Fish farm with a closed submersible unit

Abstract

The invention relates to a fish farm for fish farming including a closed unit (1) attached to a floating collar (5) through an immersion adjustment system (28) for locating the closed unit (1) below t

Description

Technical field The present invention relates to a fish farm with a closed submersible fish pen i.e., a fish farm for fish, in particular salmon, including a submersible closed unit, which is attached to a floating collar through an immersion adjustment system for positioning the closed unit below the water surface and in the water column. The invention also relates to supply and discharge of water to / from the closed unit. Object of the invention One of the aquaculture industry's goals is for the sea to be used in a way that promotes environmentally sustainable development. The industry therefore seeks to develop solutions that are energy efficient, reduce consumption of fossil fuels and reduce a climate footprint. Today, the industry's biggest problems include diseases and parasites and in particular the spread of salmon lice. Escaping fish is also a major problem especially for the wild salmon stock - and is often due to technical failure, incorrect use of equipment or vessels, or storms. In addition, discharge of waste from the aquaculture industry has increased, and the industry accounts for large amounts of pollution in the coastal areas. The waste largely includes of waste from feed and excrements / faeces from the fish, but also waste from medicaments in used during for example, delousing. The environmental impact as a concentration of pollution from fish farms will be greatest just below or in the immediate vicinity of the fish farms, and the discharges could potentially affect life on the seabed and change the environmental conditions near the sites. The abovementioned problems suggest that the industry needs closed facilities to prevent and reduce the environmental impact, and to ensure growth and sustainability in the future. New locations in more weather-exposed areas at sea are considered to increase production. Both closed and semi-closed fish farms where the purpose is to remedy the noted problems are already in use. Land-based plants are also used, but such plants have so far proved problematic as the plants require considerable land use, increased energy consumption, water consumption, sludge production and significant investments. The technical and biological risk of land-based production is also significant. Several of today's semi-closed facilities for use at sea are not completely closed, because the closed unit is not completely sealed. Examples include solutions shown NO 344466 and NO 334524. None of these solutions are completely closed or can be adjusted deep in the water column. They include a physical barrier (wall or cloth I net) that confines the fish from the surroundings. The environment from which the fish is sought to be delimited is mainly the upper water masses to avoid lice and other pathogens, while the waste substances are released as in traditional farmed nets. The disadvantages of these structures include that they are cumbersome to operate, they do not sufficiently limit pollution from the facilities, and there is a great risk of breakdown due to the material of the net bags. Patent NO 344466 relates to a combination of a lice skirt and dense steel wall as a barrier between fish and the environment in the upper water masses. This is a newly developed steel structure and is not based on current conventional farming solutions. The invention can withstand a significant wave height (Hs) of 2.4 meters compared to today's traditional 160-meter plastic rings that can withstand 4-6 meters (Hs). There is no collection of sludge and is thus an unsuitable structure for farming in fjords with reduced water exchange. Patent NO334524 disclose a more traditional design. A physical barrier located between the fish and surrounding water masses is either a waterproof or a plankton-repellent material. This type of semi-enclosed cage is not very suitable for locations exposed to high currents and bad weather and will only provide partial protection against the surrounding water masses. In the case of a turbulent flow image, the water masses on the outside and inside of the cage will mix. This structure uses several elements from current farming equipment but has no solution to the sludge problem or solve utilization of aquaculture in weather-exposed areas. Background art NO 332341 disclose a cage structure for fish farming with a closed cage attached to a floating collar, which is partially submerged. The invention includes an inlet line for supply of fresh water supplied through one or more water spreaders and has an outlet in the lower part of a bottom part of the cage, supplying water and waste via a drain line. NO 344177 also describes a closed cage for storing fish on their way to be to be slaughtered, where the cage can be lifted or lowered. The cage comprises one or more buoyancy chambers extending vertically in the cage, for filling and evacuating a buoyancy medium in the form of water. NO 342403 discloses a sealed cage arrangement which has a closed cage bag with impermeable walls. The design has two or more floating collars to limit the forces imposed by the environment on the closed cage bag. One or more inlet pipelines supply fresh water and at least one outlet pipe for water and waste. A method for treating the water to be supplied to the breeding cage is also described. NO 175341 relates to a device and a method for supplying water to a closed cage. Water is pumped from a depth that is deeper than the cage itself, and to a water spreader located at the inlet. The water is then distributed mainly tangentially into the cage to ensure circulation of the water inside the cage. NO 178811 relates to a fish cage with a device for removing feed residues and dead fish from the bottom part of the cage. The invention applied for is based on today's well-functioning farming equipment where it is the new closed submersible production unit with associated functioning components