GB2591167A

GB2591167A - Collector raft and method of accessing a raft

Info

Publication number: GB2591167A
Application number: GB2016834.0A
Authority: GB
Inventors: Enoksen Guttorm
Original assignee: Lift Up As; Mowi ASA
Current assignee: Lift Up As; Mowi ASA
Priority date: 2019-10-25
Filing date: 2020-10-23
Publication date: 2021-07-21
Anticipated expiration: 2040-10-23
Also published as: NO345548B1; GB2591167B; GB202016834D0; NO20191278A1

Abstract

A raft (15, Fig 1) suitable for use in an aquaculture sea cage plant comprising several fish cages comprises a housing 20 enclosing a waterproof chamber (23, Fig 4); the housing including a number of inlets and outlets (21,22, Fig 4) into the chamber for cables and wires (e.g. for removal of bottom waste from the cages) a watertight entrance 28 to the chamber and a connection box (for connecting, splitting or joining the cables) arranged in the chamber. The raft may also include a number of members 17/18 (e.g. ribs or recesses) to which the pipes/cables may be attached. An operator may access the connection box (e.g. for connecting/disconnecting or replacing cables) via the watertight entrance.

Description

Collector Raft and Method of Accessing a Raft

The field of the invention

The present invention concerns a raft for an aquaculture sea cage plant comprising several fish cages, and a method for accessing the raft.

Prior art

A fish farming plant generally comprises a number of fish cages and a common facility for storage of equipment for the plant. A common facility may be on shore, but the plant is often so far from shore that a barge is used. Such a facility or barge is referred to as a main barge or feed barge, and comprises often equipment for controlling the whole plant, not just the feeding. A number of pipes and cables, for instance for feeding, electrical power to lights, cameras and other equipment being arranged at each fish cage, are running from the main barge to each cage.

When the plant is running and there is fish in the fish cages, some dead fish will naturally fall to the bottom of each fish cage, together with remains of feed, faeces and other waste. This kind of waste falling to the bottom of the fish cages, including dead fish, will in the following be referred to as bottom waste. Several systems are developed in order to remove bottom waste in a secure way, for instance from LiftUP Akva AS. From NO 332592 and GB2507077 it is known a system wherein pipes for removing bottom waste from the individual net cages, are connected to a common pipe transporting bottom waste to a common barge, and from GB2557711 it is known rafts for organizing the pipes from the cages to the common barge.

Corresponding systems may preferably also be used with the present invention.

The fish cages of a plant are normally spread out, and cables, hoses and pipes are often floating in the sea between the fish cages, and between main barge and the 30 fish cages. Some of these cables may be fastened to the known rafts mentioned above to avoid tensions and to collect the cables, hoses and pipes in passages in order to make any transportation by boat between the fish cages easier. By gathering the cables, hoses and pipes in passages the risks for damaging the cables by a vessel or boat are also reduced.

However, whenever a plant is rearranged or extended, or when a fish cage should have some equipment replaced or installed, any new cables or pipes must be laid from the main barge to the fish cage, and connected to each raft in between. The same operation must be performed if a cable or pipe should be replaced due to maintenance or damage. Even if a small area of one pipe or cable is damaged for instance due to wear or contact with a boat, the whole cable must be replaced. This is both time consuming and costly, and in addition the replacement operation itself is risky to the personnel performing the operation. Since a boat must be used to perform the laying of a new cable or pipe, there is also a risk to harm other equipment or pipes/cables already arranged in sea.

By "pipe" or "tube" it is in the context of this application meant both stiff pipes of plastic and steel, flexible pipes and tubes, pipes and tubes which may be coiled, and pipes being so flexible that they collapse when no fluid is flowing through them. Correspondingly, by "cables" or "wires" it is meant both stiff and flexible cables and wires, preferably made of plastic, rubber, glass or glass fibre, and electrically conducting materials such as copper. Cables and wires transport electricity, electrical signals, fibre optical signals and the similar, are not meant to transport liquid or gas.

