DESCRIPTION

The subject matter of the invention is a filter cartridge for a machine for preparing beverages of the type suitable for being housed in a tank connected to the feed circuit of the machine for treating the water present therein.

In the context of the reference technical sector, it is known to use machines for preparing coffee and hot beverages in general, which are provided with a tank intended to contain the water required for preparing the beverage. The presence of such a tank is typically required in machines for domestic use, to avoid connecting the machine to the water supply network and at the same time to ensure a sufficient amount of water in order to provide a sufficient number of coffee portions.

For the purpose of improving the quality of the water present in the tank, for example by removing impurities present therein or by softening it, it is also known that replaceable cartridge filter systems can be used in coffee machines, such as the one described in patent application WO 2012/146567 Al .

Patent application WO 2012/146567 relates to a replaceable cartridge filter comprising two separate chambers holding an appropriate ion exchange material . This filter is configured such that the liquid to be treated is divided into a first and second fraction, separate from each other, which are filtered exclusively by the first and second chamber, respectively.

The first and second fraction of the liquid thus filtered are collected in an outlet conduit which is open at the bottom and intended for discharging the treated liquid from the cartridge filter.

In one embodiment, a bypass opening is also provided on the outlet conduit so that unfiltered water is not admitted through either the first or the second chamber.

The applicant has observed that, although this solution makes it possible to improve the control of the composition of the treated liquid with respect to other types of known cartridges, the filtering action proves suboptimal from a functional point of view and is not very satisfactory in terms of quality. The technical problem addressed by the present invention is therefore that of making available a filter cartridge for coffee preparation machines that is designed, in terms of structure and function, to remedy all the drawbacks reported with reference to the above-mentioned prior art.

This problem is resolved by means of a filter cartridge for a machine for preparing coffee and hot or cold beverages in general, produced according to claim 1.

Preferred features of the invention are defined in the dependent claims. The teaching according to the present invention allows excellent filtering of the liquid to be treated and, at the same time, improved control of the composition of the liquid treated.

Furthermore, the cartridge according to the present invention is of relatively compact dimensions, making it easy to use.

The features and other advantages of the invention will be more clearly apparent from the following detailed description of a preferred but not exclusive embodiment thereof, which is indicative and non-restrictive, with reference to the attached drawings, in which : • Fig. 1 is a schematic sectional view of a first embodiment of a filter cartridge according to the invention;

• Fig. 2 is a schematic sectional view of a second embodiment of a filter cartridge according to the invention; and

• Fig. 3 is a schematic sectional view of a third embodiment of a filter cartridge according to the invention.

With reference initially to Fig . 1, a filter cartridge for machines for preparing beverages such as coffee, tea or barley coffee is shown with the overall reference numeral 1.

The filter cartridge 1 is of the type suitable for being installed in a tank 100 intended to contain a liquid W (for example water) to be used for preparing the beverage.

By way of example, the tank 100 can be formed by a recipient having a cylindrical structure, which defines a perimeter wall thereof, within the upper portion of which an inlet aperture 101 for pouring the water into the recipient is defined . Obviously, however, alternative shapes are also conceivable for the tank.

The tank 100 is connected to the coffee machine (not shown in the figure), in particular to the water feed circuit within it by means of a connection element 102 formed within a bottom wall 110 of the tank 100. By way of example, the connection element 102 can be produced in the form of a nozzle that is inserted into a corresponding seating (not shown in the figure), which is produced in the machine and connected to the circuit thereof.

The filter cartridge 1 comprises a main body 10, preferably elongated in shape, within which a filter material is housed, for example an ion exchange material, preferably ion exchange resins, for treating the liquid W.

With reference to Fig . 1, the filter cartridge 1 comprises a main inlet 12 for admitting liquid W to be treated into the main body 10, and an outlet 14 for discharging the treated liquid from the main body 10.

Preferably, the outlet 14 is followed by a collection chamber 20 through which the treated liquid leaving the second chamber 2 is channelled towards an outlet opening 21 in the cartridge.

