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Title:
AUTONOMOUS LIQUID DOSING SYSTEM
Document Type and Number:
WIPO Patent Application WO/2021/070172
Kind Code:
A1
Abstract:
A method and a system for fortifying water with an aqueous solution containing one or more minerals or beneficial additives is described. The system provides accurate dosing without the need for an electrical connection. The system contains a flexible container holding the fortifying solution which is situated in contact with an external container through which water flows to a tap. Flow of the water from the water supply to the tap compresses the flexible container and forces a flow of the fortifying solution out of the flexible container. Check valves are installed to prevent backflow.

Inventors:
BROWN GAL (IL)
Application Number:
PCT/IL2020/051012
Publication Date:
April 15, 2021
Filing Date:
September 16, 2020
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
BROWN GAL (IL)
International Classes:
C02F1/68; A23L33/10; A23L33/16; A61J1/20
Foreign References:
US20100270399A12010-10-28
EP0036307A21981-09-23
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Claims:
CLAIMS

1. A system for adding a quantity of a chemical to a water stream, the system comprising: a rigid container through which the water stream flows; a flexible container containing a solution of the chemical, the flexible container disposed within the rigid container such that pressure from the water stream compresses the flexible container thus expelling a portion of the solution from the flexible container; and a mixing chamber having a first inlet connected to the flexible container, a second inlet connected to the rigid container, and an outlet.

2. The system according to claim 1, wherein the rigid container is a polyvinylchloride tube.

3. The system according to claim 1 or 2, wherein the flexible container is a silicone tube.

4. The system according to claim 1 or 2, wherein the flexible container is an aluminum bag.

5. The system according to any one of claims 1 to 4, further comprising a flowmeter.

6. The system according to any one of claims 1 to 5, further comprising a pressure gauge.

7. The system according to any one of claims 1 to 6, further comprising an inlet pressure regulator.

8. The system according to any one of claims 1 to 7, further comprising an ion exchange column.

9. The system according to any one of claims 1 to 8, further comprising a column of activated carbon or beta alumina.

10. The system according to any one of claims 1 to 9, wherein said outlet is connected to a water tap.

11. The system according to claim 10, wherein said water tap includes a first tap for dispensing water from said outlet and a second tap for dispensing water from said water stream.

12. The system according to claim 10 or 11, further including a mixer for mixing water from said outlet with said water stream.

13. The system according to any one of claims 1 to 12, wherein the water stream is for human consumption.

14. The system according to claim 13, wherein the chemical is a vitamin or mineral.

15. The system according to claim 14, wherein the chemical is magnesium.

16. The system according to claim 15, wherein the magnesium is in the form of magnesium chloride or magnesium sulfate.

17. The system according to claim 16, wherein the magnesium is in the form of magnesium chloride.

18. The system according to any one of claims 1 to 12, wherein the water stream is for animal consumption.

19. The system according to claim 18, wherein the chemical is a vitamin, mineral or medicine.

20. The system according to claim 19, wherein the medicine is an antibiotic.

21. The system according to any one of claims 1 to 12, wherein the water stream is for agricultural use.

22. The system according to claim 21, wherein the chemical is an ammonium compound, a phosphate, a pesticide or an herbicide.

23. The system according to any one of claims 1 to 22, wherein said solution comprises a disinfectant.

24. The system according to claim 23, wherein said disinfectant is active chlorine or hydrogen peroxide.

25. The system according to any one of claims 1 to 24, wherein the flexible container is connected to the first inlet via a microtube.

26. The system according to any one of claims 1 to 24, wherein the flexible container contains a flow adjusting element to control the flow of the solution out of the flexible container.

27. The system according to claim 26 wherein the flow adjusting element is a screw.

28. The system according to claim 26 wherein the flow adjusting element is a smart faucet that can be controlled remotely by WiFi or Bluetooth.

