AU2002248975A1 - An evaporation control device for a body of water - Google Patents

Description

"An evaporation control device for a body of water"

Field of the Invention

The present invention relates to a device for controlling evaporation of a body of water, such as dams and swimming pools. Still further, the present invention relates to a structure which can be readily assembled on site to a shape and size that matches the size and shape of the body of water.

Background of the Invention

Loss of water from water storage bodies due to evaporation often causes inconvenience, economic loss and undesirable changes in concentration of solutes within the body of water. Irrigation and stock reservoirs, dams and swimming pools are among the bodies of water that are adversely affected by such evaporation.

The accumulation of debris from plants and animals in swimming pools also causes inconvenience, clogging of filtration systems and potential damage. Loss of heat from heated pools due to lack of use of insulating covers also results in increased heating expense.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Summary of the Invention

Throughout this specification the word "comprise", or variations such as

"comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. The present applicant has recognised the shortcomings of current evaporation control devices and practices in the prior art and accordingly has sought to provide a device for controlling or at least reducing the rate of evaporation from a body of water. The present applicant has also recognised the shortcomings of current swimming pool and water body cover devices and practices in the prior art and accordingly has sought to provide an improved device and method of manufacture thereof.

According to a first aspect, the present invention is a laminated cover for reducing the rate of evaporation of a body of water, the cover comprising at least one first layer of material that is relatively heat reflecting and at least one second layer of material that is relatively light absorbing.

In a first embodiment, the cover is preferably adapted to be positioned above the body of water with the relatively heat reflecting first layer facing upwardly.

In a further embodiment, the cover can include at least one intermediate layer. The at least one intermediate layer can be formed from a layer of relatively light absorbing material. The at least one intermediate layer can be more or less light absorbing than the second layer. In another embodiment, the at least one intermediate layer can be formed of the same material as the second layer. In a further embodiment, the cover can include two, three, four or a greater number of intermediate layers. The at least one intermediate layer can have a thickness of between about 30 microns and 1.5mm, more preferably between about 40 and 750 microns, more preferably still between about 50 microns and 150 microns, and most preferably about 80 microns.

In one embodiment, the at least one first layer is formed of planar film of substantially constant thickness. In another embodiment, the thickness of the at least one first layer can vary. The at least one first layer preferably has a thickness between about 50 and about 350 microns, more preferably between 75 and 150 microns and more preferably still about 100 microns. The at least one first layer is preferably white or a similar colour. The layer can have a white coating or be intrinsically formed from a white material. The at least one first layer can comprise a polymeric film material. The polymeric film can comprise a single polymer, a copolymer or a polymer blend. Examples of materials used for the first layer can include high density polyethylene, low density polyethylene, polypropylene, polyvinylchlohde, ethyl vinyl acetate, polyamide and polyethylene teraphthalate. The polymeric film preferably has one or more additives to stabilise or at least reduce the rate of film degradation due to exposure to ultra-violet (UV) radiation.

The at least one second layer can include a plurality of sealed cavities disposed in a plane. The plurality of sealed cavities with entrapped air provides thermal insulation and bouyancy. Each of the sealed cavities preferably extend outwardly from a substantially flat base. The cavities each preferably extend outwardly a substantially equal distance from the flat base. The cavities can extend outwardly by a distance from the base of between about 0.5 and 10mm, more preferably about 3mm and 7mm, and most preferably about 4mm. The polymeric film used in the at least one second layer preferably has a thickness between about 100 and 750 microns, more preferably between 150 and 350 microns, and most preferably about 250 microns. Examples of shapes of sealed cavities can include squares, circles, rectangles, ellipses and triangles.

Each sealed cavity is preferably substantially circular with a substantially flat base. Each cavity preferably has a diameter between about 5mm and 25mm, more preferably between 5mm and 20mm, and most preferably about 15mm. Each cavity can be spaced from each of its adjacent cavities by an approximately equal minimum distance. The distance can be between about 1 mm and 10mm, more preferably between about 1 mm and 5mm, and most preferably about 2mm.

