MXPA98001162A - Method and apparatus for foaming a superficial floating surface of a surface of a - Google Patents

Abstract

The present invention relates to a method for recovering a floating surface layer of a body of water, particularly a surface layer comprising a floating contaminant, such as oil, a collection compartment (A) having a dam or foaming weir ( K) in its upper part in the body of water and filled with water. With the dam or foamed dump in an overflow position in relation to the surface of the body of water, the water is discharged from the collection compartment (A), so that the collection compartment can be again filled from the surface of the body of water with the water flowing over the dam or foaming weir (K). The apparatus for carrying out the recovery comprises a collection container (11.31), which is immersible in a body of water and defines the collection compartment (A) and which has a dam or foaming weir (K), which forms an inlet towards the upper end of the collection compartment (A), and means (17, 18, 35, 36), such as a reversible pump, to discharge water from the collection chamber

Description

METHOD AND APPARATUS FOR FOAMING A FLOATING SUPERFICIAL LAYER OF A WATER SURFACE DESCRIPTION OF THE INVENTION This invention relates to a method and apparatus for foaming a surface layer of a body of water, such as for recovering oil floating on water . The invention will be described with particular reference to the aforementioned application but it is also useful for recovering other materials besides oil. More particularly, the invention relates to a technique which comprises providing in the body of water a submerged collection compartment having an inflow opening defined by the foaming dam or weir, the crest which is located on the surface of the water. The dam or foaming spill is forced to take an overflow position in relation to the surface of the water while discharging water from the lower portion of the collection compartment. The oil and water flowing over the dam or foam dump fill the collection compartment on top of it. The influx of oil is controlled by controlling the position of the foamed in relation to the water surface and controlling the discharge of water from the lower portion of the collection compartment.

REF: 26746 In the collection compartment, oil, by virtue of its lower density in relation to water, forms a layer of oil on top of the underlying water. The oil collected in the collection compartment can be removed in different ways. For example, it can be pumped intermittently or continuously into the appropriate larger container or storage container. The main object of the invention is to provide an improved method and apparatus for carrying out the technique described above. The features of the invention are illustrated in the accompanying schematic drawings and will be described below with reference to the Figures of the drawings. Figures 1 to 3 schematically illustrate a frothing apparatus of the invention in a different position in a body of water on the surface from which a floating oil layer is to be recovered; Figures IA and 2B are views similar to those of Figures 1 and 2 respectively, showing a modification of the frothing apparatus; Figures 4 to 7 show a preferred embodiment of the frothing apparatus according to the invention. As schematically illustrated, Figures 1 and 2, the frothing apparatus according to the invention comprises a collection container 11 of the side wall includes a vertical bottom part, generally cylindrical 12, and a vertical top, usually cylindrical, 13, similar, which moves telescopically inside the lower part. The lower end of the upper part is provided with an outwardly directed annular rim 14 in sealed engagement with the interior of the lower part 12 and the upper end is provided with an annular floating body 15. A lower wall 16 of the collecting container 11 it has a central opening 17 through which a pump 18 can pump water in and out of the upward opening of the collection chamber A formed by the collection container. Associated with the collection container 11 is a horizontal cover plate 19 with a central opening 20. The cover plant 19 is rigidly connected to the lower part of the container 12 through the support members 19A indicated by the thin lines in FIG. Figures 1 to 3. A collection container 21 shown only partially is sealedly connected to the cover plate 19 so that a supply portion 21A of the container is placed directly above the cover plate 20. The collection container 21 can be, for example, a tubular "tank" floating film material or flexible sheet and in a manner to be described serves to receive the oil that is transferred from the collection container 11. A sealed ring 22 placed around the opening 20 provides a seal between the collection container 21 and the cover plate 19. Also associated with the collection container 11 is a second annular floating body 23 which is located within and substantially concentric with the said first floating body 15 and having a hanging annular skirt 24. As shown in FIG. Figures 1 to 3, this skirt 24, which has some elasticity, is frustroconical with the small end directed downwards, but may have other shapes. The second floating body 23 is attached to the first floating body 15 by means of radial strips or belts or other flexible connection means 25 so that they move substantially freely up and down relative to the floating body 15. The liquid can passing through the annular space R between the two floating bodies 15 and 23 without being substantially obstructed by the connecting members 25 because they cover only a small portion of the space. In addition to the collection container 11 described above with the associated components, the skimming apparatus comprises a number of three, for example, floating bodies, and subsequently called stabilizing bodies and designated as 26, which are spaced apart from the collection container 11. and rigidly connected to the lower part 12 of the collection container. These stabilizing bodies 26 have such buoyancy that they project above the surface of the water in the equilibrium position shown in Figure 1, in which the collection container 11 is substantially completely filled with water. In plan view there is a passage between the stabilizing bodies 26 along which the unobstructed flow of the body of water surrounding the apparatus in the upper portion of the collection compartment A is possible. Each stabilizing body 26 is shaped like a vessel cylindrical tumbled downwards, the uppermost portion of which is closed and contains a floating block 27 of a lightweight material, such as expanded plastic, while the lower, submerged end is open. The stabilizing bodies are arranged so that the space B below the floating body 27 will be filled with water when the frothing apparatus is placed in the water. A non-return valve (not shown in the drawing) on the stabilizer body facilitates the filling of that space with water by opening it to allow the air trapped in it to escape when it tends to develop a subatmospheric pressure.

