SYSTEM AND METHOD FOR COLLECTING WATER FROM UNDERWATER AND / OR COASTAL SOURCES WITH OVERFLOW BASIN

Description

Technical field

[0001] The invention relates to the field of capturing water flowing into the sea (submarine, coastal sources) whose salinity is lower than that of seawater, in particular, fresh water or drinking water in order to use it for populations and / or crops and / or livestock. Previous technique

[0002] There are many techniques for collecting water from springs that flow into the sea.

[0003] We are particularly familiar with patent application FR 2,857,389 which concerns a collection system allowing part of the fresh water to be discharged into the sea when the fresh water flow is too high, in the event of a flood of the source for example.

[0004] However, this system can generate pressure variations at the source outlet into the sea, thus inducing a decrease in the source's flow rate and causing the source to exit through another channel.

[0005] Another technique involves inserting a pipe directly at the spring outlet and creating a watertight connection between the pipe and the outlet, thus forcing the spring water into the intake system. This technique is described in French patent application FR 2,792,664. This technique alters pressure balances and can therefore modify the spring's flow rate by creating a preferential pathway for the water through an outlet other than the one where the intake system was implemented. Furthermore, this blockage of the spring water can disrupt the local marine ecosystem, as the fauna and flora at the spring outlet are accustomed to a lower salinity than that of seawater.

[0006] Another technique involves using a bell jar above the spring's outlet. Patent applications WO2009 / 001,145, FR2,926,569, FR2,795,109, and WO2007 / 017,703 relate to such a technique. Because spring water has a lower density than seawater, it rises and is trapped inside the bell jar. A pipe and pump then carry the water to the surface or to land. However, the larger the bell jar, the more thoroughly the spring water and seawater will mix, resulting in the collected water being saltier than the water flowing from the spring. Furthermore, the use of the pump creates a vacuum, disrupting the pressure balance and potentially causing some of the salt water to enter the system. Consequently, the recovered water will be saltier than the water initially flowing from the spring.Furthermore, since the pump generates a vacuum, real-time monitoring of the pump may be necessary to adapt it to pressure variations. The use of real-time monitoring adds complexity to the system. Summary of the invention

[0007] To overcome the drawbacks of the prior art, the invention seeks to capture water from a submarine spring without altering the pressure balance (or with a slight overpressure) at the spring's outlet, preventing the spring from finding another outlet and thus preventing the capture of salty seawater. By minimally altering the pressure balance, we mean that the pressure at the spring's outlet remains unchanged or is slightly overpressured, the value of which depends on the spring's conditions (presence or absence of other nearby spring outlets, pressures, temperature, salinity, etc.), and that the spring's flow rate will be minimally affected by any slight overpressure; for example, the flow rate of the spring with or without the capture system of the invention varies by less than 5%.Thus, the invention does not generate a depression at the outlet of the source, unlike prior art systems which use a pump to recover fresh water at the outlet of the source.

[0008] To this end, the invention relates to a water collection system from at least one water source opening through a subsea outlet comprising at least one separation means for separating the water from the source from the seawater (one separation means for each water source), each separation means being connected to an overflow basin comprising an opening for the entry of the water from the source, and one (at least one) water recovery device (a single water recovery device or several, for example a separate water recovery device linked to each source), each overflow basin comprising an overflow wall configured so that the water from the source passes over said overflow wall to enter the water recovery device by gravity.Furthermore, the overflow section at the outlet of each overflow basin is strictly greater than the passage section of the opening of the overflow basin considered and the overflow section (horizontal) of the overflow basin is located above sea level.

[0009] The invention relates to a water intake system from at least one underwater water source comprising at least one separation means for separating the water from at least one source from the seawater, each separation means being connected to a separate overflow basin, each overflow basin comprising an opening for the entry of water from at least one source, the intake system comprising at least one water recovery device, each overflow basin comprising an overflow wall configured so that the water from at least one source passes over said overflow wall to enter, by gravity, into at least one recovery device.Furthermore, within each overflow basin, the overflow section of said overflow basin is strictly greater than the section of said opening of said overflow basin, and in that the overflow section of the overflow basin is situated strictly above sea level.

[0010] Preferably, each separation means is connected to the opening of the overflow basin by a pipe, the water passage cross-section in each pipe being strictly less than the maximum water passage cross-section in the separation means to which the pipe is connected and in the maximum water passage cross-section in the overflow basin to which the pipe is connected.

[0011] Advantageously, at least one means of separation includes an envelope, preferably a flexible envelope.

[0012] Preferably, the at least one separation means includes at least one non-return valve capable of allowing water from said source to pass outside the separation means and preventing seawater from passing into the separation means. Advantageously, said overflow wall of at least one overflow basin has the shape of a concave bowl, the opening of this at least one overflow basin being positioned at the bottom of the concave bowl, and preferably, the recovery device surrounding the concave bowl.

[0013] According to one variant of the invention, at least one overflow basin is formed by a caisson comprising the overflow wall, the overflow wall separating the overflow basin on one side from the overflow wall of the recovery device on the other side of the overflow wall.

[0014] According to one configuration of the invention, the system includes an adjustment means for adjusting the overflow section altitude of at least one overflow basin at least at the time of installation of the collection system, preferably, the system includes an adjustment means for adjusting the overflow section altitude of at least one overflow basin according to variations in flow rates and / or pressure and / or variation in density of seawater or water from at least one source.

[0015] Preferably, the vertical distance zc between the outlet of each underwater source and the level of the overflow section of each overflow basin to which said outlet is connected is determined by the following formula: z c = ρ m ⋅ z s ⋅ g + Δ p ρ s ⋅ g

[0016] With zs the depth of the outlet of the considered underwater source relative to sea level, g the acceleration due to gravity, Δ pa predetermined overpressure value greater than or equal to zero, defined according to the characteristics of the source considered, p m the density of seawater and p s the density of the water from said underwater source considered.

[0017] According to one embodiment of the invention, at least one recovery device includes a pump configured to start when the water level in the recovery device exceeds a first predetermined threshold and configured to stop when the water level is below a second predetermined threshold, the second predetermined threshold being less than or equal to the first predetermined threshold.

[0018] Advantageously, the collection system includes a water storage means and a supply conduit connecting at least one water recovery device to the storage means, the storage means being floating, and preferably able to be disconnected from the supply conduit, or placed on the ground.

[0019] Preferably, at least one water recovery device is floating and anchored to the ground by cables, preferably by tensioned cables, or laid on the ground onshore or offshore.

[0020] Advantageously, at least one water recovery device includes an orifice to permit the introduction of water from an outlet of an additional water source, the orifice permitting the water from said additional water source to enter at least one water recovery device directly or indirectly, the at least one recovery device preferably including a control means to control the water level in at least one water recovery device when the orifice is below the water level.

[0021] According to an advantageous configuration of the invention, the collection system is configured to collect water from several underwater sources, said collection system comprising as many means of separation and overflow basins as there are sources, each means of separation being connected to a separate overflow basin, preferably the collection system comprising a single water recovery device to recover water from all the overflow basins.

[0022] The invention also relates to a method for capturing water from at least one underwater water source, in which at least the following steps are carried out using the capture system as described above: The water from at least one source is separated from the seawater at the level of a subsea outlet, by at least one means of separation; The water separated from the seawater is conveyed to the opening in the overflow basin; The speed of the water in the overflow basin is slowed down by means of an overflow section of the overflow basin strictly greater than the water passage section in the opening; The water is overflowed from the overflow basin and the water is recovered, by gravity, in the recovery device, the recovery device being floating or placed on the ground, onshore or offshore, and preferably, the water is transferred from the water recovery device to a floating storage means and the floating water storage means is towed by a boat to land. List of figures

[0023] Other features and advantages of the system and method according to the invention will become apparent from the following description of non-limiting examples of implementations, with reference to the figures attached and described below. There figure 1 represents a first embodiment of a water collection system according to the invention. figure 2 represents different operating modes a), b), c) and d) of a water collection system according to the invention. figure 3 represents a second embodiment of a water collection system according to the invention. figure 4 represents a third embodiment of a water collection system according to the invention. figure 5 represents a fourth embodiment of a water collection system according to the invention. figure 6 represents a fifth embodiment of a water collection system according to the invention. figure 7represents the principle of a lifting pump within the water recovery device of a collection system according to the invention. figure 8 represents a means of guidance at the outlet of the overflow basin of a catchment system according to the invention. figure 9 represents a sixth embodiment of a water collection system according to the invention. figure 10 represents a seventh embodiment of a water collection system according to the invention. figure 11 represents a top view of the water intake system of the figure 1 according to the invention. The figure 12 represents a top view of a water catchment system where the overflow basin is formed by a caisson with an overflow wall separating the overflow basin from the recovery device located on the other side of the overflow wall. Description of the modes of realization

[0024] The terms "high", "low", "level", "altitude", "lower", "higher" refer to the system or method of the invention in its operating and operational position.

[0025] The terms "inlet" and "outlet" are understood in the sense of the flow of the fluid (water) in the system or part of the system under consideration.

[0026] By "overflow level" we mean the level from which a water / air interface occurs.

[0027] By "overflowing," we mean that water passes over a wall and falls into another container. The overflowing action occurs at the point where it is located.

