GB2117326A - Oil containment boom - Google Patents

Abstract

A boom (1) having at least one partially enclosed chamber (2C) defined by walls of a depending skirt (2) and/or pockets (6) having an opening (5, 7) or openings in a normally upper region and through which opening(s) water may enter said chamber (2C) and/or pockets (6) in the normal position of use of the boom so as to oppose upward displacements of the boom (1). The pockets may alternate on either skirt side. The skirt bottom has a tension wire or ballast. <IMAGE>

Description

SPECIFICATION Improved oil containment boom The present invention relates to an improved oil containment boom for use in containing oil floating on a water surface although the boom is not restricted to such use and may be used for other purposes.

It is known to provide an oil containment boom made of flexible material comprising an elongate inflatable chamber having a skirt depending therefrom with the normally lowermost end of said skirt containing means for retaining such disposed in the lowermost position i.e. ballast means or more particularly a tension wire. Use of a tension wire is known and the present invention is particularly concerned with oil containment utilising tension wires in the lower region of the skirt.

It has been found that with booms having high free-board and having tension wires, in adverse weather conditions they suffer from what is termed "kiting" wherein the booms are lifted out of the water by the waves and wind action. In another situation it is found that the force of the waves is such as to lift the boom above the wave troughs creating the so-called "bridging" effect which undesirably permits oil to pass under the boom in the trough regions. Use of ballast weights in the depending skirt are known although such are expensive to use and make the boom particuiarly heavy and difficult to handle on land and, furthermore, in certain arrangements preclude the rolling of the boom on to a drum for storage purposes.An oil boom is also known wherein two elongate tubes are provided one above the other with the other being inflated from one end with air, and the other being inflated from one end by means of pressurised water.

It is an object of the present invention to provide an oil containment boom with means for inhibiting upward movement from its normal position of use in water.

It is also an object of the present invention to provide means for increasing the stability of any buoyant body e.g. an inflatable life-raft.

In its broadest aspect the present invention comprises a bouyant body having at least one partially enclosed chamber and/or pocket having an opening or openings in a normally upper region and through which opening(s) water may enter said chamber and/or pocket in the normal position of use of the boom so as to oppose upward displacements of the buoyant body. Preferably, the water receiving chamber(s) and/or pocket(s) is made of flexible sheet material so that such may be readily stored when not in use and so that the defining walls of such chamber will readily separate or the mouth of the pocket open-out and permit flow of water thereinto from the water in which the boom is located.

More specifically according to the present invention an improved oil containment boom comprises a bouyant member having a sheet of material or a "skirt" located thereunder in its normal position of use with said skirt having ballast means or a tension wire acting to maintain the skirt beneath the buoyant member and to provide stability for the boom, at least one water receiving chamber and/or pocket disposed beneath said buoyant member in the normal position of use of the boom and having an opening or openings in an upper region of the chamber and/or pocket for the inflow of water from the water in which the boom is located with walls defining said chamber and/or pocket being of flexible material and adapted to move apart so as to create a water receiving space for the water Whilst many different types of floating oil booms (such as ones with solid or inflatable buoyancy and weight or tension wires) may incorporate the present invention, the following description will be restricted, for clarity and by way of example, by inflatable oil booms having a depending skirt and tension wire therein.

In one embodiment of the invention, the buoyant member is an elongate inflatable tube connected to a skirt containing a tension wire by flexible sheet material (which may in fact form part of the skirt) with said flexible sheet material extending from opposite sides of a lower region of the inflatable tube and merging at the top of the skirt region (and may possibly form a continuation of the skirt) so that said flexible material defines a space or chamber beneath the inflatable member.

A plurality of filling/vent apertures are provided in said sheet material in an upper region of the thus formed chamber for the passage of water in filling or emptying the thus formed chamber. The holes are provided on one side only of the device so as to prevent the flow of oil through the boom. This arrangement has the particular advantage of providing an improved connection of the skirt material. with the inflatable portion since the bonding is inclined to the inflatable surface so as to be subject to "sheer" forces rather than to the disadvantageous "peel" forces which exist where the boom material joins tangentially to the inflatable tube and is subject to a downward force.