Description:
AUTONOMOUS LIQUID DOSING SYSTEM

FIELD OF THE INVENTION

The invention pertains to the fields of chemical and/or medicine dosing and water treatment. More particularly, the invention pertains to adding a beneficial compound to drinking water or any water consumed by humans, animals or plants, especially for dosing beneficial chemicals (e.g. mineral salts, including ions of magnesium, iodine, potassium and fluoride, vitamins, such as ascorbic acid and vitamin B12, and beneficial food additives such as citric acid, etc.) in low rates to small water systems, (e.g. to a water tap in a residence, office, or factory) or to the main water inlet of a residential unit, building or irrigation system.

BACKGROUND OF THE INVENTION

Over the last half century, desalination systems have been increasingly used for drinking water supply. The desalinated water is deficient in many beneficial minerals that are important or deemed essential or beneficial for consumers’ health. However, in many cases the water suppliers do not fortify the water with important minerals that were removed by desalination, and many households wish to install a simple dosing device to fortify the tap water with a small amount of the deficient minerals while still assuring that the level of the fortified ingredients will be carefully controlled and will not be excessive.

A remineralization system can be a beneficial addition not just to desalinated water sources, but to any water source with nutrient deficiencies (e.g. surface water after treatment). The very same system can be used to fortify household water supplies with important nutrients or small irrigation systems with dissolved pesticides or nutrients, including, for example, magnesium, phosphorous and nitrogen containing species. The system can also be implemented in animal drinking water systems.

Despite the success of small domestic water filtration systems that can be connected to the supply pipe of an individual consumer, dosing systems for the enrichment of the drinking water with minerals are not available to consumer households. In particular, fortifying systems that are suitable for installation under the kitchen sink (without the need for a professional plumber) or combined systems that can fortify the water with some chemicals are still unavailable. Likewise, a system combining supply of nutrients and removal of excessive concentrations of undesirable ingredients under said conditions are still unavailable. An additional challenge is to provide a chemical fortifying system that can operate autonomously and fortify the water with desirable chemicals without specific manual intervention.

Large systems for the treatment of the drinking water of a neighborhood, village or a whole city are routinely used, but those systems require constant electrical supply as well as extensive maintenance and involve significant capital investment. Furthermore, their principle of operation and operating conditions deviate significantly from those required for domestic mineral fortification units to the point that they are irrelevant. Water dosing systems consist of a tank or another water reservoir with a solution to be added to the water. The dosage to the water is usually done by pumps which require an external power source (e.g. an electro-mechanical, centrifugal, peristaltic or diaphragm pump) or by a venturi pump that operates on the Bernoulli principle. Conventional water dosing systems used in water treatment (i.e. systems that add chemicals such as fluoride and chlorine to drinking water in the water treatment industry, and chemical dosing systems in the food industry) are powered by electricity, and thus require an electrical connection close to the system installation area. An electrical dosing system is more likely to malfunction, and locating an electrically powered system under a kitchen sink is inconvenient and often unfeasible, particularly in less developed countries. Although a venturi pump does not require external power, venturi dosage is not accurate and dosing depends very much on the pressure in the distribution system or the boundary condition (such as the water speed) in the venturi pump.

Thus, there is an unmet need for a simple system that can fortify domestic water with a controlled dose of minerals containing ions such as magnesium, potassium, iodine or food additives. The supply of controlled doses of magnesium can be achieved by adding magnesium salts, and, in particular, solutions of magnesium carbonate or magnesium bicarbonate from a CO2 pressurized system. Such systems are described in US 2005/0255174, WO 2011/045795 and WO 2015/091566. To achieve high concentrations of magnesium it is necessary to provide high pressure of carbon dioxide or use supersaturated solutions and recirculation loops. The obtained solutions are not stable during extended storage times at ambient temperature due to the quick formation of carbonate precipitate. Whereas such systems may be used for public utilities, they are impractical for individual households which cannot afford the capital cost and maintenance involved in high pressure magnesium carbonate or magnesium bicarbonate dosing.

