SYSTEM FOR PICKING UP OIL FROM THE WATER

Abstract: The object of the invention is a system for removing oil from the surface of water, comprising a rotating gripping element (4) fitted in a casing (2) through which water polluted by oil flows, and a means (6) for removing the material collected in the gripping members (5). A tunnel structure (3) is fitted inside the casing (2), its inner diameter being about the same size as the greatest outer diameter of the gripping element (4). The gripping element (4) is coaxial with the tunnel structure (2). The tunnel structure (3) provides an effective direction of the water flow through it and the gripping members (5).

Description: System for picking up oil from the water The object of the invention is a system for removing oil from the surface of water, comprising a rotating gripping element which is fitted to a casing through which oil-polluted water flows, and a means for recovering the substance gathered in the gripping members. Patent publications FI 70443 and PCT/FI90/00086 discribe drum-like, rotating systems that collect oil. These systems are intended to be installed in vessels so that the speed of travel of the vessel provides a water flow and enhances the oil collection of the system. The efficiency of the system is considerably reduced when running at low speeds. Application publication FI 914650, for example, describes an oil collection arrangement used in connection with a vessel, comprising rotating brush wheels fitted to a casing. Water polluted by oil flows through the small holes in the front wall of the casing to the brush wheel compartment, laterally through the holes in the wheels, and through a hole in the partition wall of the casing to an adjacent receiver. Thus, the water does not flow very effectively through the brush wheels; therefore, the collection result is not very good. The purpose of the invention is to provide a system in which guiding oil-polluted water through the brush wheels and the adhesion of oil to the bristles would be as effective as possible. This is achieved by the system according to the invention the main characteristics of which are showed in the characterising clause of claim 1. The system according to the invention is generally used in connection with an apparatus moving in water, more generally in connection with a vessel, but it can also be self-sufficient and move by its own power. Inside an outer casing is fitted a tunnel structure with an inner diameter of about the same size as the outer diameter of the gripping element where the gripping members of the element are longest. The gripping element is coaxial with the tunnel structure and preferably located partly inside the tunnel structure. The tunnel structure with its gripping elements can form a 0°-90° angle with the longitudinal axis of the vessel pulling the system. The angle is preferably 0° or close to it but it also works throughout the said 0°-90° range of the angle. Securing and supporting the system to the vessel is adapted to said angle. The gripping element according to the invention is preferably a brush drum comprising a drum, bristle rings being spaced on its periphery in the direction of the periphery. The bristle length of the bristle rings preferably grows from the front end towards the back of the brush drum with respect to the direction of movement of the vessel. The brush drum rotates by the driving power of its own motor. When the vessel moves, the water coming towards it is effectively directed to the tunnel structure and strained between the bristles, leaving the oil pollution of the water in the bristles of the brush drum. A comb member is arranged to press the oil out of the bristles and to transfer it to an oil container or, alternatively, to an elevator that turns around the tunnel structure and the pivoting support above it, the elevator again transferring the collected oil to the vessel. Instead of the elevator, a more expensive pump solution is used with greater amounts of oil. To enhance the water flow through the tunnel structure, a propeller can be made to rotate simultaneously with the brush drum. The propeller receives its driving power from its own motor. At least the rearward bristle ring of the brush drum has an outer diameter, i.e., as measured from the ends of the bristles, of the same measure as the inner diameter of the surrounding tunnel structure and it constitutes the last break for the water flowing through to capture any oil that still remains in the water. At the front end of the brush drum, the outer diameter of the bristle rings preferably increases backwards, whereby a conical envelope surface is formed, smoothening and helping the guiding of the water flow to the tunnel structure. The front end of the brush drum preferably projects slightly from the tunnel structure, for example, so that three bristle rings are outside the tunnel and three inside, the last two rings extending to the inner surface of the tunnel. The whole brush drum can also be inside the tunnel structure. The number of the bristle rings can vary according to the conditions. The number of rings can be as small as three or four but preferably from five to seven. The brush drum is easy to replace. A conical element may be placed in front of the brush drum to enhance directing the water flow inside the tunnel. The tunnel structure with its brush drums, the propeller and both motors are attached to a beam arrangement from which they can be detached for replacement or maintenance. The jacket of the tunnel can be open, for example, where the comb member is situated. There are often various kinds of debris mixed with the oil on the surface of the water, disturbing the operation of the system when they meet the bristles. To solve this problem the system comprises a debris collecting grate rotating about 270°, throwing the problematic solids into the oil collecting container through the comb member. To enhance the water flow, an additional propeller can be fitted in the water outlet of the casing. In the following, the invention is described in detail with the aid of preferred embodiments with reference to the schematic drawings in which: Fig. 1 shows the system according to the invention in its operating position, attached to the side of a vessel, Fig. 2 is a top view of a preferred embodiment of the system, Fig. 3 is a side view of another preferred embodiment of the system, Fig. 4 is a back view of a further preferred embodiment, Fig. 5 is a cross-section of the embodiment according to Fig. 4 as viewed from the back, Fig. 6 shows the embodiment of Figs. 4 and 5 as viewed from the outer side, Figs. 7a to 7d show another embodiment of the invention; Figs. 7a and 7b from the back and Figs. 7c and 7d from the front, Fig. 8 is a side view of the embodiment according to Figs. 7, Fig. 9 is a back view of another embodiment of the system, Fig. 10 shows schematically the alternative angle positions of the system with respect to the longitudinal axis of the pulling vessel. 