SYSTEM FOR CONTROLLING THE DEGREE OF HARDNESS OF THE WASHING WATER IN A WASHING MACHINE, IN PARTICULAR A DISHWASHER, AND METHOD THEREOF

Abstract

 The present invention relates to a system (1), and a corresponding method, for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, said system (1) comprising:
- a first tank (10) for containing a substance having decalcifying properties, in particular said first tank (10) being equipped with a first inlet (11) for letting water to be decalcified flow into the first tank (10) and a first outlet (12) for letting decalcified water flow out of the first tank (10), to be then supplied into a tub (V) of a washing machine;
- a second tank (20) for containing a regeneration substance, in particular said second tank (20) being equipped with a second inlet (21) for letting water flow into the second tank (20) and a second outlet (22) for letting a regeneration brine, formed upon dissolution of the regeneration substance into the water, flow out of the second tank (20);
- a connection duct (30) that connects the second tank (20) with the first tank (10) for letting the brine formed in the second tank (20) flow towards said first tank (10);
- a supply duct (2) with which a supply valve (3) is associated, which is controlled by a control unit of the washing machine, said supply duct (2) having a first bifurcation (40) into a first branch (41), for supplying the first tank (10), and a second branch (42).
The peculiar feature of the present invention lies in the fact that said second branch (42) comprises a valve (50) located at a second bifurcation (60) into a third branch (43) ending into the tub (V) and a fourth branch (44) ending into the second tank (20), said valve (50) being controlled by said control unit of the washing machine in such a way as to selectively be:
- in a first operating configuration, wherein said valve (50) closes the second branch (42) by interrupting the connection of said second branch (42) with the third branch (43) and with the fourth branch (44), so as to cause the water coming from the supply duct (2) to flow into the first branch (41), into the first tank (10), where the water is decalcified, and then into the tub (V);
- in a second operating configuration, wherein said valve (50) connects the second branch (42) with the third branch (43) to allow the water coming from the supply duct (2) to flow into the tub (V) through said third branch (43);
- in a third operating configuration, wherein said valve (42) connects the second branch (42) with the fourth branch (44) to allow the water coming from the supply duct (2) to flow into the second tank (20) through said fourth branch (44).

Description

[0001] The present invention relates to a system for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, according to the preamble of claim 1. The present invention also relates to an associated method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher.

[0002] As is known, household washing machines utilizing water, in particular dishwashers, are fitted with a washing/rinsing water decalcification system used for reducing the degree of hardness of the water, thus preventing the formation of calcareous deposits inside the washing machine.

[0003] Such a system is also known as decalcifier (or softener), and comprises a resin container containing ion-exchange resins and a tank containing an agent, in particular salt, for regenerating the ion-exchange resins; it should be noted that, in the systems known in the art, the resin container and the salt tank may be separate components or may be integrated into a single container or device.

[0004] The decalcifier exchanges the calcium ions (Ca++) and the magnesium ions (Mg++) in the water entering the wash tub of the washing machine with sodium ions (Na+) contained in suitable resins contained in the resin container.

[0005] The resins, or similar substances, become exhausted after some time of usage, i.e. they run out of sodium ions (Na+) to be exchanged with the calcium ions (Ca++) and magnesium ions (Mg++) in the water; when the resins become exhausted, therefore, the water flowing therethrough will substantially maintain the same hardness as it had at the inlet.

[0006] In order to overcome this problem, a resin regeneration phase is carried out, wherein a suitable regeneration valve permits the introduction of a solution of water and salt (NaCl) into the resin container, such solution being effected by letting a given quantity of water flow into the salt (NaCl) tank, so that it can become saturated with sodium ions (Na+), which will then be released into the resin container in order to regenerate the resins.

[0007] In the systems known in the art, said regeneration valve may consist of:

• a single valve, which opens a passage allowing water to enter the salt container, or
• a diverting valve, which totally or partially diverts the water towards the salt tank for the regeneration function.

[0008] Other problems that may possibly affect the systems for controlling the water hardness used in the washing machines known in the art may come from the fact that the hardness of the mains water may change considerably, in particular it changes depending on the place of installation of the washing machine.

[0009] As a consequence, the washing machines known in the art are equipped with a system that permits maintaining the hardness of the washing water substantially constant within certain limits; in particular, such method envisages the mixing, in the tub of the washing machine, of the water coming from the decalcifier with water directly coming from the mains, i.e. harder water.

[0010] Such mixing, known in the art as "blending", makes it possible to attain a well-defined result as concerns the hardness of the water that is supplied into the wash tub.

