulating on the electrodes of the device 20 and / or detect its characteristics. In this perspective, the tank 34 can be of a configuration similar to the tanks P and S, and therefore

- in communication with the duct 8, through a respective inlet and a relative solenoid valve (not shown), of a type similar to the ducts 8A, 8B or the valves 10, 11, - in communication with the washing tank 1, through a respective outlet and a relative solenoid valve (not shown), of a type similar to the outputs P2, S2 or to the valves 14, 16

to allow periodic replacement of an electrode washing liquid, contained in the same tank 34 and / or in the hydraulic circuit relating to the electrodes 20B and 20C.

The dishwashing machine described above works as follows.

For the purposes of this operation, it is assumed that the tank 34 is also equipped with respective inlet and outlet, controlled by respective solenoid valves, as mentioned above.

Fig. 1 illustrates a condition for loading water from the water mains; this phase can for example be the first loading phase foreseen by a normal washing cycle of the machine incorporating the invention.

To this end, the machine control system provides for

- command the opening of valves 9, 10, 11 and the tank inlet valve 34,

- keep the valves 14, 16 and the tank outlet valve 34 closed,

- keep pumps 12, 15 and 31 inactive.

The water coming from the water mains can then travel through the duct 8, overcome the jump in the air AB and then go, through the ducts 8A and 8B to the P and S tanks, as well as to the 34 tank, through the respective inlet.

A certain amount of water is fed to the tanks P, S and 34, deemed sufficient for the purpose clarified below, after which the valves 9, 10 and 11 and the inlet valve of the tank 34 are closed; note that the dosing of the water inside the tanks P, S and 34, with the relative closure of the aforementioned valves, can be carried out with any known technique; for this purpose, each of the tanks P, S and 34 can be equipped with respective level sensor means (for example forming part of SS1 and SPI), such as for example a float sensor, a pressure switch or, preferably, a flow meter turbine, of a per se known type and operation.

During the loading of the tanks P, S and 34, the control system also checks the characteristics of the water through the sensors MS and / or SS2, SP2, designed to detect the conductivity or resistivity and / or the hardness and / or acidity or pH, etc., in such a way as to be able to automatically determine the amount of water required, and whether this should be treated with the softening system or whether it can be discharged directly from the tanks P and / or S into the washing tank 1.

In particular, the amount of water to be loaded into the tank S is automatically varied by the control system in proportion to the hardness of the water to be treated, that is, the water coming from the duct 8.

In the event that the water is of a hardness beyond the predetermined limits, it is first of all left to rest for a given period of time, for example a few minutes, during which any impurities present in the water itself can settle and settle in the lower areas of the P and S tanks, shaped like a well; such impurities can for example consist of sand, iron residues or rust, etc. After the aforementioned "decantation" period, the machine control system feeds pumps 12, 15 and 31.

In this way, the water present in the tank P is brought, through the pipe 21, to flow into the channels CP of the softener 20, and then re-enters the tank P through the pipe 24, given the closure of the valve 11; the same applies to the water present in the tank S which is brought, through the pipe 23, to flow into the CC channels of the softener 20, and then re-enters the tank S through the pipe 22, given the closure of the valve 10; the pump 31 instead determines the recirculation of a washing liquid, such as water, of the electrodes 20B and 20C, in the relative closed circuit.

Simultaneously with the activation of pumps 12, 15 and 31, the control system of the machine applies a continuous electrical voltage between the anode 20B and the cathode 20C of the softener 20.

In this way, the electric current flowing through the decalcifier 20 induces the migration of the Calcium and Magnesium cations, present in the water flowing in the CP channels, towards the cathode 20C, through the membranes C permeable to the cations; the anions instead migrate by the action of the electric current towards the anode 20B, through the membranes A permeable to anions.

In this situation, the cation-permeable membranes C prevent the anions from proceeding towards the anode 20B and the anion-permeable membranes A prevent the cations from proceeding towards the cathode 20C. This process therefore leads to a progressive decrease in the concentration of cations within the CP channels; in particular, as regards the purposes of the example, the cations that determine the hardness, such as calcium and magnesium cations, present in the CP channels are progressively transferred into the channels of the concentrate CC and into the CE channel of the cathode 20C.

In this way, during the softening process, some Calcium and Magnesium cations also migrate into the CE channel corresponding to the cathode 20C, from the CP channel adjacent to it, crossing the cationic membrane C which separates said channels from each other; the washing liquid of the electrodes is thus enriched with these cations.

Subsequently, during the recirculation of this electrode washing liquid, determined by the action of the pump 31, the same Calcium and Magnesium cations will reach the CE channel corresponding to the anode 20B; consequently, the same cations will then be induced to migrate, by electrolytic or electrochemical effect, into the CC channel adjacent to the said CE channel of the anode 20B, crossing the cationic membrane C which separates said channels from each other; the aforementioned Calcium and Magnesium cations are thus subtracted from the washing liquid of the electrodes, which pass into the water pertaining to the tank S, recirculated by means of the pump 15.

With this solution, an excessive concentration of Calcium and Magnesium cations in the electrode washing liquid circuit is therefore avoided, allowing to reduce the frequency of replacement of this liquid or in any case reducing the quantity necessary in order not to exceed the precipitation threshold for excessive concentration.

As can be seen, therefore, in a possible configuration of use of the system according to the present invention, the electrochemical softening process or by electrodialysis is preferably carried out in the presence of a recirculation of the water itself inside the purification device 20; this to determine a progressive reduction of the concentration of the ions present in the water or liquid contained in the tank P, which passes through the channels CP and, conversely, determine a progressive increase in the concentration of the ions present in the water or liquid contained in the tank S, that passes through the CC channels.

The softening or purification process, and therefore the aforementioned recirculation of the water between the tanks P and S and the purification device 20, as well as the recirculation of the water between the tank 34 and the purification device 20, can be carried out at time, ie for a predetermined period, or its duration can be programmed to carry out a given number of water passages through the device 20. Advantageously, this predetermined time or number of passages can vary according to the degree of hardness of the water at the entrance to the machine, detected for example by the sensor means MS. The machine control system can be advantageously programmed also in order to avoid carrying out the softening process, if the degree of hardness of the incoming water, measured by the MS sensor means, is already sufficiently low or lower than a value. predetermined.

When the descaling process is considered finished, the control system interrupts the application of the aforementioned electrical voltage between the anode 20B and the cathode 20C, as well as the power supply to the recirculation pumps 12, 15 and 31; therefore, inside the tank P there will be purified or softened water (hereinafter also referred to as Product), while in the tank S there will be water (hereinafter also referred to as Concentrate) having an increased content of ions (cations and anions), including the calcium and magnesium cations that contribute to forming the hardness.

Note that the previously described hydraulic system is designed in such a way that at least the various channels of the device 20 remain practically always filled with water, even after the interruption of the operation of the pumps 12, 15 and 31; in this way, even during the phases of rest or inactivity of the device 20, a certain amount of water is kept within the latter, such as to guarantee the immersion in the same of the membranes C and A, or in any case such as to maintain said membranes humid; this in order to prevent these membranes from drying out and therefore deteriorating.

At the end of the descaling process described above, the machine control system determines the opening of the valve 14.

In this way, the water contained in the tank P can flow into the duct 13, and from this to the tank 1 of the machine; it should be noted that the first part of this water which reaches the tank 1 contains any impurities possibly sedimented on the bottom of the tank P; these impurities, in any case, may be intercepted by a further filtering system of the apparatus or in any case be irrelevant in the typical operation of the dishwasher.

The dishes are then washed by means of the pump 4, the circuit 5 and the spray arms 2 and 3, in a manner known per se, followed by the discharge of the liquid used in the tank 1; this is obtained by activating the pump 6; for this purpose, of course, the control system is designed to supervise the typical operation of a washing machine.

Once the aforementioned drain has been completed, the machine control system provides for a new filling of water from the water mains, for the execution of the second phase foreseen by the washing cycle.

In a non-limiting example of the operating cycle, the control system of the machine controls the opening of only valves 9 and 11, keeping closed, in addition to valves 14 and 16, also valve 10; in this phase, the pumps 12, 15 and 31 are inactive. The water coming from the water mains can then go through the duct 8, overcome the jump in the air AB and then go, through the duct 8 A, to the tank P; it should therefore be noted that in the tank S and in the tank 34 the water that, in the previous phase of the cycle, had been used for descaling purposes is stored.

When the necessary quantity of water is loaded in the tank P, the valves 9 and 11 are closed, and the water loaded in the same tank P is left to "settle", as explained above, after which the control system of the machine power up pumps 12, 15 and 31.

Again, therefore, the water present in the tank P is brought, through the pipeline 21, to flow into the channels CP and then re-enters the tank P, through the pipeline 24 and given the closure of the valve 11; the water present in the tank S is brought, through the pipeline 23, to flow into the CC channels, and then re-enters the tank S, through the pipeline 22 and given the closure of the valve 10.

Simultaneously with the activation of the pumps 12, 15 and 31, the control system of the machine also provides for applying the aforementioned direct electrical voltage between the anode 20B and the cathode 20C of the softener 20, in order to carry out the descaling of the water contained in tank P, in the manner already described above. This softening process in constant recirculation therefore determines the progressive reduction of the degree of hardness of the water in the tank P, which passes through the channels CP; through the same process, on the other hand, a further progressive increase in the degree of hardness of the water in the S tank is obtained.

When the descaling process is considered finished, the control system interrupts the application of the aforementioned electrical voltage between the electrodes 20B and 20C and the power supply to the recirculation pumps 12, 15 and 31; Inside the tank P there will therefore be softened water, while in the tank S there will therefore be water further loaded with Calcium and Magnesium cations.

The machine control system then determines the opening of the valve 14, so that the water contained in the tank P can flow into the duct 13, and from this reach the tank 1 of the machine; the dishes are then washed as in the previous phase, with methods known per se.

The same water filling and descaling process, as previously described, is then repeated for all the phases foreseen by the washing cycle.