7/00209 Fig. 1 shows the system according to the invention as attached to the one side of the vessel in a position where the axis of the tunnel structure is parallel with the longitudinal axis of the vessel. The fixing of the system and that of the oil boom to the vessel is illustrated in the Figures. In the Figures, the same reference numbers are used to refer to the corresponding parts. Fig. 2 is a top view of one system according to a preferred embodiment. The tunnel structure 3 is placed inside the outer casing 2. The brush drum 4 is placed inside the casing 2 and partly inside the tunnel 3, the bristle rings 5 being placed on its peripheral surface in the direction of the periphery. The direction of movement of the system as fitted to the vessel is in the direction of the arrow, i.e., to the right. The forward bristle ring of the brush drum comprises the shortest bristles, the next one comprises slightly longer bristles, and the third visible bristle ring comprises the longest bristles. The circumferential surfaces of the bristle rings thus constitute a conical envelope surface facilitating directing the water flow to tunnel 2 through the bristle rings. The bristles of the rearward bristle ring extend to the lining of tunnel structure 3. Part of the water polluted by the oil flows through all the bristle rings, part only flows through two and part only through one bristle ring. Practically speaking, no water is allowed to pass the bristle rings without going through them, so the oil adheres to the bristles. The comb member 6 presses the oil out of the bristles and transfers it to the oil container or directly to the elevator which carries the oil to the vessel. The hydraulic motor 7 rotates the brush drum. The motor 7 and the brush drum are replaceably attached to the casing 2 with the aid of beam framework 8. Fig. 3 shows another system according to a preferred embodiment as viewed from the front. This embodiment is the same as the former, with the exception of propeller 9 which is placed coaxially to the tunnel structure and the brush drum at the rear of the tunnel structure, the propeller enhancing the water flow through the tunnel structure. The propeller is an efficient accessory which essentially increases the water flow through the system in low velocities of the vessel in particular. Propeller 9 uses another hydraulic motor 7'. Fig. 4 shows another preferred embodiment as viewed from the back. The system comprises propeller 9 driven by motor 7'. The motor is attached to casing 2 by beam framework 8. Oil elevator 10 is arranged to circle the lower periphery of tunnel structure 3 and rotatable roll 11. Elevator 10 is fitted inside the casing structure 12. In the embodiment presented, the elevator comprises transfer elements 13 made of bristles. Comb member 14 or similar is fitted in conjunction with the elevator next to the rotatable roll 1 1 to transfer the oil conveyed by the elevator to the oil container or similar of the vessel. Fig. 5 shows the cross-section of the system illustrated in Fig. 4 as viewed from the back. It shows comb member 6 and the bottom 15 of the oil container. Fig. 6 shows the system according to Figs. 4 and 5 as viewed from the outer side. The conveyor bottom 16 of elevator 10 is grate-like in order to filter from the oil the solids which are among the polluted oil. The elevator is fitted beside propeller 9, in front of it. The transfer members 13 of the elevator and casing structure 12 are installed to travel in the space between tunnel structure 3 and casing 2. Regarding brush drum 4, only the front part protruding from the tunnel structure is visible, comprising three bristle rings. There can be several bristle rings inside the tunnel structure 2. The figure does not show the driving motor T of the propeller. Figs. 7a-7d show one preferred embodiment with a rotating debris collecting grate 17 added to it, and a conical structure placed in front of the system. Figs. 7a and 7b show the system as viewed from the back, as a cross-section and not cut, and Figs. 7c and 7d show it from the front, correspondingly. The debris collecting grate 17 is arranged to turn 270 . The water outlet is marked with number 18. The conical structure is marked with number 19. Its location in the longitudinal direction of the vessel is illustrated in Fig. 8. Fig. 8 shows the embodiment according to Figs. 7a to 7d as viewed from the side. The water level is marked with the letters WL. The conical structure 19 is installed immediately in front of the system, so it effectively directs the water flow inside the tunnel structure through bristle rings 5. The bristle rings of the brush drum 4 all have the same outer diameter. The brush drum is inside tunnel structure 3 the width of two bristle rings 5, and in front of it the width of four bristle rings. Propeller 9 is fitted immediately behind the brush drum. Fig. 9 shows an advantageous embodiment of the system as viewed from the back. A small propeller has been added next to the water outlet to enhance the water flow through the system. Fig. 10 shows alternative angle positions of the system with respect to the pulling vessel. The new feature in the system according to the