[0011] In some washing machines, this blending is effected by providing a calibrated passage (possibly also manually adjustable by the user during the installation of the dishwasher), which diverts part of the water not treated by the decalcifier, in particular by the ion-exchange resins, directly into the tub.

[0012] Although inexpensive, however, the systems using a calibrated, but fixed, passage for performing the blending function suffer from some drawbacks, since such systems cannot be controlled with good precision and cannot ensure the attainment of an optimal result with acceptable continuity.

[0013] As a consequence, in order to be able to attain an optimal result through the blending function, the water hardness control systems employed in the washing machines known in the art preferably make use of a further valve in addition to the regeneration valve; in particular, said further valve is usually located upstream of the resin container, so as to selectively direct the water either into the resin container, in order to abate its degree of hardness, or directly into the tub of the washing machine, in order to perform the blending function.

[0014] The system which, in order to perform the blending function, utilize a further valve in addition to the regeneration valve also suffer from a few drawbacks.

[0015] In particular, such drawbacks are mainly related to the fact that the provision of an additional blending valve necessarily implies a considerable increase in the costs incurred for manufacturing the entire system for controlling the degree of hardness of the washing water.

[0016] In this regard, it should be noted that such cost increase is caused by the need for providing a specific valve for the blending function, by the need for providing specific additional wirings, and by the necessity of providing the control board of the washing machine with a specific output to be connected to the additional valve for the blending function.

[0017] Moreover, the moulds required for making the seat for the additional valve for the blending function are necessarily more complex, and the increase in size inevitably caused by the presence of the additional valve is particularly problematic in light of the fact that the spaces available in modern washing machines have become smaller and smaller.

[0018] In this frame, it is the main object of the present invention to provide a system and a method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, which are so conceived as to overcome the drawbacks of the prior art.

[0019] In particular, it is one object of the present invention to provide a system and a method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, which are so conceived as to be accurately controllable and to ensure the attainment of an optimal result with acceptable continuity.

[0020] It is another object of the present invention to provide a system and a method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, which are so conceived as to not be excessively costly as far as production and implementation are concerned.

[0021] It is a further object of the present invention to provide a system for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, which, in order to perform the various functions of said system and method, does not require different wirings and/or modifications to the construction of the control board of the washing machine.

[0022] It is yet another object of the present invention to provide a system for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, which is so realized that it is not too bulky and can be easily housed in the spaces available in the receiving washing machine.

[0023] Said objects are achieved by the present invention through a system and a method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, incorporating the features set out in the appended claims, which are an integral part of the present description.

[0024] Further objects, features and advantages of the present invention will become apparent from the following detailed description and from the annexed drawings, which are supplied by way of non-limiting explanatory example, wherein:

• Figure 1 shows a schematic view of a system for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, according to the present invention;
• Figures 2a and 2b show first and second embodiments, respectively, of a component of the system according to the present invention;
• Figure 3a depicts the component shown in Figure 2a in a first operating configuration, while Figure 3b shows a schematic view representative of the operation of the system according to the present invention when said component is in said first operating configuration;
• Figure 4a depicts the component shown in Figure 2a in a second operating configuration, while Figure 4b shows a schematic view representative of the operation of the system according to the present invention when the component is in said second operating configuration;
• Figure 5a depicts the component shown in Figure 2a in a third operating configuration, while Figure 5b shows a schematic view representative of the operation of the system according to the present invention when the component is in said third operating configuration.

[0025] With reference to the annexed drawings, in Figure 1 reference numeral 1 designates as a whole a preferred embodiment of a system for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, according to the present invention.

[0026] Reference numeral 10 designates a first tank for containing a substance (normally called "resin") having decalcifying properties, in particular said first tank 10 being equipped with a first inlet 11 for letting water to be decalcified flow into the first tank 10 and a first outlet 12 for letting decalcified water flow out of the first tank 10, to be then supplied into a tub V of a washing machine.

[0027] It should be noted that in the annexed drawings the washing machine is not shown in its entirety; in fact, they only show the tub V of said washing machine. The system 1 comprises a second tank 20 for containing a regeneration substance (said regeneration substance normally consisting of salt), in particular said second tank 20 being equipped with a second inlet 21 for letting water flow into the second tank 20 and a second outlet 22 for letting a regeneration brine, formed upon dissolution of the regeneration substance into the water, flow out of the second tank 20.