From the above it is clear that, according to the proposed solution, the same water originally loaded in the tank S is used for carrying out several water softening phases, each time loaded into the tank P; the solution according to the invention therefore allows to substantially reduce the amount of waste water resulting from the descaling process. Alternatively, it would still be possible to empty the tank S, and its subsequent filling with water from the network, concurrently with each emptying and filling cycle of the tank P; in this case the volume of water loaded each time in the tank S will be lower than the example described above, but such as to receive the substances extracted from the liquid contained in the tank P, without causing excessive concentration or precipitation phenomena.

The water contained in the tank S, and used during the descaling processes that occur during the various water loads from the water mains, can be discharged from the machine at the end of the washing cycle. In a possible advantageous embodiment of the invention, however, the water contained in the tank S could be kept, at the end of a washing cycle, inside the same tank or inside the washing tank, to be then used during the course. of a subsequent use of the device or a phase of the next washing cycle. The contents of the tank S can also be exploited for the purpose of carrying out certain phases envisaged by a washing cycle, when in these phases the use of water even with a high degree of hardness is considered acceptable, such as, for example, phases of the cycle carried out with cold water, or with water having a temperature lower than the limestone precipitation threshold.

In the preferred form of the invention, for the purposes of making the decalcifier 20, several pairs of cationic membranes C and anionic A (for example thirty pairs) are provided, with the addition of a terminal cationic membrane, so that towards the ends 20B and 20C face only the cationic membranes C. The use of membranes of the same type, for example cationic (but could also be anionic) at the two ends of the decalcifier 20 allows the ions, in the present example to the cations, passed from the last CC channel towards the CE channel of the cathode 20C to be then expelled towards the opposite CC channel, when they recirculate in the CE channel of the anode 20B.

The system responsible for controlling the device according to the invention can advantageously be programmed to periodically reverse the polarity of the end electrodes 20B and 20C provided in the decalcifier 20.

In a possible embodiment, the aforementioned polarity inversion can take place for a fixed time at the end of each single descaling process (for example for a time equal to 10% of the total treatment time); in these conditions the water in the CP channels, where the surfaces of membranes C and A may be encrusted, is softened and therefore clean, while the water in the CE and CC pipes has an enriched content of Calcium and Magnesium cations.

In this regard, other operating modes could in any case be envisaged, such as for example multiple polarity inversions during the entire descaling process, using fixed times or variable durations depending on the continuous measurements on the hardness of the mains water, the water pertaining to tank S and water pertaining to tank P, these measurements being carried out by means of MS, SS2 and SP2. In a configuration considered preferential, with reference to the aforementioned polarity inversion of the electrodes 20B and 20C, the described softening system is also designed to alternate the functions of the tanks S and P or to vary the hydraulic configurations in order to reverse the circuits .

As seen above, the tank P is in normal conditions intended for containing the water to be softened, whereas the tank S is instead intended for waste water from the descaling process; however, according to the proposed variant, it is also possible to think of carrying out the aforementioned polarity inversion of the electrodes not for a single portion of a descaling process, but on the contrary for its entire duration. According to this embodiment, an inversion of the hydraulic circuits and / or of the relative functions also corresponds to said inversion of the electrical polarity; therefore, to a descaling process as previously described, where the electrode 20B acts as an anode, the electrode 20C acts as a cathode, the tank P collects the water to be softened and the tank S collects the water in which the cations from the water of the tank P, then follows a descaling process with reversed polarity and reversed CC and CP channels, in which the electrode 20B acts as the cathode, the electrode 20C acts as an anode, the tank S collects the water from soften and the tank P collects the water in which the cations migrate from the water of the tank S.

In this process, following the filling of tanks P and S, and the subsequent "decanting" period, the machine control system supplies the pumps 12, 15 and 31. In this way, the water present in the tank P is brought, via the conduit 23, to flow into the channels CP of the softener 20, and then re-enters the tank P via the conduit 24, due to the closure of the valve 11; the same applies to the water present in the tank S which is brought, through the pipe 21, to flow into the channels of the electrodes CE and into the channels CC of the softener 20, and then re-enters the tank S through the pipe 22, given the closure of the valve 10.

Simultaneously with the activation of pumps 12, 15 and 31, the control system of the machine applies a continuous electrical voltage between the electrode 20B, which now acts as a cathode, and the electrode 20C, which now acts as an anode.

In this way, the electric current flowing through the decalcifier 20 induces the migration of the Calcium and Magnesium cations, present in the water flowing in the CC channels, towards the electrode 20B, through the membranes permeable to the C cations; the anions migrate by the action of the electric current towards the electrode 20C, through the membranes permeable to anions A. In this situation, the membranes C permeable to the cations prevent the anions from proceeding towards the electrode 20C and the membranes A permeable to the anions they prevent the cations from proceeding towards the electrode 20B. This process therefore leads to a progressive decrease in the concentration of cations within the CC channels; in particular, with regard to the purposes of the present invention, the Calcium and Magnesium cations present in the CC channels are progressively transferred into the CP channels and the CE channels of the electrode 20B, in the same manner as previously described.

As can be seen, also in this case the electrochemical softening process or by electrodialysis is carried out in the presence of a recirculation of the water itself inside the softener 20; this to determine a progressive reduction of the degree of hardness of the water contained in the tank S and, conversely, to determine a progressive increase in the degree of hardness of the water contained in the tank P, which passes through the channels CP.

The electrochemical purification process described above can give rise to the precipitation of salts inside the channels of the decalcifier 20, which can cause clogging of the same. For this reason, according to the main aspect of the present invention, an electrochemical self-cleaning system of the decalcifier itself is provided, to be activated for a short time, when the clogging appears or in any case in good time before a decay occurs in the performance of the water softener 20.

The precipitate that forms inside the various channels of the decalcifier 20 is mainly formed by calcium and magnesium salts insoluble in water; however, these salts are soluble in an acid environment.

The intermediate electrodes "+" and previously mentioned are part of the aforementioned electrochemical self-cleaning system and in particular have the function of determining the formation of a cleaning acid, directly inside the purification device 20, and in particular in the channels where the concentration of ions tends to increase and where the aforementioned precipitated salts tend to accumulate.

In the previously exemplified case, where a first purification cycle is carried out, concentrating the ions in the CC channels and in one of the CE channels, and a second purification cycle with an inverted configuration, concentrating the ions in the CP channels and in the other CE channel, it will be necessary to carry out two distinct self-cleaning cycles, forming acid in the channels which last underwent an increase in the concentration of ions.

Preferably, the intermediate electrodes "+" and

they are alternated to operate in pairs (+ and -) on only one type of the two membranes A or C, preferably the cationic membranes C as they are more resistant to electrochemical action;

they are made with a low cost, preferably in plastic, or in electrically conductive rubber, or in fibers of conductive materials, such as graphite or carbon, since the number of such intermediate electrodes is high and the number of their working hours is relatively small;

they are made with a shape and / or material such as not to provide a preferential or short-circuit path for the current flowing between the main electrodes 20B and 20C of the device 20; vice versa, the electric current would no longer pass through the liquid solution (Product and Concentrate, where the concentrate has greater electrical conductivity), finding a preferential path in the thickness of the intermediate electrodes "+" and "-" this drawback is avoided according to the invention by realizing the intermediate electrodes "+" and "-" with a material having an electrical resistance higher than that of the said solution (Product and Concentrate) and / or ensuring the presence of a space or "gap" between the intermediate electrode and the ion exchange membrane, so that the liquid to be treated can circulate in this space. As a purely indicative, therefore, the intermediate electrodes "+" and "-" could be shaped like a mesh, or in any case have a porous structure that allows the liquid and / or ions to pass through them, and also having the function of spacers or support walls for ion exchange membranes, or of a composite structure, for example partly in electrically conductive plastic and partly in an electrically conductive mesh or fabric (such as in carbon fiber or graphite or other material electrically conductive suitable for the purpose), held together or pressed in electrical contact or glued or welded or co-molded, or in electrically conductive plastic overmolded to a metal core, to improve the uniform distribution of the current in long paths, or integral, or in any case combined with the ion exchange membranes, and then put in contact with one or more bars or elements of contact or electrical distribution, for example impio made of electrically conductive plastic co-molded with a respective electrically insulating membrane support element; also for these last configurations all the materials and / or manufacturing technologies previously described or in any case suitable for the purpose can be provided.

Some examples of embodiment of the aforementioned intermediate electrodes "+" and "-" will be described below.

In the system according to the invention, with reference to the configuration indicated in Fig. 2, from a chemical point of view, the application of an electric voltage to the intermediate electrodes "+" and "-" of the purification device 20 gives rise to the following phenomena: CC Concentrate Channels (with positive polarity "+" intermediate electrodes)

Acid is formed in these channels according to the reaction:

that is a sort of oxidation, where from two water molecules four Hydrogen H <+> ions are obtained (which determine the acidity), with the simultaneous formation of an Oxygen molecule (02), which is released into the air ( or possibly catalyzed in a known way to recombine it in water).

According to this reaction, an acidic environment will occur in the CC channels; this acid solution is used to solubilize the salt deposits present inside the purification device 20 (for example CaC03, MgC03,) according to the reaction:

where M <2+> is the generic divalent cation responsible for the precipitation of the aforementioned salts (Ca <2+>, Mg <2+>).

In order to obtain a high concentration of hydrogen ions H <+>, necessary to dissolve the aforementioned saline deposits, during the self-cleaning cycle, the CC channels preferably work in static conditions, i.e. in the absence of hydraulic recirculation in the softener 20.

Product channels CP (with intermediate electrodes of negative polarity) In these channels a base is formed accordingly according to the reaction:

that is a sort of reduction, where two hydroxyl ions OH <'> (which determine basicity) are obtained from two water molecules, with the simultaneous formation of a hydrogen molecule (H2), which is released into the air (or possibly catalyzed to recombine it with the previously mentioned oxygen molecule 02, in order to form water and avoiding discharging gas into the environment).

According to this reaction, therefore, in the channels of the Product CP there will be a basic environment (with high pH); this basic solution can favor the further precipitation of the cations present in low concentration in the CP channels, with the formation of MC03 and M (OH) 2.

