Abstract:
A fluid storage vessel can include an expanded polystyrene (EPS) core formed into an integrated unit so that it can reliably withstand the hydrostatic pressures of large volumes of water (or other liquids). The EPS core can be wrapped with a high tensile strength material to accommodate performance under full volume loads. The vessel can be coated on the exterior and/or interior with a fiber reinforced cementitious composite. A vessel can optionally include thermostatically controlled heaters for use in cold environments.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/582,808, entitled “Thermally Insulated Fluid Storage Vessels and Methods of Making the Same,” and filed on Jan. 3, 2012, which is incorporated herein by reference in its entirety. 
     
    
       [0002]    Embodiments relate generally to fluid or liquid storage tanks or vessels, and, more particularly to thermally insulated fluid storage vessels and methods of making the same. 
         [0003]    Water shortages are a growing problem in many locations in the U.S. and throughout the world. Capturing rainwater can usefully harvest what may otherwise be lost as “storm water”. Rainwater may be an underutilized economic resource that can be harvested to help alleviate water shortages and to help meet growing potable and non-potable water demand. The U.S. water infrastructure is aging, thus providing opportunities for investment in decentralized, and therefore potentially more secure, water supply solutions. Rainwater harvesting can be an area of economic growth that may create jobs. 
         [0004]    Typically, the drier the region, the more valuable captured rainwater may become. For example, in locations where annual rainfall averages 12 inches, the average home could harvest over 15,000 gallons of water annually, which could be used to help reduce demand on limited water supplies. A common challenge of harvesting rainwater in arid and semiarid regions is that rain events may occur infrequently and may drop substantial quantities of water in a relative brief period of time thereby producing excessive storm water runoff and flooding. Much of the rainwater may be lost to offsite drainage. 
         [0005]    In locations having similar rainfall levels, a 100,000-square-foot building could harvest 720,000 thousand gallons of water annually, which could help reduce storm water runoff, flooding and demand on water supplies. 
         [0006]    Rainwater is naturally ozonated and may also contain superior nutrients for all living organisms, which, with minimal onsite treatment, may exceed drinking water standards established by the Environmental Protection Agency (EPA). 
         [0007]    Both major plumbing code bodies within the U.S. have newly minted codes and standards to support widespread adoption of rainwater harvesting. 
         [0008]    Conventional fluid (or liquid) storage vessels (or tanks) can be heavy, costly to transport and costly to install. Moreover, conventional tanks may not be readily installed into areas having existing structures built in relatively close proximity. 
         [0009]    Conventional storage tanks may fall into one of two broad categories of design, above ground and below ground. 
         [0010]    Above ground tanks can be simple “industrial solutions” that may suffer from one or more problems, such as: a need to be manufactured remotely and transported from a manufacturing location to an end user location via intermediate distributors; above ground tanks may not be customized for an end user&#39;s site and may not even be allowed in locations with aesthetic design guidelines (e.g., covenanted subdivisions, or the like); and above ground tanks may not be insulated. An uninsulated storage vessel, such as an above ground tank, may be subject to failure resulting from ambient temperatures at or below freezing. 
         [0011]    Below ground tanks may be more complex and more expensive than above ground tanks. Below ground tanks may suffer from one or more of the following problems or limitations: a need to be manufactured remotely and transported from a manufacturing location to an end user&#39;s location via intermediate distributors; and below ground tanks may involve excavating a hole larger than the tank, which can be inherently disruptive to a site, and can often be a potentially dangerous operation involving conformance with OSHA regulations. Further, displaced soil might not remain at the tank burial site and may need to be transported away. 
         [0012]    Also, below ground tanks may present a permanent buried hazard that may require the area over the buried tank be fenced to restrain persons and vehicles from walking or driving vehicles over a below ground tank. 
         [0013]    Embodiments were conceived in light of the above-mentioned limitations and problems, among other things. 
         [0014]    An embodiment can include custom fabrication of insulated scalable collection and storage vessels for fluids which can be located in many exterior ambient temperature contexts and for which physical access and/or aesthetics may factor into construction and permitting requirements. An embodiment can also include a field-constructed vessel that can be built and used within a plurality of existing (or planned) stationary structures such as homes and commercial or institutional buildings. 
         [0015]    Further, an embodiment can be adapted for use on mobile structures and/or in agricultural enterprises (e.g., for applications such as ocean going vessels, house boats, fish farming, livestock watering, crop irrigation, or the like). 
         [0016]    An embodiment can also be adapted to store water or other fluids. Various fluids can be stored in vessels with modifications as may be required by regulatory agencies (e.g., fossil fuels, biodiesel fuels, home heating fuels, industrial chemicals, food ingredients, or the like). With minor user-initiated modifications, an embodiment can also be used to store materials which can be bulk transported with hoses and which need to be kept dry (e.g., sugars, grains, animal feeds, powdered chemical or food compounds, or the like). 
         [0017]    In general, an embodiment can include an above-ground monolithic thermally insulated fluid collection and storage vessel suitable for storing various fluids, such as, for example, rain water. 
         [0018]    An embodiment can also provide a method of fabricating a customized vessel of scalable size (e.g., from about 1,000 gallon capacity to about 25,000 gallon capacity, or more) including surface construction material options which will allow for customized external design amenities supporting the purposes of receiving and storing fluid at a range of ambient temperatures (e.g., within about 17 degrees Celsius to about 50 degrees Celsius). The construction method embodiments described herein can be used for settings in which construction access is limited and/or external appearance constraints apply. 
         [0019]    It will be appreciated that the embodiments described herein are for illustration purposes and may represent minimal requirements for the use of representative materials, assembly of said materials, and resulting performance of these assembled materials. 
         [0020]    One or more embodiments can include covering a modular expanded polystyrene (EPS) perimeter core (or similar material) on the interior with a field applied fluid-proof interior shell and, on the exterior, with a field applied high tensile strength outer shell. The assembly may be subsequently coated with any of a number of outer covering materials amenable to a broad range of augmented visual design features. 
         [0021]    One or more embodiments can include a scalable customized design and on-site fabrication process for fluid collection and storage vessels suitable for exterior locations that are above ground. 
         [0022]    At least one embodiment can include partially recessing a vessel into the ambient ground, which can reduce exterior site disturbance and long term on-site potential buried hazards and liabilities. This feature can also minimize or eliminate a need for powered excavation equipment to excavate, place and/or assemble a vessel, which can reduce total installation cost. 
         [0023]    An embodiment can also permit fluid collection and storage in a range of ambient weather temperature conditions (e.g., from about −17 degrees Celsius to about 50 degrees Celsius) due to a feature of selectable insulation performance for a contemplated embodiment. 
         [0024]    One or more embodiments can include a foam insulation core having an interior composite layer for hosting a fluid-proof membrane and an exterior high tensile strength polymer-embedded layer. A plurality of external coatings and architectural finishes may be applied to the exterior layer. 
         [0025]    One or more embodiments can be constructed for placement and operation within the interior of various types of buildings for which a fluid storage and/or collection vessel may be desired. 
         [0026]    An embodiment can contain a desired fluid volume. The various components for assembly can be affixed together using any of a range of polymeric bonding agents. In an embodiment having a horizontal base and top cover, the horizontal base and top cover can be fitted over the vertical cylindrical perimeter wall to complete the fluid vessel&#39;s encapsulation function. 
         [0027]    An embodiment can include a process of field assembly of a vessel comprising three primary materials: 
         [0000]    (1) EPS (Expanded Polystyrene or similar insulating polymeric material) including:
 