[0028] It should be noted that the first tank 10 and the second tank 20 are included in a softener device, designated as a whole by reference "D" in the annexed drawings; it is however clear that the first tank 10 and the second tank 20 may also be realized as separate components not belonging to a softener device D.

[0029] The system 1 comprises also a connection duct 30 that connects the second tank 20 with the first tank 10 for letting the brine formed in the second tank 20 flow towards said first tank 10. Preferably, said connection duct 30 comprises a non-return valve 31 adapted to allow the brine to flow from the second tank 20 towards the first tank 10 while preventing a liquid (which may be either water to be decalcified and/or decalcified water) from flowing towards said second tank 20.

[0030] The system 1 according to the present invention further comprises a supply duct 2 with which a supply valve 3 is associated, which is controlled by a control unit (not shown in the annexed drawings) of the washing machine, said supply duct 2 showing a first bifurcation 40 into a first branch 41, for supplying the first tank 10, and a second branch 42.

[0031] In a preferred embodiment, said first branch 41 ends into the connection duct 30, in particular downstream of said non-return valve 31; it is however clear that said first branch 41 may also be realized to end into the first inlet 11 leading into the first tank 10, or to end into a inlet (not shown in the annexed drawings) of the first tank 10 specially provided for such purpose.

[0032] Preferably, the system 1 comprises a volumetric meter 4 associated with the supply duct 2, in particular said meter 4 being located upstream of said first bifurcation 40 of the supply duct 2.

[0033] It must be pointed out that, in the present description, the terms "upstream" and "downstream" are used with reference to the path followed by the water, starting from the supply duct 2, in order to reach the tub V of the washing machine.

[0034] Preferably, said meter 4 is of the turbine type and comprises an impeller fitted with a magnet enclosed in a housing and an element which senses the magnetic field generated by the magnet. For example, said sensing element may be a reed contact, comprising reeds enclosed in a glass housing filled with inert gas, or a Hall-effect sensor.

[0035] Preferably, the turbine or impeller of the volumetric meter 4 is positioned inside the supply duct 2, while the sensing element is positioned outside said supply duct 2; furthermore, the meter 4 may be integrated with one of the components of the system 1 according to the present invention.

[0036] The magnet of the meter 4 generates a number of signals corresponding to the number of impeller revolutions; said signals are detected by the sensing element and sent to a control device (not shown in the annexed drawings), in particular of the electronic type, of the system 1 of the present invention.

[0037] In a preferred embodiment, said first bifurcation 40 consists of a multifunction device.

[0038] It should be noted that said multifunction device is preferably so realized as to comprise an air gap 5; as is known, the air gap 5 acts as a device for preventing water from flowing back into the mains. Moreover, said multifunction device may perform several other functions, e.g. additional functions like venting into the outside environment and as an outlet column for vapours coming from the tub V of the washing machine.

[0039] In accordance with this preferred embodiment, wherein the first bifurcation 40 consists of a multifunction device, said multifunction device preferably comprises a first container 40A in fluidic communication with the first branch 41 and a second container 40B in fluidic communication with the second branch 42; in particular, the first container 40A and the second container 40B are at least partially separated by a wall 40C so realized as to allow the water in the second container 40B to overflow into the first container 40A (as shown in Fig. 3b).

[0040] It is evident that, in accordance with the teachings of the present invention, the first bifurcation 40 may also be realized otherwise, e.g. said first bifurcation 40 may be provided as a ramification of the supply duct 2, in particular said ramification being located downstream of an air gap 5 associated with the supply duct 2; it is also evident that in such an embodiment, the air gap 5 will be realized independently and directly on the supply duct 2.

[0041] In accordance with the present invention, the second branch 42 of the system 1 comprises a valve (designated as a whole by reference numeral 50 in the annexed drawings), positioned at a second bifurcation 60 into a third branch 43 ending into the tub V and a fourth branch 44 ending into the second tank 20, in particular into the second inlet 21 for letting water flow into said second tank 20, said valve 50 being controlled by said control unit of the washing machine in such a way as to selectively be:

• in a first operating configuration (which may be defined as "closed" or "decalcification" configuration, said first operating condition being shown in Figures 2a, 3a and 3b), wherein said valve 50 closes the second branch 42 by interrupting the connection of said second branch 42 with the third branch 43 and with the fourth branch 44, so as to cause the water coming from the supply duct 2 to flow into the first branch 41, into the first tank 10, where the water is decalcified (since the first tank 10 contains a substance having decalcifying properties), and then into the tub V;
• in a second operating configuration (which may also be defined as "blending" configuration, said second operating condition being shown in Figures 4a and 4b), wherein said valve 50 connects the second branch 42 with the third branch 43 to allow the water coming from the supply duct 2 to flow into the tub V through said third branch 43;
• in a third operating configuration (which may also be defined as "regeneration" configuration, said third operating condition being shown in Figures 2b, 5a and 5b), wherein it connects the second branch 42 with the fourth branch 44 to allow the water coming from the supply duct 2 to flow into the second tank 20 through said fourth branch 44.