[0028] By "overflow section" we mean the section through which the water passes at the overflow level, this section being in the horizontal plane of the overflow level.

[0029] The invention relates to a system for capturing water from at least one water source with an underwater outlet. The source is a freshwater or slightly saline water source. "Slightly saline" means that the salinity of the water in the source is lower than that of seawater, and more specifically, lower than that of the seawater at the point where the source is located. Capturing this freshwater or slightly saline water is particularly advantageous for providing freshwater (or drinking water) to people and / or livestock and / or for use in agriculture.

[0030] By capturing water from several underwater sources, certain elements can be pooled, which helps to reduce costs and lessen the environmental impact on fauna and flora.

[0031] To achieve this, the water intake system includes at least one separation device, at least one overflow basin (also called an overflow means), and at least one water recovery device (also called a recovery means). Each separation device separates the water exiting a subsea spring from the surrounding seawater. This prevents, or at least minimizes, mixing between seawater and spring water, thus preventing the salinity of the captured (or produced) spring water from increasing relative to that of the water exiting the spring.

[0032] Each separation unit is connected (directly or indirectly via a pipeline) to a separate overflow basin. Thus, the water from each underwater source that has been separated from the seawater in the separation unit is conveyed to the overflow basin. To facilitate this, each overflow basin includes an opening for the inflow of water from the separation unit, either directly or indirectly via a pipeline.

[0033] By using the same fixed number of separation means and overflow basins, it is possible to capture the water corresponding to the same fixed number of different sources.

[0034] The recovery device can receive water from all sources: in this case, the collection system includes a single water recovery device, which simplifies the system.

[0035] Alternatively, each overflow basin can be associated with a separate recovery unit that can receive water from a single source. In this case, the catchment system includes as many recovery units as there are sources, and therefore as many recovery units as there are separation devices (and overflow basins). For each source, the system will have a separate separation device, a separate overflow basin, and a separate recovery unit. This allows, for example, the management of different outlet water salinities or different water compositions.

[0036] According to another alternative, the catchment system could include several water recovery devices, the number of which would be fewer than the sources (and therefore fewer than the number of separation devices). In this variant, at least one water recovery device would be shared by several overflow basins. This can be advantageous for waters with similar chemical compositions or salinities, for the purpose of similar future treatment.

[0037] According to the invention, each overflow basin comprises an overflow wall configured so that the water from the source (or at least one of the sources) associated with the overflow basin passes over the overflow wall to be conveyed (to enter directly) into the water recovery device (or one of the water recovery devices) by gravity: in other words, the water overflows over the overflow wall and then falls by gravity into the water recovery device (or one of the water recovery devices). The recovery device may, for example, surround the overflow basin so that the water exiting the overflow basin falls directly by gravity into the recovery device.

[0038] Alternatively, the overflow wall can separate the overflow basin from the recovery device.

[0039] In a marine environment, because the salinity of the spring water is lower than that of seawater, its density is also lower, and consequently, the spring water naturally rises above the sea surface. When a water column is installed, this effect is eliminated. However, thanks to the hydrostatic pressure generated by the aquifer associated with the spring, the water still naturally rises within the column. Its operation is then similar to that of an artesian well on land. Therefore, the system does not require a pump to transport the water from the spring outlet to the overflow basin, and thus, the system does not generate negative pressure and avoids drawing seawater into the produced water.

[0040] Preferably, the system can be designed so that the pressure of the water column exiting the underwater source is in hydrostatic equilibrium with the pressure of the seawater column located above the outlet of the underwater source so as not to disturb the pressure balance.

[0041] To maintain hydrostatic equilibrium at the outlet of the underwater spring, the pressure of the water column exiting the spring above the outlet is preferably equal to (or very slightly greater than, for example, between a few millibars and 100 mbar (0.01 MPa)) the pressure exerted by the seawater. This can be adjusted by the height of the water column from the underwater spring.

[0042] Thus, we have: Ps = Pa + ρ m ⋅ g ⋅ z s = Pa + ρ s ⋅ g ⋅ z c

[0043] Where Ps is the hydrostatic pressure at the outlet of the considered underwater source At atmospheric pressure p m the density of seawater zs the depth of the considered underwater outlet relative to sea level (which therefore corresponds to the height of the seawater column above the outlet of the considered underwater source) p s the density of the water from the considered underwater source corresponding to the density of the water produced (i.e., the water captured by the capture system) zc The height of the water column from the underwater spring required to maintain the hydrostatic pressure at the outlet of the spring remains unchanged. g is the acceleration due to gravity.

[0044] Alternatively, the system can be designed so that the pressure of the water column exiting the underwater spring is very slightly higher, by a predetermined value, than the pressure of the seawater column located above the outlet of the underwater spring. This prevents seawater from entering the system (especially if the intake system is not completely watertight) and minimizes disturbances to the hydrostatic equilibrium, thus avoiding any loss of flow from the spring. Indeed, if the hydrostatic equilibrium is sufficiently disturbed, the water source's flow rate may be significantly reduced, or even completely eliminated, as the spring could find a more favorable outlet in the Earth's subsoil. The predetermined value of the overpressure depends on the spring and its conditions. This predetermined value could, for example, be a few millibars, for instance, less than 100 mbar (0.01 MPa) so as not to disturb the flow from the source too much. Thus, the pressure at the source, after installation of the capture system, is then: . Ps + Δp = Pa + ρ m ⋅ g ⋅ z s + Δp = Pa + ρ s ⋅ g ⋅ z c

[0045] Where Ps is the "normal" hydrostatic pressure at the outlet of the considered underwater source. By "normal," we mean natural, that is, the pressure without the intake system. At atmospheric pressure p m the density of seawater zs the depth of the considered underwater outlet relative to sea level (which therefore corresponds to the height of the seawater column above the outlet of the considered underwater source) p s the density of the water from the considered underwater source corresponding to the density of the water produced (i.e., the water captured by the capture system) zcthe height of the water column of the underwater spring required so that the hydrostatic pressure at the outlet of the spring in question is here in very slight overpressure of the value Δp . Δp : predetermined overpressure value ( Δp is positive) g the acceleration due to gravity

[0046] In this alternative, a slight predetermined value of overpressure is tolerated. Δp , the height of the water column from the source in the catchment system is then greater than the height of the water column from the source in the catchment system where the pressure balance is strictly respected.

[0047] Thus, we obtain a column of water whose height can satisfy the following equation: z c = ρ m ⋅ z s ⋅ g + Δ p ρ s ⋅ g

[0048] With Δp ≥ 0: if Δp = 0, then the hydrostatic pressure equilibrium is respected, if Δp> 0, the collection system allows a slight overpressure of predetermined value corresponding to Δp This predetermined value is configured to prevent seawater from entering the intake system, especially if the system is not completely sealed, and to have little or no impact on the flow rate of the source (for example, the variation in flow rate with or without the intake system may be less than 5%).

[0049] However, like the density of seawater p m is greater than the density of the water in the underwater spring p s Since spring water has a lower salinity than seawater, the freshwater column is higher than the seawater column. In other words, the freshwater column emerges above the seawater surface. Consequently, the elevation of the overflow section (which is the highest point of the water column emerging from the spring) is above sea level.

[0050] Thus, by maintaining hydrostatic equilibrium or generating a slight overpressure in the freshwater column, the system operates autonomously without human intervention. It is therefore simple to use and does not require real-time monitoring, unlike catchment systems that use a pump to transport water from the source to a storage basin.

[0051] The overflow section (corresponding to the outlet section) of the overflow basin is defined by the outlet of the overflow basin. It therefore corresponds to the horizontal section of the overflow basin at the upper level of the overflow wall.

[0052] Furthermore, to limit the height of the water jet above the overflow basin, which could be influenced by the pressure of the underwater spring, it is necessary to slow the water flow at each overflow basin. To achieve this, the overflow area (outlet) of each overflow basin is strictly larger than the opening area (where the water enters the overflow basin). This results in a wider cross-section, thus slowing the flow and consequently reducing the jet height.

[0053] Advantageously, the intake system may include at least one pipe to connect a separation device to a separate overflow basin, thereby conveying the water from the source to that overflow basin. The cross-sectional area of ​​the water in the pipe is smaller (preferably strictly smaller) than the maximum cross-sectional area of ​​the water in the separation device to which the pipe is connected and the maximum cross-sectional area of ​​the water in the overflow basin to which the pipe is connected. Thus, the pipe can be smaller than both the separation device and the overflow basin, thereby limiting the environmental impact (particularly on fauna and flora) of the intake system.

[0054] Preferably, each separation point can be connected to the opening of a separate overflow basin via a pipe. This allows water to be collected from multiple sources and conveyed to a single location for overflow and water recovery, further minimizing environmental impact and providing greater design and manufacturing flexibility for the system.

[0055] Maximum cross-section refers to the largest cross-sectional area in the direction of water flow.

[0056] Preferably, at least one of the separation means (in particular each separation means) may include a casing to establish a physical separation between the seawater located on one side of the casing (for example, outside the casing) and the spring water located on the other side of the casing (for example, inside the casing). This physical separation prevents mixing between these two miscible waters.

