GB2140401A

GB2140401A - Method and apparatus for preventing or minimizing pollution of a shore by oil

Info

Publication number: GB2140401A
Application number: GB08310355A
Authority: GB
Inventors: Peter Townsend
Original assignee: Hoyle Marine Ltd
Current assignee: Hoyle Marine Ltd
Priority date: 1983-04-16
Filing date: 1983-04-16
Publication date: 1984-11-28
Also published as: GB8310355D0

Abstract

Pollution by oil of beaches, coastlines or shore lines is prevented or minimized by locating netting or net (6) of fine mesh, which is such as to retain oil thereon, over the surface of the area of shore to be protected and securing such netting or net in position, and subsequently removing said netting or net from the surface of the shore together with any oil retained thereon for subsequent removal therefrom. The apparatus for preventing or minimizing pollution of a shore by oil comprising a buoyant oil boom (1) having at least one net (6) secured thereto and depending therefrom along its length and with said net being of such mesh size and/or construction as to retain oil thereon. <IMAGE>

Description

SPECIFICATION Method and apparatus for preventing or minimizing pollution of a shore by oil The present invention relates to a method and apparatus for protecting beaches and rocky coastlines in mainly marine situations from pollution by oil and especially by heavy crude oil.

Hithereto to protect beaches or rocky coastlines from oil pollution floating booms have been provided offshore to prevent oil from reaching the coastline although with certain heavy crude oil which floats beneath the surface of the water and may pass under a boom or in rough weather conditions, the oil will not be contained by the boom and will reach the shoreline and will then have to be removed mechanically by removing the polluted sand area or possibly by chemical treatment. Both these cleaning operations are expensive and damaging to the environment.

It has also been proposed to utilize a buoyant oil boom which has an upper air-filled compartment and a lower compartment filled with water and which may, when not floating, rest on a beach or other surface threatened with pollution by oil. It has been found in certain circumstances, however, that oil may pass under such a boom or, when the tide has ebbed, oil which may have been retained by such boom (or any other oil boom) is deposited on the beach adjacent the boom and has then to be removed mechanically.

It is an object of the invention to provide a method and device for removing oil from beaches and coastlines or preventing contamination by oil and/or a method and apparatus for preventing or minimizing pollution of beaches and rocky coastlines.

According to the present invention a method of preventing or minimizing pollution by oil of beaches, coastlines or like shore lines, comprises locating netting or net of fine mesh which is such as to retain oil thereon over the surface of the area of shore to be protected and securing such netting or net in position, and subsequently removing said netting or net from the surface of the shore together with any oil retained thereon for subsequent removai therefrom.

The net is mainly intended for collecting crude oil thereon which is thick and very viscous. The net will preferably be of manmade fibre, such as a combination of very fine monofilament and multifilament, and be of such construction and/or mesh size as to retain oil thereon.

The net may be secured to the shore as desired, e.g. with stakes on a sandy or pebble beach or weights on a rocky shore.

The net with any oil thereon may be rolled up and the oil removed by any suitable process such as mechanically or by steam cleaning or any other suitable method.

Also according to the present invention an apparatus for preventing or minimizing pollution of a shore by oil comprises a buoyant oil boom having at least one net secured thereto and depending therefrom along its length and with said net being of such mesh size and/or construction as to retain oil thereon.

The oil boom will preferably be of the type which has an inflatable upper air chamber and a lower chamber inflatable with water and the boom or barrier being such that when inflated the boom will float with the chamber inflated with water being below the level of the water in which the boom floats and such that when inflated and resting on a beach, the water chamber of the boom rests on the beach with the air chamber thereabove so as to provide a barrier to prevent passage of oil.

Here also, the net will preferably be made of man-made fibre and be such as to retain oil thereon. Two lengths of net may be provided and securable to extend either side of the boom if resting on a shore, if desired.

The apparatus may be utilized in sea areas where it does not come to rest on the shore surface at low water in which case the net will depend from the boom and will preferably be weighted at its lower end. However, the apparatus is primarily intended to be used to protect regions of a beach between high and low water and, preferably, whenever the boom rests on the shore surface for at least a part of the time. The net may freely depend and be weighted at its lower end, if desired.

