NZ313929A - A skimmer - Google Patents

Description

New Zealand No 313929 International No PCT/AU96/00504 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates 11 08 1995, Complete Specification Filed 12 08 1996 Classification (6) E03F5/14 Publication date 28 October 1999 Journal No 1445 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention A skimmer Name, address and nationality of applicant(s) as in international application form INTERNATIONAL FLUID SEPARATION PTY. LTD , 27 Tourello Avenue, East Hawthorn, Victoria 3123, Australia A SKIMMER 'The present invention relates generally to a method and apparatus for separating two different materials, particularly a fluid and a solid material, anfl more 5 particularly to a method and apparatus for separating solid material of relatively large size from a liguid. Even more particularly, the present invention relates to a pretxeatment or preliminary step, such as a method and apparatus for separating debris, rubbish, leaves or the 10 like from contaminated water which is to be treated. In particular, the present invention relates to a skimmer, particularly a skimmer used m an installation for separating oil from water, particularly water contaminated by petroleum products, including oils and the like. Even 15 more particularly, the present invention relates to the use of a skimmer m the first step of an overall process of cleaning water, such as run-off water m an environment m which hydrocarbon oils such as motor-engine oils are used, sufficiently to enable the water to be discharged to the 20 normal sewerage or drainage systems Although the present invention will be described with particular reference to a skimmer used to separate relatively large-sized trash, rubbish, debris or the like from contaminated water as the first step m an overall oil 25 and water separation installation, it is to be noted that the skimmer of the present invention is not restricted m scope to the described embodiment or to the described use but rather the scope of the present invention is sufficiently broad to encompass other arrangements of the 30 skimmer, and other uses, and application of the various forms of the skimmers.

In commercial or large scale cleaning and/or separating Printed from Mimosa 11 20 50 lnstallationB, particularly installations having one section open to the elements, rubbish and other debris sncii as packaging, paper cups, leaves, grass and the like settles onto the surface of a vat, tank, pit, pond or 5 similar body of water which has been collected prior to being treated Even in installations not open to the -elements, rubbish can accumulate on the surface of the water in the collection area In installations where the water is contaminated with a liquid having a lower density 10 than that of water, such as for example an oil, particularly a petroleum-derived product such as engine oil, it is necessary to take the water from the top surface of the water layer at about the interface of the oil and water to ensure that the water is contaminated with 15 sufficient oil for economic operation of the installation to ensure separation of the oil and water and to ensure that excessive amounts of oil are not admitted undiluted to the separation installation at concentrations of oil in excess of the operating parameters of the installation 20 otherwise such installations will not properly separate the oil and water The concentration of the oil m the water should be within a well defined range Skimmers are used m such applications to admit the required amount of oil and water However, skimmers hithertobefore available have 25 suffered one or more serious disadvantages One disadvantage is caused by the debris that falls into the pit, pond, tank or similar in that large size debris, such as packaging, twigs, leaves, grass and the like clogs the inlet to the skimmer, preventing the ingress of sufficient 30 quantities of contaminated water for efficient, effective operation of the cleaning and/or separating installation One attempt to overcome this is to place small size open mesh or equivalent over the inlet to filter the debris from the water before the water is admitted to the skimmer 35 However, due to the small size of the spacing in the mesh, the mesh quickly becomes clogged or blocked, particularly with vegetation such as leaves and the like, preventing the Printed from Mimosa 11 20 50 WO 97/07298 PCT/AU96/00502 further ingress of water.

Other arrangements of providing a filtering means to prevent the ingress of trash, rubbish, vegetation, leaves and the like have not been entirely satisfactory for much 5 the same reason that the filtering means becomes clogged, requiring periodic maintenance and cleaning. In some cases, the filtering installation must be deemed twice or more daily m order for it to be effective. Therefore, there is a need to provide an effective screening of 10 rubbish, debris and the like from entering the skimmer, or more particularly from entering the separating/cleaning installation, which does not require excessive cleaning and maintenance.

