WO2018056831A1

WO2018056831A1 - Submerged cultivation rig and method of raising or lowering same

Info

Publication number: WO2018056831A1
Application number: PCT/NO2017/050234
Authority: WO
Inventors: Thomas NETLAND
Original assignee: Pe Reefs As
Priority date: 2016-09-20
Filing date: 2017-09-19
Publication date: 2018-03-29
Also published as: NO342970B1; NO20161503A1

Abstract

An artificial seabed (1) for providing a foundation for a marine species cultivation rig (2) wherein the artificial seabed (1) comprises: - an anchoring means (131) for keeping the artificial seabed (1) at a predetermined location with respect to a seabed (5); - a first buoyancy device (11) connected to the anchoring means (131), the first buoyancy device (11) comprising a receptacle provided with at least one inlet for connecting the receptacle to a surface fluid source, and at least one closable drainage means (111) for allowing the replacing of at least a part of a first fluid or a second fluid with the second fluid or first fluid, respectively, the second fluid having a different density to that of the first fluid, so that the buoyancy of the first buoyancy device (11) is changed for allowing the raising and lowering of the first buoyancy device (11) with respect to the seabed (5), The invention also relates to a cultivation rig (2) comprising the artificial seabed (1), a method for moving an artificial seabed (1) in a body of water by altering the buoyancy of the first buoyancy device (11), and a method for moving a cultivation rig (2) in a body of water by altering the buoyancy of the first buoyancy device (11).

Description

SUBMERGED CULTIVATION RIG AND METHOD OF RAISING OR LOWERING SAME

The present invention relates to an artificial seabed for providing a foundation for a marine species cultivation rig.

Cultivation of different marine species such as kelp, mussels, scallops and oysters is believed to have a huge impact on the way we humans look at farming in the future. Sea farming is already an established industry, but the potential for growth is enormous. However, more technological development is needed to fulfil the potential, e.g. to open for efficient farming in new areas and to prevent farming from being a problem for other operations at sea.

It is known from prior art to suspend carriers for marine species in the sea. One example is disclosed in patent NO 328686 B1. The patent discloses a suspended sheet provided with apertures allowing the flow of water from one side of the sheet to the other, the surface of the sheet having a structure that will retain spores and seeds. The patent further discloses an arrangement for suspending such a carrier.

One problem with known technology in the sea farming industry is that carriers for marine species use buoyancy elements on the surface of the sea for suspension purposes. These buoyancy elements may be a hindrance e.g. for shipping. Thus, the use of equipment needing such buoyancy elements may be restricted in certain areas that would otherwise be well suited for sea farming, such as in fjords and other near-shore areas of the sea.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.

The object is achieved through features, which are specified in the description below and in the claims that follow.

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

In a first aspect the invention relates more particularly to an artificial seabed for providing a foundation for a marine species cultivation rig, wherein the artificial seabed comprises: - an anchoring means for keeping the artificial seabed at a predetermined location with respect to a seabed;

- a first buoyancy device connected to the anchoring means, the first buoyancy device comprising a receptacle provided with at least one inlet for connecting the receptacle to a surface fluid source, and at least one ciosable drainage means for allowing the replacing of at least a part of a first fluid or a second fluid with the second fluid or first fluid, respectively, the second fluid having a different density to that of the first fluid, so that the buoyancy of the first buoyancy device is changed for allowing the raising and lowering of the first buoyancy device with respect to the seabed.

The artificial seabed can be raised or lowered by altering the relative proportions of the first fluid and the second fluid within the first buoyancy device. By raising or lowering the artificial seabed, when it functions as the foundation for a marine species cultivation rig, the rig may also be raised or lowered, respectively. By providing the option to raise or lower the rig, it becomes possible to keep the rig completely submerged during cultivation and to raise at least a part of it to the surface when needed, e.g. for harvesting the marine species or maintenance, Furthermore, by adjusting the buoyancy it may be possible to adjust the depth of the artificial seabed and a thereto-connected cultivation net to ensure optimal growth conditions for cultivated marine species growing on the cultivation net. in a preferred embodiment, the first buoyancy device may comprise a first and a second ciosable drainage means. The first ciosable drainage means may be a non-return valve, such as a bail valve, and may be placed in a bottom far end portion of the first buoyancy device, an end that may be arranged to be the lowest point of the first buoyancy device when the first buoyancy device is placed in a sea and when the first buoyancy device is partly filled with air. The first ciosable drainage means may be the drainage means for evacuating the higher density fluid of the first fluid and the second fluid from the first buoyancy device when filling the first buoyancy device with the lower density fluid. The second ciosable drainage means may be placed in a part of the first buoyancy device arranged to be above or near the surface of a sea in which the artificial seabed is placed in operational use. This second ciosable drainage means may be the drainage means for evacuating the lower density fluid of the first fluid and the second fluid when filiing the first buoyancy device with the higher density fluid.

