WO1991008348A1

WO1991008348A1 - Oil spill area containment system

Info

Publication number: WO1991008348A1
Application number: PCT/GB1990/001831
Authority: WO
Inventors: Chaplin Ching Peng Chang; Ken Tracton
Original assignee: Chaplin Ching Peng Chang; Ken Tracton
Priority date: 1989-11-24
Filing date: 1990-11-26
Publication date: 1991-06-13
Also published as: IE904251A1; AU6881291A; GB8926573D0

Abstract

An elongate, flexible, buoyant barrier (10) for use in containing spillage of oil on a body of water, such as a sea, lake or river. The barrier in use is partially submerged with its length extending horizontally and around an arc. The barrier (10) comprises a first, inflatable compartment (11) and a second compartment (11), for filling with water. The barrier is either (10) endless or has at its ends means (13) either for interconnecting the ends or for connecting the ends to another structure. The amount of water used to flood the second compartment can be controlled to determine the degree of submergence of the barrier.

Description

OIL SPILL AREA CONTAINMENT SYSTEM

The present invention relates to a system, and more particularly a barrier, for containing oil or the like when spilled on a body of water, such as sea, lake or river. In this specification, the word "oil" is to be taken to include related substances.

The problems caused by oil spills are well known, particularly the damage to the environment and possible loss of revenue to the carriers and/or suppliers of the oil. Many oil spills are caused by leakage from sea-going oil tankers, often through rupture of the vessel hull. The spilt oil, having a density less than that of water, will spread across the surface of the body of the water and is a major hazard unless its flow is checked. Methods of dealing with the spilt oil, such as the use of detergent or bacteria to break down the oil, or its collection and separation from the water can only be truly effective if the oil is contained. Accordingly, there is a need for some means for containing the oil spillage.

According to a first aspect of the present invention, there is provided an elongate, flexible, buoyant barrier, for containing, in use, a spillage of oil on a body of water, such as a sea, lake or river, the barrier in use being partially submerged with its length extending horizontally and around an arc, the barrier comprising a first, inflatable compartment and a second compartment, for filling with water; the barrier either being endless or having at its ends means either for interconnecting the ends or for connecting the ends to another structure, such as a ship's hull.

In the event of an oil spill, the barrier is erected by inflating the first, normally an upper, compartment and at least partially filling the second, normally lower, compartment with water, each compartment preferably being a hollow cylinder, and the barrier is deployed around the area of the oil spill. The amount of water used to flood the second compartment can be controlled to determine the degree of submergence of the barrier according to the prevailing conditions.

Along the length of the lowermost compartment, a skirt may be provided to prevent oil escaping underneath the barrier due to motion of the barrier caused by waves. The height of the skirt may be largest towards the points of connection with the ship since pitching and rolling of the ship is likely to result in the greatest movement of the barrier being adjacent the ship.

Preferably, the connection means includes a flat non- inflatable portion at one or both ends of at least one of the compartments. The flat portions may be readily fixed to the ship or to one another and also enable the barrier to be quickly detached from the ship in an emergency by cutting through the flat portions. A quick release mechanism may additionally or alternatively be provided to enable the barrier to be quickly detached from the ship or other structure in an emergency. More preferably, the connection means further includes a first strip and a second strip for clamping the non-inflatable portion between the first and second strips. The first strip or strips may first be fixed to the ship and the flat portion then clamped between the first and second strips. An endless barrier can be erected around an isolated spill.

Preferably, the barrier has a plurality of compartments, say six or seven, each of which may be selectively inflated or filled with water and which may be stacked one on top of the other to form a wall. By this means, in heavy seas, for example, further, lower tubes may be filled with water so as to cause the barrier to sit lower in the water, thereby increasing the stability of the barrier. According to a second aspect of the present invention, a method of deploying an elongate, flexible, buoyant barrier to contain a spillage of oil on a body of water from a ship or other structure, the barrier in use being partially submerged with its length extending horizontally and around an arc, includes the steps of inflating a first compartment of the barrier with a gas; at least partially filling a second compartment of the barrier with water; and fixing the barrier at each of its ends to the ship or other structure with the first compartment uppermost.