Accordingly, it is an aim of the present invention to 15 provide a skimmer arrangement having an effective and efficient filtering means which prevents the inlet from becoming blocked, clogged or the like due to trash, leaves, debris or similar, or when the filter does become blocked it may be easily cleaned, thus requiring much less 20 maintenance.

According to the present invention there is provided an apparatus for separating a first material from a second material, such as for example a skimmer or barrier, said apparatus comprising an inlet means provided with at least 25 one inlet port at least partially defined by a wall portion wherein at least a portion of the wall defining the inlet port is curved, said curved wall portion facilitating admission of a first material to the apparatus while substantially preventing or substantially orienting ingress 3 0 of a second material to the apparatus, wherein said second material after contacting the curved wall portion is either prevented from entering the inlet port when the material is above a predetermined size or is directed or otherwise guided into a preselected orientation for acimission to the INTELLECTUAL PROPEB^OFFICE OF NZ 1 - SEP 1999 Dcrci\/cn inlet port an the preselected orientation when below a predetermined size or of a preselected shape for collection at a remote location within the skimmer.

Typically, the first material is a fluid, more typically a 5 liquid, most typically water contaminated with a hydrophobic or oleophilic material, such, as for example an oil, particularly a petroleum-based product, especially a motor-engine oil or similar.

Typically, the second material is debris, rubbish, trash, leaves, grass, vegetation or similar large particle size solids material More typically, the second material floats on the surface of the first material. Even more typically, the second material has a major axis which extends lengthwise along the material.

Typically, the material is acicular or other similar elongate shape. More typically, the material is oriented to flow m the same direction as its longitudinal or lengthwise extending axis after contacting the curved wall portion of the inlet means 2 0 Typically, there are one, two, three, four or more inlet ports comprising the inlet means More typically, each inlet port is provided with a curved wall portion defining at least a part of the port Even more typicrlly, there are up to eight or more inlet ports, each port having or being associated with its own curved wall portion. Even more typically, the inlet ports are spaced apart from each other, typically regularly spaced apart from each other around the circumference of a circle or other similar closed loop arrangement Typically, the inlet comprises an inflow weir, preferably having cut-outs or other flow control means. Typically, the base of the skimmer is fixed so as to be submerged and Printed from Mimosa 11 20 50 the top floats at or about water level.

Typically, the skimmer of the present invention is provided with a flexible membrane. More typically, the flexible membrane is cylindrical m shape and impervious to the 5 fluid m which the skimmer is partially submerged. Even more typically, the membrane is a sock or stocking material impregnated with a silicon.

Typically, the membrane is located intermediate the fixed stationary baBe of the skimmer and the floating top portion 10 of the skimmer to accommodate fluctuations m the height of the top portion m accordance with variations of the water level Typically, the skimmer of the present invention is provided with a plurality of buoyancy tanks located at regular 15 spaced apart intervals circumferentially around the periphery of the skimmer. Each buoyancy tank is substantially circular in shape having at least a curved wall portion More typically, the inlet port is defined between the curved wall portions of adjacent buoyancy 20 tanks Typically, the means for directing or otherwise guiding debris and rubbish into a preselected orientation, is the curved walls of adjacent buoyancy tanks.

Typically, the skimmer of the present invention is provided 25 with a removable receptacle for containing debris, rubbish and the like whilst allowing flow through of contaminated water.

Typically, the skimmer of the present invention is adapted to float at or near the water level by altering the 30 buoyancy effect of the buoyancy chambers Printed from Mimosa 11 20 50 The present indention wall now be described by way of example with reference to the accojqpanymg drawings in which: Figure 1 is a vertical cross-section of one form 5 of the skimmer of the present invention; Figure 2 is a plan view of the inlet of the skimmer of Figure 1; Figure 3 is a vertical cross-section of a further form of the skimmer of the present invention, 10 Figure 4 is a vertical cross-section of a still further form of the skimmer of the present invention, Figure 5 is a plan view of the skimmer of Figure 4.

