WO2014012183A1

WO2014012183A1 - Device for recovery of an immiscible contaminant from a surface of a liquid

Info

Publication number: WO2014012183A1
Application number: PCT/CA2013/050557
Authority: WO
Inventors: Brian GIFFORD
Original assignee: Gifford Brian
Priority date: 2012-07-18
Filing date: 2013-07-18
Publication date: 2014-01-23

Abstract

A collection device recovers a contaminant, for example oil, dispersed on another liquid, for example water, which is immiscible with the contaminant. The collection device includes a housing supporting a gang of augers therein at an upward incline from an inlet opening at one end to a collection area at the other end of the housing. The augers are rotated such that the contaminant and the liquid are drawn into the inlet opening and conveyed towards the collection area where separation by gravity occurs. Liquid separated from the contaminant in the collection area is urged downwardly through an outlet passage by the incoming flow from the augers while the concentration of contaminant in the collection area increases for subsequent retrieval.

Description

DEVICE FOR RECOVERY OF AN IM ISCIBLE CONTAMINANT FROM A SURFACE OF A LIQUID

This application claims priority benefits from U.S. provisional application Serial No. 61/673,085, filed July 18, 2012.

FIELD OF THE INVENTION

The present invention relates to a collection device for recovery of a contaminant dispersed in a layer on a surface of a liquid immiscible with the contaminant, for example a device for recovery of surface floating hydrocarbons from a body of water, and more particularly the present invention relates of a collection device which uses an auger to transfer the contaminant to an enclosed collection area while permitting a return flow of liquid separated from the contaminant.

BACKGROUND

Removing hydrocarbons from water is a well known problem encountered when cleaning up oil spills for example. Because hydrocarbons are immiscible with water and a significant portion is more buoyant than water, hydrocarbons tend to form a layer on the surface of a body of water such that various collection devices involve some form of skimming the surface of the body of water.

United States Patents 3,618,768 by Brown, 4,976,855 by Virtanen and 7,297,259 by Zori Garcia disclose oil spill collection devices generally involving an open screw auger supported across the surface of a body of water for conveying oil at the surface to one end of the screw auger for collection. In general no effective means are provided for separating oil and water such that considerable water may be collected with the oil. Furthermore, sludge deposits can readily deposit on the auger such that the auger is no longer effective at conveying the oil to a collection area.

US Patent 5,160,638 by Petkovic discloses an oil spill cleaning screw for conveying oil from a surface of a liquid to a collecting area. To prevent excess liquid in being collected with the oil, perforations are provided in the flighting of the screw. The device is not well suited for various conditions however because depending upon the viscosity or conditions encountered, excess liquid may be collected if the perforations are too small and excess oil may escape if the perforations are too large.

US Patent 3,447,683 by Luce Jr. disclosed a device for separation of impurities from the exposed surface of a liquid body. The device comprises an enclosed housing operating in a closed loop and which is not readily portable for use on site as in the common occurrence of oil spills on a body of water. An auger is provided having a tapering diameter in the direction of conveyance in an effort to permit escape of fluid being collected with oil, however the close proximity of a surrounding auger tube may result in emulsification of the impurities with the liquid which complicates the separation and recovery of the impurities. Furthermore no means are provided for removing sludge deposits which may collect on the flighting of the auger.

US Patent 4,151 ,081 by Bolli et al. discloses a process for recovery of a contaminant on the surface of another liquid which also uses an auger in one embodiment which is closely surrounded by an auger tube along two opposing sides. The auger remains open to an outlet passage along the bottom side thereof. Liquid is intended to pass through the housing in a continuous flow along the outlet passage across the bottom of the auger, however due to the open access between the bottom of the horizontal auger oil may be readily drawn with the flow to the outlet rather than being recaptured.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a collection device for recovery of a contaminant dispersed in a layer on a surface of a liquid immiscible with the contaminant, the device comprising:

a housing comprising two side walls which are upright and laterally spaced apart from one another so as to span in a longitudinal direction between a first end and a second end of the housing, an inlet opening defined between the two side walls adjacent the first end of the housing, and an end wall joined between the two side walls adjacent the second end of the housing;

