ANTI-CONTAMINATION SAFETY SYSTEM OF WATER SUPPLY NETWORK FOR A WATER TREATMENT SYSTEM OF A DISHWASHING MACHINE, RELATED WATER TREATMENT SYSTEM AND DISHWASHING MACHINE

Abstract

 Water treatment system (2) for a dishwashing machine (1). The system comprises a safety system (3), in turn comprising means (30) adapted to prevent contamination and/or pollution from wash liquid of a tank (6) adapted to contain salts, comprised in the water treatment system (2). The safety system (3) is adapted to communicate with a control unit of the dishwashing machine (1) in order to signal at least a potential risk of contamination and/or pollution of said tank (6).

Description

[0001] The present invention relates to an anti-contamination safety system adapted to be used in a water treatment system of a dishwashing machine, adapted to prevent contamination of the water supply network, in particular of a tank, e.g. the salt tank comprised in the same water treatment system.

[0002] The present invention also relates to a water treatment system of a dishwashing machine, adapted to prevent contamination of the water supply network, and in particular of a tank, e.g. the salt tank.

[0003] The present invention further relates to a dishwashing machine comprising systems adapted to prevent contamination of the water supply network, and in particular of a tank, e.g. the salt tank, comprised in a water treatment system.

[0004] It is known that dishwashing machines comprise a water treatment system in which a salt tank comprises a filler neck, equipped with a cap, through which salts can be put into said tank. It is known that the salt tank cap is provided with means ensuring the hydraulic sealing of the tank in order to prevent the liquid in a wash chamber of a dishwashing machine from coming in contact with the liquid in the salt tank. It is known that the cap for putting salts into the salt tank is provided with hydraulic sealing means in order to prevent the salt water, called brine or regeneration fluid, from leaking out of the salt tank and reaching the wash chamber, thus getting in contact with the walls of the wash chamber, during the washing phase of the dishwashing machine, thereby causing problems of rust on the walls of the wash chamber.

[0005] Safety regulations are known as regards pollution of the water mains or water supply network, e.g. the EN 61770 regulation. Such regulations set manufacturing specifications to avoid contamination and/or pollution caused by a possible pressure drop in the water mains. A pressure drop may, in fact, cause the suction of harmful products used for dishwashing, such as, for example, detergent and/or rinse aid.

[0006] The manufacturing specifications dictated by the regulations are classified according to the type of fluid from which contamination and/or pollution must be avoided, and in particular prevented. For example, the EN 61770 regulation specifies that drinking water is classified as a Category 1 liquid. Salt water, e.g. brine for epoxy resin regeneration, is classified as a Category 2 liquid. Rinse water is classified as a Category 3 liquid, while wash water, which contains detergent, is classified as a Category 5 liquid. The higher the classification category, the higher the technical specifications that the dishwashing machine must comply with in order to prevent that liquid from polluting the water network. For example, the regulation requires that, as a measure against detergent pollution, there must be a hydraulic separation of the circuit by at least 20 mm. Furthermore, the regulation specifies that the pressure downstream of a circuit must match the atmospheric pressure, so as to prevent the downstream fluid from returning in contact with the upstream fluid.

[0007] As regards the manufacturing specifications concerning pollution caused by the salt necessary for the resin regeneration fluid of the water treatment system, the regulation gives the possibility of using a pair of non-return valves, since the risk of pollution is lower because the product is less harmful.

[0008] Dishwashing machines compliant with the current regulations are known which comprise a first safety system, less effective against contamination, adapted to protect the water treatment system, in particular using water not for human use, and a second safety system, more effective, adapted to prevent contamination of the water supply system from the product used for dishwashing, in particular detergent. At present, this dishwasher design solution only permits avoiding some types of possible contamination and/or pollution.

[0009] In fact, one possible operating condition of the dishwashing machine has been found to allow for contamination of the water treatment system. In particular, since in dishwashers the salt tank cap is located inside the wash chamber, in the event that the user positions the cap incorrectly, i.e. if tightness is not ensured, or, in the worst of cases, if the cap is not installed at all, then the salt tank may be contaminated and/or polluted by wash and/or rinse water, and the currently implemented anti-pollution safety measures will not suffice.

[0010] So far, regulations have not yet taken into account this possibility of severe pollution and/or contamination.

[0011] One possible solution to the problem may be to position the cap for loading salts into the salt tank outside the wash chamber. Such a solution, although it overcomes the above-mentioned problem, gives rise to many other problems for the user. When salts are loaded into the salt tank through the filler neck, in fact, some liquid, e.g. water and/or brine, always drips out of the filler neck of the salt tank. In the case of a filler neck with an external cap, therefore, some liquid will leak outside the household appliance, with evident inconvenience.

[0012] A need is therefore increasingly felt for a dishwasher safety system avoiding the risk of contamination and/or pollution of the water network and/or salt tank. In particular, a need is increasingly felt for a safety system avoiding the presence in the salt tank of agents contained in the wash and/or rinse water, and preventing them from reaching the water supply network.

[0013] In general, the present invention aims at solving these and other technical problems by providing a safety system against contamination of the water supply network, and in particular for preventing contamination of the salt tank of a water treatment system, comprising means adapted to prevent contamination and/or pollution of the water supply network, and in particular to prevent contamination of the salt tank of a water treatment system.

[0014] Furthermore, the present invention aims at solving these and other technical problems by providing a water treatment system comprising a safety system, in turn comprising means adapted to prevent contamination and/or pollution of the water supply network, and in particular to prevent contamination of the salt tank.

[0015] In particular, one possible aspect of the present invention aims at solving a technical problem occurring in the situation in which the filler neck for loading salts is within the wash chamber, by providing a safety system comprising, in turn, means adapted to prevent contamination of the water supply network, and in particular to prevent contamination of the salt tank. Even more in particular, one aspect of the present invention aims at solving the technical problem occurring in the above-mentioned situation by providing a water treatment system comprising a safety system, in turn comprising means adapted to prevent contamination of the water supply network, and in particular to prevent contamination of the salt tank.

[0016] Preferably, the safety system is adapted to communicate with a control unit of a dishwashing machine in order to signal at least a potential risk of contamination and/or pollution, for the purpose of avoiding that the potential risk might translate into actual pollution and/or contamination, e.g. by inhibiting the start of a wash cycle.

[0017] One aspect of the present invention concerns a safety system comprising means adapted to prevent contamination and/or pollution of the water supply network, e.g. to prevent contamination and/or pollution of a tank adapted to contain salts, comprised in the water treatment system.

[0018] In particular, one aspect of the present invention relates to a water treatment system having the features set out in the appended claim 1.

[0019] A further aspect of the present invention relates to a dishwashing machine having the features set out in the appended claim 11.

[0020] Yet another aspect of the present invention relates to a method for controlling a dishwashing machine having the features set out in the appended claim 12.

[0021] Auxiliary features are set out in respective dependent claims appended hereto.

[0022] The features and advantages of the safety system, water treatment system, dishwashing machine and control method will become apparent from the following description of some possible exemplary embodiments of the safety system, water treatment system, dishwashing machine and control method, as well as from the annexed drawings, wherein:

• Figure 1 schematically shows a first possible embodiment of a water treatment system comprising a safety system according to the present invention;
• Figure 2 schematically shows a second possible embodiment of a water treatment system comprising a safety system according to the present invention;
• Figure 3 schematically shows a third possible embodiment of a water treatment system comprising a safety system according to the present invention;
• Figure 4 schematically shows one possible embodiment of a safety system according to the present invention, coupled to a filler neck for loading salt into a tank of a water treatment system;
• Figure 5 shows one possible embodiment of a dishwashing machine;
• Figure 6 shows a block diagram of the control system of a dishwashing machine 1, with which a safety system can communicate, according to the present invention;
• Figure 7 schematically shows another possible embodiment of a safety system according to the present invention, coupled to a filler neck for loading salt into a tank of a water treatment system.

