TECHNICAL FIELD

The invention is an apparatus for providing a continuous or semi-continuos flow of a non- saturated solution comprising a predetermined concentration of one or more solutes in a solvent, using a simple mechanical arrangement, and an associated method.

BACKGROUND

Brine solutions and solutions of other solids such as sugars, drugs, cleaning fluids etc, are used in food production, healthcare, water treatment etc. It is often desirable to provide solutions in a continuous or semi-continuous manner, where the continuous production is often interrupted and restarted. It is also desirable to provide a non-saturated solution - that is, a concentration of solute in said solvent being below its saturation concentration for that solvent. Prior art methods of adjusting the concentration of a solute in a solution consist of saturating the solution and then diluting the solution to the desired non-saturated

concentration, using electronic monitoring of the solution concentration, and, typically, an electro-mechanical mixing (for example, using an electrical mixing device, an ultrasonic mixer, heating mixing chamber, etc.) to obtain a desired dilution level. Such electro mechanical methods require an electrical power supply, for either monitoring of the concentration, mixing, or both.

The relevant prior art is described in GB1376347 A (JOHNSEN O) 1974- 12-04. This document (hereinafter, Dl) describes a dosage apparatus for salting of sea-water comprising a supply conduit for fresh seawater into a sea-water tank. A portion of the sea-water from the sea water tank is branched off through a conduit via a non-return valve to a salt container which is filled with salt and into which salt is supplied from above from a hopper. In the salt container the branched off stream of sea-water is saturated with salt and flows through a conduit at the bottom of the container via a back pressure valve to the common conduit wherein it is combined with the main portion of the seawater from the sea-water tank through a conduit into the common conduit into a basin. The basin is provided with tapping devices for tapping old sea-water as the mixture of fresh sea-water and salted sea-water enters the basin, see page 3, line 125 to page 4, line 19 and drawing 1. The subject matter of claim 1 differs from Dl in specifying that the solvent inlet to the solvent reservoir is regulated by a valve or a floating level switch and by having at least a first fluid inlet to the mixing device and at least a second fluid inlet to the mixing device. Another prior art document, hereinafter D2, is US2008/0152556. D2 describes an adjustable chemical dispenser system for household or industrial use. US patent 5819776 (D3) describes a liquid de-icer production apparatus and method.

An object of the present invention is thus to provide a simple mechanical apparatus and method for producing a flow of a non-saturated solution without a need for electrically powered elements or electronic controls. Such an apparatus and the related method do not require electrical power and maintenance related to having electrical or electronical components, and, once established, it provides a continuous or semi-continuous flow of non- saturated solution, even after a shutdown and a subsequent restart. The apparatus and the method are demand-driven, supplying the required flow of non-saturated solution for other equipment located downstream. The driving force of the solute dissolvation is diffusion and flowing, whereas flowing and mixing is driven by hydraulic pressure of solvent at the inlet in the upper part of the system, and an underpressure provided by the equipment downstream to our apparatus, said equipment consuming the solvent flow generated by our invention for subsequent treatment.

Further advantages of the present technology are apparent from the following description, claims and figures

SUMMARY

In a first aspect, an apparatus is disclosed for producing a continuous or semi-continuous flow of a predetermined concentration of one or more solutes, by dissolving at least one solute in solid form, making a saturated solution, and subsequently diluting it with solvent, said apparatus comprising : one or more solids reservoirs arranged to contain a first solute in solid form, said one or more solids reservoir each having a base and at least one wall extending in an upwards direction from said base; said one or more solids reservoirs having a lower portion and an upper portion, in which the upper portion is arranged above the lower portion in said upwards direction, and an outlet located in said lower portion, or in said base; a solvent reservoir comprising a solvent inlet, regulated by a valve such as a ballcock valve, or a floating level switch; a base and at least one wall; and an outlet; a first fluid connection between the solvent reservoir and the solids reservoir, comprising a one-way flow valve or one-way membrane, allowing solvent to flow from said solvent reservoir to said one or more solids reservoir, via a first inlet for solvent arranged in the upper portion of said one or more solids reservoir, wherein the first fluid connection prevents back-flow of fluid from said one or more solids reservoir to said solvent reservoir, a mixing device, said mixing device comprising at least a first fluid inlet and at least a second fluid inlet, and at least one fluid outlet, said mixing device being arranged such that fluids flowing into first and second fluid inlets of the mixing device are mixed in a pre-determined ratio, and thereafter flow out of the at least one fluid outlet of said mixing device; a second fluid connection which allows saturated solution to flow from a first outlet arranged in the lower portion of said one or more solids reservoir to the first fluid inlet of said mixing device; a third fluid connection, which allows fresh solvent to flow from outlet of solvent reservoir to the second fluid inlet of said mixing device.

