NO348093B1

NO348093B1 - Floating closed fish pen assembly

Info

Publication number: NO348093B1
Application number: NO20221377A
Authority: NO
Inventors: Knut Solberg
Original assignee: Solinova As; Vitamar AS
Priority date: 2022-12-21
Filing date: 2022-12-21
Publication date: 2024-08-12
Also published as: NO20221377A1

Description

FLOATING CLOSED FISH PEN ASSEMBLY

Technical Field

[0001] The present invention relates to a floating, closed aquaculture pen assembly suitable for fish farming.

Background Art

[0002] Closed and semi-closed fish pens have seen increased use. These types of fish pens, provided with a flexible and impermeable sheet, reduce problems related to lice by pumping fresh water from sea depths where the lice are not present.

Further advantages are low risk of escape and the possibility to collect sludge and feed residuals.

[0003] However, such known types of closed fish pens require a certain depth, because the bottom of the pen is normally made relatively steep, preferably 45° or even steeper. The steep bottom section of known pens of the type discussed herein makes it difficult to obtain large volumes at shallow water depths, such as only 20 to 25 meters.

[0004] Publication NO20110254 discloses a closed fish pen attached to a floating arrangement. The fish pen has an inner net surrounded by a closed outer wall. As an alternative, the publication suggests having the net outside and the closed outer wall inside.

[0005] Publication NO20130649 presents a closed fish pen having a closed bag surrounded by a safety net on its outside.

[0006] WO2022191716 also discloses a closed fish pen having a net arranged inside a closed flexible outer barrier, such as a tarpaulin.

Summary of invention

[0007] According to the present invention, there is provided a floating, closed fish pen assembly comprising a sheet arrangement with a flexible, water-impermeable or substantially water-impermeable sheet. The sheet arrangement comprises a side sheet, and a bottom sheet. The fish pen assembly further comprises a floating arrangement, a pump assembly maintaining an elevated inner water level inside the sheet arrangement, a support arrangement that is connected to the floating arrangement and that comprises a side support and a bottom support means. The bottom sheet abuts against and is supported by the bottom support means. The support arrangement further comprises a rigid support ring that connects to the side support and to the bottom support means. The shape of the bottom sheet is substantially flat, extending in a horizontal direction, or the bottom sheet is coneshaped with a lower cone apex, wherein a bottom angle between the horizontal and a portion of the bottom sheet extending between the lower cone apex and the side sheet, is below 30°.

[0008] By stating that the fish pen assembly is a floating fish pen assembly, it is meant that it floats in a body of water, as in the sea or in a lake, or the like.

[0009] The elevated inner water level is maintained above the water level outside the sheet arrangement, i.e. above the vertical level of the sea surface. This provides a pressure drop over the sheet arrangement.

[0010] When stating that the sheet arrangement has a water-impermeable sheet, it is meant that it is substantially watertight. This prevents contaminants, such as lice and algae, from entering through the sheet arrangement.

[0011] Moreover, by stating that the fish pen assembly is a closed assembly, it is meant that the water supply into and the water outflow from the fish pen assembly is controlled at least partly by the pump assembly. In this manner, the operator can control the quality of water that enters the fish pen.

[0012] By means of the support arrangement, the fish pen assembly can have a sheet arrangement with a substantially flat or less steep cone-design. This is because forces will be transferred from the sheet arrangement to the support arrangement. The sheet arrangement will, moreover, be less prone to rupture and excessive tension as a result of the reduced forces.

[0013] The rigid support ring will contribute to maintaining a desired shape of the support arrangement, and thus of the supported sheet arrangement.

[0014] Preferably, the said angle can below 20° or below 15°.

[0015] The floating arrangement can in some embodiments have a rectangular shape. In other embodiments it may have other polygonal shapes, for instance the shape of an octagon. A circular (ring) shape is also possible.