An example of the present invention will now be described with reference to the accompanying drawings, in which:-

Figure 1 is a diagrammatic perspective view of a barrier attached to a ship's hull;

Figure 2 is a cross-sectional view of a deployed barrier; Figure 3 is a view showing in greater detail part of the connection means;

Figure 4 is a view from above showing one end of the barrier attached to a ship's hull;

Figure 5 is a diagrammatic perspective view of a valve; and,

Figure 6 is a view of a barrier fitted with a skirt.

In Figure 1, a ship 1 is shown having a rupture 2 through which oil 3 has flowed. A barrier 10 is shown in its operational configuration. The barrier 10 has seven similar, hollow cylindrical compartments 11,11* only five of which are shown above the surface of a body of water 4.

The compartments 11,11* are stacked on top of each other so as to form a wall and are approximately 30cm in diameter when inflated or filled with water. The total length of the barrier is of the order of 90m, but, naturally, the length can be varied according to requirements.

In this example, as shown most clearly in Figure 2, only the two lowermost compartments 11' are filled with water, causing the two lowest compartments 11' to be fully submersed and the next compartment 11 up to be partially submersed. The upper five compartments 11 are inflated with air. Should the prevailing conditions require. further lower compartments 11 may be filled with water so as to cause the barrier 10 to sink further into the water 4 and thus provide further stability against high winds, waves, etc. In this^• particular example, as the ship 1 is not damaged too badly and has therefore remained afloat, the barrier 10 has been attached at its ends 12 (only one of which is shown) to the hull 5 of the ship by connecting means 13. The barrier 10 forms part of a loop around the oil spillage 3, the ship 1 serving to close the loop.

As shown most clearly in Figures 3 and 4 , the connecting means 13 preferably includes detachable metal strip links 14,15.

The strip links 14,15 are paired in equal number to the number of compartments 11,11*. Each of the first strips 14 has a pair of projections 16 and a recess or through-hole 17. Each of the second strips 15 has a pair of recesses 18, which correspond to and receive the projections 16, and a through-hole 19 corresponding to the recess or through-hole 17.

To attach the barrier 10 to the hull 5, the first strips 14 are fixed to the hull 5 by welding, bolting or other similar permanent means. Each compartment 11,11* has a portion 20 which is not inflatable and is thus generally flat. The flat portion 20 of each compartment 11,11* is placed over a respective first strip 14 and the corresponding second strip 15 placed over that and being held initially by the projections 16 being received in the recesses 18. The projections 16 may pierce or merely push against the material of the barrier 10. A small explosive bolt or impact bolt (not shown) is then fixed through the hole 19 into the recess 17 to clamp the flat portion 20 of the compartment 11,11' between the strips 14,15. The bolt may be metal piercing and pass right through the recess or through-hole 17 into the hull 5 thus fixing the pairs of strips 14,15 to the hull 5 and obviating initial fixing of the first strips 14 to the hull 5. If the first strips 14 are welded to the hull 5, welding may be carried out by means of flash welding and, in fact, the first strips 14 may contain an embedded thermite strip (not shown) that can be ignited after placing the strip 14 against the hull 5. Thermite is a mixture of finely divided aluminium and oxides of iron or other metals, which produces a very high temperature (around 3000°C) on combustion, which would weld the metal strips 14 to the hull 5. As an alternative (not shown) to the use of several pairs of strips 14,15 to allow for the curve of the hull, a pair of elongate strips of flexible metal mesh may be used to fix each end of the barrier 10 to the hull 5. The flat portions 20 of the compartments 11,11' would again be clamped between the mesh strips which are then fixed to the hull 5 by bolts or other suitable permanent fixing means. A first mesh strip may or may not be fixed initially to the hull 5 following rupture.

In either case, the barrier 10 is readily removed from the ship 1 should the ship 1 begin to sink by cutting through the flat portions 20. The two ends of the barrier 10 may then be brought together and fixed to one another so as to ensure that the oil that has already flowed out is still contained. To facilitate the interconnection of the two ends of the barrier 10, further pairs of strips 14',15' or metal mesh strips may be fixed to the barrier 10, clamping the flat portions 20 of each end of the barrier therebetween, as shown in figure 4. The further pairs would be placed adjacent the first pairs, but free from attachment to the ship 7. The flat portions 20 should be cut between the two sets of strips so that the released barrier 10 has strips at each end which may then be fixed together by bolting or welding.