[0023] With reference to the above-mentioned figures, reference numeral 3 designates a safety system according to the present invention. Reference numeral 2 designates as a whole a water treatment system according to the present invention; while reference numeral 1 designates as a whole a dishwashing machine.

[0024] Safety system 3 is particularly suitable for application to a water treatment system 2 of a dishwashing machine 1.

[0025] Safety system 3 according to the present invention is adapted to prevent contamination and/or pollution of the water supply network or water mains; in particular, it is adapted to prevent contamination and/or pollution of a tank 6, e.g. the tank adapted to contain salts, comprised in water treatment system 2. More in particular, safety system 3 is adapted to prevent contamination of the water mains and/or of tank 6 caused by wash and/or rinse liquids of a dishwashing machine 1.

[0026] Safety system 3 according to the present invention comprises, in turn, means 30 adapted to prevent contamination and/or pollution of the water supply network, preferably contamination and/or pollution of tank 6, more preferably contamination caused by wash and/or rinse liquids of a dishwashing machine 1.

[0027] In general, said means 30 of safety system 3 are electronic and/or mechanical means, in particular electric and/or mechanical, or electromechanical, devices and/or mechanisms.

[0028] A further aspect of the present invention is a water treatment system 2 for a dishwashing machine 1.

[0029] Preferably, said water treatment system 2 comprises a supply line 21 connected to a water supply network, through which water is supplied into water treatment system 2. Moreover, said water treatment system 2 comprises a decalcification system 4, in turn comprising: at least one first tank 5, adapted to contain ion-exchange resins; and at least one second tank 6, adapted to contain salts.

[0030] In general, said second tank 6 comprises a filler neck 60 for adding salts into tank 6. Said filler neck 60 can be sealingly closed by means of a cap 63. In a preferred embodiment, said cap 63 can be tightened onto said filler neck 60 by screwing, e.g. by means of threaded portions.

[0031] In a preferred, though illustrative and non-limiting, embodiment of water treatment system 2, it is envisaged that the second tank 6, adapted to contains salts, is positioned under the bottom of a wash chamber 12 of dishwashing machine 1. Even more preferably, the second tank 6 is equipped with a filler neck 60 that passes through the bottom wall, preferably made of sheet steel, of wash chamber 12, whereon a through hole 121 can be made. In such an embodiment, filler neck 60 is located in the lower part of wash chamber 12, in proximity to a sump 11 for recovery of the water used during the various phases and/or programs of dishwashing machine 1.

[0032] In an alternative embodiment of water treatment system 2, not shown, it is envisaged that said filler neck 60 is positioned at or in proximity to a door 10 of dishwashing machine 1.

[0033] In an alternative embodiment of water treatment system 2, not shown, said filler neck 60 goes through a side wall of wash chamber 12 of dishwashing machine 1, e.g. via a through hole 121.

[0034] In general, safety system 3 according to the present invention is applicable to all water treatment systems 2 described above and/or currently known in the art, being thus able to prevent contamination of the water supply network, and in particular of salt tank 6.

[0035] Preferably, safety system 3 according to the present invention is comprised in said water treatment system 2.

[0036] In this embodiment, said means 30 of safety system 3 are adapted to prevent contamination and/or pollution of the second tank 6 adapted to contain salts, comprised in water treatment system 2. In particular, said means 30 are adapted to prevent contamination from wash and/or rinse fluids of dishwashing machine 1.

[0037] In an alternative embodiment, not shown, of safety system 3 according to the present invention, it is a kit that can be associated with an existing water treatment system 2 and/or dishwashing machine 1 for the purpose of preventing pollution of the water supply network, e.g. by preventing pollution of salt tank 6.

[0038] More in general, said safety system 3 may be adapted to prevent contamination and/or pollution of other parts of water treatment system 2 and/or of dishwashing machine 1, so as to avoid any contamination and/or pollution caused by a possible pressure drop in the water mains.

[0039] Describing now more in detail some possible embodiments of safety system 3 according to the present invention, in a preferred, but non-limiting, first embodiment, e.g. the embodiment wherein said means 30 are at least electronic and/or electromechanical, or at least one of said means 30 is electronic and/or electromechanical, said safety system 3 is adapted to communicate with a control unit 81 of dishwashing machine 1 in order to signal at least a potential risk of contamination and/or pollution. In particular, communication between safety system 3 and said control unit 81 occurs in order to signal at least a potential risk of contamination of the second tank 6 from wash and/or rinse liquids. In one possible embodiment, said control unit 81 is comprised in control system 8 or mainboard of dishwashing machine 1.

[0040] Preferably, in the present embodiment one or more of said means 30 are sensor means (31, 33, 34) adapted to detect particular operating conditions of one or more parts of dishwashing machine 1, e.g. of water treatment system 2, for the purpose of signalling a potential danger and/or risk. The signal indicating a potential danger and/or risk of pollution and/or contamination will be transmitted to control unit 81 in order to avoid that a potential risk and/or danger might translate into actual pollution and/or contamination of the water supply network, e.g. through contamination of said tank 6.

[0041] Upon reception of such a signal by the safety system 3, control unit 81 of dishwashing machine 1 may take several possible countermeasures. Such countermeasures may vary as concerns both the signal provided to the user and the parts of dishwashing machine 1 involved when implementing the countermeasures. For example, dishwashing machine 1 may just signal a possible danger or risk of pollution to the user, requesting the latter to take action, and/or it may prevent the activation of various programs of dishwashing machine 1 in the event of a potential danger and/or risk, e.g. by disabling one or more devices of dishwashing machine 1. In addition and/or as an alternative, the dishwashing machine may execute procedures to at least attempt to restore the situation prior to the potential risk or danger, attempting to remove any contamination already occurring in a part of water treatment system 2 and/or of dishwashing machine 1, e.g. by activating the drain circuit and/or decalcification system 4 in order to regenerate the ion-exchange resins. These and other countermeasures may be implemented by dishwashing machine 1 according to the case.

[0042] Describing more in detail the construction of said embodiment, safety system 3 may comprise a data processing and transmission unit. Said sensor means (31, 33, 34) are connected to said unit.

[0043] Alternatively, said sensor means (31, 33, 34) of safety system 3 are suitably connected to control system 8, and in particular to control unit 81 of dishwashing machine 1.

[0044] More in general, said safety system 3 may comprise means 30, which are exclusively mechanical, adapted to avoid, more preferably prevent, contamination of the water supply network, more preferably contamination of the second tank 6 of decalcification system 4.

[0045] This embodiment of safety system 3 provides means 30 in the form of mechanisms and/or devices adapted to prevent contamination and/or pollution, e.g. by generating barriers preventing the contaminant and/or pollutant from reaching a predetermined area of water treatment system 2 and/or of dishwashing machine 1, e.g. in compliance with the current regulations.