invention is that it comprises a tunnel structure coaxial with the brush drum 4 which at least partly surrounds the brush drum and comprises an inner diameter which is about the same as the greatest outer diameter of the bristle rings of the brush drum. This arrangement can be used to effectively direct the water flow to the tunnel structure and through it, so the water polluted by oil is brushed through the bristle rings and the polluted oil effectively adheres to the bristles. Guiding of water flow to the tunnel structure is enhanced by a propeller fitted at the end of the tunnel structure. By giving the bristles of the bristle rings different lengths so that the outer peripheries of the rings form a conical surface, the guiding of the water flow into the tunnel is enhanced. By installing the elevator known per se in connection with the system, it has been possible to replace a more expensive pump solution with a cheaper solution. However, the capacity of the elevator is only sufficient when the amounts of oil are smaller. The location of the brush drum with respect to the tunnel structure, i.e., how far inside the tunnel it is installed, is determined on the basis of experience. The angle position of the system with respect to the longitudinal axis of the pulling vessel is selected in accordance with the conditions. Generally, the tunnel structure and the brush drum are installed parallel to the vessel but a fairly small angle does not essentially affect directing the water inside the tunnel. The system works according to the idea of the invention even with a larger angle up to about 90° . The system can also be self-supporting so that it moves under the effect of the propeller providing the water flow. This very advantageous solution can be used in small operational areas. Such a practical system can be quickly taken into use when small oil spills occur in waterways in industrial regions. It is also clear to those skilled in the art that the amount of bristles per unit of surface in the bristle rings, the mutual distance of the bristle rings, and the length of the bristles are selected according to the conditions and experience. It is also clear that the gripping members of the brush drum can be other gripping members rather than bristles, such as a tassel or tassels of a synthetic substance to which the oil easily adheres and from which it is easy to remove by the compression of the comb member.

Claims: CLAIMS 1. A system (1) for removing oil from the surface of water, comprising a rotating gripping element (4) for collecting oil, the element being fitted to a casing (2) through which oil-polluted water flows, and a means (6) for transferring the material gathered in the gripping members into a receiver, characterised in that a tunnel structure (3) is fitted inside the casing (2), the inner diameter of the tunnel structure being about the same size as the greatest outer diameter of the gripping element (4), and that the gripping element (4) is coaxial with the tunnel structure (2). 2. A system according to Claim 1 , characterised in that the gripping members are bristles (5) and the gripping element is a brush drum (4). 3. A system according to Claim 2, characterised in that the front end of the brush element (4) with respect to the direction of travel of the vessel projects from the tunnel structure (3). 4. A system according to Claim 2, characterised in that the brush element (4) is installed entirely inside the tunnel structure (3). 5. A system according to any of Claims 2 to 4, characterised in that a propeller (9) is fitted behind the brush element (4) and inside the tunnel structure (3) with respect to the direction of travel of the vessel to enhance the water flow through the tunnel structure (3). 6. A system according to Claim 5, characterised in that the brush element (4) and the propeller (9) are both driven by their own motors. 7. A system according to any of Claims 2 to 6, characterised in that the brush element consists of a drum (4), bristle rings (5) being spaced on the envelope surface of the drum in the direction of its periphery. 8. A system according to Claim 7, characterised in that the diameter of the bristle rings (5) increases from the first ring to the last rings with respect to the direction of travel of the system, so that a conical envelope surface is formed. 9. A system according to Claim 7 or 8, characterised in that the diameter of at least the rearmost, preferably the two rearmost bristle rings (5) is about the same size as the inner diameter of the surrounding tunnel (3). 10. A system according to Claim 7 or 8, characterised in that the outer diameter of all the bristle rings (5) is about the same size as the inner diameter of the surrounding tunnel (3). 11. A system according to any of Claims 2 to 10, characterised in that a conical structure (19) is fitted in front of the brush element (4), coaxially with it, the bottom dimension of the conical structure preferably being smaller than the cross section of the tunnel structure (3). 12. A system according to any of Claims 2 to 11 , characterised in that a belt conveyor (10) for the collected material is fitted immediately behind the brush rings (5), circumventing, from below, the tunnel (3) surrounding the brush drum (4) and, from above, the pivoted roll (11), and that a comb member (6) is installed to transfer the material gathered in the bristles (5) to the belt conveyor (10) from where it is transferred to the vessel. 13. A system according to any of the preceding Claims, characterised in that the longitudinal axis of the tunnel structure (3) constitutes an angle with the longitudinal axis of the vehicle pulling the system, the angle being between 0 and 90°, preferably between 0° and 50° . 14. A system according to Claim 13, characterised in that the angle is between 0° and 30°, preferably close to 0° .

Inventors: MAEKINEN MIRJA TUULIKKI, MAEKINEN, MIRJA, TUULIKKI
Applicants: MAEKINEN MIRJA TUULIKKI, ORREBO BUSINESS AB OY, MAEKINEN, MIRJA, TUULIKKI, OY ORREBO BUSINESS AB
Application year: 1997
Main classification: E02D15
IPC codes: E02B15