AU2008255171A1 - Evaporation Reduction Module - Google Patents

Description

P/00/009 Regulation 3.10 5 AUSTRALIA Patents Act 1990 10 COMPLETE STANDARD PATENT SPECIFICATION 15 Invention Title: 20 EVAPORATION REDUCTION MODULE 25 The invention is described in the following statement, including the best method of performing it known to us: 30 35 40 45 Our Ref: 082051 50 - 2 EVAPORATION REDUCTION MODULE The present invention relates to water conservation and, more particularly, to apparatus and methods for the reduction of evaporative loss from exposed bodies of water. 5 BACKGROUND It is well known that, particularly in warmer climatic conditions, loss from exposed water storage facilities such as dams and lakes through evaporation can be significant. 10 Various attempts have been made to devise ways in which such evaporative loss can be prevented or at least reduced. Various arrangements of modular covers are known, which when clustered together reduce the exposure of surface water to the atmosphere. 15 A problem of devising a modular cover arrangement for extensive bodies of open water is to make the individual modules simple and cheap enough to make such coverings economically.viable, Another problem with known covers is that under high wind conditions with choppy water, some 20 covers may be blown off the water surface or be driven up over adjoining modules. It is an object of the present invention to address or at least ameliorate some of the above disadvantages. 25 -3 Notes 1. The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the 5 exclusive sense of "consisting only of". 2. The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled 10 in the art in any country. BRIEF DESCRIPTION OF INVENTION Accordingly, in a first broad form of the invention, there is provided a water evaporation reduction module for an exposed water surface; said module comprising at least one 15 air retaining floatation chamber; said module further comprising submerged surface areas suspended below an underside of said chamber; said submerged surface areas substantially parallel to said underside; said surface areas reacting against water flowing between said surface 20 areas and said underside to resist lifting of said module from a water surface when said module is in use. Preferably, said at least one floatation chamber comprises a generally planar semi-rigid base sheet and a generally dome-shaped cover sealingly attached to said base sheet; 25 space between said generally dome-shaped cover and said - 4 base sheet enclosing a volume of air sufficient to provide floatation to said module. Preferably, said base sheet has a polygonal shape. Preferably, said polygonal shape is hexagonal. 5 Preferably, said submerged surface areas comprise upper surfaces of a plurality of separate sheet segments radially arranged relative to the centre of said polygonal base sheet; inner ends and outer ends of said sheet segments connected to said underside of said chamber by respective 10 inner and outer supporting elements; said supporting elements substantially normal to an underside of said base sheet. Preferably, said sheet segments and said supporting elements form structures at said underside of said base 15 sheet; said structures separated by gaps to allow flow of water through said gaps, and between said underside and said upper surfaces of said sheet segments. Preferably, said elements at said inner end and said outer end of a said sheet segment are integral with said sheet 20 segment. Preferably, a said supporting element at said outer end of a said sheet segment is attached at an edge of said polygonal base sheet; said sheet segment attached at an - 5 inner end to a cylindrical element depending from said centre of said underside of said base sheet; said supporting element at said outer end and said cylindrical element at said inner end extending equally below said 5 underside of said chamber so as to suspend said sheet segment substantially parallel to said underside. Preferably, said submerged surface areas comprise an upper surface of a sheet of material; said sheet of material generally coextensive in area with said polygonal base 10 sheet; said sheet of material suspended below said underside of said chamber by supporting elements at each corner of said polygonal base sheet; each said supporting element extending part way along adjacent polygonal sheet edges from a said corner so as to leave openings between a 15 supporting element at a given corner and supporting elements at adjacent corners. Preferably, said sheet of material is provided with apertures; said apertures adapted to allow flow of water through said apertures and through said openings between 20 said supporting elements at said corners. Preferably, said sheet of material suspended below said underside of said module is substantially planar and parallel to said underside.