Xn Figures 1 and 2, there is shown a first form of a 15 skimmer in accordance with the present invention, generally denoted as 2. Skimmer 2 has a generally circular or annular inlet means 4 located at or towards the topmost surface of the top of the skimmer. Inlet 4 is defined by a cylindrical housing 6 made from a suitable material, such 20 as for example plastics material, which is opened at the top to form the inlet 4 and open at the bottom 5 to form a throat or similar. Axi annular insert 8 is located within the top of housing 6 and is provided with an inflow weir portion 10 located around the upper end of housing 6. Weir 25 10 is optionally provided with a number of cut-outs (not shown) or other means to allow water to be admitted to skimmer 2 through inlet 4. Insert 8 is made from any suitable material, such as for example polyurethane foam or the like. Weir 10 is made with suitable dimensions, weight 30 and buoyancy, along with housing 6, to float so that the top of weir 10 is ;just above the water level of the pond in which the skimmer 2 is located so that contaminated water may be admitted in controlled amounts through the cut-outs positioned at a lower level than the top of weir 10.

Housing 6 is provided with a circumferential flange portion Printed from Mimosa 11 20 50 WO 97/0729S 14 around its lower end in use The outer surface of flange portion 14 is rebated inwards with respect to the outer surface of housing 6. A flexible sock, stocking, mash 16 or other flexible impervious membrane is securely 5 attached to the outer Burface of flange 14 by a suitable fastening means, such as for example a circumferential strap 18, ring or similar. Therefore, sock 16 is securely attached around the lower in use edge of housing 6. Sock 16 is made from any suitable flexible material which is 10 impervious to water One particularly suitable material from which sock 16 is made is a heavy duty stocking material impregnated with a waterproof silicon material.

Skimmer 2 further comprises skimmer body 22 having a circumferential flange 24 or collar extending outwardly 15 therefrom in an m use upwards direction towards housing 6 and membrane 16. The lower end of sock 16 is received over flange 24 and securely attached thereto by strap 26, ring clamp or similar located around the outer surface of sock 16 and flange 24 Body 22 as provided with an inlet throat 2 0 54 or similar for admitting water from the inlet 4 after passing through the cavity formed by the membrane into body 22 and is provaded with outlet 3 0 to discharge the contaminated water free of debris or the like to the next step in the overall cleaning process to separate the oil 25 from the water. Outlet 30 is connected to suitable discharge conduits (not shown) for conveying contaminated water free of debris to a suitable cleaning installation for separating the oil from the water.

With particular reference to Figure 2, insert 8 is, m one 3 0 embodiment, formed with three generally arcuate shaped inlet ports 32 separated by a generally Y-shaped web portion having three curved legs 33 generally arranged at 120° to each other about a central portion 34 It is to be noted that inlet 10 is arranged so that each inlet port 32 35 is defined by a curved wall portion 38 of housing 6 around Printed from Mimosa 11 20 50 one side and a curved wall portion 36 formed from two adjacent legs 33.

In operation of this form of the present Invention, skimmer 2 is located at the bottom of a pit or other suitable 5 container of water Buch as a tank, pond, weir or the like, such that the base of body 22 rests upon the bottom of the pit, pond or similar and the top edge of inlet 10 is located about the level of the water, denoted by reference numeral 39 in Figure 1, with the top of weir 10 rjust above 10 water level 40 It is to be noted that m this embodiment that the base of body 22 is located on che floor or base of the pond or vat and that the housing 6 is free to float on or close to the surface of water 3 9 m accordance with variations m the water level 3 9 by means of flexible sock 15 16 interconnecting body 22 and housing 6 either expanding or contracting as the contaminated water is selectively collected and discharged Thus, inlet 4 is always able to receive contaminated water from the pond or similar.