In one dimension, hereinafter "the x-dimension", the sealed cavities can be linearly aligned. In another dimension, hereinafter the "y-dimension", the sealed cavities can be off-set from its immediate neighbours in the y- dimension. In this case, every alternate sealed cavity in the y-dimension is preferably longitudinally aligned. In one embodiment, the at least one second layer can comprise a layer of what is commonly known as "bubble wrap". The at least one second layer is preferably black or a similar colour. The layer can have a black coating or be intrinsically formed from a black material. The light absorbing nature of the at least one second layer serves to prevent or substantially prevent light transmission through the cover. This preferably helps to slow or stop photosynthesis in the body of water, and heating of the body of water.

The at least one second layer can be formed from polymeric film material. The polymeric film can comprise a single polymer, a copolymer or a polymer blend. Examples of materials used for the second layer can include high density polyethylene, low density polyethylene, polypropylene, ethyl vinyl acetate, polyvinylchloride, polyamide and polyethylene teraphthalate. The polymeric film preferably has one or more additives to stabilise or at least reduce the rate of film degradation due to exposure to ultra-violet (UV) radiation.

When incorporated in the laminate, the at least one intermediate layer is preferably black or a similar colour. The intermediate layer can have a black coating or be intrinsically formed from a black material.

The at least one intermediate layer can be formed from polymeric film material. The polymeric film can comprise a single polymer, a copolymer or a polymer blend. Examples of materials used for the intermediate layer can include high density polyethylene, low density polyethylene, polypropylene, ethyl vinyl acetate, polyvinylchloride, polyamide and polyethylene teraphthalate. The polymeric film of the intermediate layer can have one or more additives to stabilise or at least reduce the rate of film degradation due to exposure to ultraviolet (UV) radiation.

In a still further embodiment, the intermediate layer or layers may act as gas and/or water barriers.

The laminate can be formed by thermal bonding, co-extruding or ultrasonic welding. Other methods including adhesives may be utilised to adhere the plurality of layers together in certain instances. In a further embodiment, the cover is preferably substantially buoyant and will float if placed on the surface of a body of water.

In a still further embodiment, the laminate has a plurality of holes formed therein. The holes can be regularly or irregularly spaced throughout the laminate. The holes preferably have a diameter less than about 20mm, however, other dimensions can be readily envisaged. The holes can act to allow escape of gases built up under the laminate through the cover and to allow rain water to pass through the cover.

In yet still another embodiment, the laminate includes a weight means that stops the cover from lifting off the body of water. The weight means can be dead weights below, within or above the laminate. The weight means can be a is a tubular member filled with water or another liquid or slurry. The tubular member can be above, below or within the laminated cover. The tubular member can be formed integrally with the laminated cover or formed separately from the cover.

In a further embodiment, the laminate cover can have at least one outer edge. Where the laminated cover is substantially rectangular or square in shape, the laminate cover will have parallel or substantially parallel first and second ends, and parallel or substantially parallel first and second side edges.

The first side edge of a first formed laminate can be adapted to releasably or non-releasably engage with the second edge of another formed laminated cover positioned in side-to-side relationship with said first formed cover. In a still further embodiment, the first end of a first formed laminate can be adapted to releasably or non-releasably engage with the second end of another formed laminated cover positioned in top-to-tail relationship with said first formed cover. In one embodiment, the first edge of a first formed laminate can have an engagement means adapted to releasably or non-releasably engage with a complementary engagement means on the second edge of another laminated cover. A similar engagement means can be provided at the first end that is adapted to engage with a complementary engagement means on the second end of said other cover. In another embodiment the engagement means can comprise polymeric zip-type components. This allows a plurality of covers to be formed and positioned to cover any sized body of water.

In one embodiment, a single cover can be used to cover a body of water. In another embodiment, more than one cover may be required to cover a particular body of water. In a still further embodiment, it may be decided to only cover a portion of a body of water.

According to a second aspect, the present invention provides a method for forming a laminated cover for reducing the rate of evaporation of a body of water, the method including the steps of:

(i) forming at least one first layer of material that is relatively heat reflecting;

(ii) forming at least one second layer of material that is relatively light absorbing; and

(iii) bringing the at least one first layer and at least one second layer into face-to-face abutment to form a laminate.

It will be appreciated that in the above aspect, steps (i) and (ii) could be performed in any order or simultaneously. The first and second layers defined in the above method can have any one or more of the features of these layers described above.

In a further embodiment, the method can include an additional step of forming at least one intermediate layer, as defined herein, that is then incorporated into the laminate in step (iii).

