GB1584095A - Contaminant recovery apparatus and method - Google Patents

Description

(54) CONTAMINANT RECOVERY APPARATUS AND METHOD (71) We, JOHN GEORGE LOWE of 15 Fairview Avenue, Pequannock, New Jersey 07440, United States of America, and ROY IRVING BUTLER of 733 Ridge Road, Kinnelon, New Jersey 07405, United States of America, both citizens of the United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to contaminant recovery apparatus for removing contaminants floating on or near the surface of a contaminated fluid, and contaminant recovery methods using such apparatus.

Oil recovery systems are not new and are extensively used to pick up oil spills and the like, particularly from oceans and inland waterways. Generally, these oil recovery systems utilize a belt or a scraper-type apparatus and use a flotation system to separate the oil from the water or other contaminated liquid. In these and other known apparatus the recovery apparatus is both expensive and cumbersome and usually lacks efficiency. When a belt is used to accumulate the oil the squeezing of the oil from the belt often removes a small amount of water. The belt also requires frequent cleaning, and repair of the belt is time consuming and expensive. Even the detection of oil on water is an expensive proposition. This is particularly true in commercial installations where treated fluids are contaminated with unwanted oil as, for example, in the fluids used for grinding and the like.

According to the invention there is provided a contaminant recovery apparatus for removing contaminants floating on or near the surface of a contaminated fluid, the apparatus comprising: (a) a support frame; (b) a plurality of substantially like-sized discs rotatably mounted on the support frame such that, in use of the apparatus, the discs can be rotated in a position in which they are partially immersed in the fluid with the side surfaces of the discs contacting the floating contaminant, said side surfaces having an affinity for the contaminant whereby, in use, rotation of the discs causes the contaminant to be lifted from the fluid; (c) drive means to rotate the discs in a desired direction at a desired speed;; (d) at least one scraper assembly removably mounted or mountable on the support frame such that one end of the assembly rests on the support frame in a predetermined position and the assembly is held in a desired orientation, the scraper assembly comprising a flexible ribbon and a tubular conductor, the flexible ribbon being bent in such a manner that, in use of the apparatus, a portion of the length thereof is inclined upwardly with respect to a plane extending along the scraper assembly and parallel to the axis of one said disc in a sense towards said one disc and an edge of such portion is biassed into engagement with a side surface of said one disc at a position where, in use, the disc is moving downwardly back towards the fluid to scrape such side surface as the disc is rotated to remove the lifted contaminant therefrom, and the tubular conductor serving at least partially to support the flexible ribbon and being so positioned that, in use of the apparatus, a discharge exit thereof is below said portion of the flexible ribbon and the contaminant scraped from the disc by the flexible ribbon is received by the conductor and conducted to the discharge exit; and (e) means arranged to receive and accumulate contaminant leaving the discharge exit of the tubular conductor.

The invention also provides a method of recovering contaminant floating on or near the surface of a contaminated fluid using apparatus according to the invention, the method comprising fitting at least one scraper assembly so that it adopts the desired orientation, positioning the support frame so that the discs are partially immersed in the fluid with the side surfaces of the discs in contact with the floating contaminant, and actuating the drive means to cause rotation of the discs.

At least the side surfaces of the discs are preferably of a plastics which has a particular affinity for contaminants in the form of oil, oil-type products and petroleum products. Particularly effective in the pickup of oil has been polyethylene. In the embodiments of the invention to be hereinafter more fully described, the discs are preferably made of rigid polyethylene. The ribbon is preferably of plastics and as hereinafter more fully described, may be of nylon with a sufficient stiffness to provide the bias necessary to retain the ribbon in tight engagement with the side of the disc to be scraped.

In use, the discs are rotated in a partly immersed condition and as they are rotated are sequentially lifted from the contaminated fluid and are then returned to an immersed condition. The scraped residue of contaminant removed prior to reimmersion is fed to the tubular conductor and then to the receiving and accumulating means. The oil pickup efficiency of an embodiment of the invention has been found to be very good: continued rotation of the discs in oil-contaminated water and continuous scraping of the discs removed substantially all of the oil in a very short period of time.

The ribbon is preferably readily removable and replaceable in the scraper assembly. The scraper assembly is removable from the apparatus when cleaning and/or repairs are to be made. In one embodiment, to be hereinafter more fully illustrated and described, the discs and scraper assembly are protected by a cover from rain, splashing and waves so that the residue material scraped from the disc and collected is free from water as much as possible.

