A CLOSED CAGE TYPE AQUACULATION DEVICE, COMPRISING INTERLOCKING RING STRUCTURES CONNECTED BY PORTIONS OF MEMBRANE IN THE SHAPE OF HYPERBOLOIDS OF REVOLUTION

Abstract

The aquaculture rearing device (1) is of the closed cage type and can be folded for storage or transport, or unfolded for use. It comprises: - at least four annular structures (2) of different diameters, which fit together when the device is folded; - at least three membrane portions (7), impermeable to water, each connecting two consecutive annular structures and following one another in a watertight manner, each of these membrane portions having the shape of a segment of a hyperboloid of revolution when the device is unfolded; and - a sealing element, preferably removable, which closes the device at the bottom (13). All of these membrane portions together define a central hollow volume suitable for holding water and serving as an aquaculture rearing area. Figure for the abstract: Fig 1

Description

Title of the invention: CLOSED CAGE TYPE AQUACULATION DEVICE, COMPRISING INTERLOCKING ANNULAR STRUCTURES CONNECTED BY PORTIONS OF MEMBRANE IN THE SHAPE OF HYPERBOLOIDS OF REVOLUTION technical field

[0001] The present invention relates to an aquaculture farming device of the closed cage type, usable for example for fish farming in marine, river or lake environments.

[0002] This type of device makes it possible to create a closed rearing area, preferably large and, for example, with a capacity of several tens of thousands of cubic meters, which can be directly installed in the natural aquatic environment, while remaining isolated from it. It allows for the growth of algae or the rearing of aquatic animals, such as fish, crustaceans, or mollusks, until they reach a marketable size. Previous art

[0003] In the prior art, open cages were traditionally used for aquaculture. These are large enclosures placed in a natural aquatic environment, such as the sea, a river, a lake, or a pond. This enclosure generally consists of a ring floating on the surface, for example, thanks to a set of buoys, to which a net is attached, serving as the enclosure's wall and having a weighted bottom. Water can thus pass through the mesh of the net, ensuring natural renewal of the water in the enclosure, while the fish raised inside cannot escape.

[0004] Although simple and inexpensive, these open cages have a number of drawbacks. Indeed, because of their open design, they allow for numerous exchanges with the outside environment, which presents risks both for the fish kept inside and for the surrounding environment.

[0005] The fish in the cage can be targeted by predators that manage to slip through the mesh of the net or dive through the open surface, such as gulls. Furthermore, they are not protected from parasites (especially sea lice) and pathogenic microorganisms naturally present in shallow water, to which they are particularly susceptible due to the close quarters inside the cage. This poses a problem of from an animal welfare point of view and represents a significant financial cost for operators due to mortality related to diseases and treatments against them and against parasites.

[0006] Furthermore, the ecosystem outside the cage becomes polluted by the large quantity of effluent from excrement, food debris, and dead fish, which falls outside the cage without being treated, causing a significant increase in local phosphorus and nitrogen concentrations that promote the growth of toxic algae. The surrounding water can also be polluted by chemicals, growth hormones, and antibiotics commonly used in aquaculture.

[0007] Local fish populations can also suffer from contact with caged fish, as diseases and parasites, more common in captive fish due to overcrowding, can spread to wild fish. In the event of accidental damage to nets, for example by predators, farmed fish can also escape and compete with local species for food or disrupt their reproduction and become invasive.

[0008] For all these reasons, more recently, so-called closed aquaculture cages have been developed, which are structures with sealed side and bottom walls. Thus, the rearing area inside the cage and the outside environment are completely isolated from each other, which limits mutual contamination and pollution.

[0009] Enclosed rearing cages allow for significant improvements in farmed fish mortality, as they are better protected from predators and parasites such as sea lice. Furthermore, the water quality and oxygenation levels inside the cage can be controlled, as well as the quantities of feed and treatment products injected into the cage to achieve optimal fish growth.

[0010] Pollution of the external environment is also considerably limited because waste produced inside the cage can be collected and reprocessed and contact between wild and captive fish is avoided.

[0011] The invention falls within the framework of these so-called closed aquaculture breeding cages.

[0012] However, when submerged, these closed cages are subjected to significant mechanical stresses due to the water pressure exerted on their walls, as well as the waves and sometimes very strong currents in the sea or in rivers. To withstand the pressure without collapsing and to maintain their shape despite the waves and currents, conventional closed cages are most often made of very strong, rigid materials, such as concrete or fiberglass. As a result, they are very expensive, extremely heavy, bulky, and cumbersome. They are therefore particularly difficult to store, transport and set up.