which is an innovation and the invention itself. NO 332341 and NO342403 fails to disclose a completely closed submersible production unit where the unit is attached to an adjustment system which is attached to a floating collar, and where the device can be lowered below sea level. NO 332341 and NO342403 also fails to disclose a production unit with pressure valves in the walls of the unit, for volume adjustment and water intake in the centre for optimal water circulation. It is particularly pointed out that today's solutions only solve some of the known challenges facing the industry today. The production unit of the present invention will have a complete physical barrier against surrounding water masses in the form of a cloth or alternatively other flexible sealing materials. A completely closed production unit provides a controlled environment to ensure fish health and the ability to lower the unit below a water surface during periods of storms and provides the ability to use more exposed locations at sea. In patent NO 178811 only one collection system and one transport hose are used to transport sludge and dead fish. Eide's invention differs significantly from this in that there are two separate collectors and two separate transport hoses to the surface. Another difference is also that several of the known inventions depend on geodetic water level inside the bag to ensure good expansion of the closed bags to which the inventions relate. There is thus a need for a higher water level on the inside of the fabric than on the outside. This extra water level causes extra weight in the structure of the system so that the floating collar is dependent on extra buoyancy. The invention applied for will not need such a structure because overpressure will be created inside the unit. Furthermore, the water intake in several of the known art solutions is located on the side of the cage and must be pumped up to the surface either through or over the physical barrier between fish and the environment. The water supply unit is in several of the known systems mounted at the water surface or on a floating collar. The result is that the required pump is locate on the suction side rather than on the pressure side and is therefore relying on a rigid water intake (pipe), as a flexible intake (e.g. canvas) will collapse when the pump reduces the pressure in the pipe. Some prior art solutions rely on several pump units to create the desired water current configuration in a closed unit, because the pumps I water distribution ports are located at the side of the cages. Drawbacks with prior art solutions include high energy consumption, several pump units, long pipes etc., and the solutions are considered to be complicated, not particularly cost-effective and very cumbersome structures. The present invention seeks to solve these problems, and the invention therefore claims only one mechanical water supply / water lifting unit, since the water supply unit is located at the centre of the cage. The water is supplied through a flexible water distributor which also extending at the centre of a closed unit. The present invention will reduce the required head when pumping water and thus the required energy consumption. Summary of the invention The present invention relates to a fish farm including a traditional floating collar through an immersion adjustment system for positioning the closed unit in the water column, further including a water supply unit such as a pump unit (preferably mechanical) for water located at the centre of the bottom of the closed unit that supplies new water into the unit. The closed unit further includes pressure valves located in the walls of the unit for volume adjustment. Accordingly, the present invention discloses a fish farm adapted to be located in a body of water. The fish farm includes a floating collar. A closed unit is attached to the floating collar via an immersion adjustment system. The closed unit includes a water supply system including a water supply unit at a bottom of the closed unit. The water supply unit is adapted to supply and distribute water in the closed unit through a flexible water distributor. A waste system is adapted to remove of waste accumulated at the bottom part of the closed unit. A drain hose is adapted to discharge waste from the waste system. A double barrier includes a net and a sealing flexible barrier forming walls of the closed unit. Pressure valves are adapted to control a pressure in the closed unit to a pressure exceeding an ambient water pressure. The net may be attached to at least one of an inside of the sealing flexible barrier and an outside of the sealing flexible barrier. The closed unit may be kept unfolded and stable by a fastening device extending through the closed unit. The water supply unit may be located at the centre of the closed unit. The water supply unit may include a filter adapted to filter the water before it is supplied to the closed unit. The flexible water distributor may include a vertical axis and a perimeter, and nozzles may be distributed along the perimeter and the vertical axis. The nozzles may be angled out from the water distributor to create circulation. The closed unit may include a zipper, and at least a portion of the double barrier of the net and the sealing flexible barrier may be removable for physical access to the fish. A jump fence may be releasable from the closed unit and may be adapted to be hung along the upper part of the floating collar to prevent living organisms from escaping fish farm. A waste system for dead fish may be located at the bottom of the net, while a sludge and waste system may be located at the lower part of the sealing flexible barrier. The fish farm may further include a dead fish hose adapted to transport accumulated dead fish to the surface, and waste hose adapted to transport sludge and waste for further processing. The waste system for collecting dead fish, sludge and other waste may be located in the lower part of the sealing flexible barrier. The fish farm may further include a common waste hose adapted to transport dead fish, sludge and waste to the surface