MINERALIZATION CARTRIDGE AND METHOD FOR THE OPERATION THEREOF

Abstract

The invention relates to a method for operating a water filter cartridge in a pipe, said water filter cartridge having a housing in the form of a pressure vessel, and an inlet and an outlet for water, characterized in that a main flow of water to which minerals are added is conducted through a main pipe inside the pressure vessel, and a dosing flow of concentrated salt solution is conducted through a dosing pipe, wherein the dosing pipe branches off from the main pipe and passes through a reservoir of constant volume and in which there is a concentrated salt solution consisting of sulphate salt, chloride salt and/or hydrogen carbonate salt, wherein the part of the dosing pipe extending from the reservoir leads into the main flow at a dosing point through a dosing opening with a constant flow cross-section, and wherein a resistance section which is situated upstream of the dosing point in the main flow is used to set the flow resistance in the main flow such that a pressure difference results between the main flow and the dosing flow and causes a volumetric flow rate of the dosing flow of salt solution which is substantially proportional to the main flow, through the dosing opening opening into the main flow.

Claims

1) A method for operating a mains-fitted water filter cartridge (1) having a housing (2) in the form of a pressure vessel, having an inlet (4) and having an outlet (5) for water, characterized in that inside the pressure vessel a main flow (6.1) of water, to which minerals are added, is conducted through a main conduit (6) and a dosing flow (7.1, 9.6) of concentrated salt solution (11) is conducted through a dosing conduit (7.2, 9.5, 9.7), wherein the dosing conduit (7.2) branches off from the main conduit (6) and leads through a storage vessel (9) of constant volume which contains a concentrated salt solution (11) formed of sulfate salt, chloride salt and/or hydrogencarbonate salt, wherein the part (9.7) of the dosing conduit departing from the storage vessel (9) opens into the main flow (6.1) at a dosing point (9.8) via a dosing opening (9.7; 13.2) having a constant flow cross section, and wherein the flow resistance in the main flow (6.1) is set by means of a bed of a granular material (6.3) forming a resistance section (6.5) in the main flow (6.1), which is arranged upstream of the dosing point (9.8) in the direction of flow, and by means of a separate resistance section (7.5), in the form of a resistance layer (7.4) and/or of a capillary, in the dosing flow (7.1, 9.6), the feed of which section projects into the preceding bed, such that a differential pressure arises between the main flow (6.1) and the dosing flow (7.1, 9.6), this differential pressure bringing about a volume flow of the dosing flow (7.1, 9.6) of the salt solution (11; 11′), through the dosing opening (9.7; 13.2) that opens into the main flow, which is substantially proportional to the main flow (6).

2. The method as claimed in claim 1, characterized in that the storage vessel (9) contains a salt bed (10) formed of sulfate salt, chloride salt and/or hydrogencarbonate salt and hence a storage volume of concentrated salt solution (11) is formed downstream of the salt bed (10) in the direction of flow.

3. The method as claimed in claim 1 characterized in that the resistance section formed in the dosing section or in the dosing flow (7.1, 9.6) is in the form of a bed of a granular material (6.3) and/or in the form of a capillary which has an internal diameter in a range from 0.1 to 0.5 mm, in particular between 0.15 and 0.4 mm.

4. The method as claimed in claim 1 characterized in that, with the water filter cartridge (1) in the operational orientation, with the outlet (5) directed upwards, the main flow (6) coming from the inlet (4) is conducted from the top to the resistance section (6.5) so that it flows through the resistance section (6.5) from top to bottom.

5. The method as claimed in claim 1 characterized in that, with the water filter cartridge (1) in the operational orientation, with the outlet (5) directed upwards, the main flow (6) coming from the inlet (4) is conducted to the underside of the resistance section (6.5) so that it flows through the resistance section (6.5) from bottom to top.

6. The method as claimed in claim 2 characterized in that at least one concentrated salt solution (11; 11′) of sulfate salts, chloride salts or hydrogencarbonate salts is used, the solubility of these being at least 2 g/l at 20° C., preferably at least 50 g/l at 20° C., especially 740 g/l at 20° C.

