WO1994017251A1

WO1994017251A1 - Device for collecting spillage and leakage, from shipwrecks

Info

Publication number: WO1994017251A1
Application number: PCT/NO1994/000017
Authority: WO
Inventors: Leif Andreassen
Original assignee: Ocean Guard A/S
Priority date: 1993-01-22
Filing date: 1994-01-20
Publication date: 1994-08-04
Also published as: AU6011694A; GB2289854B; NO930214L; NO176813B; NO930214D0; GB2289854A; GB9514711D0; NO176813C

Abstract

Device for collection of spillage and leakage, especially oil, from shipwrecks (11). A hood (13) is adapted to be situated over the wreck and is connected to a riser (18), extending to a level below the sea surface, from where the spillage can be transferred to a collecting tank. In the upper section (19) of the riser (18) is formed a buoyancy body (37), preferably by means of being air filled. Inside the riser (18), from the lower edge of said buoyancy body (37) and down to and including the hood (13), spillage (28) can be collected and/or temporarily stored.

Description

Device for collecting spillage and leakage, from shipwrecks

The present invention concerns a device for collecting spillage and leakage, especially oil, from shipwrecks and other submerged structures or reservoirs, as stated in the introductory part of claim 1. Such a collecting device can be used to collect contaminants emerging from the countless shipwrecks in all waters.

Background

With an increasing pollution and environmental consciousness, efforts to prevent further pollution will increase. This also applies to pollution originating from subsea sources of pollution, e.g. shipwrecks, pipes or other submerged structures or reservoirs, which can be exposed to spillage or leakage.

From Norwegian Patent Application 2929/69 there is known a device where a cover can be suspended over a wreck and connected to a pipe leading up to the sea surface through which the oil can be moved to a container situated on a vessel. This solution has not been practical because, among other things, it has proved to be impossible to manufacture a riser that can withstand the length variations which have to be accomodated because of the wave movement of the vessel.

GB Patent Application 2 063 776 describes a collecting hood anchored to the sea¬ bed, for collecting blowouts. However, this equipment demands immediate drainage of the spillage, which will be a mixture of gas and oil.

Object

The main object of the invention is therefore to provide such a collected device which can guide spillage and leakage from a position at, or close to, the seabed and up to the surface for appropriate collection. It is an object to provide a device that is not sensitive to wave movement. It is particularly an object to provide a device that can be located on a shipwreck or similar, and which can be maintained in a state of readiness for collection of even small spillage over a long period, without continous supervision and drainage. It is imporant that the equipment can remain in the sea, without disturbing ordinary surface traffic, and without being influenced by climatic conditions. The invention

According to the invention, this can be acheived by forming the device as stated in the characterizing part of claim 1.

This solution renders it possible to provide a collection device which can be used in a number of instances, where previously it has been impossible to perform safe collection.

The device according to the basic invention can be improved in different ways as stated in claims 2-9.

The invention will, according to one embodiment, be described in the following with reference to the drawings, in which: -

Fig. 1 is a schematic side view of a device according to present invention, when located over a shipwreck,

Fig. 2 illustrates on a larger scale an alternative embodiment of the top of the riser, and in more detail than in Fig. 1, and Fig. 3 is a side view in more detail of the riser.

In Fig. 1 there is shown a partly submerged shipwreck 11 on seabed 12. Above the shipwreck is located a hood 13 made of a suitable cloth material and of a pyra¬ midal shape and dimensions corresponding to the size of the wreck. The hood 13 is anchored to the seabed with grapnels or heavy weigths 14 and 15 and at its lower edge is provided at intervals with weights 16. The top 17 of the hood is closely connected to a riser 18, also made of cloth material, which extends up through the body of water and to terminate in an upper cylindrical part 19, in this case shaped as a tube, as an extension of the riser 18. The upper part 19 of the riser 18 is provided with a cover or lid 20 which will be described further in connection with Fig. 2. The main function of the cover or lid 20 is to close the riser 18 at its upper end, and serve as a connection organ for draining spillage. In Fig. 1 there is shown a spillage flow 21 rising from a tank in the ship¬ wreck 11 which collects beneath hood 13 and is guided up through the riser 18 towards its upper part 19.

