The present invention relates to a buoyancy module for an aquaculture pumping system, comprising a pipe section, a buoyancy unit having a density lower than that of water, a first fastening component for securing a first section of a hose to a first end section of the pipe section, and a second fastening component for securing a second section of the hose to a second end section of the pipe section.

The present invention also relates to an aquaculture pumping system comprising such a buoyancy module.

The present invention further relates to a method of mounting an aquaculture buoyancy module onto a hose of an aquaculture pumping system, and to use of such a buoyancy module.

GB2498667A discloses a pumping system for collecting sunken waste from the bottom of an aquaculture cage. The sunken waist may for example be unconsumed feed, faeces and morts, i.e. dead marine organism, e.g. dead fish. Within the industry, such a system is sometimes referred to as a mort collection system.

The pumping system disclosed in GB2498667A includes a suction head positioned at the bottom of the cage. The system also includes a hose which runs from the suction head to the surface of the body of water in which the cage is positioned. By injecting air into the suction head and/or the hose, sunken waste accumulated at the bottom of the cage will be sucked into the suction head and raised to the surface by means of injected air rising in the hose.

In order to prevent the hose from collapsing and folding when the injection of air is switched of, a combined pipe section with an integral float is coupled onto the hose. The coupling onto the hose is accomplished by threading an upper and a lower hose portion of the hose onto a first and a second end of the pipe section, respectively, and attaching the hose portions to the pipe section by means of fastening

components, e.g. hose clamps.

The outer surface of the integral float may be formed with rounded edges and corners, such that entanglement of the integral float with cage structures such as cage walls, feed lines, moorings etc. is avoided. However, a problem associated with the combined pipe section and integral float, is that the fastening components may still cause such entanglement. In particular, if the fastening components are caught in the cage walls they may cause serious damage and, potentially, allow large numbers of fish to escape from the cage. A principal aim of the present invention is to at least alleviate this problem and provide a buoyancy module which reduces the risk of the fastening components damaging other cage structures. A further aim of the invention is to provide such a buoyancy module which is easy to install and which has few parts.

The buoyancy module according to the invention is characterised in that the buoyancy unit is connectable to the pipe section after connection of the hose to the pipe section, and in that the buoyancy unit, when connected to the pipe section, covers the first and second fastening components.

The aquaculture pumping system according to the invention is characterised in that the buoyancy module is connected to the hose at a predetermined distance above the suction head for keeping the hose standing substantially upright in the body of water.

The method according to the invention comprises the steps of:

using a first fastening component, securing a first section of the hose to a first end section (16a) of the pipe section,

using a second fastening component, securing a second section of the hose to a second end section of the pipe section,

covering the first and second fastening component with the buoyancy unit, and

connecting the buoyancy unit to the pipe section.

Unlike prior art aquaculture buoyancy modules, the buoyancy module according to the invention is not made as a combined pipe section and integral buoyancy unit. In fact, since the buoyancy unit according to the invention is connected or secured to the pipe section after the hose has been secured to the pipe section, the buoyancy unit cannot be made integral with the pipe section.

In the aquaculture pumping system, the buoyancy module can be positioned on the surface or further down in the body of water.

The buoyancy unit can be made from any material providing sufficient lift to the buoyancy unit to hold the hose standing substantially upright in the body of water, e.g. float foam, cork material or polystyrene material. The buoyancy unit may also or alternatively be provided with one or a plurality of gas or air- filled cavities. For example, it may be advantageous to make the buoyancy unit from a rigid, dimensionally stable polymer, e.g. polyethylene, forming an air-filled cavity, and it may be advantageously be produce such a buoyancy unit using rotational moulding or pressure injection moulding techniques.

It may be advantageous to make the buoyancy unit releasably connectable to the pipe section, thus allowing the buoyancy unit to be released from the pipe section and also allowing subsequent release of the hose from the first and second fastening components. The buoyancy unit may advantageously comprise a generally annular float which encircles the pipe section when connected thereto.

The float may advantageously comprise first and second semi-annular float sections allowing the float sections to be straddled over the pipe section when the float is mounted to the pipe section.

Each first and second semi-annular float sections may advantageously comprises an air-filled cavity providing buoyancy to the float section.