In an alternative embodiment, which might possibly be combined with the previously described embodiment, the oil boom comprises an elongate inflatable tubular member having a skirt of sheet material depending therefrom and being provided with a tension wire in the lower region, characterised by the feature that on one or both sides of the skirt, sheet material secured to the skirt defines an aiongate chamber and pocket open at its upper end with said sheet material displaceable toward and away from said skirt member with flexible portions at the ends and/or intermediate regions to restrict the degree of displacement of said wall-defining sheet material from the skirt, said opening being provided for the inflow and outflow of water.The wall or walls may be of such material and/or stiffened or reinforced so as to normally move away from said skirt member to provide the opening for the inflow of water. In use, the boom is located in water and during insertion in the water the sheet material defining a wall of the pocket is urged by the water pressure towards the surface of the skirt although, once immersed in water, the water flows into the space provided between the wall and the skirt for each pocket and the stiffeners and/or natural resilience of the material causes the wall to move away from the skirt and water may then flow into the space and thus act as ballast to oppose the upward movement of the boom.In other words, the chamber and/or pocket acts to prevent the boom from rising above the water surface -- thus avoiding the so-called "kiting" effect or the "bridging" effect.

In a further embodiment according to the invention, which is somewhat similar to the previously described embodiment, rather than provide a continuous channel or pocket on one or both sides of the depending skirt member, a plurality of pockets are provided and adapted by being of such material and/or having stiffening or reinforcement, so as to permit the pockets to "open" once immersed in water so that said pockets when in the water inhibit the upward movement of the oil boom. In this arrangement the pockets may be located on one or both sides and may be located alternately on either side.

It will be appreciated that the improved oil boom according to the present invention provides stability in an economic manner so as to act to maintain the boom in the water and in a manner which operates automatically without the requirement of any additional water pumping means and, furthermore, provides an oil boom which in its inoperative state is iightweight and readily storable, e.g. by winding on to a wheel or the like.

The invention will be described further, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a schematic section illustrating an inflatable oil boom with skirt and tension-wire and incorporating flexible wall portions defining a water-receiving chamber; Fig. 2 is a schematic perspective sectional iliustration of an inflatable oil boom with skirt and tension-wire and incorporating two embodiments of the present invention, namely a water receiving chamber beneath the inflatable buoyant portion as shown in Fig. 1 and water receiving pockets on the depending skirt; Fig. 3 is a schematic side elevation of a boom having pockets similar to those of Fig. 1 and wherein the pockets are located on alternate sides of the boom; and Figs. 4, 4A, 4B and 4C are schematic sections through an oil boom wherein a water-receiving pocket is provided on both sides of the depending skirt of an inflatable oil boom with traction wire, and the views show, respectively, the positions immediately prior to insertion, during insertion, the normal fiotation position and when being removed vertically from the water against the action of the water in the pockets.

In Fig. 1 a section through an inflatable oil boom is illustrated comprising an elongate inflatable tubular member 1 of flexible material, e.g. PVC, having a skirt 2 also of flexible material, such as PVC, depending therefrom, via flexible portions 2A, 2B, bonded to the inflatable tubular member 1 on opposite lower regions thereof to form water-receiving space 2C. The skirt 2 has a fold 2D in the lower region containing a tension wire 3 although solid ballast members may be provided as an alternative or in addition. It will be noted that vent holes 4 are provided on one side only of the fold 2D for the tension wire 3 so as to permit escape of any air which may be trapped in the thus formed pocket and to ensure suitable disposition of this portion of the skirt in the water.

The portion 2B has apertures 5 extending along the length of the boom for the inflow and outflow of water into the water receiving chamber (water ballast) defined between the walls 2A, 2B and the lower portion of the inflatable tubular member 1.

The space 2C is caused to open-out by the action of the tension wire 3 on skirt 2.

