NO20210980A1

NO20210980A1 - A connection structure connecting two elements of a floating breakwater structure

Info

Publication number: NO20210980A1
Application number: NO20210980A
Authority: NO
Inventors: Geir Grimsrud; Truls Malm
Original assignee: Fred Olsen Renewables As
Priority date: 2021-08-16
Filing date: 2021-08-16
Publication date: 2023-02-17
Also published as: WO2023022599A1

Description

A CONNECTION STRUCTURE CONNECTING TWO ELEMENTS OF A FLOATING BREAKWATER STRUCTURE

Technical Field

[0001] The present invention relates to breakwater structures, i.e. protective structures to protect installations from waves. In particular the invention relates to floating tubular devices, and especially water-filled flexible tubes. Such structures are commonly known as breakwater structures. The invention is directed towards a connection structure to connect two or more flexible tubes.

Background Art

[0002] It is known from GB1163173 a breakwater structure comprising flexible water-filled tubes that are partially filled with water and partially filled with compressed air, so that the tube floats with not more than 1/10<th >of its diameter above the sea surface. The tubes are made from rubber or synthetic plastics. The tubes are moored to the seabed. A netting surrounds the tube and the netting is attached to the mooring.

[0003] The tube is sufficiently heavy so that impinging waves will not tend to set it in oscillation. The waves will instead break dissipate their energy, so that on the opposite side of the tube the water will be relatively calm.

[0004] Several tubes can be joined end to end to create, e.g., a circle around the structure to be protected. The netting is used to connect the tubes.

[0005] ES2167198, CN11021306, CN105019399, US20130170909, KR100187429 and JP2012158934 show other types of floating wave protection or breakwater structures.

[0006] A challenge with the flexible tubular structures, such as shown in GB1163173, is to connect the individual tubes into a sufficiently long breakwater structure. If each tube is made very long, it will have a tendency to twist and deform. Air in the tube may collect at a small portion of the tube, such as at one end and cause the remaining portion of the tube to sink to low in the water. Moreover, a damage to the tube, causing a leak, will remove a large portion of the breakwater structure and allow potentially hazardous waves to enter. Consequently, the structure should be divided into shorter tubes.

[0007] However, a continuous tube also has advantages as the dampening of the wave motion will increase when the whole breakwater can move as one unit. The mooring will also be simpler, as the mooring lines can be connected where the need for mooring is greatest, without taking individual elements into account.

[0008] The connection of the tubes has to be both durable and flexible. A satisfying connection has not been described hitherto in the prior art.

Summary of invention

[0009] The challenge of providing a sufficiently strong and flexible connection between breakwater element has been met by the connection system and method defined in the enclosed independent claims.

Brief description of drawings

[0010] The invention will now be described in further detail, referring to the enclosed drawings, showing an exemplary embodiment, in which:

Figure 1 shows two floating breakwater elements to be connected,

Figure 2 shows a detail of the adjoining ends of the two elements before connection,

Figure 3 shows in a partial cross section the two ends connected to one another by the connection system of the present invention,

Figure 4 shows an isometric view of the connected ends, and

Figure 5 shows the connection system in see-through view

.

Detailed description of the invention

[0011] Figure 1 shows two breakwater elements 1, 2 according to the invention. The two elements are tubular and flexible. They will be partially filled with a fluid, such as water and partially with a gas, such as air. Other means of buoyancy, such as foam or small balls, may however also be feasible. The water may conveniently be freshwater. The elements are conveniently made of rubber or some form of plastics, such as polyethylene (PE), polyvinyl chloride (PVC) or polyurethane (PU). The plastic material may be reinforced with fibres, such as glass fibre, carbon fibres and textile fibres.

[0012] The adjoining ends of the two tubes 1, 2 are shaped differently and complimentary. The first tube 1 is therefore denoted a female tube 1 and the second tube 2 is denoted a male tube 2.

[0013] It should be understood that the opposite ends of the tubes 1, 2 will also have similar elements for coupling with further adjoining tubes.

[0014] The female tube 1 has a conical skirt 3 that extends beyond the tube proper, i.e., the water- and air-filled compartment. The conicity is very small, so it is not readily visible in figure 1. The male tube 2 has no such skirt but is equipped with a plurality of cords 4 that are arranged in a ring on the outside of the tube close to the end.

[0015] The female tube has a plurality of openings 5 close to where the skirt 3 is attached to the tube 1. The number of openings 5 and their mutual distance correspond to the cords 4.

[0016] Close to the openings 5, on the outside of the tube 1, the female tube 1 has a similar plurality of fixation elements 6. These are firmly attached to the tube 1, such as by adhesive, welding or sewing. The fixation elements 6 will be explained further below.

[0017] Figure 2 shows a more detailed view of the adjoining ends of the tubes 1, 2 in disconnected state. In this state the male tube 2 will preferably be in a limp state, i.e., it will only be partially filled with water and air. This means that the tube can be easily compressed by hand.

[0018] The cords 4, which may be lengths of ropes, ribbons, bands or similar, may be wound or curled up in an orderly fashion to avoid tangles. The cords may be bands equipped with hooks and loops to enable easy fastening of the cord either to itself or to the fixation element 6.

[0019] In a preferred embodiment, the fixation elements 6 are eyelets that the cords are fed through.

[0020] A convenient procedure for connecting the two tubes will now be explained.

[0021] When the two tubes 1, 2 have been brought into a short distance from one another, as shown in figure 2, the cords, such as bands with hooks and/or loops, are released and fed into the conical skirt 3, one through each of the holes 5 and through the eyelets 6. To facilitate this, a lead string (not shown) may first be fed through the hole 5 from the outside and out of the open end of the skirt 3. This lead string may already be in place before the female tube 1 is launched, such as during fabrication. There will be one lead string for each of the holes 5. During the connection procedure the lead strings are attached to the outer end of each cord 4. If the lead strings are equipped with hooks and/or loops, these can be used for attachment.

