AU6446099A - Modular floating covers for water storages (evaporation prevention cover) - Google Patents

Description

AUSTRALIA

Patents Acts 1990 COMPLETE SPECIFICATION STANDARD PATENT MODULAR FLOATING COVERS FOR WATER STORAGES (evaporation prevention cover) The following statement is a full description of this invention, including the best method of performing it known to me.

MODULAR FLOATING COVER FOR WATER STORAGES (evaporation prevention cover) Field of Invention.

The present invention relates to a modular floating impermeable cover applied to a water surface for the prevention of water loss through evaporation.

Evaporation is prevented by the surface of the water being in full contact with the underside surface of the impermeable cover material thereby preventing circulation of air under the cover and allowing the evaporation process to occur at the water surface cover material interface.

Background Art The use of synthetic impermeable materials is available in the market place for covers to swimming pool and other small enclosed bodies of water.

The purpose of these pool type covers is primarily to keep the pool clear of leaf and other litter which may be blown into the pool. A second purpose is to conserve pool chemicals and retain solar heat energy or the water in the pool.

•."!'"Attempts have been made over the past 30 40 years to produce a floating cover for large water storage such as farm dams to minimise or prevent loss of water through the naturally occurring evaporation process caused by solar energy, temperature difference and wind on the surface of the water. These Attempts may have been technically feasible but were frequently uneconomic to rural users.

This invention brings together a new design which is technically and economically feasible.

Summary of Invention In a first aspect of the present invention provides for the floating cover to be modular in form. The dimension of the module are determined by physical constraints such as size of water storage, access to site, ease of construction, transport and installation considerations. The nominal module dimensions used for further description of the floating modular cover unit is a rectangular 5 metres by 15 metres. The actual module size used to cover a water storage may be larger or smaller than that the nominal size.

In a second aspect of the present invention the shape of the modules may be rectangular, circular, hexagonal, segmental or any other shape to suit the shape of the water storage.

In a third aspect the present invention provides a thin impermeable barrier of synthetic polypropylene fabric material as the barrier to prevent loss of water from the water surface through evaporation. The fabric material constitutes the "cover" of the floating modular cover unit In a fourth aspect the present invention provides a method of fabricating "35 the fabric into large areas of any desired shape and to contain sleeves for support floats contained in the modular cover unit. The sleeves are formed by welding, sewing or other form of fixing the fabric material to itself In a fifth aspect the present invention provides for the use of polystyrene, polypropylene, polyurethane or other light weight material, sealed airtight tube or other floatation device to act as floats and stiffening ribs to the modular cover.

3 In a sixth aspect the present invention provides for the use of straps or ties fixed to the modular cover units and used to secure or fix the modules together to an integral cover over the whole surface of the water storage.

In a seventh aspect the present invention provides for some modular cover units to include a weighted skirt built in or attached to an edge of the cover and which hangs below the cover. The skirt material may be the same material as the cover. The weight is fixed, held and or supported by the skirt. The weight may be any device which will add weight to the skirt and hold it vertically under the cover.

Brief Description of Drawings In order to achieve a better understanding of the nature of the present invention the preferred arrangement of the invention will be described, by way of .9 example only, with reference to the accompanying drawings Example of Invention Figure 1 is shows an isometric view of a modular cover unit, sleeve detail and float detail in which identifies the polypropylene multi-filament fabric material forming the cover, is a edge sleeve formed by folding the edge of the cover sheet cover back on itself and welding the fabric along the join, creating a hollow sleeve for the float, is a mid rib sleeve formed by welding a continuous piece of fabric material to the main cover material is the polystyrene float and stiffening element which is placed in the sleeve by pushing the float up the 4 sleeve, is the strap or tie for linking modules together to form the full or large cover. The strap or tie has hook and loop fasteners sewn onto the backing strap which is made of cover fabric material. The strap is welded on to the cover.

Figure 2 is an isometric view of multiple covers installed on a large water storage or damrn, is the earth wall of the dam with sloping sides. is the full water storage line of the dam, is the multiple modular floating covers linked together by the straps, covering the whole of the water surface.

Figure 2 is a view of an assembled cover on a large water storage.

Modes for Carrying Out the Invention As shown in Figure 2 the invention can have any number of modular units on a single cover. Units can also be arranged to match a particular shape of storage.

30 The extent of a single cover need not extend over the whole of the water surface at full storage level (FSL). A width of clear water may be left between the edge of the cover and the FSL to provide an expanse of water for environmental purposes and allow for fluctuations in water level in the dam.

S. Anchorage of the cover to the bank of the dam may be accomplished by rope 40 attached to the straps or ties and fixed to the bank by weights or anchor stakes .or steel pins.