Object of the Present Invention A main object of embodiments of the present invention is to solve the above said problems, and to make it easier to replace, rearrange, reduce and/or increase the number of cables and pipes running to each fish cage. Another object is that this should be performed without limiting the access to the net cages or the farming plant as such. Yet another object is that the pipes, pipe system and other cables should not be exposed to stress and other unnecessary loads. Finally it is an object that it should be possible to install the invention on existing net cages and farming plants.

The invention The objects are fulfilled with a raft according to the appended independent claims. Further advantageous features are given in the corresponding dependent claims.

A raft according to the invention is characterized in that the raft includes a watertight housing enclosing a chamber. The housing comprises a number of inlets and outlets for cables and wires to the chamber, a watertight entrance for providing an operator access to the chamber and a connection box arranged in the chamber. The raft further preferably comprises members for attaching pipes and/or cables.

A "raft" as used in this context, is considerably smaller in size than a regular feed or main barge, as it may also be referred to as a floating connection site. Preferably it is used several rafts according to the present invention at one farming plant, and more preferred one raft is used for every second net cage.

A "connection box" as used in this context, is a box for connecting, splitting and joining signals in cables, such as electricity, fibre optical signals, or the like. One cable may enter the chamber through the inlet, be split in the connection box, and be led out of the chamber through two different outlets. Connection boxes are well known to a skilled person, and thus not described any further in this application. The connection box should be arranged in the chamber in a convenient way to perform its purpose; the cables coming in through the inlet and leaving through the outlet, should be easily connected to the connection box, and the connection box should be easily accessed through the entrance.

By a "watertight housing enclosing a chamber" it is meant that the housing defining and enclosing the chamber is made of watertight material to prevent water from flowing into the chamber. In a preferred embodiment, the inlets and outlets also are designed to prevent water from flowing into the chamber. A connection box is arranged in the chamber, and by having a watertight housing enclosing the chamber, the connection box will be in a dry environment. In a preferred embodiment, the housing is made of a shock-absorbing or hard material, and thus the connection box will be in a dry and protected environment.

The housing further comprises a watertight entrance for providing an operator access to the chamber, and thereby access to the connection box. When an operator needs access to the chamber and the connection box, it is normally only with his hands and arms, and thus the entrance should have a suitable size. However, the entrance may also be smaller and only give access to tools, or larger and give access to the whole body of the operator, depending on the expected use of the raft. To keep the entrance watertight, a lid is preferably covering the entrance when an operator does not need access to the connection box. The lid should be releasable and watertight in closed condition. In a preferred embodiment, the housing has at least two lids arranged in series, meaning that one lid is facing the environment of the raft, and the second lid is facing the chamber. The lids may be arranged in a distance from each other.

The housing defining and enclosing the chamber is arranged in such a way that the outermost lid is above the surface of the sea when the raft is installed in an aquaculture plant, in a preferred embodiment at least parts or more preferred the whole housing is arranged to be above the surface of the sea when the raft is installed in an aquaculture plant. Further, the lid(s) will be open during the operation, and thus the distance from the surface of the sea to the entrance should be sufficient to prevent any splashing of water into the chamber. This distance will depend on the localization of the raft, which is obvious to a skilled person. The lid is typically 1 meter above the sea-level when the raft is installed in a plant.

The housing comprises inlets and outlets for cables and wires to the chamber. The cross section of the inlet/outlet should be large enough to accommodate cables and wires normally used on an aquaculture sea cage plant, yet considerably smaller than the entrance described above. In order to keep the chamber watertight, the inlets and outlets should also be designed to prevent water from flowing into the chamber. This may for instance be provided by installing a lid, check valve and/or membrane into the inlets and outlets, sealing the openings if no cables or wires are running through, or sealing any open cross section of the inlet/outlet if the cables or wires running through are not filling the whole cross section.

In an alternative embodiment, the inlets and outlets are provided sufficiently high above the surface of the sea when the raft is installed in an aquaculture plant, and thereby water will not flow into the chamber. "Sufficient high" depends among others on the weather, wave and water current at the localization in question, which will be obvious to a skilled person.