at least one auger supported on the housing between the two side walls for rotation about a respective longitudinal axis extending generally in the longitudinal direction of the housing from the inlet opening at the first end of the housing towards a collection area between the two side walls at the second end of the housing; and

an outlet passage in communication from the collection area below said at least one auger to an outlet opening adjacent the first end of the housing;

said at least one auger being arranged for rotation in a working direction such that the contaminant and the liquid are arranged to be conveyed into the inlet opening in the longitudinal direction towards the collection area at the second end of the housing and such that liquid separated from the contaminant in the collection area at the second end of the housing is directed by the outlet passage outwardly through the outlet opening.

By locating the inlet and outlet openings in proximity to one another, the device is well suited for batch treatment of fluid and contaminant within a contained area. Typically an area affected by an oil spill can be surrounded with containment booms arranged to be buoyantly supported at the surface of the liquid to fully surround the area to be treated as defined by the booms about the perimeter thereof. The housing can then be coupled to the containment booms such that the inlet opening and the outlet opening each communicate with the area to be treated for recycling the liquid through the device until substantially all contaminant is collected in collection area at second end of housing of the collection device.

Preferably a bottom wall is joined between the two side walls to extend in the longitudinal direction between the first and second ends of the housing. In this instance, the one or more augers are preferably spaced above the bottom wall at the first end of the housing to define the outlet opening below the inlet opening and to define the outlet passage extending in the longitudinal direction between the two side walls from the collection area to the outlet opening.

Preferably a baffle member spans between the two side walls from the first end of the housing towards the second end of the housing below the one or more augers so as to define the outlet passage therebelow between the baffle member and the bottom wall. The baffle member is preferably substantially horizontal in orientation and extends more than half a length of the one or more augers from the first end towards the second end of the housing.

Preferably the two side walls include respective curved portions at opposing sides of the housing in close proximity to and having a mating profile in relation to the one or more augers.

The collection device may further include a drive assembly arranged for driving rotation of the one or more augers which is coupled to the auger or augers adjacent the second end of the housing.

According to a second aspect of the present invention there is provided a collection device for recovery of a contaminant dispersed in a layer on a surface of a liquid immiscible with the contaminant, the device comprising:

an outlet passage in communication from the collection area below said at least one auger to an outlet opening;

said at least one auger being arranged for rotation in a working direction such that the contaminant and the liquid are arranged to be conveyed into the inlet opening in the longitudinal direction towards the collection area at the second end of the housing and such that liquid separated from the contaminant in the collection area at the second end of the housing is directed by the outlet passage outwardly through the outlet opening; and

said at least one auger extending at an upward inclination from the inlet opening at the first end of the housing towards the second end of the housing.

In this instance the area of the auger flighting at the inlet opening at the first end may be fully submerged relative to the liquid and contaminant while a majority of the area of the auger flighting at the second end of the housing extends above the surface of the liquid and contaminant. The auger or augers thus extend upwardly over the collection area at the second end of the housing so that contaminant is free to fall downwardly from the augers into the collection area instead of being churned into an emulsion with the liquid by the auger at the collection area. The continued operation of the augers instead acts to continue to concentrate and collect the contaminant in the collection area as the concentrated contaminant continues to urge separated liquid downwardly and outwardly from the outlet opening of the housing and the liquid continues to be recycled through the collection device.

According to a third aspect of the present invention there is provided a collection device for recovery of a contaminant dispersed in a layer on a surface of a liquid immiscible with the contaminant, the device comprising:

a gang of augers supported on the housing between the two side walls for rotation about respective longitudinal axes extending in the longitudinal direction of the housing from the inlet opening at the first end of the housing towards a collection area between the two side walls at the second end of the housing; and

an outlet passage in communication from the collection area below the augers to an outlet opening of the housing;

the augers being arranged for rotation in a working direction such that the contaminant and the liquid are arranged to be conveyed into the inlet opening in the longitudinal direction towards the collection area at the second end of the housing and such that liquid separated from the contaminant in the collection area at the second end of the housing is directed by the outlet passage outwardly through the outlet opening.