Whether the drive means comprises an electric motor, which is preferable, or another type of power means, it is preferably that the rotating plastics discs be turned at a slow enough speed so that the oil in the contaminated fluid, when brought into engagement with the discs is attracted by the discs and is picked up by the discs as the discs emerge from the fluid.

The invention will now be further described, by way of example, with reference to the accompanying drawings, wherein: Figure 1 represents an isometric view of a scraper assembly in which two curved plastics scraper blades (or strips) are retained in a frame and are arranged to scrape contaminant picked up from both sides of the same disc rotating in contaminated fluid; Figure 2 represents a somewhat diagrammatic side view on a reduced scale of a recovery apparatus embodying the invention and employing a respective scraper assembly as shown in Figure 1 for each of a plurality of rotating discs; Figure 3 represents an end view, partly diagrammatic, of the scraper assembly of Figure 1, with the scraper blades in effective scraping engagement with a rotating disc of the recovery apparatus, this view taken on the line 3-3 of Figure 2 and looking in the direction of the arrows;; Figure 4 represents an isometric view of a scraper assembly in which a curved plastics scraper blade is carried by a frame and is arranged so that projecting portions of this blade engage facing surfaces of two adjacent rotating discs and scrape the picked-up contaminant from these surfaces; Figure 5 represents a somewhat diagrammatic side view, on a reduced scale, of a recovery apparatus embodying the invention which employs between adjacent discs the scraper assembly of Figure 4; Figure 6 represents an end view, partly diagrammatic, of the scraper assembly of Figure 4 with the two extending edges of the scraper blade in effective scraping engagement with the facing surfaces of two adjacent rotating discs of the recovery apparatus, this view taken on the line 6-6 of Figure 5 and looking in the direction of the arrows; and Figure 7 represents a somewhat diagrammatic side view, in a reduced scale, of an oil recovery apparatus like that of Figures 2 and 5, but with a cover which prevents unwanted entry into the accumulated scrapings from the discs of water and the like which may occur because of waves, splashing, rain and the like.

Corresponding reference characters refer to like members throughout the several figures of the drawings. The drawings disclose certain details of construction for the purpose of explanation, but it should be understood that the details may be modified in various respects without departure from the scope of the invention.

Figures 1, 2 and 3 show a recovery apparatus constituting a first embodiment of the invention. The apparatus includes a scraper assembly 10 which is removably carried by a frame 12 providing a general support for the apparatus. The right or front end of the frame 12 provides a support shelf 14 having a plurality of spaced apertures for receiving and retaining pins 16. Carried on the frame 12 is a plurality of plastics discs 18 which are carried on a common shaft 20 driven by a motor 22 through a power transmission member 24 which may be a chain or belt. Depending upon whether the member 24 is a roller chain or a V-belt, appropriate sprockets or sheaves are used with the motor 22 and the shaft 20 to couple the shaft to the motor.

As seen in Figure 2, the scraper assembly 10 is supported at an angle so that gravity discharge may be used to deliver accumulated scrapings from the disc 18 into a common collector 26, The collector 26 feeds the residue to an accumulator or other disposing means (not shown). It is to be noted that the scraper assembly 10, in this particular embodiment, utilises two rectangular tubes 30 and 32. Poortions of the top and inner side of each of the tubes 30 and 32 are cut and removed to leave an outer support rib and a bottom support surface.

Two plastics scraper strips or ribbons 34 and 36 are carried by the tubes 30 and 32. The plastics strip 34 is carried in the rectangular tube 30 and the plastics strip 36 is carried in the rectangular tube 32. The right hand end of the plastics strip 34 (as seen in Figure 1) is vertically by the tube 30 and is twisted a quarter turn with the left hand held in a flat or horizontal condition by a hold down or retaining strip 38. The strip 38 is retained by flat head screws or bolts 40 which pass through apertures in the plastics strip 34 and in the bottom portion of the tube 30. The screws or bolts 40 are retained by hexagonal nuts 42. In a like manner, the plastics strip 36 has its right hand end carried in the rectangular tube 32 where it is retained in a vertical condition against the inner wall of the tube.The plastics strip 36 is twisted and the left hand or forward end is brought to a flat condition overlaying the plastics strip 34. The strip 36 is held in position by another hold-down or retaining strip 38 and screws 40 and hexagonal nuts 42. The screws 40 pass through apertures in the plastics strip 36 and in the flat bottom portion of the tube 32 to be retained by the hexagonal nuts 42. The tubes 30 and 32 are held in spaced relationship at the near or left hand end by a retaining bar 44. The tubes 30 and 32 are attached to the bar 44 as by welding, brazing or soldering. The right hand end portions of the tubes 30 and 32 are held in spaced relationship by means of a support bar 46 which may be secured to the tubes 30 and 32, as by welding, brazing or silver soldering. The retaining pin 16 is secured in the flat retaining bar 44 by threads of welding or the like.No matter how the pin 16 is secured, it is permanently affixed so that is is not lost or misplaced.