To date there is no low-cost system that can be used to dose minute and controlled amounts of magnesium solution to a drinking water tap. This invention provides dosing of magnesium chloride without using a pressurized system, oversaturated solutions, additional pumping systems, electric power or a venturi suction pump. Feeding the fortifying solution into the water stream can be done at the pressure of the water distribution system.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a system for adding a quantity of a chemical to a water stream, the system comprising: a rigid container through which the water stream flows; a flexible container containing a solution of the chemical, the flexible container disposed within the rigid container such that pressure from the water stream compresses the flexible container thus expelling a portion of the solution from the flexible container; and a mixing chamber having a first inlet connected to the flexible container, a second inlet connected to the rigid container, and an outlet.

Preferably, the rigid container is a polyvinylchloride tube. In one embodiment, the flexible container is a silicone tube. In alternative embodiment, the flexible container is an aluminum bag.

In one embodiment, the system additionally includes one or more of the following components: a flowmeter, a pressure gauge, an inlet pressure regulator, an ion exchange column, a column of activated carbon or beta alumina.

In one embodiment, the outlet is connected to a water tap. The water tap preferably includes a first tap for dispensing water from said outlet and a second tap for dispensing water from said water stream. In one embodiment the system includes a mixer for mixing water from said outlet with said water stream.

In one embodiment, the water stream is for human consumption. The chemical may be a vitamin or mineral. Preferably, the chemical is magnesium. In one embodiment, the magnesium is in the form of magnesium chloride or magnesium sulfate, most preferably, magnesium chloride.

In an alternative embodiment, the water stream is for animal consumption. Preferably, the chemical is a vitamin, mineral or medicine, such as antibiotic. In a further alternative embodiment, the water stream is for agricultural use. Preferably, the chemical is an ammonium compound, a phosphate, a pesticide or an herbicide. In all of the embodiments, the solution may comprise a disinfectant such as active chlorine or hydrogen peroxide.

In one preferred embodiment the flexible container is connected to the first inlet via a microtube. In an alternative preferred embodiment, the flexible container contains a flow adjusting element to control the flow of the solution out of the flexible container. The the flow adjusting element is a preferably a screw. Alternatively, the flow adjusting element may be smart faucet that can be controlled remotely by WiFi or Bluetooth. BRIEF DESCRIPTION OF THE DRAWING

The present invention will now be described by way of example with reference to the accompanying drawings wherein: Fig. 1 is a perspective view of a dosing system in accordance with an embodiment of the present invention;

Fig. 2 is another perspective view of a dosing system in accordance with an embodiment of the present invention;

Fig. 3 is a cross-sectional view along the axis of a dosing system in accordance with an embodiment of the present invention;

Fig. 4 is a cross-sectional view along the axis of a dosing system in accordance with an embodiment of the present invention showing the flow of different solutions in the dosing system;

Fig. 5 is an isometric view of an outlet end of a dosing system in accordance with an embodiment of the present invention;

Fig. 6 is a simplified schematic of a nutrient fortification system in accordance with an embodiment of the present invention; and

Fig. 7 is a simplified schematic the flow of water from a nutrient fortification system in accordance with an embodiment of the present invention to a domestic water tap.

DETAILED DESCRIPTION OF THE INVENTION

With reference to Fig. 1, a dosing unit 10 is shown. Dosing unit 10 comprises a main tube 12 having an inlet cup 14 and an inlet port 16 for connecting to the domestic water supply. Main tube 12 may be a standard polyvinylchloride (PVC) tube. Inlet port 16 can be any standard hose fast connection made of plastic or stainless steel such as Lergis series LF3000. Main tube 12 also comprises an outlet cup 18 with an outlet cup cover 20. Outlet cup 18 includes an inner mixing compartment for mixing of a fortifying nutrient solution with the water from the water supply flowing to the tap, which will be described below with reference to Fig. 3. Dosing unit 10 does not include any electrical connector and is operational as long as the pressure at the inlet of dosing unit 10 is at least 2 bar, preferably between 2 and 3 bar, most preferably about 2.5 bar. Main tube 12 preferably has a diameter of 20-100 mm and a length of 150-750 mm. However, the size of main tube 12 is not limited to these values and can be larger or smaller as well.