In a second aspect, a method for using the apparatus above for providing a continuous or semi-continuous flow of a non-saturated solution is described, wherein said non-saturated solution contains a pre-determined concentration of a first solute in a solvent, said method comprising the steps of: a . providing the apparatus as described herein; b. providing a first solute in solids form in the at least one solids reservoir; c. flowing fresh solvent into said at least one solids reservoir via a first inlet arranged in an upper portion of said at least one solids reservoir; and forming a saturated solution of said solute in said solvent, while the one-way first fluid connection prevents the solute from re-entering the solvent reservoir; d . flowing said saturated solution from said at least one solids reservoir via an outlet arranged in a lower portion of said at least one solids reservoir; e. mixing the flow of said saturated solution from said outlet with a flow of fresh solvent in a predetermined ratio in a mixing device, to provide a flow of a non-saturated solution containing a constant pre-determined concentration of said first solute in said solvent.

LEGENDS TO THE FIGURE

Fig . 1 illustrates a schematic of a general embodiment of the apparatus.

DETAILED DISCLOSURE

The simple mechanical multichamber hopper of this invention utilizes hydraulic pressure at inlet to solvent reservoir and/or hydraulic underpressure in the outlet line of the mixer device, without a need for a power supply, as there no electrical or electronical parts, and hence, no corrosion issues. The advantages are low cost for the apparatus itself, its maintenance and a reduction in the production cost of the solution. The salt hopper of our invention is a robust and simple alternative to current technologies.

The hopper comprises a fresh solvent reservoir and at least one solids reservoir. A one-way barrier is used to separate the solids reservoir from the fresh solvent reservoir. The one-way barrier could be chosen from a valve, particularly, a check valve, or a one-way membrane, allowing solvent to flow from solvent reservoir into said at least one solids reservoir, but preventing the solute from returning from said at least one solids reservoir into solvent reservoir.

Fresh solvent and saturated solvent are then pulled into a simple mixing device, where the hydraulic resistances of each of the lines going into the mixing device control the mixing ratio, and can be repeated using multiple saturation reservoirs (solids reservoirs) to form complex brine solutions with different compounds, using different saturated brines or switching between different saturated brines.

In a first aspect, an apparatus is provided, comprising : one or more solids reservoirs arranged to contain a first solute in solid form, said one or more solids reservoir each having a base and at least one wall extending in an upwards direction from said base; said one or more solids reservoirs having a lower portion and an upper portion, in which the upper portion is arranged above the lower portion in said upwards direction, and an outlet located in said lower portion, or in said base; a solvent reservoir comprising a solvent inlet, regulated by a valve such as a ballcock valve, or a floating level switch; a base and at least one wall; and an outlet; a first fluid connection between the solvent reservoir and the solids reservoir, comprising a one-way flow valve or one-way membrane, allowing solvent to flow from said solvent reservoir to said one or more solids reservoir, via a first inlet for solvent arranged in the upper portion of said one or more solids reservoir, wherein the first fluid connection prevents back-flow of fluid from said one or more solids reservoir to said solvent reservoir, a mixing device, said mixing device comprising at least a first fluid inlet and at least a second fluid inlet, and at least one fluid outlet, said mixing device being arranged such that fluids flowing into first and second fluid inlets of the mixing device are mixed in a pre-determined ratio, and thereafter flow out of the at least one fluid outlet of said mixing device; a second fluid connection which allows saturated solution to flow from a first outlet arranged in the lower portion of said one or more solids reservoir to the first fluid inlet of said mixing device; a third fluid connection, which allows fresh solvent to flow from outlet of solvent reservoir to the second fluid inlet of said mixing device.

The valves (55) on the inlet lines to the mixing device offer an advantage of disconnecting and reconnecting the apparatus (or shutdown and restarted), and the same predetermined concentration of said first solute in said solvent can be achieved without recalibration.

Suitably, each first fluid connection between the solvent reservoir and each of the solids reservoir, if multiple, comprises a one-way flow valve (55) or one-way membrane (55), which prevents backflow of fluid from said solids reservoir to said solvent reservoir. This helps to prevent solute from contaminating the supply of fresh solvent.