Still according to a preferred embodiment, the outlet opening 21 is defined within a connecting collar 22, which can be coupled to the connection element 102 of the tank 100 in such a way that only water that has passed through the filter cartridge 1 can be supplied to the feed circuit of the machine. At any rate, in more general terms, the outlet opening 21 can be associated with the feed circuit in such a way that the water leaving said outlet is supplied to the machine for the purpose of preparing the beverage. According to a preferred embodiment, the filter cartridge 1 comprises an outer casing 23 which is connected to the main body 10 and is coupled thereto in such a way as to form an inlet channel 24 so that the liquid W to be treated can flow towards the main inlet 12. In the present embodiment, the inlet channel 24 has the shape of a cavity which is concentric with the main body 10.

Preferably, the ion exchange filter material Fl, F2 is provided only inside the main body 10 of the filter, the liquid flowing unfiltered through the inlet channel 24. In other words no filter material is provided within the inlet channel 24. This is particular advantageous if the outer casing 23 is removably coupled to the main body 10. In this manner, the main body 10 comprising the filer material, that is subjected to exhaustion, can be substituted individually from the outer casing 23.

Preferably, the outer casing 23 covers the main body 10 over substantially its entire length, leaving a common passage 28, for the liquid, defined between the bottom 110 of the tank 100 and a base portion of the outer casing 23. The liquid to be filtered inside the tank 100 can thus be drawn into the filter cartridge 1, passing through the passage 28, for example by using a suction mechanism in the machine for preparing beverages that sucks the liquid through the seating for the connection element 102. It is known that the positioning of the passage 28 within the bottom of the tank advantageously allows nearly all the liquid present therein to be used.

It should also be noted that in the tank comprising the filter cartridge of the present invention also the outlet 14 and the common passage 28 are provided at the bottom wall 110 of the tank 100.

The filter cartridge 1 further comprises a first chamber 11 containing at least one first ion exchange filter material Fl for treating the liquid W to be treated, and a second chamber 13 which is in fluid communication with the first chamber 11 and contains at least one second ion exchange filter material F2 for treating the liquid W to be treated . The chambers 11, 13 are separate from each other and, according to a preferred embodiment, are defined by the walls of the main body 10 itself and by a filter-type separation element 26, 27, which is preferably defined by a mesh filter. In the present embodiment there are two separate mesh filters, which define respective openings which allow for the passage of liquid and at the same time hold the filter material .

As will be explained below, the presence of two separate chambers allows the liquid W to be filtered in two successive stages so as to improve control of the composition of the treated liquid.

Preferably, the composition of the second ion exchange filter material F2 differs from the composition of the first ion exchange material Fl.

In one embodiment of the invention, the first ion exchange filter material Fl comprises hydrogen cations H and a type of cation among those belonging to the group consisting of sodium Na, potassium K and magnesium Mg . With regard to the second ion exchange filter material F2, this comprises cations of calcium Ca, magnesium Mg and a type of cation among those belonging to the group consisting of potassium K and sodium Na.

Because different ion exchange filter material is provided in the two chambers 11, 13, the liquid in the two chambers can be treated differently, such that the filtering actuated by one chamber is independent of the other. Moreover, this solution allows the liquid to be enriched, as it flows through each chamber 11, 13, with appropriate ancillary substances capable of giving further properties to the liquid.

With reference to the figures, the main inlet 12 and the outlet 14 are produced respectively by an inlet section of the first chamber 11 and by an outlet section of the second chamber 13.

In detail, the main inlet 12 and the outlet 14 are preferably defined by a perforated surface of the first and second chamber 11, 13, respectively, which allow the corresponding filter material Fl, F2 to be held, simultaneously allowing the liquid to flow through. Typically, the first and second filter material Fl, F2 are in the form of granules.

Preferably, the main inlet 12 and the outlet 14 are produced by means of a mesh filter.