Each raft is designed to float in the sea and to have sufficient buoyancy, either due to the material it is made of, or by having separate floating elements included or attached to the raft. The raft may for instance be manufactured of a material having a net weight less than water. The raft should carry its own weight and any possible equipment fastened thereon, and also a number of pipes and cables which may be attached to the raft. Some of the pipes may be made of a material floating in the water, and then the carrying capacity of the raft may be reduced correspondingly. The number of pipes, cables and wires to be attached to the raft, will vary from plant to plant, and even depend on the position of the raft in the plant. The carrying capacity of the raft should further be calculated in such a way that it may carry extra load, for instance persons and tools to perform maintenance and/or repairs. The load and buoyancy of the raft must thus be adjusted according to the localization of the raft, which will be obvious to a skilled person.

A preferred material of the raft is plastic having buoyancy in water, preferably having a density of 0,9.

There are usually many cables and wires running to and from a fish cage, for instance for delivery of electricity to various systems such as pumps, feed units and control systems, for delivery of internet or Wi-Fi etc. Some or all of these cables may be inserted into pipes running from the main barge to one or more inlets of a housing on a raft according to the invention. The cables may be connected to the connection box in the chamber and split into a suitable number. Cables running from the connection box to the same fish cage are inserted into a common pipe. the common pipe is connected to one outlet of the chamber in one end, and the fish cage in the other. In this way the number of cables laying in the water between the main barge and the fish cages are reduced to one or more pipes running from the main barge to the raft, and from the raft to each fish cage. The pipes are organized in passages and thus less likely to be hit by a vessel or other equipment being used on the fish plant.

When the fish plant comprises a number of fish cages, preferably more than two, it is an advantage to use more than one raft according to the present invention, preferably one raft every second fish cage. The rafts may be arranged between the fish cages, and/or between a main barge and the fish cages. Then a pipe is arranged between the outlet of one raft and the inlet of the adjacent raft, and thereby the cables are running through pipes and providing signals from the main barge through connection boxes on every raft and to the most distant fish cage. In this way, all cables and pipes will be collected in passages between the rafts and not scattered around in the plant. Further the length of each cable is substantially reduced, which will reduce the wear and tear on the cable, and the costs upon replacement. If any errors or defects occur on the cables, it is also easier to locate the error, depending on the localization of the fish cages not receiving signals, and the rafts between.

With a raft according to the present invention, whenever an extra cable should be led to a fish cage, an operator only needs to access the closest raft and the connection box in the chamber through the entrance of the housing, and insert an extra cable into the pipe running from the chamber to the fish cage in question, and then connect the cable to the cable running to the main barge, via the connection box in the chamber. The same applies if a cable should be replaced. If an entirely new cable should be installed on the plant, the new cable must be installed from the main barge to the first raft first. In this way, if a cable needs to be replaced, only the part between the barge and the raft, between rafts or between the raft and the fish cage needs to be replaced. This is a substantial advantage to the known system, wherein the whole cable must be replaced.

The inlets and outlets are preferably sealed when not in use, and connected to a pipe when in use. When an unused inlet should be used, the sealing is removed, and a pipe is connected. The connection is preferably watertight, and since the pipe is watertight no water will flow into the chamber.

In an alternative embodiment short pipes are attached to the inlets and/or outlets, and when the inlet should be used, a pipe running to the next raft/main barge/fish cage is attached to the short pipe. In this case, the shod pipes will be sealed at their outer end. These short pipes are also referred to as inlet pipes and outlet pipes.

In a preferred embodiment of the invention, the area of the raft is larger than the area of the housing, and the housing is arranged centrally on the raft, protruding vertically.

The outlets and inlets of the housing are preferably facing opposite sides of the raft, and the raft is provided with substantially vertically protruding members, possibly brackets, to hold pipes connected to the outlets and inlets in a given position. The members are preferably arranged at the edge of the raft. In this way any leakage into the chamber, stress and wear on the outlets and inlets and pipes connected thereto, is avoided.