7. The method as claimed in claim 2 characterized in that the at least one salt solution (11; 11′) is dosed at a proportion by volume of 0.05% to 2% to the main flow (6).

8. The method as claimed in claim 1 characterized in that a granular material (6.3; 7.3) with a particle size of 0.1 mm to 2 mm is used for the bed which in particular has a minimum extent (6.4; 7.4) of 1 cm in the direction of flow.

9. The method as claimed in claim 1 characterized in that the same granular material (6.3; 7.3) is used for the resistance section (7.5) of the dosing flow (7; 7′) and the resistance section (6.5) of the main flow (6).

10. The method as claimed in claim 1 characterized in that the conductance of the water between the inlet (4) and outlet (5) is raised by at least 100 μS/cm to 2000 μS/cm, preferably by 600 μS/cm.

11. The method as claimed in claim 1 characterized in that the water filter cartridge (1) is operated at a pressure of from 0.2 bar to 8.0 bar.

12. The method as claimed in claim 2 characterized in that the salt solution (11; 11′) is temporarily stored in a temporary store for the salt solution (13; 13′) between its exit point (9.7) from the at least one storage vessel (9) and the dosing point for the salt solution (9.8) into the main flow (6) of the water, which temporary store for the salt solution is preferably made from a flexible material and in particular is arranged substantially horizontally in the operational position of the water filter cartridge.

13. The method as claimed in claim 10, characterized in that the temporary store (13; 13′) used for the salt solution is a hose with a filling volume of 0.05 ml to 0.3 ml.

14. The method as claimed in claim 10 characterized in that the temporary store (13; 13′) used for the salt solution is a hose with a length of 5 cm to 30 cm and in particular a diameter of 0.5 mm to 3 mm.

15. A mains-fitted water filter cartridge (1), comprising a housing (2) in the form of a pressure vessel, an inlet (4) and an outlet (5) for water, characterized in that provided inside the pressure vessel are a main conduit (6) for conducting a main flow (6.1) of water, to which minerals are intended to be added, and a dosing conduit (7.2, 9.5, 9.7) for conducting a dosing flow (7.1, 9.6) of concentrated salt solution (11), wherein the dosing conduit (7.2, 9.5, 9.7) branches off from the main conduit (6) and comprises a storage vessel (9) of constant volume which contains a salt solution (11) formed of sulfate salt, chloride salt and/or hydrogencarbonate salt, wherein the part (9.7) of the dosing conduit departing from the storage vessel (9) is connected to the main flow (6.1) at a dosing point (9.8) via a dosing opening (9.7) having a constant flow cross section, and wherein a bed of a granular material (6.3) forming a resistance section (6.5) is arranged in the main conduit (6) upstream of the dosing point (9.8) in the direction of flow, and a separate resistance section (7.5), in the form of a resistance layer (7.4) and/or of a capillary, is formed in the dosing flow (7.1, 9.6), the feed of which section projects into the preceding bed, and the flow resistance of which is set such that a differential pressure arises between the main flow (6.1) and the dosing flow (7.1), this differential pressure bringing about a volume flow of the dosing flow (7) of the salt solution (11; 11′), through the dosing opening (9.8) that opens into the main flow (6), which is substantially proportional to the main flow (6).

16. The mains-fitted water filter cartridge as claimed in claim 15, characterized in that the storage vessel contains a salt bed (10) formed of sulfate salt, chloride salt and/or hydrogencarbonate salt and hence a storage volume of concentrated salt solution (11) is present downstream of the salt bed (10) in the direction of flow.

17. The mains-fitted water filter cartridge as claimed in claim 15 characterized in that the resistance section (7.4) forming the dosing section or the dosing flow (7.1) is in the form of a bed of a granular material (6.3) and/or in the form of a capillary which has an internal diameter in a range from 0.1 to 0.5 mm, in particular between 0.17 and 0.35 mm.

18. The mains-fitted water filter cartridge as claimed in claim 15 characterized in that a temporary store for the salt solution (13; 13′) is provided between the exit point for the salt solution (9.7; 9.7′) from the at least one storage vessel (9; 9′) and the dosing point for the salt solution (9.8; 9.8′), which temporary store is arranged preferably substantially horizontally in the operational position of the mains-fitted water filter cartridge (1).

