The present invention relates to a trawl-shaped (sub¬ stantially Y-shaped) device for collecting oil from the surface of the sea, where the device has a funnel-shaped inlet opening at the one end and a collection portion at the opposite end and where the device is adapted to be drawn floating along the surface of the sea by one or more tug vessels and is provided with a top portion covered over a substantial portion of the longitudinal dimension, which is adapted to glide on or just at the surface of the sea and which is provided with downwardly hanging, skirt-forming, weight-loaded side walla and an essenti¬ ally open bottom portion.

From NO Patent Specification 126,443 a trawl-shaped device is known for the collection and removal of oil from the surface of the sea. The device is in the form of a funnel-shaped, flat- pressed bag provided with an upper portion of a flexible, oil- tight canvas and a bottom portion of a material freely permeable to water. The upper portion of the device is adapted to glide along the surface of the sea and to form guide means for leading a concentrated stream of oil over towards the collection portion of the device. The collection portion of the device which is located in the rear end of the device, is provided with an open bottom for the escape of the water which is collected below an upper oil floe. The collection portion can be emptied of

collected oil via suitable equipment such as an "oil skimmer" to a following escort vessel with associated storage tanks for collected oil.

From NO Patent Specification 148,862 a similar device is known in the form of a funnel-shaped, flat-pressed bag provided with an upper portion of a flexible, oil-tight canvas and a bottom portion of a material freely permeable to water. A series of valves is shown for venting air which has collected on the under side of the upper portion of the bag. The collection portion constitutes a separate segregatable bag which when it is full of oil can be uncoupled from the device and handled sepa¬ rately with suitable collecting means.

With the present invention the aim is a solution which is specifically designed for use under unfavourable weather con- . ditions with relatively large high wave heights. In the previously proposed solutions the device will be easily damaged or made more or less inactive by large wave heights, where the sea waves can to a large degree roll in over the device and can expose the latter to heavy forces both from the upper side and the lower side. In such cases the proposed valve arrangements are of little significance.

According to the invention the aim is a solution which can permit large portions of the masses of waves to slap over the front end of the device and can nevertheless be collected in an effective, controlled manner in the device behind the front end of the device.

The device according to the invention is characterised in that the device has an approximately inverted U-shaped cross- section comprising a top portion and opposite side walls, that the top portion of the device is formed by a sectionally divided, tension-absorbing network of longitudinal and transverse tension means and secured to the sectionally divided tension means, substantially equivalently divided carpet sections, which comprise flexible, tight or relatively tight canvas material sections with asociated reinforcing material, the canvas material sections being without mutual connection longitudinally of the device and preferably also laterally of the device, while the

canvas material sections are connected to the tension means at the leading front edge and side edges of the section, but are relatively freely moveable relative to a canvas material section following in the direction of tension, to form an intermediate opening between associated edges of the carpet sections.

By providing for intermediate openings between the carpet sections the waves can be allowed to slap in over the top of the front end of the device and be led from the upper side of the device to the lower side of the device via the said intermediate openings between successive following carpet sections.

It is preferred that the carpet section, reckoned in the direction of tension, has a shorter front edge side than back edge side with at the start equivalent backwardly diverging longitudinal sides, and that the back edge side of a carpet section on the under side overlaps the front edge side of a subsequent carpet section and preferably is connected to the tension means of the front edge side of the subsequent carpet section via essentially vertically extending connecting lines.

Further features of the invention will be evident from the following description having regard to the accompanying drawings, in which:

Fig. 1 shows schematically in a plan view a device according to the invention during drawing of the latter along the surface of the sea by means of two front vessels and with a following vessel for gathering up the collected oil.

Fig. 2 shows an alternative construction of the device illustrated in an equivalent view to Fig. 1.

Fig. 3 shows in perspective a section of the top portion of the device.

Fig. 4 shows schematically the device itself in plan view, without pulling lines and associated vessels.

Fig. 5-7 show cross-sections along the lines 5-5, 6-6 and 7-7 of Fig. 4.

Fig. 8 shows a longitudinal section along the line 8-8 of Fig. 4.

Fig. 9 shows a side view of the device.

Fig. 10 shows a section of a connecting point in the device.

Fig. 11 shows an insert member for use in the device according to the invention.