The raft preferably also comprises members for instance brackets, to attach more pipes, cables etc running from the main barge to one or more fish cages, than the cables let into the chamber, such as pipes for fodder, water and air, and/or removal of bottom waste. In this way most of the pipes and cables laying in the water in a fish plant is arranged in passages and attached to the rafts, and the risk for damage by passing vessels or the similar are substantially reduced. As the pipes, cables etc. are attached to the raft, they can move with the raft, and thus with the fish cage, and this is especially important during bad weather conditions with wind and waves, since this leads to a lot of wear and tear on all movable parts, including said pipes, hoses and cables. When they are laying loose in the water they are pulled on fairly independently of each other in different directions, and the different movable parts may be pushed against each other, and wear on each other. By gathering these parts and attach them to a small raft, they are protected from such wear and tear.

In a preferred embodiment, the members for attaching more pipes and cables are also arranged on one edge of the raft, more preferred two opposite edges. The members are preferably protruding vertically upwards, in such a way that the pipes and cables enter the raft through the member on one side, then passes over the raft, and then through the member on the opposite side, before it enters the water again.

In a preferred embodiment the members are ribs, protruding vertically at the edge of the raft, wherein the pipes and/or cables are arranged in recesses between the ribs.

The members to attach more pipes and cables may be the same or integrated with the members holding the pipes connected to the inlets and/or outlets.

In a more preferred embodiment, if the fish plant comprises a system for removal of bottom waste, the raft comprises separate members for fastening the common pipe of the system. These members are preferably arranged centrally under the raft, and thus the common pipe is not lifted out of the water, and does not enter the upper side of the raft. In a more preferred embodiment, the common pipe is integrated in a frame of the raft.

The raft may further comprise means for mooring or anchoring the raft to hold it in position even during wind and current at the locality. The raft may preferably be moored in the mooring of the farming plant, and thus more mooring lines may be avoided. Each fish cage is preferably moored in a frame, and the frames constitute a framework. When the farming plant has a frame mooring, the raft is preferably moored in the frame, and more preferred in a joint of the frame between two rows of net cages. The means for mooring may be any convenient means, but must be sufficiently safe and strong to hold the raft in place even during extreme weather, which is obvious to a skilled person. In one embodiment, the means are lines or ropes being attached to parts or the whole raft and to the mooring point.

The expressions upward, vertically, downward, horizontally etc should be related to the raft when installed in water.

According to one aspect of the present invention, there is provided a raft for an aquaculture sea cage plant comprising several fish cages, characterized in that the raft includes a housing enclosing a waterproof chamber, the housing comprises a number of inlets and outlets for cables and wires to the chamber, a watertight entrance for providing an operator access to the chamber and a connection box arranged in the chamber.

In an embodiment, the raft is characterized in that the housing is arranged above surface of water.

In an embodiment, the raft is characterized in that the raft comprises members for attaching pipes and/or cables.

In an embodiment, the raft is characterized in that the members for attaching pipes and/or cables are protruding upwards from the raft.

In an embodiment, the raft is characterized in that the members are ribs and recesses, wherein the pipes and/or cables are arranged in the recesses between the ribs.

In an embodiment, the raft is characterized in that pipes are connected to the inlet and/or outlet of the housing.

In an embodiment, the raft is characterized in that a plate is protruding upwards from the raft, and that the pipes connected to the inlet and/or outlet are fastened to the 30 plate.

In an embodiment, the raft is characterized in that the raft contains members for holding pipes for removal of bottom waste, preferably below the surface of the sea.

In an embodiment, the raft is characterized in that the housing has at least one releasable lid, covering an entrance to the chamber.

Description of Figures

Preferred embodiments of the invention will in the following be described in more detail with reference to the following figures, in which: Figure 1 shows a fish farming plant using rafts according to an embodiment of the present invention, Figure 2 shows details of a raft shown in circle A in figure 1, Figure 3 shows an alternative to the raft of Figure 2, without any pipes, and Figure 4 shows a vertical cross section taken along line B-B of Figure 3.

Description of a preferred embodiment of the invention.

The following description of an exemplary embodiment refers to the drawings, and the following detailed description is not meant or intended to limit the invention.