According to a third aspect, the present invention is a component structure of a cover for a body of water, the structure comprising a planar member having a first edge and at least a second edge, the first edge having an engagement means along at least a portion of its length and the second edge having an engagement means complementary to that of the first edge engagement means along at least a portion of its length, the first edge engagement means being engageable with a complementary second edge engagement means of a first other planar member and the second edge engagement means being engageable with a first edge engagement means of a second other planar member.

According to a fourth aspect, the present invention provides a method of forming a cover for a body of water comprising the steps of:

(i) obtaining at least two component structures arranged to be engaged together to form a cover for a body of water;

(ii) determining the dimensions of the body of water; and (iii) engaging the component structures to form a cover that at least substantially matches the dimensions of the body of water defined in step (ii).

In the third and fourth aspects, the planar member will have a first edge and a second edge. Where the planar member is substantially rectangular or square in shape, the planar member will preferably have parallel or substantially parallel first and second side edges. The first side edge of a first planar member is adapted to engage with the second edge of another planar member positioned in side-to-side relationship with said first planar member.

In a further embodiment, the planar member can have parallel or substantially parallel first and second ends. The first end of a first planar member can be adapted to engage with the second end of still another planar member positioned in top-to-tail relationship with said first planar member.

The first edge of a first planar member has an engagement means, or first edge engagement means, adapted to engage with a complementary engagement means on the second edge, or the second edge engagement means, of another planar member. A similar engagement means can be provided at the first end of the planar member that is adapted to engage with a complementary engagement means on the second end of still another planar member.

In another embodiment of the third and fourth aspects, the above defined engagement means can be a releasable engagement means. Examples of engagement means can include zipping devices, snap-lock devices, interlocking mechanisms, clips and pins. The respective engagement means are preferably a polymeric zip-type interengagement means. The polymeric zip-type interengagement means can be formed from a single polymer, a copolymer, a polymer blend or a co- extrusion. The polymeric zip-type interengagement means preferably has one or more additives to stabilise or at least reduce embrittlement and degradation due to exposure to ultra-violet (UV) radiation. The respective polymeric engagement means can be attached to the planar members by adhesive bonding, thermal fusing, flame lamination, ultrasonic welding, extrusion bonding, sewing, riveting, pressure sensitive tapes or heat reactivatable tapes.

A zipping device is used to releasably engage the first edge engagement means and the complementary second edge engagement means. The zipping device is constructed in a manner such that the first edge and second edge engagement means enter the zipping device in an unengaged state and exit the zipping device in an engaged state. The first edge and second edge engagement means can be disengaged or (released) by drawing the first edge and second edge engagement means, whilst in an engaged state, through the zipping device in the opposite direction to the direction used to engage the first edge and second edge engagement means, as described above or by using a peeling action.

In another embodiment of the third and fourth aspects, each planar member is preferably made from at least one layer of a polymeric film. The polymeric film can comprise a single polymer, a copolymer or a polymer blend. Examples of polymeric materials used can include high density polyethylene, low density polyethylene, polypropylene, polyvinylchloride, ethyl vinyl acetate, polyamide and polyethylene teraphthalate. The polymeric film preferably has one or more additives to stabilise or at least reduce the rate of film degradation due to exposure to ultra-violet (UV) radiation.

In an embodiment, the cover is preferably adapted to be positioned above the body of water.

In another embodiment, the planar member is preferably made of at least one layer of a polymeric film, such as that defined above, and at least one layer of an expanded polymeric foam adhered to the at least one polymeric film such that the planar member is buoyant when applied to the surface of a body of water. The at least one layer of polymeric film can be adhered to at least one side of the at least one layer of expanded polymeric foam.

In a further embodiment, the planar member is made from a laminated cover as defined herein as the first aspect of the invention.

The types of bodies of water that can be covered by the covers of the above aspects can be natural or artificial bodies of water. In one example, the body of water can be a swimming pool, eg. a 10m or 50m swimming pool. In another example, the body of water can be a swimming pool of irregular shape. In another embodiment, the body of water can be a dam or a reservoir built on a farming property. The dam may have dimensions up to or greater than 1 ,000,000 square metres. The bodies of water may have symmetrical or non- symmetrical shapes.

Planar members which have the correct geometric shape can be used in conjunction with planar component member of other geometric shapes such that the cover when assembled covers the required dimensions of the body of water.

