AU2014269197A1

AU2014269197A1 - System and fish cage for fish farming

Info

Publication number: AU2014269197A1
Application number: AU2014269197A
Authority: AU
Inventors: Geir FURBERG
Original assignee: AQUALINE AS
Current assignee: AQUALINE AS
Priority date: 2013-05-21
Filing date: 2014-05-19
Publication date: 2015-11-26
Also published as: CL2015003390A1; CA2913123A1; NO334957B1; EP2999331A1; WO2014189383A1; NO20130703A1; EP2999331A4

Abstract

Fish cage comprising floating collar (1), net cage and sinker tube (2), wherein a number of strengthening elements (4, 5) are connected to the fish cage, and wherein the sinker tube (2) is connected to the strengthening elements. The strengthening elements comprise vertical strengthening elements (4, 4A) running downwards from the floating collar to the sinker tube, and horizontal strengthening elements (5) running along the circumference of the net cage. The strengthening elements (4, 5) are connected to each other in cross points (11), and the sinker tube (2) is connected to the strengthening elements (4, 5) in such a way that the strengthening elements (4, 5) carry the weight of the sinker tube (2). The fish cage comprises further a number of lines (7) distributed along the circumference, as the lines run from the floating collar (1) to the sinker tube (2), without carrying the weight of the sinker tube when the sinker tube is in its lower position. System for lifting sinker tube of such a fish cage, which comprises a number of lines (7) distributed along the circumference of the net cage, as the lines runs from the floating collar (1) to the sinker tube (2), and at the least one device (8) for tightening and pulling the lines, as an upper end of each line is connected to the device (8) and a lower part is connected to the sinker tube (2).

Description

WO 2014/189383 PCT/N02014/050079 1 SYSTEM AND FISH CAGE FOR FISH FARMING The present invention is related to a new fish cage, and a new system for lifting the sinker tube, according to the preamble of the independent patent claims. 5 Background There is a problem regarding fish farming that fish escapes from the plant, often due to holes in the wall of the net cage. The holes may arise due to wear and tear, defects or extreme weather. This is a disadvantage because farmed fish is getting 10 mixed with wild fish, but it is also a large economical loss to the fish farming industry. A traditional fish cage for farming salmon and trout comprises among others a floating collar being on the surface of the ocean, a net cage stretching downwards from the floating collar, and a sinker tube holding the net cage dilated at the lower 15 end. The sinker tube is fastened to the net cage in the transition between net wall and net bottom, but the weight of the sinker tube is normally carried of a number of chains running between the sinker tube and the floating collar. The sinker tube chain is running on the outside of the net cage, and when there is strong ocean current or wind, the net cage may be displaced towards the chain in such a way that the chain 20 touches and tears the net cage. Over time, the chain may wear the net, and a hole may arise. By "floating collar" it is in this patent application meant devices at the surface of the sea holding the fish cage floating. This is traditionally two pipes running in circle, 25 wherein the pipes are side by side, and fasten to each other by brackets. On the brackets there are often vertical bars making attachment for a handrail at the upper end. The net cage is fastened to the inner side of the circles, and the floating collar holds the net cage floating. 30 By "net cage" it is in this patent application meant the net holding the fish inside the fish cage. The net cage is performed as a bag having walls and bottom, and has preferably shape as a circular cylinder with conical bottom. The upper part of the net cage is fastened to the floating collar, while the lower part, preferably lower part of the wall or the transition between wall and bottom, is fastened to a sinker tube. The 35 material of the net cage and the net cage in total is chosen according to traditional criteria, with a convenient mesh width.