In the upper part 19 of the riser is situated a displaceable piston shaped barrier 22 which is connected to a drainage hose 23 leading to a valve 24 with lid 20. From the lid 20 a line 25 extends up to a buoy 26, having a warning light 27, adapted to float on the sea surface.

This construction permits spillage 21 to be collected in the interior of the riser 18, under the barrier 22, as shown at 28. The riser 18 and its upper part 19 can be dim- ensioned so that the volume 28 corresponds to collection of spillage over a period from a day to some weeks.

In Fig. 2 there is shown a more detailed alternative embodiment of the top of the riser. Instead of a displaceable barrier or piston, is here a diaphragm or a sealing cloth 29 arranged to be tightly connected to the riser 18, and which is connected to drainage hose 23 leading up to the valve 24 (shown schematically). The valve 24 is provided with a connector piece 30 for connection to a drainage pipe (not shown) while the end section is covered with a lid 31. Under the lid 31 is a bushing 32, situated in the covering wall 20, which has a valve 33 and a connector piece 34 for provision of air which can stabilize the upper end of the riser 18 in the water. In Fig. 3 there is shown a more detailed view of the riser 18. The riser 18 is here provided with a fishnet stocking 35 which extends over the entire length and pro¬ vides increased strength to endure tension and internal pressure.

Alternatively, a cloth material can be used in the riser 18, which is correspond- ir reinforced, e.g. with glass fibre. In order to stabilize the riser 18 in the water it zovic . wtih at least one ring shaped floating body or float 36 which in an appropriate manner is anchored to the fishnet stocking 35, e.g. with ties 38.

The ring shaped float 36 can additionally serve as an anchor for a guide wire 39 by means of a guide ring 40 outside the float. The guide wire 39 can extend between a weight at the seabed (not shown) and a buoy (not shown) at the sea surface.

The device is intended for collecting small and large oil leakages from wrecked ships, etc. It is adapted to be situated stationary above the place of interest over a long period of time where it continuously, by means of the hood 13, collects and carries up in the riser 18 oil spillage which can be removed later by drainage hoses connected to connector piece 30. Both pipe and hood are manufactured from a strong antifouling plastic material, which on its outer surface is coated by a layer of net and at all edges is reinforced with two layers of rope having sufficiently strength for connection of weights, lines for grapnels etc. The upper part 19 of the riser 18 is manufactured from fully cast, reinforced plastics which is provided with a lid having the neccessary elements for connection of hoses or pipes for removal of oil, provision of air for positive buoyancy, bushing nipples for different measuring apparatus (not shown), etc. Outside the riser 18 floats 36 are premounted at desired intervals, dependent upon the intended use of the device and the positive buoyancy desired and taking into account flow conditions. A float can also be situated at the passage between the collection hood 13 and the riser 18 in order to reinforce this passage. The hood 13 shown in Fig. 1 can be expanded with connector pieces of desired size, in order to provide a greater collection surface.

At the lower edge of the hood is mounted fastening straps which can be used to fasten weights or for fastening directly to a ship wreck. Such straps can also be used for connection of optional connector pieces.

Installation

The installation of the collection hood 13 can be done after the wreck has been video-taped by a submersible vessel and after the spread of the oil leakage is known.

The entire system is balanced so that the fixed floats and a certain number of weights mounted by fastening straps to the lower edge of the collecting hood 13 or at mounted connector pieces outweigh each other, with a minor overweight of the weights. When the system, by means of a surface vessel, is submerged in the water, the entire sytem will extend to its full extension. The surface vessel can have guide wires fastened as illustrated in Fig. 3. The system will then be guided slowly to¬ wards the wreck. A submersible vessel can be used to fix the premounted straps to the wreck. This can be done at places on board, e.g. to yardarms, capstans, pipes etc. Where such fastening is not possible, the premounted weights and optionally the grapnels 14 and 15 as shown in Fig. 1 can be utilized.

