SE505131C2 - Device and method for skimming oil layer from surface of water - Google Patents

Abstract

The lower cylindrical collection compartment (11) has an upper sliding telescopic portion (13) supported by a buoyant ring (15) which also forms the overflow weir crest (K). The lower part of the compartment (11) is supported by inverted closed cylinder floats (26) containing a buoyant material (27). An oil entry over the weir (K) is created by a tethered buoyant ring (25,23) and conical skirt (23). Water is discharged from the bottom of the collection compartment (A) by a pump (18). An annular plate (19) and cover (21) close the crest inlet when the collection chamber sinks to its maximum depth.

Description

The device schematically shown in Figs. 1 and 2 comprises a receiving vessel 11, the side wall of which is formed by a lower part 12 and an upper part 13, telescopically arranged therein, which at the bottom has an outwardly directed, towards the inside of the lower part sealing flange 14 and which at the top has an annular floating body 15. The receiving vessel 11 has a bottom wall 16 with an opening 17 through which water formed by the vessel 11 can be pumped into and out of the receiving space A by means of To The receiving vessel 11 also belongs to a lid plate 19 with a fixed relative to the sub- The elements 19A connecting opening 20. The lid plate 19 is the part 12 and the bottom wall 16. the lid plate with these parts is marked with simple lines in Figs. 1-3.

A collecting container 21, not shown in more detail, is sealingly connected to the lid plate 19 in such a way that an inlet part 21A of the container lies in the middle over the opening 20 in the lid plate. The collecting container 21 can be constituted by a liquid tubular "tank" of film or cloth material and serves in the manner described below as a receiver for oil transferred from the receiving vessel 11. The container 21 seals against the lid plate with a sealing ring 22 surrounding the opening 20.

Furthermore, the receiving vessel 11 includes a substantially concentric annular floating body 23 arranged inside the floating body 15 and with it a downwardly directed, likewise annular "skirt" 24.

This "skirt", which is shown to be truncated conical with the small end downwards but which may also have a different shape, may be made with a certain elasticity.

The float body 23 is connected to the float body 15 by means of a number of bands or other flexible connecting means 25, so that it can move relatively unhindered up and down relative to the float body 15. Liquid can pass through the annular space, denoted by R, between float body the pairs 15 and 23 without obstruction of the connecting means 25, since these cover only a small part of this gap. 10 15 20 25 30 35 505 131 _3- In addition to the above-described receiving vessel 11 with associated parts, the receiving device has a number, for example three, floating bodies evenly distributed around the receiving vessel, a piece placed outside the receiving vessel, hereinafter referred to as stabilizing bodies and denoted by 26, which are fixed relative to the lower part 12 of the receiving vessel. These stabilizing bodies 26 have such a lifting force in the water that they project a little above the water surface in the equilibrium position shown in Fig. 1, where the receiving vessel 11 is substantially completely filled with water. Seen from above in Figs. 1-3, there is between the stabilizing bodies 26 a free flow passage between the receiving vessel 11 and the mass of water surrounding the receiving device.

Each stabilizing body 26 has the shape of an upside-down can, the upper part of which, closest to the bottom of the can, houses a floating block 27 of a light material, eg cellular plastic, while the lower part is open. The stabilizing body is designed and arranged in such a way that the space B under the floating block 27 is filled with water when the receiving device is "launched". A non-return valve device (not shown) in the stabilizing body facilitates the water filling of the said space by releasing residual air but closes when this space is pressurized.

When the device is to be used for oil uptake, it is immersed in the body of water from the surface of which oil is to be taken up. In Fig. 1 the device is shown idle, namely in a position where the receiving vessel 11 has been filled with water through the bottom opening 17 and the floating body 15 on the upper part 13 of the receiving vessel has been arranged sealingly against the lid plate 19.

In this position, the pump 18 can be started to pump water downwards out of the receiving vessel 11 through the bottom opening 17.