[0057] For example, the enclosure can be flexible, such as a plastic sheet. By flexible, we mean that it can deform to be easily positioned on site during installation, unlike a rigid enclosure which cannot be deformed without special tools during installation.

[0058] According to one feature of the invention, the envelope (flexible or rigid) can be fluid-tight (seawater and freshwater) to prevent any possible mixing between these fluids.

[0059] According to one embodiment of the invention, at least one of the separation means (in particular each separation means) may include a ballast means placed on the ground. This ballast means may consist of a weight placed on the ground. This ballast means allows the separation means of the intake system to be maintained in the intended position, surrounding the outlet of the considered seawater source, and preferably ensures a seal between the separation system and the ground. To ensure a seal, the ballast means must be deformable to follow the imperfections of the ground. To this end, the ballast means may include a torus made of a flexible fabric (deformable without the use of special tools) and filled with solid particle material (concrete beads, sand, for example).The solid particles provide weight enabling the system to function as a ground ballast, and the combination of the flexible fabric and solid particles allows the ballast to deform to adapt to variations in the ground.

[0060] Preferably, the ballast means can be attached to the (flexible or rigid) casing, preferably watertight, to ensure separation with the least possible mixing between seawater and the water from the underwater source considered.

[0061] Advantageously, at least one of the separation means (preferably the housing of the separation means, and even more preferably, each housing of each separation means) may include at least one check valve capable of allowing the source water to pass through the check valve of the separation means in question to reach the seawater and of preventing the seawater from passing through this check valve to reach the produced source water. By preventing the passage of seawater through the separation means (via the check valve), the increase in salinity of the water produced by the intake system is avoided or limited. Thus, the water requires little or no desalination before being used for human, livestock, or agricultural purposes.Furthermore, by allowing the passage of fresh water into the seawater, the flow rate can be limited, thus preventing excessive local overpressure that could be induced on the separation device, particularly in the case of a flexible casing, and potentially on the pipeline itself, and avoiding a significant water jet at the overflow basin. This local overpressure can be generated, for example, when the spring is in flood and the outflow exceeds the flow rate that can be produced by the intake device (for example, due to pressure losses in the pipeline).

[0062] The check valve can be configured to open based on a predetermined criterion. This predetermined criterion can preferably correspond to the predetermined overpressure value of the water column at the source, the predetermined overpressure value being dependent on the source conditions. Therefore, a slight overpressure in the water column can be allowed to prevent seawater from entering the intake system. Limiting the flow rate using the check valve can also be advantageous when the volume of the recovery unit is limited (e.g., tank volume), for example, to prevent the water level in the recovery unit from exceeding the overflow section.

[0063] Advantageously, at least one check valve (preferably for each separation method) can be configured so that its opening pressure is set at a level higher than the seawater pressure at the check valve, thus preventing leakage. This configuration allows for automatic opening of the check valve based on pressure, without human intervention or electrical or hydraulic control, thereby simplifying the system.

[0064] According to one implementation, at least one separation means (or each separation means) may include several check valves regularly distributed over the separation means considered (in particular on the casing) around the outlet of the underwater source considered, so as to reduce or eliminate overpressure on the separation means.

[0065] Advantageously, the check valve(s) can be positioned on the rigid or flexible casing of at least one separation means (preferably of each separation means).

[0066] Preferably, the cross-sectional area at the outlet of each overflow basin S b can be determined by the following Bernoulli formula as a function of the envisaged jet height: S b = Q c 2 gH j

[0067] With Qc the flow rate of water produced in the overflow basin considered, g the acceleration due to gravity and Hj the envisaged height of the jet.

[0068] For example, the cross-sectional area at the outlet of each overflow basin Sb can be at least 1.5 times, preferably at least 2 times, the cross-sectional area of ​​the pipe or opening of the overflow basin in question. As a result, the velocity is reduced when the water enters the overflow basin.

[0069] The diameter of the pipe D c can be determined so that the pressure losses Δh in the pipe of length L c are less than a predetermined criterion Δ h crit depending on the project in which a water intake system is to be implemented (particularly depending on the depth of the source, the source pressure at its outlet, its flow rate, etc.). For example, D c can be determined such that: Δ h = λ L c D c v c 2 2 g ≤ Δ h crit

[0070] With vc the velocity of the water in the pipe, λ a coefficient depending on the roughness of the internal surface of the pipe and g the acceleration due to gravity.

[0071] According to one embodiment of the invention, the overflow wall of at least one overflow basin can form a concave bowl, the opening of this overflow basin being positioned at the bottom of the bowl or on one side of the bowl at a level lower than the upper section of the bowl, which constitutes the overflow section. When this overflow basin is connected by a pipe to the separating means to which it is connected, the connection with the pipe corresponds to the position of the opening, either at the bottom of the concave bowl (at the lowest point of the concave bowl) or on one side of the bowl at a level lower than the upper section of the bowl. This results in a gradual widening of the passage cross-section from the pipe to the outlet of the overflow basin. This helps to limit fluid disturbances, particularly turbulence.

[0072] In this embodiment, the water recovery device (either a single device for all overflow basins in the system or one associated exclusively with the overflow basin in question) can advantageously surround the wall of the concave bowl. Thus, the water overflowing all around the concave bowl can be collected in the water recovery device, minimizing the loss of water produced.

[0073] Additionally or alternatively, at least one overflow basin may be formed by a caisson, preferably parallelepiped-shaped, comprising the overflow wall. In other words, one of the vertical walls of the caisson may form the overflow wall. The overflow wall has a top level lower than the top level of the other lateral walls of the caisson.

[0074] For example, one can have a collection system with an overflow basin which has an overflow wall in the form of a concave bowl and another overflow basin which is in the form of a box, one of whose walls forms the overflow wall.

[0075] The box can, for example, be a parallelepiped box made up of four flat vertical walls, one of which serves as an overflow wall.

[0076] When the overflow basin is formed by a caisson, the caisson's overflow wall separates the overflow basin (on one side of the overflow wall) from the recovery device (on the other side of the overflow wall), which can advantageously be parallelepiped to facilitate the system's manufacture.

[0077] The overflow wall ensures a watertight seal between the overflow basin's caisson and the water recovery system. In other words, spring water can flow from the overflow basin to the water recovery system only when the water level in the overflow basin exceeds the height of the overflow wall. The opening (or the pipe, if a pipe is connected to the overflow basin at the opening) through which the water enters the caisson can be formed by a bottom wall (floor) of the caisson or by a side wall other than the overflow wall and at a level below the overflow section.

[0078] Advantageously, the system may include at least one adjustment means for adjusting the elevation (height) of the overflow section of at least one overflow basin (preferably, the system may include a separate adjustment means for adjusting the elevation of the overflow section of each overflow basin) at least during the installation of the intake system. Indeed, during system installation, some adjustments may be necessary to verify that the system correctly produces the spring water in question and that it minimizes disturbance to the hydrostatic pressure at the outlet of the spring in question. Adjusting the elevation of the outlet (overflow section) of the overflow basin thus improves the performance of the intake system. The elevation adjustment can, for example, be achieved by adjusting the height of the pipe.

[0079] Preferably, the system may include at least one adjustment means for regulating the elevation of the overflow section of at least one overflow basin (preferably the system may include a separate adjustment means for regulating the elevation of the overflow section of each overflow basin) according to variations in flow rates and / or pressure and / or density of the seawater or the water from said source. Adjustable means means that the height can be adjusted at different times during the operation of the source. To this end, the pipeline or overflow basin may have a height-adjustable section; for example, the pipeline or overflow basin may include an extendable or retractable section that can be screwed or unscrewed or moved to adjust the height, or it may include an extendable or retractable section by means of a hydraulic cylinder.The extendable or retractable part can at least slide longitudinally in the pipe to increase or decrease the (vertical) height of the pipe or overflow basin.

[0080] According to a preferred embodiment of the invention, the vertical distance zc between the underwater outlet of the source considered (of each source) and the level (altitude) of the overflow section of the overflow basin associated with the source considered can be determined by the following formula: z c = ρ m ⋅ z s ⋅ g + Δ p ρ s ⋅ g

[0081] With zs being the depth of the considered underwater outlet relative to sea level, p m the density of seawater and p s the density of the water from the said source in question, g the acceleration due to gravity and Δ pthe predetermined overpressure value (greater than or equal to zero and preferably less than 100mbar) which is defined according to the characteristics of the source so that the flow rate of the source does not vary by more than 5%.

[0082] zc thus corresponds to the height of the spring water column produced by the spring in question such that the hydrostatic pressure at the outlet of the spring is equal to the hydrostatic pressure of the seawater column at that level. Therefore, with such a position of the outlet (overflow section) of the overflow basin associated with the spring in question, the hydrostatic pressure is not, or only slightly, altered.

[0083] Adjusting the height of the overflow section of the overflow basin at the time of installation mentioned previously is particularly interesting, for example, if the water produced has a slightly different salinity than that of the source, or if the means of separation is not, or not completely, watertight, for example.

[0084] Adjusting the height of the outlet (overflow section) of the overflow basin at different times of operation mentioned previously is also particularly interesting if the salinity of the source water and / or the produced water changes over time and / or if the sea level changes (climate warming, taking into account tides for example).