When the frothing apparatus is going to be used to recover oil it is placed in the body of water from which the oil will be recovered. In Figure 1, the apparatus is shown in an inactive condition, that is, in a position in which the collection container 11 has been filled with water through the opening of the lower wall 17 and in which the floating body 15 on the upper part 13 of the collection container is sealingly coupled to the cover plate 19. In this position, the pump 18 starts to pump water down from the collection container 11 through the opening 17. The discharge of water downwards further lowers the water level in the collection container 11 so that a water weir is formed down the floating body 15. Consequently, a difference in the water levels inside and outside the body will be created. 15. The difference thus created in the liquid levels in the collection container 11 and the body of water surrounding the collection container of the influence on the upper part 13 of the collection container n in two aspects. First, the floating force tends to raise the floating body 15 which is slightly reduced, because the volume of the liquid displaced by the floating body is reduced in proportion to the difference in levels; the portion of the floating force resulting from the partial immersion of the floating body in the liquid in the collection container is reduced as a consequence of the decrease in the level of liquid in the collection container. Second, the hydrostatic head or hydrostatic pressure acting on the upper side of the flange 14 of the upper part of the harvesting collector 13 will become larger than the hydrostatic head or hydrostatic pressure acting on the lower side. Consequently, the flange 14 and therefore the entire upper part of the container 13 will be subjected to a resultant downward directed force. As a consequence, the upper part 13 of the collection container 11 will be displaced downward relative to the lower part 12. Although the floating force acting on the portion of the floating body 15 submerged in the body of water out of the top of the collector of collection 13 will increase slightly, the floating body 15 will be, when a certain difference in levels has been reached, it will take a completely submerged position below the surface of the body of water, so that the surface layer of oil-water of the body of water will flow to the collection container 11 on the crest K of the blowout dam formed by the floating body 15.