[0016] In some embodiments, bottom support means comprises a mesh extending below and supporting the bottom sheet. Preferably, in embodiments comprising the said rigid support ring, the bottom support means is supported by and extending across the rigid support ring.

[0017] The fish pen assembly may further comprise a securing means extending between the rigid support ring and the bottom sheet, such that the bottom sheet is maintained at a constant radial distance within the rigid support ring. In this manner, the shape of the sheet arrangement can be maintained during periods of current, large waves, etc.

[0018] The fish pen assembly can comprise an upper ring structure with a sheet attachment ring to which the side sheet connects. The upper ring structure can be supported from below by the floating arrangement.

[0019] In such embodiments, the fish pen assembly may further comprise one or more hinge attachments that attach the upper ring structure to the floating arrangement and that allows for a mutual pivoting movement between the upper ring structure and the floating arrangement about a substantially horizontal axis. Further it may comprise sliding supports with contact faces fixed to the floating arrangement, which support the upper ring structure in a sliding manner.

[0020] The fish pen assembly may further comprise an auxiliary side barrier arranged outside the side sheet. The auxiliary side barrier can be arranged as a safeguard against escape of fish from the pen, such as if a rupture or the like occurs in the sheet arrangement.

[0021] In such embodiments, the auxiliary side barrier and the bottom support means can be part of an auxiliary barrier arrangement that encloses the sheet arrangement.

[0022] The auxiliary barrier arrangement thus constitutes a safeguard against escape in a case where the sheet arrangement has ruptured or been otherwise damaged.

[0023] In some embodiments, the floating arrangement can exhibit a polygonal shape, for instance an octagonal shape. The fish pen assembly can further comprise a reinforcement means fixed to the upper part of the side sheet, and further an attachment means that connects the floating arrangement to the side sheet at the position of the reinforcement means. Such embodiments allow the floating arrangement to have a non-circular shape that results in a horizontal distance between the side sheet and the floating arrangement at some locations, while reducing the risk of tear in the side sheet.

[0024] In some embodiments, the floating arrangement may comprise an overhang at the interior side, to reduce contact wear between the side sheet and the floating arrangement.

[0025] The fish pen assembly may in some embodiments further have a net for prevention of escape of jumping fish, wherein the net is attached to or is part of said attachment means.

Detailed description of the invention

[0026] While various features of the invention have been discussed in general terms above, a more detailed and non-limiting example of embodiment will be presented in the following with reference to the drawings, in which

Fig. 1 is a schematic side-view of a fish pen assembly according to an embodiment of the invention;

Fig. 2 is a top view showing a fish pen assembly from above;

Fig. 3 is an enlarged portion of the side-view shown in Fig.1;

Fig. 4 is another top view of a fish pen assembly, illustrating an embodiment of the support arrangement;

Fig. 5 is a schematic side-view of another embodiment of the fish pen assembly;

Fig. 6 is an enlarged, schematic cross section side-view illustrating an embodiment of the bottom support means of the fish pen assembly;

Fig. 7 is a top view of another embodiment of the fish pen assembly;

Fig. 8 is a top view of a plurality of fish pen assemblies joined together;

Fig. 9 is a side view of another embodiment of the fish pen assembly;

Fig. 10 is a cross section view showing the floating arrangement at a horizontal distance from the vertical part of a side sheet ;and

Fig. 11 is a cross section corresponding to Fig.10, however showing substantially no horizontal distance between the floating arrangement and the vertical part of the side sheet.

[0027] Fig. 1 depicts a fish pen assembly 1 according to an embodiment of the present invention. The fish pen assembly 1 comprises a floating arrangement 3 that floats at the sea surface 5.

[0028] A flexible and water impermeable side sheet 7, such as a fabric or tarpaulin, depends substantially vertically down from the floating arrangement 3. The side sheet 7 is part of a sheet arrangement 10, that holds a volume of water. The sheet arrangement 10 thus also comprises a bottom sheet 9 that connects to the side sheet 7.