[0085] The adjustment and / or setting then allows the overflow section of the overflow basin to be positioned at the altitude that allows the hydrostatic pressure to be maintained (or to alter this pressure very little) at the outlet of the underwater source.

[0086] Advantageously, the overflow section can have a constant level (a constant altitude) all around the overflow wall so that the overflow altitude is well controlled.

[0087] According to one configuration of the invention, at least one water recovery device (preferably the single water recovery device or each water recovery device) may include a pump, of the type a submersible pump, configured to start when the water level in the recovery device exceeds a first predetermined threshold and configured to stop when the water level in the recovery device falls below a second predetermined threshold, the second predetermined threshold being less than or equal to the first predetermined threshold. This pump thus functions as a submersible pump and is intended to supply water from the recovery device to a distribution network or to a storage facility (for example, one laid on land, onshore or offshore, or at sea, preferably floating).

[0088] It is important to note that the pump in the recovery system is not used to convey water from the outlet of the underwater spring to the overflow basin. This pump is used to remove water from the recovery system. Indeed, using such a pump could disrupt the hydrostatic pressure at the spring outlet, which would be contrary to the intended effect of the invention.

[0089] The use of such a lifting pump allows for automatic operation without human intervention.

[0090] According to one embodiment of the invention, the collection system may include a water storage means and a supply conduit to connect the water recovery device to the storage means.

[0091] Thus, the recovery system is used to collect the water coming out of the overflow basin and the water can be conveyed to a larger capacity storage facility, including remotely.

[0092] The storage facility can be placed on land, onshore or offshore, preferably placed on the coast to facilitate access.

[0093] By onshore installation, we mean that part of the storage facility is fixed to the ground at a level higher than sea level.

[0094] By offshore installation, we mean that part of the storage facility is fixed to the ground at a level below sea level and that at least a portion of the storage facility is in contact with seawater.

[0095] Alternatively, the storage method could be floating. For example, it could be a floating balloon that can be towed by a boat. It could also be a floating tank anchored to the seabed by cables (synthetic or metallic) or chains, preferably with taut cables to limit the tank's movement.

[0096] For example, the storage method can be a closed or semi-closed tank, a pond or an artificial lake (corresponding to open tanks).

[0097] The supply line may advantageously include a pump to convey water from the recovery device to the storage means.

[0098] It is important to note that the supply line pump is not used to convey water from the outlet of the underwater spring to the overflow basin, but only to convey water from the recovery device to the storage tank. Indeed, if such a pump were used, the hydrostatic pressure at the spring outlet could be disrupted to such an extent that the flow rate would be reduced by more than 5%, or even stopped altogether, which would be contrary to the intended effect of the invention.

[0099] The supply line pump can be a lift pump of the same type as that of the recovery device.

[0100] Storing water on land makes it easier to store. Furthermore, the stored water is closer to its point of use and / or prior treatment (possible desalination, fungicide treatment, bactericide treatment, etc.).

[0101] Preferably, the storage unit, when floating, is capable of being disconnected from the supply line: in other words, the storage unit includes a means for connecting to and disconnecting from the supply line. Thus, when the storage unit is full, it can be disconnected from the supply line and towed by a boat to shore. Another storage unit can then be connected to the supply line to collect and store the water produced. In this way, there is little or no loss of the water produced.

[0102] The feed conduit can be flexible to facilitate connection / disconnection operations to floating storage media.

[0103] According to one variant, at least one recovery device (at least one device, each of the devices or the single device) may be placed on land, onshore or offshore, preferably on the coast to facilitate access.

[0104] By onshore installation, we mean that part of the recovery device is fixed to the ground which is at a level higher than sea level.

[0105] By offshore installation, we mean that part of the recovery device is fixed to the ground which is below sea level and at least a portion of the recovery device is in contact with seawater.

[0106] According to this variant where at least one recovery device is laid onshore or offshore, this recovery device may include an orifice to allow the introduction of water from an outlet of an additional water source, this orifice allowing the water from the additional water source to enter (penetrate), directly or indirectly, into the recovery device.

[0107] The supplementary water source can be underwater, meaning its outlet is below sea level, or terrestrial, meaning its outlet is above sea level. When the supplementary water source is underwater, the opening in the recovery device is below the water level in that device. When the supplementary water source is terrestrial, the opening in the recovery device can be above the water level in that device.

[0108] Preferably, the outlet of the additional water source can be opposite the orifice, so as to further simplify the system, the water source then being preferentially on the coast, whether terrestrial or underwater.

[0109] Advantageously, at least one recovery device (preferably the single recovery device or each recovery device) may include a control means for maintaining the water level in that recovery device when the orifice is below the water level in that recovery device, such that the pressure generated by the height difference between the water level in that recovery device and the elevation of the outlet of the supplementary water source corresponds to the water pressure of the supplementary water source at its outlet. Thus, by ensuring such a level, the supplementary water source is not, or only minimally, affected by pressure variations induced by the intake system.

[0110] The control means may include a lift pump configured to start when the water level in the recovery device exceeds a first predetermined threshold and configured to stop when the water level in the recovery device falls below a second predetermined threshold, the second predetermined threshold being less than or equal to the first predetermined threshold. The pump may be connected to a float capable of tracking the water level in the recovery device. When the float rises above the first predetermined threshold, the pump starts, and when the float falls below the second predetermined threshold, the pump stops.

[0111] To ensure proper control of the water level in this recovery system, the first and second predetermined thresholds can be close to each other. For example, they can be less than 10 cm apart and preferably identical.

[0112] The use of such a lifting pump allows for automatic operation without human intervention.

[0113] Alternatively, the recovery system can be floating. For example, it could be a floating tank surrounding the overflow basin. This recovery system can be anchored to the ground by cables (synthetic or metallic) or chains, preferably with tensioned cables to limit the movement of the floating tank.

[0114] For example, the recovery device can be a closed, semi-closed or open reservoir, a pond or an artificial lake (corresponding to open reservoirs).

[0115] Storing water in the onshore recovery system makes storage easier. Furthermore, the stored water is closer to its point of use and / or its potential pretreatment (desalination, fungicide treatment, bactericide treatment, etc.). Since the overflow basin is in close proximity to the recovery system (either the recovery system surrounds the overflow basin or they are separated by an overflow wall, for example), a pipe connecting the separation device to the overflow basin may not be straight but follow a curved line. Therefore, a flexible pipe can be advantageously used.

[0116] According to a preferred configuration of the invention, the intake system can be configured to capture water from several underwater sources. The intake system can then comprise as many separation means as there are overflow basins for each underwater source, each separation means being connected to a separate overflow basin. Indeed, to capture water from each of the underwater sources, it is advantageous to have a separate separation means and an overflow basin for each source, so as to avoid interference from one source to another.

[0117] In this configuration, the intake system can include a single water recovery unit to collect water from all the overflow basins simultaneously. This simplifies downstream water treatment and reduces the required infrastructure. Alternatively, the intake system can include multiple water recovery units. Each unit can serve several overflow basins, for example, to collect water with similar salinity or composition to optimize treatment. Each unit can also be connected to a single overflow basin to prevent mixing the different waters.If the composition of water from a source deviates from its initial composition (for example, bacterial pollution, salinity levels or varying chemical composition), using a recovery device connected to a single overflow basin rather than multiple basins allows for faster identification of the source causing the defect, without having to stop water production from other sources.

[0118] The invention also relates to a method for capturing water from at least one underwater source. In this method, at least the following steps are carried out using the capture system as described above: The water from at least one source (preferably from each source) is separated from the seawater at an underwater outlet, by at least one separation means; The water (produced and originating from the underwater source) separated from the seawater is conveyed to the opening in the (each) overflow basin, preferably by a pipe (the length of which is optionally adjustable and preferably adjustable) connecting the separation means to the overflow basin; The speed of the water (from the source) in the overflow basin is slowed down by means of an overflow section of the overflow basin strictly larger than the water passage section in the opening: this makes it possible to reduce the height of the jet of water exiting the overflow basin;The water from the spring contained in the overflow basin is made to overflow through the overflow wall (whose outlet section is above sea level) and the spring water is recovered, by gravity, in the recovery device.

[0119] This process operates without a pump, which avoids any disturbance of hydrostatic pressure at the pump outlet, which could disrupt the flow from the source and / or allow seawater to enter the collection system.

[0120] Preferably, the water from the water recovery device is conveyed, via a supply pipe, to a storage means which may be floating, laid onshore or offshore, and preferably laid on the coast to facilitate operations.

[0121] When water storage is located onshore or offshore, it is as close as possible to the needs of populations, livestock, and / or crops, as well as to water treatment plants before distribution (for example, fungicide, bactericide, and / or desalination). Furthermore, onshore water storage can be easily achieved using a natural or artificial pond, for example. The supply pipeline may include a pump to convey water from the bottom of the collection point to the storage facility, but this pump is not used to raise the water from the source to the overflow basin.

[0122] When floating, the storage unit can be easily towed to the shore where fresh water is needed.