for further processing. The immersion adjustment system may be adapted to lower the closed unit below the sea surface to a desired depth. The immersion adjustment system may be adapted to control the depth of the closed unit between a raised position and a lowered position at a desired depth. Furthermore, the invention relates to a method for supply and discharge of water to / from a fish farm as described above, comprising the steps of injecting water into the closed unit through the water supply unit located at the centre of the closed unit and further into the flexible water distributor and ensuring a pressure inside the closed unit, exceeding an ambient pressure with the pressure valves to ensure water exchange and volume control. The method may further include injecting water through the water supply unit and through the flexible water distributor and distributing water homogeneously throughout the closed unit through nozzles located in the water distributor, where the nozzles are angled to create circulation. The method may further include releasing water and air through the pressure valves to prevent an air pocket from occurring at the upper part of the closed unit. The production unit may have a complete physical barrier against surrounding water masses. Suitable materials include flexible sealing materials such as canvas. The completely closed unit separates fish and surrounding water masses at all times, even when submerged. The water supply unit is located at the centre of the production unit, allowing a single water supply unit will be sufficient. The mechanical water supply unit may alternatively be equipped with filtration means to filtrate the water before it is transported into the closed unit. The injected water will be homogeneously distributed throughout the closed unit by a flexible water distributor with nozzles, for example by using a fabric tunnel, which will be able to provide circulating flow inside the unit. This gives the closed production unit a circulating flow from the centre and outwards, up and down the unit, which provides a supply of fresh water throughout the unit and welfare for the fish. This is enabled by the water supply unit and the water distribution from the centre. The water distributor will be a flexible sealed structure of cloth or tarpaulin, which can be folded. Oxygen can be added by, for example, mounting diffuser equipment on the flexible water distributor for additional supply in the closed production unit. The production unit is equipped with pressure valves in the walls of the unit, which will release the supplied water so that the bag at all times maintains the best possible shape by the overpressure. The pressure valves ensure good water circulation and control the pressure inside the closed production unit, so that there is no danger of overfilling which could cause the bag to burst. Several pressure relief valves are installed in the top of the closed unit. A safety device with valves for compressed air inside the closed unit (eg Lift-up dead fish system), will ensure that if an air leak occurs, the valve will prevent a build-up of an air pocket in the closed unit which provides extra buoyancy so that the closed unit can lift. The safety device and the valves are designed such that that sludge, waste and dead fish do not escape, but are collected in the bottom part of the closed unit, so that it can be transported to the surface through a hose. This ensures favourable environmental conditions for the fish. Attaching the closed unit to an existing plant structure (floating ring with bottom ring) or another type of cage with alternative weights, it will be possible to lower the closed unit below the sea surface. This will be done by means of, for example, a winch, or any equipment for adjusting the closed production unit below the water surface and in the water column. The invention reduces the risk of escaping fish and the risk of getting in conflict with floating elements, storms and waves present at the water surface. The closed production unit in the submerged state will have less load and wear on the structure and have an extended service life in contrast to other closed concepts which must withstand forces from waves, current and movements present at the sea surface. The closed unit will also have a keeper net I seine, to provide a double barrier against escape. There will be a distance between the inner net and the outer sealing flexible structure (in the form of canvas or other sealing flexible barrier) in the bottom part of the cage. This allows sludge and other waste to fall through the net and down into the bottom part of the outer sealing flexible structure where it is transported to the surface for further processing. Dead fish are collected at the bottom of the net and are transported to the surface through a hose, separate from the sludge. Alternatively, the sealing flexible structure can also be located on the inside of the net. In this embodiment, dead fish, sludge and other waste will be collected at the bottom of the flexible material, and then collectively transported to the surface for processing. Brief description of drawings Figure 1 is a schematic representation of a submersible closed unit, where a double barrier includes nets attached to the inside of a sealing flexible barrier, including the structure installed in an adjustment system; Figure 2 shows an embodiment of the water intake and waste management elements; Figure 3 shows a design of the valves; Figure 4 shows a design of the submersible closed unit installed in an adjustment system; Figure 5 is a schematic representation of a flexible water distributor; Figure 6 is a schematic representation of the submersible closed unit according an embodiment of the invention, seen from above; Figure 7 shows an embodiment of a submersible closed unit in its entirety, where the double barrier includes of a flexible sealing material attached to the inside of a net, with indicated figures on the individual parts included in the structure installed in an adjustment system; and Figure 8 shows the closed unit in three stages, including the surfaced