Reference is now made to Fig. 2 which is a perspective view of dosing unit 10 from the side of outlet cup 18. Outlet cup cover 20 includes an outlet port 22 through which water fortified with the nutrient flows to a tap. Outlet cup 18 and outlet cup cover 20 are preferably made of PVC. Outlet port 22 is preferably made of plastic or stainless steel such as Lergis series LF3000

Fig. 3 shows a cross section along the longitudinal axis of dosing system 10 shown in Figs. 1 and 2. In the interior of main tube 12, inlet port 16 is preferably coupled to an inlet non-return valve system to prevent leakage of the nutrient solution back to the water supply and to stop the fortification of the nutrient to the water when the flow to the tap stops. The non-return valve system preferably includes a flow accessory tube 24 to prevent back-flow of water from main tube 12 out though inlet port 16 in case of pressure loss in the water supply to dosing system 10. Flow accessory tube 24, which may be a PVC tube, includes a flexible portion 26 that allows flow only in one direction. Flexible portion 26 may be made of silicone or another elastic polymer, or may be a mechanical non-return valve (NRV). In a preferred embodiment, water flows through an inlet tube 28 and lifts up flexible portion 26, allowing water to flow to the interior of main tube 12. When the flow to the tap stops, flexible portion 26 shrinks back on flow accessory tube 24 and seals it, preventing water from flowing backward. Main tube 12 includes in its interior a flexible inner container 30 filled with a fortifying nutrient solution. Flexible inner container 30 is preferably made from silicone or another elastic polymer or aluminum compliant with drinking water or other water end-use requirements. In one embodiment, flexible inner container 30 may be a standard silicone tube. In another embodiment, flexible inner container 30 is an aluminum bag. The diameter of the flexible inner container 30 is preferably in the range of 15 mm to 80 mm, but it can have a smaller or larger diameter. In one embodiment, the diameter of flexible inner container 30 is about 40 mm. Flexible inner container 30 is smaller than main tube 12, preferably having a volume of 60-90% of the volume of main tube 12. A size that is too small will lower the amount of the nutrient held within, and a size that is too large can cause flexible inner container 30 to cling to main tube 12. Flexible inner container 30 is preferably a round tube with one end closed and the other end open for coupling to outlet cup 18.

When the entire volume of main tube 12 fills with water, flexible inner container 30 is compressed thus pushing out fortifying nutrient solution to a channel 32 via borehole 34. The amount of fortifying nutrient solution that exits flexible inner container 30 depends, inter alia, on the pressure in main tube 12 and the diameter of channel 32. In one embodiment, channel 32 is a microtube. The diameter of the microtube can be in the range of 0.1 mm- 1.5 mm, preferably about 0.5 mm, and the length can be in the range of 5 mm to 200 mm, preferably about 10 mm. The head loss caused by the small diameter of the microtube results in a limited flow of fortifying nutrient solution from flexible inner container 30 in order to achieve the desired dilution ratio.

In an alternative embodiment, flexible inner container includes a flow adjusting element 36 which controls the flow of the fortifying nutrient solution into channel 32. Flow adjusting element 36 can be in the form of an adjusting screw made of e.g. stainless steel, titanium or plastic. The adjusting screw constricts channel 32 from flexible inner container 30 to the mixing volume where the fortifying and fortified water streams are mixed. Preferably, the adjusting screw is not visible to the end consumer and can be adjusted only by a technician. Alternatively, flow adjusting element 36 is a smart faucet which can be controlled remotely by Wi-Fi or Bluetooth.

Channel 32 includes a no-retum valve 38 to prevent flow of water back into flexible inner container 30 and dilution of the fortifying nutrient solution. The fortifying nutrient solution flows through valve 38 to a mixing chamber 40. Water from main tube 12 flows through a channel 42 to mixing chamber 40 and is mixed with the fortifying nutrient solution. Channel 42 includes a no-return valve 43 to prevent back flow into main tube 12. The solution from the mixing chamber flows out of dosing unit 10 to a tap through outlet port 22. Alternatively, the solution flowing from outlet port 22 may be mixed with water from the water supply flowing in parallel to the water in dosing unit 10 as another means to control the mixing ratio of the fortifying nutrient solution and the water.