[0046] A preferred embodiment of safety system 3 employs a plurality of means 30 in order to provide redundancy in preventing contamination and/or pollution of the water supply network, e.g. a plurality of means 30 adapted to prevent contamination and/or pollution of second tank 6 adapted to contain salts. More preferably, such plurality of means 30 have different nature and/or operation, so as to ensure mutual covering in the event of a failure or malfunction of one typology of implemented means 30. For example, it may be convenient to realize a safety system 3 comprising both electronic means 30 and also mechanical means and/or electromechanical means. Moreover, if more than one electronic means 30 are used, it may be appropriate to envisage that they have different principles of operation, being adapted, for example, to monitor and/or detect different operating conditions, e.g. sensors using different technologies and/or adapted to detect and/or monitor different aspects, such that allow avoiding the risk of pollution and/or contamination. Furthermore, if more than one mechanical means 30 are used, it may be appropriate to envisage that they prevent contamination in different ways.

[0047] In one possible embodiment of said means 30 of safety system 3, they may be coupled to said second tank 6 and/or to other parts of water treatment system 2, which are preferably in fluidic communication with said second tank 6.

[0048] In other embodiments of said means 30 of safety system 3, they may be coupled to other parts or components of water treatment system 2, such as, for example, supply line 21 and/or the line connected to inlet 51 of the first tank 5 of decalcification system 4.

[0049] In one possible embodiment of said mechanical means 30, they comprise at least one mechanical device 32. Said mechanical device 32 is adapted to prevent contamination and/or pollution of tank 6.

[0050] In a preferred embodiment, said at least one mechanical device 32 is connected to a cap 63 to automatically close a filler neck 60 comprised in tank 6. Said at least one mechanical device 32 is adapted to keep said filler neck 60 normally closed by means of said cap 63.

[0051] In one possible embodiment, said mechanical device 32 comprises a mechanism for closing cap 63, adapted to close said filler neck 60 of the second tank 6. Said closing mechanism is adapted to keep said filler neck 60 normally closed by means of said cap 63. In one possible embodiment, said closing mechanism comprises a connection portion, to which said cap 63 is connected, a fastening portion, which is fastened to a part of the same filler neck 60 and/or of wash chamber 12. Said connection portion of the closing mechanism is hinged to said fastening portion. Said closing mechanism further comprises at least one elastic means and/or yielding means adapted to hold said cap 63 in the position in which it closes said filler neck 60, preferably in order to ensure hydraulic tightness. The connection between the connection portion and the fastening portion via an elastic and/or yielding means permits cap 63 to be moved away from the filler neck when salts need to be added into said tank 6. When said operation of adding salts into tank 6 is finished, the closing mechanism will, without requiring the user to take any action, move cap 63 back in position to close said filler neck 60, preferably ensuring hydraulic tightness.

[0052] In an alternative embodiment of said at least one mechanical device 32, it is placed in a cap adapted to close said filler neck 60. In the present embodiment, said at least one mechanical device 32 is adapted to effect a double hydraulic sealing. In one possible embodiment of said mechanical device 32, it comprises a pair of gaskets 322, e.g. two O-rings, adapted to ensure tightness in both direction of flow of the fluid, whether from the outside towards filler neck 60 or from filler neck 60 towards the outside, e.g. towards wash chamber 12. As an alternative, said mechanical device 32, and in particular said pair of gaskets 322, is at least partly associated with filler neck 60.

[0053] In a further embodiment of said mechanical device 32, it is an additional cap 324 adapted to co-operate with existing cap 63 to provide a further means 30 adapted to prevent contamination and/or pollution of the water supply network, in particular by preventing contamination and/or pollution of the second tank 6.

[0054] In a further embodiment, said safety system 3 comprises at least one mechanical device 32, which is at least one valve element 326.

[0055] In a preferred embodiment, said valve element 326 is a check valve, in particular a ball-type check valve, capable of avoiding any pollution and/or contamination of the water supply network, particularly in the event of a pressure drop in the water mains. Said valve element 326 may be applied along supply line 21 of water treatment system 2, for the purpose of preventing any backflow towards the water supply network or water mains in case of a pressure drop in the latter. In addition or as an alternative, said valve elements 326 may be applied along the line directed towards inlet 51 of the first tank 5 of decalcification system 4 of water treatment system 2.

[0056] In one possible exemplary, but non-limiting, embodiment, said safety system 3 comprises a plurality of means 30, implemented as mechanical devices 32 adapted to prevent contamination, comprising a mechanism for closing cap 63, an additional cap 324, at least one valve element 326 and/or a pair of gaskets 322.

[0057] More in general, said safety system 3 preferably comprises at least one mechanical device 32 in the form of a mechanism for closing cap 63, which is adapted to automatically close said filler neck 60 of tank 6 by means of said cap 63, preferably comprising an elastic element, such as a spring adapted to keep said filler neck 60 normally closed by means of said cap 63.

[0058] In a further possible embodiment of said means 30, they are of the electromechanical type. In the present embodiment, said means 30 comprise at least one electromechanical device 35. Said electromechanical device 35 is adapted to prevent contamination and/or pollution of tank 6.

[0059] In one possible exemplary embodiment, said at least one electromechanical device is connected to a cap 63, and the same electromechanical device 35 is controllable by a control system 8 of the dishwashing machine, e.g. said electromechanical device is controllable by control unit 81. Said electromechanical device 35 is adapted to keep said filler neck 60 comprised in tank 6 in a closed condition, preventing the removal of at least one cap (63, 324). Said control system 8, and in particular said control unit 81, is adapted to control said electromechanical device 35 to selectively allow or prevent the removal of at least one cap (63, 324). Said at least one electromechanical device 35 is therefore adapted to keep said filler neck 60 normally closed by means of at least one cap (63, 324). In one possible embodiment, said electromechanical device is adapted to prevent the rotation of at least one cap (63, 324), thereby preventing said cap from being unscrewed from said filler neck 60.

[0060] Said control system 8, and in particular said control unit 81, will only allow said at least one cap (63, 324) to be removed in the appropriate configurations ofdishwashing machine 1, e.g. only when it is necessary to refill said tank 6 with salts, and/or it will then check that said at least one cap (63, 324) has been positioned in a correct manner.

[0061] The present embodiment may thus comprise all the advantages brought about by the solutions respectively comprising mechanical and electronic means, with the addition of further technical advantages attainable from implementations of electromechanical solutions, which can be controlled in accordance with control system 8, in particular with said control unit 81, of dishwashing machine 1.

[0062] Said electromechanical device 35 may comprise an actuator adapted to move an element capable of selectively preventing the removal of at least one cap (63, 324) from said tank 6, e.g. it may comprise a linear actuator and a pin adapted to be inserted into said at least one cap (63, 324), thereby preventing removal thereof. Other implementations equally adapted to prevent the removal of at least one cap (63, 324), not illustrated and/or described herein, using at least one electromechanical device 35, should be considered as implicitly described in the present description.

[0063] In one possible embodiment of safety system 3 according to the present invention, said means 30 are, as aforementioned, of the electronic type. In particular, said means 30 comprise at least one sensor means (31, 33, 34). In general, said sensor means (31, 33, 34) is adapted to detect an operating condition of dishwashing machine 1 and/or of water treatment system 2 in which there is at least a potential risk of pollution and/or contamination of the water mains, in particular of the second tank 6.

[0064] In a preferred, but non-limiting, embodiment of said sensor means, it is a sensor 31 at least adapted to sense the presence of a predetermined pressure in a portion of a hydraulic circuit of dishwashing machine 1, such as, for example, the pressure inside tank 6 of a decalcification system 4 of water treatment system 2.