The pumping out causes the water surface in the receiving vessel to sink so that a water sink is formed inside the floating body 15, ie. the water level will be lower inside the floating body 15 than outside it. 505 131 10 15 20 25 30 35 _ 4 _ The level difference between the liquid in the receiving vessel 11 and the liquid surrounding the receiving vessel which thus arises has an effect on the upper part 13 of the receiving vessel in two ways.

First, the lifting force on the floating body 15 decreases somewhat, since the volume of liquid displaced by the floating body decreases in correspondence with the level difference. The part of the lifting force that is due to immersion of a part of the floating body in the liquid in the receiving vessel decreases due to the level lowering.

Second, the hydrostatic pressure on the top of the top flange 14 will be greater than the hydrostatic pressure on the bottom so that a downward resultant force will affect the flange.

The result is that the upper part 13 of the receiving vessel 11 is displaced downwards relative to its lower part 12. Although the lifting force on the part of the floating body 15 which is immersed in the body of water outside the upper part of the floating body then increases slightly, comes in a certain position the floating body 15 to come below the surface of that body of water, so that the surface layer of oil or oil and water on the surrounding body of water will flow into the receiving vessel 11 over the overflow edge K formed by the upper side of the floating body 15.

The liquid, oil and water which in this way flows over the floating body 15 will be deflected downwards in the receiving space A by the inner floating body 23 with the skirt 24. The flow velocity will then decrease rapidly due to the flow cross section increasing, ie. the downward movement of the liquid will be gradually slowed down and the lighter oil may pass under the lower edge of the skirt 24 and collect on the surface in the space S which the floating body 23 with the skirt 24 delimits.

This is shown in Fig. 2. Oil can of course also collect in the annular space R between the floating bodies 15 and 23. The space S inside the floating body 23 with the skirt 24 constitutes a stabilization zone where the oil can be layered without disturbance from the liquid flowing in radially over the floating body 15.

The pumping out of water from the collecting vessel 11 and the thereby reduced amount of water in it means that the total weight of the water-filled collecting device decreases.

As a result, the stabilizing bodies 26 lift the entire pick-up device to a slightly higher level. However, this lifting is counteracted by the fact that the volumes of water in the lower part B of the stabilizing bodies 26 remain interconnected with them and must therefore follow upwards and thus will act as extra weights.

The interaction between the forces acting in this way partly on the vertically easily movable upper part 13 of the collecting vessel 11, partly on the collecting device as a whole gives a sensitive and rapid self-regulation of the height of the floating body 15 and the overflow edge K and thus a compliant adjustment of the liquid inflow in the receiving vessel for the pumping out. If at a certain moment the inflow into the receiving vessel is too fast in relation to the pumping out, the level difference (or, more precisely, the hydrostatic pressure difference) between the liquid in the receiving vessel and the surrounding liquid will decrease, the floating body 15 moving upwards and limiting the inflow. If, instead, the pumping is too fast in relation to the inflow, the floating body 15 will correspondingly move downwards to increase the inflow.

The force-release in the vertical direction of the easily movable upper part 13 with the overflow edge K from the very slow-moving collecting device otherwise with the volume of water accommodated in the collecting vessel 11 and the stabilizing bodies 26 means that the height of the overflow edge K is very self-regulating. of level changes in the surrounding water mass and in the liquid surface in the collecting vessel. 505 131 10 15 20 25 30 35 _6- After a while, the pump 18 is reversed to pump water from below into the receiving vessel 11. The floating bodies 15 and 23 will then be placed against the underside of the lid plate 19.

The floating body 15 acts as a shut-off valve between the interior of the receiving vessel 11 and the surrounding body of water.