The first and second semi-annular float sections may advantageously be made from a rigid, dimensionally stable polymer, e.g. polyethylene. The mantle surface of the pipe section may advantageously comprise an annular recess, and the float may advantageously comprise an inner, annular protrusion extending radially into an axial through-channel of the float for locking into the annular recess.

The buoyancy unit may advantageously be connectable to the pipe section by means of bolt joints.

In the following, a non-limiting embodiment of the invention will be disclosed in more detail with reference to the appended drawings.

Fig. 1 is a schematic representation of an aquaculture cage structure comprising a pumping system according to the invention. Fig. 2 discloses an embodiment of a buoyancy module according to the invention.

Fig. 3 discloses that buoyancy module according to Fig. 2 in a side view.

Fig. 4 is a sectional view of the buoyancy module according to Fig. 2 as indicated by the section IV-IV in Fig. 3.

Fig. 5 is a top view of the buoyancy module according to Fig. 2. Fig. 6 is an exploded view of the buoyancy module according to Fig. 2.

Fig. 7 discloses the buoyancy module according to Fig. 2 mounted to a hose of an aquaculture pumping system.

Fig. 8 is a sectional view of the buoyancy module and the hose disclosed in Fig. 7.

Fig. 1 discloses a floating aquaculture cage structure 1 for retained aquaculture fish 2. The cage structure 1 comprises a ring-shaped floating tube 3 which floats on a surface 4 of a body of water 5. From the tube 3 there is suspended an aquaculture cage 6 which comprises a cylinder-shaped wall section 7 and a funnel-shaped bottom section 8. The cage 6 may advantageously be fabricated from a netting material, e.g. fibre or metal netting, or a fabric.

The cage structure 1 further comprises a pumping system 9 for removing sunken waste from the bottom of the cage 6. The pumping system 9 comprises a suction head 10 positioned inside the cage 6 at the bottom section 8, and a hose 1 1 which runs from the suction head 10 to a waste receiving station 12 located at or above the surface 4 outside of the cage 6. The pumping system 9 also comprises an air injection conduit 13 for injecting air into the suction head 10 and/or the hose 1 1 , whereby sunken waste accumulated at the bottom section 8 will be sucked into the suction head 10 and raised to the receiving station 12 by means of the injected air rising in the hose 1 1.

At the receiving station 12, the raised mixture of waste and water is separated, e.g. in a sieve box 14, after which the waste is directed to suitable processing or destruction. The pumping system 9 further comprises a buoyancy module 15 which is coupled to the hose 1 1 at a predetermined position between the surface 4 and the suction head 10 in order to hold the hose 1 1 substantially in an upright orientation in the body of water 5 also when the injection of air is switched of.

Figs. 2-7 disclose an embodiment of the buoyancy module 15. The buoyancy module 15 comprises a pipe or pipe section 16 and a buoyancy unit 17 which, in the present embodiment, comprises two identical floats 17a, 17b.

The pipe section 16 has a generally circular cross-section and comprises a first end section 16a and a second end section 16b where the mantle surface of the pipe section 16 displays annular recesses 20a, 21 a, 20b, 21b. Each float 17a, 17b is generally rotational-symmetric and discloses an axial, through-going opening or channel 18. At one axial end, the float 17a, 17b comprises an inner, annular protrusion 29 extending radially into the channel 18.

Each float 17a, 17b comprises two identical, semi-annular first and second float sections 22, 23 which, when joined together, render the float 17a, 17b its generally annular shape. The float sections 22, 23 are releasably connected to each other by means of bolt joints. Each bolt joint comprises a bolt 24 which runs through a trough-going bore 25 in one float section of a float section pair and attaches to a complementary threaded blind bore or an embedded nut 26 in the other float section of the float section pair. At the bore entrance, the through-going bore 25 is counter- sunk such that the head of the bolt 24 will not protrude above the surface of the float 17a, 17b when the bolt joint is formed. In the disclosed embodiment, the bolt joint also comprise a washer 27 which prevents deformation of the trough-going bore 25 when the bolt joint is tightened.

