GB2275893A - Oil containment boom. - Google Patents

Abstract

A section of oil containment boom 1 comprises a buoyancy tube 2 with a depending wall 3 forming a skirt formed with a pocket 4 in which ballast means 5 is contained. An inflation duct 6 can inflate the tube 2 through valves 17. A membrane 7 within the buoyancy tube 2 separates the interior of the buoyancy tube into several separate compartments. The membrane 7 is secured to the buoyancy tube 2 at longitudinal positions 9 and 10 and in addition is secured to the inner peripheral wall of the buoyancy tube 2 at positions 11 for half of the circumference of the buoyancy tube 2 ie the joint position 9 to the joint position 10 around the sidewall 2a alternately on one side and the other side of the buoyancy tube 2. <IMAGE>

Description

OIL CONTAINMENT BOOM The invention relates to an oil containment boom.

It is important that an oil containment boom which is deployed to contain oil spilt onto water, should reliably provide a containment barrier. Oil containment booms can be divided up into a plurality of sections of perhaps 10 metres length arranged end-to-end along the boom as with the sections separate and isolated such that if one section of the boom is damaged. only a small length thereof will deflate.

Deflation of even a small portion however can have serious consequences if such deflation results in the upper edge of the boom falling to a level at or about that of the surface level of the liquid on which it is floating since this can result in leakage of oil which should be contained over the top of the deflated portion of the boom.

According to the invention an oil containment boom comprises a buoyancy tube with a depending wall and ballast means, an inflation duct and a membrane provided within the buoyancy tube to separate the interior of the buoyancy tube into at least two compartments each communicating via a respective non-return inflation valve with the inflation duct, the membrane being so dimensioned and arranged that in the event of a leak developing in the wall of any one of the compartments of the buoyancy tube. the pressure in the other compartment or compartments causes the membrane to move to a configuration at which it conforms to said wall of said one compartment in which a leak has developed thereby to maintain the inflated shape of the buoyancy tube.

Advantageously the inflation duct is provided to have a shape in section of a major segment of a circle and is provided at the upper edge of the buoyancy tube, that is to say diametrically opposite the depending wall. Thus in section the combined buoyancy tube and inflation duct advantageously can have a cottage-loaf shape which can give considerable advantages over a single circular buoyancy tube of the same height since it allows a considerable reduction in the diameter of the buoyancy tube without reducing the overall height of the containment boom.

Thus for the same volume of air a cottage-loaf shape can give 30% greater freeboard compared with a single circular buoyancy tube. By providing a finite setting on the non-return inflation valves between the inflation duct and the compartments of the buoyancy tube, the boom can be deployed very rapidly by supplying air to the inflation duct as it is unreeled so as initially to inflate the inflation duct only or at least mainly. Thus without requiring a high volume air supply the boom can be rapidly deployed and the inflated inflation duct will provide sufficient buoyancy to support the boom in a floating condition until the buoyancy tube inflates.

Advantageously the membrane is secured to the inner wall of the buoyancy tube continuously at the uppermost position of the buoyancy tube, at the lowermost position of the buoyancy tube and, at intervals along the buoyancy tube, continuously between the uppermost position and the lowermost position of the buoyancy tube. Preferably the non-return inflation valves provided between the inflation duct and the buoyancy tube are provided alternately to one side and to the other side of the uppermost position of the buoyancy tube so as to supply the compartments provided alternately on one side and on the other side of the membrane.

A respective deflation valve is preferably provided for each compartment.

The oil containment boom is preferably provided in sections, each section, for example of 10 metres length, having coupling means at its ends whereby it can be coupled to other sections and having connectors and/or valves at the ends of the inflation duct for connection to the inflation ducts of other sections.

The membrane, the buoyancy tube, the inflation duct and the depending wall are preferably formed of a flexible reinforced material.

Such a material could for example be a polyurethane-nylon-polyurethane sandwich, nylon reinforced neoprene or other plastics material such as PVC. The membrane may if preferred be provided without reinforcement.