The increased amount of water in the receiving vessel means that the entire receiving device moves downwards in the body of water, but after a certain downward movement, continued downward movement is counteracted by the lifting force on the stabilizing bodies 26, which of course follow the movement. The top layer of the receiving vessel, i.e. the oil layer in the space S inside the float body 23 with the skirt 24 is pressed out into the collecting container 21 floating on the surrounding body of water through the opening of the lid plate 20 and the inlet part 21A of the container with the sealing ring 22. This is illustrated in Fig. 3. the top layer of a displacing the expulsion of the light collecting container 21 by introducing heavier liquid into the receiving space A can take place in a single, continuously occurring moment. However, it can also take place intermittently or in several successive steps by interrupting the introduction of the displacing liquid from time to time.

During the interruption or rest periods, when thus no significant flow to or from the intake space A occurs, oil droplets or oil lumps in the intake compartment can go up undisturbed towards the surface of the space S.

After the transfer of the oil to the collecting container 21 has been completed, the pump 18 can be reversed again and the process described above repeated. Thereby, the lid plate 19 and thus also the intake part 21A of the container 21 will again assume the elevated position shown in Fig. 2, so that backflow of the contents of the container 21 through the opening 20 of the lid plate is avoided.

The changeover from the accumulation of oil in the receiving vessel 11 shown in Fig. 2 to the transfer of the accumulated oil shown in Fig. 3 to the collecting container 21 and the transfer back to the accumulation can also take place in different ways. and with various aids. For example, the height of the accumulated oil layer can be determined on the basis of the power consumption of the motor 18 driven by the pump 18, whereby switching to the transfer position in Fig. 3 can take place automatically when a certain layer thickness has been reached. The switching back to the accumulation mode in Fig. 2 can also take place automatically depending on the power consumption of the pump motor.

Figs. 1-3 are intended to illustrate the principles of the method according to the invention and the device according to the invention rather than to show a preferred embodiment of the invention. It should be emphasized, however, that within the scope of the invention it is possible to deviate from the representation in these figures. For example, the transfer of the oil (or the liquid contaminant of another kind to be taken up) can take place more or less continuously by means of a separate pump device whose intake is in the layer of accumulated oil. Furthermore, with respect to the height and consequently with respect to the volume variable receiving vessel 11, it does not, of course, have to be cylindrical or composed of two separate parts as in Figs. 1-3.

Figs. 4-7 schematically show an example of an embodiment of the receiving device according to the invention, wherein Figs. 4-6 show the device in operating positions corresponding to the operating positions in Figs. 1-3, while Fig. 7 shows the device seen from above.

The pick-up device shown in Figs. 4-7 corresponds in its main features to the pick-up device shown in Figs. 1-3, both in terms of the basic structure and the principle of operation.

The receiving vessel 31 with the receiving space A is in this case designed as a construction which is accordion-likely collapsible in height. The side wall 32 is formed of a flexible but substantially inextensible fabric or film material and is laid around a number of rigid circular rings 33, for example of plastic or light metal.

In the extended position as shown in the figures, these rings are at a distance from each other, but when disassembling the device they can lie next to each other or even one inside the other. The lower ring 33 is connected to a bottom plate 34 which has an opening 35 and a pump device 36 placed therein. On the upper ring 33 sits an annular floating body 37, which forms the overflow edge K and corresponds to the floating body 15 shown in Fig. 1-3.

Inside the upper part of the receiving vessel 31 and substantially concentrically therewith and with the floating body 37 there is an annular floating body 38 with a "skirt" 39 hanging therefrom corresponding to the floating body 23 resp. dress 24 in Fig. 1-3.

The skirt 39 is similar to the receiving vessel 31 a collapsible structure, which is formed of a flexible but substantially inextensible cloth or film material laid around a number of rigid rings 40. The floating body 38 is also here connected to the floating body 37 or the top of the rings 33 so that it can move freely up and down in relation to the floating body 37 but is kept substantially concentric with it at all times. The space between the floating bodies 37 and 38 and the space inside the floating body 38 with the skirt 39 are also here denoted by R resp. S.

As in Figs. 1-3, a lid plate 41 with an opening 42 is arranged in a fixed position relative to the bottom plate 34.