Any leaves, debris or other large size particles are 20 prevented from entering inlet 4 by being too large to pass through one of ports 32. Any debris of a size which is smaller than the inlet port 32 is oriented or directed into the desired orientation by contact with the curved wall 36 of either weir 10 or curved wall 3 8 of housing 6. This 25 form of the present invention finds particular application for use in connection with a small scale or small capacity tank or container m which there is little variation in the level of the water by being located at the bottom of the tank. Such a skimmer is generally known as a fixed skimmer 30 since it is fixed or otherwise fastened to the base, bed, floor, of the tank or pond m which it is located even though inlet 4 is free to float on or about the water surface or level 39 When cleaning of skimmer 2 is required, skimmer 2 can be Printed from Mimosa 11 20 50 retrieved or otherwise exposed and strap 26 unfastened allowing housing 6 to be separated from body 22, such as by strap 18 being loosened thereby allowing easy cleaning of the device and its components One embodiment of this form of the skimmer (not shown) is provided with a two-part body in place of the one-piece body 22, the two-part body comprising a main body portion which has the discharge outlet 30 and a base cap threadingly connected to the base of mam body portion. In 10 Addition, a cylindrical strainer is provided below inlet throat or aperture 54 inside the mam body When it is desired to clean this form of the skimmer, the base cap can be easily removed by threadingly disengaging it from the base of body 22 so that the strainer can be removed or 15 cleaned while the skimmer remains m situ This embodiment obviates the need to remove the sock 16 from the main body 22 by unfastening the strap 26 and thus maintenance can be performed more easily and efficiently.

With particular reference to Figure 3, a further embodiment 20 of the present invention will now be described. In Figure 3 there is shown a further form of the skimmer of the present invention generally denoted as 40 Skimmer 40 has many parts in common with skimmer 2, and accordingly the same reference numerals will be used to describe similar 25 parts in both Figures 1 and 3 with respect to skimmer 2 and 40 respectively.

Skimmer 40 is provided with circular or annular housing 6 having a lower m-use flange portion 14 as previously described An insert B is located within the upper end m 30 use of housing 6 and is provided with an upstanding inflow weir portion 10 forming an inlet 4 to skimmer 40 Weir 10 is provided with a number of cut-outs (not shown) or similar depressions m its surface thus allowing water to flow over or through the depressions for admission Printed from Mimosa 11 20 50 internally into skimmer 40. Alternatively, or additionally, insert B, and optionally housing 6, may be provided with ports to admit water into skimmer 40 through the ports located in the side wall of the upper portion of 5 skimmer 40.

A flexible impervious membrane in the form of a sock 16 is securely fastened to the outer surface of flange 14 by Btxap IB or similar ring clamp "Thus, m one embodiment of this form of the invention the upper portion of skimmer 4 0 10 is the sause as or similar to the upper portion of skimmer 2 Skimmer 4 0 is provided with a modified body portion 42 which is a modified form of body portion 22 Body portion 42 is essentially bowl-shaped having a cylindrical side 15 wall 44 m which is located an outlet 46 for discharging contaminated water via a suitable discharge conduit not shown and at a lower portion of wall 44 there is provided a dram 48, located remote from outlet 46, such as on the diagonally opposite side of body 42 to where outlet 46 is 20 located. The upper circular edge of wall 44 defines a circular opening m which m use is received a lid 50 which is sealingly engageable with a flange 52 located circumferentially around the open upper end m use of body 42. Lid 50 is sealingly connected to body 42 Lid 50 is 25 provided with, an upstanding flange or collar 24 forming a circular opening inside the annular wall of collar 24 to which the lower end m use of sock 16 is securely faatened by means of a circumferential strap 26 or ring clamp or similar as described previously.

Collar or flange 24 may be integrally formed with, lid 50 or may be securely fastened to lid 50 in the area around or forming the circumference of aperture 54 Lid 50, m one form, is made from a flexible or resilient material, such as rubber or plastics material The peripheral edge of lid Printed from Mimosa 11 20 50 PCT/AU9G/00502 50 is elastically deformable so as to be snugly receivable between flange 52 and securely held m plare A circular support ring 53 forming the top edge of wall 44 is provided around the circumference of the open end of body 42 and is 5 located relatively m-board of flange 52 The lower surface in use of lid 50 is provided with a circular or annular groove 5 6 formed by downwardly depending circular projection 58. Groove 56 has an outboardly directed semi-circular or similar curved profile 10 for receiving a rubber O-rmg 60 therein to provide a seal between lid 50 and a trash basket 61 downwardly depending from the underside of lid 50. Lid 50 is provided with a centrally located aperture 54 which in use is located m alignment with the opening formed by circular collar or 15 flange 24 to allow contaminated water to flow freely into the body 42 of skimmer 4 0 in. use Trash basket 61 is made from an open mesh material or similar apertured material for retaining relatively large size material whilst allowing the through flow of 20 contaminated water is sealingly interconnected to the underside of lid 50 by means of rubber O-rmg 60 or similar Trash basket 61 may be easily removed from lid 50 for cleaning of basket 61 and replaced due to the sealing press fit of the upper circumferential edge of trash basket 25 61 contacting O-rmg 60.