In Fig. 1 there is shown a planar section of a construction of the top portion for a collection device 10, which in use during the collection of oil 12 on the sea surface 14, is towed by two vessels 16, 18 by means of tow lines 20.

The collection device 10 has a funnel-shaped construction, the broad end forming an inlet opening 22, which is set against the oil floe, while the narrower end forms a collection well 24 for the oil which thereafter is pumped over into a storage vessel 21 situated at the rear.

The device 10 is furthermore open downwards towards the bottom, but is sealed off against the lateral discharge of oil in that its longitudinal side edges 26, 28 are provided with up¬ wardly projecting blocking walls and side walls or skirts 82 of sealing material hanging downwardly into the sea.

Above the device 10 is formed of a network construction of longitudinal 30, 32, 36 and transverse 39, 40, 41 tension means which thus form sections 54, 56, 58. These sections are further¬ more substantially totally covered by a system of carpet sections of a laminated tight construction the front edge of which is sealingly fastened to the adjacent transverse tension means, and to the two longitudinal tension means, while the rear edge of the carpet section is substantially freely moveable.

The device is maintained floating on the sea surface by means of floats (not shown in Figs. 1 and 2) secured to longi¬ tudinal side edges 26, 28 and to the transverse tension means of the device.

When the device is towed through the sea the oil/water mixture viewed ideally, that is to say when there are no waves, will be moved largely below the carpet sections forwardly towards the collection well. When there are waves these will slap over the front edge of the carpet sections, running over the carpet and downwardly below the succeeding section in the series.

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The planar section construction of the device 10 arises by means of a number of longitudinal 30, 32, 34, 36 and transverse 38, 40, 42 tension means respective ends of which are secured to adjacent cross points 44, 46, 48, 50, 52 which are constituted by ring elements.

The tension means can consist of cables of wires, chains or the like. The cross points are constituted by ring elements and the tension elements which can be disengageably fastened to the ring elements, such as by means of spring hooks.

When the construction is stretched out the top portion forms a network of sections 54, 56, 58 which are defined by the longi¬ tudinal 30-36 and transverse 38, 40, 42 tension means. The tension in the rings makes the network form a crow foot connec¬ tion.

The funnel shape arises in that the sections 54, 56, 58 close to the inlet end 22 of the device 10 are designed with substantially rectangular planar sections so that the front portion of the device has parallel side edges 26, 28, while the edge sections 60, 62, 64, 66 at the collection opening 24 of the device 10 are designed with trapezoidal and triangular planar section in order to establish the narrowing off or converging device portion rearwardly to the collection end 24. Thus the device forms as shown in Fig. 1 an approximate U shape. In order to ensure also that the funnel portions where the converging contraction begins, are maintained in a satisfactory stretched out position tow lines can be fastened in addition from extra towing vessels to these rear portions of the funnel. If necessar trawl doors or similar means can be mounted along outer sides of the device in order to contribute to maintaining the device stretched out.

In fig. 2 there is shown an alternative construction of the device where there is formed a V-shaped funnel viewed in the direction from the inlet end 22 and to the collection well 24 in that the peripheral sections are designed with planar sections like trapeziums and triangles on each side of a middle row of

substantially rectangular sections. In this construction it is not necessary to have extra auxiliary means for stretching out the rear portions of the device.

Transverse tension means 38-42 of each section are also provided with a number of floats 75 (see Fig. 3) having mutual spacings.

As mentioned above each individual section of the network of the device 10 is essentially wholly covered by a system of carpet sections. The covering of each section is shown in Fig. 3 which illustrates a view of two of the adjacent longitudinal sections 56, 58 according to Fig. 1. The Figure shows the network sections in a fixed position with the longitudinal tension elements 32, 34 and the transverse tension elements 39, 40, 41.

Each section 56, 68 in the network is covered by a carpet section 70, 72 of a flexible, tight or relatively tight canvas material having associated reinforcing material, in order thus to build up the afore-mentioned covering of the whole device.

On viewing the carpet section 70 this is fixed and connected to the associated tension elements, it being secured to the leading front edge 39 and the two side edges 32,34, while the rear edge 74 of the carpet section 70 is relatively freely move¬ able relative to the carpet section 72 following in the direction of tension. The carpet section 72 which follows the section 70 is fastened to the tension means 33, 40, 35 respectively while the rear carpet edge is represented by the reference numeral 75. Each one of the sections in the network is covered in this way.