In order to avoid or reduce said pH increase, and therefore the risk of precipitation of the cations present in the solution, during the self-cleaning cycle the CP channels (unlike the previously mentioned CC channels) preferably operate with the hydraulic recirculation activated (conditions dynamics), so as to dilute the OH <"> ions, produced in the few cubic centimeters of solution contained in the purification device 20, in the high volume of water present in the recirculation tank P. In this way, therefore, in the device 20 the liquid is preferably kept in static conditions where a high concentration of acid is to be obtained (channels to be washed) while a recirculation is maintained where a low concentration of the base is to be maintained (opposite channels, where unwanted precipitations are to be avoided).

It should be noted that when polarity inversion is used for the descaling cycle (where, as previously described, the electrical inversion of the electrodes 20B and 20C also corresponds to a hydraulic inversion of the CC and CP channels - in the sense that the that previously were of the Product now become of the Concentrate and vice versa), the control system will store the information relating to the last polarity used, so as to know which were the last channels of the Concentrate, or the last channels in which it was had an increase in the concentration of ions, and the last channels of the Product, or last channels in which there was a decrease in the concentration of ions; also for the two EC electrode channels it is important to know the last polarity used, as Calcium, Magnesium tend to accumulate more on the last electrode used with negative polarity.

With the polarity inversion of the electrodes 20B and 20C, residues or precipitates accumulate in any case in all the channels of the decalcifier 20 and this requires a first cycle of self-cleaning with acid of a first group of channels (for example the last ones used as a Concentrate) and a second self-cleaning cycle with acid of a second group of channels (for example the last ones used as a Product, which however have previously also operated as Concentrate channels in other descaling cycles).

Preferably, said first and second self-cleaning cycles are not carried out in succession, for reasons that will be clarified below, but each carried out after a respective operating cycle of the device 20 as a purification system, so that in the channels to be cleaned, where the acid is formed, the solution enriched with ions or Concentrate is present, while in the opposite channels, where the basic solution is formed, there is purified water.

To carry out the first of said two self-cleaning cycles, the intermediate electrodes "+" "-" are connected with polarity of a first type, while to carry out the second of said two self-cleaning cycles, the intermediate electrodes "+" "-" are connected with opposite polarity to the previous one.

As mentioned, in the non-limiting example shown in Fig. 2, the intermediate electrodes "+" "-" are preferably connected in pairs with alternating polarity, connected to each other in parallel, so as to create an alternation of positive and negative polarity ; this configuration makes it possible to use a low direct voltage, particularly useful in the household appliance sector in order to avoid the risk of electrocution due to accidental dispersions; alternatively, however, different electrical connections could also be made, in any case suitable for the purpose.

The aforementioned self-cleaning treatment of the decalcifier 20 is preferably, but not necessarily, carried out with the same aqueous solution present in the various ducts CE, CC and CP at the end of the purification treatment, where the Concentrate and Electrode channels are enriched by ions extracted from the Product channels, which consequently remain impoverished.

In these conditions, the lack of ions in the CP Product channels, where the water would then tend to become basic during the self-cleaning treatment (even if this phenomenon is reduced with recirculation), consequently reduces the risk of precipitation of the salts; vice versa, in the concentrate, even if there are many ions, precipitation does not occur following the formation of an acid during the self-cleaning treatment. For this reason, and following the aforementioned need to wash all the ducts that have alternated from time to time in reversed polarity operation, it is advisable for the system to carry out a washing in a first way (Product and Concentrate channels in a first configuration) at the end of a descaling that ends with a first polarity, and which then carries out a further washing in a second way (Product and Concentrate channels in the opposite configuration) at the end of a further descaling that ends with a second polarity opposite.

For information, the aforementioned depletion of ions in the Product channels determines a reduction in the conductivity of the relative liquid, while an increase in the ions in the Concentrate channels determines an increase in the conductivity of the relative liquid.

At the end of the descaling process, a sort of electrical circuit is created (between the two end electrodes 20B and 20C or between the intermediate electrodes "+" "-") consisting of an alternating series of high (Product) and low resistances (Concentrated) value (ohm), which series also includes the interposition of the electrical resistances introduced by the ion exchange membranes C and A; the resistance of the membranes is however of a relatively constant value, unlike the electrical resistance of the liquid, which varies as a result of the displacement of the ion concentrations.

With regard to these changes in resistance, the increase in the resistance of the Product channels (depletion of ions) is proportionally higher or in any case different from the relative decrease in the resistance of the Concentrate channels (increase in the concentration of ions); in this way the total resistance, given by the series of resistances of the Product and Concentrate, increases during the progress of the descaling (as the imbalance of the ions between the said channels increases). In this regard, however, it should be noted that, for example in the domestic and / or food sector, it is not necessary, if not forbidden, to reach excessively low purification or conductivity values (total removal of dissolved ions or salts). In the exemplary case of the present invention, therefore, the decalcified water that remains in the Product channels still has a certain residual hardness, which allows an electric current to circulate between the intermediate electrodes "+" "-" in order to obtain the already described electrochemical phenomena suitable to produce the cleaning acid, even without the risk of triggering said precipitation phenomena.

The control system that supervises the operation of the device 20 will be programmed to activate the self-cleaning cycle described according to the various conditions and / or actual needs, for example by carrying out various measurements using sensors (hardness, flow, etc.), and / or by storing and processing the data relating to the previous purification operation of the device itself, detecting, for example, variations in the flow rates and / or electrical absorption, or by varying the self-cleaning cycle in relation to the previous purification cycle.

In a possible embodiment, a flow sensor is provided for this purpose, preferably a sensor for each hydraulic circuit (CC, CP, CE), suitable for detecting the variations in the flow rate of the liquid circulating in the various channels of the electrochemical cell, in so as to be able to detect any clogging due to deposits or precipitates, and activate the self-cleaning cycle only when it is actually needed.

Preferably, the control system verifies said information deriving from the foreseen flow meter or meters and processes it, for example together with data relating to any decreases in the electrical absorption of the device 20 (attributable, for example, to deposits on the exchange membranes ionic), in order to activate or not the self-cleaning cycle.

In other conditions, however, for example in the case of the formation of bio-films (biological films that proliferate in conditions of stagnant water), it might be preferable to carry out an early cycle of self-cleaning and / or disinfection, even if a low hardness incoming water would not seem to require it.

It should be noted that, in a possible variant embodiment of the purification device 20, intermediate electrodes "+" "-" may not be provided in the channels CE. In this variant, the aforementioned missing intermediate electrodes are in fact replaced by the two end electrodes 20B and 20C normally used for descaling; in this embodiment, the electrodes 20B and 20C are connected to the intermediate electrodes of equal polarity by means of a suitable switching circuit, for example made by means of electronic switches or switches.

The self-cleaning cycle of the device 20 preferably provides for the solution formed by means of the electrodes "+" and "-" to be kept for a short period inside the various channels CE, CC and CP, to then be evacuated, by means of of the new liquid added to the same channels which rinses it; this new rinsing liquid can for example be fed into the channels CE, CC and CP with the same means and methods described with reference to the operation of the machine of Fig. 1. For example, this rinsing can be carried out with clean water or with water waste (i.e. pertaining to the tank circuit S), in order to evacuate the cleaning solution or acid and the residues / encrustations that have been dissolved there; this rinsing liquid of the device 20 can be evacuated into the tank 1 or directly into the discharge duct of the machine 7, together with the same solution used for cleaning the device 20.

It should also be emphasized that the cleaning of the device 20 according to the invention is in no way comparable to the regeneration of the resins provided by traditional type descalers; in the case of the present invention, the substance or solution used is in fact intended to dissolve any encrustations or deposits on the walls of the ion exchange membranes, while in the case of resin softeners the ions of the regenerating compound (usually a solution of water and salt) are to replace, undermining them, the ions previously absorbed and retained by the resins.

As mentioned, the self-cleaning cycles of the device 20 are possible, and in any case carried out automatically only periodically, when a clogging or near-clogging situation of the device itself is detected or estimated (for example with intervals of tens of operating days of the machine washing cycle of Fig. 1, if this is used several times a day and with water at the highest levels of hardness, according to sector specifications); the passage section of the various ducts CE, CC and CP is also extremely small (in the order of a few millimeters) and, consequently, the quantity of washing solution to be used for each self-cleaning cycle of the device 20 is very limited ( for example in the order of a few tens of cubic centimeters of concentrated acid, further diluted in water taken from the hydraulic circuit).

In Figs. 3-14 shows some of the components used for making a first version of the purification or decalcifier device 20; it should be noted that in these figures the intermediate electrodes "+" "-" have not been shown, for greater clarity of representation.

In Figs. 3, 4 and 5, 40 indicates as a whole an end or head body, preferably made of molded thermoplastic material, provided with strengthening ribs 41 and holes 42 for tie rods, for example in the form of simple threaded rods at the extremities to be able to be put in traction, for the purposes that will be clarified later; alternatively, the aforementioned tie rods could be made of thermoplastic material, in particular of the type able to withstand tensile stresses, which tie rods could then be welded or deformed at their ends, for example by hot deformation or vibrations, in order to put in traction the said heads and compress the elements interposed therewith.

The head 40 integrates a series of through fittings, inlet and outlet for a fluid subject to treatment, such as water, and in particular a first inlet 44, a first outlet 43, a second inlet 46 and a second outlet 45.

The flat part of the head, indicated with PP, located in proximity to the fitting 46 is substantially the supporting base of the device 20; the fittings located near this PP part are therefore located at the bottom of the device and are preferably fluid inlets, so that the outlets are located in the upper part, to facilitate the escape of any gases that may form inside the device itself.

An electrode is indicated with 47, which for simplicity is assumed to be the cathode previously indicated with 20C, which is integrated in the head 40 and is equipped with an electrical terminal, schematically indicated with 47A.

In Figs. 6, 7, 8 and 9 show an end support element, indicated as a whole with 50, preferably made of molded elastic material (for example silicone or thermoplastic rubber).

