CA1090715A

CA1090715A - Oil spill recovery system

Info

Publication number: CA1090715A
Application number: CA334,400A
Authority: CA
Inventors: Frank F.A. Bedford
Original assignee: Bedford Frank F A
Current assignee: Bedford Frank F A
Priority date: 1979-08-24
Filing date: 1979-08-24
Publication date: 1980-12-02

Abstract

Abstract of the Disclosure This invention is an oil spill recovery system comprising a skimming and sluicing weir mounted on a barge containment vessel. The construction of the weir with a slop reservoir; and of the barge with a separating tank, storage tank and pumping system, permit a clean pick-up and containment of the oil spill. The weir is connected to the barge in a substantially rigid fore and aft direction but has vertical movement relative to the barge, controlled by a deck winch. The barge has good oil storage capacity which can be increased by using a trailer barge for large spills or spills in critical areas.

Description

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This invention relates to an oil spill recovery system that picks up surface pollutant through a skimming and sluicing action as it moves forward through the polluted area. It does so in a thorough and efficient manner.

A calculated shaped weir is attached through a special framework to a barge containment vessel. This vessel is designed with a separating tank, a storage tank, a buoyancy compartment, an engine room and a cofferdam.
These compartments together with a pumping system are controlled from a conning deck house.

Heretofore, in the field of oil spill recovery, it has been known to provide a vessel with a closed top, open bottom tank in its mid-portion. Hydraulic means such as a plurality of water jets or mechanîcal means in the form of a paddle wheel force the oil polluted water down along the sides of the inverted tank and thence into its open bottom. There is little or no turbu-lence inside the tank and the oil, having less density, rises to the ceiling of the tank. From here it can be pumped out into collector units. The downwardly directed water jets are shown in Canadian Patent 1,025,778. The paddle wheel intake with adjustable lip is shown in Canadian Patent 1,001,567.

., It has not been known to provide a skimming weir with a sluicing action which has an enclosed reservoir to receive slop and to have this fluid discharged by controlled pump flow into a primary tank. Here, the slop is separated by natural specific gravity. The upper layer is transferred into a barge storage tank and/or into a trailer barge.
':' It has not been known to provide a line blow-back to clear extraneous floating matter that may create a blockage in the line system.

The closed in hull of this invention does not require underside openings for the purpose of drainage or oil separation.

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A preferred embodi~ent of the invention is illustrated in the accompanying drawings wherein:

Figure 1 is a plan view of the weir, Figure 2 is a section taken on the line II-II of Figure 1, Figure 3 is a section taken on the line III-III of Figure 1, Figure 4 is an elevation of the barge and weir, and Figure 5 is a plan view of the barge and weir.

With reference to Figure 1, weir 1 has on its upper forward portion an angled restraining plate 2 which creates an orifice by reason of its spacing from the weir. Between front wall 3 and rear wall 4 there is an enclosed slop reservoir 5. This slop reservoir extends laterally from the mid-portion of the weir into side wings of the weir. The side wings are blanked off as shown at 6. In the slop reservoir 5 are a plurality of strainer boxes 7. These boxes are connected by vertical pipes 8 to a common pipe (not shown) that leads to a deck pump. This pump is shown at 15 in Figure 4. Strainer boxes 7 are provided with holes in their upper and side surfaces. Their under surfaces are closed off with cover plates.
An angled back plate 9 extends around the rear upper surfac,e of the weir.
Fluid pressure acting against this back plate maintains the weir in its correct horizontal attitude. ~rifice defining plate 2 and back plate 9 ~., u are shown more clearly in Figures 2 and 3. The floor of the slop reservoir ~", i5 provided with flood and drain holes 10. Guided roller 11 and support roller 12 give the weir a substantially rigid connection with the barge.
Further stability is given to the weir by a deck winch on the barge that is !
;1 connected to a plurality of lifting lugs at fore and aft locations on the "'1 weir. A pair of these lifting lugs is shown in Figure 3.

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Further to Figure 1, the centre of buoyancy of the weir coincides with the axis of roller 11.

Figure 2 is a section on the line II - II of Figure 1 and shows the configuration of the weir in elevation. The upper surface of the weir has a rounded nose portion that slopes downwardly and rearwardly to the base or floor of the weir. Front wall 3 and rear wall 4 are filled with styrofoam for buoyancy. Between these two walls is the slop reservoir 5. Flood and drain holes 10 are provided in the floor of the reservoir. Spaced from the nose of the weir and in angular relationship to it is a restraining plate 2 that creates an intake orifice for the weir. A sliding adjustment of the restraining plate will vary the size of this orifice. This is critical when skimming off a thick layer or a thin layer of oil. The thickness of the layer determines as well the rate of forward travel through the spill area. Mounted on the rear upper surface of the weir is a back plate 9. It has a slight forward inclination and acts to stabilize the weir and to restrain pick-up overspill. The rounded nose portion of the weir creates a wave uplift pressure in forward travel.
In another embodiment, not shown, the rear wall of the weir has a stepped-up relationship to the front wall.