When a mixture of oil and water from ahead slaps in over the afore-mentioned carpet-covered sections the free edge end 74, 75 of the canvas material will be pressed downwards and form an arcuate flexure such as shown in Fig. 3, and the flexure will be greatest at the rear edge of the carpet section. This means that a large portion of the oil-water mixture will flow in under the carpet associated with the subsequent/rearwardly disposed section, while another portion of the fluid, as a result of a possibly continued ripple of waves, flows in on the top side of the carpet for the subsequent section. The admission of oil in

under a subsequent section is gradually reinforced as the mixtur approaches the collection well, so that more and more of the oil becomes situated under the carpet when it approaches the well.

In order to increase the flexure of each carpet section 70, 72 the canvas can have a front edge side shorter in the tension direction than the rear edge side and with longitudinal sides which diverge in the rearward direction, that is to say that there is formed a trapezoidal planar section. In addition the rear edge side of a carpet section according to a preferred construction can form an overlap on the under side of the front edge side of the subsequent carpet section. That is to say that the said looser back edge side passes a given length in under th next carpet section.

Preferaby the rear edge side 74, 75 of a carpet section can be connected to the tension means 40, 41 of the subsequent carpe section by means of substantially vertical connecting lines 77, such as shown in Fig. 3.

Even if it is preferred that the carpet sections have the afore-mentioned trapezoidal planar section, they can also be designed with a rectangular or similar form. When the device is constructed so that there is large distance between the two side edges the free hanging carpet flap will be set with a natural arcuate flexure as a consequence of the inherent elastic properties of the carpet canvas material.

The carpet section itself can be made of a tight canvas material which is covered on the one or both sides with a mesh net of suitable mesh size. It is especially preferred to cover the tight material with a net of coarce mesh on the under side, and a more fine-meshed net on the upper side of the canvas. In this way the frictional resistance increases against movements o the oil/water, so that movements and gushings of fluids are moderated and the oil comes rapidly to rest beneath the carpet during its movement towards the collection well 24. In order to moderate the movements of the oil still further there can be arranged beneath the canvas additional movement-restraining downwardly hanging strips.

Preferably the sections of canvas material are without mutual fastening longitudinally of the device and preferably also laterally.

Reference shall now be made to the Figures 4-8. Fig. 4 shows a planar section of the basic construction of the device 10 where and the positioning of extra guide jackets 80 are drawn in. The carpet sections which are arranged out towards side edges 26, 28 of the device are provided with extra downwardly hanging guide jackets 80 in order to conduct the oil forwards towards the collection well 24. These guide jackets 80 are arranged in an oblique position such as shown in Fig. 4, and so that a guide jacket on one section overlaps on the inside of the guide jacket of a subsequent section. Thereby the oil will be concentrated and forced inwardly towards the middle of the device something which facilitates the collection. For the V-shaped construction of the device 10 which is shown in Fig. 4, the inwardly sloping outer jacket portion 82 ought to form an angle with the longitudinal axis (8-8) of the device which is within 27.5-35 degrees so that the flowing in of the oil to the collection well 26 is optimised. Furthermore the angle of the guide jackets 80 relative to the longitudinal axis (8-8) through the device ought not to exceed 27.5 degrees.

Figure 5-9 show respectively front, middle and rear cross- sections through the device according to Fig. 4.

Thus Fig. 5 shows a cross-section through the device along the line 5-5 of Fig. 4. In this front portion of the device, that is to say in the sections 54, 56, 58 according to Fig. 1-2, where the sea first slaps in, it is preferred to use a type of carpet sections 70, 72 (Fig. 3) where the rear edge 74, 75 of the carpet is suspended by means of fastening lines 77 in the front edge 40, 41 of the subsequent section, as is shown above. This is an advantage since here, in the front portion of the device the movements in the sea/oil can be relatively powerful. By using such a suspension exposure of the canvas material to movements which increase the damage of wear and tear is avoided. From the

Figure the downwardly hanging inner guide jackets 80 as well as the outer jackets 82 which hang downwards along the side edges 26, 28 are evident.

Fig. 6 shows a section along the line 6-6 according to Fig. 4. This section is made somewhat longer at the rear and shows that also here there are installed the afore-mentioned suspensio lines 77. The movements of the oil/water will however be somewha calmer so that the rear edges of the canvas material sections ca now be flexed into an arcuate shape without the suspension as shown in Fig. 5.