The arrangement of a gang of augers in proximity to one another allows the augers to interact with one another to convey larger solid portions of the contaminant. Furthermore, the interaction between adjacent augers prevents large deposits, for example as may be found in oily sludge, from collecting on the augers and interfering with auger operation as the augers effectively scrape the deposits from one another to maintain optimal operation despite the nature of the contaminant.

The augers are preferably supported for rotation about respective longitudinal axes which lie in a common plane with one another.

Preferably the augers are also supported in overlapping arrangement with one another such that the augers are arranged to mesh with one another as they are rotated in the working direction.

Each auger may include a flight which is wound helically from the first end towards the second end of the housing in a direction which is opposite to a flight of an adjacent one of the augers. In this instance, each auger is operable in working direction to rotate in direction which is opposite to said adjacent one of the augers.

The two side walls may include respective curved portions in close proximity to and having a mating profile in relation to respective outermost ones of the augers at opposing sides of the housing.

Some embodiments of the invention will now be described in conjunction with the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a partly sectional side elevational view of the collection device.

Figure 2 is a front elevational view of the first end of the housing of the collection device.

Figure 3 is a rear elevational view of the second end of the housing of the collection device.

Figure 4 is a top plan view of the collection device.

Figure 5 is a schematic representation of the collection device in combination with a containment boom.

In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION

Referring to the accompanying figures, there is illustrated a collection device generally indicated by reference numeral 10. The device 10 is particularly suited for use in recovery of a contaminant disbursed in a layer on a surface of a liquid immiscible with the contaminant, for example hydrocarbon disbursed in a thin layer on the surface of a body of water as occurs in an oil spill. The device 10 is arranged for recovery of the contaminant by collecting the contaminant in a collection area as contaminant and liquid are cycled through the device.

The device 10 is typically suited for use with a containment boom structure 12 of the type comprising elongate barrier members which are buoyantly supported on the surface of the liquid to penetrate down into the liquid from the surface greater than the depth of the contaminant on the surface. The boom thus fully surrounds and contains the contaminant in a treatment area defined by the boom which extends in a closed loop about the full perimeter thereof.

The device 10 includes a housing 16 arranged to be buoyantly supported in the body of water. The housing is coupled to the boom structure such that an inlet opening 36 and an outlet opening 38 of the housing communicate with the treatment area surrounded by the boom structure. Liquid and contaminant are cycled from the treatment area into the inlet opening and through the housing where the contaminant is permitted to separate by rising over the liquid so that the liquid can be returned to the treatment area through the outlet opening. Even if some contaminant is returned with some liquid to the treatment area, the contaminant is typically recycled back through the housing with continued operation of the collection device such that contaminant continues to accumulate within the collection area of the housing until substantially all contaminant is collected and recovered by the device 10.

The housing 16 is elongate in a longitudinal direction from a first end 22 at the front end of the housing to an opposing second end 24 at the rear end of the housing. The housing includes two opposed side walls 26 which are generally upright and extend generally in the longitudinal direction substantially parallel to one another along the full length of the housing between the opposing first and second ends and across a full height of the housing. An end wall 28 is joined between the two side walls at the second end of the housing to extend downwardly at an outward inclination from the top end to the bottom end thereof.

A bottom wall 30 extends generally horizontally between the two side walls and longitudinally a full length of the housing between the first and second ends so as to be joined with the end wall at the second end.

A baffle member 32 spans horizontally between the two side walls and in the longitudinal direction from the first end at an intermediate location part-way between the top and bottom ends towards the opposing second end of the housing. The baffle member only extends longitudinally part-way from the first end to the second end such that a collection area 34 is defined in the housing adjacent the second end between the inner end of the baffle member and the end wall 28.

The baffle member effectively defines an inlet passage extending longitudinally between the two side wall and above the baffle member from an inlet opening 36 at the first end between the side walls towards the collection area at the opposing end. The baffle member further defines an outlet passage extending in a longitudinal direction below the baffle member and above the bottom wall from the collection area to an outlet opening 38 at the first end of the housing below the inlet opening. The outlet opening is bound between the two side walls, the baffle member thereabove and the bottom wall therebelow at the first end of the housing.