[0123] Alternatively, water can be drawn from an additional water source directly into the (one of the) water recovery device (or storage means) through an orifice in the recovery device (or storage means), the orifice advantageously being opposite the outlet of the second source. This allows for improved water recovery by adding an additional water source.In this case, to avoid disturbing (or minimize disturbing) the hydrodynamic equilibrium, the water level in the water recovery device (or storage container) can be controlled so that the pressure generated by the water height between the water level and the orifice corresponds to the outlet pressure of the supplementary water source or to the sum of the outlet pressure of the supplementary water source and a second predetermined overpressure value (dependent on the supplementary water source) capable of generating a flow variation of less than 5% from this source, particularly when the supplementary water source is underwater. This can be achieved, for example, using a booster pump as previously described, along with a first and second predetermined threshold.

[0124] According to one configuration of the invention, water can be stored in a floating water recovery device, preferably anchored to the ground by tensioned cables.

[0125] Furthermore, according to an advantageous variation of this alternative, the water can be transferred from the floating recovery device to a mobile floating tank, which can then be towed ashore by boat. Alternatively, several mobile floating recovery devices can be used. In this case, it is not necessary to transfer the water from the floating recovery device to a mobile floating tank. Instead, one mobile floating recovery device can be towed directly to shore, and another mobile floating recovery device can be connected to the intake system to collect the water.

[0126] There figure 1 illustrates, schematically and without limitation, a first embodiment of a capture system according to the invention.

[0127] The intake system is used to produce water at outlet S1 from a subsea source. Thus, the subsea source opens into the seawater, at ground level 7 located below sea level 8.

[0128] The capture system includes a separation means in the form of a weighted envelope 1 to be held on the ground 7 and so as to surround the outlet S1 of the underwater source.

[0129] The water from the underwater spring has a lower salinity than seawater and preferably, this water is fresh water (whose salinity is compatible with that of drinking water).

[0130] The collection system also includes a pipe 3, for example a tubular pipe, connecting the casing 1 to the overflow basin 5. The pipe 3 is connected in a watertight manner to the casing 1 and to the overflow basin 5 to prevent any entry of seawater on the one hand and to prevent any loss of spring water on the other.

[0131] Thus, the water exiting outlet S1 of the underwater source arrives in the separation means 1 and then in the conduit 3 before reaching the overflow basin 5.

[0132] The overflow basin 5 is in the form of a concave bowl 30. The inlet cross-section of the concave bowl 30 corresponds to the cross-sectional area of ​​the water passage in the pipe. Due to the shape of the concave bowl 30, the cross-sectional area of ​​the water passage within the bowl gradually increases until it reaches the outlet cross-section, which corresponds to the highest point in the water column, also known as the overflow section. As a result, the water velocity is gradually reduced, thus limiting the height of the water jet and preventing disturbances that could be caused, for example, by a sudden increase in the cross-sectional area.

[0133] The concave bowl 30 forms an overflow wall: the water arriving in the overflow basin 5 is forced to pass over the concave bowl 30, forming the overflow wall, to overflow all around this concave bowl 30.

[0134] When the water passes over the concave bowl 30, it enters directly into the recovery device, consisting here of a recovery basin 4.

[0135] The recovery basin 4 surrounds the overflow basin 5 to collect the water that overflows all around the overflow basin 5.

[0136] Recovery basin 4 is floating and anchored by tensioned cables 2 which are weighted by weights 6.

[0137] Since the recovery basin 4 is floating, it can slide vertically around the pipe 3, essentially creating a heaving motion. The pipe can be a rigid metal pipe, particularly steel, or a flexible pipe, which allows greater freedom of movement for the floating recovery basin 4. A sealing device is positioned at the interface between the recovery basin 4 and the pipe 3. Because the salinity of the spring water is lower than that of seawater, the level of the overflow section (outlet) of the overflow basin 5 is above sea level 8, such that the water column pressure from the spring outlet S1 to the outlet section 99 of the overflow basin is equal to or substantially equal to the hydrostatic pressure of the seawater between the spring water outlet S1 and sea level 8.

[0138] There figure 11illustrates, schematically and without limitation, a top view of the water intake system of the figure 1 .

[0139] Water arrives in pipe 3 through the opening leading into the overflow basin, which here consists of a concave bowl 30. Thus, the section of the opening is defined by the internal section of pipe 3, which is cylindrical here.

[0140] The water can then reach the concave bowl 30 where the water passage cross-section increases. At the outlet of the concave bowl, at the overflow point, the cross-section is the internal cross-section of the concave bowl 30. This outlet cross-section, or overflow cross-section 9, is shown in the figure by the slanted continuous hatching. It can thus be observed that this overflow cross-section 9 is larger than the cross-section of the opening.

[0141] Furthermore, when the water passes over the overflow wall formed by the concave bowl 30, it reaches the recovery device 4.

[0142] In the recovery device 4, the water passage section is delimited between the concave bowl 30 and the external wall of the water recovery device 4. In the figure, this section is materialized by the area hatched by dots.

[0143] There figure 2 illustrates, in a schematic and non-limiting way, several modes of operation of the capture system.

[0144] In these diagrams a), b), c) and d), the intake system includes a separation means on which a non-return valve 10 is fitted to prevent seawater from entering the intake system and to evacuate the potential excess of spring water, a pipe and an overflow basin 5 with an overflow section level 9 of the overflow basin 5 and a recovery device in which the water 12 that has overflowed from the overflow basin is found.

[0145] In diagram a) on the left, the pressure at outlet S1 of the spring is lower than that which would be generated by a column of water flowing from outlet S1 of the spring to the level of outlet section 9 of overflow basin 5. The water level 11 in overflow basin 5 is therefore below the level of overflow section 9 of overflow basin 5. In this case, the flow from the spring is reversed. In other words, there is a transfer of water from the intake system to the spring. This operation could occur occasionally and only for a short period. The water column would then drop to a level close to sea level and remain filled with spring water. When the pressure returns to its usual level, the intake system would then refill with water up to the overflow basin.

[0146] The non-return valve 10 is closed to prevent seawater from remaining in the intake system and in the source.

[0147] Diagram b) represents an operating condition where the source pressure is equal to or approximately equal to that which would be generated by a column of water flowing from the source outlet S1 to the overflow section 9 of the overflow basin 5. In this case, a low flow rate occurs from the source. The non-return valve 10 can then be kept closed. The water flow rate produced then corresponds to the flow rate of the source.

[0148] Diagram c) represents an operating scenario where the spring pressure is greater than that which would be generated by a column of water flowing from the spring outlet S1 to the overflow section 9 of the overflow basin 5. In this case, the spring flow rate is higher than that shown in diagram b). If the flow rate is too high to pass through the intake system, the non-return valve 10 will open to allow some of the spring water to be discharged into the seawater.

[0149] Preferably, the opening of this non-return valve can be controlled to maintain a substantially constant flow rate in the intake system. In other words, the non-return valve 10 will be opened more or less to control the flow rate.

[0150] Alternatively, the opening of this non-return valve 10 is not controlled but pressure-controlled as explained earlier in the description. In this case, the non-return valve 10 limits the pressure in the separation unit, allowing a slight overpressure of a predetermined value (a few millibars, preferably less than 100 mbar) in the separation unit, thus ensuring maximum flow.

[0151] Diagram d) represents an operating scenario where the spring pressure is much higher than that which would be generated by a column of water flowing from the spring outlet S1 to the overflow section 9 of the overflow basin 5. In this case, the spring flow rate is greater than that shown in diagram c), and a water jet 13, indicated by the dark gray arrow, erupts above the overflow basin. Because the flow rate is too high to pass through the intake system, the non-return valve 10 is fully open to allow some of the spring water to be discharged into the seawater.

[0152] The height of jet 13 can be limited by widening the water passage section between the pipe and the outlet section of the overflow basin 5.

[0153] There figure 3illustrates, schematically and without limitation, a second embodiment of the capture system according to the invention.

[0154] The intake system is used to produce water at outlet S1 from a subsea source. Thus, the subsea source opens into the seawater, at ground level 7 located below sea level 8.

[0155] The intake system includes a weighted separation means to be kept watertight on the ground 7 and to surround the outlet S1 of the underwater spring. The water from the underwater spring has a lower salinity than seawater and preferably, this water is fresh water (with a salinity compatible with that of drinking water).

[0156] The collection system also includes a pipe 3, for example a tubular pipe, connecting the separation means to an overflow basin with an overflow section 9. The pipe 3 is connected in a watertight manner to the separation means and to the overflow basin 5 to prevent any entry of seawater on the one hand and to prevent any loss of spring water on the other.

[0157] Furthermore, the level of the overflow section 9 of the overflow basin is adjustable by means of an extendable / retractable part 14 which serves as an interface between the overflow basin and the pipe 3. As shown, the extendable / retractable part 14 is a part of the pipe 3 which can slide within the pipe 3 to allow for lengthening or shortening of the pipe 3. Of course, to ensure watertightness, a sealing means is positioned between the pipe 3 and the extendable / retractable part 14.

[0158] Thanks to the extendable / retractable part 14, it is possible to modify the height Zc between the outlet S1 of the underwater source and the level of the outlet section 9 of the overflow basin and thus adapt to variations in the source parameters, without generating (or generating little) hydrostatic disturbances.

[0159] Thus, the water exiting outlet S1 of the underwater source arrives in the separation means and then in pipe 3 before reaching the overflow basin.

[0160] The overflow basin is in the form of a concave bowl identical to that of the figure 1 .