WO 2014/189383 PCT/N02014/050079 2 By "sinker tube" it is in this patent application meant a device being lowered into the sea, and holding the net cage dilated. The sinker tube has preferably about the same shape and diameter as one of the rings of the floating collar, and it is heavy so that the fish cage is held down and does not float up. The lower part of the net cage is 5 fastened to the sinker tube, and the sinker tube will thus also make sure that the lower part of the net cage is dilated. In different situations, one may need to lift the net cage, and this is performed by lifting the sinker tube. Lifting may for instance be necessary upon emptying or 10 treatment of disease of the fish in the fish cage, but also upon cleaning and replacement of the net cage. The net cage is lifted by pulling the sinker tube chain, and by pulling the net and collecting it at the inside of the fish cage. The sinker tube chains are distributed along the floating collar and must be pulled at the same time, or stage by stage on turn to avoid risks for stretch and tear of the net. The same is 15 related to lifting and collecting of the net cage. This is time consuming and labor intensive, and the work may also be heavy and dangerous. Many different types of fish cages are known, for instance from the patentee, CN 2733895 and NO 329812, and from WO 01/65925, SU 641943 and CN 101878742 20 different systems for lifting/lowering the net cages are known. However, none of these fish cages solve the problems related to the sinker tube and wear and tear of the net related to that. Object 25 There is an object of the present invention to provide a fish cage whereby wear of the net is reduced. Further, it is an object of the present invention to provide a system for lifting the net, as the system should be time- and labor saving, and also less risky. Finally it is an object to provide a fish cage and a system being designed for all kinds of weather and ocean currents. 30 The invention The objects are met by a fish cage and a system according to the characterizing part of the independent patent claims. 35 A fish cage according to the present invention comprises a floating collar, a net cage and a sinker tube, wherein strengthening elements are connected to the net cage, and wherein the sinker tube is connected to the strengthening elements. The WO 2014/189383 PCT/N02014/050079 3 strengthening elements are running vertically downwards from the floating collar towards the sinker tube, and horizontally along the circumference of the net cage. The elements are connected to each other at cross points. 5 A system for lifting the sinker tube of a fish cage according to the present invention, comprises a number of lines running from the floating collar to the sinker tube, and at the least one device for tightening and pulling the lines. The lines are evenly distributed along the circumference of the fish cage, and an upper end of the lines is fastened to the device(s), and a lower end is fastened to the sinker tube. In a 10 preferred embodiment, the device(s) for tightening and pulling the lines, is a winch, and in a more preferred embodiment, it is used one winch per line. A fish cage according to the present invention has strengthening elements at or in the net cage. The strengthening elements are running both downwards from the 15 floating collar to the sinker tube (vertical elements), and around the circumference of the net cage (horizontal elements). The strengthening elements are fastened to each other in cross points, so that a grid of elements is made. These elements will distribute the forces around the whole fish cage in such a way that stretches to the net are better distributed, and the danger for tear is less. 20 The upper ends of the vertical strengthening elements are preferably fastened to the floating collar, while the lower ends are connected to the sinker tube. The fastening between the strengthening elements and the floating collar and the sinker tube, respectively, may be performed in many ways which will be obvious to a person 25 skilled of the art. Thus, the fastening is not described any further here. In a preferred embodiment of the present invention, the horizontal strengthening elements are fastened directly to the net, preferably along the whole circumference of the net. The vertical strengthening elements are preferably also fastened to the 30 net cage along their entire length, except in the upper part. In cases where the strengthening elements are longer than the fish cage, for fastening to the sinker tube, the exception is also valid for the lower part. In alternative embodiments, the strengthening elements are only fastened point by point. 35 An upper part of the vertical strengthening elements are preferably not fastened to the net cage, as the upper end of the elements are fastened to the floating collar at a distance from the inner circumference where the net cage is fastened, in such a way WO 2014/189383 PCT/N02014/050079 4 that the upper part of the elements are forming an inclined angle towards the net cage. In this way the forces are better distributed in the floating collar, and a stretch in the upper part of the net cage is achieved, in such a way that it is kept dilated. 5 In an alternative embodiment is a net fastened to the upper part of the strengthening elements in such a way that a net cage is provided on the outside of the actual net cage of the fish cage. This net will function as a predator net, as predators will not get till the actual net cage. 10 The strengthening elements are preformed to carry the weight of the sinker tube, and are preferably made of fiber rope being sewn to the net cage. The sinker tube is either fastened directly to a lower part of the vertical elements or via other means. The sinker tube maintains stretch of the net, and lower part of the net dilated. The vertical elements will be held tight by the weight of the sinker tube, and since the 15 vertical and horizontal strengthening elements are connected to each other in cross points, the horizontal elements will be pulled outwards, and the fish cage will thus be held dilated over the whole depth of the net, and during most conditions and