As can be seen in Fig. 6, on its first side 50A, the support 50 is provided with two first channels 51A and 51B, which branch out respective second channels 52A and 52B; the second ducts 52A and 52B branch out into further third ducts 53A and 53B respectively, which flow into an opening or central chamber 54 of the support 50, in correspondence with which a membrane C is intended to be mounted, as will be clarified hereinafter; the aforementioned first, second and third channels are substantially in the form of grooves defined on the surface of the side 50 A of the support 50.

The width of the third ducts 53 A and 53B is deliberately limited, in order to avoid points of yielding or bending of the membrane C in correspondence with these points; consequently the number of these third channels is sufficiently high in order to guarantee in any case a suitable passage section for the fluid to be treated.

It should be noted that the aforementioned first, second and third channels open only on the side 50A of the support 50, leaving the opposite side 50B closed or blind.

The support 50 also comprises two series of passages 55 A and 55B, defined along opposite sides of the central opening 54, these passages 55A and 55B being isolated with respect to the aforementioned first, second and third channels, in particular by means of sealing elements obtained therein. support body 50.

As can be seen in Fig. 7, on the side 50B of the support 50, on which a membrane C is intended to be placed, has a lowered seat SR, provided with at least one sealing lip 56, which extends along the entire edge of the central opening 54; two of said sealing lips 56 are preferably provided, located concentrically in order to increase the safety level in the event of any defects on one of the two lips.

The seat SR, designed to receive the edges of the ion exchange membrane, has a predefined depth and is able to compensate for a part (about half) of the thickness of the membrane itself, while ensuring that this can in any case be compressed in seal between two adjacent supports. (as will appear later), without causing an excessive thickness that would compromise the total seal of the device. In this regard, it should be considered that, for a number of thirty pairs of membranes, any deformation of a few tenths, for example caused by the thickness of each membrane, causes a total deformation of several millimeters.

The support 50 is also provided with external perimeter lips, indicated with 57A and 57B, respectively on its two opposite sides 50A and 50B, in order to guarantee a seal towards the outside, and is also provided with lips 58 which surround the passages 55A and 55B.

The central opening 54 of the support 50 also houses a dividing element, not shown here, for example in the form of a braided wire mesh, designed to keep the ion exchange membrane C mounted in correspondence with the electrode 47 and in position. opening 54, as will be described hereinafter, while allowing a flow of water to pass.

In Figs. 10, 11, 12 and 13 show an intermediate support element, indicated as a whole with 60, preferably made of molded elastic material (for example silicone or thermoplastic rubber).

The intermediate support 60, similar in many respects to the end support 50, is provided with two first series of channels 61A and 61B, placed along two opposite sides of a respective central opening 62, and with two second series of channels 63A and 63B , placed along the other two opposite sides of the central opening 62; the channels 63A and 63B are hydraulically connected, by means of the channels 64A and 64B, to the same central opening 62; also in this case, in correspondence with the central opening 62 there is also a respective dividing element, such as for example a mesh (not shown), having functions similar to that previously mentioned with reference to the support 50.

As can be seen in Fig. 11, the side 60B of the support 60 is provided with at least one sealing lip 66 (preferably two sealing lips are provided, as in the case of the support 50), which extends along the entire edge of the opening central 62; at least one similar lip, indicated by 67 in Fig. 10, is also provided on the side 60A of the support 60; this lip 67, even if interrupted in some points by the presence of the channels 64A and 64B, nevertheless serves to guarantee a counterthrust on the ion exchange membrane with respect to the continuous lip 56 of the adjacent support 50 (see Fig. 7) or with respect to the continuous lip 66 present on the opposite side 60B of the adjacent intermediate support 60 (see Fig. 14), so as to improve the seal on the ion exchange membranes C and A.

On this point, it should be noted that also on the sides 60A and 60B of the support 60, there are respective lowered seats SR, provided with the lips 66 and 67, which extend around the central opening 54, for the positioning of the edges of the ion exchange membranes. .

The support 60 is also provided with external perimeter lips, indicated by 68, placed on the side 60 A, in order to guarantee a seal towards the outside, and is provided with lips 69 which surround the series of channels 61 A and 61B, at the in order to ensure a seal between the same channels and the opening 62, the channels 63A, 64A and 63B, 64B and towards the outside.

Both the support elements 50 and the support elements 60 have perimeter through holes FP, positioned congruently with the holes 42 of the head 40.

Fig. 14 shows a partial exploded view of a possible embodiment of a purification device 20, formed by the components of Figs. 3-13 above. It should be noted that in this example, for simplicity of description, a reduced number of supports 50, 60 and membranes A and C are provided; in the practical implementation of the invention, however, these components will be in a much higher number (for example, at least thirty pairs of support elements 60, with respective membranes C and A can be provided).

The two ends of the purification device 20 of Fig. 14 are formed by respective heads 40 which, for greater clarity, are indicated in the figure with 40 'and 40 ". Note that the two heads 40 'and 40 "are placed so that the respective surfaces bearing the electrodes 47 are facing each other, the heads being tilted 180 ° relative to each other.

Between the two heads 40 'and 40 "the support elements 50 and 60 are interposed, where a respective end support is placed adjacent to each head 40' and 40", indicated here for greater clarity with 50 'and 50 "; between the end supports 50 'and 50 "are in turn placed pairs of intermediate supports, indicated here with 60' and 60".

As can be seen, the end supports 50 'and 50 "are arranged in such a way that the respective sides 50A, on which the channels 51A-51B, 52A-52B and 53A-53B are defined, face the surface of the respective head 40 'and 40 ”bearing the electrode 47, the two elements 50' and 50” being oriented at 90 ° with respect to each other.

The intermediate support elements 60 'and 60 "are instead arranged so that the side 60A of the element 60' faces the side 50B of the element 50 'adjacent to it, and the side 60B of the element 60" faces towards the side 50B of the element 50 "adjacent to it, with the element 60 'mounted in the same direction but rotated by 90 ° with respect to the element 60".

Between the support 50 'and the support 60', as well as between the support 50 "and the support 60" there is a membrane C, in correspondence with the SR seats of the respective central openings 54 and 62; between the two adjacent 60 'and 60' supports there is instead a membrane A, corresponding to the SR seats of the respective central openings 62.

The unit thus formed (also including the intermediate electrodes and the mesh dividers, previously cited but not represented here), is assembled and packed by means of tie elements (also not shown) or other elements suitable for the purpose. These tie rods, as mentioned, can for example be simple bars passing through the holes 42 of the heads 40 'and 40 "and into the holes FP of the elements 50', 60 ', 60", 50 ", threaded at the ends in order to be placed in traction; in a possible variant, there may be bands (metal or plastic) surrounding the device 20 compressing the said supports 50 ', 60', 60 ", 50" through the two heads 40 'and 40 ".

In the above way, the edge of the membranes C is interposed between the lips 56 of the supports 50 'and 50 "and the lips 67 and 67 of the supports 60' and 60", while the edge of the membrane A is interposed between the lips 67 of the support 60 "and the lips 66 of the support 60 '. It should be noted, in particular, that this type of construction makes it possible to minimize the portion or edge of membrane A or C necessary to maintain it in position, as well as to provide the respective hydraulic seal (the latter being made, depending on the cases, via the continuous lips 56 or 66).

As a result of the aforementioned arrangement, therefore, in the device 20 of fig. 14 various channels are formed:

First electrode channel

The water that is pushed through a pump (with a function similar to the pump 31 in Fig. 1) into the inlet 46 of the head 40 'reaches the central opening 54 of the support 50', through the first, second and third channels 51 A, 52A and 53 A of the latter (these ducts are not visible in Fig. 14); the same water then crosses this opening 54 in a transverse direction, to pass through the third, second and first channeling 53A, 52B and 51B of the same support 50 ', and then reach the exit 45 of the head 40'.

Second electrode channel

The water that is pushed through a pump (with a function similar to pump 31 in Fig. 1) into the inlet 46 of the 40 "head reaches, through the first, the second and third channels 51 A, 52A and 53 A (not visible) of the respective support 50 ", the central opening 54 of the latter; the same water then crosses this opening 54 in a transverse direction, to pass through the third, second and first ducts 53A, 52B and 51B of the same support 50 ", and then reach the outlet 45 of the head 40".

CP Product Channel

The water which is pushed through a pump (with a function similar to the pump 12 of Fig. 1) into the inlet 44 of the head 40 'reaches, through the passages 55 A (not visible) of the respective support 50', the channels 63B of the 'intermediate support element 60'; from these channels 63B, the water passes, through the respective channels 64B, into the central opening 62 of the same support 60 ', to cross it; the water then reaches the channels 64 A of the same support 60 ', and therefore the channels 63 A. From these channels 63 A, the water can then reach, through the passages 55B of the support 50', the outlet 43 of the head 40 '.

Note that, in the exemplified case, the water can also reach the channels 61B and 61A of the support 60 ", which are however closed in the direction of the head 40" through the side 50B of the end support 50 ".

If the device envisages further intermediate support elements with respect to what is illustrated in Fig. 14, the channels 61B and 61A of the element 60 "shown would be connected in series with the channels 63B and 63A of a further intermediate support element 60 , so as to form two manifolds which respectively feed in parallel the channels 64B of the various intermediate support elements of the same type and receive the outgoing flow from the relative channels 64A.

Concentrate Channel CC

The water that is pushed through a pump (with functions similar to the pump 15 in Fig. 1) into the inlet 44 of the 40 "head reaches, through the passages 55A of the respective support 50", the channels 63B of the intermediate support element 60 "; from these channels 63B, the water passes, through the respective channels 64B, into the central opening 62 of the same support 60 ", to cross it; the water then reaches the channels 64 A of the same support 60 ", and then the channels 63A. From these channels 63A, the water can then reach, through the passages 55B of the support 50 ", the outlet 43 of the head 40".

In the exemplified case, the water can also reach the channels 61B and 61 A of the support element 60 ', which are however closed in the direction of the head 40' through the side 50B of the end support 50 '.