Brief Description of the Drawings

By way of example only, preferred embodiments of the aspects of the invention are now described with reference to the accompanying drawings, in which:

Figure 1 is a cross sectional view of the laminated cover;

Figure 2 is a schematic view of sealed cavity arrangement;

Figure 3 is an example of laminate cover arrangements;

Figure 4 is an example of an engagement means; Figure 5 is an example of a zipping device;

Figure 6 is a cross-sectional view of an example of a zipping device; and

Figure 7 is transverse sectional views of an example of engagement means being engaged in a zipping device.

Description of the Invention

It should be noted that like reference numerals refer to like features throughout the figures.

One embodiment of a laminate cover according to the present invention is generally depicted in Fig. 1 as 1. The laminate cover 1 includes a first layer 2, a second layer 3 and an intermediate layer 4.

The depicted first layer 2 is formed from a planar polymeric film, of a substantially constant thickness. It will be appreciated that the film 2 could vary in thickness. The polymeric film 2 may be a polymer, copolymer or mixed polymer blend. Examples of materials used for the first layer include high density polyethylene, low density polyethylene, polypropylene, polyvinylchloride, polyamide, ethyl vinyl acetate and polyethylene teraphthalate. The depicted first layer 2 has one or more additives to reduce or stabilise the rate of polymeric film degradation from exposure to ultra-violet (UV) light. The depicted first layer 2 preferably has a thickness between about 50 and about 200 microns, more preferably between 75 and 150 microns and more preferably still about 100 microns. The depicted first layer 2 is coloured white and is formed from an intrinsically of a white material. While not depicted, the first layer 2 can be coloured white by applying at coating or suitable pigment.

The second layer 3 is relatively thermally insulating in comparison with the first layer 2 by virtue of the encapsulation of air within the sealed cavities 5. The second layer 3 is relatively light absorbing in comparison with the first layer 2. Preferably, the second layer 3 is black in colour, and is formed from an intrinsically black material. The light absorbing nature of the second layer 3 serves to prevent or substantially prevent light transmission through the cover. This helps to slow or stop photosynthesis and heating in the body of water when covered by the cover. The second layer 3 is formed from a polymeric material. Examples of materials used for the first layer include high density polyethylene, low density polyethylene, polypropylene, polyvinylchloride, polyamide and polyethylene teraphthalate. Again, the second layer 3 has one or more additives to reduce or stabilise the rate of polymeric film degradation from exposure to ultra-violet (UV) light. The polymeric film used in the second layer 3 preferably has a thickness between about 100 and 500 microns, more preferably between 150 and 300 microns, and most preferably about 250 microns. The second layer 3 has a plurality of sealed cavities 5 disposed in a plane parallel to the plane of the second layer 3. Each of the sealed cavities 5 preferably extend outwardly perpendicular to the plane of the second layer 3 a substantially equal distance from the place of the second layer 3. The cavities 5 can extend outwardly by a distance of between about 0.5 and 10 mm, more preferably between about 1 m and 5 mm and most preferably about 3 mm.

The depicted intermediate layer 4 is formed from a layer of relatively light absorbing material, and in this case of the same material as the second layer 3. While there can be just a single intermediate layer 4, it will be appreciated that there could be two, three, four or more intermediate layers. The intermediate layer can have a black coating or be intrinsically formed from a black material. The at least one intermediate layer 4 can have a thickness of between about 30 and 120 microns, more preferably between 45 and 90 microns, and most preferably about 60 microns. The polymeric film of the intermediate layer 4 can have one or more additives to stabilise or at least reduce the rate of film degradation due to exposure to ultra-violet (UV) radiation. In alternate configurations, the intermediate layer 4 may act as gas and/or water barriers.

The plurality of sealed cavities 5 formed from the second layer 3, are preferably substantially circular, with a substantially flat face 6. The diameter of each cavity is preferably between about 5mm and 25mm, more preferably between 5 mm and 20 mm, and most preferably about 15mm. An example of a schematic configuration of the sealed cavities 5 is shown in Figure 2. Each sealed cavity 5 can be spaced from each of its adjacent cavities by an approximate equal minimum distance. The distance can be between about 1 mm and 10mm, more preferably between about 1 mm and 5mm, and most preferably about 2mm. In a first direction along the plane of the second layer 3, the sealed cavities 5 can be linearly arranged. In a second direction orthogonal to the first direction and parallel to the plane of the second layer 3, the sealed cavities 5 can be off-set from its immediate adjacent cavities in the second direction. In this example, every alternate sealed cavity 5 in the second direction is preferably longitudinally aligned. In one configuration, the second layer 3 can comprise what is commonly known as "bubble wrap".