[0065] Describing the construction more in detail, in a preferred embodiment said at least one sensor 31 is a level sensor adapted to measure the level reached by a liquid at a particular point of the circuit of decalcification system 4 of water treatment system 2. In fact, by monitoring the fluid level it is possible to determine if there is a pressure drop in the water supply network or water mains, which might lead to contamination and/or pollution of the water supply network, or if the filler neck 60 of tank 6 is not properly closed by at least one cap (63, 324). Said level sensor 31 is therefore adapted to provide feedback about the presence of pressure inside salt tank 6 because, if there is fluid up to that level, this means that there is pressure in tank 6 from the water supply network, and also that said filler neck 60 is hydraulically sealed by at least one cap (63, 324).

[0066] Said level sensors 31 may be of the optical type, adapted to determine optical reflection to detect the presence of water at a given point of decalcification system 4. As an alternative, the sensors may use different technologies, e.g. float-type electromechanical sensors.

[0067] More in general, said level sensor 31 may be placed, for example, in a duct leading to the second tank 6 of decalcification system 4 and/or of water treatment system 2, or directly within tank 6.

[0068] In one possible alternative embodiment, said at least one sensor 31 is a pressure sensor adapted to measure a relative pressure. Said pressure sensor 31 is located, for example, within salt tank 6 and/or in a duct of the circuit of the water treatment system, e.g. in the supply line 21. Such pressure may be generated, for example, by the presence of a liquid instead of atmospheric pressure.

[0069] More in general, said sensor 31 may be any sensor adapted to determine the presence of a predetermined pressure inside tank 6 and/or to detect any leaks from cap 63 associated with filler neck 60 and/or a pressure drop in the water supply network.

[0070] In general, said safety system 3, being adapted to communicate with a control unit 81 of dishwashing machine 1, is capable of signalling the presence of a predetermined pressure, thereby making it possible to determine if there is a potential risk of contamination and/or pollution of said tank 6. For example, if level sensor 31 detects the absence of a predetermined pressure, then safety system 3 will communicate with said control unit 81 of dishwashing machine 1 to signal a potential risk of contamination and/or pollution of said tank 6. As an alternative, in the embodiment wherein said sensor 31 is directly connected to said control unit 81, it will be the very control unit 81 that will determine the potential risk of contamination and/or pollution of said tank 6.

[0071] In such an operating condition, dishwashing machine 1 may, for example, issue an alarm signal to the user. Such alarm signal may indicate to the user that it is necessary to verify the presence of cap 63 on filler neck 60. This signalling is particularly useful, for example, if dishwashing machine 1 had previously signalled to the user that salts were lacking in the second tank 6, in which case the user may have forgotten to position cap 63 back on filler neck 60 after having filled the same tank 6.

[0072] In general, dishwashing machine 1 may, when it receives a signal indicating a potential risk of contamination via control unit 81, stop the wash cycle and/or make verifications to check for the actual presence of cap 63 on filler neck 60, such as, for example, activating the supply circuit by outputting a supply pulse in order to verify the presence of at least one cap (63, 324) on filler neck 60, while monitoring the variations perceived by said sensor 31.

[0073] In another preferred, but non-limiting, embodiment of said sensor means, it is a sensor 33 at least adapted to detect the presence of at least one cap (63, 324) on top of a filler neck 60 of tank 6. Said at least one cap may be cap 63, already present and adapted to close filler neck 60, or may be a mechanical device 32 of the same safety system 3 adapted to close said filler neck 60 of tank 6, such as, for example, said additional cap 324.

[0074] Said sensor 33 is preferably a position sensor. Said position sensor 33 is adapted to determine if said at least one cap (63, 324) is in a predetermined position, in particular with respect to filler neck 60, so as to ensure hydraulic tightness.

[0075] In an alternative embodiment, said sensor 33 is a presence sensor adapted to determine the presence of said at least one cap in proximity to said filler neck 60 of the second tank 6.

[0076] Said sensor 33 may be located on at least one cap (63, 324), preferably on both, and/or near the opening of filler neck 60. Said sensor 33 may be placed in a housing formed in cap (63, 324) and/or in filler neck 60, preferably in proximity to the opening of filler neck 60 whereon said at least one cap (63, 324) is fastened. As an alternative, said sensor may be an optical sensor, which may even be located in a remote area away from said filler neck 60, for monitoring the presence of the cap.

[0077] More in general, said sensor 33 may be made by using any technology suitable for determining the presence of at least one cap (63, 324) on filler neck 60.

[0078] As in the preceding embodiment of the sensor means, said safety system 3 can, being adapted to communicate with a control unit 81 of dishwashing machine 1, signal the correct positioning of at least one cap (63, 324) on top of a filler neck 60 of tank 6, so as to determine if there is a potential risk of contamination and/or pollution of said tank 6. For example, if sensor 33 detects the absence of the caps, then safety system 3 will communicate with said control unit 81 of dishwashing machine 1 to signal a potential risk of contamination and/or pollution of said tank 6. As an alternative, in the embodiment wherein said sensor 33 is directly connected to said control unit 81, it will be control unit 81 itself that will determine the potential risk of contamination and/or pollution of said tank 6.

[0079] In such an operating condition, dishwashing machine 1 may, for example, issue an alarm signal to the user. Such alarm signal may indicate to the user that it is necessary to verify the presence of cap 63 on filler neck 60, as specified by way of example for the preceding embodiment.

[0080] In general, dishwashing machine 1 may, when it receives a signal for a potential risk of contamination via control unit 81, stop the wash cycle and/or make verifications to check for the actual presence of cap 63 on filler neck 60, e.g. it may activate the supply circuit by outputting a supply pulse in order to verify the presence of at least one cap (63, 324) on the filler neck. Optionally, dishwashing machine 1 may suitably activate the drain circuit by turning on a drain pump.

[0081] In general, a safety system 3 comprising a plurality of electronic means 30, in particular sensor means (31, 33, 34), makes it possible to eliminate any risk of contamination of the water supply network that may be caused by a particular operating condition of dishwashing machine 1, even in case one or more of said sensor means (31, 33, 34) are damaged and/or malfunctioning.

[0082] A particularly advantageous possible embodiment of safety system 3 comprises a plurality of electronic means 30, in particular sensor means (31, 33, 34), and in particular at least one sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank 6, and at least one sensor 33 at least adapted to detect the presence of cap 63 on top of filler neck 60.

[0083] The present solution is particularly advantageous because it is possible both to determine the presence or absence of at least one cap on the filler neck 60 while also checking for cap tightness and detecting any infiltration that may be caused, for example, by a cap not ensuring tightness because incorrectly positioned or due to failures, e.g. of the gaskets. In fact, the use of a level sensor allows detecting the entrance of any undesired liquid into tank 6, and hence the onset of contamination and/or pollution of the second tank 6.

[0084] Just like the previously described embodiments, said safety system 3 can, being adapted to communicate with a control unit of dishwashing machine 1, signals to the dishwashing machine the onset of a potential risk of contamination and/or pollution of said tank 6.

[0085] In such an embodiment, the countermeasures that dishwashing machine 1 may adopt include, as in the previous embodiments, activating an alarm, e.g. by monitoring both sensor means (31, 33) after receiving the signal indicating lack of salt in the second tank 6, and stopping the wash cycle while activating a supply pulse to check for the presence of the cap, etc.