A pair of deflectors 39 are supported at the first end of the housing on opposing sides of the inlet and outlet openings. The deflectors each comprise an upright plate member having an inner surface extend outwardly from the housing in the longitudinal direction at an outward inclination away from the opposing deflector. The deflectors thus define a mouth opening at the first end of the housing which diverges outwardly to become wider towards respective forward edges which are arranged to be coupled to respective sections of the containment boom respectively.

A gang of augers 40 are supported rotatably on the housing to extend generally longitudinally within the inlet passage from the inlet opening to the collection area. Each auger 40 comprises a shaft 42 defining a longitudinal axis of rotation of the auger and a helical flighting 44 wound helically from the first end to the second end of each auger shaft 42. The augers 40 are supported such that the axis of rotation are parallel and spaced apart from one another in a generally common plane which is inclined upwardly and rearwardly from the first end to the second end of the housing.

Each of the augers 40 has a continuous diameter along the length thereof and a continuous pitch of the flighting. The augers are supported such that the full cross sectional area or diameter of the flighting is arranged to be fully submerged relative to the liquid and contaminant thereon adjacent to the inlet opening. Alternatively, the augers are supported substantially fully above the surface of the contaminant on the body of water overtop of the collection area adjacent the second end of the housing. In this manner, the contaminant being conveyed by the auger is permitted to fall from the auger to the collection area at the second end of the housing.

In the illustrated embodiment, three augers are shown, however more or fewer augers may be used as desired. Typically the augers are arranged in side by side relationship so as to be altering from augers of a first configuration 46 and augers of a second configuration 48. In the illustrated embodiment, the two outermost augers are arranged in the first configuration while the innermost, central auger between the two outermost ones is arranged in the second configuration. Accordingly, each auger of first configuration is adjacent an auger of second configuration and vice versa. In the first configuration the auger includes a flighting which is wound about the shaft from the first end to the second end in a first helical direction. In the second configuration, the flighting of the auger is wound from the first end to the second end in an opposing second helical direction.

The augers are positioned adjacent one another in sufficiently close proximity such that the flighting of each auger overlaps the flighting of adjacent augers in a meshing configuration. More particularly, the outer edge of the flighting of one auger is arranged to project radially into the space between sections of flighting of the adjacent auger by positioning the axes of rotation of the augers in closer proximity to one another than the overall diameter of the flightings of the augers when all of the augers have an identical diameter flighting and an identical pitch of flighting.

The augers are each supported on the housing for rotation at the first end by a suitable first bearing support 49 on a cross member 50 connected between the two opposing side walls at the first end of the housing. The cross member spans laterally across the first end of the housing at the location of the front edge of the baffle member 32 so as to be located between the inlet opening thereabove and the outlet opening therebelow. Second bearing supports 52 rotatably support the opposing second ends of the augers on the end wall at the rear of the housing respectively.

A drive assembly is provided externally of the housing at the second end in the form of gears supported on respective ones of the auger shafts in meshing engagement with one another. The gears mesh with one another such that the augers of first configuration rotate together in a first direction of rotation while the augers of second configuration counter-rotate in an opposing second direction. A suitable motor provides an input rotation to any one of the auger shafts such that the remaining augers similarly rotate by meshing engagement of the gears 54.

Each side wall includes a curved portion 56 in alignment with the respective one of the two outermost augers. At the curved portion, the side wall has a profile which mates with and is concentric with the respective auger by having an internal radius closely matching the outer radius of the flighting of the auger to permit the side walls to be located in close proximity to the outer sides of the two outermost augers. The close proximity encourages a substantially uniform flow of liquid and contaminant through the inlet passage when the augers span the full lateral width of the inlet passage.