19. The mains-fitted water filter cartridge as claimed in claim 15 characterized in that the temporary store for the salt solution (13; 13′) is a hose which preferably has a filling volume of 0.05 ml to 0.3 ml.

20. The mains-fitted water filter cartridge as claimed in claim 15 characterized in that the hose is 5 cm to 30 cm long and has a diameter of 0.5 to 3 mm.

21. The mains-fitted water filter cartridge as claimed in claim 15 characterized in that the resistance section (7.5) of the dosing flow (7) and the resistance section (6.5) of the main flow (6) are composed of the same granular material (6.3; 7.3).

Description

EXEMPLARY EMBODIMENTS

[0076] Exemplary embodiments are described in more detail below with reference to the appended figures.

[0077] In the figures:

[0078] FIG. 1: schematically shows by way of example a water filter cartridge in plan view marked with a longitudinal section A-A and a horizontal section/cross section B-B.

[0079] FIG. 2: schematically shows by way of example an illustration of a section through a water filter cartridge, along longitudinal section A-A according to FIG. 1, in a first embodiment.

[0080] FIG. 3: schematically shows by way of example an illustration of a section through the water filter cartridge according to FIG. 1 in the first embodiment, along horizontal section/cross section B-B.

[0081] FIGS. 4 and 5:

[0082] schematically show by way of example two illustrations of sections through the water filter cartridge according to FIG. 1 in a second embodiment, along longitudinal section A-A and along horizontal section/cross section B-B, respectively.

[0083] FIG. 6 to 8:

[0084] schematically show by way of example further details concerning the construction of the water filter cartridges.

[0085] FIGS. 9 and 10:

[0086] in turn schematically show by way of example two further embodiments with an internal construction which differs from the designs operating in pressure mode in FIG. 2 to B in that they function in accordance with the suction principle.

[0087] Accordingly, FIG. 1 shows the illustration of a mains-fitted water filter cartridge 1 having a housing 2, comprising a wall 2.1, a base 2.2, a cover 2.3 and a neck 2.4.

[0088] Three fastening elements 2.4.1 are shown at the neck 2.4, for example arranged distributed around this neck. Using these fastening elements, the filter cartridge 1 can be fastened in a complementary mains-fitted connection head (not shown), after it has been inserted in said connection head, and thereafter brought into operation.

[0089] A protective cap 3 covers and closes in FIG. 1 in a detachable manner the connection region of the filter cartridge (cf. FIG. 2).

[0090] Along the longitudinal axis 1.1 which runs through the housing of the filter cartridge there are shown a vertically running sectional line A-A and, transversely thereto and approximately in the upper third of the housing, a horizontally running sectional line B-B. These are relevant for the subsequent figures.

[0091] FIG. 2 shows an illustration of a section through the filter cartridge 1 along sectional line A-A from FIG. 1. In this are illustrated in the sectional state: housing 2, wall 2.1, base 2.2, and cover 2.3 placed on the end face opposite the base and having an adjoining neck 2.4.

[0092] In this neck 2.4 an outlet 5 protruding in the manner of a pipe is formed centrally on the inside for the exit of the water to be treated by the filter cartridge. An inlet 4 into the cylindrical-conical filter cartridge 1 for the water to be treated surrounds this outlet coaxially and is delimited by the outer wall 2.4.2 of the neck 2.4. Arrows 4.1 and 5.1 symbolize the flow direction of the water to be treated.

[0093] A detachable protective cap 3 protects these inlet and outlet regions 4, 5 of the filter cartridge 1, in particular against contamination and/or damage, for example of the connection and/or sealing structures.

[0094] A passage 4.2 lying in the sectional plane A-A for the water is shown between inlet 4 and the interior of the cartridge 1 in the right-hand half of the cover 2.3. This passage is one of preferably two or more passages formed in the cover 2.3 around the outlet 5. These open out in a preferably circumferential recess 4.3, formed within the cover 2.3 and extending towards the neck, so that the inflowing water to be treated can be divided inside the water filter cartridge in the upper region thereof and can flow uniformly to the relevant flow sections or flow paths which are located downstream in the filter cartridge.