More specifically, the bottom plate 34 and the lid plate 41 are releasably attached to six circumferentially evenly distributed vertical tubes 43. Inside these tubes the floating body 37 and the upper part of the side wall 32 of the receiving vessel 31, and thus the floating body 38 with the skirt 39, can move. up and down.

The tubes 43 support three stabilizing bodies 44 in pairs (corresponding to the stabilizing bodies 26 in Figs. 1-3) while transmitting three pairs of radially projecting upper and lower horizontal brackets 45. As can be seen from Fig. 7, the stabilizing bodies 44 are evenly distributed. circumferentially around the receiving vessel 10 15 20 25 30 35 505 131 _ 9 _ 31 and placed at a radial distance outside it. The outer ends of the brackets 45 in each pair of brackets are releasably attached to a vertical tube 46. Around the upper part of the tube 46 the stabilizing body 44 is arranged.

The stabilizing bodies 44 are designed in a similar manner to the receiving vessel 31 as a vertically collapsible construction of a side wall 47 of flexible fabric or film material and a number of round rigid rings 48. The upper part of the space delimited by the side wall 47 is filled by a floating block 49 of, for example, cellular plastic, while the part of this space located below the floating block is intended to be filled with water during the work of the receiving device. In order to keep the side wall extended, the lower ring 48 is then releasably fixed to the tube 46.

At the upper end of each pipe 46 is a non-return valve 50, which allows air in the space under the floating block to escape upwards when this space is to be filled with water but which closes when a negative pressure arises in this space, so that water outflow from the space is prevented. The water filling and venting can take place via the pipe 46 as marked by arrows in Fig. 4.

In the same way as in Figs. 1-3, a collecting container 51 is sealingly connected to the lid plate 41 in such a way that an inlet part 51A of the container lies in the middle over the opening 42, which is surrounded by a sealing ring 52 on the container.

The device in Figs. 4-7 operates in substantially the manner described above in connection with Figs. 1-3. However, a certain difference lies in the fact that in the cylindrical design shown of the receiving vessel 31 there is no differential pressure surface corresponding to that provided by the opposite pressure surfaces on the flange 14 in Figs. 1-3. Instead, a pulling force on the float body 37 will be provided because the pressure difference across the flexible side wall 32 of the receiving vessel causes the side wall to deform inwardly, thereby pulling the rings 33 against each other so that the entire receiving vessel cone - treated vertically. If desired, however, a differential pressure surface can be achieved by making the receiving vessel narrower at the top than at the bottom.

As can be seen from Figs. 4-7, the receiving device according to the invention can be designed as a very light, quickly assembled and detachable, easily transported construction. It can also be made cheaply. It is therefore economically realistic to manufacture the device in large numbers and place the devices in such a way that they can be transported to any conceivable intervention site in a short time and made ready for operation in a very short time. The versatile inflow into the receiving vessel and the rapid separation of the lighter material in the receiving vessel provide high separation capacity.

In the embodiment described above, the height position of the overflow edge K is self-regulating mainly under the influence of three different forces, namely gravity, a hydrostatic lifting force and a hydrostatic compressive force.

The gravity of the collecting vessel from the collecting device in general, and then in particular the liquid volume, which is vertically disengaged in this absorbed upper part, constantly strives to move the upper part and thus the overflow edge K downwards.

The lifting force on the upper part, on the other hand, strives to move the upper part and thus the overflow edge K upwards.

The lifting force is composed of two vertical components, namely a component with which the liquid in the collecting vessel contributes and a component with which the liquid in the surrounding water mass contributes.

In the condition shown in Figs. 1 and 4, when at each level the hydrostatic pressure in the collecting vessel is the same as the hydrostatic pressure in the surrounding body of water, the sum of the two lifting components is equal to gravity plus 10 15 20 25 30 35 505 131 _11 .. the possible force with which the floating body 15 resp. 23 is pressed against the lid plate.

When the hydrostatic pressure in the receiving vessel is less than the hydrostatic pressure in the surrounding body of water, a downward force determined by the pressure difference also acts as the third force.