[0029] The sheet arrangement 10 can typically contain between 10000 and 30000 m<3 >of water, but may also contain less or more than this range.

[0030] During normal operation, an inner water level 11 at the upper part of said water volume is at a higher vertical level than the sea surface 5. Consequently, at a given vertical level, the hydrostatic pressure inside the sheet arrangement 10 is higher than outside the sheet arrangement 10. Thus, if the inner water level 11 is, for instance, 0,1 m above the sea surface 5, the pressure difference over the sheet arrangement 10 will be approximately 0,01 bar.

[0031] If the sheet arrangement 10 is damaged, such as with a small tear, this pressure difference will ensure that surrounding water will not flow into the sheet arrangement 10. In this manner, one prevents contaminants, such as lice, from entering the sheet arrangement 10.

[0032] The elevated inner water level 11 can be provided by use of a pump assembly 43, as will be appreciated by the skilled reader. As shown in Fig.1, the pump assembly 43 is part of a water supply arrangement 40. The water supply arrangement 40 further comprises a water inlet pipe 41 and a water outlet pipe 45.

[0033] In the shown embodiment, the bottom sheet 9 comprises an outlet 13 at a bottom and lowermost portion of the bottom sheet 9.

[0034] In particular, the bottom sheet 9 is, in the shown embodiment, designed with a coned shape, wherein the cone apex 9a constitutes the lowermost part of the bottom sheet 9.

[0035] Depending down from the floating arrangement 3 is a support arrangement 20. The support arrangement 20 comprises side supports 21 that extend downwards along the side sheet 7. The side supports 21 can comprise a plurality of wires, ropes, chains, and similar means. In the shown embodiment, the side supports 21 are connected to the floating arrangement 3 at their upper ends. At their lower portion, they are connected to a rigid support ring 23.

[0036] The support arrangement 20 further comprises a bottom support means 25 that connects to the rigid support ring 23. The bottom support means 25 can comprise a plurality of wires, ropes, chains, or similar devices. Alternatively, the bottom support means 25 can comprise a net, or one or more rigid plates.

[0037] As shown in Fig.1, the bottom sheet 9 and the bottom support means 25 are parallel. Although drawn somewhat apart in Fig.1, the bottom support means 25 is configured to support the bottom sheet 9. In other words, the bottom sheet 9 will abut and rest against the bottom support means 25. This is at least partly due to the higher hydrostatic pressure inside the sheet arrangement 10 than outside the sheet arrangement 10.

[0038] Fig. 2 depicts the fish pen assembly 1, seen from above. The floating arrangement 3 comprises a plurality of floating units 3a that together form a rectangular or square shape. Stiffening beams 17 are arranged, bridging the corners of the rectangular shape.

[0039] The rectangular or square shape of the floating arrangement 3 facilitates interconnection of several adjacent fish pen assemblies 1 according to the invention. This is because the elongated edges of the rectangular shape will fit with the elongated shape of an adjacent fish pen assembly 1. Alternatively, one may even employ one elongated part of the floating arrangement 3 commonly for two adjacent fish pen assemblies 1. This topic will be discussed further below, with reference to Fig. 8.

[0040] An upper ring structure 30 is supported by the floating arrangement 3. The upper ring structure 30 comprises a walkway 31 for facilitating personnel access. Moreover, it comprises a sheet attachment ring 33, to which the sheet arrangement 10 is attached.

[0041] In the shown embodiment, the stiffening beams 17 connect directly to the floating units 3a. However, in other embodiments they may be part of the upper ring structure 30, thus contributing in maintaining the stiffness of the upper ring structure 30.

[0042] The upper ring structure 30 is attached to the floating arrangement 3 with two hinge attachments 34. The hinge attachments 34 fix the upper ring structure 30 to the floating arrangement 3 but allow the upper ring structure 30 to pivot about a substantially horizontal axis. Such pivoting movements can typically occur during waves or uneven loads acting on the floating arrangement 3.