sea currents. The dilation will ensure good opening of the meshes in all parts of the net cage, which will ensure good through-put of water, and thus sufficient supply of 20 oxygen. In a preferred embodiment of the present invention, the sinker tube is connected to the strengthening elements in such a way that the sinker tube is lying below and outside of the transition between wall and bottom of the net cage. In this way it is 25 achieved a favorable distribution of forces which will prevent the meshes of the net to be drawn askew. When the sinker tube is fastened to or at the strengthening elements, the need for a tight chain or line carrying the weight of the sinker tube is gone, and one avoids that 30 such a line will be touching the net and may cause wear with the danger of a hole in the net. According to the present invention it is performed a system for lifting the sinker tube, wherein the sinker tube is a part of a fish cage according to the present invention, as 35 described above. The system comprises a number of lines running from the floating collar to the sinker tube, as the lines do not carry the weight of the sinker tube, but are lying loose in the water when the sinker tube is at its lower position. Since the WO 2014/189383 PCT/N02014/050079 5 lines are loose they will not harm the net. The upper end of each line is preferably connected to one or more devices for tightening and pulling the lines, for instance a winch. The winch(es) is preferably located on the walkway. In cases where it is used more than one device, the devices should be synchronized in such a way that pulling 5 of the lines, which will result in lifting of the sinker tube, may be done at the same time and at the same speed, in such a way that the tube is lifted evenly around the fish cage and that stretch in the net cage is avoided. By line" it is in this patent application meant any convenient rope, chain, wire, strap 10 or the similar. When the sinker tube is at its lower position, the weight of the sinker tube is carried of the strengthening elements of the fish cage, and the lines are loose. When the sinker tube is lifted or in a lifted position, the lines are carrying the weight of the sinker tube. The lines must thus be performed in such a way that they both can carry the weight of the sinker tube, and run loose at the outside of the net 15 without harming the net. This will be obvious to a person skilled of the art. The winch or device to pull the lines comprises a reel wherein the line is coiled and stored when it is pulled out of the water. In a preferred embodiment of the present invention, the line is led through an aperture in the walkway and onto the reel. The 20 aperture is preferably parallel with the length of the reel, and has preferably the same length as the reel. Further, the aperture must be sufficiently large so that the line may travel naturally along the reel and coil evenly on the reel. Further, the line may be fouled after being in the sea for a period. To scrape this off 25 the line, the line is preferably led through a convenient device before the line is coiled on the reel. The invention will in the following be described with an example given to illustrate the invention, and should not be used to interpret the invention, as it is defined in the 30 enclosed claims, restrictive. Example A preferred embodiment of the invention will in the following, be described with reference to the enclosed Figures, where 35 Figure 1 shows a fish cage and a system according to the present invention, seen in perspective, Figure 2 shows an enlarged section of a part of the fish cage in Figure 1, and WO 2014/189383 PCT/N02014/050079 6 Figure 3 shows an enlarged section of a part of the floating collar of the fish cage shown in Figures 1 and 2. The fish cage shown in Figures 1, 2 and 3 is in accordance to the present invention, 5 and comprises a floating collar 1, a sinker tube 2 and a net cage 3. A number of strengthening elements are fastened to net cage, vertical strengthening elements 4 and horizontal elements 5, running along the actual net cage. In the shown embodiment, the fish cage is provided with 4 horizontal strengthening element; one at the transition between net wall and net bottom in the net cage, one at the 10 fastening to the floating collar, and two intervening elements. The embodiment is further shown with vertical strengthening elements at every third bracket of the floating collar. This may, of course, vary. The strengthening elements 4, 5 are sewn to the net cage, and to each other in cross points 11, in such a way that a grid of strengthening elements are made. The net is not shown in the Figures. 15 In the shown embodiment, the vertical strengthening elements 4 run along the net wall and in the transition between net wall and net bottom, the sinker tube 2 is fastened to cross point 11 between vertical and horizontal strengthening elements via connection means 6. The sinker tube is fastened in such a way that it is below 20 the wall of the fish cage, and has a size corresponding to the floating collar so that the lower part of the fish cage is held dilated. In the shown embodiment, an upper part 4A of each vertical strengthening element 4, from the second uppermost horizontal strengthening element 5, is not connected 25 to the fish cage, but stretches in an angle from this towards the floating collar, preferably towards centre of the floating collar. In this way a better distribution of the forces affecting the floating collar, is achieved, and the horizontal strengthening element wherefrom the vertical elements are no longer fastened to the net cage, will be stretched outwards in such a way that the fish cage is held dilated. 30 Between the floating collar 1 and the sinker tube 2, there are a number of lines 7 for lifting the sinker tube, in the shown embodiment there is a line at every third bracket of the floating collar. It is no tension on these lines 7 when the sinker tube is at its lowest position, then they are hanging loose at the side of the net cage as shown in 35 Figure 1 and 2. A corresponding number of winches 8 are placed on the floating collar, and an upper end of the lines 7 is fastened to these.