Details of the solvents and solutes relevant for the apparatus described herein, are set out below under the method of the invention. Suitably, the first outlet for saturated solution from said solids reservoir is arranged in the base of said solids reservoir. A barrier (e.g. a filter) is typically located between the first inlet for solvent in the upper portion of said solids reservoir; and the first outlet arranged in the lower portion of the solids reservoir, to support solid solute and prevent it from flowing out through said first outlet together with the saturated solution.

The apparatus is typically passive, i.e. not requiring power, and not comprising pumps, etc. Further components of the apparatus (e.g. valves, fluid pipes etc.) can be incorporated into this apparatus by the skilled person, as required.

In a second aspect, a method is provided for continuous or semi-continuous production of a flow of a non-saturated solution. The non-saturated solution contains a predetermined concentration of a first solute in a solvent. The predetermined concentration of solute in the non-saturated solution is suitably less than 99 vol% (quasi saturated solution), such as less than 95 vol%, less than 90 vol%, less than 80 vol%, less than 75 vol%, less than 60 vol%, less than 50 vol%, less than 25 vol%, less than 10 vol% or less than 5 vol%.

The pre-determined concentration of solute in the non-saturated solution is suitably greater than 0 vol.% (pure solvent), such as greater than 1 vol%, greater than 5 vol%, greater than 10 vol%, greater than 15 vol%, greater than 20 vol%, greater than 25 vol%, greater than 50 vol%, greater than 60 vol% or greater than 90 vol%.

Suitably, the concentration of one or more solutes in the non-saturated solution is between 1 ppm and the respective saturation concentration of said one or more solutes for said solvent at a given temperature.

Generally, the method comprises the steps of: a. providing the apparatus as described herein;

b. providing a first solute in solids form in the at least one solids reservoir;

c. flowing fresh solvent into said at least one solids reservoir via a first inlet arranged in an upper portion of said at least one solids reservoir; and forming a saturated solution of said solute in said solvent, while the one-way first fluid connection prevents the solute from re-entering the solvent reservoir;

d. flowing said saturated solution from said at least one solids reservoir via an outlet arranged in a lower portion of said at least one solids reservoir;

e. mixing the flow of said saturated solution from said outlet with a flow of fresh solvent in a predetermined ratio in a mixing device, to provide a flow of a non-saturated solution containing a constant pre-determined concentration of said first solute in said solvent.

The first solute is typically selected from salts (such as, for example, a halide salt of a Group I or Group II metal), or sugars, or a mixture thereof. Preferably, the first solute is a salt, most preferably, the salt is NaCI. Other possible first solutes include foodstuffs (e.g. sugars, proteins or other soluble foodstuffs), cleaning or disinfecting materials (e.g. surfactants or antimicrobials) or medicaments (drugs). The first solute is typically present in the solids reservoir in the form of granules.

Typically, the solvent is water or an alcohol, or a mixture thereof; most preferably, the solvent is water. The solvent may comprise other solutes than the first one, such as mineral salts, before being introduced into the solids reservoir, particularly, if tap-water is used as a solvent. The term "fresh solvent" is taken to mean the particular solvent in question, substantially without the solute in question. In one aspect, the solvent is sterile. In another aspect, the solvent is essentially pure.

At least one solids reservoir is provided, which contains a first solute in solid form. The solids reservoir has a base and at least one wall, such as e.g. three or four walls. The wall(s) extend in an upwards direction from said base. Typically, the solids reservoir is cylindrical, with a substantially circular base. The solids reservoir may be made of any suitable materials, preferably plastic.

The solids reservoir has a lower portion and an upper portion, in which the upper portion is arranged above the lower portion in said upwards direction. Typically, the solids reservoir has an opening at the upper portion thereof - optionally with a lid - through which the first solute can be added, monitored and topped up as required.

Fresh solvent is flowed into theone or more solids reservoirs via a first inlet arranged in the upper portion of said one or more reservoirs. The flow of fresh solvent into said at least one solids reservoir is regulated by a one-way flow valve or one-way membrane, which prevents back-flow of fluid from said solids reservoir. This helps to prevent solute from contaminating the supply of fresh solvent.

