The present invention pertains to floating covers for open water surfaces. In particular, the present invention provides a new floating tile for shielding open water surfaces from evaporation and external elements.
The need to cover over large open water surfaces arises from the necessity to prevent water loss through evaporation and to protect the water body from external elements causing pollution. Current solutions are various forms of floating covers comprised of flexible membranes with various means of providing buoyancy for floatation and restraints for the membrane. There are a number of issues with flexible floating membranes that include formation of surface puddles due to sagging and hence the need for drainage, inadequate long-term resistance to ultraviolet (UV) radiation and limited durability and life, chemical instability and leakage of pollutants from the membranes into the water body, difficulty of deployment and retrieval with high tensile strength requirement of the membrane to resist external loads, and cost. These issues have limited the utility of existing covers to small reservoirs leaving the covering of large open water surface areas impractical.
Therefore, there is a need for a cost effective, durable, UV-resistant, and practical floating cover for large open water surfaces that is not susceptible to sagging and formation of surface puddles and which easily can be deployed and retrieved without the need for high tensile strength materials and restraints.
The present invention provides a solution for the above stated need with a floating tile comprised of a thin layer of protective material such as concrete at the surface, a layer of buoyant material directly below, and a two-compartment container made from non-biodegradable, chemically stable, and durable material such as plastic that provides housing for the protective and buoyant layers plus adequate submergence depth for stability. The covering of large open water surfaces is accomplished by deploying and closely packing together a plurality of freely floating individual tiles having unrestricted freedom of movement.
The preferred geometric shape of the present invention is a square. This is because of symmetry about both horizontal axes, and straight edges that can perfectly align side by side to accomplish full coverage when packed. However, there may be practical justifications to use other shapes such as rectangular, trapezoidal, triangular, and even circular.
The present invention is comprised of a two-compartment, open top and bottom plastic container with a relatively short compartment atop a taller compartment below with a horizontal partition in-between that serves as the floor of the upper compartment and the ceiling of the lower compartment. The upper compartment fits a layer of buoyant material atop its floor to provide the required buoyancy for the tile. The buoyant material can take a number of forms including expanded polystyrene (EPS), air filled cells, honey come membrane, second partition with air gap, etc., or the partition between the upper and lower compartments itself could be made buoyant thus eliminating the need for a separate buoyant layer. With the buoyant layer in place, the upper compartment leaves the exact depth above to house the required thickness of the protective material, which serves as the exposed surface of the tile providing protection against the elements, particularly UV radiation. One efficient way of forming the protective layer is casting by pouring wet concrete in the upper compartment filling the space above the buoyant layer, with surface either flush with the container top, or shaped as desired with a mold or a stamp.
The purpose of the lower compartment is to provide the tile with adequate submerged depth so adjacent tiles can afford large relative vertical movement without one tile piling on top of the other. This is one reason for the lower compartment being relatively tall compared with the upper compartment. There is at least one hole in the wall of the lower compartment just below the ceiling to vent out the trapped air inside when the tile is placed in water. The exhaust of the trapped air is necessary to enable the complete submergence of the lower compartment down to the ceiling and below, such that the buoyant layer in the upper compartment can serve its buoyancy function.
With the tile floating, the lower compartment is completely filled with water. The means that the effective weight of the tile also includes the weight of the water inside the lower compartment, which is several times larger than the combined weight of the materials that make up the tile. Any attempt at moving the tile laterally will also move the water inside the lower compartment and any effort at lifting the tile vertically will also lift the water inside until the hole(s) in the wall of the lower compartment is above the water level to allow entry of air and permit the slow draining of the lower compartment. This is a crucial feature of the present invention that gives the tile much added inertia and stability and provides it with resistance against external forces such as the wind and water currents.
The above-disclosed arrangement and features of the present invention addresses and resolves the major issues and shortcomings of the present art. The present invention provides a truly simple and cost-effective means of covering large areas of open water surfaces with concrete, which is a highly durable and tested material widely used for paving open surfaces with tremendous durability and success.
It is an object of the present invention to provide a cost effective, durable, UV-resistant, and practical floating cover for large open water surfaces that is not susceptible to sagging and formation of surface puddles.
It is an object of the present invention to provide improved elements and arrangements by apparatus for the purposes described thereof, which is comparable in cost with existing systems, dependable, and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
Referring to
The preferred embodiment of tile 100 in Table 1 is comprised of a 0.04-inch thick double-compartment container 101 made from high density polyethylene (HDPE) having a 48-inch by 48-inch square surface area, with upper compartment thickness of 0.75 inches containing 0.5-inch thick expanded polystyrene buoyant layer 102, plus 0.25-inch thick layer of concrete protective layer 103, and lower compartment having 6.0-inch tall walls. Accordingly, the sum total weight of the individual components is 54.4 lbs having a total volume of 1872.0 cubic inches (1.08 ft3). Dividing the total weight of the individual components by the total volume results in a tile unit weight of 50.2 lbs/ft3 i.e. less than 62.4 lbs/ft3, which is the minimum unit weight of water 106 (assuming worst case scenario of no dissolved salts). The corresponding specific gravity of tile 100 is 50.2 lbs/ft3 divided by 62.4 lbs/ft3 i.e. 0.80. Therefore, the preferred embodiment of tile 100 floats in water. Based on Archimedes Principal, the weight of water displaced equals the total weight of the tile, which is 54.4 lbs. It follows that the corresponding volume of water displaced equals the submerged volume of tile 100, which is 54.4 lbs divided by 62.4 lbs/ft3 i.e. 0.87 ft3 (1506.8 cubic inches). Accordingly, the corresponding depth of submergence is 6.59 inches leaving 0.16 inches of tile exposed above the water surface.
If it is desired to increase the height of tile above surface of water 106, then the depth of submergence may be reduced by increasing the thickness of buoyant layer 102. Table 2 shows the impact of lowering partition 105 by 0.5 inches and using a 1.0-inch thick buoyant layer 102 while keeping the thickness of protective layer 103 the same.
The total volume of material comprising tile 100 increases from 1872.0 to 3024 cubic inches (62%) while the weight of the tile increases by just one pound from 54.4 to 55.4 lbs (2%). Consequently, the unit weight of the tile 100 reduces from 50.2 to 31.7 lbs/ft3 (37%). This results in submerged depth of tile 100 to reduce from 6.59 to 6.11 inches leaving 0.64 inches of tile 100 exposed above water surface.
The present invention is susceptible to modifications and variations which may be introduced thereto without departing from the inventive concepts and the object of the invention. Geometric forms, dimensions, and materials, other than those disclosed may be used.
While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is to be understood that the present invention is not to be limited to the disclosed arrangements, but is intended to cover various arrangements which are included within the spirit and scope of the broadest possible interpretation of the appended claims so as to encompass all modifications and equivalent arrangements which are possible.