FIELD OF THE INVENTION
The present invention relates to open top outdoor fluid storage tanks, and more particularly to a buoyant cover that insulates open top outdoor fluid storage tanks to prevent fluid and heat loss.
BACKGROUND AND SUMMARY OF THE INVENTION
Buoyant covers are used to insulate open top outdoor fluid storage tanks to prevent fluid and heat loss. Many floating cover systems have been tried for Oil & Gas operations in order to reduce energy loss from open top outdoor fluid storage tanks that expose water to the environment. In most cases, water used for fracking operations is heated. Heating the water exponentially increases the amount of water and energy loss due to evaporative, conductive, convective, and radiative methods of energy transfer. Placing a floating cover on the surface of the water can reduce evaporative energy loss by 65% to 85% depending on conditions.
Because of the significant problems associated with water and energy loss, many types of floating covers have been tried, but all of them suffer from being disrupted by high winds. High winds can disrupt the floating cover by moving the cover within the tank to expose more of the water's surface, lifting the cover out of the tank entirely, or causing water to accumulate on top of the cover, eventually causing the cover to sink and expose the water's surface. High winds create negative pressure eddies above conventional floating covers that eventually lift the material. Not only is the water surface subsequently exposed, but the insulating material conventional floating covers is made from is vulnerable to wind damage.
Therefore, a need exists for a new and improved buoyant cover that is resistant to being lifted and damaged by high winds. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the buoyant cover according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of providing a buoyant cover that is resistant to being lifted and damaged by high winds.
The present invention provides an improved buoyant cover, and overcomes the above-mentioned disadvantages and drawbacks of the prior art. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide an improved buoyant cover that has all the advantages of the prior art mentioned above.
To attain this, the preferred embodiment of the present invention essentially comprises a planar body, the body having a first buoyant insulating layer, a second tensile layer overlaying the first buoyant insulating layer, the planar body having a periphery configured based on the tank perimeter to provide a limited gap with the tank perimeter, and the body defining a plurality of peripheral holes positioned about the periphery and proximate the periphery. The second tensile layer may be wrapped about an edge of the first buoyant insulating layer. There may be an underlying portion of the second tensile layer near the periphery. A peripheral seam may be sewn through the underlying portion and the first buoyant insulating layer. The peripheral holes may penetrate the underlying portion. There may be grommets defining the peripheral holes. The planar body may have a circular periphery. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top perspective view of the current embodiment of a buoyant cover constructed in accordance with the principles of the present invention in use attached to an open top outdoor fluid storage tank.
FIG. 2 is a side sectional fragmentary view of the buoyant cover of FIG. 1 in use attached to an open top outdoor fluid storage tank with the water at a high level.
FIG. 3 is a side sectional fragmentary view of the buoyant cover of FIG. 1 in use attached to an open top outdoor fluid storage tank with the water at a low level relative to FIG. 2.
FIG. 4 is a top view of one-half of the first buoyant insulating layer of the buoyant cover of FIG. 1.
FIG. 5 is a side sectional fragmentary view of the buoyant cover of FIG. 1 in use with the two halves of the buoyant cover releasably connected to one another.
FIG. 6 is a top isometric view one-half of the buoyant cover of FIG. 1 rolled up on a core to facilitate transportation and storage.
The same reference numerals refer to the same parts throughout the various figures.
DESCRIPTION OF THE CURRENT EMBODIMENT
An embodiment of the buoyant cover of the present invention is shown and generally designated by the reference numeral 10.
FIG. 1 illustrates the improved buoyant cover 10 of the present invention. More particularly, FIG. 1 shows the buoyant cover in use attached to an open top outdoor fluid storage tank 12 having a tank perimeter 14 containing heated water 16. The buoyant cover is a planar body formed in multiple parts (halves 18, 20) in the current embodiment to have a periphery 22 configured based on the tank perimeter to provide a limited gap with the tank perimeter. In the current embodiment, the periphery is circular. The two halves are mirror images of one another and are each semi-circular in shape. Each half has a first buoyant insulating layer 24 and a second tensile layer 26 overlaying the first buoyant insulating layer. Each half defines a plurality of peripheral holes 28 positioned about the periphery and proximate the periphery. A plurality of vertical lines 30 each has an upper end 32 configured to connect to an upper portion of the tank 34 and an intermediate portion 36 passing through a respective one of the peripheral holes. A weight 38, which is a sandbag in the current embodiment, is connected to a lower end 40 of each line to place each line in tension to retain the periphery of the buoyant cover adjacent to the tank perimeter. In the current embodiment, the open top outdoor fluid storage tank has a height of 12 feet and a diameter of 135 feet. However, the buoyant cover can be made in any desired size to fit a corresponding open top outdoor fluid storage tank, which typically have a diameter in the range of 70 feet to 195 feet.