The laminate cover 1 can be formed by bringing into abutment the first layer 2 of a polymeric material that is relatively heat reflecting with the second layer 3 that is of a polymeric material relatively light absorbing and thermal bonding and/or thermoforming the first layer 2 and the second layer 3. Other methods including adhesives may be utilised to adhere the plurality of layers together in certain instances. The intermediate layer 4 can be included in the laminate cover between the first layer 2 and the second layer 3, and the lamination process performed simultaneously. The second layer 3 can be formed in a manner such that the sealed cavities 5 are formed.

The laminate cover 1 may be adapted to be positioned above a body of water, with the relatively heat reflecting first layer 2 facing upward. The plurality of sealed cavities can be such that the laminate cover 1 is substantially buoyant and will float if placed on the surface of a body of water. The laminate cover 1 can have a plurality of drainage or breather holes 7 passing through the layers of the laminate cover 1 , such that air or gases built up under the laminate cover 1 can escape. The holes can be regularly or irregularly spaced throughout the laminate cover 1. Preferably there is at least one drainage hole in every square metre of laminate cover 1. The drainage hole preferably have a diameter between about 3mm and 35mm, more preferably between about 10mm and 20mm and most preferably about 15mm.

The laminate cover 1 can have at least one outer edge. Where the laminated cover 1 is substantially rectangular or square in shape, as shown in Figure 3 (a) and Figure 3 (b), the laminate cover will have parallel or substantially parallel first and second ends, and parallel or substantially parallel first and second side edges. The first side edge 8 of a first formed laminate 9 can be adapted to releasably or non-releasably engage with the second edge 10 of another formed laminated cover 11 positioned in side-to-side relationship with said first formed cover. In a further example, the first end 12 of a first formed laminate 13 can be adapted to releasably or non-releasably engage with the second end 14 of another formed laminated cover 15 positioned in top- to-tail relationship with said first formed cover. In a further example, the first edge 8 of a first formed laminate 9 can have an engagement means adapted to releasably or non-releasably engage with a complementary engagement means on the second edge 10 of another laminated cover 11. A similar engagement means can be provided at the first end 12 of a first formed cover 13 that is adapted to engage with a complementary engagement means on the second end 14 of said other cover 15. Further to this, the engagement means can consist of polymeric zip-type components. This allows a plurality of covers to be formed and positioned to cover any sized body of water.

The types of bodies of water of which the laminate cover 1 is applied to, can be natural or artificial bodies of water. In one example, the body of water can be a swimming pool, for example a home pool, a 10m, 25m or a 50m swimming pool. In another embodiment, the body of water can be a dam built on a farming property. The dam may have dimensions up to or greater than 1 ,000,000 square metres. The bodies of water may have symmetrical or non- symmetrical shapes. In some situations, a single cover can be used to cover a body of water. In other situations, more than one cover may be required to cover a particular body of water. In some circumstances, it may be decided to only cover a portion of a body of water.

In a further example, the first edge 8 of a first formed member 9 can have a first edge engagement means adapted to releasably engage with a complementary second edge engagement means on the second edge 10 of another member 11. A similar engagement means can be provided at the first end 14 of a first formed member 15 that is adapted to engage with a complementary engagement means on the second end 12 of another member 13.

Further to this, the first edge and second edge engagement means can consist of polymeric zip-type components. This allows a plurality of covers to be formed preferably at the site of the body of water and then positioned to cover the body of water.

An example of a zip-type first edge engagement means 30 is shown in Figure 4 (a). An engagement means is attached to a first edge of a planar member 20 of the cover 1. The engagement means 30 can be attached to the planar member 20 by adhesive bonding, thermal fusing, flame lamination, ultrasonic welding, extrusion bonding, sewing, riveting, pressure sensitive tapes or heat reactivatable tapes. An example of a first edge engagement means 30 and a complementary second edge engagement means 31 in an engaged configuration is shown in Figure 4 (b).