The liquid, oil and water, which overflows the floating body 15 will be deflected downwards in the collection compartment A by the second internal floating body 23 and its skirt 24. Because the cross sectional area of the flow passage increases towards below, the speed of the downwardly flowing liquid will decrease rapidly, thereby allowing the lighter oil to pass under the lower edge of the skirt 24 and collect on the surface of the space S defined within the floating body 23 and its skirt 24. This is shown in Figure 2. Naturally, the oil can also be collected in the annular space R between the floating bodies 15 and 23. The space S downwards of the floating body 23 and its skirt 24 constitutes a zone of calm or stabilization in the which oil can form a coherent layer without disturbance caused by the liquid flowing radially inward on the floating body 15. The pumping to af outside the upper end of the collection container 11 and the resulting reduction in water volume also results in a reduction of the total weight of the water-filled skimming apparatus. Accordingly, the stabilizing bodies 26 will tend to elevate the entire frothing apparatus to a slightly higher level. Nevertheless, this elevation is counteracted as a consequence of the fact that the volume of water accommodated in the lower portions B of the stabilizing bodies 26 will remain attached to those bodies and thus also will rise and therefore act as extra weights added to the weight total of the frothing apparatus. The interaction between the forces with which it acts, on the one hand, on the upper part of the container 13, which move easily in vertical direction with respect to the lower part 12 and the elements rigidly connected thereto, and, on the other side , in the skimming apparatus as a whole, provides sensitive and rapid self-regulation of the elevation of the floating body 15 and thus the crest K of the foaming dam, resulting in a rapid equalization of the liquid tributary in the collection container towards the effluent thereof. If, at any given moment, the effluent in the collection container was very fast in relation to the effluent, the difference in the levels (or, more precisely, the difference in hydrostatic pressure) between the liquid in the collection container and the body of the surrounding liquid will be reduced, so that the floating body 15 rises and reduces the tributary. If instead of the effluent being very fast in relation to the tributary, the floating body 15 will be more submerged to increase the tributary. As a consequence of the free vertical mobility of the upper part of the easily mobile container 13 with the foaming dam formed by the floating body 15 in relation to the remaining completely mobile part of the skimming apparatus, including the volumes of water accommodated in the collection container 11 and the stabilizing bodies 26 the elevation of the crest K of the foaming dam is self-regulated in a very sensitive manner depending on the changes in the level of the body of surrounding water and the level of the liquid in the collection container. After the apparatus has been operated for a short or prolonged period of time to collect oil in the collection compartment, the pump 18 is inverted to pump water from below to the collection container 11. The increase in liquid level in the The collection container will then make the floating bodies 15 and 23 engage the lower side of the cover plate 19. The first floating body 15 will serve as a shut-off valve between the interior of the collection container 11 and the surrounding body. Due to the increased volume of water in the collection container, the entire frothing apparatus will initially move downward in the body of water, but the continuous downward movement will be counteracted by the floating force that increases on the stabilizing bodies 26 resulting from its movement down. The most superior liquid layer in the collection container, ie, the oil layer in the space S within the second floating body 23 and its skirt 24 will be forced through the opening of the cover plate 20 and through the the feeding portion of the container 21A and the associated sealing ring 22 in the collection container 21 floating on the surrounding body of water. This is shown in Figure 3. The ejection of the light upper liquid layer towards the collection vessel 21 by introducing a heavier displacement liquid from below to the collection chamber A can take place in a single continuous passage. However, the ejection can also take place immediately in one or more successive steps by temporarily interrupting the introduction of the displacement liquid. During interruptions or off-duty periods, when substantial flow does not take place in or out of collection bin A, small droplets of oil or oil clusters may migrate evenly to the surface in space S. To complete the flow of oil transfer to the collection vessel 21 the pump 18 can again be inverted so that the operation described above can be repeated. The cover plate 19 and, accordingly, the feed portion 21A of the collection container 21 will resume the raised position shown in Figure 2, so as to avoid the inverted flow of the contents of the collection container through the opening of the cover plate 20. The inverted oil flow from the collection vessel 21 to the collection container can be prevented by suitable valve means associated with the container. The change of the accumulation of oil in the collection container 11 as shown in Figure 2 to the transfer of the accumulated oil to the collection vessel 21 as shown in Figure 3 and also the change back to the accumulation mode can take place in different ways and using different means. For example, the height or thickness of the accumulated layer of oil can be determined by verifying the power consumption of the motor that drives the pump 18, and switching to the transfer mode can take place automatically in response to the detection of a given height of the cap. Switching back to the accumulation mode as shown in Figure 2 can also take place automatically depending on the energy consumption of the pump motor. Figures 1 to 3 are primarily intended to illustrate the principles of the method and apparatus according to the invention, rather than to show a preferred embodiment of the invention. It should be noted, however, that it is possible, within the scope of the invention without departing from what is shown in Figures 1 to 3. For example, the transfer of the oil (or other floating contaminant or other matter to be recovered) from the The collection container can take place more or less continuously using a separate pumping apparatus in the feed from which it is placed in the accumulated oil layer. In addition, the collection container 11, which is variable with respect to its height and consequently with respect to its volumetric capacity, does not necessarily need to be cylindrical or comprise two separate parts as shown in Figures 1 to 3. Figures A and 2A show additional floating bodies 28 which are provided in separate locations around and radially outside the first floating body 15. Those additional floating bodies 28, which are sufficiently separated to obstruct the radial tributary to the collection container 11 of the liquid body surrounding only minimally, are attached to the upper part of the collection container 12 (or directly to the floating body 15) by cables or other suitable means as indicated in broken lines at 29 in Figure IA. The union of the floating bodies 28 and their shape are chosen so that during normal operation, as can be expected when the water surface is very uniform, the additional floating bodies arise in the water only slightly or not at all so that they do not apply significant force upwards towards the top of the collection container. In other words, during the normal operation of a frothing apparatus, the additional floating bodies 28 have no significant influence on the elevation of the crest K of the foaming dam. However, should there be a sudden increase in the level of the water surface near the collection container 11, for example when a wave reaches the frothing apparatus, the cables or attachment means 29 will prevent the additional bodies 28 from moving upwards. in relation to the upper part of the collection container 12. Accordingly, the additional floating bodies 28 will apply an optional force upwards to the top of the collection container to cause the floating body 15 to engage the cover plate 19 and prevent an excessive tributary of liquid to the collection container 11. Preferably, the additional floating bodies 28 are interconnected by means of a cable or other suitable connecting means that extend around the collection container, suitably so that they can move vertically in mutual relation but are kept circumferentially spaced in a suitable manner and in suitable proximity to the chalk K of the foaming dam. Figures 4 to 7 show schematically an example of a mode of the skimming apparatus according to the invention, Figures 4 to 6 show the apparatus in operating positions corresponding to those shown in Figures 1 to 3, while Figure 7 It is a plan view of the device. With respect to its main features, the apparatus shown in Figures 4 to 7 correspond generally to those of the apparatus of Figures 1 to 3, both with respect to the basic structure and with respect to the basic operation. In the embodiment of Figures 4 to 7, the collection container 31 defining the collection compartment A is a structure which collapses vertically in the form of an accordion. Its side wall 32 is made of flexible film material or sheet but substantially inextensible or wound around a number of separate, rigid, circular rings 33 of plastic or light alloy. In the extended condition as shown in the Figures, those rings are separated but when the apparatus is disassembled they can be placed close to each other or even in a common plane. The lowermost ring 33 is secured to the lower plate 34 having an opening 35 in which a pump 36 is placed. On the uppermost ring 33 is mounted an annular floating body 37 which forms the foaming prey and its crest K and corresponds to the first floating body 15 of the apparatus shown in Figures 1 to 3. Within the upper portion of the collection container 31, and placed substantially concentrically with the collection container and with the floating body 37, is found a second annular floating body 38 with a sloping skirt 39 corresponding respectively to the floating body 23 and the skirt 24 in Figures 1 to 3. Like the collection container 31, the skirt 39 is a collapsible structure made of film or sheet flexible but substantially non-extensible wound around a number of separate rigid rings 40. In this embodiment, just as the floating body 38 is attached to the floating body 37 or the uppermost ring 37 by means of belts or bands or the like so that they can move freely up and down relative to the floating body 37 but always maintain a position substantially concentric with respect to that body. However, the space between the floating bodies 37 and 38 and the space within the floating body 38 and its skirt 39 are designated respectively as R and S. As in Figures 1 to 3 a cover plate 41 with an opening 42 is arranged in a stationary position in relation to the lower plate 34. More particularly, the lower plate 34 and the cover plate 41 are releasably secured to the opposite ends of six uniformly circumferentially spaced vertical tubes 43. Inside the tube ring the floating body 37 and the upper portion of the side wall 32 of the collection container 31, and in this way also the floating body 38 and the skirt 39 can move up and down. The pairs of tubes 43 support three stabilizing bodies 44 (corresponding to the stabilizing bodies 26 in Figures 1 to 3) through three intermediate pairs of clamps or upper and lower supports extending radially outwards 45. As shown better in Figure 7, the stabilizing bodies are uniformly circumferentially spaced around the collection container 31 and spaced radially outwardly thereof. Each stabilizing body 44 is arranged around the upper portion of the associated tube 46. Like the collection container 31 each stabilizing body 44 constitutes a vertically collapsible structure having a side wall 47 made of a film or sheet material wound around separate circular rigid rings 48. The uppermost portion of the space defined by the side wall 47 is occupied by a floating block 49 of expanded plastic, for example, while the portion of that space that is below the floating block 49 is open and intended to be filled with water during the operation of the frothing apparatus. To secure the side wall extending to the lowermost ring 48 is releasably secured to the tube 46. A non-return valve 50 is provided at the upper end of each tube 46 and arranged to open to allow air in the space below of the floating block 49 escaping upwards when this space is going to be filled with water but to close when a subatmospheric pressure is developed so that the escape of water is prevented. The filling with water ventilation can take place throughout as indicated by the arrows in Figure 4. As in the embodiment of Figures 1 to 3 a collection container 51 is sealedly connected to the cover plate 41 so that the feeding portion 51A of the container is directly above the opening 42, which is surrounded by a sealing ring 52 of the container. The apparatus shown in Figures 4 to 7 operates essentially in the manner described above with reference to Figures 1 to 3. However, a certain difference can be observed in the fact that with the illustrated cylindrical shape of the collection container 31 does not exist a differential pressure surface corresponding to that which is provided by the opposing thrust surfaces of the flange 14 in Figures 1 to 3. Instead, a downward pulling force acting on the floating body 37 will occur due to the Pressure difference across the flexible side wall 32 of the collection container will deform the side wall inwards and therefore directs the rings 33 towards each other so that the entire collection container will be held vertically. If desired, however, a differential pressure surface can be provided by making the collection container 11 narrower in the upper portion than the lower portion. As is evident from Figures 4 to 7 the skimming apparatus according to the present invention can be made as a light weight construction, easily assembled and mountable and easily transportable description. In addition, this can occur at a low cost. Therefore, it is economically realistic to produce the apparatus in large numbers and to park them in places which can be easily transported to producible places of operation where they can be easily prepared for their operation.