[0161] The concave bowl forms an overflow wall: the water arriving in the overflow basin is forced to pass over the concave bowl, forming the overflow wall, to overflow all around this concave bowl.

[0162] When the water passes over the concave bowl, it enters directly into the recovery device, consisting here of a recovery basin 4.

[0163] Recovery basin 4 surrounds the overflow basin to collect the water that overflows all around the overflow basin.

[0164] Recovery basin 4 is floating and anchored by tensioned cables 2 which are weighted by KG weights.

[0165] Because the recovery basin 4 is floating, it can slide vertically around the pipe 3, essentially creating a heaving motion. The pipe 3 can be a rigid metal pipe, particularly steel, or a flexible pipe, which allows for greater freedom of movement for the floating recovery basin 4. A sealing device is positioned at the interface between the recovery basin 4 and the pipe 3.

[0166] Since the salinity of the spring water is lower than that of the sea water, the level of the overflow section 9 of the overflow basin is above sea level 8, so that the pressure of the water column from the outlet S1 of the spring to the level of the overflow section of the overflow basin 9 is equal or substantially equal to the hydrostatic pressure of the sea water over the height Z s between the outlet S1 of the spring water at sea level 8.

[0167] The collection system also includes a supply conduit 15 equipped with a pump 16 to convey water from the recovery device 4 to the mobile floating tank 20.

[0168] When the mobile floating tank 20 is full, it is towed by a boat to the shore and another mobile floating tank 20 is then connected to the supply conduit 15.

[0169] Thus, the mobile floating tanks are suitable for being connected and disconnected from the supply conduit 15.

[0170] There figure 4 illustrates, schematically and without limitation, a third embodiment of the capture system according to the invention.

[0171] The intake system is used to produce water at outlet S1 from a subsea source. Thus, the subsea source opens into the seawater, at ground level 7 located below sea level 8.

[0172] The capture system includes a weighted separation means to be kept watertight on the ground 7 and to surround the outlet S1 of the underwater source.

[0173] The water from the underwater spring has a lower salinity than seawater and preferably, this water is fresh water (whose salinity is compatible with that of drinking water).

[0174] The collection system also includes a pipe 3, for example a tubular pipe, connecting the separation means to an overflow basin with an overflow section 9. The pipe 3 is connected in a watertight manner to the separation means and to the overflow basin to prevent any entry of seawater on the one hand and to prevent any loss of spring water on the other.

[0175] Furthermore, the level of the overflow section 9 of the overflow basin is adjustable by means of an extendable / retractable part 14 which serves as an interface between the overflow basin and the pipe 3. As shown, the extendable / retractable part 14 is a part of the pipe 3 which can slide within the pipe 3 to allow for lengthening or shortening of the pipe 3. Of course, to ensure watertightness, a sealing means is positioned between the pipe 3 and the extendable / retractable part 14.

[0176] Thanks to the extendable / retractable part 14, it is possible to modify the height Zc between the outlet S1 of the underwater source and the level of the outlet section 9 of the overflow basin and thus adapt to variations in the source parameters, without generating (or generating little) hydrostatic disturbances.

[0177] Thus, the water exiting outlet S1 of the underwater source arrives in the separation means and then in pipe 3 before reaching the overflow basin.

[0178] The overflow basin is in the form of a concave bowl identical to that of the figure 1 The concave bowl forms an overflow wall: the water arriving in the overflow basin is forced to pass over the concave bowl, forming the overflow wall, to overflow all around this concave bowl.

[0179] When the water passes over the concave bowl, it enters directly into the recovery device, consisting here of a recovery basin 4.

[0180] Recovery basin 4 surrounds the overflow basin to collect the water that overflows all around the overflow basin.

[0181] Recovery basin 4 is floating and anchored by tensioned cables which are weighted by KG weights.

[0182] Since the recovery basin 4 is floating, it can slide vertically around the pipe 3, essentially creating a heaving motion. The pipe 3 can be a rigid metal pipe, particularly steel, or a flexible pipe, which allows greater freedom of movement for the floating recovery basin 4. A sealing device is positioned at the interface between the recovery basin 4 and the pipe 3. As the salinity of the spring water is lower than that of seawater, the level of the overflow section 9 of the overflow basin is above sea level 8, such that the pressure of the water column from the spring outlet S1 to the overflow section 9 of the overflow basin is equal to or substantially equal to the hydrostatic pressure of the seawater over the height Zs between the spring water outlet S1 and sea level 8.

[0183] The collection system also includes a supply conduit 15 equipped with a pump 16 to convey water from the recovery basin 4 to the land-based coastal reservoir (laid on the ground onshore near the coast) 21.

[0184] The terrestrial coastal reservoir can be an artificial reservoir or a natural space such as a lake or pond.

[0185] On the figures 1 , 3, and 4 Pipe 3 is preferably rigid, long, and vertical to simplify the intake system and make it more compact. The intake systems shown in these figures are for the intake of a single underwater water source and therefore include only one separation device, one overflow device, and one water recovery device.

[0186] There figure 5 illustrates, schematically and without limitation, a fourth embodiment of the capture system according to the invention.

[0187] The intake system is used to produce water at outlet S1 from a subsea source. Thus, the subsea source outlet S1 discharges into the seawater at ground level below sea level 8. The subsea outlet S1 could nevertheless emerge on the coast at an altitude below sea level but above the seabed.

[0188] The collection system includes a weighted separation means 1, designed to be held securely in place on the ground 7 and to surround the outlet S1 of the underwater spring. The water from the underwater spring has a lower salinity than seawater and is preferably freshwater (with a salinity compatible with that of drinking water).

[0189] The intake system also includes a pipe 3, for example a tubular pipe, connecting the separation unit 1 to an overflow basin 5 with an overflow cross-section 9. The pipe 3 is sealed to both the separation unit 1 and the overflow basin 5 to prevent seawater ingress and to avoid any loss of spring water. The pipe 3 is flexible.

[0190] Furthermore, the level of the overflow section 9 of the overflow basin 5 is adjustable by means of an extendable / retractable part 14 which serves as an interface between the overflow basin 5 and the pipe 3. As shown, the extendable / retractable part 14 is a portion of the pipe 3 that can slide within the pipe 3 to allow for lengthening or shortening of the pipe 3. Naturally, to ensure watertightness, a sealing means is positioned between the pipe 3 and the extendable / retractable part 14.

[0191] Thanks to the extendable / retractable part 14, it is possible to modify the height Zc1 between the outlet S1 of the underwater source and the level of the overflow section 9 of the overflow basin and thus adapt to variations in the parameters of the outlet source S1, without generating (or generating little) hydrostatic disturbances.

[0192] Thus, the water exiting outlet S1 of the underwater source arrives in the separation means 1 and then in the conduit 3 before reaching the overflow basin 5.

[0193] The overflow basin 5 is in the form of a concave bowl identical to that of the figure 1 .

[0194] The concave bowl forms an overflow wall: the water arriving in the overflow basin 5 is forced to pass over the concave bowl, forming the overflow wall, to overflow all around this concave bowl.

[0195] When the water passes over the concave bowl, it enters directly into the recovery device, consisting here of a recovery basin 4.

[0196] The recovery basin 4 surrounds the overflow basin 5 to collect the water that overflows all around the overflow basin 5.

[0197] Recovery basin 4 is located on the coast here offshore since part of recovery basin 4 is below sea level 8.

[0198] Recovery basin 4 includes an outlet opposite the outlet S2 of an additional water source. The outlet S2 of the additional water source is coastal. It is located here at an altitude below sea level 8, which is why recovery basin 4 is offshore. If the outlet S2 of the second source were above sea level, recovery basin 4 could be either onshore or offshore.

[0199] The height Zc2 between the water level in the recovery basin 4 and the outlet S2 of the additional water source (or the orifice of the recovery basin 4) is controlled so as not to disturb (or to disturb little) the hydrostatic balance of the additional water source.

[0200] The water level in the recovery basin 4 is controlled so that the pressure of the water column of height Zc2 is equal or substantially equal to the hydrostatic pressure of the seawater column between the outlet S2 of the additional water source and the sea level 8.

[0201] There figure 6 illustrates, schematically and without limitation, a fifth embodiment of the capture system according to the invention.

[0202] The intake system is used to produce water at outlet S1 from a first underwater source and to produce water at outlet S3 from another underwater source (water could also be produced from additional underwater sources). Thus, the first underwater source discharges into seawater via outlet S1, at ground level 7 located below sea level 8, while the source discharged via outlet S3 is a coastal underwater spring. The underwater outlet S1 could, however, discharge onto the coast at an altitude below sea level but above the seabed.

[0203] The capture system includes two separation means 1, one being weighted to be held securely on the ground 7 so as to surround the outlet S1 of the underwater source and the other being held around the outlet S3 of the other source.

[0204] Each of the two means of separation 1 serves to isolate the water from each source from the surrounding seawater.

[0205] The spring waters exiting through outlets S1 and S3 have lower salinities than seawater and preferably, these waters are fresh waters (whose salinity is compatible with that of drinking water).