[0042] It is clear that said control unit controls, in addition to the supply valve 3 and the valve 50, also other components of the washing machine, such as, for example, the meter 4.

[0043] As can be seen in the annexed drawings, the fourth branch 44 preferably ends into the second inlet 21 for letting water flow into said second tank 20.

[0044] Furthermore, the valve 50 according to the present invention comprises:

• a first movable assembly (designated as a whole by reference numeral 51) equipped with a first core 51A and a first obstructor 51B for closing/opening a first passage 51C that puts the second branch 42 in communication with the third branch 43, said first movable assembly 51 being associated with a first thrust element 51D adapted to exert a thrust on the first movable assembly 51 to keep the first obstructor 51B in a position where it closes the first passage 51C;
• a second movable assembly (designated as a whole by reference numeral 52) equipped with a second core 52A and a second obstructor 52B for closing/opening a second passage 52C that puts the second branch 42 in communication with the fourth branch 44, said first movable assembly 51 being associated with a second thrust element 52D adapted to exert a thrust on the second movable assembly 52 to keep the second obstructor 52B in a position where it closes the second passage 52C,

wherein said first core 51A and second core 52A are activated by a common coil 53, and wherein the excitation of said common coil 53 is such as to activate the first movable assembly 51 and the second movable assembly 52 in a differentiated manner.

[0045] In this regard, it should be noted that the first core 51A and the second core 52A are made of ferromagnetic material, suitable for being attracted by the coil 53 when the latter is energized.

[0046] In accordance with a preferred embodiment, the first thrust element 51D has less preload than the second thrust element 52D. It must be pointed out that each one of said first and second thrust elements 51D, 52D is implemented as an elastic element, in particular a coil spring or an equivalent element.

[0047] Furthermore, the first passage 51C has bigger dimensions than the second passage 52C, in particular in terms of width of the respective cross-sections.

[0048] In addition, the valve 50 comprises an insert 54, in particular made of non-ferromagnetic material, positioned between the first core 51A and the second core 52A; said insert 54 makes it possible to appropriately separate such components, especially in order to prevent any mutual dragging of the first core 51A and second core 52A following the activation of the common coil 53.

[0049] Still in accordance with a preferred embodiment, the second bifurcation 60 of the system 1 according to the present invention is realized by a ramification 50A, 50B formed in the body of the valve 50 and/or associated with said body of the valve 50.

[0050] In particular, and in accordance with a first embodiment (shown in Fig. 2a), said ramification comprises at least one duct 50A external to the body of the valve 50, wherein said at least one duct 50A allows the second branch 42 to be put in fluidic communication with the first passage 51C and with the second passage 52C; as can be seen in Fig. 2a, which shows a sectional side view of the valve 50, said at least one duct 50A is substantially C-shaped, since it has two substantially parallel tracts joined by a tract substantially perpendicular to the other two tracts.

[0051] In accordance with a second embodiment (shown in Fig. 2b), said ramification comprises a gap 50B, in particular having a substantially annular shape, formed externally to the first core 51A and the second core 52A, wherein said gap 50B allows a first chamber 50C, in which the first passage 51C is located, to be put in fluidic communication with a second chamber 50D, in which the second passage 52C is located.

[0052] It is clear from the above description that, in said first ("closed" or "decalcification") operating configuration (see, in particular, Figures 3a and 3b), the coil 53 is kept inactive (i.e. non-energized) and the first obstructor 51B is kept in a position where it closes the first passage 51C through the thrust exerted by the first thrust element 51D, while at the same time the second obstructor 52B is kept in a position where it closes the first passage 51C through the thrust exerted by the first thrust element 51D. As a result, in this first operating configuration the interruption of the connection of the second branch 42 with both the third branch 43 and the fourth branch 44 is effected without having to excite the common coil 53.