[0086] Since it envisages dual control provided by two different sensors, the present implementation solution eliminates the problem of a defective signal due to, for example, a malfunction of either one of the two sensors (31, 33). The present solution allows obtaining a safety system 3 capable of complying with the requirements of the regulation currently in force at low implementation costs.

[0087] A particularly advantageous embodiment of safety system 3 according to the present invention comprises means 30 that comprise at least one sensor means, e.g. at least one sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank 6, and/or at least one sensor 33 at least adapted to detect the presence of cap 63 on top of filler neck 60, and at least one mechanical device 32, e.g. comprising a mechanism for closing cap 63, an additional cap 324 and/or a valve element 326.

[0088] The present embodiment makes it possible to combine electronic devices adapted to prevent the onset of contamination, by signalling those operating conditions which might cause contamination, together with mechanical devices 32 adapted to prevent contamination. The present solution, since it uses means 30 adapted to prevent contamination and/or pollution via different approaches, provides redundancy that will still ensure that contamination will be prevented even in case of a malfunction of one of means 30 included in safety system 3. The present solution allows obtaining a safety system 3 capable of complying with the requirements of the regulation currently in force at low implementation costs.

[0089] One preferred possible embodiment of safety system 3 comprises a sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank 6, and at least one mechanical device 32 comprising a mechanism for closing cap 63.

[0090] A further possible embodiment of safety system 3 comprises a plurality of electronic means 30, and in particular at least one sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank 6, and at least one sensor 33 at least adapted to detect the presence of cap 63 on top of filler neck 60, and at least one mechanical device 32 comprising a mechanism for closing cap 63.

[0091] As an alternative, said safety system 3 comprises at least one sensor 33 at least adapted to detect the presence of cap 63 on top of filler neck 60 and at least one mechanical device 32 comprising a mechanism for closing cap 63.

[0092] Another preferred possible embodiment of safety system 3 comprises a sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank 6, and at least one mechanical device 32 in the form of a valve element 326, in particular a ball-type check valve.

[0093] Yet another possible embodiment of safety system 3 comprises a plurality of electronic means 30, and in particular at least one sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank 6, and at least one sensor 33 at least adapted to detect the presence of cap 63 on top of filler neck 60, and at least one mechanical device 32 in the form of a valve element 326, in particular a ball-type check valve.

[0094] As an alternative, said safety system 3 comprises at least one sensor 33 at least adapted to detect the presence of at least a cap (63, 324) on top of filler neck 60 and at least one mechanical device 32 in the form of a valve element 326, in particular a ball-type check valve.

[0095] In a further alternative embodiment, said safety system 3 comprises an electromechanical device 35 adapted to prevent the removal of at least one cap (63, 324), and an additional means 30, which may be an electronic means (31, 33, 34) among those previously described and/or a mechanical means 30, e.g. a mechanical device 32 among those previously described.

[0096] In all of the above-described embodiments of safety system 3, said safety system 3 is adapted to communicate with a control unit 81 of dishwashing machine 1, so that dishwashing machine 1 is enabled to take any necessary countermeasures as previously specified, such as, for example, alarms and/or machine stop and/or interruption of phases and/or programs of dishwashing machine 1, and/or activation of the drain circuit and/or execution of a procedure of regeneration of the ion-exchange resins contained in the first tank 5 of the decalcification system, possibly in addition to preventing the removal of at least one cap (63, 324) associated with said filler neck.

[0097] In general, all the solutions proposed herein as regards the implementation of safety system 3 are low-cost ones, particularly the above-illustrated implementation solutions having a plurality of means 30, which ensure full compliance with the specifications of the regulations currently in force, e.g. the EN 61770 regulation.

[0098] In a further alternative embodiment of safety system 3 according to the present invention, said sensor means is a detergent presence sensor 34. Said detergent presence sensor 34 is adapted to detect the presence of detergent within a portion of water treatment system 2, e.g. within the second tank 6, adapted to contain salts.

[0099] Describing the construction more in detail, in a preferred embodiment said at least one detergent presence sensor 34 is a sensor adapted to sense conductivity, in particular the conductivity of the fluid it is immersed in; an optical sensor, e.g. adapted to determine the reflectivity of the fluid it is immersed in; a sensor adapted to sense the PH of the fluid it is immersed in; and/or a capacitive sensor, adapted to determine the relative capacitance of the medium interposed between the two electrodes.

[0100] More in general, said detergent presence sensor 34 may be adapted to detect the presence of other contaminating and/or polluting substances, such as, for example, rinse aid.

[0101] Therefore, the present solution makes it possible to determine if there is any contaminating and/or polluting liquid, e.g. detergent and/or rinse aid, in a portion of water treatment system 2, e.g. inside the second tank 6. Hence, the present detergent presence sensor 34 prevents contamination and/or pollution of the water supply network, in particular by detecting any contamination of the second tank 6 of decalcification system 4.

[0102] Said detergent presence sensor 34 is preferably positioned within the second tank 6 and/or in a channel in fluidic communication with said second tank 6, e.g. where it is possible to position the previously described sensor 31.

[0103] In general, said safety system 3 can, being adapted to communicate with a control unit 81 of dishwashing machine 1, signal the presence of a predetermined quantity of detergent and/or rinse aid within salt tank 6, thereby making it possible to determine if there is a potential risk of contamination and/or pollution of said tank 6. For example, if the presence of a predetermined quantity of detergent and/or rinse aid is detected by sensor 34, then safety system 3 will communicate with said control unit 81 of dishwashing machine 1 to signal a potential risk of contamination and/or pollution of said tank 6. As an alternative, in the embodiment wherein said sensor 34 is directly connected to said control unit 81, it will be control unit 81 itself that will determine the potential risk of contamination and/or pollution of said tank 6. In such an operating condition, dishwashing machine 1 may, for example, issue an alarm signal to the user. Such alarm signal may indicate to the user that it is necessary to verify the presence of cap 63 on filler neck 60.

[0104] In general, dishwashing machine 1 may, when it receives a signal for a potential risk of contamination via the control unit, stop the wash cycle and/or make verifications to check for the actual presence of cap 63 at filler neck 60, as previously described.

[0105] Preferably, dishwashing machine 1 carries out the necessary activities to decontaminate tank 6 from the contaminant contained therein, e.g. activating the drain circuit and/or executing a procedure for regenerating the ion-exchange resins contained in the first tank 5 of decalcification system 4.

[0106] In a preferred embodiment of said water treatment system 2 for a dishwashing machine 1, it comprises a supply line 21 through which water is supplied to water treatment system 2; and a decalcification system 4. Said decalcification system 4 in turn comprises: at least one first tank 5, adapted to contain ion-exchange resins; and at least one second tank 6, adapted to contain salts. Said decalcification system 4 comprises a first circuit adapted to conduct water coming from supply line 21 towards an inlet 51 of said first tank 5; and a second circuit adapted to conduct water towards an inlet of said second tank 6.

[0107] Water treatment system 2 further comprises a delivery line 22, connected to an outlet 52 of the first tank 5, through which water having the desired hardness level comes out of water treatment system 2; and an electromechanical actuator, e.g. a pump 27, adapted to define, at least partly, the quantity of water per time unit to be supplied into said second circuit and/or said second tank 6.

[0108] Said water treatment system 2 further comprises an air break 27 and a safety system 3 according to the present invention.

[0109] In addition to said filler neck 60 and said cap 63, said second tank 6 also comprises at least one inlet 61, through which water enters into said second tank 6, and an outlet 62, through which a regeneration fluid for the ion-exchange resins, e.g. brine, flows out.