[0013] In addition, once set up in their operating location, these cages must be filled with water from the top using pumps, for many hours, before they can be used.

[0014] Closed cages with flexible walls, which are lighter and easier to handle, have also been proposed in the prior art. Thanks to their flexibility, they also have a better capacity to absorb the energy of waves and currents without breaking.

[0015] However, to resist deformation caused by currents and maintain a stable shape with a large internal volume, they must constantly be under positive pressure relative to the surrounding water in which they are immersed. This necessitates filling the cage using a continuously operating pumping system to ensure a greater water level inside the cage than outside, despite the water renewal and circulation required for the well-being of the captive fish, which involves continuously removing some of the water from the cage.

[0016] Furthermore, just like rigid closed cages, these flexible-walled closed cages are placed empty at their operating location and must be filled with water by pumps once installed. However, until the filling is complete and sufficient to ensure internal overpressure, their flexible wall is subjected to movement in the current and waves for hours, risking serious damage as has occurred in the prior art. Description of the invention

[0017] The closed aquaculture cage according to the invention overcomes the disadvantages of its previous flexible-walled devices, without presenting the disadvantages of previous rigid cages.

[0018] Indeed, thanks to the specific configuration of its membrane portions in the form of sections of a hyperboloid of revolution, it has a self-stabilizing shape by gravity when deployed, which allows it to resist the pressure of the surrounding water and the strong stresses related to the swell and the current, without it being necessary to keep it under overpressure.

[0019] In addition, thanks to its interlocking structure, it can advantageously be folded with a limited height when not in use, which greatly facilitates its storage and transport.

[0020] Finally, in the preferred case where it includes a removable sealing element or one that can be opened when the cage is put in place, it is advantageously self-filling. That is to say, when it is put in place, water naturally enters the cage through the opening left by this element. The obturator automatically fills the cage during deployment. This makes filling the cage much faster than with the pumping system used in previous flexible-walled cages, and therefore much less risky for the membrane.

[0021] The invention teaches an aquaculture device of the closed cage type which can be alternatively folded for storage or transport, or deployed for use.

[0022] This device comprises: - at least four annular structures of different diameters, including an upper annular structure, an upper middle annular structure, a lower middle annular structure and a lower annular structure, these structures being nestable within each other in the folded state of the device and being arranged coaxially one above the other in the deployed state of the device; - at least three water-impermeable membrane portions, including an upper membrane portion, a middle membrane portion, and a lower membrane portion, each connecting two consecutive annular structures and following one another in a watertight manner, each of these membrane portions having the shape of a segment of a hyperboloid of revolution in the deployed state of the device; and - a sealing element that closes the device at the bottom.

[0023] The whole of these portions of membrane and of the sealing element delimits a central hollow volume suitable for containing water and for serving as an aquaculture rearing area.

[0024] Thanks to their different diameters, the annular structures can advantageously be placed inside each other in a nested and, for example, concentric manner, when the device is out of the water.

[0025] The portions of membranes which connect the annular structures in pairs can then be inserted between the rings by each being folded on itself, for example substantially in an accordion, and this despite their abundance.

[0026] When placed on a flat surface, the device according to the invention occupies only a limited height due to its interlocking structure. It is thus much less bulky and cumbersome than prior art structures, which greatly facilitates its storage, transport, and handling.

[0027] According to one embodiment of the invention, the upper annular structure, the upper middle annular structure, the lower middle annular structure and the lower annular structure each have, independently of each other, in their principal plane, a circular or polygonal shape or corresponding to a portion of a circle followed by at least one straight segment, but each have a circular fixing interface for the corresponding portions of membranes.

[0028] Annular structures can thus have a general shape that is not perfectly circular, but which can be partially or totally polygonal, by for example to simplify their manufacture or to facilitate their ballasting or to perform an additional function, for example to serve as a berthing side for boats with regard to the upper annular structure.

[0029] They nevertheless retain a circular attachment interface with the membrane, in order to distribute the forces exerted on the membrane homogeneously over its entire circumference. This interface can be directly integrated into the rest of the annular structure or connected to it, for example, by means of a set of variable-length attachment arms adapted to obtain the circular shape of the interface.