Also in this case, if the device envisages further intermediate support elements with respect to what is illustrated in Fig. 14, the channels 61B and 61A of the element 60 "shown would be connected in series with the channels 63B and 63A of a further Support element intermediate 60, so as to form two manifolds which respectively feed in parallel the channels 64B of the various support elements of the same type and receive the outgoing flow from the relative channels 64A.

Note that, in the example of Fig. 14, the first and second electrode channels are independent and connected to each other externally to the softener 20, to a respective water recirculation circuit. Naturally, the two electrode channels could be connected to each other internally to the decalcifier 20, for example with through holes in the various supports 50 and 60; to obtain this, configurations similar to those envisaged for connecting the channels of the supports themselves can be used.

In an example of non-limiting use, the decalcifier 20 of Fig. 14 is arranged in use in such a way that the fittings 44 and 46 are located in the lower part, while the fittings 43 and 45 are located in the upper part; this in order to facilitate the outflow of gases (upwards) that may form in the cell during operation. According to said improving arrangement, i.e. according to the specular structure of the body of the heads 40, the decalcifier 20 is therefore preferably mounted in an angled position, such as to be substantially like a rhombus (i.e. with one of the vertices facing downwards), so that both inlets or outlets are oriented downwards, although they are slightly angled to each other.

In Figs. 15, 16 and 17 illustrates a head 40 made in accordance with a possible variant embodiment of the invention; in these figures the same numbers as in the previous figures are used to indicate technically equivalent elements.

According to this variant, the ducts previously indicated with 51A-51B, 52 A-52B and 53A-53B are made directly on the surface of the head 40, instead of on the end support 50, the latter thus presenting on its side 50A a substantially flat surface. In this variant, moreover, small supports PS are provided in correspondence with the channels 52A-52B, to better support the end support 50.

In Figs. 18, 19, 20 and 21 an end support element 50 is shown, to be used in combination with the head 40 of Figs. 15-17; also in these figures the same numbers of the previous figures are used, to indicate technically equivalent elements.

In this support 50, in the area no longer occupied by the aforementioned first, second and third ducts, there are small trunks of ducts, indicated with TC, destined to face the ducts 51A-51B, 52A-52B and 53A-53B now carried by the head 40 (see Fig. 17), in order to allow or in any case facilitate the transversal passage of the water between the same ducts and the central chamber 54 of the support 50; these channels TC also open only on the side 50A of the support 50.

In the support 50 of Figs. 18-21, in correspondence with the central chamber 54 there is a dividing screen RD, of the type already mentioned above, made in a single piece with the respective support 50; this realization allows to reduce the number of pieces (support 50 and mesh RD in a single piece), reducing the costs of the part (a single molding cycle and warehouse management of a single piece) and facilitating assembly operations.

In the support 50 according to the proposed variant, each of the two series of passages 55A and 55B according to the embodiment of Figs. 6-7, is replaced by a respective single passage 55 A, 55B of suitable shape and section.

In Figs. 22-25 illustrates an intermediate support element 60, to be used in conjunction with the head 40 of Figs. 15-17 and to the support 50 of Figs. 18-21; also in Figs. 22-25 the same numbers of the previous figures are used to indicate technically equivalent elements.

Also in the support 60 of Figs. 22-25, in correspondence with the central chamber 62 there is a dividing screen RD, made in a single piece with the respective support 60. In the support 60 according to the proposed variant, moreover, each of the two series of passages 61A and 61B is replaced with a single passage 61A, 61B; also the two series of channels 63A and 63B are now replaced by respective single channels, from which the channels 64 A and 64B branch off.

It should be emphasized that, in the variant of Figs. 22-25, the provision of the single channels 63A and 63B is made possible by the fact that the individual channels 64A and 64B of the intermediate support elements 60 have a closed lower portion, which acts as a joining element, in the form of a thin sheet, between the various islands of material which are created between said channels 64A and 64B; the presence of this thin sheet of material constitutes a support for the various membranes C and A, in order to make a suitable seal of the latter on the appropriate lip 56 or 66 of the opposing support element 50 or 60, this lip 56 or 66 creating a continuous seal on the entire perimeter of the opposite side of the membrane C or A.

In this regard, it should be noted that, regardless of the embodiment chosen for the support elements 60, the ratio between width and depth of the individual channels 64A and 64B is preferably less than about 5: 1 (for example, width 1.5 mm and depth 0.3 mm), for example between about 2: 1 and 3: 1 (for example width 1.2-1.3 mm and depth 0.4-0.6 mm).

Fig. 26 shows an example of assembly of a cell 20 including the components of Figs. 15-25.

For the realization of the two types of supports 50 and 60 with mesh RD in a single piece, all the known processes suitable for the purpose can be used, such as for example a molding through an injection of material on several points, and in particular at least one injection perimeter simultaneously with at least one central injection of thermoplastic material; said central injection occurring for example at or near some crossing points or intersections of the filaments or meshes of the mesh RD.

A non-limiting example of realization of the mesh RD provides two series of filaments of substantially semicircular shape, or with an arched profile towards the membrane A or C, opposed to each other and integral in a part, for example flat, which cross in a substantially diagonal direction or inclined with respect to the direction of the trunks of the channel TC of the end supports 50 and / or of the channels 64A and 64B of the intermediate supports 60.

The molding process must in any case be suitable not to leave any burrs or molding residues in the areas near the resting points of the membrane A or C on the mesh RD, in order to avoid possible mechanical damage actions (wear due to rubbing on edges, cuts, etc.) of the membrane itself, in particular when it is subject to the lateral thrusts of the flow of water circulating in the cell. Preferably, although not necessarily, in order to avoid the said risk of damaging the membrane, the section of the filaments of the mesh RD must be rounded or in any case free from accentuated edges in the resting areas; in these areas the injection points of the thermoplastic or rubbery material suitable for making the part are preferably avoided, in order to avoid the presence of irregular surfaces due to the breaking or detachment of the molded part from the "sprue" (part of the scrap hardened in the channels of the mold used to convey the injected material to the various points of the figure) or from the molding nozzle.

The aforementioned arcuate part of the division mesh RD rests on the ion exchange membrane substantially for its tangent part, minimizing the membrane area covered by the network and therefore reducing the membrane area subject to a lack of ion exchange.

It should also be noted that the molding of the RD dividing mesh in a single piece with the support allows for good precision in positioning (centering with respect to the central opening 62 or 54) and in the thicknesses, so that the membrane always has good support in all points, even when it is subject to hydraulic flow.

The dividing mesh RD has substantially a thickness equivalent to the distance between the two lowered seats SR for housing the membrane of the support 60, or a thickness corresponding to the distance between two adjacent membranes or between an adjacent membrane and an electrode.

Preferably, the dividing mesh RD is made of the same elastic material as the support, which prevents any slight dimensional tolerances (e.g. excessive thickness) or residues from the molding process (burrs) from damaging the membrane, which is continuously subject to micro-movements. due to the hydraulic flow (in particular when this flow is deliberately high in order to improve the performance of the device, as in one of the operating configurations considered preferential for the purposes of the invention).

In a further variant, the mesh RD could be of a different material from that of the support 50 or 60 while being integral with the latter, such mesh RD could for example be made separately and then welded to the respective support, or be co-molded with the support by injecting the two materials in different phases of the same molding cycle; in this way it is possible to obtain a single piece that can be easily manipulated during the assembly phase of the device 20.

Fig. 27 shows an exploded view of a possible embodiment of a support 60, according to the variant of Figs. 23-25, co-molded, or over-molded, or in any case integral with an intermediate electrode “+” or "-" indicated here with 70; also in this figure the same numbers of the previous figures are used, to indicate technically equivalent elements.

In the case exemplified in Fig. 27, the intermediate electrode 70 is made of electrically conductive plastic, or other electrically conductive material suitable for the purpose, and could have been previously molded and / or shaped separately and then over-molded with other insulating material, for example of the material of the elastic type (for example silicone or thermoplastic rubbers or similar materials) in order to realize the support 60.

For the sake of simplicity, only the intermediate support 60 comprising the intermediate electrode 70 is described here, considering the respective end support 50 without an intermediate electrode "+" or "-" (the support 50 could in any case be made in the same way as described for the support 60 of Fig. 27, comprising a similar intermediate electrode); as already mentioned above, in this configuration, at least one of the main end electrodes (20B or 20C in Fig. 2) is used, used for descaling, suitably switched electrically, in combination with the intermediate electrodes "+" and "-" to carry out electrochemical self-cleaning.

As can be seen in Fig. 28, the intermediate electrode 70 comprises a first element 71 in the shape of a curved bar, which operates both as an electrical connection element and as a mechanical attachment element with respect to the support 60; a second element 72, also in the shape of a bar, operates mainly as a fixing element of the electrode 70 at the opposite end of the central opening 62 of the support 60.

The bar 71 is provided with a contact ring 73, adapted to receive by interference a respective connecting bar or collector, one of which visible with BC in the following Fig. 29; this BC connection bar is preferably made of metal or in any case provided with a metal core, in order to obtain a low electrical resistance and a good current distribution along the entire length. Furthermore, this bar BC must be rather robust, in order to allow the insertion by interference into a plurality (for example 30) of contact rings 73; the latter are instead preferably made of conductive plastic or rubber, in order to allow themselves to be penetrated with interference, while ensuring subsequent electrical contact, for example of the elastic type. The rings 73 could however also be partly metallic (provided they are isolated from the liquid subject to treatment), for example provided with internal lamellae for radial contact on the bar BC.

The bars 71 and 72 of the electrode 70 are preferably of a lower thickness than the thickness of the support 60 (with reference to the resting part of the membranes, which is the thinnest part), in order to be completely coated or overprinted by the material of the the support itself, consequently making the electrode 70 integral with the support; however, on the bars 71 and 72 there are preferably thin protrusions 74, 75 and 76 which have the same thickness as the corresponding region of the support 60, and serve to keep the bars 71 and 72 centered in the mold during the overmoulding operations. In this case, the bars 71 and 72 are almost completely covered by the electrically insulating material of the support 60, from which only the aforementioned reliefs 74, 75, 76 emerge, which in any case are located in a predetermined area which does not cause problems for operation. of the device 20.