state in the first drawing, the closed unit immersed to 10 meters in the second drawing and the closed unit immersed to 35 meters in the last drawing. Detailed description of the invention Figure 1 shows a traditional submersible farming aquaculture cage, with a submersible closed unit 1 for use in the aquaculture industry. Fresh or seawater will enclose the cage and the walls of the closed unit will form a physical barrier I barrier to the aquatic environment outside the closed unit 1. The structure outside the closed unit 1 will be open and water may enter this area. The submersible closed unit 1 will be equipped with a double barrier including of net 11 and a sealing flexible barrier 12 in the form of, for example, fabric / canvas / tarpaulin. As shown in figure 1, this can be done by fastening the net 11 on the inside of the sealing flexible barrier 12, by fastening device 29 which is continuous throughout the unit 1. The fastening device 29 will keep the net 11 stable and unfolded inside the closed unit 1. The closed unit 1 is supplied with water through a water supply unit 2 located in the centre of the closed unit 1. Injected water is then distributed by a flexible water distributor 3 in the closed unit 1. Nozzles 23 around and along the vertical axis of the flexible water distributor 3 distributes the water homogeneously throughout the closed unit 1 and provides a circulating flow. To ensure further circulation in the closed unit 1, the flexible water distributor 3 can be equipped with nozzles 23 which are angled out from the water distributor 3. This will help control the water flow and create circulation of the water masses inside the closed unit 1. The water is transported out through valves 4 to ensure good water exchange and water mass flow control. The valves will be open at elevated pressure 15 and will be closed 16 if the pressure falls below a certain value, as shown in figure 3. The number and location of the valves 4 may vary and will depend on the size of the closed unit 1. The net 11 is located on the inside of the sealing flexible barrier 12 of the closed unit 1. The net 11 provides for extra safety against escaping fish and ensures a gentle handling of the fish during handling, drying and various operations. The collection system for dead fish 14 is located at the bottom of the net 11, while the sludge and waste system 13 is located in the lower part of the sealing flexible barrier 12. Dead fish are transported to the surface by means of dead fish hose 7 and sludge and waste through waste hose 6, for further processing. The water supply unit 2 is designed to prevent it from conflicting with dead fish hose 7 or waste hose 6 and will constantly supply fresh water to the submersible closed unit 1. The submersible closed unit 1 will be attached to an adjustment system 28 for immersion in the water column. Such systems are known from the prior art. Figure 4 disclose an example of a method where the closed unit 1 is part of an adjustment system 28 which is attached to a floating collar 5 with a bottom ring 10 as a weight. The closed unit 1 will be attached to the adjustment system 28 through a fastening loop 9. The closed unit 1 will be kept unfolded by the bottom ring rope / weight rope 17 by a loop 19 and rope 20 arrangement. A raising and lowering unit 22, preferably in the form of, for example, a winch, can adjust the winch rope 8 length and thus raise and lower the closed unit 1, allowing it to be lowered below the sea surface. A stop element 21 is also fitted to prevent wear between the closed unit 1 and the bottom ring 10 if the raising and lowering unit 22 collapses. Sliding rings 18, allow the closed unit to slide along the bottom ring rope 17 so that it maintains its shape below the water surface and in the water column. Figure 6 shows the submersible closed unit 1 seen from above, in the same embodiment as the rest of the structure. Pressure relief valves 4 are installed to release water and air to prevent air pockets to form in the upper part of the closed unit 1. The pressure relief valves 4 are the same as those located in the wall of the closed unit 1 shown in Figures 1 and 3. The number and location of these pressure relief valves 4 may vary according to the size of the unit. The roof of the structure can be removed in connection with the delivery offish for slaughter or other operations that require physical access to the fish. When the submersible closed unit 1 has been lifted to the surface, it must be possible to release a jumping prevention net 24 from the fabric and hang it up along the upper part of the floating collar 5 to prevent fish from jumping out of the cage. Figure 7 shows an alternative embodiment where the double barrier is made by fastening a sealing flexible barrier 31 on the inside of a net 30, with a fastening device 29 which is continuous throughout the closed unit 1. The fastening device 29 will keep the sealing flexible barrier 31 stable and unfolded. Water is supplied as described in relation to Figures 1, 2 and 5. The valves 4 will be attached to the sealing flexible barrier 31 in the same way as in Figures 3 and 6, and the waste management system 32 for collecting dead fish, sludge and other waste will be mounted in the bottom of the sealing flexible barrier 31 after which dead fish, sludge and other waste are transported through a common waste hose 33 out of the unit. Regarding immersion of the closed unit 1, this can also be carried out in the same way as the procedure indicated in Figure 4. As shown in Figure 8, is it possible adjust the depth of the closed unit 1 in the water column. The unit can be raised to a maximum uplifted condition 25, be immersed to a depth of 10 meters 26 and can be lowered further into the water column to the desired depth 27. The adjustment system 28 will determine how far into the water column (how deep) the closed unit 1 can be lowered. The term fish farm is not intended to restrict the invention to “fish” farming. The term “Fish farm” is intended to cover a farm used for rearing any type of marine organisms. The closed unit forms the fish habitat or residence chamber.