With reference to the figures, a main filtration path 15a is defined between the main inlet 12 and the outlet 14 so that a first fraction Wl of liquid to be treated can flow through the first chamber 11 and then through the second chamber 13.

In other words, the second chamber 13 is positioned in the main body 10 in such a way that the first fraction Wl of liquid W, admitted into the main body 10 through the main inlet 12, passes through the second chamber 13 only after having passed through the first chamber 11.

With reference to the embodiments of the invention illustrated in the figures, wherein the main body 10 is shaped substantially as a cylindrical tube, or more in general as an elongate body, the first chamber 11 is thus superimposed over the second chamber 13 when the filter cartridge 1 is put into use, i.e. when the connecting collar 22 of the filter cartridge 1 is coupled to the connection element 102 of the tank 100.

According to a preferred embodiment, the common passage 28 is also provided at the same end of the main body 10.

In a preferred embodiment, the first chamber 11 is spaced apart from the second chamber 13 by the interposition of one or more intermediate chambers 25 which is/are defined between the separation elements 26 and 27, so that the first fraction Wl of liquid to be treated passes sequentially through the first chamber 11 and one or more intermediate chambers, and then into the second chamber 13.

Ion exchange filter material and/or another type of filtering means can be held within such intermediate chambers.

The main body 10 of the cartridge 1 further comprises an auxiliary inlet 19, which is separate from and independent of the main inlet 12 and intended for admitting liquid to be treated .

In particular, the auxiliary inlet 19 is defined by a perforated section of the main body 10. Preferably, the auxiliary inlet 19 is provided on the outer surface of the main body 10 and, in the present preferred embodiment, faces the intermediate chamber 25 defined between the two chambers. It should be noted that the presence of the intermediate chamber allows the already partly filtered liquid coming from the first chamber to be mixed with the unfiltered liquid coming from the tank.

The size of the section of the auxiliary inlet 19 contributes to determining the flow rate of the second fraction W2, of liquid to be treated, which is admitted into the main body 10.

The main body 10 is thus configured so as to define a filtration path 15b between the auxiliary inlet 19 and the outlet 14 so that a second fraction W2 of liquid to be treated can flow through the second chamber 13 without first passing into the first chamber 11.

The second fraction W2 of the liquid to be treated is thus a fraction of the liquid W contained in the tank 100 that is not intended to pass into the first chamber 11.

It should, moreover, be observed that at least one segment of the filtration path 15b can coincide with a segment of the filtration path 15a. Preferably, the segment of the filtration path 15b defined within the second chamber 13 coincides with that of the filtration path 15a.

In that case, a liquid is produced inside the second chamber 13 by mixing the first fraction of liquid Wl with the second fraction of liquid W2 that will be discharged from the main body 10 via the outlet 14.

In the present embodiment, the intermediate chamber 25 is arranged in the main body 10 above at least one portion of the second chamber 13 in such a way that the second fraction W2, of the liquid to be treated, which is admitted into the chamber 25 via the auxiliary inlet 19, passes into said chamber 25 and then passes into the second chamber 13, from which it is discharged via the outlet 14 after having passed through the second ion exchange filter material F2.

With reference to Fig. 1-3, the main body 10 of the filter cartridge 1 is shaped as an elongated tube, wherein the main inlet 12 and the outlet 14 are provided within longitudinally opposite portions of the main body 10. This permits optimal dimensions in relation to the length of the filtration path. Furthermore, it is particularly well suited to providing the two filtration paths described above.

When the filter cartridge 1 is put into use, i.e. when the connecting collar 22 of the filter cartridge 1 is coupled to the connection element 102 of the tank 100, the main inlet 12 and the outlet 14 are turned towards the top and bottom, respectively.

In the present embodiment, the liquid W contained in the tank 100 is impelled to rise back up the inlet channel 24 so that it is introduced into the main body 10 of the filter cartridge 1, flowing through the main inlet 12 and through the auxiliary inlet 19.