[0030] According to one embodiment of the invention, the diameters of the lower median and upper median annular structures are greater than the diameters of the lower and upper annular structures.

[0031] As a result, the lower and upper median annular structures guarantee between them a large central volume, bordered laterally by the portion of the median membrane and thus define a large-sized rearing zone.

[0032] On the contrary, the lower and upper annular structures are advantageously smaller, which allows the upper structure to be less visible on the water surface to limit visual pollution and on the other hand to be less exposed to the impact of waves and surface splashes and to have a lower wind drag.

[0033] Furthermore, the smaller size of the lower annular structure compared to that of the lower middle annular structure creates a downward slope that promotes the natural collection and accumulation of waste produced within the device at the bottom through sedimentation. This waste can then be easily removed, for example by a suction system, thus limiting pollution and keeping the water in the main rearing zone located between the lower and upper middle annular structures clean.

[0034] According to one embodiment of the invention, in use, the upper annular structure and the upper middle annular structure are structures with a density lower than that of water, while the lower middle annular structure and the lower annular structure are structures with a density higher than that of water.

[0035] When placed alone in water, the upper and upper median annular structures are therefore capable of floating and will be defined in the sense of the invention as having positive buoyancy.

[0036] On the contrary, when the lower median and lower annular structures are placed alone in water, they are unable to float and sink. For the purposes of this invention, they will be defined as having negative buoyancy.

[0037] This negative buoyancy can be obtained by the nature of the lower median and lower annular structures, which can be chosen to be sufficiently heavy and dense. in themselves to be intrinsically negatively buoyant.

[0038] It can also be obtained by adding ballast or weights in or on said annular structures. For example, the annular structures can be filled with mineral or metallic aggregates, or concrete or cast iron counterweights can be attached to them, until the desired density value is reached.

[0039] Moreover, the set of these annular structures is preferentially ballastable positively or negatively.

[0040] Thanks to these differences in density between the annular structures, it is possible to guarantee a complete deployment and vertical tensioning of the entire device, each portion of the membrane being fully deployed and vertically tensioned between the two annular structures to which it is connected.

[0041] According to one embodiment of the invention, the portions of membranes are made of textile fabric associated with a polymeric layer.

[0042] The textile fabric can be of any suitable nature. It can be, for example, a fabric, a multiaxial sheet (called Non-Crimp Fabric or NCF in English), a knitted or non-woven textile.

[0043] The polymer layer makes the membrane textile waterproof by sealing the textile's pores or at least limiting their size so that parasites cannot pass through. This layer is, for example, made of PVC or any other suitable polymer. The application of this polymer layer to the textile is carried out, for example, by a polymer coating or composite lamination process.

[0044] According to one embodiment of the invention, the aquaculture farming device further comprises frames or cables which connect at least two annular structures together.

[0045] These cables or armatures can directly connect the two annular structures, which are preferably consecutive, to hold them in position relative to each other and stiffen the device.

[0046] They can also be used to reinforce one or more portions of a membrane. In this case, they are linked or integrated into said portion of the membrane, for example by passing inside one or more tissue sheaths.

[0047] These cables or reinforcements may be metallic or preferably made of high mechanical performance synthetic fibers. For example, they may be links made of very high molecular weight polyethylene fibers (UHMWPE), such as SPECTRA™ fibers marketed by Honeywell or DYNEEMA™ fibers marketed by DSM.

[0048] According to one embodiment of the invention, the aquaculture farming device It also includes a set of anchor lines for securing the device to the underwater seabed. The rearing device according to the invention is thus anchored to the seabed to immobilize it spatially.

[0049] These anchor lines are preferentially fixed to the upper median annular structure, or alternatively for some to the upper median annular structure and for others to the lower median annular structure, which they preferably surround by tying.

[0050] According to one embodiment of the invention, the aquaculture farming device further comprises a feeding machine, which allows captive animals to be fed automatically and in a controlled manner.

[0051] According to one embodiment of the invention, the aquaculture device further comprises at least one pump for supplying the central hollow volume with water drawn from outside the device. It also comprises at least one water outlet located in a portion of the membrane or in the sealing element in order to limit overpressure inside the device. This water outlet is preferably extended by a tube extending outside the portion of the membrane or the sealing element.

[0052] It is thus possible to easily renew the water inside the rearing area, which is very important for the welfare of captive animals.