Fig. 2 is a schematic perspective view of a section of an oil boom similar to that of Fig. 1 but wherein there is additionally provided a plurality of water pockets 7 (only one of which is shown) along the skirt 2. A plurality of pockets 6 may be provided on one side of skirt 2 or the pockets may be alternately disposed on either side of the skirt.

The wall 7 of each pocket 6 is of resilient material so as to normally open-out in the position of use and may be provided with reinforcements 7A, if desired. It will be appreciated that the chamber 2C or pockets 6 of the device on location of the boom in its position of use is caused to open out to provide a water receiving space and water flow therein from surrounding water 8 so as to form a "ballast" region.

Claims (1)

1. A buoyant body having at least one partially enclosed chamber and/or pocket having an opening or openings in a normally upper region and through which opening(s) water may enter said chamber and/or pocket in the normal position of use of the boom so as to oppose upward displacements of the buoyant body.

2. A buoyant body as claimed in claim 1, in which the water receiving chamber(s) and/or pocket(s) is made of flexible sheet material so that such may be readily stored when not in use and so that the defining walls of such chamber will readily separate or the mouth of the pocket openout and permit flow of water thereinto from water in which the boom is located.

3. A buoyant body in the form of an oil boom as claimed in claim 1 or2 comprising a buoyant member having a sheet of material of a "skirt" located thereunder in its normal position of use with said skirt having ballast means or a tension wire acting to maintain the skirt beneath the buoyant member and to provide stability for the boom, at least one water receiving chamber and/or pocket disposed beneath said buoyant member in the normal position of use of the boom and having an opening or openings in an upper region of the chamber and/or pocket for the inflow of water from the water in which the boom is located, with walls defining said chamber and/or pocket being of flexible material and adapted to move apart so as to create a water receiving space for the water.

4. A buoyant body as claimed in claim 3, in which the buoyant member is an inflatable oil boom having a depending skirt with tension wire therein.

5. A buoyant body as claimed in claim 3 or 4 in which the buoyant member is an elongate inflatable tube connected to a skirt containing a tension wire by flexible sheet material, with said flexible sheet material extending from opposite sides of a lower region of the inflatable tube and merging at the top of the skirt region so that said flexible material defines a space or chamber beneath the inflatable member, and in which a plurality of filling/vent apertures are provided in said sheet material in an upper region of the thus formed chamber for the passage of water in filling or emptying the thus formed chamber.

6. A buoyant body as claimed in claim 5, in which the holes are provided in the sheet material on one side only of the chamber so as to prevent the flow of oil through the boom.

7. A buoyant body as claimed in claim 5, in which part of said flexible sheet material is a continuation of the skirt material.

8. A buoyant body as claimed in claim 5, 6 or 7, in which when the inflatable tube is inflated the flexible sheet material joins tangentially with said tube.

9. An oil boom comprising an elongate inflatable tubular member having a skirt of sheet material depending therefrom and being provided with a tension wire in the lower region, characterised by the feature that on one or both sides of the skirt, sheet material secured to the skirt defines an elongate chamber and pocket open at its upper end with said sheet material displaceable toward and away from said skirt member with flexible portions at the ends and/or intermediate regions to restrict the degree of displacement of said wall-defining sheet material from the skirt, said opening being provided for the inflow and outflow of water.

10. An oil boom as claimed in claim 9, in which the wall or walls may be of such material and/or stiffened or reinforced so as to normally move away from said skirt member to provide the opening for the inflow of water.

1 An oil boom as claimed in claim 9 or 10, in which instead of an elongate continuous channel or pocket a plurality of pockets are provided on one or both sides of the depending skirt member and adapted by being of such material and/or having stiffening or reinforcement, so as to permit the pockets to "open" once immersed in water so that said pockets when in the water inhibit the upward movement of the oil boom.

1 2. An oil boom as claimed in claim 11, in which the pockets are located on one or both sides.

13. An oil boom as claimed in claim 12 in which the pockets are located alternately on both sides.

14. An oil boom substantially as herein described with reference to and as illustrated in the accompanying drawings.