In use of the apparatus of Figures 1 to 3, as seen in Figure 2, the discs 18 are mounted on the shaft 20 and are rotated by the motor 22 in the direction indicated by the arrow. A scraper assembly- 10 is placed above a disc 18 with discharge exits of the tubes 30, 32, constituted by the ends of the tubes to the left, being positioned, as shown, to drain into the collector 26. The plastics strips 34 and 36 are placed over the disc 18 and are pushed downwardly over the disc to assume the position seen in Figure 3. The natural bias or stiffness of the strips 34, 36, cause the edges of the strips to be pressed inward- ly against the sides of the disc 18 to scrape the sides of the disc. The length of each effective scraping blade is approximately five or six inches.The pin 16 of the scraper assembly 10 is mounted in the aperture formed in the shelf 14 and its mounted condition positions and retains the scraper assembly in the desired orientation and at a desired angle or slope. As depicted in Figure 2, this arrangement provides a gravity flow of oil or other contaminant scraping carried in the tubular conductors provided by the tubes 30 and 32.

It is contemplated that instead of the pin 16 being fixed to and carried by the retaining bar 44, an aperture or apertures may be formed in the bar 44 and an appropriate number of pins 16 may be permanently secured to the shelf 14. The aperture or apertures, when formed in the bar 44, permits or permit the scraper assembly 10 to be positioned in the desired attitude and position with respect to a rotating disc 18.

Whether the pin 16 is carried by the scraper assembly 10 or is secured to the shelf 14 is merely a matter of selection since the pin establishes the position of the scraper assembly in relation to the rotating disc 18.

To replace the strips 34 and 36 it is only necessary that the scraper assembly be lifted from the frame 12. The screws 40 are loosened from the nuts 12 and the retaining strips 38 are lifted and removed from the tubes 30 and 32. The strips 34 arid 36 are removed by sliding them from- the tubes 30 and 32, and if they are excessively worn they are discarded. New plastics strips 34 and 36 with appropriate holes punched therein are then positioned in the tubes 30 and 32 and, by means of the hold-down strips 38, screws 40 and nuts 42 are secured into positions to tightly retain the plastics strips in the desired twisted attitude in the tubes 30 and 32.

The scraper assembly- 10 is brought front the top downwardly over the rotating disc 18 and the scraper edges of the plastics strips 34 and 36 are inherently moved upwardly by the method of assembly. By virtue of the stiffness of the plastics strips 34, 36 and- the created bias in the plastics strips,. there- isachieved. a tight scraping engagement of the plastics strips against the sides-of the disc 18.

The disc 18 may be made of rigid polyethylene (preferably high density) which has a great affinity or attraction for oil which then clings to the side surfaces of the disc. The scraper strips 34 and 36 may be made of nylon and are approximately one thirty-second of an inch in thickness. The strips 34 and 36 are arranged so that about five or six inches of the protruding edge of each is in engagement with the disc 18 to scrape lifted oil from the sides of the rotating disc.

Figures 4, 5 and 6 show a recovery apparatus constituting a second embodiment of the invention. It is to be noted that in Figure 4, instead of the two plastics scraper strips or ribbons, as in Figure 1, there is one plastics scraper strip 50 of which opposite side parts form respective ribbons, the strip 50 being carried in a rectangular tubular conductor or tube 52. The forward or left hand portion of the conductor 52 (as seen in Figure 4) is formed with a cut out portion 54 in both side walls which provides a shelf and openings for outward extensions of the plastics strip 50. The closed rear portion of the conductor 52 causes the plastics strip 50 to curve upwardly and inwardly to direct the scraped residue from the sides of the disc to flow into and down the conductor 52.The forward end of the conductor 52 is covered or closed by means of an angle bracket 56, a respective one of which covers the end of each of a plurality of adjacent rectangular conductors 52. Each angle bracket 56 is held in place by means of a screw 58 which passes through an aperture 60 formed in the end of the associated tubular conductor 52. Each screw 58 passes through the associated aperture 60 into a threaded aperture 62 in the angle bracket 56.

