GB2258825A

GB2258825A - Skimming device for recovering floating oil

Info

Publication number: GB2258825A
Application number: GB9117524A
Authority: GB
Inventors: Ban Mohamed Isa Shaa
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-08-14
Filing date: 1991-08-14
Publication date: 1993-02-24
Also published as: GB9117524D0

Abstract

A device (1) for skimming a fluid from a surface region of another fluid immiscible therewith, having one or more skimming members (10) supported by spaced floats (30) and connected to a sump tank (50) housing a pump for removal of the skimmed fluid through discharge pipe (110). The skimming members (10) have one or more apertures (20) which define fluid inlets through which surface fluids may flow into the tank either under gravity or by the suction of the pump. Floats (60) are provided for supporting the tank. The floats and skimming members are typically made from PVC plastics tubing and connected together using standard fittings (90, 100). In use the device is deployed onto the surface of an oil slick and the floats maintain the skimming members with the slots aligned adjacent the surface oil. Oil is then removed for further processing. <IMAGE>

Description

A SKIMMING DEVICE, IN PARTICULAR FOR RECOVERING WATERBORNE OIL The present invention relates to a device for skimming a fluid from a surface region of another fluid immiscible therewith and in particular, but not exclusively, to a device for recovering oil from a seaborne oil slick.

Surface oils tend to spread easily and readily cover large areas. In the case of a large seaborne oil slick severe environmental damage as well as economic loss may be caused if the slick is not controlled.

Conventional methods of dealing with an oil slick include trapping oil using floaters and then pumping the oil into containers or alternatively employing a large anti-pollution vessel having open rear tanks to trap the oil and allow it to separate from the water and then to pump water out from beneath the oil whilst the oil is dealt with. Alternative means involve treating the oil with chemicals to disperse it. Such means may be expensive, complex or time-consuming to deploy and may require considerable manpower. The use of chemicals is itself likely to cause pollution problems.

The present invention seeks to alleviate the abovementioned problems and to provide a device which skims surface fluids for subsequent recovery storage. The device can be made from inexpensive or readily available materials and can be quickly deployed or arranged to work with the minimum of supervision.

The invention provides a device for skimming a fluid from a surface region of another fluid immiscible therewith, which comprises a conduit defining a skimming member having at least one fluid inlet for skimming surface fluids into the device and at least one fluid outlet for removing skimmed fluids from the device for storage or furthe#r processing and support means for aligning the fluid inlet with a surface fluid to be skimmed.

The support means may comprise one or more floats disposed on or adjacent and extending away from a side region of the skimming member. The skimming member may be elongate and may have a plurality of spaced floats distributed along its length and disposed on both sides of the skimming member. The fluid inlet may be in the form of an aperture or row of apertures each having at least one edge thereof disposed on or adjacent a side region of the skimming member, and more especially an elongate slot or row of slots.

The skimming member may be connected to a sump tank for collecting skimmed fluids at one end thereof such that fluids flowing into the skimming member will flow into the sump tank under gravity. The device may be provided with means for supporting the sump tank during use. The means for supporting the sump tank during use may be one or more floats connected to or integral with the sump tank or connected to one or more skimming members. The device may be provided with a pump for removal of skimmed fluid. The pump may be of the hydraulic or compressed air type preferably is of the vacuum ejection type powered by pressurised fluid supplied by a delivery or feed pipe. The pump may be disposed inside the sump tank and powered from an external power source disposed away from the device.

The device preferably has one or more pairs of skimming members connected to and extending away from peripheral regions of the sump tank and having one or more fluid inlets disposed on one side only of each skimming member for effecting a sideways movement of the device or a rotation of the device about the sump tank due to the flow of fluid into the fluid inlets or the suction of the pump.

Alternatively, a pair of fluid inlets may be provided disposed on opposite side regions of the skimming member. The fluid outlet for removing skimmed fluids from the device for storage or further processing is preferably a fluid discharge pipe connected to the sump tank and which pipe has a valve for regulating-the flow rate of fluid leaving the sump tank thereby regulating the buoyancy of the sump tank or performance of the device.

The skimming member may be connected to the sump tank by a flexible conduit for allowing relative movement of the sump tank and skimming member such that the performance of the skimming member is not upset by changes in the buoyancy of the sump tank.

The device may be provided with heating means for reducing the viscosity of skimmed fluids contained therein.

For example heat may be supplied by a heater disposed within the sump tank thereby aiding removal of fluid from the sump tank.

In use, the device is deployed onto the surface of an oil slick, for example by crane from an oil tanker, and readily floats by itself. Oil or a mixture of oil and seawater flows through the apertures in the skimming members and into the sump tank under gravity. The pump is then activated and fluid is removed from within the tank through the discharge pipe.