[0053] It is also clear that, in this first operating configuration of the valve 50 and in a condition wherein the supply valve 3 is open, the flow of water coming from the supply duct 2 and from the first bifurcation 40 is stopped in the second branch 42 because of the particular operating configuration of said valve 50; as a consequence, the water coming from the supply duct 2 arrives at the first bifurcation 40 and is directed directly (i.e. without flowing through the second tank 30) into the first branch 41, into the first tank 10 (where it is decalcified), and then into the tub V.

[0054] In particular, when the first bifurcation 40 consists of a multifunction device comprising a first container 40A in fluidic communication with the first branch 41 and a second container 40B in fluidic communication with the second branch 42 (as previously described), the water coming from the supply duct 2 enters the second container 40B, fills it up to the top of the wall 40C, and then overflows (see also the arrow in Fig. 3b) into the first container 40A, to flow then into the first branch 41, into the first tank 10, and into the tub V. This path followed by the water during the decalcification phase is shown by bold lines in Fig. 3b.

[0055] In accordance with the present invention, in order to effect the switching from the first to the second (blending) operating condition (see Figures 4a and 4b), the coil 53 is excited (in particular, under control of the control unit of the washing machine), so as to overcome the thrust exerted by the first thrust element 51D, which is preloaded less than the second thrust element 52D; as a result, the first obstructor 51B is moved in a position where it opens the first passage 51C to allow the water to flow into the third branch 43, while the second obstructor 52B is kept in a position where it closes the second passage 52C under the thrust exerted by the second thrust element 52D.

[0056] In particular, said switching from the first to the second operating condition is effected by exciting the valve 50 with the supply valve 3 closed (in particular, such operations are always carried out under control of the control unit of the washing machine); because the first obstructor assembly 51 has less preload than the second obstructor assembly 52, the first obstructor 51B is attracted and thus opens the first passage 51C to allow the non-decalcified water to flow directly into the tub V through the third branch 43. The path followed by the water during the blending phase is shown by bold lines in Fig. 4b.

[0057] When the first obstructor assembly 51 is positioned in such a way as to keep the first passage 51C open, the control unit of the washing machine can control the opening of the supply valve 3 in order to introduce directly into the tub V the desired quantity of non-decalcified water; in particular, such desired quantity of water may be sensed by the meter 4 and communicated to the control unit of the washing machine.

[0058] In accordance with the present invention, in order to effect the switching into the third operating (regeneration) condition (see Figures 5a and 5b), the coil 53 is excited (still under control of the control unit of the washing machine), so as to overcome the thrust exerted by the second thrust element 52D, which is preloaded more than the first thrust element 51D; as a result, the second obstructor 52B is moved into a position where it opens the second passage 52C to allow the water to flow into the fourth branch 44, while the first obstructor 51B is kept in a position where it closes the first passage 51C under the thrust exerted by the first thrust element 51D.

[0059] In particular, said switching into the third operating condition is effected by exciting the valve 50 with the supply valve 3 open; because the second obstructor assembly 52 has more preload than the first obstructor assembly 51, the second obstructor 52B is attracted and thus opens the second passage 52C to allow the water to flow into the second tank 20 through said fourth branch 44 and then into the first tank 10 to effect the regeneration of the substances with decalcifying properties contained in said first tank 10.

[0060] The path followed by the water during the regeneration phase is shown by bold lines in Fig. 5b.

[0061] It is therefore clear that the system 1 for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, according to the present invention permits overcoming the drawbacks suffered by the prior art, in that the system 1 is so conceived as to ensure the attainment of an optimal result from the different decalcification, regeneration and blending functions with acceptable continuity, while at the same time not implying any additional cost for realizing and implementing such different functions.

[0062] In this respect, it must be pointed out that the system 1 according to the present invention envisages the use of just one valve 50, which makes it possible to perform all the decalcification, blending and regeneration functions while at the same time ensuring that such functions will be executed with precision and will provide constant results repeatable an indefinite number of times.

[0063] It is therefore evident that the use of a single valve 50 avoids the need for making different wirings and/or modifications to the construction of the control board of the washing machine in order to implement said different decalcification, blending and regeneration functions.

[0064] Moreover, the fact the a single valve 50 is used, which is so realized as to be able to perform all those functions which in the prior art could only be effected through the use of two different valves, makes it possible to reduce the space necessary for housing the entire system 1 within a washing machine.