Alternatively, the net may be secured to the shore at its edge remote from the main body of the boom to prevent oil passing although will have to have a mesh size which is not too small as to undesirably resist the flow of water.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of an oil boom/barrier which is such as may sit on a shore and having a net depending therefrom; and Figure 2 is a diagrammatic illustration of an oil boom according to Fig. 1 moored in position on a steeply shelving beach at high water.

In Fig. 1 a portion of an inflatable oil boom 1 is schematically illustrated partly in end section and comprises an upper tube 2 inflatable with air and a lower tube 3 inflatable with water and having a restricting flexible strap 4 of a length less than the diameter of tube 3 to provide for stability of the boom when resting on a shore and prevent rolling of the tube 3 which might lead to the boom toppling over.

Instead of strip 4 an apertured and flexible restricting or stabilizing member may extend along the length of and across tube 3 and of less diameter thereof.

A flap 5 is provided along the bottom of tube 3 and has a fine mesh net 6 of manmade fibre secured thereto and depending therefrom. The net 6 may be secured by known securing or bonding techniques e.g. by using plastic cable ties (not shown) extending through apertures (not shown) along the length of flap 5. The mesh size of net 6 is such (e.g. 2 cm.) as to retain oil and especially crude oil whilst not being too fine as to undesirably restrict the flow of water therethrough. Instead of being secured to a flap 5 the net 6 may be secured to another region of the boom e.g. to the side thereof such as to tube 2 or 3 or to the top of the tube 2 as desired and extend beneath the tube 3 to a desired amount e.g. 100 cm. or 5 metres or more depending upon the type of crude oil involved and the depth at which it may be floating.

It will be appreciated that the lower edge of the net may be secured along its length to a beach at a desired location to take into account the likely tidal rise and fall so as to protect the desired area. The ends (not shown) of the boom may be secured in known manner. If desired, a tension wire may be provided along the bottom edge of the net 6.

Other oil booms may be produced having net secured or securable thereto and depending therefrom and where such are to be used away from beaches in deep water, the lower edge of the net may have a tubular pocket formed therein or otherwise receive a cable or wire, chain or other weights for ballast purposes and which may be tensioned, if desired.

For other known booms have an air inflatable or otherwise buoyant upper portion and a skirt dependent therefrom, and which may or may not have a tension wire thereabouts, net may be secured to the bottom of the skirt and tension wire, if provided, e.g. by providing apertures in the skirt along the length thereof above the tension wire, if provided, and by looping securing means such as plastics material cable ties through the apertures and the upper portion of the net and securing such.

It will be appreciated that the method according to the invention may be simply effected by locating and securing sheets of net on a beach although use of the above described boom may accomplish the same effect especially between high and low water lines.

Claims

1. An apparatus for preventing or minimizing pollution of a shore by oil comprising a buoyant oil boom having at least one net secured thereto and depending therefrom along its length and with said net being of such mesh size and/or construction as to retain oil thereon.

2. An apparatus as claimed in claim 1, in which the oil boom has an inflatable upper air chamber and a lower chamber inflatable with water and the boom or barrier is such that when inflated the boom will float with the chamber inflated with water being below the level of the water in which the boom floats and such that when inflated and resting on a beach, the water chamber of the boom rests on the beach with the air chamber thereabove so as to provide a barrier to prevent passage of oil.

3. An apparatus as claimed in claim 1 or 2, in which the net is made of man-made fibre and be such as to retain oil thereon.

4. An apparatus as claimed in any of claims 1 to 3 in which two length of net are provided and securable to extend either side of the boom.

5. An apparatus as claimed in any of claims 1 to 4 in which the net freely depends from the boom and is weighted at its lower end.

6. An apparatus as claimed in any of claims 1 to 5, in which the net has a mesh size which is not too small as to undesirably resist the flow of water.

7. An apparatus constructed and arranged to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.

8. A method of preventing or minimizing pollution by oil of beaches, coastlines or like shore lines, comprising locating netting or net of fine mesh, which is such as to retain oil thereon, over the surface of the area of shore to be protected and securing such netting or net in position, and subsequently removing said netting or net from the surface of the shore together with any oil retained thereon for subsequent removal therefrom.

9. A method as claimed in claim 8 in which the net is of man-made fibre such as a combination of very fine monofilament and multifilament and is such construction and/or mesh size as to retain oil thereon.

10. A method as claimed in claim 8 or 9, in which the net depends from a buoyant oil boom.