Figure 3 is a section on the line III - III of Figure 1 and shows a strainer box 7 and its takeoff pipe 8. Support for the strainer boxes and their ,, ', take-off pipes is provided by conventional bracing means between the pipes ; and the upper wall of the weir. The takeoff pipes lead into a common flexible ' pipe that carries the oil slop into the pumping system that is mounted on the barge. For further stability of the weir to the structure shown in Figure 1, ~- strategically secured lifting lugs in pairs is provided. A fore and aft pair of lugs is shown at 13. These lugs are line connected to a deck winch on the barge. This provides a means of incremental raising and lowering , for the weir , for pickup purposes and other functions.

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4~ 715 Figure 4 is an elevation of the barge and weir show;ng the pumping system on the barge and the barge compartments. Intake piping 14 leads to the deck pump 15. The pump discharge is taken by pipe 16 into the separating tank 17. This separating tank is pyramidal or parabolic in shape. The surrounding space above the separating tank and between the partitions constitutes the storage tank 18. There is communication between the two tanks. Oil from the top of the separating tank can be taken off directly by line 19. Top oil in the storage tank is taken off by line 20. The main water discharge from the separating tank is through line 21 and is handled by an auxiliary pump shown at 22 in Figure 5. A relief valve is fitted to line 21 adjacent this pump.

Figure 5 shows the barge and pumping system in plan. In addition to line 20 in the storage tank space there is a longer line 24 that takes out bottom water for aft overside discharge. Auxiliary pump 22 provides overside discharge of separating tank water through line 21. The relief valve for line 21 is shown at 23. Pump 22 also provides a blow back to clear the main intake line of matter extraneous to the oil pollutant. Regulating valves are shown at 25 and 26; and at 27 on the main oil discharge line 19.
Further regulating valves 28 are shown for a suction line 29 that enables the main pump 15 to empty the separating tank of water through an overboard discharge 30. The blow back line is shown at 31. A valve chest for main pump 15 is shown at 32.

It is thus seen that an oil spill can be handled cleanly and efficiently with a skimming and sluicing weir that can be maintained in its correct attitude regardless of weather conditions or fluid intake. The system enables as well the detachment of the weir from the barge and replacing it with one of a different capacity.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An oil skimming and sluicing weir for mounting on a vessel, said weir having a closed front wall, side walls and a rear wall that enclose a slop reservoir with drain holes provided in the bottom of the reservoir, said front wall having a rounded nose in its forward portion, an orifice defining plate mounted above the rounded nose and in angular adjustable relationship thereto, the orifice thus defined providing a controlled intake to the slop reservoir, the mounting for the weir on a vessel maintaining the upper surface of the weir just above the undisturbed surface of the water-borne oil it encounters.

2. The device of claim 1 wherein the rounded nose of the front wall of the weirslopes downwardly and rearwardly to the bottom of the weir to form an obtuse angle with said bottom.

3. The device of claim 1 wherein the mounting for the weir is constrained in a desired attitude by buoyancy forces and mechanical lifting means which compensate for the added weight and pressure against and within the weir of the fluid encountered by the weir.

4. An oil spill recovery system comprising a self-propelled vessel, a skimming and sluicing weir mounted on said vessel, means on the vessel to maintain the upper surface of the weir just above the undisturbed surface of the water-borne oil it encounteres, said weir having a closed front wall with a rounded nose portion, side walls and a rear wall that enclose a slop reservoir with drain holes provided in the bottom of the reservoir, an orifice defining plate mounted above the rounded nose and in angular adjustable relationship thereto providing means to vary the size of the orifice thus defined and discharge means from the weir to the self-propelled vessel.

5. The system of claim 4 wherein the discharge means from the weir to the vessel comprises a piping and pumping system, a separating tank and one or more storage tanks.

6. The system of claim 5 wherein said tanks are in series in accordance with an extended length of the vessel.

7. The system of claim 5 wherein a line blow-back is provided to clear extraneous floating matter from the piping and pumping system by a return flow.

8. The system of claim 5 wherein the pumping system incorporates an auxiliary pump for direct tank discharge from the separating tank.