In the embodiment of Figures 4 to 6 it is to be noted that the tubular conductors 52 are as arranged in pairs. When this is to be accomplished, a rear tie-bar 70 is attached to the upper rear surfaces of the conductors 52. The underside of the front portions of the conductors 52 are secured to a support bar 72. Secured in and to this bar 72 is a positional pin 74 which fits into apertures formed in a shelf 14 at the front or right hand end, as viewed in Figure 5, of a frame 12. This is depicted in Figure 5, in which the mounting is like that of Figure 2. The frame 12 carries the shelf 14 which has the apertures therein for the placing of the pins 74 which position the ends of the conductors 52 having the cut out portions 54. If the conductors 52 are not mounted as pairs, but are arranged as single units, a pin 74 is secured to each conductor 52.In position, the strip 50 scrapes opposite faces of adjacent discs 18 which are carried by a shaft 20 in the same manner as in Figure 2. The motor 22 and power transmission member 24 are also similar to those described above with reference to Figures 1 to 3.

Referring to Figure 6, it is to be noted that in use the assembly of Figure 4 is positioned with the scraper strips 50 in engagement with the sides of discs 18. The scraper assemblies are brought into a rest position upon the shelf 14 with the pins 74 fitting appropriately positioned apertures in this shelf. In this condition, the scraper assemblies are carried by the frame 12 so that the supported tubular conductors 52 rest at an angle sufficient for scraped oil residue to be gravity fed to and along the conductors 52 to the collector 26.

Referring next to Figure 7, this shows another recovery apparatus embodying the invention which provides for those instances when it is desirable that residue (e.g. oil residue) removed from a contaminated fluid be kept as free from water as possible.

Without protection, rain and the like may enter the scraping arrangement(s) adjacent the rotating discs 18 unless prevented by cover means. In the apparatus of Figure 7, there is shown a cover 80 which is retained by and on the frame 12 and is disposed to extend substantially to or near the top level of the fluid from which a contaminant such as oil or petroleum product is to be removed. The collector 26 is shown as extending below the cover 80. However, the method of accumulation and removal of the fluid in the collector 26 is merely a matter of choice and as long as unwanted water from rain, splashing or waves is kept from the collector then the matter of water residue is limited to that picked up from the water by the rotating disc and unwanted fluid is kept to the absolute minimum.

It is to be noted that the scraper assembly 10 of Figure 1 cleans or scrapes only one disc 18. A respective scraper assembly 10 is required for each disc 18. However, the scraping of all the discs in a recovery apparatus cannot be achieved with scraper assemblies as shown in Figure 4. Additional and special scraper assemblies, not shown, are required. These special scraper assemblies are required to accommodate the outwardly facing surfaces of the two end discs.

When these end discs are to be cleaned a modification of the assembly of Figure 4 is required. Only one projecting scraper strip or blade portion is needed. This projecting blade projects only inwardly. The conductors for the special scraper assemblies need have a cutout only in one side panel from which the scraper strip extends. A right and left-hand assembly is required. No matter which and how the scraper assemblies are arranged, the thin strips will be bent to scrape the side surfaces of the discs, which strips are preferably of plastics or are plastics coated. The provided scraper assemblies may be readily removed from the support frame and the scraper blades may be readily removed from the scraper assemblies for replacement, repair and/or cleaning.As noted above, whether a pin 74 or 16 is carried by the scraper assemblies to mount into apertures in the support shelf 14 or whether a reverse or other arrangement is desired, it is only necessary that the scraper assemblies be positively positioned and prevented from moving forwardly or rearwardly in relation to the axis of the rotating discs.

Terms such as 'left', 'right', 'up', 'down', 'bottom', 'top', 'front', 'back', 'in', 'out', and the like as used herein are applicable to the arrangements shown and described in conjunction with the drawings. These terms are used merely for the purposes of description and do not necessarily apply to the position in which the oil recovery apparatus and the removable scraper assemblies may be constructed or used.