-6 Preferably, said sheet of material suspended below said underside of said module is convex; a central portion of said sheet of material being closer to said underside than peripheral portions of said sheet. 5 Preferably, said submerged surface areas comprise the upper surface of a generally disc shaped member attached to a central mast depending from an underside of said floatation chamber. Preferably, buoyancy of said module is arrange so that said 10 module floats on a said water surface with said cover substantially exposed above said water surface; edges of said cover submerged below said water surface. Preferably, said generally dome shaped cover is adapted to minimise wind resistance to laminar wind forces at said 15 water surface. Preferably, lifting forces tending to lift said module are forces generated by wind and wave action at said water surface. Preferably, said module includes six floatation chambers. 20 Preferably, at least one of said at least one floatation chamber is filled with foam.

-7 In a further broad form of the invention, there is provided a method of reducing water evaporation from a body of water; said method including the steps of: (a) providing a plurality of floating modules; each of 5 said modules comprising at least one floatation chamber and submerged surface areas, (b) shaping said modules so as to minimise uncovered water surface when said modules are clustered together, 10 (c) suspending said submerged surface areas below said floatation chamber to allow flows of water between an underside of said chamber and said surface areas, said water and said submerged surface areas interacting to provide resistance to lifting forces 15 acting on said modules. In yet another broad form of the invention, there is provided a method of providing resistance to dislodgement of an evaporation reduction module from the surface of a body of water by wind and wave action; said method 20 including the steps of: (a) providing said evaporation reduction module with a generally dome-shaped cover, - 8 (b) suspending submerged surface areas below said module, wherein said submerged surface areas are generally parallel to an underside of said module with water 5 flowing between said underside and said submerged surfaces. BRIEF DESCRIPTION OF DRAWINGS Embodiments of the present invention will. now be 10 described with reference to the accompanying drawings wherein: Figure 1 is a sectioned elevation view of an evaporation reduction module according to a first preferred embodiment of the invention, 15 Figure 2 is an orthogonal view from below of the module of Figure 1, Figure 3 is a perspective view from below of the module of Figures 1 and 2, Figure 4 shows a typical clustering of a number of the 20 modules of Figures 1 to 3 in use on a water surface, Figure 5 is a sectioned elevation view of a second preferred embodiment of an evaporation reduction module according to the invention, Figure 6 is an orthogonal view from below of the 25 module of Figure 5, Figure 7 is a perspective view from below of the module of Figures 5 and 6 Figure 8 is a sectioned elevation view of a third preferred embodiment of an evaporation reduction module 5 according to the invention, Figure 9 is an orthogonal view from below of the module of Figure 8, Figure 10 is a further sectioned elevation view of an alternative arrangement of the third preferred embodiment 10 of the invention, Figure 11 is a perspective view from below of the module of Figures 8, 9 and 10, Figure 12 is a perspective view from above of a fourth preferred embodiment of an evaporation reduction module 15 according to the invention, Figure 13 is a partly cut away view from below of the module of Figure 12, Figure 14 is a side elevation view of the module of Figures 12 and 13, 20 Figure 15 is a partly cut away plan view of the module of Figures 12 to 14, Figure 16 is a partly cut away side elevation view of the modules of Figures 12 to 15, Figure 17a to 17d are orthogonal underside, side and 25 top views and a perspective view of another preferred embodiment of the invention.