WO 2014/189383 PCT/N02014/050079 7 Upon a need for lifting the net cage, the winches are activated in such a way that the lines are coiled onto a reel (not shown). The winches are connected and synchronized in such a way that they are activated at the same time, and coils equal amount of line at the same time. The lines are led through an aperture 9 in a 5 walkway 10 on the floating collar, where the aperture is performed in such a way that it gives a convenient movement on the line in such a way that it is coiled evenly on the reel as the sinker tube 2 is lifted. The net cage will come upwards together with the sinker tube, and may be collected stage by stage in regular way. 10 When the sinker tube 2 is raised to desired height, the winches 8 are stopped, and the sinker tube will hang in the lines 7. Once the work is performed, the sinker tube is lifted further, eventually lowered again, by activating the winches accordingly. When sinker tube 2 has reached its lower position, and is hanging in the net cage, the winches coils out lines 7 in such a way that they carry no weight. 15

Claims

1. Fish cage comprising floating collar (1), net cage and sinker tube (2), wherein a number of strengthening elements (4, 5) are connected to the net cage, and wherein 5 the sinker tube (2) is connected to the strengthening elements, characterized in that - the strengthening elements comprises vertical strengthening elements (4, 4A) running downwards from the floating collar to the sinker tube, and horizontal strengthening elements (5) running along the circumference of the net cage, as the elements (4, 5) are connected to each other at cross points (11), 10 - the sinker tube (2) is connected to the strengthening elements (4, 5) in such a way that the strengthening elements (4, 5) carry the weight of the sinker tube (2), and - the fish cage comprises a number of lines (7) distributed along the circumference, wherein the lines runs from the floating collar (1) to the sinker tube 15 (2), without carrying the weight of the sinker tube when the sinker tube is in its lower position.

2. Fish cage according to claim 1, characterized in that the horizontal strengthening elements (5) run along the whole circumference of the net cage, and is connected to 20 it.

3. Fish cage according to claims 1 or 2, characterized in that a horizontal strengthening element is placed along the circumference of the net cage, in the transition between net wall and net bottom. 25

4. Fish cage according to any one of the claims 1-3, characterized in that a horizontal strengthening element is placed along the circumference of the net cage, at the fastening to the floating collar. 30

5. Fish cage according to any one of the preceding claims, characterized in that an upper part (4A) of the vertical strengthening elements (4) is not connected to the net cage.

6. Fish cage according to claim 5, characterized in that an upper part (4A) of the 35 vertical strengthening elements (4) is stretching inclined outwards from the net cage, from a cross point (11) with a horizontal strengthening element (5), and upwards to the floating collar (1). WO 2014/189383 PCT/N02014/050079 9

7. Fish cage according to any one of the preceding claims, characterized in that the sinker tube (2) is connected to the strengthening elements (4, 5) by connection means (6). 5

8. System for lifting a sinker tube of a fish cage according to claim 1, characterized by comprising at the least one device (8) for tightening and pulling the lines (7) running from the floating collar (1) to the sinker tube (2), wherein an upper end of the lines is fastened to the device (8) and a lower end is fastened to the sinker tube (2). 10

9. System according to claim 8, characterized in that the lines (7) are carrying the weight of the sinker tube (2) when the sinker tube is lifted or is in a lifted position.

10. System according to claims 8 or 9, characterized in that the lines (7) are loose 15 when the sinker tube (2) is in the lower position.

11. System according to claim 8, characterized in that the device (8) for tightening and pulling the lines is a winch (8) with a reel. 20

12. System according to claim 11, characterized by comprising the same number of winches (8) as lines (7).

13. System according to claim 12, characterized in that the winches (8) are synchronized in such a way that they coil the same amount of line (7) per time, in 25 such a way that the sinker tube (2) is lifted evenly around the fish cage.

14. System according to any one of the claims 8-13, characterized in that the devices are arranged on a walkway (10) on the floating collar. 30

15. System according to claim 14, characterized in that each line (7) is led through an aperture (9) in the walkway, as the aperture is performed in such a way that the line is coiled evenly on a reel of the winch. 35