Field of the Invention

The present invention relates to a floating modular cover for reducing water loss due to evaporation particularly in large water storages.

Background to the Invention

In regions of high evaporation and seasonal rainfall, water loss from large open storages due to evaporation is high and difficult to control.

Evaporation control in relatively small areas of a few hectares or less is usually achieved with a cover over the total surface which is anchored at the edges. However, such covers are typically only used to reduce water loss from evaporation in limited areas due to their inherent dynamic inflexibility on the water surface, the need to be affixed to the perimeter of the water storage and the need to be held down during high winds.

International Patent Application No. WO 98/12392 discloses a modular cover for large areas consisting of a flat polygonal floating body where the faces of the floating body have partly submerged vertical walls with lateral edges. The device has an arched cover with a hole in the top cover for air exchange. Although the wall depth is large underwave and local high surface wind conditions, the covers can be blown off the water surface and overturned.

International Patent Application No. WO 2006/010204 discloses a floating modular cover for a body of water consisting of a series of modules. Each module is formed from an upper shell and a lower shell which are sealed together to form a central chamber and one or more peripheral flotation cells. One or more openings are provided in the lower shell to allow the ingress of water into the chamber for ballast. One or more openings are also provided in the upper shell to allow air inflow into and out of the chamber depending upon the water level within the chamber. The provision of a closed chamber ensures that water within the chamber functions as ballast preventing the module from being easily blown around or overturned. This difference provides a significant advantage over the arrangement disclosed in International Patent Application WO 98/12392. The size of the modules are chosen too provide a large surface cover. The periphery of each module has a polygonal shape, the number of sides being determined by a desired application to allow the packing of the modules on the water surface. For example, the modules may have a hexagonal or octagonal shape. When placed to float on a body of water, the modules will tend to accumulate in an area dictated by the prevailing winds. The area of coverage will depend upon the number of modules of used on the body of water. The shape of the individual modules and the movement between them will conserve water storage by limiting evaporation of the water without interfering with the aqua culture because sufficient area will be exposed to allow oxygenation of the water.

However, it has been found that the modules forming the floating modular cover disclosed in International Patent Application No. WO 2006/010204 are subject to stress and cracking in use. Furthermore, the manufacture and assembly of the modules has been found to be complex, expensive and time consuming. The upper and lower shells are difficult to assemble, and there is currently no sealing technique that can achieve a hermetic seal and provide integrity to the flotation cells or the modules during the life of the product. Moreover, the stress cracking to which welded or glued products are subject causes leaks over a period of time making the product ineffective.

It would be desirable to provide a module for use in a floating modular cover for a body of water which retains structural integrity and functionality for considerably longer than the modules disclosed in International Patent Application No. WO 2006/010204. Moreover, it would be desirable to for the modules to be less expensive, less complex and quicker to manufacture and/or assemble.

It would also be desirable to provide a module for use in a floating modular cover for a body of water which ameliorates or overcomes one or more disadvantages of inconveniences of known modules for use in such floating modular covers.

Brief Description of the Invention With this in mind, one aspect of the present invention provides a module forming part of a floating modular cover for a body of water. The module includes and upper shell, a lower shell and a chamber defined by the upper and lower shells. One or more water ingress openings are provided in the lower shell to allow ingress of water into the chamber for ballast. One or more air openings are also provided in the upper shell to allow air flow into and out of the chamber depending on the water level within the chamber. A plurality of flotation cells is provided for flotation of each module.

Importantly, one or more first securing openings are provided in the lower shell, and one or more second securing openings are provided in the upper shell. Each flotation cell is insertable through a pair of the first and second securing openings, and cooperates with first shell wall portions surrounding each pair of first and second securing openings to thereby retain the module in an assembled state.

In such an arrangement, the need to form sealed flotation cells in or during the assembly process in avoided. Moreover, the flotation cells function both to ensure flotation of the module and also locate and lock the two shells together in an assembled state. This avoids the rigidity which comes from hermetically sealing (for example by welding and chemical bonds) the shells together, which can result in fracturing or cracking of the flotation cells and the shells. Fracturing or cracking of the flotation cells results in water ingress which can cause the module to sink below an ideal operating position.

Conveniently, the upper and lower shells may be formed so that the first shell wall portions surrounding each pair of first and second securing openings are flush against each other when the module is in the assembled state.