Fig. 4 shows the flow of the water from the water supply, the fortifying nutrient solution and the fortified water in dosing system 10. The blue dashed line shows the flow of water from the water supply. The red arrows show the flow of the fortifying nutrient solution. The dark blue triangles show the flow of the fortified water. Fig. 5 is an isometric view of the outlet end of dosing system 10. The connections between channel 32 which provides the fortifying nutrient solution and channel 42 which provides water from main tube 12 with mixing chamber 40 can be seen in Fig. 5.

Typically, a used flexible inner container 30 will be replaced by a new, full one or refilled after its content drops below approximately 10% of its initial volume. Flexible inner container 30 may contain only one nutrient or several nutrients. The concentration of the nutrients should be set to such a concentration that after dilution with water coming from the water supply their concentration in mg/L times 2 liters will provide equal to or less than the daily recommended consumption of each nutrient.

The concentration of each of the nutrients should not exceed the solubility limit under the anticipated working temperature (e.g. between 0 and 60 °C or between 0 and 40 °C) unless solubilization of the nutrients and formation of a stable aqueous microemulsion is attained.

The water supply may be a domestic water supply for providing water for human consumption in residential, commercial or industrial areas. The water supply may be for farming use, such as for consumption by livestock and poultry. Alternatively, the water supply may be for agricultural use, such as for irrigation.

Examples of nutrients and their concentration range include minerals such as magnesium salts having a concentration of 1 g/L to 75 g/L, preferably 5 g/L to 15 g/L, as magnesium; water soluble vitamins including vitamin Bl, B2, B4, B5, B6, and B12 at concentrations below 0.5 g/L each; vitamin B3 at a concentration of up to 10 g/L; vitamin C at a concentration up to 30 g/L; iodide at a concentration of up to 75 mg/L; and fluoride at a concentration of up to 1 g/L. The solution can also contain a disinfectant such as active chlorine (in the form of hypochlorite salt) at a concentration of up to 4 mg/L or hydrogen peroxide at a concentration lower than 30 mg/L to prevent microorganism growth in the flexible container. However, the concentration range is not limited to these values and can be higher or lower as well.

The magnesium salt can be magnesium chloride, magnesium sulfate, magnesium bicarbonate or magnesium nitrate at a concentration that will not exceed, after dilution, the maximum allowable concentration in drinking water. More preferably, the magnesium salt is magnesium chloride or magnesium sulfate. Most preferably, the magnesium salt is magnesium chloride.

The dilution ratio of the nutrient coming from the flexible container and water coming from the tap should be between 1:50 to 1:10000, more preferably between 1:50 and 1:1000, most preferably from 1:50 to 1:500. The dilution ratio depends on the dilution requirements in each field of use, with higher dilution for agriculture and lower dilution for medical applications. However, the dilution ratio is not limited to these values and can be higher or lower as well.

For agricultural use, flexible inner container 30 may contain a phosphorous source (e.g. a phosphate salt) or a nitrogen source (e.g. nitrate, ammonia or urea) at a concentration which is below the solubility limit.

A combination of one, several or all of the abovementioned nutrients can be used. For example, a desirable combination of two or more compounds selected from the group consisting of citric acid, ascorbic acid, folic acid, a vitamin B mineral, and acidity regulators (such as acetic acid or carbonates). For agriculture uses, a combination of nutrients (e.g. ammonium compounds, phosphates), minerals (magnesium, iodine, iron, etc.), pesticides (e.g. nematocides) or herbicides can be supplied in a dissolved state. For dairy and poultry farms, addition of a nutrient or medicine, such as an antibiotic, can be provided by introduction of a solution containing a mixture of the chemicals into the dosing system. Figure 6 depicts a nutrient fortification system 50 in accordance with a preferred embodiment of the present invention. Water flows from a domestic water supply 51 through a check valve 52 and then optionally through a flowmeter 54 and a pressure gauge 56. While dosing unit 10 can accurately dose the fortifying nutrient solution under a wide range of inlet pressures, nevertheless nutrient fortification system 50 preferably includes an inlet pressure regulator 58 such as a 3/4" PRV pressure regulator made by BARMAD, Israel. Pressure at the inlet to dosing unit 10 should be regulated to the range of <5 atm and preferably to a range of 2-3 atm. A check valve 59 is preferably installed at the outlet 60 of nutrient fortification system 50 from which nutrient fortified water flows to a tap.