[0043] In addition to the said hinge attachments 34, the upper ring structure 30 is supported on the floating arrangement 3 through sliding supports 36. The sliding supports 36 comprise respective contact faces fixed to floating arrangement 3, against which the upper ring structure 30 can slide during movement.

[0044] Fig. 3 depicts an enlarged portion of Fig.1 in better detail. In the shown embodiment, the rigid support ring 23 has a circular cross section. It may however have another design, for instance a rectangular cross section.

[0045] The rigid support ring 23 can be made of any suitable material, for instance steel or another metal. Alternative materials include composite materials, such as GRP.

[0046] Since, as briefly discussed above, the bottom sheet 9 will contact and rest on the bottom support means 25, the side sheet 7 will not have to adsorb the vertical forces resulting from the pressure onto the bottom sheet 9. Instead, the side sheet 7 will only need to adsorb tangential forces in the horizontal plane.

[0047] The vertical forces present due to the higher level of the inner water level 11 will be adsorbed by the side support 21. In particular, these forces are transmitted from the bottom support means 25, through the rigid support ring 23, and into the side support 21.

[0048] Still referring to Fig.3, a securing means 15, for instance a plurality of ropes or similar, connects the rigid support ring 23 to the sheet arrangement 10. In the shown embodiment, the securing means 15 extends between the rigid support ring 23 and the interface between the side sheet 7 and the bottom sheet 9.

[0049] Thus, the diameter of the rigid support ring 23 is larger than the diameter of the bottom sheet 9.

[0050] Notably, while the bottom sheet 9 abuts against the bottom support means 25, the side sheet 7 does not contact the side support 21.

[0051] Fig. 4 shows a view similar to Fig.2, however without the sheet arrangement 10. The side support 21 is illustrated with a plurality of ropes extending down from the floating arrangement 3 and to the rigid support ring 23.

[0052] Moreover, the bottom support means 25 comprises a plurality of ropes that extend across the area defined by the rigid support ring. These ropes will counteract the downwardly directed forces from the bottom sheet 9, resulting from the pressure drop over the bottom sheet 9.

[0053] The side support 21 and/or the bottom support means 25 can advantageously comprise ropes made of PE fibers (e.g. UHWPE fibers branded under the name Dyneema). Other embodiments may include wires or other types of similar elongated means.

[0054] The configuration of the side support 21, such as the number of and the strength of each rope or the like, will depend on various parameters, such as the height of the inner water level 11. Preferably, the side support 21 is attached to the rigid support ring 23 at approximately equal distances between the respective ropes (or the like). Furthermore, the side support 21 is preferably attached to the floating arrangement 3 at a position that lets the floating arrangement 3 maintain a substantially horizontal orientation. Typically, and as indicated in Fig.1, the side support 21 can thus connect to a mid-portion of the floating arrangement 3. In this manner, the orientation of the floating arrangement 3 can remain constant even during varying downward pulling force from the side support 21.

[0055] In some embodiments, instead of using a net, ropes, wires or the like, the bottom support means 25 can include rigid plates.

[0056] Fig. 5 is a schematic side-view of an embodiment resembling the embodiment shown in Fig.1. However, the side support 21 comprises pairs of ropes (or wires, or similar) that extend from the floating arrangement 3 down to the rigid support ring 23 at different angles. In the shown embodiment, the two ropes of each pair of rope are connected to the floating arrangement 3 at an outer and at an inner position, respectively, of the floating arrangement 3. This contributes to maintaining the support ring 23, and hence the bottom sheet 9, at a correct position with respect to the floating arrangement 3, and at the same time keeping the floating arrangement in an horizontal position, despite water currents, waves, or wind that may affect this mutual position.

