Patent Application
20140102023
This application relates generally to support of above ground tanks used in the oil and gas industry and other environments and, more particularly, to a system and method that is both lightweight and durable.
In the oil and gas production industry, above ground tanks (e.g., commonly referred to as 400 barrel tanks) are used for storage of material (e.g., oil or water). Separating such tanks from the ground is desired. One standard technique for support of such tanks is placement of a metal ring on the ground, which is filled with gravel, with the tank being placed on the gravel bed. However, the system is labor intensive, time consuming and the components are not readily disposable in a landfill. Moreover, tanks sitting on the gravel bed are subject to corrosion and freezing of stored material in extremely cold weather. Another techniques used in the past involved providing segments of blue board coated with a paint, epoxy or urethane coating (similar to sprayed on a truck bed liner) with ratchet straps used to hold 4-5 blue board segments together to form a tank pad. However, the ratchet straps are subject to degradation, and blue board tends to be a weighty product.
It would be desirable to provide a light weight, durable tank support system that is both easy to transport and easy to manipulate and construct on site.
In one aspect, a method of making a modular pad unit that can be used to produce a circular tank storage pad is provided. The method includes: creating a rigid foam core member having a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part; utilizing a plural component processing system to apply a polymer coating to the rigid foam core member such that the rigid foam core member is encased in the polymer coating produce a modular pad unit; and wherein the resultant modular pad unit has a substantially uniform thickness and perimeter shape with circular part, male key part and female keyway part sized and positioned such that multiple modular pad units can be interconnected in an interlocking manner such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle. The modular pad unit may be sized such that the resulting circles is at least ten feet in diameter (e.g., large enough to hold a large, similar diameter storage tank).
In another aspect, a method of supporting a storage tank in the field involves: utilizing a plurality of modular pad units, each modular pad unit including a rigid foam core having a polymer coating thereon, each modular pad unit having a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part, wherein the male key part is configured for mating with the female keyway part; arranging the modular pad units at a site where the storage tank is to be located, including interlocking the modular pad units such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle, the multiple interlocked modular pad units providing a circular storage pad that is at least ten feet in diameter and that has a thickness of at least three inches; and placing a bottom of the storage tank directly on the circular storage pad, whereby the circular storage pad supports the storage tank and isolates the storage tank from the ground at the site.
In a further aspect, a supported tank system includes a plurality of modular pad units. Each modular pad unit includes a rigid foam core encased in a polymer coating and has a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part. The male key part of each modular pad unit is configured for mating with the female keyway part of another modular pad unit in a manner that inhibits the male key part from being laterally puller away from the female keyway part. The modular pad units are arranged in an interlocking manner such that the male key part of each modular pad unit mates with the female keyway part of another pad unit and the circular parts of the modular pad units align such that the multiple interlocked modular pad units providing a circular storage pad that is at least ten feet in diameter and has a thickness of at least three inches. An upright storage tank unit is supported on the circular storage pad. The storage tank has a diameter that is less than or equal to the diameter of the circular storage pad, and a volume of at least 10,000 gallons.
Referring to
In one implementation the rigid foam core may be an expanded polystyrene material, though variations are possible. Likewise, in one implementation the polymer coating may be applied using a plural component spray process. For example, a bonded monolithic polymer seal (BMPS) material may be used, made up of a plural component system consisting of an “isocyanate” (also known as a diisocyanate with other variations that may include: isophorone diisocyanate, methylene diphenyl diisocyanate, toluene diisocyanate or hexamethylene diisocyanate) and mixed with one or more of the following: an alcohol, an hydroxyl, a polyol, or an amine, creating a polyurethane or polyurea compound. An example of this material is Custom Linings 911 pure polyurea, available from Custom Linings, Inc. of Beuna Vista, Colo., but there are products that may be used. As used herein, the term plural component processing technique means blending two or more chemicals together in a specific or varying ratio with either direct impingement equipment, equipment utilizing a static mixer assembly to mix/bled the chemicals or by mixing in an open container by hand or by other mechanical mixing method to produce material that cures to some degree. An impingement mix spray process may be best suited to the production of the modular pad units described herein. In one implementation, the polymer coating has a tensile strength of at least 1500 (such as at least 2000 psi or about 2500 to 2700 psi according to ASTM D-412 test), an elongation of at least 200% (according to ASTM D-412 test), a tear strength of at least 300 pli (e.g., 400 pli or greater according to ASTM D-412 test) and a hardness of at least D40 (e.g., D50 or greater according to ASTM D-2240 test).
Each modular pad unit includes a perimeter 14 having a shape that is suited to interlocking of multiple pad units. Specifically, the perimeter 14 includes a circular part 16, a male key part 18 and a female keyway part 20. In the illustrated embodiment, the male key part and female keyway part have complimentary wedge shapes, but other shapes are possible. As seen in
Referring to
Thus, a method of supporting a storage tank in the field is provided and involves: utilizing a plurality of modular pad units, each modular pad unit including a rigid foam core having a polymer coating thereon, each modular pad unit having a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part, wherein the male key part is configured for mating with the female keyway part; arranging the modular pad units at a site where the storage tank is to be located, including interlocking the modular pad units such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle, the multiple interlocked modular pad units providing a circular storage pad that is at least ten feet in diameter and that has a thickness of at least three inches; and placing a bottom of the storage tank directly on the circular storage pad, whereby the circular storage pad supports the storage tank and isolates the storage tank from the ground at the site.
As noted above, the polymer coating may be a polyurethane or polyurea compound that is applied using a plural component spray process, and the polymer coating may have a thickness of at least 80 mils (e.g, between about 80 mils and about 125 mils). The circular storage pad may have an R-value of at least 26 for insulating the tank from the underlying surface on which the pad rests.
For the purpose of ease of transport and handling of the modular pad units, each modular pad unit may have a weight of less than 75 pounds (e.g., less than 50 pounds). Such weights can generally be carried and manipulated by a single individual in the field. In one implementation, each modular pad unit may be sized and shaped for stacking and placement upon a pallet 44 per
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible.