In operation, containment booms are deployed about an oil spill to fully surround the contaminant on the surface of the liquid body of water. The housing is then coupled to the boom structure such that the inlet and outlet openings communicate with the contained treatment area. Rotating the augers causes the augers to urge an inflow of liquid and contaminant floating thereon into the housing through the in!et opening from the first end towards the containment area at the second end.

The buoyancy of the contaminant relative to the liquid body of water permits the water to separate from the oil. The separated water is urged downwardly by the accumulating oil deposits at the collection area to be subsequently directed by the end wall and bottom wall back towards the first end of the housing. The separated liquid is thus effectively pushed downwardly by the accumulating oil to generate an outflow of liquid down and outwardly through the outward passage from the collection area through the outlet opening where the fluid is returned to the treatment area.

Even if some oil is removed through the outlet opening, the device continues to operate until the oil is again collected with another inflow of liquid into the inlet opening. Periodically collected oil or sludge may be removed from the collection area to an auxiliary containment area 58 in proximity thereto where the collected contaminant can be disposed of. Periodic transfer of collected contaminant from the collection area of the housing to the auxiliary containment area may be accomplished by auger, siphoning tube, pumping or any other suitable configuration.

Many variations to the preferred embodiment described above without departing from the functional benefits of the present invention.

In further embodiments the shape of the housing can be varied such that the side walls extend generally in the longitudinal direction as straight walls or any other shape which does not necessarily conform to the shape of the augers. The function of the side walls is only to contain the contaminant being collected as it is conveyed from the inlet end to the collection area. Similarly, the end wall at the collection area may comprise any suitable form of boundary which encloses the collection area at the second end of the housing for containing the collected contaminant therein.

When multiple augers are spaced apart from one another, additional intermediate walls can also be provided which also span in the longitudinal direction between adjacent ones of the augers to assist in containing the contaminant as it is conveyed in the longitudinal direction towards the collection area.

The baffle member which spans longitudinally to define the inlet passage thereabove and the outlet passage therebelow may also be changed in shape and orientation as compared to the preferred embodiment described above. For example, the baffle may be curved to conform to the profile of the augers thereabove and may be horizontal or inclined with the augers in the longitudinal direction. The length of the baffle members can also be varied.

In further embodiments, one or more augers may be provided within the housing which can be rotated in any combination with the only requirement being that the contaminant is conveyed by the augers from the inlet at the first end of the housing to the collection area at the second end of the housing. Accordingly, all of the augers may have flighting oriented in the same direction so that the augers are rotated in the same direction, or any one or more of the augers may have flighting oriented in an opposing helical direction such that the auger with opposed flighting is rotated in the reverse orientation to maintain all augers conveying contaminant towards the collection area.

In yet further embodiments, the pitch and/or diameter of the auger flighting can also be varied along the length of the augers in the longitudinal direction. Accordingly, the longitudinal axes of rotation of the augers may be parallel, may converge with one another, or may diverge with one another between opposing ends of the housing. The inclination may also be varied such that the augers are oriented at a steep upward inclination towards the collection area, or may be nearer to horizontal. Though less preferable, a downwardly inclined auger from in the inlet opening to the collection area may also provide some satisfactory results.

While in the illustrated embodiment the inlet opening of the housing is located at the perimeter of a boom structure, the entire housing may be centrally located within an area bounded by a boom structure. The housing may also function satisfactorily by simply being supported in open water without a boom structure.

The housing can be supported in the body of water by its own flotation, or by attachment to any other suitable structure such as a rig or platform structure, or another flotation structure such as being suspended from a boat for example.

In yet further arrangements, the outlet passage from the collection area may simply involve the bottom of the collection area being open to the body of water within which the housing is supported provided that the side walls and the end walls which provide the boundary about the collection area are supported to a sufficient depth within the body of water within which they are suspended that an adequate amount of contaminant can be contained within the collection area.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

Claims

CLAIMS:

1. A collection device for recovery of a contaminant dispersed in a layer on a surface of a liquid immiscible with the contaminant, the device comprising:

2. The device according to Claim 1 further comprising a bottom wall joined between the two side walls to extend in the longitudinal direction between the first and second ends of the housing, wherein said at least one auger is spaced above the bottom wall at the first end of the housing to define the outlet opening below the inlet opening and to define the outlet passage extending in the longitudinal direction between the two side walls from the collection area to the outlet opening.