Surface fluids continue to flow into the fluid inlets and sump tank under gravity or the suction of the pump, and are extracted upon entering the sump tank by the pump for example, directly into the hold of an oil tanker.

The rate of flow of the fluid being ejected from the device may be regulated when required by regulating the power supplied to the pump or by regulating the tap or throttle on the discharge pipe if provided.

Where fluid inlets are provided on one side only of the device the device will move towards that side due to the flow of fluid into the device. The device may then be deployed to move towards or into an oil slick.

Other modifications are possible within the scope of the invention. For example, several devices could be joined together to form a continuous barrier.

In order that the present invention may be more readily understood, reference will now be made to the accompany drawings in which: figure 1 shows a perspective view of a skimming device in accordance with a first embodiment of the invention suitable for small scale use or demonstration purposes, figure 2 shows a partly sectioned view along line A-A in figure 1, figures 3 and 4 show side and plan views respectively of a second embodiment suitable for large scale use, figure 5 shows a partly sectioned view along line B-B in figure 4, and figure 6 shows a partly sectioned view of a modification of the second embodiment as seen along line C-C in figure 4.

A first embodiment of the device 1 is shown in figures 1 and 2 and comprises a pair of skimming members 10 having laterally extending fluid inlet slots 20, floats 30 for supporting members 10 and aligning the slots 20 with the surface fluids during use and fluid outlets 40 connected to a sump tank 50 containing a pump (not shown). Tank 50 has fluid inlet holes (not shown) disposed in its underneath region for allowing the device to sink to its operating position when first deployed. Parallel spaced floats 60 are disposed on either side of the sump tank 50 for support and stability, and are conveniently connected underneath the innermost pair of floats 30 forming a catamaran type raft as shown in figure 1.

The skimming members 10 and floats 30 and 60 are made from polyvinyl chloride (PVC) pipes. As shown in figures 1 and 2 the floats 30 and 60 are formed using end caps 70 and bulkheads 80 disposed at or adjacent opposite ends of the tubes forming sealed chambers for the required support and buoyancy.

As shown in figure 1 the floats 30 are connected to the skimming members 10 by cross and T-joints 90, 100 formed from standard pipe fittings. The floats 30 extend substantially perpendicularly away from opposite lateral regions of the skimming members 10 for supporting and minimising axial roll of skimming members 10.

The pump (not shown) contained within the sump tank 50 pumps fluid from within the tank through a discharge pipe 110 into one or more storage containers for subsequent processing, for example on an oil tanker.

A 12 volt electrical bilge pump has been found to be adequate for small scale applications, for example a device such as that shown in figures 1 and 2.

The rate of flow of fluid out of sump tank 50 is regulated by a valve (not shown) disposed in the discharge pipe 110 or by electrically regulating the rate of pumping of the pump by any suitable means.

In use, the device is deployed onto the surface of a liquid, for example a waterborne oil slick. The device then sinks to its operating position by allowing air to be expelled from within tank 50 by fluid entering both through holes (not shown) in the bottom of tank 50 and under gravity through slots 20.

The pump is then activated and fluid is pumped out of sump tank 50. Surface oil or water then flows under gravity or by the suction of the pump through slots 20, outlets 40 and into sump tank 50 where it is then pumped out through discharge pipe 110.

Since the sump tank 50 tends to rise when fluid is extracted, the rate of pumping is adjusted such that fluids continue to flow into the device under gravity.

A second embodiment comprising a larger scale device suitable for skimming oil from a seaborne oil slick is shown in figures 3 to 6.

As shown in figures 3 and 4, the device comprises skimming members 10 having spaced elongate and generally rectangular section floats 200 laterally extending through the members 10, a sealed sump tank 50 and flexible conduits 210 for allowing relative movement of members 10 and tank 50. As shown in figure 5, tank 50 has integral buoyancy chambers 220 disposed on opposite lateral regions thereof and a lifting lug 230 on its upper end. The tank 50 houses a hydraulic pump 240 powered by pressurised fluid supplied through feed pipe 250.

The fluids inside tank 50 are extracted through discharge pipe 260 as indicated by the arrow shown in figure 5.

Members 10 and floats 200 are made from any suit able material, for example plastics tubing or wood.

In use, the device is deployed onto the surface of an oil slick by any suitable means, for example by a crane attached to lug 230.

The device immediately floats to its operating position and sump tank 50 fills with oil flowing under gravity through slots 20.

The pump 240 is then activated by providing pressurised fluid, for example, high pressure oil from an adjacent vessel through inlet pipe 250 and oil is extracted from tank 50 through outlet pipe 260 into a suitable container, for example, an oil tanker.