Fig. 7 shows a cross-section of the device closer to the collection well 26. It is evident that the inner guide jackets 8 and the outer guide jackets 82 now find themselves closer to¬ gether than shown in the previous Figures, since the device is now narrowed off in towards the collection well.

Fig. 8 shows a longitudinal section through the device according to the invention. The downwardly sloping graduated pat for the carpet sections 70, 72 is clearly evident.

In Fig. 9 there is shown a vertical side view of the device according to the invention. As illustrated the depth for the outer sealing jackets 82 increases gradually from inlet opening 22 of the device and to the collection well 24. This increase is necessary since it has been found that the oil will accumulate i height when it approaches the collection well as a result of the device 10 narrowing off and forming a thicker and thicker layer of oil. This is in contrast to previously known solutions where it has been recognised that thicker layers with oil have been difficult to achieve.

In Fig. 10 there is shown a cross point or fastening point in the form of a common fastening ring 100 for spring hook 101 associated with a number of tension means 32a, 32b, 46a, 46b having associated spring-loaded catch member 102 or similar readily fastenable and readily releaseable fastening means. The fastening ring 100 constitutes together with the longitudinal tension means 32a, 32b and the transverse tension means 46a, 46b a crow foot connection for distributing the forces of tension rectilinearly from fastening point to fastening point. By means

of the illustrated arrangement it is possible to effect readily the assembly and disassembly of each carpet section individually for the device. Carpet fastening means 103 are shown in the form of anchoring sleeves which are crimped into place on the tension means at locations adapted for this purpose with suitable inter¬ mediate spaces in the longitudinal direction of the tension means. In other words the aim is to fasten the carpet sections to the tension means at locally defined positions along side edges of the carpet sections in order to create longitudinal venti¬ lation openings between the carpet sections. In the front edge of the carpet sections corresponding fastening means 103 can be fastened, but with mutually little distance between the fastening means. Alternatively the front edge of the carpet sections can be designed with a continuous guide which the tension means is threaded through endwise.

In Fig. 11 there is shown a set of (three pieces) carpet sections 105 of a particular design. In contrast to the remaining carpet sections, as indicated above, the carpet sections 105 are designed without canvas material and are formed with mesh-shaped through-flow openings. More specifically each carpet section 105 is made up of a top layer and/or a bottom layer of a number of longitudinal and/or transverse, mutually parallel float lines and an adjacent net or similar mesh-shaped material, which is sewed together into a coherent unit. Alternatively the net can be pro¬ vided with a layer of float lines on each of its opposite sides or a layer of float lines can be provided with nets on opposite sides. Relatively coarse meshed and relatively fine meshed nets can be employed, as required under different working conditions. The said set of carpet sections can be utilised in the device as a wave-moderating element which has the possibility of consider¬ able through-flow for water and oil which necessarily is to be found on the upper side of the carpet sections and on the lower side of the carpet sections respectively. The set of carpet sections is shown in Fig. 11 in the form of a coherent unit in order to illustrate that the whole unit can be fastened in directly between the front edge of the device and the associated tension lines as shown in Fig. 1 and 2. By means of fastening

means and fastening rings, correspondingly as shown in Fig. 10, the carpet sections with associated tension means can be assembled and disassembled as required in a ready manner. Alter¬ natively common tension means can be employed and the carpet sections mutually replaced as required via the said fastening means 103.

When the device according to the invention is utilised it i towed, with or without the insert member indicated in Fig. 11, towards the contaminating oil floe, and the waves slap ϊn over the upper side to the first cross row of carpet sections. Alread at the next row some of the oil has entered beneath the carpet, some slapped over the carpet and the portion which flows in unde the subsequent canvas, gradually increases as the oil moves towards the collection well. At the same time there occurs an increasing moderation in the movements of the waves and the conditions at the well can for example be only slightly pitching

It is evident that since the oil gradually becomes located under the carpet, the evaporation from this portion of the oil mass which is covered by the carpet decreases. The device according to the present invention will therefore be able to improve oil collection under otherwise unfavourably warm climati conditions. Furthermore the openings situated in the back edge o each section will facilitate the possibility to ventilate gases and vapours which are formed by evaporation beneath the carpet.