Claims

1. A fish farm adapted to be located in a body of water, comprising:-a floating collar (5);-a closed unit (1) attached to the floating collar (5) via an immersion adjustment system (28), the closed unit (1) comprising;-a water supply system including a water supply unit (2) at a bottom of the closed unit (1), adapted to supply and distribute water in the closed unit (1) through a flexible water distributor (3);-a waste system (13, 14, 32) adapted to remove of waste accumulated at the bottom part of the closed unit (1);-a drain hose (6, 7, 33) adapted to discharge waste from the waste system (13, 14, 32);- a double barrier including a net (11, 30) and a sealing flexible barrier (12, 31) forming walls of the closed unit (1); and- pressure valves (4) adapted to control a pressure in the closed unit (1) to a pressure exceeding an ambient water pressure.

2. A fish farm in accordance with claim 1, wherein where the net (11) is attached to at least one of an inside of the sealing flexible barrier (12) and an outside of the sealing flexible barrier (12).

3. A fish farm in accordance with claim 1, wherein the closed unit (1) is kept unfolded and stable by a fastening device (29) extending through the closed unit (1).

4. A fish farm in accordance with claim 1, wherein the water supply unit (2) is located at the centre of the closed unit (1).

5. A fish farm in accordance with claims 1 and 4, wherein the water supply unit (2) includes a filter adapted to filter the water before it is supplied to the closed unit (1).

6. A fish farm in accordance with claims 1, wherein the flexible water distributor (3) includes a vertical axis and a perimeter, and wherein nozzles (23) are distributed along the perimeter and the vertical axis, and where the nozzles (23) are angled out from the water distributor (3) to create circulation.

7. A fish farm in accordance with claim 1, wherein the closed unit includes a zipper, and wherein at least a portion of the double barrier of the net (11, 30) and the sealing flexible barrier (12, 31) is removable for physical access to the fish.

8. A fish farm in accordance with claim 1, wherein a jump fence (24) is releasable from the closed unit (1) and is adapted to be hung along the upper part of the floating collar (5) to prevent living organisms from escaping the fish farm.

9. A fish farm in accordance with claim 1, wherein a waste system for dead fish (14) is located at the bottom of the net (11), while a sludge and waste system (13) is located at the lower part of the sealing flexible barrier (12).

10. A fish farm in accordance with claims 1 and 9, further including:a dead fish hose (7) adapted to transport accumulated dead fish to the surface; anda waste hose (6) adapted to transport sludge and waste for further processing.

11. A fish farm in accordance with claim 1, wherein the waste system (32) for collecting dead fish, sludge, and other waste, is located in the lower part of the sealing flexible barrier (31).

12. A fish farm in accordance with claims 1 and 11, further including a common waste hose (33) adapted to transport dead fish, sludge, and waste to the surface for further processing.

13. A fish farm in accordance with claim 1, wherein the immersion adjustment system (28) is adapted to lower the closed unit below the sea surface to a desired depth.

14. A fish farm in accordance with claims 1 and 13, wherein the immersion adjustment system (28) is adapted to control the depth of the closed unit (1) between a raised position (25) and a lowered a desired depth (27).

15. Method for supply and discharge of water to / from a fish farm according to any of the preceding claims, comprising;injecting water into the closed unit (1) through the water supply unit (2) located at the centre of the closed unit (1) and further into the flexible water distributor (3);ensuring a pressure inside the closed unit (1) exceeding an ambient pressure with the pressure valves (4) to ensure water exchange and volume control.

16. A method according to claim 15, the further including:injecting water through the water supply unit (2) and through the flexible water distributor (3);distributing water homogeneously throughout the closed unit (1) through nozzles (23) located in the water distributor (3), where the nozzles (23) are angled to create circulation.

17. Method according to claims 15 or 16, further including: releasing water and air through the pressure valves (4) to prevent an air pocket from occurring at the upper part of the closed unit (1).

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