WATER HARDNESS STABILIZATION WITH ANION EXCHANGER

Abstract

The invention relates to a solid dosing agent for dosing phosphate and/or polyphosphate in water. This is characterized by the provision of a water-insoluble anion exchanger that is at least partially loaded with orthophosphate and/or polyphosphate counterions.

This achieves both long-lasting stable storage of the polyphosphate and good dosing of polyphosphate in water.

Claims

1. A solid dosing composition for dosing phosphate and/or polyphosphate in water comprising a water-insoluble anion exchanger containing orthophosphate and/or polyphosphate counterions.

2. The solid dosing composition for dosing phosphate and/or polyphosphate in water as claimed in claim 1 wherein the water-insoluble anion exchanger is a basic anion exchanger.

3. The solid dosing composition for dosing phosphate and/or polyphosphate in water as claimed in claim 1 wherein the water insoluble anion exchanger includes polystyrene.

4. The solid dosing composition for dosing phosphate and/or polyphosphate in water as claimed in claim 1 wherein the water-insoluble anion exchanger includes polyacrylate.

5. A process for producing a solid dosing composition for dosing phosphate and/or polyphosphate in water comprising forming a water-insoluble anion exchanger having orthophosphate and/or polyphosphate counterions by first using a liquid polyphosphate solution as starting material for loading water insoluble anion exchanger.

6. The process for producing a solid dosing composition for dosing phosphate and/or polyphosphate in water as claimed in claim 5 further comprising the step of first filtering the polyphosphate solution through an acidic cation exchanger and then passing it through the anion exchanger in OH.sup./free base form.

7. The use of the product of the process of claim 15 for stabilizing water hardness.

8. The use of the product of the process of claim 15 in a water filter device.

9. The use of the product of the process of claim 15 in a water tank of an appliance.

10. The use of the product of the process of claim 15 to prevent deposits from forming on surfaces in a water tank that come into contact with water.

11. The use of the product of the process of claim 15 in a water filter device for a mains-fitted water filter device.

12. The solid dosing composition for dosing phosphate or polyphosphate as claimed in claim 1 wherein the water-insoluble anion exchanger is a weakly basic anion exchanger.

13. The process for producing a solid dosing composition for dosing phosphate and/or polyphosphate in water of claim 6 wherein the liquid phosphate solution is a solution of sodium polyphosphate.

14. The process for producing a solid dosing composition for dosing phosphate and/or polyphosphate in water of claim 13 wherein said acidic cation exchanger is a strongly acidic cation exchanger.

15. The product of the process of claim 5.

16. The use of the product of the process of claim 15 in a water tank of a hot beverage machine.

17. The use of the product of the process of claim 15 in a household appliance.

18. A stable storable water-insoluble anion exchanger composition with a controlled polyphosphate release in water comprising a water insoluble anion resin, a phosphate or a polyphosphate and an orthophosphate and/or polyphate counterions.

19. The stable storable water-insoluble anion exchanger composition of claim 18 wherein the water insoluble anion resin is a polystyrene anion exchange resin.

20. The stable storable water-insoluble anion exchanger composition of claim 18 wherein the water-insoluble anion resin is a polyacrylate anion exchange resin.

Description

WORKING EXAMPLE

[0046] The present invention is elucidated in more detail hereinbelow with reference to the included figures and the description that refers to them.

[0047] In the figures:

[0048] FIG. 1 shows the formulas for the production of a polyphosphate-loaded anion exchanger for dosing polyphosphate in water.

[0049] FIG. 2 shows an exemplary diagram of the steps in the production process for a polyphosphate-loaded anion exchanger for dosing polyphosphate in water and of the products and intermediates that are used and formed in the process.

[0050] FIG. 3 shows the formulas for the use of a polyphosphate-loaded anion exchanger for dosing polyphosphate in water.

[0051] FIG. 4 shows an exemplary diagram, in longitudinal cross section, of a water filter cartridge containing an agent for preventing the formation of limescale in water, when used in a water tank likewise shown in longitudinal cross section.

[0052] FIG. 5 shows an exemplary diagram, in front view, of an alternative embodiment to FIG. 4 comprising a water filter cartridge having a reservoir for an agent countering the formation of limescale.

[0053] FIG. 6 shows an exemplary diagram, in sectional view, of the embodiment presented in FIG. 5.

[0054] FIG. 7 shows an exemplary diagram, in longitudinal cross section, of a mains-fitted water filter cartridge containing an agent for preventing the formation of limescale in water.