An example of a zipping device 40 used to engage two engagement means 30, 31 of Figure 4 is shown in Figure 5. Figure 5 (a) shows an entrance end in which two complementary engagement means 30, 31 are inserted in the zipping device 40. Figure 5 (b) shows the exit end of the zipping device 40 from which the first edge engagement means 30 and the complementary second edge engagement means 31 emerge in an engaged configuration. The zipping device 40 is constructed in such a way that the first edge and second edge engagement means 30, 31 are progressively stretched open and drawn closer to each other and in a manner such that when emerging from the zipping device 40, the first edge engagement means 30 and the complementary second edge engagement means 31 engagement means are releasably engaged.

A cross sectional view of the zipping device 40 at various positions is shown in Figure 6.

An example of a first edge engagement means 30 and a complementary second edge engagement means 31 , at various stages throughout progressing through the zipping device 40 is shown in cross-sectional views in Figure 7, corresponding to regions 41 , 42, 43, 44 and 45 along the longitudinal axis of the zipping device 40 in Figure 6.

In Figure 7 (a), the first edge engagement means 30 and the complementary second edge engagement means 31 , are shown when entering the zipping device at region 41. As the first edge engagement means 30 and a complementary second edge engagement means 31 progress to region 42, the first edge engagement means 30 and the complementary second edge engagement means 31 are stretched open and drawn closer together as shown in Figure 7 (b).

Figure 7 (c) shows the first edge engagement means 30 and the complementary second edge engagement means 31 at the region 43 stretched open further apart still, and drawn closer still to each other. Figure 7(d) shown the first edge engagement means 30 and the complementary second edge engagement means 31 corresponding to region 44, stretched open to an extent such that engagement is possible. Figure 7(e) shows the first edge engagement means 30 and the complementary second edge engagement means 31 drawn closer still such that engagement is achieved, and the first edge engagement means 30 and the complementary second edge engagement means 31 means emerging from the zipping device in an engaged state.

The first edge engagement means 30 and the complementary second edge engagement means 31 , can be released by feeding the first edge engagement means 30 and the complementary second edge engagement means 31 , whilst in an engaged state through the zipping device 40 in the opposite direction to as previously described such that the first edge engagement means 30 and the complementary second edge engagement means 31 are stretched open and drawn apart.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (42)

CLAIMS:

1. A laminated cover for reducing the rate of evaporation of a body of water, the cover comprising at least one first layer of material that is relatively heat reflecting and at least one second layer of material that is relatively light absorbing.

2. A laminated cover of claim 1 wherein the cover is adapted to be positioned above the body of water with the relatively heat reflecting first layer facing upwardly.

3. A laminated cover of claim 1 or 2 wherein the cover further includes at least one intermediate layer.

4. A laminated cover of claim 3 wherein the at least one intermediate layer is formed from a layer of relatively light absorbing material.

5. A laminate cover of any one of the preceding claims wherein the at least one first layer is at least substantially white in colour.

6. A laminated cover of claim 5 wherein the first layer has a substantially white coating or is intrinsically formed from a substantially white material.

7. A laminated cover of any one of the preceding claims wherein the at least one second layer includes a plurality of sealed cavities disposed in a plane and extending outwardly from a substantially flat base.

8. A laminated cover of claim 7 wherein each sealed cavity is substantially circular with a substantially flat base.

9 A laminated cover of claim 7 or claim 8 wherein in one dimension, hereinafter "the x-dimension", the sealed cavities are linearly aligned.

10. A laminated cover of claim 9 wherein in another dimension, hereinafter the "y-dimension", the sealed cavities are off-set from its immediate neighbours in the y-dimension.

11. A laminated cover of any one of the preceding claims wherein the at least one second layer is substantially black in colour.

12. A laminated cover of claim 11 wherein the second layer has a substantially black coating or is intrinsically formed from a substantially black material.

13. A laminated cover of claims 3 or 4 wherein the at least one intermediate layer is substantially black in colour.

14. A laminated cover of any one of the preceding claims wherein the laminate has a plurality of holes formed therein that allow escape of gases built up under the laminate through the cover and to allow rain water to pass through the cover.

15. A laminated cover of any one of the preceding claims wherein the laminate cover has at least one outer edge.

16. A laminated cover of claim 15 wherein the laminated cover is rectangular or square in shape and has parallel first and second ends, and parallel first and second side edges.

17. A laminated cover of claim 16 wherein the first side edge of a first formed laminate is adapted to releasably or non-releasably engage with the second edge of another formed laminated cover positioned in side-to-side relationship with said first formed cover.