[0110] Said water treatment system 2 according to the present invention is particularly suitable for being included in a dishwashing machine 1. Preferably, said dishwashing machine 1 comprises a wash chamber 12, a door 10 and a sump 11. Said dishwashing machine 1 preferably comprises a through hole 121 formed in said wash chamber 12, preferably in the bottom base of said wash chamber, through which said filler neck 60 of the second tank 6 of decalcification system 4 of water treatment system 2 passes.

[0111] Said dishwashing machine 1 further comprises a control system 8 or mainboard, which comprises at least one control unit 81. Said control system 8 is adapted to electrically control all the electric and electronic devices comprised in dishwashing machine 1. Said control system 8 comprises a memory medium 82, preferably a non-volatile memory medium, which stores the various wash programs of dishwashing machine 1 and the machine instructions for controlling the individual electric and electronic devices comprised in the dishwashing machine as required for each operating phase and program of dishwashing machine 1.

[0112] Said control system 8 communicates with the electronic systems and devices comprised in dishwashing machine 1 and in the various systems and/or circuits included therein via suitable communication lines. In particular, said safety system 3 is adapted to communicate with said control unit 81 either directly, if the sensor means are directly connected to said control unit 81, or through a processing and transmission unit comprised in safety system 3 itself.

[0113] In the embodiment in which said safety system comprises electromechanical means 30, said control system 8, and in particular control unit 81, is adapted to drive at least one electromechanical device 35, e.g. in order to selectively prevent the removal of said at least one cap (63, 324) .

[0114] Said processing and transmission unit is adapted to receive electric and electronic signals from the different sensor means (31, 33, 34) and/or from said electromagnetic device 35 comprised in safety system 3, to process them, and to appropriately send them to said control unit 81. The conformation of said processing and transmission unit will depend on the type and number of sensors and/or electromechanical devices comprised in safety system 3 according to the present invention.

[0115] As aforementioned, one or more memory media 82 of control system 8 of a dishwashing machine 1 suitably store the operating programs of dishwashing machine 1 and any information coming from the systems comprised in dishwashing machine 1, e.g. from safety system 3 according to the present invention.

[0116] Preferably, said memory medium 82 stores a sequence of machine instructions adapted to execute a method for controlling a dishwashing machine 1 according to the present invention.

[0117] Preferably, said method for controlling a dishwashing machine 1 according to the present invention comprises the following steps, preferably to be carried out in succession:

• activating dishwashing machine 1;
• executing a wash program;
• deactivating dishwashing machine 1.

[0118] The control method according to the present invention envisages that, if a safety system 3 according to the present invention detects at least a potential risk of contamination and/or pollution of the water supply network, preferably a potential risk of contamination and/or pollution of a tank 6, then a step of deactivating dishwashing machine 1 will be carried out. The control method envisages that said step of deactivating dishwashing machine 1 should be carried out independently of the step of the control method currently in progress. Therefore, if the control method is executing a wash program and an electronic signal is received from safety system 3 which indicates that safety system 3 has detected a potential risk of contamination and/or pollution, then the wash program will be immediately interrupted and the control program will execute a step of deactivating dishwashing machine 1. Deactivating dishwashing machine 1 refers to any operating condition that will prevent any contamination and/or pollution from propagating in the dishwashing machine itself or, even worse, towards the water supply network or the second tank 6. Therefore, such deactivation may simply involve stopping the water supply pump and/or closing one or more valve elements.

[0119] In general, the method according to the present invention may comprise a step or substep of preventing the removal of at least one cap. This step may be executed prior to the detection of a potential risk of contamination and/or pollution, e.g. simultaneously with the step of activating dishwashing machine 1, for the purpose of avoiding that a situation of potential risk of contamination and/or pollution might occur. As an alternative, said step may be carried out after the detection of a potential risk of contamination and/or pollution, e.g. as a countermeasure to prevent the situation from getting worse. Said step may be implemented by appropriately activating an electromechanical device 35 comprised in safety system 3. In particular, said electromechanical device 35 is driven by control system 8 of dishwashing machine 1, and in particular by control unit 81.

[0120] The control method preferably comprises a monitoring and/or interrogation step, wherein control system 8, and in particular control unit 81, monitor safety system 3 to verify if the safety system is transmitting signals, and/or interrogates safety system 3 while activating it, in order to verify if there is a risk of contamination and/or pollution. The monitoring and/or interrogation step may also be carried out upon reception of a signal indicating the detection of a potential risk of contamination and/or pollution from safety system 3, for the purpose of verifying if any countermeasures adopted by the dishwashing machine have avoided the risk of contamination and/or pollution.

[0121] Preferably, the control method envisages steps wherein control unit 81 interrogates safety system 3. In particular, this step is carried out in case any operations are executed on the dishwashing machine which might put the same dishwashing machine into a configuration in which it may be subject to a potential risk of pollution and/or contamination, e.g. when a signal concerning the lack of salts in the second tank 6 has been issued, assuming that upon receiving such signal the user has taken care of adding salts into said tank 6, thus potentially placing the machine into a configuration subject to a potential risk of contamination. In fact, the user may forget to put cap 63 back on filler neck 60 and/or tighten it incorrectly, i.e. not enough to ensure hydraulic tightness or so much as to cause it to break, resulting in potential infiltration, or may forget to reposition other components, such as gaskets, etc.

[0122] In general, the control method can handle subprocesses or subroutines that can be activated upon the occurrence of a particular event, such as, for example, the signal received from an electronic device, e.g. a sensor of safety system 3.

[0123] In general, the control method according to the present invention includes, following the step of deactivating dishwashing machine 1, a step of activating a drain circuit comprised in dishwashing machine 1. In the present step, control system 8 of the dishwashing machine suitably controls the drain pump of the drain circuit to eliminate any contaminants and/or pollutants from dishwashing machine 1. In fact, some embodiments of safety system 3 according to the present invention require dishwashing machine 1 to take appropriate countermeasures to avoid the propagation of any potential contaminants or pollutants within dishwashing machine 1, e.g. within water treatment system 2. For example, in the solutions envisaging the detection of a variation inside the second tank 6, e.g. a pressure or level variation and/or a quantity of contaminating and/or polluting fluid, it is necessary to take the necessary countermeasures to sanitize the second tank 6 from the contaminant/pollutant. For example, dishwashing machine 1 may turn on said drain circuit, in particular the drain pump, and/or decalcification system 4 to execute, for example, a procedure of regenerating the ion-exchange resins contained in the first tank 5, e.g. by activating said pump 27 to supply water into the second tank 6.

[0124] Preferably, the control method according to the present invention envisages that, after the step of deactivating dishwashing machine 1, the machine will remain in that operating state as long as safety system 3 keeps sensing an operating configuration subject to a potential risk of contamination and/or pollution.

[0125] More in general, the detection of potential contamination and/or pollution by safety system 3 may be processed by an algorithm that will exclude the possibility of any false signals. This algorithm may change as a function of the number and type of sensor means comprised in safety system 3.

[0126] The control method according to the present invention includes a signalling step, wherein dishwashing machine 1 provides the user with visual and/or audible feedback about the condition of potential risk of pollution and/or contamination. This signalling step may be carried out, for example, as previously specified. For example, said signalling step may indicate the possible risk source, prompting the user to take adequate countermeasures to eliminate the risk of contamination and/or pollution, e.g. checking the condition of cap 63, checking if it has been positioned correctly, checking if all the parts thereof are present, and checking if hydraulic tightness is ensured by the cap on filler neck 60. On this occasion, the user can verify the condition of cap 63 and remove any obstacles or restore the proper operation, so that cap 63 will hydraulically seal said filler neck 60.