[0022] Then the lead strings are pulled back through the holes 5, and conveniently also through the eyelets 6, pulling the cords 4 along.

[0023] The cords are pulled through the holes 5 and eyelets 6 until the end of the male tube 2 is fully within the conical skirt 3. As the outer diameter of the skirt 3 is smaller than the diameter of the male tube 2, the male tube 2 end may be squeezed to reduce the diameter at the end of the tube 2 to facilitate the entering of the male tube 2 end into the skirt 3. Alternatively, the male tube 2 may be partially deflated when it is inserted into the skirt 3.

[0024] When the tube 2 end is fully within the conical skirt 3, the cords are attached to the eyelets 6. This can be done by folding the cord 4 over itself as shown in figures 5 and 6. The corresponding hooks and loops on the cord 4 will attach to one another forming a tight grip.

[0025] Then the male tube 2 may be inflated by gas, such as air until a certain pressure has been reached. This will cause the male tube 2 to press against the inside of the skirt 3, as shown in figure 4. The friction between the male tube 2 and the skirt 6 created by this, will hold the male tube 2 firmly attached to the female tube 1, and the two tubes will move as one continuous tube in the water. The grip of the conical skirt 3 on the end of the male tube 2 will be firm enough to ensure that the two tubes stay together even in rough water.

[0026] Figures 3, 4 and 5 show in different views the two tube 1, 2 ends connected.

[0027] It is also possible to fasten the cords further from the end of the male tube 2 and let them extend along the outside of the skirt 3 to the eyelets 6. This removes the need for holes 5 in the skirt.

[0028] It is also possible, although more cumbersome, to insert the male tube 2 into the skirt 3 and push the male tube 2 end into the skirt without the assistance of cords 4. Cords, bands, ribbons or other attachments means can be attached between the two tubes 1, 2 after the male tube 2 end has been fully inserted into the skirt 3.

[0029] Using the connection structure of the invention any length of breakwater can be made. Although the breakwater structure will act as a single continuous structure, the individual tubes will each form a separate chamber. This means that water or air cannot move between the tubes, and the individual tubes can be adjusted according to needs by filling them with different amounts of water. Each tube may also be divided into a plurality of chambers by partition walls.

[0030] Mooring lines can be attached to the breakwater at any desired place without having to pay attention to where the different tubes start and end.

[0031] If one tube is damaged, the remaining breakwater will still fulfil its function. Even if it has been deflated, the cords will in most cases have sufficient strength to keep the tubes together. The damaged section can easily be replaced by, if necessary, by deflating the damaged tube and/or neighbouring tubes, detaching the cords and pulling the tubes apart.

[0032] The cords have a design strength that is lower than the fabric of the tubes themselves. Hence, if the tubes are subjected to sever forces, the cords will break before the fabric of the tubes. In that case, two tubes will be pulled apart. This will reduce the forces on the remaining breakwater. The breakwater structure will still function at least partially to dampen waves even if two or more tubes have been pulled apart.

[0033] If the connection between two tubes has been broken, it will be fairly easy to merely replace the broken cords, deflate the male tube 2 somewhat and reattach it with the female tube, whereafter the male tube 2 is again pressurized.

[0034] Both ends of the same tube may be identically formed as male or female, so that every second tube in the breakwater will be either male or female, or the same tube may be a formed with a male interface at one end and a female interface at the opposite end.

[0035] The tubes have preferably a circular cross-section, but they may also have other shapes, such as square.

Claims

1. A connection structure connecting two elements (1, 2) of a floating breakwater structure, wherein a first of said elements (1) has a skirt (3) attached to one end thereof, and a second (2) of said elements has an end formed to be inserted into an open end of said skirt (3) and held in place within said skirt (3) by friction.

2. The connection structure of claim 1, wherein said skirt (3) is conical with the smallest cross-section near or at the open end.

3. The connection structure of claim 1 or 2, wherein said second element (2) has a plurality of cords (4), such as ropes, ribbons or bands attached thereto, and that said first element (1) has a plurality of fixation elements (6) adapted to connect with a respective one of said cords (4).

4. The connection structure of claim 3, wherein said first element (1) has a plurality of openings (5) at or near the widest diameter of said skirt (3), through which said cords extend from the inside to the outside of said skirt (3).

5. The connection structure of claim 3, wherein said cords (4) extend on the outside of said skirt (3) to said fixation elements (6).

6. The connection structure of claim 3 or 4, wherein an outer end of each said cord (4) is attached to a lead string.

7. The connection structure of any of the claims 3-6 , wherein said cord (4) is a band with hooks and loops capable of attaching to itself after having been folded through said fixation element (6).

8. The connection structure of any of the preceding claims, wherein said first and second elements (1, 2) are tubes having at least one chamber to be filled partially with water and partially with pressurized gas, such as air.

9. A method of connecting two elements (1, 2) of a floating breakwater structure, comprising:

a. arranging a respective end of said elements facing one another,

b. feeding a plurality of cords attached to a second of said two elements through a respective opening (5) in a skirt (3) of a first one of said elements (1),

c. pulling said end of said second element (2) into said skirt (3) by said cords (4),

d. attaching said cords (4) to a respective fixation element (6) on said first element (1),

e. inflating said second element (2) until it presses firmly against the inside of said skirt (3).

10. The method of claim 9, wherein said skirt (3) is conical with a narrowest diameter at or near an open end thereof.