[0057] The bottom support means 25, and the abutting bottom sheet 9, may be flat, i.e. extending in a horizontal direction. However, as shown in the embodiments discussed herein, they may also have a coned shape. Fig.6 illustrates a bottom angle α of a cross section of the bottom support means 25 and the bottom sheet 9. The bottom angle α can advantageously be below 30°, 20°, or even 15° with respect to the horizontal direction (which is indicated with the dashed line). In other words, a rope extending between the outlet 13 (or the cone apex 9a) and the rigid support ring 23, will have an angle of less than 15° with the horizontal.

[0058] Fig. 7 depicts a top view of an embodiment similar to the embodiment shown in Fig.1. The floating arrangement 3 comprises several, eight in this embodiment, floating units 3a that are assembled together to form a polygonal form.

[0059] Also shown in Fig.7 are a plurality of water supply arrangements 40. The water supply arrangements 40 respectively comprise a water inlet pipe 41, a pump assembly 43, and a water outlet pipe 45. The water outlet pipe 45 is arranged such that the supplied water is delivered inside the sheet arrangement 10. The pump assembly 43, which was schematically depicted in Fig.1, can typically be integrated with the water inlet pipe 41 and is thus not visible in Fig.7.

[0060] Fig. 8 is a top view illustrating a plurality of fish pen assemblies 1 joined together. As the skilled reader will appreciate, some parts of the floating arrangement 3 is shared by adjacent fish pens.

[0061] Fig. 9 is a side view of a fish pen assembly 1 similar to the embodiment shown in Fig.1. However, in this embodiment, the fish pen assembly 1 further comprises an auxiliary side barrier 27. The auxiliary side barrier 27 extends between the floating arrangement 3 and the bottom support means 25. In embodiments comprising the rigid support ring 23, the auxiliary side barrier 27 can advantageously connect to the rigid support ring 23. The auxiliary side barrier 27 is not water impermeable. It can typically be in the form of a net. However, it shall be fine-meshed to such an extent that fish cannot escape through it. Hence, in case of a rupture or other occurrence with the sheet arrangement 10, the auxiliary side barrier 27 will prevent fish from escaping.

[0062] Moreover, in embodiments comprising the auxiliary side barrier 27, the bottom support means 25 can also be fine-meshed to such extent that fish will not escape through it. In such embodiments, the auxiliary side barrier 27 and the bottom support means 25 together form an auxiliary barrier arrangement 50 that encloses the sheet arrangement 10.

[0063] Fig. 10 and Fig.11 are cross section views through the floating arrangement 3, similar to the floating arrangement 3 shown in Fig.1. Moreover, Fig.10 and Fig.11 illustrate an embodiment wherein the floating arrangement 3 has a polygonal shape, such as the octagonal shape shown in Fig.7. Notably, in the embodiment shown in Fig. 10 and Fig.11, the sheet arrangement 10 is attached to and supported from the floating arrangement 3.

[0064] Since the side sheet 7 of the sheet arrangement 10 has a substantially circular shape, the horizontal distance between the side sheet 7 and the floating arrangement 3 will vary along its circumference. In particular, at the interior corners of the polygonal shape, the horizontal distance will be largest. On the contrary, at the midpoint between the interior corners, the horizontal distance will be smallest and can be substantially zero.

[0065] Fig. 10 depicts the position at an interior corner of the polygonal shape. The side sheet 7 is attached to the floating arrangement 3 by means of an attachment means 8. The attachment means 8 can be of various types, for instance a pluralty of ropes.

[0066] As indicated with the horizontal arrow in Fig.10, the attachment means 8 pulls in the upper part of the side sheet 7 with a force that has a horizontal component. To prevent damage to the side sheet 7, such as tear, the sheet arrangement 10 comprises a reinforcement means 12 that extends with a horizontal circular configuration along the circumference of the side sheet 7. The reinforcement means 12 can for instance be in form of a rope or a wire fixed to the side sheet 7.

