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(11) | EP 2 564 753 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Water-softening device containing anhydrous salt |
| (57) The water-softening device for softening water supplied to an electrical household
appliance comprises: a first tank (10) for containing substances with water-softening
properties; a second salt-containing tank (14), having at least one water inlet opening
(20); and a chamber (16) for containing brine formed as a result of the entry of water
into the second tank (14) and the dissolution of the salt contained therein and intended
for regenerating the water-softening substances. The chamber (16) is located below
the second tank (14), to which it is hydraulically connected, and is provided with
a discharge conduit (26) directed towards said first tank (10).
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[0001] The present invention relates to a water-softening device for softening water supplied to an electrical household washing machine, such as a dishwasher or a washing machine for laundry purposes.
[0002] More specifically, a device of this type comprises:
- a first tank for containing substances with water-softening properties, and
- a second salt-containing tank, having at least one water inlet opening.
[0003] The operating cycle of this device is such that, after a predetermined number of passages of supplied water through the water-softening substances, the latter, which are typically ion exchange resins, are regenerated by the passage of a brine formed in the second tank as a result of the entry of water into this tank, which causes the dissolution of some of the salt contained therein.
[0004] In one example of the prior art, the salt tank always contains brine. Therefore, when the salt is topped up in order to restore the amount used up, the brine may overflow out of the inlet used for topping up. In the case of a dishwasher, the leaked brine may be discharged through the well of the washing chamber, causing problems of corrosion of any metal parts with which it may come into contact. In the case of a washing machine, this possible discharge route does not exist, and therefore the situation becomes even more problematic.
[0005] The object of the present invention is to provide a water-softening device which is improved with respect to the prior art devices, and which is, in particular, free of the drawbacks mentioned above.
[0006] According to the invention, this object is achieved by means of a water-softening device of the type indicated at the beginning of the present description, characterized in that it comprises a chamber for containing a brine formed as a result of the entry of water into the second tank and the dissolution of the salt contained therein and intended for regenerating said water-softening substances, said chamber being located below the second tank to which it is hydraulically connected, and being provided with a discharge conduit which is directed towards said first tank and is provided with a pump.
[0007] In the device according to the invention, the salt contained in the corresponding tank is anhydrous, since the brine formed as a result of previous entries of water into the tank and not yet supplied to the resin tank is accumulated in the underlying chamber. Thus the top-up operations are facilitated because the anhydrous salt can flow much more easily than wet salt, and does not come into contact with the pre-existing brine, thus avoiding the risk that the brine may overflow to the outside of the tank.
[0008] Furthermore, the presence of a pump in the chamber discharge conduit, which is directed towards the first tank, provides a simple way of measuring the quantity of regeneration brine used. This pump can also overcome the effect of gravity, thus increasing the freedom of the positioning of the tanks and chamber: in particular, the first tank can be positioned at a higher level than the level of the chamber.
[0009] Advantageously, the second tank and the chamber are provided with corresponding means for monitoring the water level inside them, these means producing signals which can be used for the control of the operation of the pump and the sending of the regeneration brine towards the substances with water-softening properties.
[0010] A further object of the present invention is an electrical household washing machine comprising a water-softening device of the type described above.
[0011] Further advantages and characteristics of the present invention will be made clear by the following detailed description, which refers to the attached drawings provided by way of non-limiting example, in which:
Figure 1 is a schematic view of a device according to the invention during the step of water softening,
Figure 2 is a schematic view of the device of the preceding figure during the step of formation of the regeneration brine, and
Figure 3 is a schematic view of the device of the preceding figures during the step of the flow of the regeneration brine through the water-softening resins.
[0012] A water-softening device for softening water supplied to an electrical household appliance comprises a first tank 10, for containing substances with water-softening properties, and a casing 12 in which a second tank 14 for containing salt and a chamber 16 are formed. The chamber is positioned below the tank 14, from which it is separated by a porous partition placed horizontally, such as a filter 18, so as to provide a hydraulic connection.
[0013] The second tank 14 is provided with a plurality of openings 20, communicating with a water supply conduit 22, which has a shut-off valve 24, and with a discharge conduit 26, on which a pump 28 is positioned, this conduit being directed towards the first tank 10. The tank 14 also has an inlet 30 for topping up the salt.
[0014] The second tank 14 and/or the chamber 16 can be provided with means for monitoring and/or measuring the level of water and/or salt inside them. In particular, the second tank 14 and the chamber 16 are provided with corresponding means for monitoring the water level inside them.
[0015] In a known way, the first tank 10 is provided with a water supply conduit 32 having a shut-off valve 34 and a discharge conduit 36. The first tank 10 is also advantageously positioned at a higher level than the level of the chamber 16.
[0016] During the water-softening step (see Figure 1, arrow 38), the water supplied by the conduit 32 passes through the first tank 10, is softened by the resins contained therein, and is finally sent to the washing chamber of the electrical household appliance. During this step there is no flow of water through the second tank 14.
[0017] In order to carry out the regeneration step, the valve 24 is first opened (see Figure 2, arrow 40), thus causing a flow of water in the conduit 22 towards the second tank 14. In this tank a brine is formed, which flows out through the filter 18 into the chamber 16, until it reaches, for example, the level 42 in the tank 14 located above, to which the chamber 16 is hydraulically connected. The pump 28 is then activated (see Fig. 3, arrow 44), in such a way that the brine passes through the resins contained in the first tank 10 and regenerates them until its level in the chamber 16 falls to the point identified by the reference numeral 46. Advantageously, the pump 28 can also act as a gauge of the volume of regeneration brine, thus allowing a precise measured dose to be sent to the first tank 10. At this point, the operation of the pump 28 is stopped, and consequently the flow of brine through the tank 10 ceases, causing the operation of regenerating the resins contained in the tank 10 to be terminated.
[0018] In these conditions, which are those normally prevailing in the water-softening device except in the regeneration step, the salt remaining in the tank 14 is completely anhydrous. Consequently, when the salt becomes depleted, it can be topped up through the inlet 30, this procedure being aided by the greater fluidity of the salt, without any risk of leakage of the brine, which is contained in the underlying chamber 16, separately from the salt.
1. Water-softening device for softening water supplied to an electrical household appliance,
comprising:
- a first tank (10) for containing substances with water-softening properties, and
- a second salt-containing tank (14), having at least one water inlet opening (20), said device being characterized in that it comprises a chamber (16) for containing brine formed as a result of the entry of water into the second reservoir (14) and the dissolution of the salt contained therein and intended for regenerating said water-softening substances, said chamber (16) being located below the second tank (14) to which it is hydraulically connected and being provided with a discharge conduit (26) directed towards said first tank (10) and provided with a pump (28).
2. Device according to Claim 1, wherein said second tank (14) and said chamber (16) are
formed within a single casing (12), within which they are separated by a porous partition,
such as a filter (18).
3. Device according to any one of the preceding claims, wherein said first tank (10)
is located at a level higher than the level of said chamber (16).
4. Device according to any one of the preceding claims, wherein said second tank (14)
and said chamber (16) are provided with respective means for monitoring the water
level inside.
5. Device according to any one of the preceding Claims 1 to 3, wherein said second tank
(14) and/or said chamber (16) are provided with means for monitoring and/or measuring
the water and/or salt level inside them.
6. Device according to any one of the preceding claims, wherein said pump (28) also acts
as a gauge of the volume of brine formed as a result of the entry of water into the
second tank (14) and the dissolution of the salt contained therein and intended for
regenerating said water-softening substances in the first tank (10).
7. Electrical household washing appliance comprising a water-softening device according
to any one of the preceding claims.