[0095] In this exemplary embodiment, these flow sections or flow paths are a main flow path 6 and a dosing flow path 7. Here, too, arrows 6.1 and 7.1 symbolize the flow direction of the water or of the relevant flow path.

[0096] The main flow path 6 extends in the upper quarter, referred to as granular material chamber 8, of the embodiment of a filter cartridge 1 shown here, in cross section over the entire area of the interior of the filter cartridge, except for the conduits arranged therein, the dosing pipe 7.2 for the dosing flow path 7 and the outlet pipe 5.2 for the outlet flow path 5.

[0097] The granular material chamber 8 is delimited downstream by a granular material chamber base 8.1. This granular material chamber base can comprise a nonwoven, a grille and/or the like. It retains granular material disposed in the granular material chamber 8.

[0098] The granular material functions in each of the two flow paths 6 and 7 as a resistance layer for water flowing through and is shown as an accumulation of granular material 6.3 in the main flow path 6 and of granular material 7.3 in the dosing flow path 7. The granular material/the resistance layer forms the resistance section 6.5 in the main flow 6 and the resistance section 7.5 in the dosing flow 7. Preferably, this is in each case the same granular material, which accordingly also has the same specific flow resistance and hence brings about the same differential pressure per cm in the direction of flow. This facilitates setting of a dosing ratio between the main flow 6 and the dosing flow 7 based on this differential pressure (see explanation in the general description part).

[0099] The water in this case flows from top to bottom through the granular material, i.e. the resistance section 6.5 of the main flow path 6 and the resistance section 7.5 of the dosing flow path 7.

[0100] A dosing chamber 9 in the form of a salt and brine vessel 9 is arranged downstream and below the granular material chamber 8 in the illustration in FIG. 2. This comprises an outer dosing chamber wall 9.1, a dosing chamber base 9.2, an inner dosing chamber wall 9.3 and a cover 9.4.

[0101] The dosing chamber 9 is designed as a hollow cylinder with an axial recess for the outlet pipe 5.2. It thus extends all around and on the left and right of the cartridge longitudinal axis 1.1 in the illustration in FIG. 2, the left and right side being joined to one another.

[0102] The dosing pipe 7.2 penetrates the granular material chamber base 8.1 and joins the granular material chamber 8 to the dosing chamber 9 through the dosing chamber cover 9.4.

[0103] Following the dosing pipe 7.2, a dosing conduit 9.5 leads in the direction of flow 7.1 from the dosing chamber cover 9.4 to the dosing chamber base 9.2 in order to allow the water flowing during operation of the filter cartridge 1 via the dosing section 7 to flow out from the dosing chamber 9 in the vicinity of the base.

[0104] The dosing chamber 9, which functions as a brine vessel 9 and which is also referred to as a storage vessel 9, contains salt 10. This salt is dissolved by water flowing through the filter cartridge during operation to form brine 11. The brine is then present as a concentrated salt solution 11 above the salt 10 in the dosing chamber 9 up to the lower side of the dosing chamber cover 9.4.

[0105] For the purposes of improved flow guidance in the dosing chamber 9 (cf. arrows 9.6) and in particular for removing the air therefrom, the dosing chamber cover 9.4 has an oblique design on its underside when viewed in cross section in the operational position of the filter cartridge, as shown in FIG. 2. The oblique cover of the dosing chamber 9 brings about easier migration of air bubbles, especially small air bubbles, towards the exit 9.7 of the dosing chamber.

[0106] This exit 9.7 is designed in the higher region of the dosing chamber 9 in the form of a passage out of the dosing chamber 9. In this embodiment, two exits are shown by way of example, one on the left and one on the right in the figure.

[0107] In a first embodiment, the exit 9.7 can function as a dosing point 9.8 for the concentrated salt solution 11 into the main flow 6. The brine mixes with the main flow 6 and flows along with it between the wall 2.1 of the housing 2 and the outer wall 9.1 of the dosing chamber, downwards in the illustration of FIG. 2 towards the outlet pipe 5.2 and onwards towards the outlet 5.