[0053] According to a preferred variant of this embodiment of the invention, the aquaculture farming device further comprises at least one distribution column which, in the deployed state of the device, is linked to at least one annular structure, preferably the upper annular structure, and which extends into the hollow central volume, this distribution column receiving the water drawn in by the pump and having openings, preferably at different heights, through which said water exits the distribution column to go into the hollow central volume.

[0054] Depending on the variant, the rearing device may include one or more distribution columns, distributed within the central hollow volume to optimally distribute fresh water. These distribution columns may extend vertically or be arranged at an angle.

[0055] According to a preferred embodiment of this embodiment, said openings are equipped with nozzles or injectors which are oriented so as to send said water into the central hollow volume with a rotational movement, and / or, the device may further comprise at least one propeller fixed to a portion of membrane and intended to impart a rotational movement to the water in the central hollow volume.

[0056] Moving the water present in the hollow central volume used as a rearing area is indeed beneficial to the health of captive animals by their allowing them to exercise, which promotes their growth and improves the quality of their flesh.

[0057] According to one embodiment of the invention, the distribution column, or at least one of the distribution columns if the device has several, includes a floating upper part, which preferably contains a feeding machine.

[0058] According to one embodiment of the invention, the distribution column, or at least one of the distribution columns, extends substantially vertically in the hollow central volume and comprises a main tubular part formed of a succession of sections each in the shape of a hyperboloid of revolution.

[0059] Each of these sections thus has a self-stabilizing shape enabling it to resist the pressure of the surrounding water and the stresses due to swell or currents.

[0060] According to one embodiment of the invention, the sealing element is a skirt which extends from the lower part of said distribution column to the lower annular structure.

[0061] This skirt can be flexible or rigid. It is preferably attached in a removable manner to the lower annular structure or to the distribution column, so as to constitute an openable and resealable sealing element. It can thus only be attached once the rearing device has been deployed and filled.

[0062] According to one embodiment of the invention, the lower part of the lower membrane portion and the sealing element are oriented to form downward-sloping ramps that converge towards each other, thus creating a collection and sedimentation zone for the effluent. This collection zone can advantageously be equipped with a recovery gutter and a pumping system for removing the collected waste.

[0063] According to one embodiment of the invention, the sealing element is removable or capable of being opened.

[0064] Thanks to this advantageous preferred configuration of the device according to the invention, it is possible to omit the sealing element or leave it open during the installation and deployment of the aquaculture device. The device can thus be filled directly and automatically, thanks to the natural entry of water into the hollow central volume through the lower annular structure. The sealing element is then installed or closed once the structure is filled and fully deployed.

[0065] Thanks to this preferred arrangement of the invention, the portions of the membrane are automatically filled with water as soon as they are deployed and are quickly protected from current and pressure by their self-stable hyperboloid shape of revolution.

[0066] According to one embodiment of the invention, the aquaculture farming device includes another sealing element which closes the device in the upper part.

[0067] This upper sealing element thus forms a cover on top of the aquaculture farming device, which is preferably removable or capable of being opened and closed.

[0068] Thanks to this upper sealing element, it is possible to protect the fish contained in the cage from gulls or other birds or predators that might pass through the top of the cage. It also prevents surface water, which may contain parasites, particularly sea lice, from passing over the upper annular structure and entering the central hollow volume where the farmed fish are located, due to swells or surface splashes.

[0069] This upper sealing element also allows the upper part of the cage to be sealed watertight if the aquaculture device is to be completely submerged. It is thus completely invisible from the surface and does not generate any visual pollution. Furthermore, it is thus protected from the turbulence and inclement weather of the surface area, which is the most agitated zone. Brief description of the figures

[0070] Other features and advantages of the invention will become apparent from the following detailed description, which is made with reference to the accompanying drawings, in which:

[0071] [Fig.1] [Fig.1] is a side perspective view of an example of an aquaculture farming device according to the invention in the deployed state;

[0072] [Fig.2] [Fig.2] is a top perspective view of the breeding device aquaculture of the [Fig.l];

[0073] [Fig. 3] [Fig. 3] is a schematic longitudinal cross-sectional view of another example of an aquaculture farming device according to the invention in the deployed state, this device comprising a distribution column;

[0074] [Fig.4] [Fig.4] is a schematic enlargement of the detail circled in [Fig.3] in which a piece of membrane has not been shown to make visible the reinforcing cable integrated into the membrane;

[0075] [Fig. 5] [Fig. 5] is a schematic side view of the aquaculture farming device [Fig.1] in the folded state, the portions of membrane not being shown. Detailed description of the invention

[0076] The aquaculture farming device according to the present invention will now be described in detail with reference to Figures 1 to 5. The equivalent elements shown in the different figures will bear the same numerical references.