As is evident from e.g. Fig. 6, each float section 22, 23 comprises a semi-annular protrusion 28. When two float sections 22, 23 are joined together, the semi-annular protrusions 28 form the annular protrusion 29 of the float 17a, 17b.

Each float section 22, 23 comprises an internal, air-filled cavity 19 which provides buoyancy to the float section.

The process of mounting the buoyancy module 15 in the pumping system 9 comprises the steps of mounting the pipe section 16 to the hose 1 1 and subsequently mounting the floats 17a and 17b onto the pipe section 16.

The step of mounting the pipe section 16 to the hose 1 1 comprises threading or otherwise arranging a first, upper section 1 la of the hose 1 1 onto the first end section 16a of the pipe section 16 and securing the hose section 1 la to the end section 16a by means of a first fastening component 30a, e.g. a first pair of hose clamps which encircle the hose section 1 1a and lock into the recesses 20a, as is disclosed in Fig. 8. In the same way, a second, lower section 1 lb of the hose 1 1 is threaded or otherwise arranged onto the second end section 16b of the pipe section 16 and secured to the end section 16b by means of a second fastening component 30b, e.g. a second pair of hose clamps which encircle the hose section 1 lb and lock into the recesses 20b.

After the hose sections 1 1a, 1 lb have been secured to the pipe section 16, the floats 17a, 17b are secured to the pipe section 16. This comprises positioning a pair of float sections 22, 23 around the pipe section 16 over each of the end sections 16a and 16b such that the semi-annular protrusions 28 are brought into the recesses 21a and 21b, respectively, and subsequently joining the float sections in each pair together by means of the above-disclosed bolt joints. Once the float sections in each pair are secured to each other, the now newly-formed annular protrusions 29 will be in locking engagement with the annular recesses 21a and 21b, respectively, as is disclosed in Fig. 8. This will prevent the floats 17a, 17b from sliding in the axial direction of the pipe section 16 when the pumping system is deployed.

As is evident from Fig. 8, the inner diameter of the through-channel 18 of the floats 17a, 17b is larger than the outer diameter of the pipe section 16. This provides an annular space 31a, 31b between the floats 17a, 17b and the pipe section 16, which annular space 31a, 31b is sufficient to harbour the hose clamps 30a, 30b.

Consequently, once mounted on the pipe section 16, the floats 17a, 17b will cover the hose clamps 30a, 30b and prevent them from snagging or otherwise becoming entangled with cage walls, feed lines, moorings etc., thus preventing the hose clamps 30a, 30b from damaging cage structures. It is to be noted that the bolt joints allow the floats 17a, 17b, to be released from the pipe section 16 such that the hose clamps 30a, 30b are once again exposed. This allows the pipe section 16 to be released from the hose 1 1 and repositioned.

The pipe section 16 is advantageously made from a rigid, dimensionally stable polymer, e.g. polyethylene. However, other rigid, dimensionally stable materials can be used, e.g. metal.

Advantageously, the float sections 22, 23 are also made from a rigid, dimensionally stable polymer, e.g. polyethylene, and may advantageously be made by rotational moulding or pressure injection moulding. Above, a non-limiting embodiment of the invention has been discussed. It is to understood, however, that other embodiments, versions or variants are possible within the scope of the claims. For example, instead of two floats, it is understood that the buoyancy unit may comprise one, three or any other number of floats as long as they cover the fastening components when connected or mounted to the pipe section. Also, it is understood that alternative means of connecting the buoyancy unit to the pipe section is possible other than the above-disclosed fastening components in the form of hose clamps.

Also, it is understood that the above-disclosed float sections may be connected to each other by other means that the above-disclosed counter-sunk bolts 24 and nuts 26. For example, the float sections may be connected to each other by means of strappings or inter-locking sections. It is advantageous, however, that the means for securing the float sections to each other are such that entanglement of the float with cage structures such as cage walls, feed lines, moorings etc. is avoided.

Furthermore, it is understood that the float does not necessarily need to define an annular space for harbouring the fastening components. When mounted, the float may very well be arranged such that it is in contact with or even tightly surrounds the fastening components, in which case the inner radius of the float may be constant. In such an embodiment, the inner wall of the float may be made from an elastic material such that the inner wall can adopt to the form of the fastening means and tightly surround the same.