[0108] In order to ensure that the water treated by the filter cartridge 1 leaves the latter germ-free, it can be passed through an appropriate filter 12, for example an activated carbon filter. Such a filter is for example shown beneath the dosing chamber 9 in FIG. 2 as a further hollow cylindrical body. The centrally inner recess thereof opens into the outlet pipe 5.2.

[0109] According to a second, preferred embodiment, the exit 9.7 of the dosing chamber 9 can in contrast be connected to a further storage vessel 13 or temporary brine store 13 acting as a buffer. This temporary brine store 13 can for example be designed in the form of a hose, as illustrated in FIG. 3. This shows the illustration in the sectional plane B-B of FIG. 1, based on the embodiment according to FIG. 2, transversely through the filter cartridge 1 and rotated clockwise by 90 degrees.

[0110] The dosing points 9.8 for the brine 11 into the main flow 6 are in this case each exit 13.2 of each storage vessel 13 or temporary brine store 13 designed as a hose. This hose 13 lies in the form of a spiral in or on the sectional plane B-B. The connection 13.1 of the hose 13 passes through the granular material chamber base 8.1 into the dosing chamber 9, preferably at an angle.

[0111] This storage vessel 13 has the effect that in the event of stagnation, when the filter cartridge thus has no water passing through it, unintended pump processes cannot cause any over-concentration in the mineralization process, for example due to pressure fluctuations/pressure surges and/or escape of e.g. air in the system (see explanations above). Otherwise, identical references denote the same features as in the other figures.

[0112] FIG. 4 shows a further exemplary embodiment of a filter cartridge 1. Identical references here also denote the same features as in the preceding figures.

[0113] In contrast to FIG. 2, two dosing chambers are present in this design, a left one 9 and a right one 9′, each with an associated dosing pipe 7.2 and 7.2′, respectively. Each dosing chamber 9, 9′ can be filled with the same or, as shown by way of example, a different salt 10 or 10′ from the respective other dosing chamber 9′, 9. Accordingly, two identical, or, as shown here, two different brines 11 and 11′ are also formed.

[0114] The functional principle for the addition of minerals, that is to say of the respective brine 11 or 11′, into the main flow 6 can be realized as in the examples of FIGS. 2 and/or 3.

[0115] Here too, granular material layers are arranged in each case in the granular material chamber 8 and in the dosing pipes 7.2, 7.2′, these preferably being composed of the same granular material in order to establish the same resistance value per unit of distance.

[0116] The effective height 6.4 of the resistance/granular material layer 6.3 in the main flow 6 extends from the height of the inlet of the dosing pipe 7.3, 7.3′ to the granular material chamber base 8.1.

[0117] The effective height 7.4, 7.4′ of the resistance/granular material layer 7.3, 7.3′ in the respective dosing flow 7, 7′ likewise extends from the height of the inlet of the dosing pipe 7.3, 7.3′ concerned to the end of same, which in this case is located in the dosing chamber base 9.4.

[0118] The right-hand dosing pipe 7.2′ is by way of example dimensioned differently from the left-hand one. For example, a different dosing ratio between the left and right dosing flow could thus be brought about. For example for sulfate salt 10 on the left and for hydrogencarbonate salt 10′ on the right.

[0119] FIG. 5 shows, similar to FIG. 3, the illustration of a filter cartridge 1 in the sectional plane B-B of FIG. 1, but based on the embodiment according to FIG. 4, transversely through the filter cartridge 1 and rotated clockwise by 90 degrees.

[0120] In the lower half of the illustration here, the right-hand half of FIG. 4 is shown in plan view. The upper half here shows the left-hand half of FIG. 4. Here, too, identical references denote the same features as in the preceding figures, in particular as in FIG. 4.

[0121] FIGS. 6 to 8 show supplementary illustrations for better comprehension.