The first inlet may be provided in the wall of the reservoir, or in a top surface thereof, opposite the base. The use of valves such as ballcock valves allows the non-saturated solution to be provided "on demand", by applying negative pressure to the outlet of the mixing device. Fresh solvent may be obtained directly from source, e.g. a water tap. Advantageously, a solvent reservoir is further provided, said solvent reservoir having a base and at least one wall, said solvent reservoir being arranged in fluid connection with the first inlet of said solids reservoir such that fresh solvent flows from said solvent reservoir to said solids reservoir. The solvent reservoir further comprises an inlet for the solvent into the reservoir, said inlet is fitted with a valve. Suitably, flow of fresh solvent into said solvent reservoir is regulated by said valve, such as, for example, a ballcock valve.

Solvent thus mixes with the solute contained in the at least one solids reservoir, and a saturated solution of said solute in said solvent is thus formed.

The saturated solution is flowed from the solids reservoir via an outlet arranged in a lower portion of said solids reservoir. To ensure that a saturated solution is obtained via the outlet, the outlet is preferably arranged in the base of the solids reservoir. A barrier (e.g. a filter) is typically located between the first inlet for solvent in the upper portion of said solids reservoir; and the first outlet arranged in the lower portion of the solids reservoir, to and prevent undissolved solute from flowing out through said first outlet together with the saturated solution.

The flow of said saturated solution from the outlet of the solids reservoir is mixed with a flow of fresh solvent at a predetermined ratio in a mixing device. The mixing device comprises at least a first fluid inlet, at least a second fluid inlet, and at least one fluid outlet. Typically, these are combined together using a Y- or T-junction tubing, resulting in one outlet flow combining the two inlet flows. Additional tubing, valves (55) or mixing elements may be incorporated as required.

In one aspect, the flow of fresh solvent into said mixing device and/or the flow of saturated solution into said mixing device is regulated by a valve (55) such as a needle valve.

Preferably, the flow of saturated solution into said mixing device is regulated by a valve. The use of valves in this manner has the advantage that, once a predetermined concentration of said first solute in said solvent is obtained, the apparatus can be stopped, even for a significant length of time, and started again, without needing to recalibrate in order to achieve the predetermined concentration.

A flow of a non-saturated solution containing a constant predetermined concentration of said first solute in said solvent, preferably being below the saturation concentration of said first solute in said solvent, is thus provided. The flow of non-saturated solution may be provided continuously or semi-continuously (i.e. drop-wise, or as an interrupted continuous process). Suitably, a single source of fresh solvent provides the solvent into the solvent reservoir, and the solvent reservoir supplies both the flow of fresh solvent into said solids reservoir, and the flow of fresh solvent into said mixing device.

Applying negative pressure (suction or underpressure) to the fluid outlet of the mixing device moves saturated solution from at least one solids reservoir, as well as such negative pressure moves the fresh solvent from the solvent reservoir into the mixing device, and ensures the flow of solvent into the the solids reservoir through the first liquid connection (with a one way flow control). The method can therefore be carried out passively, i.e. without the use of electrical activators such as pumps.

Furthermore, the method can be used to provide a flow of a non-saturated solution containing a constant predetermined concentration of two or more solutes in said solvent.

This is accomplished by using at least two separate solids reservoirs, each arranged to contain different solutes in solid form.

Each of the solids reservoirs has the structure and arrangement set out above, i.e. having a base and at least one wall, a lower portion and an upper portion, in which the upper portion is arranged above the lower portion in the upwards direction, and inlets and outlets as set out above.

In this case, the method comprises: a . flowing fresh solvent into each solids reservoir via first inlets arranged in the upper portions of each solids reservoirs; and thereby forming saturated solutions of each solute in said solvent in each separate solids reservoirs; b. flowing said saturated solutions from each of said solids reservoirs via outlets

arranged in the lower portions of each solids reservoir; c. mixing the flows of said saturated solutions from each of said outlets with each other, and with a flow of fresh solvent in a predetermined ratio in a mixing device, to provide a flow of a non-saturated solution containing a constant pre-determined concentration of each of said solutes in said solvent, being below the saturation concentration of said solutes in said solvent.

Further solvent reservoirs and solids reservoirs, and their required inlets/outlets and connections can be incorporated as needed . Specific embodiments of the invention

The apparatus of Figure 1 will now be described. Figure 1 shows a schematic of a general embodiment of the apparatus 10.