- 10 DETAILED DESCRIPTION OF PREFP4ED EMBODIMENTS First Preferred Embodiment 5 With reference to Figures 1 to 3, in a first preferred embodiment of an evaporation reducing module 10, the module comprises a floatation chamber 12 and submerged surface areas 14 suspended below the underside of the chamber 12. Floatation chamber 12 is formed of a substantially 10 planar polygonal semi-rigid base sheet 16 of impervious, preferably polymer material, and a cover 18. Preferably, base sheet 16 is hexagonal in shape so that when modules 10 cluster together they interlock to form a virtually continuous cover over a water surface, as shown in Figure 15 4. Cover 18, also of an impervious material, is in the form of a low profile dome and is attached to the edges 20 of base sheet 16, to form an air retaining volume 22 between the base sheet 16 and the cover 18. Preferably the 20 external surface of cover 18 is white for maximum reflectivity of solar radiation and is made of a UV stabilised material. In this embodiment, the submerged surface areas 14 are provided as a number (six for the hexagonal module) of 25 sector-shaped generally planar sheets 24. The sheets are maintained at a separation below the base sheet 16 by - 11 elements 26, substantially normal to the surface of base sheet 16, attached at their outer ends to the edges 20 of base sheet 16. The inner ends of the sector-shaped sheets 24 in this embodiment, are supported by a cylindrical 5 element 28 depending from the centre of the base sheet 16. The elements 26 and the central cylindrical element 28 project an equal distance below the base sheet 16 so that the sector-shaped sheets 24 are parallel to the base sheet 16. Preferably, the elements 26, sheets 24 and central 10 cylindrical element form an integral structure. Gaps 30 are left between each of the sector-shaped sheets 24, and between adjacent elements 26 so that water may flow through the space defined by the elements 26, sector-shaped sheets 24 and the underside of the base sheet 15 16. Second Preferred Embodiment In a second preferred embodiment of the invention, with reference to Figures 5, 6 and 7, an evaporation reduction module 100 also comprises a floatation chamber 20 112 and submerged surface areas 114. As for the first preferred embodiment above, module 100 comprises a floatation chamber 112 and cover 118. In this embodiment also, floatation chamber 112 is formed of a semi-rigid polygonal (preferably hexagonal) base sheet 116 with the 25 cover 118 sealingly attached to the edges 120 of base sheet 116.

- 12 In this embodiment, submerged surface areas 114 again comprise a number, preferably, though not necessarily six, of sheet segments 124 suspended below base sheet 116. Sheet segments 124 are supported at both their outer and inner 5 ends by supporting elements 126 and 127 respectively, substantially normal to the underside of base sheet 116. Elements 126 and 127 extend equally below the underside of floatation chamber 112 so that sheet segments 124 are parallel to the base sheet 116. Preferably, each sheet 10 segment 124 and its supporting elements 126 and 127, form an integral structure. The arrangement allows water to flow freely through gaps 130 between the structures formed by the sheet segments 124 and elements 126, and between the underside of 15 floatation chamber 112 and the submerged surfaces 114. Third Preferred Embodiment In a third preferred embodiment of the invention with reference to Figures 8 to 11, an evaporation reduction module 200 is formed of a floatation chamber 212 as 20 described for the above embodiments, and submerged surface areas 214. In this embodiment the surface areas 214 comprise one contiguous sheet of material 224, substantially coextensive in area with that of the polygonal base sheet 216 of floatation chamber 212. In at 25 least one preferred form of this embodiment, contiguous sheet 224 is convex as shown Figure 10 so that the central - 13 portion of sheet 224 is closer to the underside of the floatation chamber than it is at the peripheries. Contiguous sheet 224 is provided with a number of apertures 225 to allow water to flow into and out of the 5 space between sheet 224 and the underside of base sheet 216. Contiguous sheets 224 is suspended below floatation chamber 212 by supporting elements 226 at each of the corners of polygonal base sheet 216. Elements 226 extend from each corner, part way along adjacent polygonal base 10 sheet 216 edges 220, so as to leave openings 230 between the element 226 at a given corner and the elements 216 at adjacent corners. Fourth Preferred Embodiment In this further preferred embodiment with reference to 15 Figures 12 to 16, an evaporation reducing module 300, again comprises an upper floatation portion 312, and submerged surface areas 314. However in this preferred embodiment, the floatation portion 312 is divided into a number, preferably six, floatation chambers 313, as best seen in 20 Figures 15 and 16. Submerged surfaces 314 are arranged as previously described in the Third Preferred Embodiment above, and shown in Figure 13. In this preferred embodiment, floatation portion 312 is again formed with a shallow dome 25 shape but has a circular perimeter 315, with the floatation portion 312 mounted to a hexagonal base sheet 316.