[0122] For instance, FIG. 6 likewise shows a longitudinal section through a filter cartridge 1 with housing 2. Here, too, identical item numbers denote the same features as in the other figures. Thus, for example, 6 denotes the main flow path, 7 and 7′ the dosing flow paths, 6.1, 7.1, 7.1′ the arrows for the directions of flow concerned. Items 9.7 and 9.7′ denote the two exits from the two dosing chambers 9, 9′ as dosing points for the addition of the brine into the main flow path 6, which can also be referred to as mixing point, and 10, 10′ the respective salt and 11, 11′ the associated brine or the brine supernatant. The inlet or feed into the dosing section is denoted with 7.2.1 and 7.2.1′.

[0123] Correspondingly, FIG. 7 shows, similarly to FIG. 4, the filter cartridge 1 with housing 2, main flow 6, dosing flow 7 and 7′ with effective height 6.4 of the resistance layer for the main flow 6 and effective height 7.4 for the dosing flow 7, 7′ and the respective cross-sectional area 6.2.2 for the main flow and 7.2.2 for the dosing flow. The granular material in the main flow is denoted with 6.3 and in the dosing flow with 7.3.

[0124] The brine dosing points are accordingly realized at the exits denoted with 9.7 and 9.7′ for a design with direct addition of brine from the brine chamber 9, in contrast to the designs according to FIGS. 3 and 5. That is to say, without a storage vessel 13 or temporary brine store 13.

[0125] FIG. 8 likewise shows a filter cartridge 1 with housing 2 in sectional illustration. This differs from the illustration in FIG. 7 essentially in that here a respective storage vessel 13 or temporary brine store 13 for the concentrated salt solution is provided in the form of a hose 13, corresponding to the embodiments according to FIGS. 3 and 5. The respective dosing point 9.8 concerned is here realized by the exit 13.2 or 13.2′ of the hose 13 or 13′.

[0126] FIGS. 9 and 10 schematically show by way of example two further embodiments with an internal structure which, compared to the designs operating in pressure mode according to FIG. 2 to 8, is modified to the extent that in these embodiments the water flows from bottom to top through the granular material layer, that is to say the resistance section 6.5 of the main flow path 6 and the resistance section 7.5 of the dosing flow path 7. They thus function based on the suction principle. Identical numbers each have the same meaning as in the previously described embodiments.

[0127] In detail, FIG. 9 shows a mains-fitted water filter cartridge 1 with a housing 2, comprising a wall 2.1, a base 2.2, a cover 2.3 and a neck 2.4.

[0128] Here, too, a bed of granular material 6.3 forms a resistance section 6.5 which, however, is arranged below/in a granular material chamber bell-shaped cover 8.3 such that, with the filter cartridge 1 in the operational orientation, with the outlet 5 directed upwards, the water flowing in according to the arrows 4.1 flows through it from bottom to top. This design operates on the basis of a suction principle.

[0129] The water 4.1 to be treated passes via inlets 8.1.3 in the dosing chamber base 8.1 into a distribution chamber 8.1.2 and from there, via a nonwoven and/or a grille 8.1.1 for retaining particles, into the granular material layer 6.3.

[0130] Only a small portion of the water 4.1 to be treated flows via the dosing flow 7. First downwards through a feed pipe 9.9 from the lower end of which it passes into the dosing chamber 9 storing the salt 10 and, by dissolving the salt 10, forms the brine 11 to be added to the main flow 6.

[0131] This brine 11 rises, according to the flow volume through the filter cartridge 1 and the dosing ratio between main and dosing flow, further upwards in the dosing chamber up to the cover thereof of dome-like design, and at the highest point thereof is sucked into the dosing pipe 7.2, which is arranged structurally above but formed functionally downstream of the dosing chamber 9, up to the brine dosing point 9.8.

[0132] The granular material 6.3 and 7.3 can in this design be a filter stage in the form of a bed of carbon, in particular activated carbon. In principle, however, other granular materials are also suitable for forming such a resistance section 6.5 and 7.5.