[0206] Each separation means 1 is connected to a pipe 3, for example a tubular pipe, linking a separation means 1 to a separate overflow basin 5 with an overflow cross-section 9 (corresponding to the outlet cross-section at the top of the overflow wall). Each pipe 3 is watertightly connected to a separate separation means 1 and a separate overflow basin 5 to prevent any ingress of seawater on the one hand and to prevent any loss of spring water on the other. Each pipe 3 is flexible to allow for the relocation of the overflow basins and the water recovery system to the coast.

[0207] Furthermore, the level of the overflow section 9 of each overflow basin 5 is adjustable by means of an extendable / retractable part 14 which serves as an interface between the overflow basin 5 and the pipe 3 to which it is connected. As shown, the extendable / retractable part 14 is a section of the pipe 3 that can slide within the pipe 3 to allow for lengthening or shortening of the pipe 3. Naturally, to ensure a watertight seal, a sealing means is positioned between the pipe 3 and the extendable / retractable part 14.

[0208] Thanks to the extendable / retractable part 14, it is possible to modify the heights Zc1 and Zc3 respectively between the outlet S1 of the subsea source and the level of the overflow section 9 of the overflow basin 5 associated with outlet source S1 and between the outlet S3 of the other subsea source and the level of the overflow section 9 of the overflow basin 5 associated with outlet source S3, and in fact, to adapt to the variations of the parameters of each source, without generating (or generating little) hydrostatic disturbances.

[0209] Thus, the water exiting each of the outlet sources S1 and S3 arrives in one of the separation means 1 and then in a conduit 3 before reaching one of the overflow basins 5. The overflow basins 5 are in the form of concave bowls identical to that of the figure 1 , but other forms can also be envisaged in other modes of embodiment.

[0210] The concave bowls of the two overflow means 5 form overflow walls: the water arriving in each overflow basin 5 is forced to pass over the concave bowl, forming the overflow wall, and overflows all around this concave bowl. When the water passes over the concave bowl, it enters directly into the recovery device, which in this case consists of a recovery basin 4 that is common to both overflow basins 5. Thus, the collection system here comprises a single recovery device 4.

[0211] The recovery basin 4 surrounds the two overflow basins 5 to collect the water that overflows all around the overflow basins 5.

[0212] Recovery basin 4 is located on the coast here offshore since part of recovery basin 4 is below sea level 8.

[0213] As illustrated, the overflow sections 9 of the two overflow basins are located at different altitudes and are a function of the salinities and outlet depths of the two sources. Similarly, the cross-sectional area in the concave bowls, at the inlet and outlet, and the cross-sectional area in the conduit, differ depending on the sources, particularly their flow rates and pressures.

[0214] The water level in the recovery basin 4 is maintained below the overflow levels 9 of the two overflow basins 5.

[0215] There figure 7 illustrates, schematically and without limitation, the principle of a lifting pump in the recovery basin 4.

[0216] The collection system includes a pipe 3, an overflow basin 5, a recovery basin 4 and an extendable / retractable part 14 at the interface between the pipe 3 and the overflow basin 5.

[0217] To reach the recovery basin 4, the water must pass over the wall of the overflow basin 5 formed here by the concave bowl.

[0218] Once the water has reached the recovery basin 4, the water can be conveyed via the supply line 15 to a distribution network, a water treatment plant or a storage reservoir.

[0219] A lifting pump 24 is installed in the lower part of the recovery basin 4 at the inlet of the supply pipe 15.

[0220] When the water level N in the recovery basin 4 reaches the Nmax level, the lift pump 24 is started and the water is then discharged into the supply pipe 15.

[0221] When the water level N in the recovery basin 4 reaches the level Nmin (located above the pump so as to keep the pump submerged), the lift pump 24 is stopped so that a minimum water level is maintained in the recovery basin and so that the lift pump does not run at high speed, which could damage it.

[0222] To determine the water level N in the recovery basin 4, the lift pump 24 can be connected to a float 22 which follows the water level in the recovery basin 4. The float can be connected to the lift pump 24 by a cable 23. Thus, the water level in the recovery basin can be determined and the lift pump can be automatically controlled according to this level N.

[0223] The principle described in the recovery basin can also be applied similarly in a water storage facility, with the water then being sent through the pipe to a distribution network, a water treatment plant or another water storage facility.

[0224] There figure 8This illustrates, schematically and without limitation, a slight variant of the invention in which, once the water has passed through the pipe 3 to reach the overflow basin 5, in the shape of a concave bowl, and has reached its overflow section 9, a guiding means 50 is positioned at the outlet of the overflow basin to accompany the water and direct it away from the wall of the overflow basin 5. The guiding means takes the form of a convex wall so that the water falls in drops without running down the wall of the overflow basin 5. This allows for better drainage of the water towards the water recovery device (not shown in the figure but surrounding the concave bowl of the overflow basin).

[0225] There figure 9 illustrates, schematically and without limitation, a sixth embodiment of the capture system according to the invention.

[0226] The intake system is used to produce water at outlet S1 from a subsea spring. Thus, the subsea spring discharges into the seawater at ground level below sea level. The subsea outlet S1 could, however, emerge on the coast at an altitude below sea level (8) but above the seabed.

[0227] The collection system includes a weighted separation means 1, designed to be held securely in place on the ground 7 and to surround the outlet S1 of the underwater spring. The water from the underwater spring has a lower salinity than seawater and is preferably freshwater (with a salinity compatible with that of drinking water).

[0228] The intake system also includes a pipe 3, for example a tubular pipe, connecting the separation unit 1 to an overflow basin 5 with an overflow cross-section 9. The pipe 3 is sealed to both the separation unit 1 and the overflow basin 5 to prevent seawater ingress and to avoid any loss of spring water. The pipe 3 is flexible.

[0229] The overflow basin 5 is here a caisson with an overflow wall 51 which is one of the side walls of the caisson.

[0230] In addition, the level of the overflow section 9 of the overflow basin 5 is adjustable by means of an extendable / retractable part 14 which is part of the overflow wall 51.

[0231] Thanks to the extendable / retractable part 14, it is possible to modify the height Zc1 between the outlet S1 of the underwater source and the level of the overflow section 9 of the overflow basin 5 and thus adapt to variations in the parameters of the outlet source S1, without generating (or generating little) hydrostatic disturbances.

[0232] Thus, the water exiting outlet S1 of the underwater source arrives in the separation means 1 then in the conduit 3 before reaching the overflow basin 5 in the form of a caisson.

[0233] When the overflow basin 5 is filled, the water passes over the overflow wall 51 to enter, by gravity, the water recovery device 4 which is separated from the overflow basin 5 by the overflow wall 51.

[0234] A pump 24 can be installed in the water recovery device 4 to convey the water to a treatment plant or to a distribution network, for example. This pump 24 can be a lift pump, the operation of which has been described previously.

[0235] Recovery basin 4 is located on the coast here offshore since part of recovery basin 4 is below sea level 8.

[0236] The intake system also includes a separation means for separating the water from a second underwater source S2 and a second overflow means 5. This separation means may consist of a sealed enclosure surrounding the source S2 between the coastal rock face and the overflow basin in the form of a caisson; the seal may be achieved, for example, by mortar or another sealing method. The second overflow means 5 is in the form of a caisson, one side of which forms the overflow wall 51. The overflow basin 5 includes an opening opposite the second (pipeless) outlet source S2. The outlet of the second source S2 is coastal. It is located here at an altitude below sea level 8, which is why the recovery basin 4 is offshore.

[0237] Thus, the water coming out of outlet S2 of the underwater source arrives in the separation means and then directly into the overflow basin 5 in the form of a caisson.

[0238] When the overflow basin 5 is filled, the water passes over the overflow wall 51 to enter, by gravity, the water recovery device 4 which is separated from the overflow basin 5 by the overflow wall 51.

[0239] The recovery basin 4 is common to the two overflow basins 5: it recovers the water from these two overflow basins 5.

[0240] The height Zc2 between the overflow section 9 of the second overflow means 5 and the outlet S2 of the second source is controlled so as not to disturb (or to disturb little) the hydrostatic equilibrium of the second outlet source S2.

[0241] The water level in recovery basin 4 is controlled so that it is kept below the level of the lowest overflow section, the two overflow sections not necessarily being at the same level and presumably being at different levels.

[0242] There figure 10 illustrates, schematically and without limitation, a seventh embodiment of a capture system according to the invention.

[0243] The figure on the left is a front view while the view on the right is a side view of the same system.

[0244] The catchment system includes several overflow basins 140 (here six overflow basins) in the form of parallelepiped caissons to facilitate the arrangement of the caissons.

[0245] Each overflow basin 140 includes an opening A1, A2, A3, A4, A5, A6 for the inlet of water from a separate source. Each overflow basin 140 is connected, via these openings A1, A2, A3, A4, A5, A6, to a separation means (not shown) directly or indirectly by means of a pipe, the separation means surrounding each source separately.

[0246] As shown in the figures, openings A1, A2, A3, A4, A5, and A6 each open onto a side wall of each caisson (the side wall opposite the overflow wall 130), in the lower part of the side wall (and below the overflow section 135). However, these openings could open onto the lower wall of the caisson, as with opening A3b shown for illustrative purposes.