Nutrient fortification system 50 may also include an ion exchange resin in a column (not shown) to remove chloride ions and positively charged counter ions (mostly calcium and sodium) from the water and replace them partially or entirely by hydroxyl and/or hydronium ions or another pair of ions. Complete removal of a chemical compound by the ion exchange resin is preferred in some cases (e.g. arsenic in drinking water) and in others only partial removal of a nutrient by the ion exchange resin is preferred (e.g., partial removal of fluoride or sodium from drinking water). It is preferable to place the ion exchange resin before the dosing system so that the removal of chloride is proportional to the original concentration of chloride before the mixing with the magnesium chloride additive. In this way, no exchange will take place when desalinated water devoid of chloride is supplied in the grid.

Nutrient fortification system 50 may also include a column of activated carbon, beta alumina or any specific ion exchange resins (not shown) for the removal of unwanted contaminants or undesirable compounds from the water. The installation of such columns would not have negative effect on the operation of the dosing unit described herein.

Figure 7 depicts a system wherein two different water lines are supplied to the same tap 62. Tap 62 is fed hot water 66 and cold water 68 from the domestic water supply 51. Tap 62 includes an additional water supply 64 from nutrient fortification system 50. In this manner, the same tap can be used for drinking water including a fortifying nutrient and for applications such as cleaning which do not require the fortifying nutrient. EXAMPLE

Magnesium dosing at a level of 10- 35 mg/L to an intermittently opened tap

A magnesium fortification system was constructed and tested for dosing of magnesium chloride to intermittently opened tap with different flowrates (50 - 100 liters per hour) which are characteristic for kitchen water taps or whole house water supplies. Water from a residential water supply flowed through a digital flow meter (Endress+Hauser model Promag 10), a pressure gauge (ABB model 2600T), and a flow and pressure regulator (3/4" PRV pressure regulator made by BARMAD), and then to a fast hose connector (Lergis series LF3000) of a PVC main tube (part number or size). Inside the main tube was a flexible inner container made of silicone containing a solution of magnesium chloride. The fortification system was operated under different magnesium solution flowrates resulting in different concentrations of magnesium at the outlet.

The tap water flowrate during the series of experiments was set in between 98-102 L/h at a pressure of approximately 2-2.5 bar. The magnesium solution flowrate was adjusted between experiments using an adjusting screw according to the required magnesium dosing level, tap water flowrate and initial magnesium chloride concentration in the flexible inner container as described in Table 1 below. Magnesium concentration in the fortified water was measured using a HACH DR 1900 spectrometer with Magnesium kit LCK 326. The flowrate of the magnesium chloride solution was calculated based on the flowrate of the tap water and the concentrations of magnesium in the tap water, in the magnesium chloride solution and in the fortified water. The results are shown in Table 1.

Table 1 Of note is that the even at the same tap, the background level of magnesium is subject to variation. This is probably due to the different sources of water used to supply the water. This variation must be considered when setting the level of fortification so that the consumption of the fortified water does not lead to surpassing the recommended consumption of the fortifying nutrient. The recommended daily allowance of magnesium is 300-400 mg/day for adults. In view of the background levels of magnesium in the water supply, 10-35 mg/L of magnesium fortification is appropriate. Under different background conditions, a different level of fortification may be used. The level of fortification may be changed by adjusting the concentration of the magnesium in the flexible inner container of adjusting the flow rate of the fortifying nutrient solution using a flow adjusting element as described above.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.