[0077] As stated previously, the aquaculture farming device 1 comprises a set of annular structures 2, of which there are four in the examples shown, including an upper annular structure 3, a high median annular structure 4, a low median annular structure 5 and an lower annular structure 6.

[0078] These annular structures 2 are linked in pairs by portions of membrane 7, including a superior portion of membrane 8 disposed between the superior annular structure 3 and the upper middle annular structure 4, a middle portion of membrane 9 disposed between the upper middle annular structure 4 and the lower middle annular structure 5, and a lower portion of membrane 10 disposed between the lower middle annular structure 5 and the lower annular structure 6.

[0079] These membrane portions 7 are waterproof and are joined sequentially at the annular structures 2. They can be made in one piece or joined to each other permanently or temporarily by any suitable means, including sewing, welding (particularly hot welding, high-frequency welding, or ultrasonic welding), stapling, or fastening. Two consecutive membrane portions 7 can also be joined to each other via the annular structure 2 located between them, to which they can be attached. In all cases, the seal of the joint must be ensured, for example, by a fold of fabric covering it.

[0080] Although not shown, the aquaculture device 1 may optionally comprise more than four annular structures 2, and more than three membrane portions 7. When the device is large, it may for example comprise five annular structures 2 and four membrane portions 7, in order to divide the middle membrane portion 9 into two smaller, lighter and easier-to-handle sections.

[0081] The set of these annular structures 2 and these portions of membrane 7 delimits within the device 1 a central hollow volume 11 which can serve as a rearing zone.

[0082] To prevent the water contained in the device and the livestock from escaping, a sealing element 12 closes the device in its lower part 13. It thus plugs the opening 14 in the center of the lower annular structure 6.

[0083] This sealing element 12 can be fixedly attached to the lower membrane portion 10, or preferably in a way that allows it to be opened and closed. It can also be completely removable and preferably put in place once the rearing device 1 is fully deployed and filled with water.

[0084] An example of such a sealing element 12 has been shown in [Fig.3] in the form of a skirt 15 of substantially frustoconical shape.

[0085] Similarly, another sealing element 12 may optionally be provided in the upper part 16 of the device 1 to seal the opening 17 located at center of the upper annular structure 3, especially if it is desired to completely immerse the device 1 or to protect the central hollow volume 11 from any unwanted entry of shallow water due to surface agitation, or to protect livestock from birds.

[0086] As can be seen in Figures 1 to 3, which depict the device in its deployed state, each portion of membrane 7 has the shape of a segment of a hyperboloid of revolution when deployed, i.e., stretched vertically. Thanks to this advantageous shape, which is geometrically very stable, it can withstand the pressure of the water in which it is immersed, surface agitation (swell, waves, splashing, etc.), as well as water currents.

[0087] The hyperboloid shape of revolution of each of these portions of membrane 7 can be more or less marked, that is to say that the neck of the hyperboloid, corresponding to the part of the hyperboloid with the smallest diameter, can be more or less constricted.

[0088] The more the neck of the hyperboloid is narrowed, i.e., the more its diameter is reduced, the more the resistance of the portion of membrane 7 to the various stresses it must withstand (pressure, current, waves, etc.) is improved. But in return, the size of the central hollow volume 11, which serves as a rearing zone, is simultaneously reduced.

[0089] A person skilled in the art will easily be able to find, empirically or by calculation, particularly by iteration, an acceptable compromise between the rearing volume required for the quantity of fish to be raised and the resistance that the membrane must present depending on the importance of the stresses it will have to undergo depending on its location (calm or agitated area, weak or strong currents, depth...).

[0090] Each of the annular structures 2 has a different diameter. In the folded state of the device 1, they can thus be arranged one inside the other like concentric nested structures as shown in [Fig. 5]. The membrane portions 7 (not shown in [Fig. 5]) are folded back on themselves, for example, substantially like an accordion, and fit into the intercalated spaces 18 located between two consecutive annular structures 2. The entire rearing device 1 according to the invention is thus much less bulky and has a limited height. It can therefore be stored and transported much more easily.