Although the above disclosure is particularly directed towards the recovery of oil and like petroleum products, the above embodiments having in fact been designed with a view to recovering such substances from water, it has been found that other contaminants may be removed by the apparatus described. As long as the contaminating material floats at or near the top of the contaminated liquid and has an affinity to the plastics coating or material that the discs are made of, the apparatus and method of recovery are highly efficient. Among the contaminants other than oil and petroleum product are some plastic resins, food particles and/or small scraps, greases in a semiliquid state and fatty acids.

WHAT WE CLAIM IS: 1. A contaminant recovery apparatus for removing contaminants floating on or near the surface of a contaminated fluid, the apparatus comprising: (a) a support frame; (b) a plurality of substantially like-sized discs rotatably mounted on the support frame such that, in use of the apparatus, the discs can be rotated in a position in which they are partially immersed in the fluid with the side surfaces of the discs contacting the floating contaminant, said side surfaces having an affinity for the contaminant whereby, in use, rotation of the discs causes the contaminant to be lifted from the fluid; (c) drive means to rotate the discs in a desired direction at a desired speed;; (d) at least one scraper assembly removably mounted or mountable on the support frame such that one end of the assembly rests on the support frame in a predetermined position and the assembly is held in a desired orientation, the scraper assembly comprising a flexible ribbon and a tubular conductor, the flexible ribbon being bent in such a manner, that, in use of the apparatus, a portion of the length thereof is inclined upwardly with respect to a plane extending along the scraper assembly and parallel to the axis of one said disc in a sense towards said one disc and an edge of such portion is biassed into engagement with a side surface of said one disc at a position where, in use, the disc is moving downwardly back towards the fluid to scrape such side surface as the disc is rotated to remove the lifted contaminant therefrom, and the tubular conductor serving at least partially - to support the flexible ribbon and being so positioned that, in use of the apparatus, a discharge exit thereof is below said portion of the flexible ribbon and the contaminant scraped from the disc by the flexible ribbon is received by the conductor and conducted to the discharge exit; and (e) means arranged to receive and accumulate contaminant leaving the discharge exit of the tubular conductor.

2. Apparatus according to claim 1, in which at least the side surfaces of the discs are of plastics material 3. Apparatus according to claim 2, in which the plastics material is polyethylene.

4. Apparatus according to claim 1, claim 2, or claim 3, wherein the flexible ribbon is of nylon.

5. Apparatus according to any one of claims 1 to 4, in which the desired orientation of the scraper assembly is provided by means of a pin carried by the scraper assembly for engagement in an associated aperture in the support frame.

6. Apparatus according to any one of claims 1 to 5, in which the scraper assembly includes two said flexible ribbons arranged so that said portions thereof are inclined upwardly towards each other to engage and scrape opposite sides of the same disc, each flexible ribbon having associated therewith a respective said tubular conductor, and each ribbon curving outwardly away from the disc to the associated conductor.

7. Apparatus according to any one of claims 1 to 5, in which the scraper assembly includes two said flexible ribbons arranged so that the said portions thereof are directed upwardly away from one another, the ribbons being carried in a common said tubular conductor such that said portions extend outwardly from the conductor so that the edges of the portions engage facing sides of adjacent discs, each ribbon curving away from the disc engaged thereby towards the conductor.

8. Apparatus according to claim 7, in which the flexible ribbons comprise opposite side parts of a single flexible strip, the strip being formed and retained in a general U-shape in the tubular conductor.

9. Apparatus according to any one of the preceding claims, in which the discs are carried on a common shaft in spaced array and the drive means comprises a motor and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. cleaning. As noted above, whether a pin 74 or 16 is carried by the scraper assemblies to mount into apertures in the support shelf 14 or whether a reverse or other arrangement is desired, it is only necessary that the scraper assemblies be positively positioned and prevented from moving forwardly or rearwardly in relation to the axis of the rotating discs. Terms such as 'left', 'right', 'up', 'down', 'bottom', 'top', 'front', 'back', 'in', 'out', and the like as used herein are applicable to the arrangements shown and described in conjunction with the drawings. These terms are used merely for the purposes of description and do not necessarily apply to the position in which the oil recovery apparatus and the removable scraper assemblies may be constructed or used. Although the above disclosure is particularly directed towards the recovery of oil and like petroleum products, the above embodiments having in fact been designed with a view to recovering such substances from water, it has been found that other contaminants may be removed by the apparatus described. As long as the contaminating material floats at or near the top of the contaminated liquid and has an affinity to the plastics coating or material that the discs are made of, the apparatus and method of recovery are highly efficient. Among the contaminants other than oil and petroleum product are some plastic resins, food particles and/or small scraps, greases in a semiliquid state and fatty acids. WHAT WE CLAIM IS:

1. A contaminant recovery apparatus for removing contaminants floating on or near the surface of a contaminated fluid, the apparatus comprising: (a) a support frame; (b) a plurality of substantially like-sized discs rotatably mounted on the support frame such that, in use of the apparatus, the discs can be rotated in a position in which they are partially immersed in the fluid with the side surfaces of the discs contacting the floating contaminant, said side surfaces having an affinity for the contaminant whereby, in use, rotation of the discs causes the contaminant to be lifted from the fluid; (c) drive means to rotate the discs in a desired direction at a desired speed;; (d) at least one scraper assembly removably mounted or mountable on the support frame such that one end of the assembly rests on the support frame in a predetermined position and the assembly is held in a desired orientation, the scraper assembly comprising a flexible ribbon and a tubular conductor, the flexible ribbon being bent in such a manner, that, in use of the apparatus, a portion of the length thereof is inclined upwardly with respect to a plane extending along the scraper assembly and parallel to the axis of one said disc in a sense towards said one disc and an edge of such portion is biassed into engagement with a side surface of said one disc at a position where, in use, the disc is moving downwardly back towards the fluid to scrape such side surface as the disc is rotated to remove the lifted contaminant therefrom, and the tubular conductor serving at least partially - to support the flexible ribbon and being so positioned that, in use of the apparatus, a discharge exit thereof is below said portion of the flexible ribbon and the contaminant scraped from the disc by the flexible ribbon is received by the conductor and conducted to the discharge exit; and (e) means arranged to receive and accumulate contaminant leaving the discharge exit of the tubular conductor.

2. Apparatus according to claim 1, in which at least the side surfaces of the discs are of plastics material

3. Apparatus according to claim 2, in which the plastics material is polyethylene.

4. Apparatus according to claim 1, claim 2, or claim 3, wherein the flexible ribbon is of nylon.

5. Apparatus according to any one of claims 1 to 4, in which the desired orientation of the scraper assembly is provided by means of a pin carried by the scraper assembly for engagement in an associated aperture in the support frame.

6. Apparatus according to any one of claims 1 to 5, in which the scraper assembly includes two said flexible ribbons arranged so that said portions thereof are inclined upwardly towards each other to engage and scrape opposite sides of the same disc, each flexible ribbon having associated therewith a respective said tubular conductor, and each ribbon curving outwardly away from the disc to the associated conductor.

7. Apparatus according to any one of claims 1 to 5, in which the scraper assembly includes two said flexible ribbons arranged so that the said portions thereof are directed upwardly away from one another, the ribbons being carried in a common said tubular conductor such that said portions extend outwardly from the conductor so that the edges of the portions engage facing sides of adjacent discs, each ribbon curving away from the disc engaged thereby towards the conductor.

8. Apparatus according to claim 7, in which the flexible ribbons comprise opposite side parts of a single flexible strip, the strip being formed and retained in a general U-shape in the tubular conductor.

9. Apparatus according to any one of the preceding claims, in which the discs are carried on a common shaft in spaced array and the drive means comprises a motor and

a power transmitting means connecting the motor to the shaft.

10. Apparatus according to any one of the preceding claims, in which the ribbon is approximately one thirty-second of an inch in thickness.

11. Apparatus according to any one of the preceding claims, including a cover by which the discs and the tubular conductor or conductors are shielded from spray, waves and other sources of fluid which would add unwanted fluid to the contaminant scraped from the rotating discs.

12. A contaminant recovery apparatus for removing contaminants floating on or near the surface of a contaminated fluid, the apparatus being substantially as herein described with reference to Figures 1 to 3, Figure 4 to 6, Figures 1 to 3 and 7 or Figures 4 to 7 of the accompanying drawings.

13. A method of recovering contaminant floating on or near the surface of a contaminated fluid using apparatus according to any one of the preceding claims, the method comprising fitting at least one scraper assembly so that it adopts the desired orientation, positioning the support frame so that the discs are partially immersed in the fluid with the side surfaces of the discs in contact with the floating contaminant, and actuating the drive means to cause rotation of the discs.