3. The device according to Claim 2 further comprising a baffle member spanning between the two side walls from the first end of the housing towards the second end of the housing below said at least one auger so as to define the outlet passage therebelow between the baffle member and the bottom wall.

4. The device according to Claim 3 wherein the baffle member is substantially horizontal in orientation.

5. The device according to either one of Claims 3 or 4 wherein the baffle member extends more than half a length of said at least one auger from the first end towards the second end of the housing.

6. The device according to any one of Claims 1 through 5 wherein said at least one auger extends at an upward inclination from the inlet opening at the first end of the housing towards the second end of the housing.

7. The device according to any one of Claims 1 through 6 wherein the two side walls include respective curved portions in close proximity to and having a mating profile in relation to said at least one auger at opposing sides of the housing.

8. The device according to any one of Claims 1 through 7 in combination with a containment boom arranged to be supported at the surface of the liquid to fully surround a treatment area, the housing being coupled to containment boom such that the inlet opening and the outlet opening each communicate with the treatment area.

9. The device according to any one of Claims 1 through 8 further comprising a drive assembly arranged for driving rotation of said at least one auger and being coupled to said at least one auger adjacent the second end of the housing.

10. The device according to any one of Claims 1 through 9 wherein said at least one auger comprises a gang of augers supported for rotation about respective longitudinal axes which are parallel to one another.

11. The device according to Claim 10 wherein the augers are supported for rotation about respective longitudinal axes which lie in a common plane with one another.

12. The device according to either one of Claims 10 or 11 wherein the augers are supported in overlapping arrangement with one another such that the augers are arranged to mesh with one another as they are rotated in the working direction.

13. The device according to any one of Claims 10 through 12 wherein each auger includes a flight which is wound helically from the first end towards the second end of the housing in a direction which is opposite to a flight of an adjacent one of the augers and wherein each auger is operable in working direction to rotate in direction which is opposite to said adjacent one of the augers.

14. The device according to any one of Claims 10 through 13 wherein the two side walls include respective curved portions in close proximity to and having a mating profile in relation to respective outermost ones of the augers at opposing sides of the housing.

15. A collection device for recovery of a contaminant dispersed in a layer on a surface of a liquid immiscible with the contaminant, the device comprising:

a housing comprising two side walls which are upright and laterally spaced apart from one another so as to span in a longitudinal direction between a first end and a second end of the housing, an inlet opening defined between the two side walls adjacent the first end of the housing, and an end wall joined between the two side walls adjacent the second end of the housing; at least one auger supported on the housing between the two side walls for rotation about a respective longitudinal axis extending generally in the longitudinal direction of the housing from the inlet opening at the first end of the housing towards a collection area between the two side walls at the second end of the housing; and

16. A collection device for recovery of a contaminant dispersed in a layer on a surface of a liquid immiscible with the contaminant, the device comprising:

a gang of augers supported on the housing between the two side walls for rotation about respective longitudinal axes extending in the longitudinal direction of the housing from the inlet opening at the first end of the housing towards a collection area between the two side walls at the second end of the housing; and an outlet passage in communication from the collection area below the augers to an outlet opening of the housing;

17. The device according to Claim 16 wherein the augers are supported for rotation about respective longitudinal axes which lie in a common plane with one another.

18. The device according to either one of Claims 16 or 17 wherein the augers are supported in overlapping arrangement with one another such that the augers are arranged to mesh with one another as they are rotated in the working direction.

19. The device according to any one of Claims 16 through 18 wherein each auger includes a flight which is wound helically from the first end towards the second end of the housing in a direction which is opposite to a flight of an adjacent one of the augers and wherein each auger is operable in working direction to rotate in direction which is opposite to said adjacent one of the augers.

20. The device according to any one of Claims 16 through 19 wherein the two side walls include respective curved portions in close proximity to and having a mating profile in relation to respective outermost ones of the augers at opposing sides of the housing.