[0091] In use, i.e., when the device is immersed, the annular structures 2 are positioned one below the other and the membrane portions 7 are deployed as shown in Figures 1 to 3. The relative densities of the different annular structures 2 are preferably chosen so as to exert a vertical tension on each of the membrane portions 7 so that they are par- fully deployed and thus in the shape of a hyperboloid of revolution.

[0092] Thus, for example, according to a preferred embodiment, the upper annular structure 3 has positive buoyancy so as to be able to float on the surface 19 of the water and ensure the buoyancy of the whole.

[0093] The upper median annular structure 4 and the lower median annular structure 5 have buoyancy values ​​of substantially equal value but opposite directions, the upper median annular structure 4 having positive buoyancy while the lower median annular structure 5 has negative buoyancy. These two annular structures 4 and 5 therefore compensate for each other, while ensuring that the portion of the median membrane 9 is vertically taut.

[0094] The lower annular structure 6 is also negatively buoyant so as to pull the whole device 1 downwards and thus to vertically stretch the lower portion of membrane 10, but also the upper portion of membrane 8 whose end is held on the surface 19 by the upper annular structure 3.

[0095] For the assembly to remain buoyant, the buoyancy value of the upper annular structure 3 must be greater than that of the lower annular structure 6, which is in the opposite direction. More precisely, the balance of masses, buoyancy, and the vertical action of the anchor lines 20 must be maintained.

[0096] But the situation may be different depending on the embodiment. If, for example, it is desired that the aquaculture farming device 1 be completely submerged, a buoyancy value substantially equal to that of the upper annular structure 3, although in the opposite direction, will be chosen for the lower annular structure 6, so that they compensate each other and the whole remains in equilibrium at a chosen depth.

[0097] Once submerged, the aquaculture device 1 is held in position by a set of anchor lines 20 which connect it to the underwater seabed and / or possibly to the bank or shore if it is nearby. These anchor lines 20 are attached to one or more annular structures 2, preferably by going all the way around the circumference of the annular structure concerned using the so-called tying technique.

[0098] In the example shown in the figures, there are four of these anchor lines 20, all of which are attached to the upper median annular structure 4. Of course, many other embodiments are possible.

[0099] As shown in Figures 1 to 4, the device 1 may also include cables 21 which connect two annular structures 2 to each other.

[0100] These cables 21 can have several different functions.

[0101] They can serve to ensure the maintenance and relative positioning of the annular structures 2 with respect to each other, while allowing them sufficient freedom to that they can adapt to the movements of the water, while opposing, for example, their relative rotation. This is, for example, the case of the cables 21a shown in figures 1 and 2 which connect the upper middle annular structure 4 to the upper annular structure 3, going around the upper annular structure 3 according to the cravat technique.

[0102] These cables 21 can also be integrated into the membrane in the manner of a reinforcement, like the cables 21b shown in [Fig. 4], in order to reinforce the relevant portion of the membrane 7. For this purpose, the cables 21b preferably extend into a sheath 22 formed in the membrane 7 and created, for example, by a fold of textile or by the overlap of two adjacent edges 38, the cables 21b thus being held captive by the membrane 7.

[0103] Such reinforcing cables 21 are very useful when the rearing device 1 is intended to be installed in an area where the water is very turbulent or in an area where strong currents are present. Other means of reinforcing the portions of the membranes are also conceivable, instead of or in addition to these cables 21, such as, for example, partial or complete multi-ply construction.

[0104] Furthermore, the use of the reinforcing cables 21 is not necessarily uniform over the entire aquaculture farming device 1. These cables may be limited to the parts subjected to the strongest stresses, or may be more numerous or more robust in these parts, such as for example at the level of the upper membrane portion 8 which is the most severely stressed by surface disturbances.

[0105] On the other hand, by reinforcing the membrane, these cables 21 can also allow the choice of a less resistant membrane, for example less thick or made of a less solid material, but which in return will be less expensive.

[0106] Finally, these cables 21 can also be used to move the annular structures 2 closer together or further apart, respectively to deploy the device during its placement, or conversely to reduce the size of the central hollow volume 11 to facilitate the capture of animals kept inside. This is the case with cable 21c, partially shown in [Fig. 1], which, like a block and tackle and with the help of a set of pulleys 39 distributed around the circumference of the upper 4 and lower 5 median annular structures, allows the lower median annular structure 5 to be raised and brought closer to the upper median annular structure 4 by pulling on cable 21c.