[0247] When the water reaches the overflow section 135, whose level corresponds to the upper level of the overflow wall 130 of each caisson, the water flows over the overflow wall 130 to reach the water recovery device 150, which is common to all the overflow basins. Alternatively, several water recovery devices 150 could be used, either exclusively for a single overflow basin (in which case there would be as many water recovery devices as overflow basins) or shared by several overflow basins (for example, for waters with very similar salinity or mineral content).As represented, the collection system comprises a single parallelepiped water recovery device 150 whose maximum water level 120 is maintained below the level of the lowest overflow wall (in this case the overflow wall corresponding to the source entering through the opening A1 on the diagram).

[0248] The water recovery unit 150 also includes an orifice O1 for water recovery from an additional source. This orifice O1 is located above the maximum water level 120 in the water recovery unit 150. This orifice O1 is suitable for onshore sources whose outlet is located above sea level.

[0249] Thus, the collection system can include an enclosure 100. The enclosure 100, for example here parallelepiped, includes the various overflow means 140 and the water recovery device(s) 150.

[0250] The water recovery device 150 includes a pipe 15 for supplying a distribution network and / or a water treatment plant. This pipe includes a pump 24, which is a lift pump. A float 22 is connected to the pump 24 by a cable 23 so as to monitor the water level in the water recovery device 150. When the water level in the water recovery device 150 reaches a first predetermined threshold, the pump 24 is started to discharge the water; when the water level in the water recovery device 150 reaches a second predetermined threshold, below or equal to the first threshold, the pump is stopped to maintain a sufficient water level in the water recovery device 150, ensuring that the pump remains submerged to prevent it from losing its prime and to prevent it from running at high speed, which could damage it.

[0251] As can be seen in the diagram on the left, the parallelepiped caissons of the 140 overflow basins are not identical, firstly because the height of the overflow walls differs for each 140 overflow basin, and secondly because the widths of the caissons, such as widths L2, L3, and L4, can vary. These widths can vary, in particular, depending on the nominal flow rates of the different sources.

[0252] The caissons of the overflow basins 140 are separated from the water recovery device 150 each by an overflow wall 130.

[0253] The side walls 110 of the caissons of the overflow basins 140, other than the overflow wall 130, rise to the upper level 160 (the ceiling) of the enclosure 100, so that the water of an overflow basin 140 cannot pass into another overflow basin 140 by passing over a side wall 110.

[0254] According to an alternative where the enclosure would have no ceiling, the side walls 110 of the caissons of the overflow basins 140, other than the overflow wall 130, rise to a certain defined level higher than that of all the overflow walls.

[0255] By arranging the various overflow basins 140 and the water recovery device(s) 150 within an enclosure 100, the footprint of the catchment system is reduced, which is beneficial for the environment. Furthermore, greater flexibility can be introduced into the system's design and manufacturing.

[0256] In the illustration of the figure 10All the overflow basins 140 are positioned on one side of the water recovery device 150, but of course, the overflow basins 140 could be placed on two, three, or four sides of the parallelepiped-shaped water recovery device. If the overflow basin caissons and / or the water recovery device(s) are not parallelepiped-shaped, other arrangements of these elements within an enclosure could, of course, be considered.

[0257] There figure 12 This schematically and non-limitingly illustrates a top view of a catchment system where the overflow basin 5 is formed by a caisson, here parallelepiped-shaped. The caisson includes an overflow wall 130 which separates the overflow basin 5 from the recovery device 4.

[0258] The water arrives at the bottom of the caisson of the overflow basin 5 at the level of the opening through the pipe 3.

[0259] The section of the opening through which the water arrives from pipe 3 is thus delimited by the internal section of pipe 3, here cylindrical.

[0260] The overflow section 9 is delimited by the walls of the overflow basin 5, including the overflow wall 130. It can thus be observed that this overflow section 9 is larger than the section at the opening corresponding to the internal section of the pipe 3. This overflow section 9 is shown on the figure by the hatching in continuous inclined lines.

[0261] Furthermore, when the water overflows and reaches the water recovery device 4, the water is in the section delimited by the walls of the water recovery device 4, including the overflow wall 130. This section is shown in the figure by the area hatched with dots.

Claims

1. System for collecting water from at least one subsea water source comprising at least one separation means (1) for separating the water from the at least one source from sea water, each separation means (1) being connected to a separate overflow basin (5), each overflow basin (5) comprising an opening (A1, A2, A3, A4, A5, A6) for the inlet of water from the at least one source, the collecting system comprising at least one water recovery device (4, 150), each overflow basin (5) comprising an overflow wall (51, 130) configured such that water from the at least one source passes over said overflow wall (51, 130) to enter, under the effect of gravity, the at least one recovery device (4, 150) within each overflow basin (5), the overflow cross section (9, 135) of said overflow basin (5) being strictly greater than the cross section of said opening (A1, A2, A3, A4, A5, A6) of said overflow basin (5), characterized in that the overflow cross section (9, 135) of the overflow basin is located strictly above sea level (8).

2. System for collecting water from at least one subsea water source according to Claim 1, wherein each separation means (1) is connected to the opening (A1, A2, A3, A4, A5, A6) of the overflow basin (5) by a pipe (3), the flow cross section for the flow of water along each pipe (3) being strictly smaller than the maximum flow cross section for the flow of water in the separation means (1) to which the pipe (3) is connected and in the maximum flow cross section for the flow of water in the overflow basin (5) to which the pipe (3) is connected.

3. System for collecting water from a subsea water source according to one of the preceding claims, wherein the at least one separation means (1) comprises a shroud, preferably a flexible shroud.

4. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one separation means (1) comprises at least one non-return valve (10) capable of allowing the water from said source to pass to outside the separation means (1) and of preventing the passage of sea water towards the inside of the separation means (1).

5. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein said overflow wall (51, 130) of at least one overflow basin (5) is in the form of a concave bowl (30), the opening of this at least one overflow basin (5) being positioned at the bottom of the concave bowl (30), the recovery device (4) preferably surrounding the concave bowl (30).

6. System for collecting water from at least one subsea water source according to one of Claims 1 to 4, wherein at least one overflow basin (5) is formed by a caisson comprising the overflow wall (130), the overflow wall (130) separating the overflow basin (5) on one side of the overflow wall (130) from the recovery device (4) on the other side of the overflow wall (130).

7. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the system comprises adjusting means for adjusting the height of the overflow cross section (9, 135) of at least one overflow basin (5) at least at the time of installation of the collecting system, the system preferably comprising adjustment means for adjusting the height of the overflow cross section (9, 135) of at least one overflow basin (5) as a function of variations in flow rates and / or pressures and / or variation in the density of the sea water or of the water of the at least one source.

8. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the vertical distance zc between the outlet of each subsea source and the level of the overflow cross section (9, 135) of each overflow basin (5) to which said outlet is connected is determined using the following formula: z c = ρ m ⋅ z s ⋅ g + Δ p ρ s ⋅ g where zs is the depth of the outlet (S1, S2, S3) of the relevant subsea source relative to sea level (8), g is the acceleration due to gravity, Δp is a predetermined overpressure value greater than or equal to zero and defined as a function of the characteristics of the relevant source, ρm is the density of the sea water and ρs is the density of the water of said relevant subsea source.

9. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one recovery device (4) includes a pump (24) configured to be turned on when the water level in the recovery device (4) exceeds a first predetermined threshold and configured to be turned off when the water level is below a second predetermined threshold, the second predetermined threshold being less than or equal to the first predetermined threshold.

10. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the collecting system comprises a water storage means and a supply pipe (15) connecting the at least one water recovery device (4) to the storage means, the storage means being floating, and preferably capable of being disconnected from the supply pipe, or placed on the ground.

11. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one water recovery device (4) is floating and anchored to the ground by cables, preferably by tensioned cables, or placed on the ground onshore or offshore.

12. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one water recovery device (4) comprises an orifice for allowing the introduction of water from an outlet (S2) of an additional water source, the orifice allowing water from said additional water source (S2) to enter the at least one water recovery device (4) directly or indirectly, the at least one recovery device (4) preferably comprising control means for controlling the water level in the at least one water recovery device when the orifice is below the water level.

13. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the collecting system is configured to collect water from a plurality of subsea sources, said collecting system comprising as many separation means (1) and overflow basins (5) as there are sources, each separation means (1) being connected to a separate overflow basin (5), the collecting system preferably comprising a single water recovery device (4) for recovering water from all the overflow basins.

14. Method for collecting water from at least one subsea water source, wherein at least the following steps are carried out using the collecting system according to one of Claims 1 to 13: - Water from the at least one source is separated from the sea water at a subsea outlet by the at least one separation means (1); - The water separated from the sea water is conveyed to the opening (A1, A2, A3, A4, A5, A6) in the overflow basin (5); - The speed at which the water flows in the overflow basin (5) is slowed down by means of an overflow cross section (9, 135) of the overflow basin (5) that is strictly greater than the flow cross section for the flow of the water through the opening (A1, A2, A3, A4, A5, A6); - The water is caused to overflow from the overflow basin (5) and the water is recovered under the effect of gravity in the recovery device (4), the recovery device (4) being floating or placed on the ground, onshore or offshore, and then, preferably, the water is transferred from the water recovery device (4) to a floating storage means and the floating water storage means is towed to land by a boat.