Due to the omnidirectional tributary to the collection container and the rapid separation of the lighter material in the collection container, a high collection capacity is possible. In the embodiments described above of the frothing apparatus, the elevation of the crest of the foaming dam K is self-regulating substantially under the action of three different forces, namely the force of gravity or weight, a hydrostatic buoyancy force and a pushing force. hydrostatic The force of gravity on the top of the collection container, which moves vertically independently of the rest of the collection container and the volume of liquid contained therein, constantly tends to move the top and thus the crest of the dam of foaming down. On the other hand, the floating force acting on the upper collecting container part tends to move this part and thus the crest of the foaming dam K upwards. The flotation force is composed of two vertical components, namely a component produced by the liquid in the collection container and a component produced by the liquid in the surrounding body of water. In the condition shown in Figures 1 and 4, in which at each level the hydrostatic pressure or hydrostatic head within the collection container is the same as in the surrounding body of water, the sum of the two components of the flotation force equal the force of gravity plus, if applicable, the force under which the floating body 15 d 23 engages the cover plate. When the hydrostatic pressure in the collection container is less than the hydrostatic pressure in the surrounding water body, the third force, in the form of a downward force determined by the pressure difference also exerts an influence. In the embodiment of Figures 1 to 3, this third force acts through the intermediate of the flange 14. In the embodiment of Figures 4 to 7, this force is provided by the side wall 33 of the collection container 31 when pressed towards in between the rings 33 and therefore it contracts horizontally so that the collection container as a whole contracts vertically. However, it is within the scope of the invention to produce a similar self-regulation in other ways. For example, the last mentioned force, ie the third force, can be dispensed by omitting the differential thrust surface so that only a floating force proportional to the pressure difference between the collection container and the surrounding water body exerts a influence.