With reference now to Fig. 1, in the present embodiment, when the cartridge is in use, the first chamber 11 is superimposed over the second chamber 13 from which it is also spaced apart by the interposition of the intermediate chamber 25.

In other words, since the two chambers are arranged in an axially successive position, the first filtration path passes initially through the first chamber and then the second chamber when the liquid is drawn into the main body via the main inlet 12.

The chamber 25 is in fluid communication with both the second chamber 13 via the opening 26 and the first chamber 11 via an opening 27 which is preferably defined by a perforated section of the first chamber 11 that is able to hold the filter material Fl and, at the same time, to allow the liquid to flow through.

The chamber 25 is therefore interposed on the filtration path 15a between the first and second chamber 11, 13.

The first fraction Wl of liquid to be treated W therefore accesses the first chamber 11 via the main inlet 12, passes through the first ion exchange filter material Fl, reaches the chamber 25 through the opening 27 and finally enters the second chamber 13, in which it passes through the second ion exchange filter material F2.

The auxiliary inlet 19 is provided within a side portion of the main body 10, preferably at a distance from the main inlet 12 and the outlet 14.

In particular, the auxiliary inlet 19 is provided within the lateral wall of the conduit 25 so that the filtration path 15b of the second fraction W2 of liquid to be treated can originate in the chamber 25 and develops in the second chamber 13, avoiding passing into the first chamber 11.

It should be noted that in this embodiment of the invention the first and second fraction Wl, W2 merge in the chamber 25, and are at least partly mixed before passing into the second chamber 13.

In the second chamber 13, the first and second fraction Wl, W2 of liquid pass through the second ion exchange material F2, descending towards the outlet 14, from which the liquid treated in this way is discharged from the main body 10.

According to the invention, the first fraction of liquid Wl is therefore subject to a first treatment carried out by the first ion exchange material Fl followed by a second treatment carried out by the second ion exchange material F2. Treatment of the second fraction of liquid W2 is, however, limited to the second ion exchange material F2.

This solution makes it possible to lengthen the filtration path of at least one fraction of liquid to be treated so as to increase the filtering time to which it is subjected in order to obtain optimal purification of the treated liquid and, at the same time, permits better control of the composition of the liquid treated .

The provision of the filtration path 15b according to the invention ensures that the second fraction W2 of liquid is filtered by the second ion exchange filter material F2 in an unrelated and independent manner from the first ion exchange filter material Fl, so that its composition is not influenced by the first filter material.

If, instead, the second fraction W2 of liquid were also treated by the first ion exchange filter material Fl, control of the composition of the treated liquid would be compromised by the variability of the ion exchange process owing to the different substances present in the two ion exchange materials used .

The variation in the dimensions of the section of the auxiliary inlet 19 also allows effective control of the composition of the treated liquid.

In the embodiment in Fig . 2, the auxiliary opening 19 is produced within the upper end of the main body 10 and is connected to the intermediate chamber 25 by a conduit 25', which preferably extends in parallel with the first filtration path through the first chamber 25.

The auxiliary inlet 19 is thus provided close to the main inlet 12 and preferably extends therearound .

The present embodiment advantageously makes it possible to avoid the presence of the auxiliary inlet 19 in an intermediate position along the channel 24, thus favouring a more uniform flow towards the main and auxiliary inlets.

With reference to Fig. 3, according to another embodiment, the chambers 11 and 12 can communicate directly, that is, without the intermediate chamber 25 being interposed. In that case, the conduit 25' communicates directly with the second chamber 13 without the liquid entering from the auxiliary inlet 19 being mixed first with that coming out of the chamber 11. This solution makes it possible to obtain a longer filtration path than in the previous embodiments, although this is to the detriment of the mixing effect of the previous embodiments, which allows more homogeneous filtration to take place in the second chamber. The invention thus remedies the problem posed and at the same time offers a plurality of advantages, including providing excellent filtering action and better control of the composition of the treated liquid. Furthermore, the filter cartridge according to the invention is of relatively compact dimensions, making it easy to use.