Instead, the scope of the invention is defined by the appended claims.

Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

Figure 1 shows fish farming plant, comprising eight net cages 10, one main barge 12, and four rafts 15 according to the present invention. The net cages in the fish farming plant are arranged in two rows, and the rafts 15 are arranged in the centre between the rows, one raft 15 for every second net cage 10. The net cages are moored with frame mooring, and the rafts are moored in the frame mooring. The mooring is not shown, but the buoys 16 being fastened to the frame mooring are shown in Figure 1.

A pipe passage 13 is indicated between a rim of each fish cage and the raft 15 according to the present invention. Another pipe passage 11 is indicated between the rafts, and a third passage 14 is indicated between the main barge 14 and the first raft 15. Each pipe passage 11, 13, 14 may comprise a number of pipes, such as pipes for removal of bottom waste, feeding pipes, cables for electricity, signals and the like, and pipes comprising such cables.

With rafts arranged in a farming plant as shown in Figure 1, it is easy to access the fish cages, from the left side for the fish cages in the left row, and from the right for 15 the fish cages in the right row, and one may access the circumference of nearly the whole fish cage.

A cable running from the main barge to the outermost fish cage in Fig. 1, will when using rafts according to the present invention, be spilt in parts running from the main barge 12 to the first raft 15, between the rafts 15, and one part running from the outermost raft to the outermost fish cage, in total 5 parts.

Figure 2 shows the details of a raft according to the present invention. The raft 15 comprises a square frame 19 and members 17, 18 for attaching pipes and/or cables.

The members are shown as a plate 17 arranged at two opposing edges of the raft, each plate is having a number of ribs 17a protruding above the frame of the raft, with recesses 17b between. The members are also shown as brackets 18 to fasten pipes and cables below the frame 19. The frame is preferably rectangular, and the plates are preferably mounted on the shorter sides, while the brackets are arranged at any place suitable to fasten pipes and cables running under the frame of the raft.

The raft further comprises a housing 20 with a chamber 23, the housing is shown as a vertically protruding cylinder, arranged to be above the surface of the water when the raft is installed. The chamber further comprises a connection box (not shown).

In the shown embodiment of Fig. 2, the housing has eight inlets 21 and outlets 22 for cables to the chamber, and short pipes 24A and 24B (also referred to as inlet and outlet pipes, respectively) are mounted to the inlets and outlets respectively, and led in recesses 17b between the ribs 17a. The inlets and outlets are identical, only the orientation of the raft in the plant will decide which side is outlet and which side is inlet, whereby the side closest to the main barge is inlet. The pipes 24A and 24B are sealed at the outer ends, the sealing is removed when the pipe is to be used.

In the shown embodiment, there are more ribs 17a and recesses 17b than inlet and outlet pipes. Other pipes, cables, wires etc running from the fish cages to the main barge may be attached to the raft by arranging them in the recesses 17b between the ribs on one side of the raft, over the raft, in corresponding recesses on the opposite side, and into the water again. In this embodiment, the members for holding the pipes running into the inlets and/or outlets, and the members for holding other pipes etc are thus integrated in one plate.

The raft shown in Fig 2 also comprises pipes attached to brackets 18. The plant shown in Fig. 1 has a system for removal of bottom waste from the fish cages, and pipes 25 and 26 are branch pipes coming from fish cage 10A and 10B respectively, while pipe 27 are the common waste pipe running to the main barge. In this shown embodiment, the inlets are thus marked to the right side of Fig 2, and the outlet is marked to the left. The branch pipes and common pipe is well known to a skilled person per se, and thus not described any further here.

The housing has a lid 28 at the top, shown as a hat in Fig 2, wherein both the housing 20 and the lid 28 has an outwardly flange 29, 30, and the lid is mounted to the housing by fastening the flanges to each other. This will create a watertight connection, but a sealing between the parts may also be used additionally.