A further possibility is to replace the flotation force, or combine this with, a force that constantly acts on the top of the collection container and thus, on the crest of the foaming dam K, such as a spring force. Another possibility is to apply a force directed downwards that acts constantly, that is to say, a force that coactúe on the force of gravity. Other purely structural modifications are also possible within the scope of the invention. The illustrated annular shape of the crest of the foaming dam and the deflection member located inwardly of the foaming dam and constituted by the floating body 23 or 38 with the skirt 24 and 39 is very advantageous but not necessary. Accordingly, it is possible to allow the tributary to the collection compartment to take place through a crest of the foaming dam K that does not extend along the entire periphery of the collection container but only along a portion of it (preferably through it throughout the larger portion). The deflection member can then be limited to a corresponding portion of the circumference. In a further embodiment, which is not shown in the drawings, the frothing apparatus is designed to move in a predetermined direction relative to the body of water during the collection of the surface layer. For example, the apparatus may be towed or moved by an integrated prepulsing unit, or the water body may be a body of fluid water in which the frothing apparatus is held in a stationary position. If the frothing apparatus is provided with an integrated propulsion unit, this unit can also be used to pump water outward, and possibly also to the collection container. In the additional embodiment, the floating body forming the foaming dam extends only over a portion of the circumference of the collection container, namely about 50 to 75% of the circumference. During the collection of the oil or other surface layer to be collected, the foaming dam is on the upstream side, so that it is directed in the direction of movement of the frothing apparatus in relation to the body of fluid water, and the material of Harvesting is discharged into a collection vessel in the opposite direction or downstream through a horizontal outlet provided in the portion of the circumference of the collection container that is not subtended by the foaming dam. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (29)