The mix of fluids in the first buoyancy device may be altered by pumping air or water, or any other suitable fluid, through the inlet. This may force fluids present in the first buoyancy device out of the first buoyancy device, either through one or more ciosable drainage means, or through any other outlet that may be comprised by the first buoyancy device. A ciosable inlet may also be comprised by the first buoyancy device, wherein the ciosable inlet is arranged in a position on the first buoyancy device that would normally be under water in operational use. Water may flow through the ciosable inlet into the first buoyancy device to replace a fluid of lower density than water. The inlet may be a valve. The artificial seabed may further comprise a control unit for controlling the alteration of the relative proportions of the first fluid and the second fluid in the first buoyancy device. The artificial seabed may further comprise means for gathering information, such as means for reading the artificial seabed's vertical distance to the surface, means for monitoring temperature, means for monitoring pressure, means for monitoring organic growth, and/or any other suitable means for monitoring conditions for growth for the marine species. By having such features, it takes less manual work to control and monitor the artificial seabed.

The first fluid may be a gas provided by a surface fluid source. The second fluid may typically be seawater. Changing the relative proportions of the first fluid and the second fluid in the first buoyancy device by Increasing the portion of gas provided by the surface fluid source will increase the buoyancy of the first buoyancy device, while an increased portion of seawater will decrease the buoyancy. The first fluid may typically be air. Using air and seawater makes the solution simple and inexpensive, as the two fluids are both abundant and readily available.

The anchoring means of the artificial seabed may comprise weight means capable of withstanding ail buoyancy forces acting. The anchoring means further comprises a connection means for connecting the weight means to the first buoyancy device. Having weighted anchoring means connected to the first buoyancy device will aid in ensuring that the first buoyancy device stays anchored at a chosen location.

The connecting means may be flexible. Furthermore, the connecting means may be any type of means suitable for the purpose, such as a rope or a chain.

As an alternative to a flexible connection means, the connection means may comprise a rigid member. A rigid connection between the weight means and the first buoyancy means may restrict movement of the first buoyancy device relative to the weight means, so that a movement substantially in vertical direction is achieved.

The buoyancy device may be an elongate tubular member. Such an elongate tubular member may provide a highly suitable base of a cultivation rig, as it may allow for anchoring a plurality of cultivation nets in series along the buoyancy device.

The elongate tubular member may be provided with a plurality of weight means mutually spaced along a longitudinal axis of the elongate tubular member. The weight means may be evenly distributed along the length of the first buoyancy device. However, to ensure that the closable drainage means is kept lower that the rest of the first buoyancy device during filling with the fluid of lower density, more weights per unit length or heavier weights are placed at or near the closable draining means than along the rest of the first buoyancy device. This will help ensure that the higher density fluid may be substantially completely evacuated from the artificial seabed.

The artificial seabed may further comprise a second buoyancy device, wherein the second buoy- ancy device is connected to the first buoyancy device and arranged to act as a base for the cultivation rig. With such a second buoyancy device, it may be not necessary to move the first buoyancy device to the surface of the sea to bring the base of the cultivation rig to the surface. The first buoyancy device may sit near the sea floor, while the second buoyancy device may sit relatively ciose to the surface. This may be beneficial with regards to anchoring of the first buoyancy device.