- 14 In at least one preferred form in which floatation portion 312 is divided into six separate floatation chambers 317 as shown in Figures 15 and 16, at least some of these chambers 317 may be filled with a foam to provide 5 floatation even if some damage to the cover 318 were to occur. Submerged surfaces 314 are suspended from base sheet 316 by side panels 319, each of which is provided with a generally rectangular opening to allow flow of water 10 between the underside of base sheet 316 and surfaces 314. The closed portions 320 of side panels 318 at each of the corners of the hexagonal structure, are preferably provided with holes 322. Holes 322 allow the modules 300 to be strung together by ropes or cables (not shown) if desired. 15 Floatation of module 300 is arranged so that base sheet 316 is at or just below the water line, so that side panels 319 are substantially submerged. With these panels below the water line, collisions between adjoining modules in choppy and windy conditions is buffered by water between 20 the colliding surfaces. In this embodiment, the underside of sheet 324 forming submerged 314, is provided with an array of keel or fin like structures 326 as shown in Figures 13, 14 and 16. Domed cover 318 may be provided with grooves 328, 25 corresponding in position to the fin-like structures 326. As well as providing further stabilizing of module 300, - 15 fin-like structures 326 and grooves 328 allow a number of modules 300 to be stacked one on top of the other for transport and storage. Fifth Preferred Embodiment 5 With reference now to Figures 17a to 17c, in this further preferred embodiment, an evaporation reduction module 400 again includes a floatation chamber 412 similar to those described in the previous embodiments above. In this instance however the submerged surface areas 414 10 comprise the upper surface of a generally disc or polygon shaped member 413 attached to a central mast depending from the base sheet 416 at the underside of the floatation chamber 412. 15 In Use The buoyancy of each of the evaporation reduction modules in the above described embodiments is arranged so that the modules float with the base sheet just below the level of the water surface as can be seen in Figure 1. The 20 edges of the base sheet (16; 116; 216) and edges (20; 120; 220) of the cover are then preferably at or just below the water surface, so that the only projection of the module above the water surface is the smoothly domed shape of the cover. The cover therefore presents minimal exposure to 25 laminar wind forces acting along the surface of the water.

- 16 In each of the embodimentsr the submerged surface areas (14; 114; 214; 314 and 414) which are substantially parallel to the underside of the floatation chamber, act to stabilise and secure the modules in the water. There is 5 sufficient submerged surface area interacting with water flowing between the underside of the floatation chamber and the submerged surface areas, to provide resistance to any tendency of a module to be lifted or blown out of the water by a either wind or wave action or a combination of these. 10 At the same time, although the water volume at any time between the submerged surface areas and the underside of the floatation chamber acts in effect as ballast, the water is not retained but, being relatively free to flow into and out of this space, does not become stagnant, as is the case 15 when water is used as ballast within an enclosed space. It will be appreciated that under conditions of choppy surface and wind, some portion of the underside of a floatation chamber may break the water surface and become exposed to wind. Although water can escape from the space 20 between the submerged surface areas and the floatation chamber, the elements supporting the submerged surfaces act to slow such transfer of water, sufficient to prevent the flipping over of the module. The above describes only some embodiments of the 25 present invention and modifications, obvious to those - 17 skilled in the art, can be made thereto without departing from the scope of the present invention.

Claims (21)

1. A water evaporation reduction module for an exposed water surface; said module comprising at least one air retaining floatation chamber; said module further 5 comprising submerged surface areas suspended below an underside of said chamber; said submerged surface areas substantially parallel to said underside; said surface areas reacting against water flowing between said surface areas and said underside to resist 10 lifting of said module from a water surface when said module is in use.

2. The module of claim 1 wherein said at least one floatation chamber comprises a generally planar semi rigid base sheet and a generally dome-shaped cover 15 sealingly attached to said base sheet; space between said generally dome-shaped cover and said base sheet enclosing a volume of air sufficient to provide floatation to said module.