The electrode 71 then comprises a network, which extends between the bars 71 and 72, formed by a diagonal crossing of first filaments 77 and second filaments 78, respectively facing each other and adapted to keep in position a first membrane A or C and a second membrane C or A; in the exemplified case, said filaments 77 and 78 are made of electrically conductive plastic or rubber, forming a single piece with the conductive bars 71 and 72.

In a possible embodiment, the first filaments 77 are made of electrically conductive material (for example carbon fiber) while the second filaments 78 are made of insulating material (for example wire in thermoplastic material), so as to have one side of the mesh electrically insulation and the other side of the electrically conductive mesh. In this way, the electrically conductive material does not create an electrical bridge in the thickness of the network (between the two membranes), short-circuiting the current flow which must instead circulate in the solution to be treated.

In this variant the distribution and / or shape of the filaments could be different from that previously described, in order to connect all the single electrically conductive filaments to each other and / or to the bar 71.

In any case, the filaments 77, 78 are arranged in such a way as to allow the liquid to be treated to flow inside them in a substantially parallel and / or angled direction with respect to the surfaces facing the membranes, or more simply a flow that runs in the its thickness.

Fig. 29 shows an example of assembly of a cell 20 including the components of Figs. 15-21 and 27-28. To this end, it should be noted that the supports 50, 60 and the heads 40 are provided with suitable holes suitable for allowing the total or almost total crossing of the cell by the bars BC, regardless of the position or angle of the supports; the various supports, in correspondence of these holes and of the holes FP, can be provided with respective sealing lips.

In an exemplary configuration, a first bar BC passes through a first support 60 electrically contacting a first ring 73, then passes through a second support 60 (rotated by 90 ° with respect to the first) without making electrical connections, then passes through a third support 60 where it electrically contacts a third ring 73. Still in this exemplary configuration, a second bar BC crosses the first support 60 without making electrical connections, then crosses the second support 60 electrically contacting a second ring 73, then crosses the third support 60 without making electrical connections, and etc.

In this way, the said two bars BC easily realize an alternating electrical connection of electrodes 70 obtaining the said alternation of polarity.

In a further possible variant embodiment, the intermediate electrodes "+" and "-" can be made in the form of a layer on one side of a respective ion exchange membrane A or C. Such intermediate electrodes could for example be made from a fabric in carbon fiber or from a porous sheet of electrically conductive plastic material (for example having a porous structure such as GoreTex®).

In this way, an "electrode / membrane" is therefore provided, formed of a single sheet which on one side has the ion exchange membrane and on the other has the said electrode which, being porous, does not interfere in the circulation of ions through the ion exchange membrane. Obviously, as a further variant, the use of two separate sheets could be envisaged, then assembled together in the purification device 20 to form a structure similar to the one just mentioned.

In Figs. 30, 31, 32 and 33 an exploded view shows a possible embodiment of a support 60, for use in combination with the aforementioned "electrode / membrane".

The support 60 of Figs. 30-33, substantially similar to that of Figs. 21-25, is co-molded, or over-molded, or in any case integral with one or more contact bars 80; in the example provided, each support 60 integrates two bars 80, which in Fig. 32 are shown in exploded view with respect to the support.

The bars 80 substantially have a shape similar to those of the bar 71 of Fig. 28, with relative contact ring 83 and can be made of electrically conductive plastic, or other suitable material; the bars 80 can be printed separately, to then be overprinted with elastic material (for example silicone or thermoplastic rubbers or similar materials) in order to make the supports 60. The bars 80 can also be provided with reliefs, one of which is indicated with 85, having the functions of those previously indicated with 74, 75 and 76 in Fig. 28.

In the case exemplified in Figs. 30-32, the bars 80 are arranged along opposite sides of the central chamber of the support 60, in order to electrically contact the electrodes / membrane.

Fig. 33 shows a cell made using the supports 60 of Figs.

30-32, also in this case indicated with 60 'and 60 "and the aforementioned electrodes / membrane, indicated with EC (those having a part of a cationic membrane) and EA (those having a part of an anionic membrane).

As mentioned, in the non-limiting example of Fig. 30 there are two opposite pairs of contact bars 80, which are then connected together externally to the device 20 at the same polarity, through bars BC; in this way the reliability is improved (double internal contact on the membrane) and / or improved the distribution of electric current flows in electrically conductive plastic materials, which as is known have greater electrical resistance; however, nothing prohibits the use of a single contact bar 80 for each 60 'or 60 "support. For the purposes of manufacturing the device 20, the electrodes / membrane EC and EA are always mounted oriented in the same direction, so as to create an alternation between electrode-membrane (anionic), electrode-membrane (cationic), and so on.

The membrane surface of the electrodes / membrane EC and EA will be mounted to rest and seal on the side 60B of the support provided with the continuous sealing lips 66 along the entire internal perimeter; the electrode surface of the electrodes / membrane EC and EA will instead be mounted to rest on the contact bars 80, on the side 60A of the support provided with the channels 64 A and 64B for the flow of the liquid.

From the above description the characteristics and advantages of the present invention are clear, among which the following should be emphasized:

- the provision of an electrochemical cell or device 20 for purification of liquids integrating characteristics suitable for improving its operating performance and duration, as well as simplifying its construction and reducing its cost; the device can be, if necessary, of small dimensions for easy assembly inside household appliances;

- the provision, in the device 20, of an internal automatic cleaning or washing system, this system being in particular able to produce at least one cleaning substance directly from the liquid subject to the treatment (in the example given, this substance is of the acid type, but in another embodiment it could be of the basic type); the self-cleaning system described comprises a plurality of intermediate electrodes, suitable for producing the substance to be used for the internal washing of the electrochemical device;

- the intermediate electrodes are made of low-cost material and / or directly integrated on the ion exchange membranes of the device, and are easy to connect electrically;

- the possibility of providing a large number of pairs of cationic membranes C and anionic A, in particular to contain the dimensions of the descaling electrodes 20B and 20c (or 47), as well as to contain the dimensions and costs of the entire device;

- the particular sealing configuration on the ion exchange membranes C and A, based on the use of the lips 56, 66 and 67 of the supports 50 and 60, designed to reduce as much as possible the membrane surface used as the sealing edge, which does not come into contact with water and therefore does not participate in ion exchange, although it affects the cost of making the decalcifier (in the case described as an example of the present invention, the unused edge part of membranes A and C on the entire perimeter is only about 5 mm all around);

- the particular sealing configuration on the ion exchange membranes C and A also requires the use of supports provided with a multitude of very narrow channels 64A and 6AB, in order to avoid bending of the ion exchange membranes and the consequent loss of seal on the opposite lips 56, 66;

- the particular configuration of the channels 51A, 51B, 52A, 52B, 53A, 53B, preferably obtained on the heads 40, which allow a total and uniform distribution of the liquid on the end electrode 20B or 20C or 47, even with high flow rates, and thus reducing the risk of deposits;

the use of ducts 51A, 51B, 52A, 52B, 53A, 53B obtained on the heads 40 allows to reduce, if necessary, the risk of a bending of the end supports 50, avoiding a consequent reduction of the relative sections and reduction of the flow rates;

- the standardization and reduction of the number of parts necessary for the realization of the purification device, obtained through a series of the same elements that can be mounted with different angles or directions, to fulfill different purposes (single head and intermediate support elements);

- ease of assembly with automatic systems, by virtue of the aforementioned reduced number of different parts and wide mechanical tolerances of the parts;

- the almost total use of components in molded thermoplastic material, and therefore very economical;

- the overall conformation of the body of the device which, despite being made by means of symmetrical elements, is able to be positioned so that any gases that may have formed can easily flow out.

The invention has been described with reference to its use in the sector of domestic appliances for the purification of water, but it must be understood that it can be applied also in other fields, such as for example the industrial one, for example for the purposes of milk treatment, wine and other beverages and food products, etc., and use in domestic water purification systems, for example to be installed under a sink.

In the case of use in the industrial field, the hydraulic configuration of the device 20 may of course be different from that previously exemplified, and include, for example, more types of ion exchange membranes, for example also using membranes of the bipolar type, interspersed with anionic membranes and cationic, or by providing vents for the gases that are eventually formed in the device during operation.

In a possible variant, for the purposes of manufacturing the device 20, membranes of different types could also be used, for example by alternating divalent cationic membranes with monovalent cationic membranes (which for example do not allow calcium and magnesium to pass, as they are divalent ions).

The configuration of such a device 20 would be substantially similar to those described above with reference to the use of cationic and anionic membranes, creating channels of the concentrate in which the substances accumulate (as they are rejected by the monovalent membrane).

Other possible embodiments of the invention may derive from the combination of at least part of the various systems or components previously described by way of non-limiting example.