[0127] Safety system 3 according to the present invention makes it possible to comply with one or more requirements of the regulation currently in force.

[0128] With reference to the embodiments illustrated in the present invention, Figure 1 schematically shows a first possible embodiment of a water treatment system 2 comprising a safety system 3 according to the present invention.

[0129] Water treatment system 2 illustrated in the drawing comprises a supply line 21, through which water enters water treatment system 2. The quantity of water supplied is suitably measured by a flowmeter. Downstream of supply line 21 there is at least one air gap 23. Downstream of the air gap 23, the duct continues up to inlet 51 of the first tank 5, which is adapted to contain ion-exchange resins. Inlet 51 of the first tank 5 is located at one end, preferably the bottom end, of the same tank 5. At the opposite end of the first tank 5 there is an outlet 52, which is connected to the delivery line 22 of water treatment system 2. The illustrated embodiment includes a second tank 6, which is in fluidic communication with said first tank 5. In particular, the outlet of said first tank 5 is connected to inlet 61 of said second tank 6. Outlet 62 of the second tank 6 is then connected, through a pump 27, to inlet 51 of the first tank 5, so that it is possible, by suitably activating pump 27, to deliver water into the second tank 6 and regeneration liquid, in particular brine, into said first tank 5, as is known to a person skilled in the art.

[0130] Said second tank 6 comprises a filler neck 60, which is closed by a cap 63.

[0131] Water treatment system 2 according to the illustrated embodiment comprises a safety system 3, which comprises a means 30, in particular a sensor means, consisting of a sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank 6 of decalcification system 4. In particular, said sensor 31 is a level sensor adapted to measure the level reached by the liquid in delivery line 22 of water treatment system 2. The position of sensor 31 shown herein is merely indicative and, as previously specified, said sensor 31 may be implemented with several possible technologies.

[0132] Figure 2 schematically shows a second possible embodiment of a water treatment system 2 comprising a safety system 3 according to the present invention.

[0133] Water treatment system 2 and decalcification system 4 shown therein are substantially similar to those illustrated in Figure 1.

[0134] Unlike the embodiment shown in Figure 1, in the embodiment shown in Figure 2 means 30 of safety system 3 is placed in a different location of water treatment system 2. In fact, said means 30 is located in the second tank 6 of decalcification system 4. The position shown is merely indicative.

[0135] Said means 30 is a sensor means, which may be either a sensor 31 adapted to detect the presence of both a predetermined pressure inside the second tank 6 and a detergent presence sensor 34, which is adapted to detect the presence of any pollutant and/or contaminant, e.g. detergent and/or rinse aid, within the second tank 6.

[0136] More in detail, said sensor 31 may be a level sensor and/or a pressure sensor; whereas said detergent presence sensor 34 may be one of those previously listed.

[0137] The schematic indications of means 30 of safety system 3 shown in Figures 1 and 2 do not exclude the possibility of including more than one means 30, whether mechanical or electronic.

[0138] Figure 3 schematically shows a third possible embodiment of a water treatment system 2 comprising a safety system 3 according to the present invention.

[0139] The illustrated embodiment shows a different embodiment of water treatment system 2, in particular of a portion thereof, which is different from the embodiment shown in Figures 1 and 2.

[0140] Figure 3 shows only a portion of water treatment system 2, decalcification system 4 not being visible, which could be implemented by using either the same technology shown in Figures 1 and 2 or other implementation solutions known to a person skilled in the art. In fact, in this figure one can see the channels to which both inlet 51 of the first tank and inlet 61 of the second tank of decalcification system 4 may be connected. The figure shows supply line 21, in proximity to which there is a flowmeter. The figure also shows the position of air break 23.

[0141] The illustrated embodiment of water treatment system 2 includes a safety system 3, which in turn comprises a plurality of means 30 of different nature, which are adapted to prevent contamination and/or pollution from wash liquid of a tank 6.

[0142] In fact, safety system 3 comprises mechanical devices in the form of valve elements 326. In the illustrated embodiment, in proximity to air break 23 there is a valve element 326, consisting of a ball-type check valve.

[0143] Moreover, in the channel connected to inlet 51 of the first tank there are two valve elements 326 in the form of non-return valves arranged in series.

[0144] Safety system 3 shown in Figure 3 further comprises a sensor means, which is a sensor 31 adapted to detect the presence of a predetermined pressure inside the second tank of decalcification system 4. In particular, said sensor 31 is a level sensor adapted to measure the level reached by the liquid in the line connected to inlet 61 of the second tank. The position of sensor 31 shown herein is merely indicative.

[0145] Figure 4 schematically shows one possible embodiment of a safety system 3, coupled to a filler neck 60 of a tank 6, according to the present invention. In the illustrated embodiment, one can see cap 63 and an additional cap 324, the latter being arranged deeper within filler neck 60 of the second tank 6. The illustrated safety system 3 also comprises, in addition to said additional cap 324, other mechanical means 30, including a pair of gaskets 322, in particular two O-rings.

[0146] Filler neck 60 is adapted to protrude into wash chamber 12 of the dishwashing machine, and the corresponding hole in the wall of the wash chamber is sealed by means of a ring-type gasket.

[0147] In the illustrated embodiment, safety system 3 further comprises an additional means 30 consisting of a sensor means. Said sensor means is a sensor 33 adapted to detect the presence of at least one cap (63, 324) on top of a filler neck 60 of tank 6. In the illustrated embodiment, said sensor 33 is a sensor capable of sensing the presence of additional cap 324. Such sensor 33 is, for example, a reed sensor, suitably connected to a printed circuit board and adapted to detect the presence of a magnet included in said additional cap 324.

[0148] The illustrated position and type of sensor 31 are merely indicative, and so is the choice regarding which one of the caps (63, 324) is to be monitored by it.

[0149] Figure 5 shows one possible embodiment of a dishwashing machine 1. In this figure one can see dishwashing machine 1 in a condition in which door 10 is open, for better understanding the position of water treatment system 2, and in particular of cap 63 of the second tank 6, which protrudes from a through hole 121 formed in the bottom of wash chamber 12. Figure 5 also shows the position of sump 11.

[0150] The position of cap 63, and hence of the second tank 6, is merely indicative, since it is also possible to apply safety system 3 according to the present invention to dishwashing machines 1 having cap 63 located in other positions, e.g. on door 10.

[0151] Figure 6 shows a block diagram of control system 8 of a dishwashing machine 1, adapted to control the different parts of the same dishwashing machine 1.

[0152] In particular, the control system, more specifically control unit 81, is adapted to communicate with said safety system 3 according to the present invention.

[0153] The image is merely diagrammatic, but it clearly shows the presence of a communication line between safety system 3 and control system 8, which is used in order to prevent contamination and/or pollution of the water supply network, and in particular of the second tank 6 adapted to contain salts and comprised in water treatment system 2.

[0154] Safety system 3 according to the present invention is adapted to communicate with a control unit 81 of dishwashing machine 1 in order to signal at least a potential risk of contamination and/or pollution, in particular pollution from wash and/or rinse liquid, of said second tank 6.

[0155] Figure 7 schematically shows another possible embodiment of a safety system 3 according to the present invention, coupled to a filler neck 60 for loading salts into a tank 6 of a water treatment system 2.