3. The module of claim 2 wherein said base sheet has a 20 polygonal shape.

4. The module of claim 3 wherein said polygonal shape is hexagonal.

5, The module of claim 3 or 4 wherein said submerged surface areas comprise upper surfaces of a plurality - 19 of separate sheet segments radially arranged relative to the centre of said polygonal base sheet; inner ends and outer ends of said sheet segments connected to said underside of said chamber by respective inner and 5 outer supporting elements; said supporting elements substantially normal to an underside of said base sheet.

6. The module of claim 5 wherein said sheet segments and said supporting elements form structures at said 10 underside of said base sheet; said structures separated by gaps to allow flow of water through said gaps, and between said underside and said upper surfaces of said sheet segments.

7. The module of claim 5 or 6 wherein said elements at 15 said inner end and said outer end of a said sheet segment are integral with said sheet segment.

8. The module of any one of claims 5 to 7 wherein a said supporting element at said outer end of a said sheet segment is attached at an edge of said polygonal base 20 sheet; said sheet segment attached at an inner end to a cylindrical element depending from said centre of said underside of said base sheet; said supporting element at said outer end and said cylindrical element at said inner end extending equally below said - 20 underside of said chamber so as to suspend said sheet segment substantially parallel to said underside.

9. The module of any one of claims 3 to 8 wherein said submerged surface areas comprise an upper surface of a 5 sheet of material; said sheet of material generally coextensive in area with said polygonal base sheet; said sheet of material suspended below said underside of said chamber by supporting elements at each corner of said polygonal base sheet; each said supporting 10 element extending part way along adjacent polygonal sheet edges from a said corner so as to leave openings between a supporting element at a given corner and supporting elements at adjacent corners.

10. The module of claim 9 wherein said sheet of material 15 is provided with apertures; said apertures adapted to allow flow of water through said apertures and through said openings between said supporting elements at said corners.

11. The module of claim 9 or 10 wherein said sheet of 20 material suspended below said underside of said module is substantially planar and parallel to said underside.

12. The module of claim 9 or 10 wherein said sheet of material suspended below said underside of said module - 21 is convex; a central portion of said sheet of material being closer to said underside than peripheral portions of said sheet.

13. The module of claims 1, 2 or 3 wherein said submerged 5 surface areas comprise the upper surface of a generally disc shaped member attached to a central mast depending from an underside of said floatation chamber.

14. The module of any one of claims 1 to 13 wherein 10 buoyancy of said module is arrange so that said module floats on a said water surface with said cover substantially exposed above said water surface; edges of said cover submerged below said water surface.

15. The module of any one of claims 2 to 14 wherein said 15 generally dome shaped cover is adapted to minimise wind resistance to laminar wind forces at said water surface.

16. The module of any one of claims 1 to 15 wherein lifting forces tending to lift said module are forces 20 generated by wind and wave action at said water surface.

17. The module of any one of claims 1 to 16 wherein said module includes six floatation chambers. - 22

18. The module of any one of claims 1 to 17 wherein at least one of said at least one floatation chamber is filled with foam.

19. A method of reducing water evaporation from a body of 5 water; said method including the steps of: (d) providing a plurality of floating modules; each of said modules comprising at least one floatation chamber and submerged surface areas, (e) shaping said modules so as to minimise uncovered 10 water surface when said modules are clustered together, (f) suspending said submerged surface areas below said floatation chamber to allow flows of water between an underside of said chamber and said surface areas, 15 said water and said submerged surface areas interacting to provide resistance to lifting forces acting on said modules.

20. A method of providing resistance to dislodgement of an evaporation reduction module from the surface of a 20 body of water by wind and wave action; said method including the steps of: (c) providing said evaporation reduction module with a generally dome-shaped cover, - 23 (d) suspending submerged surface areas below said module, wherein said submerged surface areas are generally parallel to an underside of said module with water 5 flowing between said underside and said submerged surfaces.

21. A water evaporation reducing module as herein described and with reference to the accompanying drawings, and in particular to Figures 17a to 17c. 10