In one construction a nylon reinforced polyurethane was utilised and radio frequency welding was used to secure the components of the oil containment boom together. The sheet materials to be secured together were superposed and pressed between a welding bar and a metallic bed plate with application of radio frequency current to secure the sheet materials together.

Other methods of construction such as sewing or cold gluing are applicable according to the materials used.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a sectional view, taken on line II-II of Figure 2, through an oil containment boom according to the invention; Figure 2 is a partial plan view corresponding to Figure; and Figure 3 is a side elevation corresponding to Figures 1 and 2.

Referring to the drawings, an oil containment boom 1, which may for example be 10 metres in length, comprises a buoyancy tube 2 with a depending wall 3 forming a skirt formed with a pocket 4 in which ballast means such as a chain 5 is contained, an inflation duct 6 and a membrane 7 within the buoyancy tube 2 to separate the interior of the buoyancy tube into several compartments. At each end of the boom 1 a rigid vertical bar connector 8 is provided whereby the boom can be coupled to another boom of similar configuration.

The e buoyancy tube 2 is advantageously formed from two strips of material welded together along the length of the boom preferably at diametrically opposite positions, as shown at an upper joint position 9 and a lower joint position 10 and forming side walls 2ss, 2h of the buoyancy tube 2. Alternatively the buoyancy tube 2 and the depending wall 3 can be formed from a single strip of material. The membrane 7 is also secured to the buoyancy tube 2 at the longitudinal joint positions 9 and 10 and in addition is secured to the inner peripheral wall of the buoyancy tube 2 at longitudinally spaced joint positions 11 and 12.The joint position 11 is shown in Figure 1 as well as in Figure 2 and from Figure 1 it can be seen that the joint position 11 extends for half of the circumference of the buoyancy tube 2 from the joint position 9 to the joint position 10 around the side wall 2a.

Sufficient slack is provided in the membrane 7 such that upon a differential pressure arising on the opposite sides thereof, the membrane 7 can move to lie against the side wall 2 or 2b of the buoyancy tube 2 at which the lower of the two pressures arises.

Thus the membrane 7 divides the interior of the boom 1 into several compartments, for example five separate compartments, at least parts of four of which compartments A, B, C, D are shown in Figure 2 which shows only just over half of the length of the boom 1. Each compartment has a respective length of either the side wall 2a or the side wall 2k of the buoyancy chamber 2 and if that respective length of the side wall is punctured, for example by being damaged by impact with a boat, then instead of the respective compartment deflating and that portion of the boom collapsing, the adjacent portion of the membrane 7 is moved over, by the pressure existing in the other compartments, to cause that portion of the membrane 7 to line the damaged portion of the side wall 2a or 2k of the buoyancy chamber 2 to maintain the configuration of the boom erect and inflated.All the compartments along one side of the boom could be punctured without affecting the inflated shape of the boom and even if two adjacent overlapping compartments or opposite sides of the boom were punctured, an unlikely occurrence, only half a compartment length would lose buoyancy.

The inflation duct 6 comprises a strip of material secured at positions 13 and 14 to the buoyancy tube 2 and having flaps 15 and 16 which can provide a useful wave attenuation function. The inflation duct 6 is connected by non-return inflation valves 17 to the individual compartments A to D and at each of its ends is provided with a coupling 18, Figure 3, whereby hoses can be connected to adjacent boom sections, the couplings 18 including valves, or alternatively the couplings 18 being replaced by a sleeve which can be extended for coupling to a sleeve of an adjacent boom, the sleeve preferably including a valve.

Advantageously in use the inflation duct 6 is maintained inflated thereby to increase the height of the upper surface of the boom above the surface of the water in which it is floating to provide more effective containment of spilled oil. Each of the compartments is provided with a manually operable deflation valve 19 which is advantageously so dimensioned and located that if removed it can provide access to the non-return valve 17 of the same compartment to allow servicing thereof.

Even if the buoyancy of the buoyancy tube 3 was completely destroyed the boom will retain the buoyancy of the inflation duct 6 due to the finite setting of the non-return valves 17.

