Oil spill cleanup system

#Much effort has been expended toward the development of systems for collecting oil both inshore and offshore. Results from these efforts have not been particularly encouraging. Major problems have been encountered in oil escapement from boom-skimmer arrangements due to the effects of waves as well as currents and due to structural strength and stability difficulties. The various structurally oriented troubles that have confronted investigators conducting sea tests of prototype equipment are actually easier to rectify for they are within the realm of accomplishment. The oil escapement problems caused principally by wind, waves, and currents on the other hand are a severe challenge, because the solution requires a significant advancement in the state of the art of oil spill clean-up technology. Accordingly, the present invention provides several basic departures from other concepts which have been utilized in the development of various equipment for cleaning oil spills.

#Tests conducted with prior art skimming vessel devices have shown that oil can escape boom-skimmer arrangements while influenced by the orbital water particle motion associated with modest 3 foot waves in negligible currents and that rigid skimming vessels allow oil to escape because of a lack of conformance of the skimmer with respect to the wave profile. Based on such tests, the skimming system configuration of the present invention was developed with a skimming vessel which is articulated along its length with regard to the sides of the vessel and/or its bottom baffles, thereby providing conformance superior to prior art skimming vessels by moving like a roller coaster over the waves. When presented with oil in a towing tank, the skimmer of this invention, because of its excellent conformance characteristics, collected in excess of 95% of the oil presented at a forward velocity of 1.7 feet per second and a wave height-to-length ratio of 1/9, where by comparison a conventional skimmer would be ineffective.

#Secondly, the present invention provides a means for containing oil at a current velocity magnitude twice that for a conventional oil skimmer. Oil can be contained with the device of this invention with less than 5% throughput loss at a velocity of 2 feet per second where conventional concentrating skimmers are limited to a maximum velocity of 1.25 feet per second. The basic principle involved is to slow down the effective current inside the concentration area while at the same time allowing the oil to enter horizontally. In the process of this invention, the oil is retained on or quite near the surface of the water within the confines of the concentrator for skimming. The virtually horizontal path of the oil into the concentrator is important in the instance of heavy weathered oils and emulsions because any forces tending to push the oil downward will result in oil sweeping under and past the skimming vessel prior to re-surfacing.

#FIGS. 1 and 2 compare features of the present invention with the prior art;

#FIGS. 3-5 are plan, sectional and front views, respectively, of one embodiment of the invention;

#FIGS. 6 and 7 are top and sectional views, respectively, of another embodiment of the invention;

#FIGS. 1 and 2 compare significant features of the present invention with the prior art. FIG. 1 shows the advantages of articulation. It is apparent that the mouth of the articulated skimmer does not rise above the surface of the water. On the other hand, the mouth of the prior art skimmer does periodically rise above the level of the water so that oil is missed. FIG. 2 discloses the advantages of providing a forward baffle which permits horizontal entry of the oil into the skimmer while still functioning to dampen wave action. Among the prior art devices, one device pushes the oil down before it can rise into the skimmer so that, especially with heavy oils, much does not rise in time to be collected, and the other device, a conventional floating box skimmer, allows waves to enter the skimmer with a resultant loss in efficiency.

#The apparatus of a first embodiment, as depicted in FIGS. 3-5, includes skimmer structure articulated to allow wave conformance during towing or dynamic positioning, an optional wind tunnel to thicken the oil lens at the suction area and a sump design that permits suction at the top of the oil lens without differential movement between the suction pipe and supporting ceiling and the oil lens. The skimmer may be one component of a sweep system having as other components diversionary booms, towing vessels and a pumping-storage vessel. Also, the skimmer may be considered as a primary separation means and secondary separation may be combined with the pumping-storage equipment.

#The skimner of FIGS. 3-5 may be compared with other conventional means of skimming in various ways. Thus, the present device, which can be unmanned, has a means of positioning the suction at the top of the oil lens and minimizing differential movement between the oil lens and the suction pipe. Conventional discrete skimmers cannot maintain the weir at the oil level in waves. The overflow sluice gate design of a conventional floating box skimmer as shown in FIG. 2 allows a significant amount of water to enter and requires a man on board to adjust the gate. By removal of excess water at selected intervals along the skimmer of the present invention, the entrance flow is reduced thereby minimizing the total amount of fluid to be processed. In the floating box skimmer excess water is released only at a single rearward location, giving rise to local turbulence problems.