Each tubular compartment 11 has a valve 21 having a piston 22 which is biased against a slotted diaphragm member 23 by a coil spring 24. The valves 21 allow filling with air or water of each compartment 11,11'. The barrier 10 preferably has a length to height ratio in excess of substantially 15 to 1 and, in one particular example the length to height ratio is substantially 50 to 1. When not in use, the non-inflated barrier 10 can be folded or stored as a roll which enables the barrier 10 to be deployed very rapidly when needed. Various size barriers can be provided according to the size of ship in use.

Along the length of the lowest compartment 11', a dependent skirt 25 may be provided to prevent oil escaping underneath the barrier 10 due to motion of the barrier 10 caused by waves. The skirt 25 may be flared at its ends so that the height of the skirt is largest towards the connection with the ship, since pitching and rolling of the ship will result in the greatest movement of the barrier 10 being adjacent the ship 1.

In a similar way, the height of the barrier 10 may be increased towards its ends by the provision of further upper compartments 11" which are tapered away from the ends of the barrier.

As an alternative to the example shown in the drawings, where the barrier is at least initially fixed to a ship 1, the barrier 10 can be used alone, in which case the ends 12 may be joined to each other by the connecting means 13. The circular barrier 10 thus formed can be used to contain oil spills that are either remote from a vessel.

The barrier 10 may be erected either by using the vessel's own pumps in order to inflate the upper compartments 11 and to fill the lower compartments 11 with water. Alternatively, if the barrier is remote or if the vessel is without power, the barrier 10 pan be erected by the use of various means including, for example, compressed air (from a compressor or from separate cylinders) , hand pumps, or gas released from a suitable reaction between compounds contained within the barrier 10, the reaction being initiated on deployment of the barrier 10. The barrier 10 should be composed of a material which is both oil and water-resistant, and which is also resistant to sea water.

The barrier can be formed by joining two elongate sheets of an appropriate flexible material together at intervals, so as to form the separate compartments 11. Alternatively, a plurality of pre-formed compartments may be joined together.

Claims

1. An elongate, flexible, buoyant barrier (10) , for containing, in use, a spillage of oil on a body of water, the barrier in use being partially submerged with its length extending horizontally and around an arc, the barrier (10) comprising a first, inflatable compartment (11) and a second compartment (11*), for filling with water; the barrier either (10) being endless or having at its ends means (13) either for interconnecting the ends or for connecting the ends to another structure.

2. A barrier according to claim 1, wherein the connection means (13) includes a flat non-inflatable portion (20) at one or both ends of at least one of the compartments (11,11*).

3. A barrier according to claim 2, wherein the connection means (13) further includes a first strip (14) and a second strip (15) for clamping the non-inflatable portion between the first (14) and second (15) strips.

4. A barrier according to claim 3, wherein a second pair of strips (14,15) is provided proximate the first pair of strips (14,15).

5. A barrier according to any of claims 1 to 4, further comprising a skirt (25) depending from the second compartment (11*) .

6. A barrier according to claim 5, wherein the skirt (25) is flared downwardly at the ends of the barrier.

7. A barrier according to any of claims 1 to 6, wherein at least one of the compartments (11) includes a filling valve (21) .

8. A barrier according to any of claims 1 to 7, comprising at least six substantially identical compartments.

9. A barrier according to any of claims 1 to 8, wherein at least one of the uppermost compartments (11") tapers away from the ends of the barrier so that the barrier has a relatively greater height at its ends.

10. A barrier according to any one of claims 1 to 9, wherein the length to height ratio of the barrier (10) is in excess of substantially 15 to 1.

11. A barrier according to claim 10, wherein the length to height ratio is substantially 50 to 1.

12. A method of deploying an elongate, flexible, buoyant barrier (10) to contain a spillage of oil on a body of water form a ship (l) or other structure, the barrier in use being partially submerged with its length extending horizontally and around an arc, including the steps of inflating a first compartment (11) of the barrier (10) with a gas; at least partially filling a second compartment (11*) of the barrier (10) with water; and fixing the barrier (10) at each of its ends to the ship (1) or other structure.

13. A method according to claim 11, wherein the step of fixing the barrier to the structure includes fixing first strips (14) to the structure and clamping the ends of the barrier (10) between the first strips (14) and respective second strips (15) .