CONSTRUCTIONAL DESIGN

[0055] FIG. 1 shows formulas 1.) and 2.) for the production of a polyphosphate-loaded anion exchanger for dosing polyphosphate in water. In the figure:

Na.SUP.+.: Sodium ion

[0056] [H.sub.2PO.sub.4.sup.].sub.N: Polyphosphate ion having
chain length .sub.N and .sub.N negative charges
[H.sub.3PO.sub.4].sub.N: Polyphosphoric acid
R.sup.: Strongly acidic cation exchanger
R.sup.+: At least weakly basic anion exchanger

H.SUP.+.: Hydrogen ion

OH.SUP..: Hydroxide ion

[0057] Step 1: Removal of Sodium

.sub.N.Na.sup.++[H.sub.2PO.sub.4.sup.].sub.N+.sub.N.[R.sup.H.sup.+].sub.N.[R.sup.Na.sup.+]+[H.sub.3PO.sub.4].sub.N

[0058] Step 2: Bonding of Polyphosphate on Anion Exchanger

.sub.N.[R.sup.+OH.sup.]+[H.sub.3PO.sub.4].sub.N.sub.N. R.sup.+[H.sub.2PO.sub.4.sup.].sub.N+.sub.N.H.sub.2O

[0059] FIG. 2 shows an assembly 20 for producing an anion exchanger loaded with polyphosphate 21 for dosing polyphosphate in water in accordance with formulas 1.) and 2.) shown in FIG. 1.

[0060] In process step 1.), the anion exchanger is loaded with polyphosphate ions by first filtering the sodium polyphosphate solution 21 through a preferably strongly acidic cation exchanger 23 and then passing it through the anion exchanger 24 in accordance with process step 2.) The latter may be present, for example, in at least weakly basic OH.sup./free base form.

[0061] In the assembly 20 shown by way of example, the sodium polyphosphate solution 21 held in container 21.1 is passed in the direction of arrow 21.2 onto the strongly acidic ion exchanger granules 23 in H.sup.+ form in a container 22 in order to separate the polyphosphate from the sodium, and is then fed, via the outlet 22.1, onto the support material in container 25, which is in the form of anion exchanger granules 24, in order to load the latter with polyphosphate.

[0062] Residual demineralized water 27 is run off into a container 26 through the outlet 25.1, which is provided with a means of closure 25.2.

[0063] The polyphosphate that is now ionically bonded to the anion exchanger granules 24 has almost limitless storage stability and is stable under both dry and wet conditions.

[0064] FIG. 3 shows the formula for the release of polyphosphate from the anion exchanger loaded according to the process shown in FIG. 2, for dosing polyphosphate in water.

[0065] In the figure: [0066] R.sup.+.sub.N: Weakly basic anion exchanger [0067] [H.sub.2PO.sub.4.sup.].sub.N: Polyphosphate having chain length N and N negative charges [0068] HCO.sub.3.sup.: Hydrogen carbonate

R.sup.+.sub.N.[H.sub.2PO.sub.4.sup.].sub.N+.sub.N.[HCO.sub.3.sup.]R.sup.+.sub.N.[HCO.sub.3.sup.]+[H.sub.2PO.sub.4.sup.].sub.N

[0069] The release of polyphosphate in contact with water is kept within an upper limit through ion-exchange equilibria reactions with substances present in the water. Below the equilibrium with untreated water, the rate of release is, by contrast, high. This allows sufficient release of polyphosphate over a long period.

[0070] This process for stabilizing hardness thus uses an anion exchanger having polyphosphate counterions for dosing polyphosphate in water. This is preferably a weakly basic polyacrylate-based anion exchanger. Alternatively, a weakly basic polystyrene-based anion exchanger may be used.

[0071] The starting material for the polyphosphate anion used is a liquid polyphosphate solution, in particular a sodium polyphosphate solution. Potassium polyphosphate solutions are also conceivable.

[0072] The anion exchanger is loaded with polyphosphate ions by first filtering the sodium polyphosphate solution through a preferably strongly acidic cation exchanger and then passing it through the anion exchanger in OH.sup./free base form.

[0073] FIG. 4 shows a water filter cartridge 1 containing an anion exchanger having polyphosphate counterions for dosing polyphosphate in water, when used in a water tank 10, the housing of which is numbered 10.1. For this, the filter-side tank connection element 3 is coupled to a tank-side filter connection element 10.2, preferably by means of a plug-in connection.

[0074] The water filter cartridge 1 comprises a housing 2, an inlet opening 1.3 and an outlet opening 1.4 for the inflow and outflow of the water 8 held in the water tank into the filter cartridge 1 and back out again. For use in, for example, a hot-beverages machine 11 connected downstream, this water 8 is treated by passage through a filter train 4. Such a filter train may be designed in the upflow chamber 1.1 and/or the downflow chamber 1.2. The arrows 8.1 indicate the direction of flow of the water during the withdrawal thereof from the water tank 10 when the filter cartridge 1 in the fully operational state is in operation as a filter.

[0075] The water filter cartridge 1 comprises, in addition to the filter train 4 and designed separately therefrom, a reservoir 6, preferably in the form of a storage tank for an antiscaling agent 5, in particular an agent countering the formation of limescale in the water tank, with contact openings 7 provided that connect the reservoir 6 with the water 8 held in the water tank 10.

[0076] The reservoir 6 may be positioned in the housing 2 of the water filter cartridge 1; in the illustrated case in a top unit 2.1 of the housing.