18. A laminated cover of claims 16 or 17 wherein the first end of a first formed laminate is adapted to releasably or non-releasably engage with the second end of another formed laminated cover positioned in top-to-tail relationship with said first formed cover.

19. A laminated cover of any one of the preceding claims, wherein the cover further includes a weight means that stops the cover from lifting off the body of water.

20. The laminated cover of claim 19, wherein the weight means is a tubular member.

21. The laminated cover of claim 20, wherein the tubular member is filled with water or another liquid or slurry.

22. The laminated cover of claim 20 or claim 21 , wherein the tubular member is above, below or within the laminated cover.

23. The laminated cover of any one of claims 20 to 22, wherein the tubular member is formed integrally with the laminated cover.

24. The laminated cover of any one of claims 20 to 22, wherein the tubular member is formed separately from the cover.

25. A method for forming a laminated cover for reducing the rate of evaporation of a body of water, the method including the steps of:

(i) forming at least one first layer of material that is relatively heat reflecting;

(ii) forming at least one second layer of material that is relatively light absorbing; and

(iii) bringing the at least one first layer and at least one second layer into face-to-face abutment to form a laminate.

26. A method of forming a laminated cover of claim 25 wherein the method further includes a step of forming at least one intermediate layer that is then incorporated into the laminate in step (iii).

27. A component structure of a cover for a body of water, the structure comprising a planar member having a first edge and at least a second edge, the first edge having an engagement means along at least a portion of its length and the second edge having an engagement means along at least a portion of its length, the first edge engagement means being engageable with a complementary second edge engagement means of a first other planar member and the second edge engagement means being engageable with a first edge engagement means of a second other planar member.

28. A component structure of claim 27 wherein the planar member is rectangular or square in shape and has parallel first and second side edges.

29. A component structure of claim 28 wherein the first side edge of a first planar member is adapted to engage with the second edge of another planar member positioned in side-to-side relationship with said first planar member.

30. A component structure of any one of claims 27 to 29 wherein the planar member has parallel first and second ends, with the first end of a first planar member adapted to engage with the second end of still another planar member positioned in top-to-tail relationship with said first planar member.

31. A component structure of claim 29 wherein the first edge of the first planar member has a first edge engagement means adapted to engage with a complementary second edge engagement means of another planar member.

32. A component structure of claim 30 wherein a first end engagement means is provided at the first end of the planar member that is adapted to engage with a complementary second end engagement means on the second end of still another planar member.

33. A component structure of claims 31 or 32 wherein the respective engagement means are releasable engagement means.

34. A component structure of claim 33 wherein the engagement means is selected from the group comprising zipping devices, snap-lock devices, interlocking mechanisms, clips and pins.

35. A component structure of claim 34 wherein the respective engagement means are a polymeric zip-type interengagement means that are attached to the planar members by adhesive bonding, thermal fusing, flame lamination, ultrasonic welding, extrusion bonding, sewing, riveting, pressure sensitive tapes or heat reactivatable tapes.

36. A component structure of claim 35 wherein a zipping device is used to releasably engage the first edge engagement means and the complementary second edge engagement means.

37. A component structure of claim 36 wherein the zipping device is constructed in a manner such that the first edge and second edge engagement means enter the zipping device in an unengaged state and exit the zipping device in an engaged state.

38. A component structure of claim 37 wherein the first edge and second edge engagement means are disengaged by drawing the first edge and second edge engagement means, whilst in an engaged state, through the zipping device in the opposite direction to the direction used to engage the first edge and second edge engagement means.

39. A component structure of any one of claims 27 to 38 wherein each planar member is made from at least one layer of a polymeric film.

40. A component structure of any one of claims 27 to 38 wherein the planar member is made of at least one layer of a polymeric film and at least one layer of an expanded polymeric foam adhered to the at least one polymeric film such that the planar member is buoyant when applied to the surface of a body of water.

41. A component structure of any one of claims 27 to 38 wherein the planar member is a laminate cover as defined in any one of claims 1 to 24.

42. A method of forming a cover for a body of water comprising the steps of: (i) obtaining at least two component structures arranged to be engaged together to form a cover for a body of water;

(ii) determining the dimensions of the body of water; and

(iii) engaging the component structures to form a cover that at least substantially matches the dimensions of the body of water defined in step (ii).