The artificial seabed may comprise one or more further buoyancy devices connected together on top of each other. One or more of the further buoyancy devices may comprise means for altering the buoyancy thereof. A plurality of buoyancy devices with aiterabie buoyancy may provide a more flexible artificial seabed solution, as it may facilitate a more precise adjustment of the depth of the artificial seabed's base for the cultivation rig. in one embodiment, the first buoyancy device is connected to the seabed by anchoring means, wherein a first further buoyancy device with aiterabie buoyancy is connected to the first buoyancy device, a second further buoyancy device with alterable buoyancy is connected to the first further buoyancy device, and the second buoyancy device connected to the second further buoyancy device, wherein the second buoyancy device is the base for a cultivation rig.

In a second aspect, the invention relates to a cultivation rig comprising the artificial seabed of the first aspect of the invention. The cultivation rig may comprise a cultivation net, connected to the artificial seabed, for carrying the marine species to be cultivated. The cultivation rig may further comprise a buoyancy member connected to the cultivation net, for keeping the cultivation net erect when submerged. The buoyancy member may be e.g. a buoy, or it may be any other suitable buoyant object to provide sufficient buoyancy for keeping the cultivation rig substantially erect.

The cultivation rig may comprise a plurality of cultivation nets.

The cultivation rig may further comprise a siiffener for keeping a plurality of cultivation nets and/or buoyancy members spaced apart. By using a stiffener, two or more cultivation nets may be placed side-by-side on the same artificial seabed, as the stiffener will space the nets apart. This may be used to increase the efficiency in terms of production per area. The space between the cultivation nets placed side-by-side provided by the stiffener may better the growth conditions for the marine species to be cultivated. in a third aspect, the Invention relates to a method for moving an artificial seabed according to the first aspect of the invention vertically in a body of wafer, wherein the method comprises the step of moving the artificial seabed verticaiiy in a body of water by altering the buoyancy of the first buoyancy device by altering the relative proportions of the first fluid and the second fluid inside the first buoyancy device. in a fourth aspect, the invention relates to a method for moving a cultivation rig according to the second aspect of the invention vertically in a body of water, wherein the method comprises the step of altering the buoyancy of the first buoyancy device by altering the relative proportions of the first fluid and the second fluid inside the first buoyancy device. in the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

Fig. 1 shows a submerged cultivation rig comprising a first and a second buoyancy device;

Fig. 2 shows the cultivation rig of figure 1 in a semi-submerged position;

Fig. 3 shows in larger scale an end-view of an embodiment of a part of the cultivation rig, wherein three cultivation nets are attached side-by-side on a buoyancy device, wherein the three cultivation nets are separated by stiffeners;

Fig. 4 shows in smaller scale a view from the top of the embodiment of figure 3;

Fig. 5 shows a submerged cultivation rig where the cultivation nets are directly anchored to the first buoyancy device; and

Fig. 6 shows the cultivation rig of figure 5 in a semi-submerged position-

Figure 1 shows a submerged cultivation rig 2 comprising an artificial seabed 1 , the artificial seabed

I comprises a first buoyancy device 1 1 and a second buoyancy device 12. The first buoyancy device 1 1 , in this embodiment an elongate tubular member, is only partly depicted, as only a part of the submerged piece of the device is shown. The buoyancy device 1 1 is in fluid communication with a fluid source (not shown) arranged on shore or on a vessel (not shown). In figure 1 , the first buoyancy device is seen laying on the seabed 5, thus it may be assumed that it is filled with a second fluid, such as water. An anchoring means 131 is shown connected to the first buoyancy device

I I by a connecting means 132. Furthermore, the first buoyancy device 1 1 is provided with a closa- ble drainage means, here shown as a valve 1 1 1. The second buoyancy device 12 is shown connected to the first buoyancy device 1 1.

The cultivation rig 2 further comprises three cultivation nets 21 and six buoyancy members 22, here shown as buoys 22. The cultivation nets 21 are each connected to the second buoyancy device 12, which acts as a base for the cultivation nets 21. Furthermore, each of the cultivation nets 21 are connected to two buoys 22. The second buoyancy device 12 is, due to its buoyancy, kept elevated from the first buoyancy device 1 1.