Fluids are extracted from tank 50 at any possible flow rate since corresponding changes in buoyancy of tank 50 due to changes in the flow rate do not affect the performance of the skimming members 10 by virtue of the flexible conduits 210.

Oil or a mixture of oil and seawater is thus recovered into an adjacent container for further processing or separation.

In a modification of the device as shown in figure 6, the floats 200 are disposed slightly below the level of slots 20 to ensure that slots 20 are at the anticipated surface level of the oil for optimum oil skimming performance of skimming members 10.

Modifications are possible within the scope of the invention. For example, slots 20 could be arranged on opposite lateral regions of members 10. Alternatively a single pair of slots 20 could be disposed on diagonally opposite lateral regions of a pair of members 10 so as to effect a rotation of the device about the tank 50 such that the regions of members 10 having slots 20 define the leading edges of members 10. The skimming members 10 may be made from any suitably shaped conduits, for example box section or made from any suitable material, for example metals. The slots 20 could be any suitably shaped aperture or row or series of apertures.

The pump could be any suitable type, for example a pressurised air operated pump or alternatively the pump could be disposed outside or on top of the sump tank 50 or on an adjacent ship or vessel.

Also, a heater could be incorporated in the device for reducing the viscosity of the fluid being pumped to aid the pumping process.

Claims

1. A device for skimming a fluid from a surface region of another fluid immiscible therewith, comprising a conduit defining a skimming member having at least one fluid inlet for skimming surface fluids into the device, at least one fluid outlet for removing skimmed fluids from the device for storage or further processing and support means for aligning the fluid inlet with a surface fluid to be skimmed.

2. A device as claimed in claim 1 wherein the support means comprises at least one float disposed on or adjacent and extending away from a side region of the skimming member.

3. A device as claimed in claim 2 wherein the skimming member is elongate and has a plurality of spaced floats distributed along its length and extending on both sides of the skimming member.

4. A device as claimed in any preceding claim wherein the fluid inlet is an aperture or row of apertures each having at least one edge thereof disposed on or adjacent a side region of the skimming member.

5. A device as claimed in claim 4 wherein the aperture is an elongate slot.

6. A device as claimed in any preceding claim wherein the skimming member is connected to a sump tank for collecting skimmed fluids at one end thereof such that fluids flowing into the skimming member will flow into the sump tank under gravity.

7. A device as claimed in claim 6 wherein means are provided for supporting the sump tank during use.

8. A device as claimed in claim 7 wherein the means for supporting the sump tank during use comprise at least one float connected to or integral with the sump tank or connected to at least one skimming member.

9. A device as claimed in any one of claims 6-8 wherein the fluid outlet for removing skimmed fluids from the device for storage or further processing is a fluid discharge pipe connected to the sump tank, which pipe has a valve for regulating the flow rate of fluid leaving the sump tank, thereby regulating the buoyancy of the sump tank or performance of the device.

10. A device as claimed in any one of claims 6-9 wherein the skimming member is connected to the sump tank by a flexible conduit for allowing relative movement of the sump tank and skimming member such that the performance of the skimming member is not affected by changes in the buoyancy of the sump tank.

11. A device as claimed in any preceding claim wherein there is provided a pump for removal of skimmed fluid.

12. A device as claimed in claim 11 wherein the pump is of the hydraulic or compressed air type.

13. A device as claimed in claim 11 wherein the pump is of the vacuum ejection type powered by pressurised fluid supplied by a feed pipe.

14. A device as claimed in any one of claims 1113 wherein the pump is disposed within a sump tank arranged to collect skimmed fluids from the skimming member and is powered from an external power source disposed away from the device.

15. A device as claimed in claim 14 which device is provided with at least one pair of skimming members connected to and extending away from peripheral regions of the sump tank and having fluid inlets disposed on one side region only of each skimming member for effecting a sideways movement of the device or a rotation of the device about the sump tank, due to the flow of fluid into the fluid inlets or the suction of the pump.

16. A device as claimed in any preceding claim wherein a pair of fluid inlets are provided disposed on opposite side regions of the skimming member.

17. A device as claimed in any preceding claim wherein the device is provided with heating means for reducing the viscosity of skimmed fluids contained therein.

18. A device as claimed in claim 17 wherein the heating means is disposed within a sump tank arranged to collect skimmed fluids from the skimming member, thereby aiding removal of fluid from the sump tank.

19. A device for skimming a fluid from a surface region of another fluid immiscible therewith, substantially as described herein with reference to the accompanying drawings.

20. A barrier comprising a plurality of devices according to any preceding claim joined together to form a continuous barrier.