[0065] The following will describe the main phases of a method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, in accordance with the present invention, wherein said washing machine comprises a system 1 comprising:

• a first tank 10 for containing a substance having decalcifying properties, in particular said first tank 10 being equipped with a first inlet 11 for letting water to be decalcified flow into the first tank 10 and a first outlet 12 for letting decalcified water flow out of the first tank 10, to be then supplied into a tub V of a washing machine;
• a second tank 20 for containing a regeneration substance, in particular said second tank 20 being equipped with a second inlet 21 for letting water flow into the second tank 20 and a second outlet 22 for letting a regeneration brine, formed upon dissolution of the regeneration substance into the water, flow out of the second tank 20;
• a connection duct 30 that connects the second tank 20 with the first tank 10 for letting the brine formed in the second tank 20 flow towards said first tank 20;
• a supply duct 2 with which a supply valve 3 is associated, which is controlled by a control unit of the washing machine, said supply duct 2 having a first bifurcation 40 into a first branch 41, for supplying the first tank 10, and a second branch 42.

[0066] The method according to the present invention comprises the step of modifying the operating configuration of a valve 50 located at a second bifurcation 60 into a third branch 43 ending into the tub V and a fourth branch 44 ending into the second tank, in particular into the second inlet 21 for letting water flow into said second tank 20, said step of modifying the operating configuration being carried out under control of said control unit of the washing machine through the following steps:

a) configuring said valve 50 so that it is in a first operating configuration ("closed" or "decalcification" configuration, shown in Figures 2a, 3a and 3b) for closing the second branch 42 by interrupting the connection of said second branch 42 with the third branch 43 and with the fourth branch 44, so as to cause the water coming from the supply duct 2 to flow into the first branch 41, into the first tank 10, and then into the tub V;

b) actuating said valve 50 in order to switch it into a second operating configuration ("blending" configuration, shown in Figures 4a and 4b), wherein said valve 50 connects the second branch 42 with the third branch 43 to allow the water coming from the supply duct 2 to flow into the tub V through said third branch 43;

c) actuating said valve 50 in order to switch it into a third operating configuration (which may also be defined as "regeneration" configuration, said third operating condition being shown in Figures 2b, 5a and 5b), wherein it connects the second branch 42 with the fourth branch 44 to allow the water coming from the supply duct 2 to flow into the second tank 20 through said fourth branch 44.

[0067] According to the method of the present invention, said step a) is carried out through a step a1) of keeping a coil 53 of the valve 50 inactive, said coil 53 being common to a first core 51A of a first movable assembly 51, equipped with a first obstructor 51B for closing/opening a first passage 51C that puts the second branch 42 in communication with the third branch 43, and to a second core 52A of a second movable assembly 52, equipped with a second obstructor 52B for closing/opening a second passage 52C that puts the second branch 42 in communication with the fourth branch 44.

[0068] According to the method of the present invention, said step b) is carried out through a step b1) of exciting said coil 53 so as to overcome the thrust exerted by a first thrust element 51D associated with the first movable assembly 51 and obtain the opening of the first passage 51C, in particular said first thrust element 51D being preloaded less than a second thrust element 52D associated with the second movable assembly 52.

[0069] In accordance with the present invention, said step b1) is carried out jointly with a step b2) of keeping the supply valve 3 in the closed position. As previously explained, since the first obstructor assembly 51 is so realized as to have less preload than the second obstructor assembly 52, the first obstructor 51B is attracted and thus opens the first passage 51C to allow the non-decalcified water to flow directly into the tub V through the third branch 43.

[0070] Said steps b1) and b2) may then be followed by a step b3) of opening the supply valve 3, so as to introduce directly into the tub V the desired quantity of non-decalcified water; in particular, said desired quantity of water may be detected by the meter 4.

[0071] According to the method of the present invention, said step c) is carried out through a step c1) of exciting said coil 53 so as to overcome the thrust exerted by a second thrust element 52D associated with the second movable assembly 52 and obtain the opening of the second passage 52C, in particular said second thrust element 52D being preloaded more than the first thrust element 51D associated with the first movable assembly 51.

[0072] In particular, said step c1) may be carried out simultaneously with or after a step c-1) of opening the supply valve 3.

[0073] The features of the system 1 and of the method according to the present invention, as well as the advantages thereof, are apparent from the above description.

[0074] In fact, the system 1 and the method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, according to the present invention permit achieving optimal results when performing the different decalcification, blending and regeneration functions, in particular said different functions being performed with acceptable continuity without implying any additional cost for their realization and implementation.

[0075] In this regard, the peculiar features and operating modes of the valve 50 included in the system 1 make it possible to use a single valve 50 for performing all the decalcification, blending and regeneration functions, while at the same time ensuring an accurate execution of such phases with constant results repeatable an indefinite number of times.