An elongate handle 62 extends from the base of the trash basket 61 through aperture 54, through circular collar 24, through opening 5 and inlet 4 to extend substantially vertically outwardly above the top of skimmer 40 to enable 30 trash basket 61 and associated components such as lid 50 to be removed from body 42 while the skimmer 4 0 is retained in situ m the pond or similar. One end of handle 62 is securely fastened to the base of trash basket 61 and handle 62 is provided at the other end with an eye 64 to which a Printed from Mimosa 11 20 50 suitable rope, lanyard or the like (not shown) may be attached to assist in retrieval of the skimmer 40 from the pond and the trash basket 61 from the skimmer 40 Operation of skimmer 40 is similar to that of skimmer 2 5 except that skimmer 40 can be either fixed m place as m the case of skimmer 2 or may float in a suitable container such as a tank, pit, pond or the like in which it is located. The discharge pipe or conduit connected to outlet 46 may be either fixed or flexible, depending on whether 10 body 42 is fixed in place or whether Bkimmer 40 is free to float. If skimmer 40 is fixed m place, housing 6 floats at a level so that weir 10 is slightly above water level 3 9 and any variation m the water level 39 is accommodated by movement of housing 6 and sock 16 to maintain housing 6 in 15 fluid communication with body 42. If skimmer 40 is free to float in its entirety, it adopts a position in which weir 10 is located above water level 39 A further form of the skimmer of the present invention which is shown m Figures 4 and 5 will now be described 20 The skimmer of Figures 4 and 5, generally denoted as 80, is similar to skimmer 40 apart from Bkimmer 80 additionally having a plurality of buoyancy chambers 82, 83 located circumferentially at spaced apart locations around the circumference of body 42. Similar reference numerals to 25 those used m the description of the embodiment of Figure 3 will be used to describe the embodiment of Figures 4 and 5.