The first and second securing openings may be holes, and may be conveniently cut by laser or router as required.

Each flotation cell may include a groove running around the flotation cell between opposing shoulders, the shoulders acting to retain there between the first shell wall portions. Preferably, the shoulders are disposed so as to bear against the first shell wall portion and bias the upper and lower shells toward each other when the module is in an assembled state.

Both the groove and the openings may be circular, so as to maximise the strength and resistance to damage or tearing of the flotation cells and first shell wall portions.

Each flotation cell may include one or more polygonal heads. In one convenient arrangement, each flotation cell may include a polygonal head at each extremity, for example in the form of a circular, triangular, hexagonal or octagonal shape. The ribbing created in the transition from the polygonal heads to the circular centre of the flotation cell provides structural strength to the flotation cell and resists against deformation of the cell.

Conveniently, each flotation cell may be separately moulded as a sealed unit. Whilst the flotation cells may be filled with foam or like material, preferably each flotation cell is simply hollow and filled with air.

In order to provide some additional structural stability to the module, the upper and lower shells, when in an assembled state, may be spot joined or clipped at one or more positions. The spot joining positions may be between the flotation cell locations.

Each module may have a plurality of sides and the spot joining or clipping positions may be located on each side or on each corner between adjacent sides.

The upper and lower shells may be formed to provide second cell wall portions at each spot joining or clipping location which are adapted to be flush against corresponding second shell wall portions on the other of the upper and lower shells when the module is in an assembled state. The upper and lower shells may be spot joined or clipped by any convenient means, such as by application of a heat stake, laser, ultrasonic or vibrational welding or any convenient plastic assembly technique.

Conveniently, the upper and lower shells may be identical. The upper and lower shells may include a polygonal circumferential shape, each shell including projections extending towards the other shell, when the module is in an assembled position, from alternative faces so as to cover the juncture between the two shells.

Another aspect of the invention provides a floating modular cover for a body of water, the cover including a plurality of modules as described hereabove.

A further aspect of the invention provides a shell forming part of a module as described hereabove.

A still further aspect of the invention provides a flotation cell forming part of a module as described here above.

Brief Description of the Drawings

Various aspects and features of the invention will be more fully understood with reference to the drawings in which:

Figure 1 is a perspective view of one embodiment of a module forming part of a floating modular cover for a body of water;

Figure 2 is an exploded perspective view of the module shown in Figure 1 ;

Figure 3 is a plan view of a portion of the module shown in Figure 1 ;

Figure 4 is a side view of one embodiment of the module depicted in Figure 1 taken through a section A-A;

Figure 5 is a side view of an alternative embodiment of the module depicted in Figure 1 taken through a section A-A;

Figure 6 is a perspective view of part of the module shown in Figure 1 ;

Figure 7 is a perspective view of another portion of the module shown in Figure 1 ;

Figure 8 is an exploded view of an alternative embodiment of the module depicted in Figure 2;

Figure 9 is a cross-sectional view of a first portion of the module of Figure 8; Figure 10 is a cross-sectional view of a second portion of the module of Figure 8; and

Figure 1 1 is a perspective view of a floating modular cover including a number of modules of the type depicted in Figure 1.

Detailed Description

Referring now to Figures 1 and 2, there is shown generally a module 10 forming part of a floating modular cover for a body of water, such as a dam, pond or golf course water hazard. The module 10 includes an upper shell 12 and a lower shell 14. When in an assembled state as depicted in Figure 1 , the upper shell 12 and lower shell 14 define a chamber 16 therebetween. The lower shell 14 includes one or more water ingress openings (not depicted) to allow ingress of water into the chamber 16 for ballast when the module is located on a body of water. Similarly, the upper shell 12 includes one or more air openings, such as the openings 18 to 22 shown in Figure 1 , to allow air and or water to flow into and out of the chamber 16 depending upon the water level within the chamber. The upper and lower shells are depicted as having a hexagonal circumferential shape, although it will be appreciated that in other embodiments one or both shells may have another polygonal or non-polygonal circumferential shape. It will also be appreciated that the module can be inverted in water so that the upper and lower shells are inversed. In this case, the water ingress openings become the air openings and vice versa.