[0076] It is therefore evident that the use of a single valve 50 avoids the need for making different wirings and/or modifications to the construction of the control board of the washing machine in order to implement said different decalcification, blending and regeneration functions.

[0077] Moreover, the fact that a single valve 50 is used, which is so realized as to be able to perform all those functions which in the prior art could only be effected through the use of at least two different valves, makes it possible to reduce the space necessary for housing the entire system 1 within a washing machine.

[0078] The system 1 for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, and the associated method described herein by way of example may be subject to many possible variations without departing from the novelty spirit of the inventive idea; it is also clear that in the practical implementation of the invention the illustrated details may have different shapes or be replaced with other technically equivalent elements.

Claims

1. System (1) for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, said system (1) comprising:

- a first tank (10) for containing a substance having decalcifying properties, in particular said first tank (10) being equipped with a first inlet (11) for letting water to be decalcified flow into the first tank (10) and a first outlet (12) for letting decalcified water flow out of the first tank (10), to be then supplied into a tub (V) of a washing machine;

- a second tank (20) for containing a regeneration substance, in particular said second tank (20) being equipped with a second inlet (21) for letting water flow into the second tank (20) and a second outlet (22) for letting a regeneration brine, formed upon dissolution of the regeneration substance into the water, flow out of the second tank (20);

- a connection duct (30) that connects the second tank (20) with the first tank (10) for letting the brine formed in the second tank (20) flow towards said first tank (20);

- a supply duct (2) with which a supply valve (3) is associated, which is controlled by a control unit of the washing machine, said supply duct (2) having a first bifurcation (40) into a first branch (41), for supplying the first tank (10), and a second branch (42),

said system (1) being characterized in that
the second branch (42) comprises a valve (50) located at a second bifurcation (60) into a third branch (43) ending into the tub (V) and a fourth branch (44) ending into the second tank (20), said valve (50) being controlled by said control unit of the washing machine in such a way as to selectively be:

- in a first operating configuration, wherein said valve (50) closes the second branch (42) by interrupting the connection of said second branch (42) with the third branch (43) and with the fourth branch (43), so as to cause the water coming from the supply duct (2) to flow into the first branch (41), into the first tank (10), where the water is decalcified, and then into the tub (V);

- in a second operating configuration, wherein said valve (50) connects the second branch (42) with the third branch (43) to allow the water coming from the supply duct (2) to flow into the tub (V) through said third branch (43);

- in a third operating configuration, wherein said valve (42) connects the second branch (42) with the fourth branch (44) to allow the water coming from the supply duct (2) to flow into the second tank (20) through said fourth branch (44).

2. System (1) according to claim 1, characterized in that said valve (50) comprises:

- a first movable assembly (51) equipped with a first core (51A) and a first obstructor (51B) for closing/opening a first passage (51C) that puts the second branch (42) in communication with the third branch (43), said first movable assembly (51) being associated with a first thrust element (51D) adapted to exert a thrust on the first movable assembly (51) to keep the first obstructor (51B) in a position where it closes the first passage (51C);

- a second movable assembly (52) equipped with a second core (52A) and a second obstructor (52B) for closing/ opening a second passage (52C) that puts the second branch (42) in communication with the fourth branch (44), said first movable assembly (51) being associated with a second thrust element (52D) adapted to exert a thrust on the second movable assembly (52) to keep the second obstructor (52B) in a position where it closes the second passage (52C),

wherein said first core (51A) and second core (52A) are activated by a common coil (53), and wherein the excitation of said common coil (53) is such as to activate the first movable assembly (51) and the second movable assembly (52) in a differentiated manner.

3. System (1) according to claim 2, characterized in that the first thrust element (51D) has less preload than the second thrust element (52D).

4. System (1) according to one or more of the preceding claims 2 and 3, characterized in that the first passage (51C) has bigger dimensions than the second passage (52C), in particular in terms of width of the respective cross-sections.

5. System (1) according to one or more of the preceding claims 2 to 4, characterized in that said valve (50) comprises an insert (54), in particular made of non-ferromagnetic material, positioned between the first core (51A) and the second core (52A).

6. System (1) according to one or more of the preceding claims, characterized in that the second bifurcation (60) is realized by a ramification (50A, 50B) formed in the body of the valve (50) and/or associated with said body of the valve (50).

7. System (1) according to claim 6, characterized in that said ramification comprises at least one duct (50A) external to the body of the valve (50), wherein said at least one duct (50A) allows the second branch (42) to be put in fluidic communication with the first passage (51C) and with the second passage (52C).