[0133] Air is removed from this filter cartridge substantially better and more rapidly compared to the embodiment in which the water flows through the granular material/resistance layer from the top. In particular when starting up, the air located in the salt vessel 9 between the salt grains can escape very rapidly through the dosing pipe 7.2 since the resistance of the dosing pipe for air is low compared to the resistance for water.

[0134] The brine solution 11 is dosed directly from the resistance pipe 7.2 of the dosing section 7 into the main flow 6 of the water to be treated.

[0135] Pressure fluctuations in the feed lead to movements in the amply dimensioned feed pipe 9.9 for the water, which yet becomes brine on flowing through the vessel.

[0136] The brine dosing itself remains virtually constant as a result of the suction principle, even in the event of external pressure fluctuations. In the event of pressure fluctuations in the feed, as arise during the depressurization of the whole filter 1, for example when the water pressure upstream of the filter drops from 2 bar to 1 bar when a tap is opened and the bubbles expand, the enclosed air bubbles in the salt vessel 9 expand. These air bubbles displace only little saturated brine towards the outlet via the dosing pipe which is filled with granular material and through which flow is difficult, whereas in contrast most brine flows back into the large downpipe and does not cause any increase in the salt load in the mineralized water.

[0137] FIG. 10 shows a similar embodiment as FIG. 9, but with two brine dosing devices, as an example for a plurality of possible.

[0138] The modes of operation are the same, and therefore identical item numbers also have the same meaning as set out with respect to FIG. 9. Thus, for reasons of simplification, reference is made in principle to the above explanations with respect to FIG. 9.

[0139] Hereinafter, only the items concerning the additionally illustrated elements of the second dosing device are accordingly described. The numbers of the elements concerned of the second brine dosing device are supplemented with “′” in this case.

[0140] This design comprises two dosing chambers 9, 9′ which each contain salt 10, 10′ and brine 11, 11′. These brines are added into the main flow 6 of the water to be treated via the two dosing pipes 7.2, 7.2′ at the respective brine dosing points 9.8, 9.8′. The salts are preferably different in order for example to be able to add two different minerals. The dosing ratios may also be different, for example depending on the respective desired amounts of the particular salt that are to be added.

LIST OF REFERENCES

[0141] 1 Filter cartridge [0142] 1.1 Cartridge longitudinal axis [0143] 2 Housing [0144] 2.1 Wall [0145] 2.2 Base [0146] 2.3 Cover [0147] 2.4 Neck [0148] 2.4.1 Fastening elements [0149] 2.4.2 Outer wall [0150] 3 Protective cap [0151] 4 Inlet [0152] 4.1 Arrow [0153] 4.2 Passage [0154] 4.3 Recess [0155] 5 Outlet [0156] 5.1 Arrow [0157] 5.2 Outlet pipe [0158] 6 Main flow path [0159] 6.1 Arrow [0160] 6.2.2 Cross-sectional area of main flow [0161] 6.3 Granular material [0162] 6.4 Effective height of the resistance/granular material layer [0163] 6.5 Resistance section [0164] 7 Dosing flow path [0165] 7.1 Arrow [0166] 7.2 Dosing pipe [0167] 7.2.1 Feed/inlet into the dosing pipe [0168] 7.2.2 Cross-sectional area of the dosing flow [0169] 7.3 Granular material [0170] 7.4 Effective height of the resistance/granular material layer [0171] 7.5 Resistance section [0172] 8 Granular material chamber [0173] 8.1.1 Nonwoven and/or grille [0174] 8.1 Granular material chamber base [0175] 8.2 Granular material chamber bell-shaped cover [0176] 8.3 Retaining means [0177] 9 Dosing chamber (also referred to as brine or storage vessel) [0178] 9.1 Dosing chamber wall [0179] 9.2 Dosing chamber base [0180] 9.3 Dosing chamber wall [0181] 9.4 Dosing chamber cover [0182] 9.5 Dosing conduit [0183] 9.6 Arrow [0184] 9.7 Exit [0185] 9.8 Dosing point for salt solution [0186] 9.9 Feed pipe [0187] 10 Salt [0188] 11 Brine [0189] 12 Filter [0190] 13 Storage vessel [0191] 13.1 Connection [0192] 13.2 Exit