[0077] The agent 5 countering the formation of limescale in the water tank may include a weakly acidic cation exchanger and/or a hardness stabilizer and/or a poorly soluble polyphosphate, in particular one that is calcium-based.

[0078] The agent 5 countering the formation of limescale in the water tank may include a freely soluble polyphosphate that is sodium-based.

[0079] In addition, the agent 5 countering the formation of limescale in the water tank may include a weakly basic anion exchanger material, in particular a weakly basic anion exchanger material having polyphosphate ions as counterions.

[0080] And the weakly basic anion exchanger material may be provided as a stabilizing agent for the polyphosphate.

[0081] The arrows 8.1 indicate the inflow of the water 8 held in the water tank 10 into the agent 5 countering the formation of limescale in the water tank. It flows through the contact openings 7 into the reservoir for the agent 5. A casing 9 or the like is optionally also provided to additionally enclose the agent 5.

[0082] The arrows 5.1 indicate the water 8 held in the water tank 10 that has already been treated with the agent 5 countering the formation of limescale in the water tank. Because the treatment substances from the agent 5 are in higher concentration in the water 8 close to the agent 5 compared to water held elsewhere in the water tank but which has not yet come into contact with the agent 5, a concentration equilibrium develops that, over the course of the storage period, also effects treatment of the remaining water stored in the water tank and thereby, in accordance with the invention, prevents the formation of limescale on the surfaces coming into contact with the water.

[0083] An agent 5 countering the formation of limescale, in the form of a hardness stabilizer, may also additionally be provided in the area through which the water undergoing treatment passes in and/or around the water filter cartridge 1. For example in and/or around the area of water inflow into the filter cartridge. A reservoir 6 therefor may also be provided, for example, in the form of a space at least partially enclosed by a fabric, for example, an insert component such as a ring filled with the agent 5, or in the form of a filling, preferably at least outwardly secured with a means of preventing the contents from escaping, for example a casing or the like. As an example thereof, a reservoir 6 filled with an agent 5 is shown above the inlet opening 1.3 in FIG. 4.

[0084] FIG. 5 shows an exemplary diagram, in front view, of an alternative embodiment to FIG. 4 comprising a water filter cartridge 1 having a reservoir 6 for an agent 5 countering the formation of limescale. In this embodiment, a reservoir 6 for the agent 5 countering the formation of limescale may be positioned in and/or on the housing 2. Small circles are depicted for visualization of the preferably granular agent 5. The granules 5 may be held inside the reservoir 6 by means of a cover, for example corresponding to the top unit 2.1 in the design shown in FIG. 4. Here too, contact openings 7 may provide the water with access to the agent 5. The rectangular representation of the contact openings 7 is shown purely by way of example for easier differentiation in this visualization. They can also have other shapes and/or cross sections.

[0085] FIG. 6 shows a sectional view of the design for a water filter cartridge 1 shown in FIG. 5 that has, on opposite sides of the housing 2, reservoirs 6 for the agent 5 countering the formation of limescale. To simplify the illustration, contact openings 7 water with access to the agent 5 are not shown, but may be present. The remaining reference numbers correspond to the features of the water filter cartridge 1 presented in FIG. 1.

[0086] FIG. 7 shows a further use in which a mains-fitted water filter canister 30 contains an agent 5 countering the formation of limescale, which is preferably stored inside a reservoir 6. The mains-fitted water filter canister 30 is connected to a connection head 31 that is connected to an inflow line 32 and an outflow line 33 of a water line. Arrows 34 indicate the direction of flow of the water.

LIST OF REFERENCE NUMBERS

[0087] 1 Water filter cartridge [0088] 1.1 Upflow chamber [0089] 1.2 Downflow chamber [0090] 1.3 Inlet opening [0091] 1.4 Outlet opening [0092] 2 Housing [0093] 2.1 Top unit [0094] 3 Filter-side tank connection element [0095] 4 Filter train [0096] 5 Agent countering the formation of limescale [0097] 5.1 Water treated with the agent countering the formation of limescale [0098] 6 Reservoir [0099] 7 Contact openings [0100] 8 Water [0101] 8.1 Arrow [0102] 9 Casing or the like [0103] 10 Water tank [0104] 10.1 Housing [0105] 10.2 Tank-side filter connection element [0106] 11 Household appliance, in particular hot-beverages machine [0107] 20 Assembly [0108] 21 Polyphosphate [0109] 21.1 Container [0110] 21.2 Arrow [0111] 22 Container [0112] 22.1 Outlet [0113] 23 Cation exchanger [0114] 24 Anion exchanger [0115] 25 Container [0116] 25.1 Outlet [0117] 25.2 Means of closure [0118] 26 Container [0119] 27 Demineralized water [0120] 30 Mains-fitted water filter canister [0121] 31 Mains-fitted connection head for 30 [0122] 32 Inflow line [0123] 33 Outflow line [0124] 34 Arrow