In Figs. 1-3 this third force is applied while conveying the flange 14. In Figs. 4-7 the force is achieved by pressing the side wall of the receiving vessel inwards between the rings 33 and thereby stringing together horizontally so that the whole vessel is contracted vertically.

However, it is within the scope of the invention to achieve a similar self-regulation in other ways. For example, the latter force, the third force, can be dispensed with by omitting the differential pressure surface, so that only a lifting force varying depending on the pressure difference between the receiving vessel and the surrounding water mass has an effect.

Another possibility is to replace the lifting force, or supplement it, with an upward force acting on the upper part of the receiving vessel and thus on the overflow edge K, for example a spring force. Another possibility is to apply such a downward force, ie. a force cooperating with gravity.

Other, purely constructive modifications are also possible. The annular shape shown on the overflow edge and the inner deflection means constituted by the floating body 23, 38 with the skirt 24, 39 is very advantageous but not necessary. It is thus possible to allow the inflow into the receiving space to take place over an overflow edge K which does not extend around the entire receiving vessel but only over that part of its circumference (but preferably the greater part thereof), whereby the deflection means may be limited to a corresponding part of the circumference .

Claims (26)

505 131 10 15 20 25 30 35 -_12- Patent claim A method of separating from a body of water a surface layer, in particular a surface layer containing oil or other material floating on the water, wherein in the body of water a collecting vessel (11, 31) is placed with a collecting space (A) bounded upwards by an overflow edge ( K), and the collection space is filled with water, a water sink is formed and maintained in the collection space (A), the overflow edge (K) is caused to assume a flood position relative to the surface layer, so that it can flow over the overflow edge into the water sink, characterized in that the overflow edge (K) is arranged vertically movable in relation to a part (16, 34) of the receiving vessel (11, 31) located at a lower level in the water mass, and the height position of the overflow edge (K) in the water mass is regulated by applying to the overflow edge a vertical force whose magnitude varies with the difference in hydrostatic pressure between the receiving space (A) and the water mass surrounding the receiving vessel (11, 31). Method according to claim 1, characterized in that the vertical force applied to the overflow edge (K) comprises a hydrostatic lifting force. A method according to claim 2, characterized in that the lifting force is composed of two uniform components, one component being determined by a volume of liquid displaced in the receiving space (A) and the other component being determined by a volume of liquid displaced in the surrounding water mass. A method according to any one of claims 1-3, characterized in that the vertical force applied to the overflow edge (K) comprises a force constituting the resultant of two opposing hydrostatic forces on a force generating force-transmitting connection with the overflow edge (K). One force (14, 32), one force being determined by a pressure surface located inside the receiving space (A) on the force generating means and the other force being determined by one in that receiving vessel (11, 32). 31) surrounding pressure mass located pressure surface on the force generating means. Method according to claim 1, characterized in that an overlying layer in the receiving space (A) is removed through an outlet opening (20, 42) communicating therewith. Method according to claim 5, characterized in that the overlying layer is removed by means of a displacing liquid which is introduced into the lower part of the receiving space (A) from the water mass surrounding the receiving vessel (11, 31). Method according to Claim 6, characterized in that during the removal of the overlying layer, the overflow edge (K) is caused to abut sealingly against an overlying lid (19, 41) on the receiving vessel (11, 31). Method according to any one of claims 1-7, characterized in that the height position in the water mass for said lower part (16, 34) of the receiving vessel (11, 31) is regulated by means of floating bodies (26 arranged in the vessel surrounding the water mass arranged in this vessel). , 44). Method according to claims 1-8, characterized in that the weight of the floating bodies (26, 44) is increased with increasing height position in the water mass for said lower part (16, 34) of the receiving vessel (11, 31) by entering the water mass, volumes of water delimited by the floating bodies are connected to the floating