Claims (104)

CLAIMS 1. Electrochemical arrangement for purification or treatment of a liquid comprising at least two first electrodes (20B, 20C) between which at least: - an ion exchange divider element of a first type (C; EC) are arranged; - an ion exchange divider of a second type (A; EA); - a plurality of channels (CE, CC, CP) between said first electrodes (20B, 20C), each channel (CE, CC, CP) being at least partially delimited by at least one ion exchange divider element (C, A; EC ,IT'S AT); where in at least one (CP, CE) of said ducts a first part of liquid is susceptible to transit which, in the presence of an electric current flow between said first electrodes (20B, 20C), is destined to release ions in order to be purified and in at least one other (CE, CC) of said ducts a second part of liquid is susceptible to transit which, in the presence of said flow of electric current, is destined to receive ions released by said first part of liquid, characterized by the fact that cleaning means (+, -) are provided for the formation of a cleaning substance or solution, suitable for solubilizing and / or eliminating deposits or encrustations, in particular saline precipitates or bio-films, possibly formed within at least one of these channels (CE, CC, CP). 2. Arrangement, according to claim 1, characterized in that said cleaning means comprise a plurality of second electrodes (+, -), located in correspondence with at least some of said channels (CE, CC, CP). 3. Arrangement according to claim 2, characterized in that said second electrodes (+, -) are electrically connected in pairs with alternating polarity, connected together in parallel, so as to create an alternation of positive and negative polarity. 4. Arrangement according to claim 2 or 3, characterized in that control means are provided, capable of electrically powering said second electrodes (+, -). 5. Arrangement according to claim 4, characterized in that, in the presence of a current flow between said second electrodes (+, -), the latter are operative to form said substance or cleaning solution from the same liquid present in at least some of these channels (CE, CC, CP). 6. Arrangement according to claim 4, characterized in that said control means are capable of electrically supplying said first electrodes (20B, 20C) and said second electrodes (+, -) at different times. 7. Arrangement, according to claim 5, characterized in that means are provided for maintaining the liquid present in at least one of said channels (CE, CC, CP) in static conditions and the liquid present in at least another of said channels ( CE, CC, CP) in dynamic or circulating conditions during the application of the current flow between said second electrodes (+, -). 8. Arrangement according to claim 4, characterized in that said control means are capable of inverting the polarity of said second electrodes (+, -). 9. Arrangement, according to the preceding claim, characterized in that said control means are operative to carry out a first cycle of feeding said second electrodes (+, -) to a first polarity, in order to form said substance or solution of washing in at least one of said channels and a second feeding cycle of said second electrodes (+, -), with polarity opposite to the previous one, in order to form said substance or washing solution in at least another of said channels. 10. Arrangement according to the preceding claim, characterized in that said control means are operative to memorize information relating to at least said first and / or second cycle. 11. Arrangement according to claim 4, characterized in that said control means are programmed to activate a current flow between said second electrodes (+, -) according to measurements carried out by means of sensor means. 12. Arrangement according to the preceding claim, characterized in that said sensor means comprise one or more flow or flow sensors. 13. Arrangement according to claim 11, characterized in that said sensor means comprise at least one electrical absorption meter. 14. Arrangement, according to claim 1, characterized in that at least a first and a second ducting (CE, CC) are provided for said second part of liquid and at least a third ducting (CP) for said first part of liquid, said third channeling (CP) being interposed between a respective first and second channeling (CE, CC). 15. Arrangement, according to the preceding claim, characterized in that: - said third channel (CP) is at least partially delimited by a first type dividing element (C; EC) and a second type dividing element (A; EA), - each of said first and second channels (CE, CC) is at least partially delimited by a first type divider element (C; EC) and a second type divider element (A; EA) or by one of said first electrodes ( 20B, 20C) and one of said dividing elements (C, A; EC, EA). 16. Arrangement, according to claim 14 or 15, characterized in that at least two of said third channels (CP) are provided, between which an intermediate channel (CC) is defined, the latter being at least partially delimited to one side by a first type separator element (C; EC) which delimits one of said third channels (CP) and on the other side by a second type separator element (A; EA) which delimits the other of said third channels (CP) ). 17. Arrangement, according to at least one of the preceding claims, characterized in that circulation or recirculation means (12,22,23,15,21,24) are provided, to realize a substantially closed circuit and / or a continuous circulation of said first part of liquid between accumulation means (P, S) and the respective ducts (CE, CC, CP), until a predetermined purification value of said liquid is reached. 18. Arrangement, according to at least one of the preceding claims, characterized in that first accumulation means (P) of said first part of liquid are provided. 19. Arrangement, according to at least one of the preceding claims, characterized in that second accumulation means (S) for said second part of liquid are provided. 20. Arrangement, according to claim 4, characterized in that said control means are operative to reverse the polarity of said first electrodes (20B, 20C). 21. Arrangement, according to the preceding claim, characterized in that means are provided for reversing the functions of said first accumulation means (P) and of said second accumulation means (S), so that in said first accumulation means (P) said second part of liquid is accumulated and in said second accumulation means (S) said first part of liquid is accumulated, with recirculation in the respective channels (CE, CC, CP). 22. Arrangement, according to at least one of the preceding claims, characterized in that a circulation or recirculation circuit (30A, 30B, 31-34) is provided, for a washing solution or liquid of said first electrodes (20B, 20C) and / or the respective ducts (CE). 23. Arrangement according to the preceding claim, characterized in that the channels (CE) relating to said first electrodes (20B, 20C) are hydraulically connected to each other. 24. Arrangement according to the preceding claim, characterized in that the dividing elements (C, A; EC, EA) which delimit the channels (CE) relating to said first electrodes (20B, 20C) are of the same type. 25. Arrangement according to claim 2, characterized in that said second electrodes (+, -) are made with a material selected from the group comprising synthetic materials made electrically conductive or from the group comprising fibers of conductive material. 26. Arrangement according to claim 2, characterized in that said second electrodes (+, -) are made of a material having an electrical resistance higher than that of the liquid. 27. Arrangement according to claim 1 or 2, characterized in that means are provided for preventing electrical short circuits between two adjacent dividing elements (C, A; EC, EA). 28. Arrangement, according to claim 2, characterized in that said second electrodes (+, -) have an electrical resistance in their thickness higher than that of the liquid. 29. Arrangement according to claim 2, characterized in that said second electrodes (+, -) are made of a material having electrical characteristics suitable for obtaining at least in one direction an electrical resistance higher than that of the liquid. 30. Arrangement according to claim 2, characterized in that said second electrodes (+, -) are substantially mesh-shaped. 31. Arrangement according to claim 2, characterized in that said second electrodes (+, -) have at least partly a porous or permeable structure. 32. Arrangement according to claim 2, characterized in that said second electrodes (+, -) fulfill at least in part the function of spacer for a respective dividing element (C, A; EC, EA). 33. Arrangement according to claim 2, characterized in that said second electrodes (+, -) are at least partly of a composite structure. 34. Arrangement according to claim 2, characterized in that said second electrodes (+, -) are combined with, or part of, a respective dividing element (C, A; EC, EA). 35. Arrangement, according to claim 2, characterized in that said second electrodes (+, -) are integral with, or in any case combined with, a respective support element (50,60; 50 ', 50 ", 60', 60" ) of a dividing element (C, A; EC, EA). 36. Arrangement according to at least one of the preceding claims, characterized in that said intermediate electrodes (+, -) are interconnected and / or connected via at least one respective electrically conductive element (BC), in particular in the form of a common contact bar ( BC). 37. Arrangement, according to claim 1, characterized in that two end bodies (40; 40 ', 40 ") are provided, between which support means (50,60; 50', 50", 60 'are arranged , 60 ") of said dividing elements (C, A; EC, EA) and / or of said second electrodes (+, -). 38. Arrangement according to the preceding claim, characterized in that said end bodies (40) each have a plurality of inlet and outlet fittings (43-46) for the liquid. 39. Arrangement according to the preceding claim, characterized in that said fittings (43-46) comprise at least one inlet (44.46) and one outlet (43.45). 40. Arrangement, according to the preceding claim, characterized in that at least one of said end bodies (40) comprises at least a first inlet (44), a first outlet (43), a second inlet (46) and a second outlet ( 45). 41. Arrangement according to claim 37, characterized in that each end body (40) integrates a respective first electrode (47; 20B, 20C). 42. Arrangement, according to claim 37, characterized in that said support means comprise a plurality of support elements (50,60; 50 ', 50 ", 60', 60"), each of which defines a plurality of respective through openings (54,55A, 55B, 61A, 61B, 63A, 63B) for the transit of the liquid. 43. Arrangement, according to the preceding claim, characterized in that said through openings (54,55A, 55B, 61 A, 61B, 62,63A, 63B) comprise a first opening (54,62), in correspondence with which it is mounted one of said dividing elements (C, A; EC, EA). 44. Arrangement according to claims 42 and 43, characterized in that said through openings (54,55A, 55B, 61A, 61B, 62,63A, 63B) comprise at least a pair of second through openings (55A, 55B, 61 A , 61B). 45. Arrangement according to the preceding claim, characterized in that said through openings (61A, 61B, 62,63A, 63B) comprise at least a pair of third through openings (63A, 63B). 46. Arrangement, according to claims 40 and 45, characterized in that the second through openings (55A, 55B, 61A, 61B, 62,63A, 63B) of a second type support element (60; 60 ', 60 ") are in hydraulic communication both with the third through openings (55A, 55B, 61A, 61B, 62,63A, 63B) of another second type support element (60; 60 ', 60 ") and with said first inlet (44 ) and first exit (43). 47. Arrangement, according to claim 45, characterized in that said third through openings (63A, 63B) are defined in said support elements of the second type (60; 60 ', 60 ") and are in hydraulic communication with the respective first opening (62) of the latter, through small ducts (64A, 64B) in the form of grooves defined on a surface of the second type support element (60; 60 ', 60 "). 48. Arrangement, according to the preceding claim, characterized in that the ratio between the width and the depth of said small ducts (64A, 64B) is less than about 5: 1, and in particular between about 2: 1 and 3: 1. 49. Arrangement, according to claim 37 or 42, characterized in that said support means or elements (50, 60; 50 ', 50 ", 60', 60") comprise at least two support elements of a first type (50 ; 50 ', 50 "), each cooperating with a respective end body (40; 40', 40"). 50. Arrangement, according to the preceding claim, characterized in that said support means (50,60; 50 ', 50', 60 ', 60 ") comprise one or more support elements of a second type (60; 60' , 60 "), each of which cooperates with a respective support element of the first type (50; 50 ', 50") or with another support element of the second type (60; 60', 60 "). 