In figure 2 the first buoyancy device 1 1 has moved up from the seabed 5. This is caused by an increased buoyancy of the first buoyancy device 1 1. In figure 2 the first buoyancy device 1 1 may be filled with air. The cultivation nets 21 have been hoisted above sea level 6 by means of a hoisting device on a vessel (not shown). Figure 3 shows schematicaiiy how three cultivation, nets 21 may be connected to one and the same tubular buoyancy device while being arranged spaced from each other. In the embodiment shown in figure 3, the cultivation nets are connected directly to the first buoyancy device 1 1. The cultivation nets 21 are each connected in a first end 21 1 to a buoy 22, wherein a separate buoy 22 is provided for each cultivation net 21 , Furthermore, the cultivation nets 21 are connected in a second, opposite end 212 to the first buoyancy device 1 1. Figure 3 also shows a stiffener 24 provided for spacing the buoys 22 and the first end 21 1 of the cultivation nets 21 apart.

The same arrangement as in figure 3 is shown in figure 4, here seen from above, in figure 4 it is shown that each cultivation net 21 is connected to two buoys 22, it is to be understood that the arrangement seen in figure 3 and figure 4 is an example of how a plurality of cuitivation nets 21 may be connected side-by-side to one buoyancy device. The buoyancy device used in the figures is the first buoyancy device 1 1 , but it may also be the second buoyancy device 12 or any other buoyancy device suitable for the purpose. It is shown that three cuitivation nets 21 are fixed side-by-side, but other embodiments may have two, four or more than four cuitivation nets 21.

Figures 5 and 6 shows a cultivation rig 2 like the one shown in figure 1 and 2, with the difference that there is no second buoyancy device 12. Instead, the cuitivation nets 21 are directly connected to the first buoyancy device 1 1. in figure 5 the cultivation rig 2 is fuily submerged, with the first buoyancy device 1 1 , being substantially full of water, laying on the seabed 5. in figure 6, the first buoyancy device 1 1 has moved up from the seabed 5 as a result of changes to its buoyancy.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

C l a i m s

1. An artificial seabed (1) for providing a foundation for a marine species cultivation rig (2), c h a r a c t e r i s e d i n that the artificial seabed (1) comprises:

- an anchoring means (131) for keeping the artificial seabed (1) at a predetermined location with respect to a seabed (5);

- a first buoyancy device (11) connected to the anchoring means (131), the first buoyancy device (11) comprising a receptacle provided with at least one inlet for connecting the receptacle to a surface fluid source, and at least one ciosable drainage means (111) for allowing the replacing of at least a part of a first fluid or a second fluid with the second fluid or first fluid, respectively, the second fluid having a different density to that of the first fluid, so that the buoyancy of the first buoyancy device (11 ) is changed for allowing the raising and lowering of the first buoyancy device (11) with respect to the seabed (5).

2. The artificial seabed (1) according to claim 1, wherein the first fluid Is a gas provided by the surface fluid source, and the second fluid is ambient water.

3. The artificial seabed (1) according to claim 1, wherein the anchoring means (131) comprises weight means and a connection means (132) for connecting the weight means to the first buoyance device (11).

4 The artificial seabed (1) according to claim 3, wherein the connecting means (132) comprises a rigid member.

5. The artificial seabed (1) according to any of the preceding claims, wherein the first buoyance device (11) is an elongate tubular member.

6. The artificial seabed (1) according to any one of the preceding claims, wherein the artificial seabed (1) further comprises a second buoyancy device (12) arranged to be connected to the first buoyancy device (11) and arranged to act as a base for the cultivation rig (2).

7. A cultivation rig (2) comprising the artificial seabed (1) according to any of the preceding claims, wherein the cultivation rig (2) further comprises a cultivation net (21) connected to the artificial seabed (1), and a buoyancy member (22), for keeping the cultivation net (21) erect when submerged in water.

8 The cultivation rig (2) according to claim 7, further comprising a stiffener (24) for keeping a plurality of cultivation nets (21) and/or buoyancy members (22) arranged side-by-side spaced apart.

9. A method for moving an artificial seabed (1 ) according to any one of the claims 1 to 6 vertically in a body of water, c h a r a c t e r i s e d i n that the method comprises the step of altering the buoyancy of the first buoyancy device (11 ) by altering the relative proportion of the first fluid and the second fluid inside the first buoyancy device (11).

10. A method for moving a cultivation rig (2) according to claims 7 or 8 vertically in a body of water, c h a r a c t e r i s e d i n that the method comprises the step of altering the buoyancy of the first buoyancy device (11) by altering the relative proportion of the first fluid and the second fluid inside the first buoyancy device (11),