[0156] In the illustrated embodiment, one can see cap 63 adapted to close filler neck 60 of the second tank 6. The illustrated safety system 3 comprises other mechanical means 30, including a pair of gaskets 322, in particular two O-rings.

[0157] Filler neck 60 is adapted to protrude into wash chamber 12 of the dishwashing machine, and the corresponding hole in the wall of wash chamber 12 is sealed by means of a ring-type gasket.

[0158] In the illustrated embodiment, safety system 3 further comprises an additional means 30, which is an electromechanical device 35. Said electromechanical device 35 is adapted to keep said cap 63 in a closed condition on top of a filler neck 60 of tank 6, thereby preventing the removal of said cap 63. In the illustrated embodiment, said electromechanical device 35 comprises a linear actuator adapted to move a pin interacting with said cap 63 in order to selectively prevent it from being removed from filler neck 60.

[0159] The position and type of electromechanical actuator 35 shown herein are merely indicative.

[0160] Safety system 3 according to the present invention provides a simple, quick and low-cost solution to ensure safety against the risk of contamination and/or pollution, in particular from wash and/or rinse liquids, without the need for implementing any complex and expensive devices as suggested by the prior art.

[0161] Safety system 3 according to the present invention is particularly suitable for ensuring that dishwashing machine 1 will be enabled to work when cap 63 is properly closed and operational to hydraulically seal said filler neck 60 of the second tank 6.

[0162] More in particular, safety system 3 according to the present invention is particularly suitable for application to a water treatment system 2 comprising a second tank 6 positioned under the bottom of wash chamber 12, wherein the second tank 6 comprises a filler neck 60 passing through a through hole 121 made in the sheet-metal bottom of wash chamber 12.

[0163] Said safety system 3 may comprise one or more means 30, wherein said means may be either electronic or mechanical.

[0164] In particular, particularly advantageous are those solutions wherein safety system 3 comprises a mechanical device 32 comprising a mechanism for closing cap 63, adapted to close said filler neck 60, and a mechanical device 32 consisting of at least one valve element 326 in the form of a ball-type check valve.

[0165] Particularly advantageous are also those solutions wherein safety system 3 comprises a mechanical device 32, consisting of at least one valve element 326 in the form of a ball-type check valve, and a sensor means, consisting of a sensor 31 at least adapted to detect the presence of a predetermined pressure in a portion of a hydraulic circuit of dishwashing machine 1.

[0166] Furthermore, particularly advantageous are also those solutions wherein safety system 3 comprises a mechanical device 32 comprising a mechanism for closing cap 63 adapted to close said filler neck 60, and a sensor means consisting of a sensor 31 at least adapted to detect the presence of a predetermined pressure in a portion of a hydraulic circuit of dishwashing machine 1.

[0167] Particularly advantageous are also those solutions wherein safety system 3 comprises at least one electromechanical device 35 and at least one electronic means 30, e.g. a sensor means (31, 33, 34), and/or one mechanical means 30, e.g. a mechanical device 32.

[0168] Such solutions are particularly economical because they have a low impact on the moulds used for manufacturing water treatment system 2, while however ensuring compliance with the requirements of the regulations currently in force.

[0169] More in general, said safety system 3 can be applied to any existing water treatment system 2 and/or dishwashing machine 1 either as a separate kit or as a system integrated into dishwashing machine 1. In particular, safety system 3 can be integrated into an existing dishwashing machine having mechanical and/or electronic devices capable of verifying the position of the cap of salt tank 6 and/or of parts of dishwashing machine 1, e.g. door 10 of dishwashing machine 1.

[0170] It must be pointed out that all the embodiments of safety system 3, water treatment system 2 and dishwashing machine 1 described and/or illustrated herein only represent a limited selection of some possible embodiments of the present invention. In fact, the single technical features of any embodiment may be combined with other features shown in other embodiments to create different embodiments, which shall be considered as implicitly described in the present patent application.

REFERENCE NUMERALS

Dishwashing machine	1
Door	10
Sump	11
Wash chamber	12
Through hole	121
Water treatment system	2
Supply line	21
Delivery line	22
Air break	23
Pump	27
Safety system	3
Means	30
Sensor (pressure)	31
Mechanical device	32
Gaskets	322
Cap	324
Valve element	326
Sensor (presence)	33
Detergent presence sensors	34
Electromechanical device	35
Decalcification system	4
First tank	5
Inlet	51
Outlet	52
Second tank	6
Filler neck	60
Inlet	61
Outlet	62
Cap	63
Control system	8
Control unit	81
Memory medium	82

Claims

1. Water treatment system (2) for a dishwashing machine (1); comprising a safety system (3) in turn comprising means (30) adapted to prevent contamination and/or pollution from wash liquid of a tank (6) adapted to contain salts, comprised in the water treatment system (2);
said safety system (3) being adapted to communicate with a control unit (81) comprised in the dishwashing machine (1), in order to signal at least a potential risk of contamination and/or pollution of said tank (6).

2. System according to claim 1, wherein said means (30) comprise at least one sensor (31) at least adapted to detect the presence of a predetermined pressure inside the tank (6).

3. System according to any one of the preceding claims, wherein said means (30) comprise at least one sensor (33) at least adapted to detect the presence of at least one cap (63, 324) on top of a filler neck (60) of the tank (6).

4. System according to any one of the preceding claims, wherein said means (30) comprise at least one detergent presence sensor (34), adapted to detect the presence of detergent inside the tank (6).

5. System according to claim 2, wherein said at least one sensor (31) is a pressure sensor and/or a level sensor.

6. System according to claim 4, wherein said detergent presence sensor (34) is:

- a sensor adapted to sense conductivity;

- an optical sensor;

- a sensor adapted to sense the PH; and/or

- a capacitive sensor.

7. System according to any one of the preceding claims, wherein said means (30) comprise at least one mechanical device (32) adapted to prevent contamination and/or pollution of the tank (6).

8. System according to claim 7, wherein said at least one mechanical device (32) is connected to a cap (63) to automatically close a filler neck (60) comprised in the tank (6); said at least one mechanical device (32) being adapted to keep said filler neck (60) normally closed by means of said cap (63).

9. System according to claim 7 or 8, wherein said at least one mechanical device (32) is placed in said cap (63); said at least one mechanical device (32) being adapted to effect a double hydraulic sealing on said cap (63) .

10. System according to any one of the preceding claims, wherein said means (30) comprise at least one electromechanical device (35) adapted to prevent contamination and/or pollution of the tank (6).

11. Dishwashing machine (1) comprising: a wash chamber (12), a door (10) and a sump (11); characterized in that it comprises a water treatment system (2) according to claim 1.

12. Method for controlling a dishwashing machine (1) according to claim 11, comprising the following steps:

- activating the dishwashing machine (1);

- executing a wash program;

- deactivating the dishwashing machine (1);
characterized in that, if a safety system (3) detects at least a potential risk of contamination and/or pollution of a tank (6), a step of deactivating the dishwashing machine (1) will be carried out, regardless of the step of the control method that is currently being executed.

13. Method according to claim 12, wherein the step of deactivating the dishwashing machine (1) is followed by a step of activating a drain circuit comprised in the dishwashing machine (1).

14. Method according to claim 12 or 13, comprising a step of preventing the removal of at least one cap;
said step being implemented by suitably activating an electromechanical device (35) comprised in the safety system (3).

Drawing