The upper and lower shells 12 and 14 are maintained in a substantially fixed relation to each other by means of corresponding securing openings at or near the periphery of the upper and lower shells, through which is inserted a series of flotation cells 24 to 34. Accordingly, first securing openings, such as those referenced 36 and 38 in Figure 2, are provided in the lower shell 14, whilst second securing openings, such as those referenced 40 to 50 in Figure 2, are provided in the upper shell 12.

Each flotation cell, such as that referenced 26 in Figure 2, is insertable through a pair of first and second securing openings, such as the first securing opening 38 and the second securing opening 42. The flotation cell cooperates with first shell wall portions surrounding each pair of first and second securing openings to thereby retain the module 10 in an assembled state. Exemplary first shell wall portions 54, 56 and 58 are depicted in Figures 3 and 4. Flotation cells can be varied in size and shape to enable the module to take additional weight and a load and/or change the height at which the module floats in water.

Figure 3 shows a plan view of a portion only of the upper shell 12. This figure depicts a first shell wall portion 54 surrounding the second securing opening 46. Figure 4 depicts first shell wall portions 56 and 58 respectively surrounding the second securing opening 42 and first securing opening 38 in Figure 1.

Conveniently, the upper and lower shells 12 and 14 are formed so that the first shell wall portions, such as the shell wall portions 56 and 58, surrounding each pair of first and second securing openings, such as securing openings 38 and 42, are flush against each other when the module is in the assembled state. Whilst this facilitates the insertion of the flotation cell through the pair of first and second securing openings and assists in providing structural integrity to the chamber 16, it will be appreciated that in other embodiments of the invention the first shell wall portions surrounding the pair of securing openings through which the flotation cell is inserted need not necessarily be flush against each other.

As can be seen from Figures 2 and 3, the first and second securing openings formed respectively in the lower shell 14 and upper shell 12 may be holes. In other words, the first shell wall portions may entirely surround a relevant securing opening in other embodiments of the invention though, a slot may be provided between one or more of the securing openings and the exterior or the module 10 in order to facilitate insertion of the flotation cell. However, in such an arrangement it is more likely that the flotation cell will come free from the module when in use.

As can be best seen in Figure 4, the illustrative flotation cell 26 includes a groove 60 running around the flotation cell between opposing shoulders 62 and 64. The shoulders 62 and 64 act to retain therebetween the first shell wall portions 56 and 58. As depicted in the embodiment shown in Figure 4, the shoulders 62 and 64 have slopping shoulders which are disposed so as to bear against the first shell wall portions 56 and 58 and bias the upper and lower shells 12 and 14 towards each other when the module 10 is in the assembled state. This arrangement assists in providing firm engagement of the upper and lower shells 12 and 14 and in the flotation cell not ejecting itself from the securing openings. Both the groove 60 and the first and second securing openings 38 and 40 into which the flotation cell 26 is inserted are preferably circular. This acts to improve the strength of both the securing openings and the flotation cell, and makes both less prone to damage or tearing.

Figure 5 shows an alternative embodiment in which shoulders 63 and/or 65 are formed with a sharp edge running substantially parallel to the surfaces of first shell wall portions 57 and 59 so as to permit a limited amount of movement of the shell wall portions towards and away from each other within groove 61.

In order to optimise the structural strength along their entire length, each flotation cell preferably includes one or more polygonal heads. For example, the flotation cells 24 to 34 each include triangular shaped heads at one or both extremities. An alternative configuration is depicted in Figure 6, which shows a flotation cell 70 including an octagonal shaped head 72. In each case, ribs project from each of the vertices of the polygon shape on the head of the flotation cell towards the centre of the flotation cell where the groove is located so as to improve the resistance to deformation of the flotation cell. The cross section of the flotation cells 24 to 34 and 70 gradually vary from a polygonal shape at each extremity to a circular shape at the centre.

The upper and lower shells 12 and 14 are preferably manufactured from polymer or other plastics material by injection or blow moulding, although any other convenient material, manufacturing process or technique may be adopted.

The first securing holes formed in the upper and lower shells may be conveniently be cut by laser for speed and accuracy, and removed portion of material chipped and fed back into the moulding process to minimise waste. The manufacture of the flotation cell shells separately from the upper and lower shells eliminates the need to provide an air-tight seal between the upper and lower shells to thereby form the flotation cells as an integral component of the sealed shell.