1. A method for foaming a floating surface layer of a body of water, particularly a surface layer comprising a floating contaminant, such as oil, comprising: placing in the body of water a collection container having a collection compartment (A ) and a foaming dam or weir (K) forming an upper part of the collection container and delimiting the collection compartment upwards, and filling the collection compartment with water, forming and maintaining a well or water collector in the compartment of collection (A), and having the foaming dam or weir (K) take an overflow position in relation to the surface layer to allow the surface layer to flow over the foaming dam (K) to the well or collector water, characterized in that it allows the prey or foaming weir K to move vertically in relation to the underlying part of the collection container.

2. The method according to claim 1, characterized in that it controls the elevation of the crest of the dam or foaming weir (K) by applying a vertical force to the foaming dam, the amount of which varies in proportion to the difference in the pressure or hydrostatic head between the collection compartment (A) and the body of water surrounding the collection container.

3. A method in accordance with the claim 2, characterized in that the vertical force applied to the dam or weir (K) comprises a floating force.

4. A method in accordance with the claim 3, characterized in that the flotation force is composed of two components having the same direction, one of the components is determined by a volume of liquid displaced from the collection compartment (A) and the other component is determined by a volume of liquid displaced in the body of water that surrounds the collection container.

5. The method according to any of claims 2 to 4, characterized in that the vertical force applied to the dam or foaming weir (K) comprises the force which is the resultant of two hydrostatic forces directed oppositely acting on a generator member. force having a force transmitting connection with the dam or foaming weir (K), one of the opposite directed hydrostatic forces is determined by a surface provided on the force generating member and located in the collection compartment (A) and the another is determined by a thrust surface provided on the force generating member and placed in the body of water surrounding the collection container.

6. The method according to any of claims 1 to 5, characterized in that it discharges a layer of supernatant in the collection compartment (A) through a discharge opening which communicates with the collection compartment.

7. The method in accordance with the claim 6, characterized in that it discharges the supernatant layer by means of displacement of a liquid taken from the body of water surrounding the collection container and introduced into the lower portion of the collection compartment.

8. The method in accordance with the claim 7, characterized in that the dam or foaming weir (K) is sealingly coupled with an overlying cover of the collection container when the supernatant layer is being discharged.

9. The method according to any of claims 2 to 8, characterized in that it controls the elevation of the underlying part of the collection container in the body of water by means of floating bodies connected to the underlying part and placed in the body of water surrounding to the collection container.