8. System (1) according to claim 6, characterized in that said ramification comprises a gap (50B), in particular having a substantially annular shape, formed externally to the first core (51A) and the second core (52A), wherein said gap (50B) allows a first chamber (50C), in which the first passage (51C) is located, to be put in fluidic communication with a second chamber (50D), in which the second passage (52C) is located.

9. System (1) according to one or more of the preceding claims, characterized in that said first bifurcation (40) consists of a multifunction device, in particular comprising a first container (40A) in fluidic communication with the first branch (41) and a second container (40B) in fluidic communication with the second branch (42).

10. Method for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, wherein said washing machine comprises a system (1) comprising:

- a first tank (10) for containing a substance having decalcifying properties, in particular said first tank (10) being equipped with a first inlet (11) for letting water to be decalcified flow into the first tank (10) and a first outlet (12) for letting decalcified water flow out of the first tank (10), to be then supplied into a tub (V) of a washing machine;

- a second tank (20) for containing a regeneration substance, in particular said second tank (20) being equipped with a second inlet (21) for letting water flow into the second tank (20) and a second outlet (22) for letting a regeneration brine, formed upon dissolution of the regeneration substance into the water, flow out of the second tank (20);

- a connection duct (30) that connects the second tank (20) with the first tank (10) for letting the brine formed in the second tank (20) flow towards said first tank (20);

- a supply duct (2) with which a supply valve (3) is associated, which is controlled by a control unit of the washing machine, said supply duct (2) having a first bifurcation (40) into a first branch (41), for supplying the first tank (10), and a second branch (42),

said method being characterized in that it comprises the step of modifying the operating configuration of a valve (50) located at a second bifurcation (60) into a third branch (43) ending into the tub (V) and a fourth branch (44) ending into the second tank (20), in particular into the second inlet (21) for letting water flow into said second tank (20), said step of modifying the operating configuration being carried out under control of said control unit of the washing machine through the following steps:

a) configuring said valve (50) so that it is in a first operating configuration for closing the second branch (42) by interrupting the connection of said second branch (42) with the third branch (43) and with the fourth branch (44), so as to cause the water coming from the supply duct (2) to flow into the first branch (41), into the first tank (10), and then into the tub (V);

b) actuating said valve (50) in order to switch it into a second operating configuration, wherein said valve (50) connects the second branch (42) with the third branch (43) to allow the water coming from the supply duct (2) to flow into the tub (V) through said third branch (43);

c) actuating said valve (50) in order to switch it into a third operating configuration, wherein it connects the second branch (42) with the fourth branch (44) to allow the water coming from the supply duct (2) to flow into the second tank (20) through said fourth branch (44).

11. Method according to claim 10, characterized in that said step a) is carried out through a step a1) of keeping a coil (53) of the valve (50) inactive, said coil (53) being common to a first core (51A) of a first movable assembly (51), equipped with a first obstructor (51B) for closing/opening a first passage (51C) that puts the second branch (42) in communication with the third branch (43), and to a second core (52A) of a second movable assembly (52), equipped with a second obstructor (52B) for closing/opening a second passage (52C) that puts the second branch (42) in communication with the fourth branch (44).

12. Method according to one or more of claims 10 and 11, characterized in that said step b) is carried out through a step b1) of exciting said coil (53) so as to overcome the thrust exerted by a first thrust element (51D) associated with the first movable assembly (51) and obtain the opening of the first passage (51C), in particular said first thrust element (51D) being preloaded less than a second thrust element (52D) associated with the second movable assembly (52).

13. Method according to one or more of claims 10 to 12, characterized in that said step b1) is carried out jointly with a step b2) of keeping the supply valve (3) in the closed position.

14. Method according to one or more of claims 10 to 13, characterized in that said step c) is carried out through a step c1) of exciting said coil (53) so as to overcome the thrust exerted by a second thrust element (52D) associated with the second movable assembly (52) and obtain the opening the second passage (52C), in particular said second thrust element (52D) being preloaded more than the first thrust element (51D) associated with the first movable assembly (51).

15. Method according to claim 14, characterized in that said step c1) is carried out simultaneously with or after a step c-1) of opening the supply valve (3).

16. Valve (50) adapted to be associated with a system (1) for controlling the degree of hardness of the washing water in a washing machine, in particular a dishwasher, according to one or more of the preceding claims 1 to 9.

17. Washing machine comprising a system (1) according to one or more of the preceding claims 1 to 9.

Drawing