[0107] As illustrated in the embodiment of [Fig.3], the aquaculture farming device 1 may include a distribution column 23 which, in the example shown, extends substantially vertically, in the center of the hollow central volume 11.

[0108] It comprises an upper part 24, which is preferably floating and ballastable, and which is attached to the upper annular structure 3 to ensure its positioning and centering relative to it. The upper part 24 can by example, enclosing a feeding machine 25.

[0109] The distribution column 23 also includes a hollow tubular main part 26, which extends under the floating upper part 24 and over almost the entire height of the aquaculture farming device 1, and which has an opening 27 in the lower part leading outside the aquaculture farming device 1.

[0110] In the example shown, the main tubular part 26 is formed of a succession of membrane sections 28, each in the shape of a hyperboloid of revolution, in order to improve its resistance to crushing and to guarantee the stability of its shape.

[0111] The distribution column 23 is extended by a flexible or rigid skirt 15, which originates from, or is attached to, the lower part of the distribution column 23 and extends radially outwards to the lower annular structure 6 to which it is fixed. This skirt 15 thus constitutes the sealing element 12 which closes the bottom of the hollow central volume 11 of the device 1.

[0112] Advantageously, when attached to the lower annular structure 6, this skirt 15 is oriented so as to form a downward inclined ramp 29 which converges towards the downward inclined ramp 30 formed opposite by the lower part of the lower membrane portion 10, and cooperates with it to create at their junction a circular effluent collection zone 31.

[0113] To ensure the regular renewal of the water contained in the central hollow volume 11, one or more pumps 32 are located in the distribution column 23 and draw in outside water through the opening 27 of the main tubular section 26. As the outside water is drawn from a depth, it is advantageously free of parasites, particularly sea louse. This water rises in the main tubular section 26 of the distribution column 23, from where it is sent through a series of lateral openings 33, preferably equipped with injectors or nozzles, towards the central hollow volume 11 of the device 1.

[0114] These nozzles equipping the lateral openings 33 are preferentially oriented so as to impart a rotational movement to the flow of fresh water (symbolized on [Fig.3] by the thick arrows) exiting the distribution column 23, when it is sent into the central hollow volume 11. This effect is further accentuated by the presence of one or more propellers 35 in the central hollow volume 11, for example distributed on the inner face of certain portions of membrane 7, which allow the water contained in the device 1 to be set in motion.

[0115] In order to avoid any overpressure due to the injection of fresh water into the central hollow volume 11, the device includes one or more water drainage outlets 36 through which the excess water from the central hollow volume 11 is automatically discharged to compensate for the inflow of fresh water, thus ensuring the renewal of the water inside the device.

[0116] These drainage openings 36, preferably equipped with a screen or net to prevent captive animals from escaping, are provided through the membrane sections 7, preferably at an intermediate height of the device 1, so as not to be high enough to allow the entry of parasites present in shallow water, nor low enough to disrupt sedimentation and effluent collection by creating water movement at that level. These drainage openings 36 can thus be placed in the lower part of the middle membrane section 9 and / or in the upper part of the lower membrane section 10 (as in the example shown in [Fig. 3]).

[0117] Each of these drainage outlets 36 is preferentially extended, outside the corresponding portion of membrane 7, by a flexible tube 37, open at its ends, which acts as a valve to open and close this drainage outlet 36 according to the pressure difference between the hollow central volume 11 and the outside of the device 1. When an overpressure exists in the hollow central volume 11, the water passing through the drainage outlet 36 inflates the tube 37 and escapes through the open end of the tube 37. When the pressure decreases, the tube 37 gradually falls back down, until it comes to rest against the portion of membrane 7 when there is no longer any overpressure, thus closing the drainage outlet 36.

[0118] As previously indicated, it can be seen in the figures that the upper median annular structures 4 and lower 5, which are not visible on the surface 19, are those which have the largest diameter in order to guarantee a large volume submerged rearing area.

[0119] In the examples shown, the diameter of the upper median annular structure 4 is larger than that of the lower median annular structure 5. Depending on the variant, the reverse is also possible. However, care must be taken to ensure that the slope of the inclined ramp 30 formed by the lower part of the lower membrane portion 10 is sufficient to achieve satisfactory effluent collection.