In this embodiment there are eight separate buoyancy chambers 82, 83 located at regularly spaced apart intervals circumferentially around the perimeter of the skimmer 30 surrounding housing 6 and sock 16 of the skimmer. With particular reference to Figure 4, it can be seen that one form of the buoyancy chamber, denoted as 82, is formed with the inner cylindrical wall 84 formed as a continuation of flange 52 of the embodiment shown m Figure 3 Inner wall Printed from Mimosa 11 20 50 84 extends from outlet 46 at the lower end in use to above the level of inflow weir 10 Buoyancy chamber B2 is formed with circular base 86 and top circular disc 8B provided with aperture 90 which is provided with a suitable closure 5 means (not shown) for maintaining a desired air space in buoyancy chamber 82 Upper surface 88 is provided with upstanding circular flange 92 which surrounds the upper portion of the skimmer Another form of the buoyancy chamber useful with skimmer 80 10 is denoted as 83 m Figure 4 Buoyancy chamber 83 has an inner cylindrical wall 84 formed as a continuation of flange 52 and is provided with a base 85 having a centrally circular opening 87 for allowing ingress of water into the interior of the chamber 83. A small air release hole 89 is 15 provided in the outboard side of wall 84 to determine the level to which water rises inside chamber 83. In this manner the air hole can be located at a preselected position to control the height at which the skimmer floatB m water It is to be noted that the one skimmer 80 can 20 have all the same types of chambers or a mixture of chambers With particular reference to Figure 5, there can be seen an inlet port 94 located between two adjacent buoyancy chambers 82. Inlet port 94 may extend to any desirable or 25 suitable depth between the top and base of the buoyancy chambers In one example, inlet port 94 is open over the entire height of buoyancy chamber 82 In operation of skimmer 80, the skimmer is located on the surface of a suitable tank or the like such that the water 3 0 level 39 is just below inflow weir 10. The position of skimmer 80 may be accurately determined by altering the amount of lift from the buoyancy chambers 82 Any debris or rubbish in the vicinity of skimmer 80 is Printed from Mimosa 11 20 50 PCT/AU96/005Q2 forced to flow cowards Bkimmer 80 whereupon it contacts the curved walls 84 of buoyancy chambers 82 Any rubbish larger than the spacing between adjacent buoyancy tankB 82, that is, larger than inlet port 94, is prevented from 5 entering into the interior of skimmer 80. Any material small enough to pass through port 94 is oriented m its lengthwise extending direction so as to flow between adjacent buoyancy chambers 82 with its lengthwise extending direction aligned m the direction of flow Thus, the 10 curved walls 84 act as a guiding or directing means to orient and direct rubbish of a preselected size and shape to flow in a preferred orientation into inlet 4 of skimmer 80. Rubbish in this orientation flows through inlet 4, opening 5, and through aperture 54 into trash basket 61 15 where it is collected. Due to the orientation of the rubbish, it does not span inlet 94 nor inlet 4 to cause blockage or clogging of the inlet, but rather flows directly into trash basket 61 without hindering or adversely affecting the flow of contaminated water through 20 the skimmer Thus, using the skimmer of the present invention, the rubbish collects in the trash basket which can be emptied periodically.

It is to be noted that the base of trash basket 61 is located below the level of discharge outlet 46 so that, as 25 the rubbish accumulates at the bottom of trash basket 61, contaminated water can flow through the skimmer for discharge through outlet 46. The accumulating rubbish does not block or clog discharge outlet 46 or interrupt the flow of contaminated water through the skimmer 3 0 One modification of the buoyancy tanks of this form of the skimmer is to provide different sized buoyancy tanks around the outBide of the skimmer which allows the skimmer to be selectively adjusted in position in use. The modified buoyancy tanks may be sealed or partially sealed and may be 35 filled with any suitable material assisting an flotation.

Printed from Mimosa 11 20 50 such, as for example filled with a gas or filled with buoyancy aids such as flotation Bpheres like polystyrene beads or the like Advcintages of the present invention include the following- - The skimmer of the present invention is cheap to manufacture and inexpensive to operate The guiding means for directing or orienting rubbish allows the rubbish to be oriented m a preselected orientation allowing accumulation of 10 rubbish m a trash basket without affecting the through flow of contaminated water This results in less maintenance and more efficient operation of the skimmer The described arrangement has been advanced by explanation 15 and many modifications may be made without departing from the spirit and scope of the invention which includes every novel feature and novel combination of features heremdisclosed Those skilled m the art will appreciate that the invention 20 described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope.

Printed from Mimosa 11 20 50

Claims (1)