51. Arrangement, according to claim 49, characterized in that at least one of said end body (40; 40 ', 40 ") and support of the first type (50; 50', 50") has one of its surfaces or more channels (51A, 51B, 52A, 52B, 53A, 53B) in the form of grooves. 52. Arrangement, according to the preceding claim, characterized in that said channels comprise one or more first channels (51A, 51B), which branch into respective second channels (52A, 52B), the second channels 52A and 52B branch into further third channels (53A, 53B). 53. Arrangement according to claims 40 and 51 or 52, characterized in that said channels (51A, 51B, 52A, 52B, 53A, 53B) are in hydraulic communication with said second inlet (46) and second outlet (45). 54. Arrangement, according to claims 43 and 51 or 52, characterized in that said channels (51A, 51B, 52A, 52B, 53A, 53B) are defined in said end bodies (40; 40 ', 40 ") and said first type support element (50; 50 ', 50 ") defines grooves (TC) on its surface facing said channels (51A, 51B, 52A, 52B, 53A, 53B), said grooves (TC) leading into said central opening (54). 55. Arrangement, according to claim 43, characterized in that a lowered seat (SR) is defined on at least one surface of said support elements (50, 60; 50 ', 50 ", 60', 60"), which surrounds said first opening (54,62) and houses a portion or edge of a respective dividing element (C, A; EC, EA), the depth of said seat (SR) being in particular equal to about half the thickness of said element divider. 56. Arrangement, according to claim 37, characterized in that at least one first sealing lip (56, 62,67) in contact with a respective dividing element (C, A; EC, EA), said first lip extending in particular around said first opening (54,62). 57. Arrangement, according to claims 55 and 56, characterized in that said first sealing lip (56,62,67) is defined within said seat (SR). 58. Arrangement, according to claims 55 and 56, characterized in that at least said first sealing lip ( 56,62,67) and / or said headquarters (SR). 59. Arrangement, according to claim 37, characterized in that at least one second sealing lip (57A, 57B, 68), within the perimeter of which said openings are defined (54.55A, 55B, 61A, 61B, 62.63A, 63B). 60. Arrangement, according to claim 37, characterized in that at least one third sealing lip (58, 69), within the perimeter of which said second and / or third openings are defined (55A, 55B, 61A, 61B). 61. Arrangement, according to claim 43, characterized in that a respective spacer means (RD) is positioned in correspondence with said first opening (54,62), able to guarantee the presence of a space between two adjacent dividing elements (A, C; EA, EC). 62. Arrangement, according to the preceding claim, characterized in that said spacer means (RD) is substantially in the form of a mesh, comprises two crossed series of filaments of at least partially arched section. 63. Arrangement, according to claim 51, characterized by the fact that in the context of at least one of said channels (51A, 52A, 51B, 52B) one or more supports (PS) are defined. 64. Arrangement according to at least one of the preceding claims, characterized in that said intermediate electrodes (+, -) each comprise at least one contact ring (73) adapted to receive and / or interconnect with a common contact bar (BC). 65. Arrangement according to at least one of the preceding claims, characterized in that said intermediate electrodes (+, -) each comprise at least two bars (80), each arranged along two sides of said first opening (54,62). 66. Arrangement, according to at least one of the preceding claims, characterized in that said second intermediate electrodes (+, -) are integrated in respective support elements (50,60; 50 ', 50 ", 60', 60"), said second electrodes (+, -) having a thickness at least in part less than the thickness of the respective support elements. 67. Arrangement according to claim 30, characterized in that said second electrodes (+, -) comprise first filaments (77) made of electrically conductive material and second filaments (78) made of insulating material. 68. Arrangement according to claim 30 or 67, characterized in that said second electrodes (+, -) comprise filaments of at least partly arcuate or circular cross-section. 69. Arrangement according to claim 2 or 34, characterized in that said intermediate electrodes (+, -) comprise a layer or sheet of electrically conductive material placed on one side of a respective dividing element (A, C; EA, EC ). 70. Arrangement according to the preceding claim, characterized in that the groups (EC, EA) each formed by an intermediate electrode (+, -) and a dividing element (A, C; EA, EC) are oriented in the same direction. 71. Arrangement, according to at least one of the preceding claims, characterized in that said dividing elements are in the form of ion exchange membranes (A, C; EA, EC). 72. Arrangement according to the preceding claim, characterized in that said dividing elements (A, C; EA, EC) are selected in one or more of the following groups or types: anionic membranes and / or cationic membranes and / or bipolar membranes. 73. Arrangement, according to claim 71, characterized in that said dividing elements (A, C; EA, EC) comprise at least pairs or groups of the type: - anionic membranes and cationic, divalent or monovalent membranes, - monovalent cationic membranes and divalent cationic membranes, - monovalent anionic membranes and divalent anionic membranes. 74. Arrangement, according to at least one of the preceding claims, characterized in that means are provided for evacuating said substance or solution from said ducts (CE, CC, CP), together with any deposits or encrustations that have been solubilized by it or removed. 75. Arrangement, according to at least one of the preceding claims, characterized in that means are provided for washing or rinsing said ducts (CE, CC, CP), in order to eliminate said substance or solution and any deposits or encrustations from the latter. have been solubilized or removed. 76. Method of purification or electrochemical treatment of a liquid, of the type based on the use of - at least two electrodes (20B, 20C) between which at least: - an ion exchange divider of a first type (C; EC); - an ion exchange divider of a second type (A; EA); - a plurality of channels (CE, CC, CP) between said first electrodes (20B, 20C), each channel (CE, CC, CP) being at least partially delimited by at least one ion exchange divider element (C, A; EC ,IT'S AT); where in at least one (CP, CE) of said ducts a first part of liquid is made to pass and in at least another (CE, CC) of said ducts a second part of liquid is made to pass, following the presence of a flow of electric current between said first electrodes (20B, 20C), said first part of liquid yielding ions to said second part of liquid, characterized in that the formation of a cleaning substance or solution is provided, suitable for solubilizing and / or eliminating deposits or encrustations possibly formed inside at least one of these channels (CE, CC, CP). 77. Method according to claim 76, characterized in that said substance or solution is formed with liquid present in at least one of said channels (CE, CC, CP). 78. Method according to claim 76 or 77, characterized in that said substance or solution is formed after a step of applying electric current between said first electrodes (20B, 20C). 79. Method according to at least one of the preceding claims, characterized in that said substance or solution is of the acid type. 80. Method according to at least one of the preceding claims, characterized in that said substance or solution is of the basic type. A method according to claim 76 or 77, characterized in that, simultaneously with the formation of said substance or solution, in particular an acid-type solution, the formation of a solution of the opposite type, in particular of the basic type, is provided. 82. Method, according to claim 76 or 77, characterized in that said substance or solution is formed by generating an electric field or an electric voltage or a flow of electric current between pairs of second electrodes with alternating polarity (+, -), said second electrodes (+, -) being placed in correspondence with at least some of said channels (CE, CC, CP). 83. Method according to the preceding claim, characterized in that during the application of electric current between said second electrodes (+, -), the liquid present in at least one of said channels (CE, CC, CP) is kept in static conditions, i.e. in the absence of hydraulic recirculation. 84. Method according to claim 82 or 83, characterized in that during the application of electric current between said second electrodes (+, -), the liquid present in at least one of said channels (CE, CC, CP) is in dynamic conditions, i.e. in the presence of hydraulic recirculation. 85. Method according to claim 76, characterized in that, during the application of electric current between said first electrodes (20B, 20C), the continuous circulation of the liquid present in said ducts (CE, CC, CP) is provided, until a predetermined treatment or purification value of said liquid is reached. 86. Method according to the preceding claim, characterized in that said continuous circulation occurs between liquid accumulation means (P, S, 34) and respective channels (CE, CC, CP). 87. Method, according to claim 76, characterized in that the dosage and accumulation in at least a first container (P) of said first part of liquid is provided. 88. Method according to claim 76, characterized in that the dosage and accumulation in at least a second container (S) of said second part of liquid is provided. 89. Method, according to claim 76, characterized in that the periodic inversion of the polarity of said first electrodes (20B, 20C) is provided. 90. Method, according to claim 76, characterized in that the dosage and accumulation in at least a third container (34) of a third part of liquid is provided. 91. Method, according to claims 87-89, characterized in that the inversion of the functions of at least said first and second containers (P, S), and / or of the respective hydraulic circuit is provided, so that in said first container (P) said second part of liquid is accumulated and recirculated and in said second container (S) said first part of liquid is accumulated and recirculated. 92. Method, according to the previous claim, characterized in that the information relating to the last polarity used for said first electrodes (20B, 20C) is stored. 93. Method according to claim 76, characterized in that a first cleaning cycle with said substance or solution of at least one first channel and a second cleaning cycle with said substance or solution of at least one second channel is provided. 94. Method according to the preceding claim, characterized in that said first and second cleaning cycles are each carried out after a respective cycle of application of electric current between said first electrodes (20B, 20C). 95. Method, according to claim 82, characterized in that the application of electric current between said second electrodes (+, -) is controlled as a function of measurements made by means of sensor means. 96. Method according to claim 76 or 95, characterized in that the flow rate of the liquid passing through one or more ducts (CE, CC, CP) is measured, in particular by means of a flow sensor. 97. Method, according to claim 76 or 95, characterized in that the measurement of electrical absorption is provided during the application of electric current between said first electrodes (20B, 20C). 98. Method, according to at least one of the preceding claims, characterized in that at least one rinsing phase of said ducts (CE, CC, CP) is provided, in particular after a cleaning cycle of the latter carried out with said substance or solution. 99. Method, according to at least one of the preceding claims, characterized in that at least one rinsing phase of said ducts (CE, CC, CP) is provided, to eliminate said substance or cleaning solution from said or said ducts (CE , CC, CP), together with any deposits or encrustations that have been solubilized or removed by it. 100. Domestic apparatus, in particular a washing machine, comprising a purification or treatment arrangement according to one or more of claims 1 to 75. 101. Domestic apparatus, according to the previous claim, characterized by the fact that said arrangement is provided for the softening or descaling of water. 101. Domestic apparatus, according to claim 100 characterized by the fact that said arrangement is provided to purify and / or recover water already used for washing purposes. 102. Domestic apparatus, according to at least one of the preceding claims, characterized in that said arrangement is controlled at least in part by the control system of the apparatus itself. 103. Domestic apparatus, in particular a washing machine, using the purification or treatment method according to one or more of claims 76 to 99, in particular to carry out the purification or softening of water. 104. Arrangement and / or a method of purification or electrochemical treatment of a liquid, according to the teachings of what has been described, claimed and illustrated.