Figure 3 shows that the boom 1 has constant draught. At the lower end this is provided by continuing one wall 4o of the pocket 4 at end positions at which the other wall is cut away to allow the chain 5 to be shackled to the bar connector 8, the continuing wall 4a being looped around a clamp plate 8a of the connector 8 and clamped between the clamp plate 8a and the connector from the other side. Apertures 20 to release air trapped in the pocket 4 are provided only in said other wall of the pocket 4.At the upper end the top edge of the connector is provided level with the top edge of the inflation duct 6 when inflated and to permit this the middle upper part of the end of the material forming the inflation duct is folded inwardly to form a pleat as shown at 6a in Figure 3 with two edges 6b shown also in Figure 2 to give the boom 1 constant freeboard. This has the advantage of reducing the height of the connector bar 8 thereby reducing weight at a position of low buoyancy, lowering the centre of gravity of the connector bar 8 and reducing windage thereon. The upper edge of the buoyancy tube 2 extends upwardly at the end position, due to the flattening thereof, as shown at 2: in Figure 3 towards the pleat 6a. The wave attenuation flaps are preferably cut off short of the connector 8 at positions 15 and 16 and reinforcing panels 21 and 22 are provided, on side portions of the buoyancy tube 2 and the depending wall 3 respectively, to distribute mooring and towing loads.

Claims (10)

1. An oil containment boom comprises a buoyancy tube with a depending wall and ballast means, an inflation duct and a membrane provided within the buoyancy tube to separate the interior of the buoyancy tube into a plurality of compartments each communicating via a respective non-return inflation valve with the inflation duct, the membrane being secured to the inner wall of the buoyancy tube continuously at the uppermost position of the buoyancy tube, at the lowermost position of the buoyancy tube and, at intervals along the buoyancy tube, continuously between the uppermost position and the lowermost position of the buoyancy tube, and the membrane being so dimensioned and arranged that in the event of a leak developing in the wall of any one of the compartments of the buoyancy tube, the pressure in the other compartments causes the membrane to move to a configuration at which it conforms to said wall of said one compartment in which a leak has developed thereby to maintain the inflated shape of the buoyancy tube.

2. An oil containment boom according to claim 1. in which the setting on the non-return inflation valves between the inflation duct and the compartments of the buoyancy tube is such that supplying air to the inflation duct as it is unreeled initially inflates the inflation duct only or at least mainly so that the boom can be rapidly deployed with the inflated inflation duct providing sufficient buoyancy to support the boom in a floating condition until the buoyancy tube is inflated.

3. An oil containment boom according to claim 1 or claim 2, in which the inflation duct has a shape in section of a major segment of a circle and is provided at the upper edge of the buoyancy tube, that is to say diametrically opposite the depending wall.

4. An oil containment boom according to any one of claims 1 to claim 3, in which the securement of the membrane at intervals between the uppermost position and the lowermost position of the buoyancy tube is effected alternatively to one side and to the other side of the buoyancy tube.

5. An oil containment boom according to claim 4, in which the non-return inflation valves provided between the inflation duct and the buoyancy tube are provided alternately to one side and to the other side of the uppermost position of the buoyancy tube so as to supply the compartments provided alternately on one side and on the other side of the membrane.

6. An oil containment boom according to any one of claims 1 to 5, in which a respective deflation valve is provided for each compartment.

7. An oil containment boom according to any one of claims 1 to 6, in which the oil containment boom is provided in sections, each section having coupling means at its ends whereby it can be coupled to other sections and having connectors and/or valves at the ends of the inflation duct for connection to the inflation ducts of other sections.

8. An oil containment boom according to claim 7, having constant freeboard by forming a pleat in the upper wall of the inflation duct at each end thereof adjacent a vertical bar forming the coupling means at the respective end of the boom section.

9. An oil containment boom according to claim 6 or claim 7, having constant draught by providing the depending wall to extend, for the full depth thereof, up to the coupling means at its ends.

10. An oil containment boom substantially as hereinbefore described and illustrated with reference to the accompanying drawings.