FIGS. 2 & 3 illustrate the improved buoyant cover 10 of the present invention. More particularly, FIG. 2 shows the buoyant cover in an elevated position with the heated water 16 at a high level within the open top outdoor fluid storage tank 12. FIG. 3 shows the buoyant cover in an elevated position with the heated water 16 at a lower level within the open top outdoor fluid storage tank 12 relative to FIG. 2. The plurality of vertical lines 30 received in the peripheral holes 28 allow the buoyant cover to rise and fall in response to changes of the amount of heated water in the open top outdoor fluid storage tank 12. The water level continually changes during the fracking process. The lines being placed in tension by the weights 38 ensures the buoyant cover can only move in a vertical direction with respect to the tank perimeter. This movement limitation prevents the buoyant cover from being displaced by wind, flipped over, or being sunk by water accumulation from windblown exposed water. The second tensile layer 26 also increases the wind resistance of the buoyant cover by reducing the negative pressure that wind would otherwise create on the first buoyant insulating layer 24. In the current embodiment, the second tensile layer is a woven mesh of material manufactured by Wind Defender, LLC of Pottsville, Pa. The second tensile layer is a geotextile windscreen made of knitted, green, UV stabilized high density polyethylene (HDPE) filament. Use of the second tensile layer material to reduce negative pressure buildup and subsequent wind damage to a high-density polyethylene liner customarily used in landfills has been proven. Testing of the buoyant cover on site in a remote area of Colorado established the buoyant cover maintained its desired position covering the heated water despite being subjected to wind speeds exceeding 60 mph.
FIG. 4 illustrates the improved first buoyant insulating layer 24 of the present invention. More particularly, FIG. 4 shows how each half 18, 20 of the first buoyant insulating layer of the buoyant cover 10 is formed from a plurality of strips of material 40. The first buoyant insulating layer is a ⅛-inch-thick foam sheet 42 made of polyethylene foam manufactured by ProtecPac of Sidney, Ohio that has been laminated on both sides with woven coated polyethylene upper and lower sheets 44, 46 manufactured by Intertape Polymer Group, Inc. of Sarasota, Fla. The upper and lower sheets are HDPE tapes that are then coated with a 1.5 mil blue upper layer and a 1.5 mil white lower layer. The total thickness of the polyethylene upper and lower sheets is around 3-4 mil on each side of the foam. The foam is a closed cell-foam sheet to not take on any water during usage. The strips of material are acquired having a 6-foot width. Each strip of material is welded to adjacent strips of material with a heated wedge welder. Once the strips of material are welded together, the periphery is trimmed in a semicircular shape to fit the tank perimeter 14 so that the first buoyant insulating layer will fit within the open top outdoor fluid storage tank and float freely while covering the surface of the heated water 16. Depending on customer request, about 95-99% of the surface of the heated water is covered by the two halves of the first buoyant insulating layer.
FIG. 5 illustrates the improved buoyant cover 10 of the present invention. More particularly, FIG. 5 shows the two halves 18, 20 of the buoyant cover connected by fasteners 48, which are carabiners in the current embodiment. The second tensile layer 26 is manufactured in 20-foot-wide sheets that are sewn together to match the shape of each half of the first buoyant insulating layer 24 while being slightly larger. The increased size of the second tensile layer 26 of each half of the buoyant cover relative to each half of the first buoyant insulating layer enables the second tensile layer to be wrapped about an edge 50 of the first buoyant insulating layer 24 to encapsulate the entire top surface 52 of the first buoyant insulating layer. The wrapping results in an underlying portion 54 of the second tensile layer near the periphery 22 that extends 6-inch underneath in the current embodiment. A peripheral seam 56 is sewn through the underlying portion and the first buoyant insulating layer to secure the second tensile layer to the first buoyant insulating layer. The peripheral holes 28 penetrate the underlying portion and are defined by #2-#3 grommets 58 in the current embodiment to prevent tearing. The two halves of the buoyant cover are joined at a seam 60 with peripheral holes aligned with respective peripheral holes in an adjacent half, and the fasteners connected to each peripheral hole of a corresponding pair of peripheral holes. In the current embodiment, the peripheral holes are spaced every 4 feet along the seam and every 6 feet along the semicircular-shaped portion of the periphery.
FIG. 6 illustrates the improved buoyant cover 10 of the present invention. More particularly, FIG. 6 shows how each of the two halves 18, 20 of the buoyant cover can be rolled up on a core 62 to facilitate transport and storage. To use the buoyant cover, the two halves are unrolled and then unfolded. Subsequently, the two halves are connected together at the seam 60 with the fasteners 48, and the vertical lines 30 with connected weights 38 are passed through the peripheral holes 28. The open top outdoor fluid storage tank 12 is then constructed around the buoyant cover, and the upper ends 32 of the lines are connected to the upper portion of the tank 34. Finally, the tank is filled with heated water 16 underneath the buoyant cover, and the buoyant cover rises up the lines with the water level while covering the heated water.
While a current embodiment of a buoyant cover has been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
Patent Application
20210229901