bodies to follow their movements in the body of water. Method according to one of Claims 1 to 9, characterized in that material flowing into the receiving space (A) over the overflow edge (K) is deflected downwards in the receiving vessel (11, 31) by a flow barrier (23, 24, 38) projecting into the receiving space. , 39). Asos 151 10 15 20 25 30 35 _14- Device for separating a surface layer from a body of water, in particular for absorbing oil or other material floating on the water, which device comprises a receiving vessel (11, 31) forming a water-lowerable, receiving space (A) with an overflow edge (K ) forming an inlet to the upper part of the receiving space (A), and means (17,18, the receiving space (A), 35,36) for removing water from characterized in that the overflow edge relative to a lower part (11, 31) and that the height (14,15, 31,37) height position of the overflow edge (K) in the water mass in dependent (K) is movable in vertical direction in (16, 34) of the receiving vessel are arranged to regulate the difference in hydrostatic pressure between the receiving space ( A) and the outside of the receiving vessel (11, 31). Device according to Claim 11, characterized by a lid (19, 41) arranged on the receiving vessel (11, 31) above the receiving space (A), against which the overflow edge (K) can be sealingly arranged to close the receiving space (A) upwards. Device according to Claim 11 or 12, characterized in that the overflow edge (K) is arranged on a first floating body (15, 37), at least a part of which is arranged to displace liquid in the receiving space (A). Device according to claim 13, characterized in that the first floating body (15, 37) is arranged to displace liquid both in the receiving space (A) and in a body of water surrounding a receiving vessel (11, 31). Device according to one of Claims 11 to 14, characterized in that the overflow edge (K) is arranged on an upper part (13) of the receiving vessel (11, 31), which upper part is vertically movable. in relation to said lower part (16, 34) of the receiving vessel. Device according to one of Claims 11 to 15, characterized by a pressure generating means (14, 32) connected to the overflow edge (K) having two oppositely facing pressure surfaces, one of which is located inside the receiving vessel (11). , 31), while the other is arranged on the outside of the receiving vessel. Device according to claim 16, characterized in that the side wall (32) of the receiving vessel (31) is flexible over at least a part of the height of the receiving vessel and that the receiving vessel is contractile in height by constriction of the side wall (32) in horizontal direction under the action of a pressure difference between the pressure surfaces. Device according to one of Claims 11 to 17, characterized in that the receiving vessel (31) is accordion-like collapsible in height. Device according to one of Claims 11 to 18, characterized by a means (23, 24, 38, 39) arranged in the receiving space (A) for deflecting downwardly liquid flowing into the receiving space (A) from the surrounding body of water over overflow edge (K). Device according to claim 19, characterized in that the deflection means (23, 24, 38, 39) is supported by a second floating body (23, 38), which is vertically movable independently of the overflow edge (K) and arranged to be supported by liquid in the recording chamber (A). Device according to one of Claims 11 to 20, characterized in that the overflow edge (K) extends over at least the greater part of the circumference of the receiving vessel (11, 31). 505 131 10 15 20 25 _ 16 _ Device according to Claims 20 and 21, characterized in that the second floating body (23, 38) delimits on the one hand a peripheral inflow zone (R) located between the overflow edge (K) and the second floating body, and on the other hand a view seen from the overflow edge (K) the stabilization zone (R) located on the far side of the second buoyancy body. Device according to Claim 12 and one of Claims 13 to 22, characterized by a outlet opening (20, 42) for liquid in the receiving space (A) arranged in the cover (19, 41). Device according to any one of claims 11-23, characterized in that said means for removing water from the receiving space comprises a reversible pump (18, 36). Device according to any one of claims 11-24, characterized by a plurality of outer floating bodies (26, 44) which are connected to said lower part (16, 34) of the receiving vessel (11, 31) and arranged to support the receiving vessel in a floating position with the said lower part thereof immersed in the water mass and thereby lying on the water mass at a horizontal distance from the receiving vessel. Device according to Claim 25, characterized in that the outer floating bodies (26, 44) have spaces for connecting water volumes contained in the body of water to them.