A solids reservoir 20 is arranged to contain a first solute 100 (e.g. salt) in solid form. The solids reservoir 20 has a base 21 and at least one wall 22 extending in an upwards direction from said base 21. In this illustrated embodiment, the solids reservoir is essentially cylindrical. The solids reservoir further comprises an inlet 24 from the first fluid connection 40. This inlet is configured with a one-way flow device, such as a valve or a membrane, preventing the solute in solids reservoir 20 from entering into the solvent reservoir 30. The solids reservoir 20 has a lower portion and an upper portion (not labelled), in which the upper portion is arranged above the lower portion in said upwards direction. A barrier 28 prevents the undissolved solute 100 from exiting the solids reservoir 20 through the outlet 25 situated either in the lower part of reservoir 20, in or close to its base 21.

A solvent reservoir 30 is provided, in order to contain a solvent 110. This reservoir has a base 31 and at least one wall 32. In the illustrated embodiment, the solvent reservoir 30 and solids reservoir 20 are shown to be adjacent, and to share one wall. Although this is an effective use of space, which reduces the need for long tubing, it is not the only conceivable arrangement of these two reservoirs. One possible arrangement is where the solvent reservoir 30 is located above the solids reservoir (in the upwards direction), and gravity can be used to promote solvent/solution flow through the apparatus. A solvent inlet 33 can be provided with a ballcock-type valve, to ensure a certain level of the solvent in the reservoir. An outlet 34 is providing the solvent into the third liquid connection leading the solvent to the mixer device.

A first fluid connection (e.g. tubing) 40 allows solvent 110 to flow from said solvent reservoir 30 to said solids reservoir 20, via a first inlet 24 for solvent arranged in the upper portion of said solids reservoir 20. The solvent flows down inside the solids reservoir 20, creating a saturated solution of said solid. Depending on the relative flow rates, the solids reservoir 20 may fill with solvent 110. Barrier, e.g. a mesh, 28 is in the middle of the solids reservoir, to prevent solid solute from flowing out through said first outlet together with the saturated solution.

A second fluid connection 26 allows saturated solution to flow from a first outlet 25 arranged in the lower portion of said solids reservoir 20 to the first fluid inlet 51 of mixing device 50. A third fluid connection 27 allows fresh solvent to flow from said solvent reservoir 30 to the second fluid inlet 52 of mixing device 50.

Mixing device 50 comprises first fluid inlet 51 and second fluid inlet 52, and fluid outlet 53, and is arranged such that fluids flowing into first and second fluid inlets 51, 52 are mixed at a predetermined ratio, and thereafter flow out of the at least one fluid outlet 53 of said mixing device.

The invention has been described with reference to a number of embodiments and aspects. However, the person skilled in the art may amend such embodiments and aspects while remaining within the scope of the appended patent claims. In particular, a plurality of solvent reservoirs and solids reservoirs - and any connecting tubing or valves - may be included in the method and apparatus as required.

EXAMPLE 1

The inventive apparatus produces, continuously or semi-continuosly, a salt brine containing 1.5 grams of NaCI for each litre of water. This product, 0.15 mass% NaCI solution, is continuously or semi-continuously flowing into an ECA cell for electrolysing it into a mixture of HCIO and NaOH, thus producing an Electro-Chemically Activated (ECA) Water.

The apparatus comprises two reservoirs, where a first reservoir holds fresh water and the second holds a saturated brine solution (350 grams of NaCI per litre). The two fluids (fresh water and saturated brine) are pulled into the ECA machine through the tubes connecting the outlets of each of the two reservoirs with the two respective inlets of the mixing device, and leaving the mixing device via a single outlet into the feeding line for the subsequent introduction of the NaCI solution into the ECA machine. Restricting the flow from the solute reservoir allows the ratio between the saturated fluid and the fresh water to be controlled. The lines from each of the reservoirs have a variable screw valve, thus allowing for adjustment of the flow restriction on the two lines. In this particular case, the flow volume ratio of fresh water to the saturated fluid is approximately 233.

The fresh water reservoir is connected to a pressurized water source through a floating level switch, which ensures the fresh water level in the system. Check-valves are placed from the fresh water reservoir into the saturation reservoir, avoiding backflow of salt or saturated solution. The check-valve fills the saturation reservoir with fresh water and ensures the fluid level. The solute reservoir is filled with excess salt, such that the fluid is saturated. At the bottom of the solute reservoir is a barrier (i.e. a filter), to hold the undissolved salt back. The brine solution is pulled into an electrochemical cell that electrolyses the salt and forms a cleaning solution, containing predominately HCIO and NaOH.