10. The method according to claim 9, characterized in that it increases the weight of the floating bodies with the increase of the elevation of the underlying part in the collection container in the body of water by coupling volumes of water delimited from the body of water to the bodies floating to make the water volumes accompany the movements of the floating bodies in the body of water.

11. The method according to any of claims 1 to 10, characterized in that the material flowing over the foaming dam (K) in the collection compartment (A) is diverted downwards into the collection container by means of a barrier flow that extends down into the collection compartment.

12. An apparatus for foaming a floating surface layer of a body of water, particularly a surface layer comprising a floating contaminant, such as oil, comprising a collection container which is submersible in a body of water and defines a collection compartment (A) having a top part including a foaming dam (K), which forms an inlet towards the upper end of the collection compartment (A), and means for discharging the water from the collection compartment (A), characterized because the dam or foamed dump (K) moves vertically in relation to the lower part of the collection container.

13. The apparatus according to claim 12, characterized in that means are provided for controlling the elevation of the foaming dam (K) of the water body depending on the difference in pressure or hydrostatic head between the interior of the collection compartment (A) and the outer side of the collection container.

14. The apparatus according to claim 12 or 13, characterized by a cover mounted on the collection container and on the collection compartment (A), the foaming dam (K) is attachable as a seal with the cover to close the collection compartment (A) up.

15. The apparatus according to any of claims 12 to 15, characterized in that the foaming dam (K) comprises a first floating body, at least a portion of which is adapted to displace liquid in the collection compartment (A).

16. The apparatus according to claim 15, characterized in that the first floating body is adapted to displace liquid both in the collection compartment (A) and in the body of water surrounding the collection container.

17. The apparatus according to any of claims 13 to 16, characterized in that the upper part of the collection container moves vertically in relation to the lower part together with the foaming dam (K).

18. The apparatus according to any of claims 12 to 17, characterized by a force generating member, which is connected to the foaming dam (K) and has two opposingly facing thrust surfaces, one of which is located within the collection container and the other of which is located on the outside of the collection container.

19. The apparatus according to claim 18, characterized in that the side wall of the collection container is flexible on at least a portion of the height of the collection container and because the collection container contracts vertically due to the radial contraction of the side wall under the action of a difference in water pressure on the pushing surfaces.

20. The apparatus according to any of claims 12 to 19, characterized in that the collection container collapses vertically in the form of an accordion.

21. The apparatus according to any of claims 12 to 20, characterized by a deflection member in the collection compartment (A) for the downward deflection of liquid flowing over the foaming dam (K) from the surrounding body of water to the collection compartment (A).

22. The apparatus according to claim 21, characterized in that the deflection member is supported by a second floating body which moves vertically independently of the foaming dam (K) and is adapted to be supported by the liquid in the collection compartment (TO) .

23. The apparatus according to any of claims 12 to 22, characterized in that the foaming dam (K) extends over at least the largest portion of the circumference of the collection container.

24. The apparatus according to claims 22 and 23, characterized in that the second floating body delimits a peripheral affluent zone (R) between the foaming dam (K) and the second floating body and a stabilizing zone (S) on the far side of the second floating body seen from the foaming dam.

25. The apparatus according to claim 14 and any of claims 15-24, characterized in that the cover is provided with a discharge opening for liquid in the collection compartment (A).

26. The apparatus according to any of claims 12 to 25, characterized in that the means for discharging water from the collection compartment comprises a reversible pump.

27. The apparatus according to any of claims 12 to 26, characterized by a plurality of external floating bodies, which are connected to the lower part of the collection container and adapted to support the collection container in the body of water, the bodies Floats are horizontally separated from the collection container.

28. The apparatus according to claim 27, characterized in that the external floating bodies are provided with compartments for coupling volumes of water of the body of water with them.

29. The apparatus according to any of claims 12 to 28, characterized in that the additional floating bodies coupled for the foaming dam (K) and operating to apply an additional upward floatation force to the foaming dam (K) in response at a sudden rise in the water level around the collection compartment (A).