1. - lb " WHAT WE CLrtIM IS 5 1) An apparatus for separating a first material from a second material, comprising an inlet means provided with at least one inlet port which is at least partially defined by a wall portion, wherein at least a portion of the wall defined m the inlet port is curved, said curved wall 10 portion facilitating admission of the first material to the apparatus whilst substantially preventing or substantially orienting ingress of a second material to the apparatus, wherein said second material after contacting the curved wall portion is either prevented from entering the inlet 15 port when the second material is above a predetermined size or is directed or otherwise guided into a preselected orientation for admission to the inlet port m the preselected orientation when below a predetermined size or a predetermined shape for collection at a remote location 20 within the apparatus, and wherein the apparatus comprises a top portion and a base portion wherein, in use, the base of the apparatus is submerged whereas the top portion is free to adopt a level m accordance with the level of the first material in. which the apparatus is located. 25 2) An apparatus according to claim 1 m which the first material is a fluid. 3) An apparatus according to claim 2 m which the 3 0 fluid is water contaminated with a hydrophobic or oleophilic material. 35 4) An apparatus according to claim 3 m which the hydrophobic or oleophilic material is an oil. 5) An apparatus according to claim 4 m which the oleophilic material is a petroleum product. intellectual property office of nz ! 1 - SEP 1999 -17 - 6) An apparatus according to claim 5 m which, the petroleum product is a motor-engine oil. 5 7) An apparatus according to any one of claims 3 to 6 in which the second material is debris, rubbish, trash, leaves, grass or vegetation which floats on the surface of the water. 10 8) An apparatus according to any preceding claim in which the second material has a ma^or axis which extends lengthwise along the material in that the material is substantially acicular or elongate in shape. 15 9) An apparatus according to claim 8 in which the second material is oriented to flow m the same direction as its longitudinal or lengthwise extending axis after contacting the curved wall portion or the inlet means. 2 0 10) An apparatus according to any preceding claim in which the inlet means comprises one, two, three, four or more inlet ports, wherein each inlet port is provided with one or more curved wall portions defining at least a part of the inlet port. 25 11) An apparatus according to claim 10 m which there are up to eight or more inlet ports, each port having or being associated with one or more curved wall portions. 3 0 12) An apparatus according to claim 10 or 11 m which the inlet ports are spaced part from each other. 13) An apparatus according to claim 12 m which the inlet ports are regularly spaced apart from each other 35 around the perimeter of the apparatus. 14) An apparatus according to any preceding claim in j INTELUXTUAL"P ROP EKTY 0 F FICI of nz | 1 - SEP 1999 j rn I r— r* I \ / r* nk - 18 ~ which the inlet means comprises an inflow weir having cutouts or other flow control means located at spaced apart locations around the top edge of the inflow weir. 5 15) An apparatus according to any preceding claim further comprising a flexible membrane means interconnecting the base portion and the top portion of the apparatus. 10 16) An apparatus according to claim 15 m which the flexible membrane is cylindrical in shape in use and impervious to the fluid in which the apparatus is located. 17) An apparatus according to claim 15 or 16 in which 15 the flexible membrane i'« a sock or stocking material impregnated with a silicone or silicone rubber or similar material. 18) An apparatus according to any one of claims 2 to 2 0 17 further comprising a plurality of buoyancy tanks to enable at least the top portion of the apparatus to adopt a predetermined or preselected location within the fluid in which it is located. 2 5 19) An apparatus according to claim 18 in which the buoyancy tanks are located at regularly spaced apart intervals circumferentially around the periphery of the apparatus. 3 0 20) An apparatus according to claim 18 or 19 in which the buoyancy tank is substantially circular in shape having at least a curved wall portion. 21) An apparatus according to any one of claims 18 to 35 20 m which the inlet port is defined between the curved wall portions of two adjacent buoyancy tanks. Intellectual property ofhcc j of n z I 1 - SEP 1999 RECEIVED _ 19 22) An apparatus according to any preceding claim further comprising a removable receptacle for containing debris, rubbish or vegetation whilst allowing flow through of contaminated water. 5 23) An apparatus according to any one of claims 18 to 22 m which at least the top portion of the apparatus or the apparatus itself is adapted to float at or near the water level in which it is located under the buoyancy 10 effect of the buoyancy tanks. 24) An apparatus according to any one of claims 2 to 23 in which the apparatus is adapted to be fixed at or towards the base of a vessel, pond, vat, tank or container 15 for holding the contaminated water. 25) An apparatus according to any preceding cLaim further comprising an outlet port or discharge means for discharging contaminated water substantially free of 20 debris, rubbish, trash, vegetation or leaves. 26) An apparatus according to any preceding claim which is a skimmer for separating debris from contaminated water. 25 27) A method of separating a first material from a second material using an apparatus according to any preceding claim. 30 28) An apparatus for separating a first material from a second material substantially as hereinbefore defined with reference to the accompany drawings. "ND OF CLAIMS By tho authorised dg^nts intellectual tiwtm wlce of nz 1 - SEP 1399 RECEIVED