The flotation cells may be manufactured by blow moulding or injection moulding and ideally should be sealed to create a hollow water-tight unit. In other embodiments though, the hollow space within the flotation cell could be filled with foam or like buoyant material. Alternatively, the flotation cell could be manufactured so that it was solid throughout and formed from a naturally buoyant material. However, these variations are likely to increase the cost and complexity of manufacture.

Whilst insertion of the flotation cells through pairs of first and second securing openings acts to retain the module in an assembled state, it may nevertheless be desirable to provide additional rigidity to the module by spot joining the upper and lower shells at one or more positions when the module is in an assembled state. Spot joining may be carried out by any well known plastic assembly technology, including ultrasonic welding, clips or the application of heat stakes. Various other plastic assembly technologies will be known by persons of ordinary skill in the relevant field of technology.

In order to facilitate their spot joining, the upper and lower shells 12 and 14 are each provided with second shell wall portions, such as the shell wall portions 74 and 76 depicted in Figure 7. Each second shell wall portion may be formed to be flush against a corresponding second shell wall portion on the other of the upper and lower shells when the module 10 is in the assembled state.

Preferably, the spot joining positions are located between the flotation cell locations in order to evenly distribute the positions at which the upper and lower shells are held together. In the above described example, each module is in the form of a hexagon and flotation cells are located along each of the six sides of the hexagon. In other embodiments, the periphery of the module may have another polygonal shape or any other desirable form. Moreover, in the above described embodiment, the spot joining positions are located between the flotation cell locations in each corner between adjacent sides of the hexagonal form of the module. It will be appreciated that in other embodiments of the invention, the spot joining positions may be located on each side of the polygonal form of the module or indeed at any other convenient location or locations around the periphery of the module.

The upper and lower shells 12 and 14 in the above described module are identical. Conveniently, this requires only one shell form to be manufactured. Pairs of identical shells are then able to be assembled by insertion of the flotation cells through the pairs of first and second securing openings and optionally by use of additional spot joins around the periphery of the shells in order to form the assembled module.

In an alternative embodiment depicted in Figure 8, upper and lower shells 80 and 82 each include projections extending from alternate faces of their hexagonal circumferential shapes. In this figure, two such projections 84 and 86 are shown extending towards the lower shell 82, whilst one such projections 88 is shown extending towards the upper shell 80. When the module is assembled, the projections 84 to 88 act to cover the juncture between the two shells and minimise the instantaneous discharge of ballast water from between the two shells. It will be appreciated that the upper and lower shells may be identical, and that by inverting and rotating one shell (in this case by 60 degrees) that shell can be positioned so as to engage or mate with another shell. The extent to which the projections from one shell extend towards the other shell may vary. Figure 9 shows exemplary shell wall portions 90 and 92 respectively forming part of the shells 80 and 82. In this case, the projection 84 may include a first part 94 extending towards the lower shell 82 so as to cover the thickness of the shell wall portion 92 when the module is in an assembled state. However, as seen in Figure 10, that same projection 84 may include a second part 96 extending towards the lower shell 82 to a greater extent away from the shell wall portions.

Once assembled, a series of individual modules, such as the modules 100 to 106 are placed on the surface of a body of water and together form a floating modular cover 108, as seen in Figure 1 1 to reduce water loss due to evaporation from that body of water. The ease with which the module 10 is able to be assembled facilitates the assembly of the module on site at the location in which the floating modular cover is intended to be used. Rather than being required to assemble each module at a central manufacturing location, and then transport the assembled modules to a desired location for use, the unassembled shells are able to be stacked and transported to a particular site, together with a supply of flotation cells.

Assembly of the modules can take place quickly and conveniently next to the body of water upon which the floating modular cover is intended to be placed. A relatively inexpensive and easy to operate ultrasonic welding, clip or heat staking piece of equipment is the only piece of apparatus that may be required if additional spot joins are required.

While the present invention has been described in conjunction with a limited number of embodiments, it will be apparent to those skilled in the art that many alternatives, modifications and variations are possible in light of the foregoing description. The present invention is intended to embrace all such alternatives, modifications and variations as may fall within the spirit and scope of the invention as disclosed.