[0067] In the embodiment shown in Fig.10 and in Fig. 11, the floating arrangement 3 comprises an overhang 14 that prevents the side sheet 7 from rubbing against the floating arrangement 3. Such rubbing could result in wear of the side sheet 7. In the shown embodiment, the overhang 14 is provided by an inwardly inclining inner wall of the floating arrangement 3. The skilled person will however appreciate that other embodiments for providing the overhang 14 is possible, such as a step in an otherwise vertical interior wall.

[0068] The fish pen assembly 1 can advantageously comprise a net (not shown) that is fixed to the attachment means 8, to prevent escape of fish that jumps out of the water above the water surface. Alternatively, the attachment means 8 itself can be in the form of such a net.

Claims

1. A floating, closed fish pen assembly (1) comprising

- a sheet arrangement (10) with a flexible, substantially water-impermeable sheet, the sheet arrangement comprising a side sheet (7), and a bottom sheet (9);

- a floating arrangement (3, 3a);

- a pump assembly (43) maintaining an elevated inner water level (11) inside the sheet arrangement (10);

- a support arrangement (20) connected to the floating arrangement (3) and comprising a side support (21) and a bottom support means (25); wherein the bottom sheet (9) abuts against and is supported by the bottom support means (25),

characterized in that the support arrangement (20) further comprises a rigid support ring (23) that connects to the side support (21) and to the bottom support means (25); and

- that the shape of the bottom sheet (9) is flat, extending in a horizontal direction; or

- that the bottom sheet (9) is cone-shaped with a lower cone apex (9a), wherein a bottom angle (α) between the horizontal and a portion of the bottom sheet extending between the lower cone apex (9a) and the side sheet (7), is below 30°.

2. A fish pen assembly (1) according to claim 1, characterized in that the floating arrangement (3) has a rectangular shape.

3. A fish pen assembly (1) according to any one of the preceding claims, characterized in that the bottom support means (25) comprises a mesh or rigid plates extending below and supporting the bottom sheet (9).

4. A fish pen assembly (1) according to any one of the preceding claims, characterized in that it further comprises a securing means (15) extending between the rigid support ring (23) and the bottom sheet (9), such that the bottom sheet is maintained at a constant radial distance within the rigid support ring (23).

5. A fish pen assembly (1) according to any one of the preceding claims, characterized in that it comprises an upper ring structure (30) with a sheet attachment ring (33) to which the side sheet (7) connects, wherein the upper ring structure (30) is supported from below by the floating arrangement (3).

6. A fish pen assembly (1) according to claim 5, characterized in that it further comprises

- one or more hinge attachments (34) that attach the upper ring structure (30) to the floating arrangement (3) and that allows for a mutual pivoting movement between the upper ring structure (30) and the floating arrangement (3) about a substantially horizontal axis; and

- sliding supports (36) with contact faces fixed to the floating arrangement, which support the upper ring structure in a sliding manner.

7. A fish pen assembly (1) according to any one of the preceding claims, characterized in that it further comprises an auxiliary side barrier (27) arranged outside the side sheet (7).

8. A fish pen assembly (1) according to claim 7, characterized in that the auxiliary side barrier (17) and the bottom support means (25) are part of an auxiliary barrier arrangement (50) that encloses the sheet arrangement (10).

9. A fish pen assembly (1) according to one of the preceding claims, characterized in that the floating arrangement (3) exhibits a polygonal shape, and that the fish pen assembly further comprises a reinforcement means (12) fixed to the upper part of the side sheet (7) and an attachment means (8) that connects the floating arrangement (3) to the side sheet (7) at the position of the reinforcement means (12).

10. A fish pen assembly (1) according to one of the preceding claims, characterized in that the floating arrangement (3) comprises an overhang (14) at the interior side, to reduce contact wear between the side sheet (7) and the floating arrangement (3).

11. A fish pen assembly (1) according to claim 9, characterized in that it further comprises a net for prevention of escape of jumping fish, wherein the net is attached to or is part of said attachment means (8).