[0120] Similarly, in the examples shown the diameter of the upper annular structure 3 is greater than that of the lower annular structure 6, but the reverse can also be considered.

Claims

Demands

1. Aquaculture rearing device (1), of the closed cage type, which can be alternatively folded for storage or transport, or deployed for use, device comprising: - at least four annular structures (2) of different diameters, including an upper annular structure (3), an upper middle annular structure (4), a lower middle annular structure (5) and a lower annular structure (6), these structures being nestable within each other in the folded state of the device (1) and being arranged coaxially one above the other in the deployed state of the device (1);- at least three water-impermeable membrane portions (7), including an upper membrane portion (8), a middle membrane portion (9) and a lower membrane portion (10), each connecting two consecutive annular structures (2) and following one another in a watertight manner, each of these membrane portions (7) having the shape of a segment of a hyperboloid of revolution in the deployed state of the device; and - a sealing element (12) which closes the device (1) at its lower part (13); the whole of these membrane portions (7) and the sealing element (12) delimiting a hollow central volume (11) suitable for containing water and serving as an aquaculture rearing area.

2. Aquaculture farming device (1) according to claim 1, characterized in that in their principal plane the upper annular structure (3), the upper middle annular structure (4), the lower middle annular structure (5) and the lower annular structure (6) each have, independently of each other, a circular or polygonal shape or corresponding to a portion of a circle followed by at least one straight segment, and each have a circular fixing interface for the corresponding portions of membranes (7).

3. Aquaculture farming device (1) according to claim 1, characterized in that the diameters of the lower median annular structure (5) and the upper median annular structure (4) are greater than the diameters of the lower annular structure (6) and the upper annular structure (3).

4. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that, in use, the structure upper annular structure (3) and upper middle annular structure (4) are structures with a density lower than that of water, while the lower middle annular structure (5) and lower annular structure (6) are structures with a density higher than that of water, all of these annular structures (2) being preferentially ballastable.

5. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that the portions of membranes (7) are made of textile fabric associated with a polymer layer.

6. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that it further comprises armatures or cables (21) which connect at least two annular structures (2) to each other.

7. 7. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that it further comprises anchor lines (20) for fixing the device (1) to the underwater ground.

8. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that it further comprises at least one pump (32) for supplying the hollow central volume (11) with water drawn from outside the device (1); and at least one water outlet (36) located in a portion of membrane (7) or in the sealing element (12) in order to limit the overpressure inside the device (1), this water outlet (36) preferably being extended by a tube (37) extending outside the portion of membrane (7) or the sealing element (12).

9. Aquaculture farming device (1) according to the preceding claim, characterized in that it further comprises at least one distribution column (23) which, in the deployed state of the device (1), is linked to at least one annular structure (2), preferably the upper annular structure (3), and extends into the hollow central volume (11), this distribution column (23) receiving the water drawn in by the pump (32) and having openings (33) through which said water exits the distribution column (23) to go into the hollow central volume (H).

10. 10. Aquaculture farming device (1) according to the preceding claim, characterized in that the openings (33) are equipped with nozzles (34) oriented so as to send said water into the hollow central volume (11) with a rotational movement and / or in that the device further includes at least one propeller (35) fixed to a portion of membrane (7) and designed to impart a rotational movement to the water in the central hollow volume (11).

11. 11. Aquaculture farming device (1) according to claim 9 or 10, characterized in that said distribution column (23) comprises a floating upper part (24), which preferably contains a feeding machine (25).

12. 12. Aquaculture rearing device (1) according to any one of claims 9 to 11, characterized in that said distribution column (23) extends substantially vertically in the hollow central volume (11) and comprises a main tubular part (26) formed of a succession of membrane segments (28) each in the shape of a hyperboloid of revolution.

13. 13. Aquaculture rearing device (1) according to any one of claims 9 to 12, characterized in that the sealing element (12) is a skirt (15) which extends from the lower part of said distribution column (23) to the lower annular structure (6).

14. 14. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that the lower part of the lower membrane portion (10) and the sealing element (12) are oriented so as to form downward inclined ramps (29, 30) which converge towards each other, thus creating an effluent collection zone (31).

15. 15. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that the sealing element (12) is removable or capable of being opened.

16. 16. Aquaculture farming device (1) according to any one of the preceding claims, characterized in that it comprises another sealing element (12) which closes the device (1) in its upper part (16).