In Fig. 3 and 4 it is shown an alternative embodiment of the raft. For clarity the raft is shown without members for attaching cables and pipes, and without pipes attached to the inlets and outlets. The raft is symmetrical crosswise and lengthwise, and for clarity we have marked the inlets to the right and outlets to the left corresponding to the raft shown in Fig 2. In this embodiment, the common pipe 27 for removal of bottom waste is integrated in the frame 19, and the housing also encloses the common pipe. In this embodiment, the housing has a second chamber 31 comprising the common pipe, and the chamber 23 comprising the connection plate, is arranged above chamber 31 comprising the common pipe 27.

When a raft according to Fig. 2 is installed in a plant, it may not be necessary to use all the pipes 24A, 24B. If the raft is arranged as shown in Fig. 1, possibly only one of the pipes 24A connected to the inlet 21 (also referred to as inlet pipes), and three of the pipes 24B connected to the outlet (also referred to as outlet pipes), are necessary. Cables running from the main barge are inserted in a pipe running in passage 14 and attached to one of the inlet pipes 24A. The desired cables inside the pipe are split in the connection box in the chamber, and led to fish cage 10 A and 10 B through pipes connected to outlet pipes 24B, and running in passaged 13 to the fish cages. The cable is also led to the inlet of the next raft through a pipe connected to a third outlet pipe 24B, and running in passage 11.

When further equipment needing a cable should be installed, an operator inserts more cables in pipes already running in passages 11, 13 and 14, and connects them in the connection boxes. If necessary more pipes may be installed in the different 25 passages and connected to the inlets and outlets to the chamber.

Whenever an operator needs access to the connection box, he/she enters the raft and opens the lid covering the entrance to the chamber. When a cable should be replaced, he/she uninstall the cable in questions from the connection box and the fish cage/adjacent raft/main barge, and removes it from the pipe running between. Then a new cable is inserted in the pipe, and fasted to the connection boxes. In this way only the broken part of the cable is replaced.

Compared to the size of the fish cage, the raft will be small. It only needs to be large enough to encompass the pipes, hoses, and cables running to and from the fish cage, and possibly a person during maintenance and cable change. The raft will therefore usually have a surface area of less than 100 m2, more preferred less than 10 m2, and most preferred 3-6 m2.

In accordance with a preferred embodiment of the present invention the raft is made of HDPE. The frame of the raft is made of pipes, and may be partly or fully be filled with water, EPS or foam, such as EPS foam, depending on the desired buoyancy. The housing may also be made of a HDPE pipe, arranged vertically on the raft. Even the ribs, the brackets and the pipes connected to the inlets and outlets to the chamber may be made of HDPE.

Claims

Claims 1. Raft for an aquaculture sea cage plant comprising several fish cages, wherein the raft includes a housing enclosing a waterproof chamber, the housing comprises a number of inlets and outlets for cables and wires to the chamber, a watertight entrance for providing an operator access to the chamber and a connection box arranged in the chamber.
2. Raft according to claim 1, wherein the housing is arranged above surface of water.
3. Raft according to any of the preceding claim, wherein the raft comprises members for attaching pipes and/or cables.
4. Raft according to claim 3, wherein the members for attaching pipes and/or cables are protruding upwards from the raft
5. Raft according to claim 3 or 4, wherein the members are ribs and recesses, wherein the pipes and/or cables are arranged in the recesses between the ribs.
6. Raft according to any one of the preceding claims, wherein pipes are connected to the inlet and/or outlet of the housing.
7. Raft according to claim 6, wherein a plate is protruding upwards from the raft, and the pipes connected to the inlet and/or outlet are fastened to the plate.
8. Raft according to any one of the preceding claims, wherein the raft contains members for holding pipes for removal of bottom waste, preferably below the surface of the sea.
9. Raft according to any one of the preceding claims, wherein the housing has at least one releasable lid, covering an entrance to the chamber.
10. A method for providing access to an aquaculture sea cage plant comprising several fish cages, the method comprising: providing a raft including a housing enclosing a waterproof chamber; wherein the housing comprises a number of inlets and outlets for cables and 5 wires to the chamber, and a watertight entrance; and, wherein the watertight entrance provides an operator access to the chamber and a connection box arranged in the chamber.