One of the valves of the lid 20 should be open in order to let air in the upper part of the device to be displaced to acheive a negative buoyancy. When the entire construction is on site, the open valve in the top lid 20 is closed, whereupon some air is supplied which will straighten the construction. Finally, the neccessary signal light is located as described above. The construction is now ready for operation and oil leaking out of the wreck will be collected and guided into the riser runing up from the top of the collecting hood 13 to the desired level below the sea surface, e.g. approximately 20 m, so that it is free for traffic above the device. This depth makes possible for diving work to effect fastening of the neccessary pipes for removal of collected oil. The oil will rise up through the riser and collect at the top thereof due to the air pumped in whereupon at intervals it can be removed using drainage pipes (not shown) from a surface vessel.

The riser 18 together with its upper section 19 has three functions. Firstly, it pro¬ vides the riser function for spillage to rise from the hood 13 to a outlet under the surface. Furthermore, it provides space for preliminary collection of spillage, so that it is unneccessary for countinous withdrawal from the surface. Finally, the upper section should provide sufficient buoyancy and weight in order to keep the device in balance in the water. Beyond this, the top of the riser 18 should be provided with different connection equipment, etc. , as stated above. The collection option is a central function for the device according to the inven¬ tion. In the example in Fig. 1, a riser 18 made of a flexible cloth material is used, having an upper rigid section 19 made of reinforced plastics in order to form a collection space, having equal cross section for both parts. The use of a cylindrical, rigid section 19 is neccessary in the case where a piston 22 is used as a barrier be- tween collected spillage and entrapped air (Fig. 1). It is possible to form the tube shaped riser 18 with a smaller diameter than the collection section 19.

In an alternative embodiment (not shown), the collection section can be formed as a flexible, optionally sausage shaped container, having an arbitrary shape and exten¬ sion. Also in this case it is neccesary to provide a controllable buoyancy pocket with air, so that the buoyancy of the container can be controlled.

In such an embodiment, the connection between the collection section and the riser can be releasable so that the collection section can be towed away after becoming fil¬ led and replaced with an empty collection section. The connection between the riser and the collection section can be formed in a fundamentally known manner, with possibilities for diving services. The collection section can be formed as an air mattress, having parallel chambers in carpet shape.

Claims

Claims:

1. Device for the collection of spillage and leakage, especially oil, from shipwrecks (11) and other submerged structures or reservoirs, the device including a hood (13) adapted to be situated over the wreck or other submerged similar object and a riser (18) or a riser hose is connected to the hood, extending to a level below the sea surface and from where the spillage can be transferred to a collecting tank, characterized by a buoyancy body (37) is formed in the upper section (19) of the riser (18), preferably by means of being air filled, and that inside the riser (18), from a lower edge of said buoyancy body (37) and down to and including the hood (13), spillage (28) can be collected and/or temporarily stored.

2. Device according to claim 1, characterized by the upper section (19) of the riser (18) being dimensioned to be terminated approximately 20 m below the surface of the water, or less at smaller depths.

3. Device according to claim 2, characterized by the upper section (19) of the riser (18) being cylindrical, especially with a circular or rectangular cross section, and being provided with a piston (22) or a diaphragm (29) forming a displacable barrier between the spillage (28) and an air pocket (37) located thereabove, and where the air pocket (37) functions as a buoyancy body.

4. Device according to any one of claims 1-3, characterized by a drainage hose (23) being connected to the displacable barrier (22,

29)

.

5. Device according to any one of claims 1-4, characterized by the riser (18) being made of a cloth material which is covered by a reinforcing fishnet stocking (35) or provided with integral flexible reinforcement.

6. Device according to claim 5, characterized by the fishnet stocking (35) being fasten at the top, respectively the bottom of the riser (18).

7. Device according to claim 5 or 6, characterized by the upper end (19) of the riser (18) being made of reinforced plastics.

8. Device according to claim 7, characterized by the upper end (19) of the riser (18) being provided with a cover (20) having a valve (24) for conection of a drainage pipe (at 30).

9. Device according to any one of claims 1-8, characterized by the riser (18) being provided with at least two longitudinally spaced apart ring-shaped floats (36).