a) a horizontal round or elliptical base,
 
b) a vertical cylindrical perimeter wall consisting of a plurality of panels precut to conform to a specified arc and height, assembled into a circular, elliptical, or other curvilinear geometry, and with upper and lower edges formed to interface with
 
c) a horizontal round or elliptical top cover.
 
(2) an inner surface coating of glass-fiber reinforced, polymer modified, cementitious composite adhered to interior surfaces of the EPS pieces of the assembled vessel to protect said vessel from damage (by pressure or heat) and for hosting a liquid proof or liquid resistant coating or membrane between the EPS assembly and the stored fluid.
 
(3) An outer wrap comprising an air curing-liquid polymer-embedded high tensile strength fiber reinforced polymeric wrap which can adhere to exterior surfaces of the EPS assembly, and which upon curing to a solid state, is capable of hosting a secondary layer of fiber reinforced, polymer modified, cementitious composite that can be adhered to the vessel&#39;s high tensile strength fiber reinforced polymeric wrap, and which can host various architectural features.
 
         [0028]    In yet another embodiment, a vessel can be constructed and disposed on leveled natural ground in exterior locations and/or on leveled building interior locations also. The exterior of the base, side, and top cover of the vessel assembly can include variable assemblies of the above listed primary materials according to the thermal engineering and structural engineering requirements of a contemplated embodiment. 
         [0029]    An embodiment can provide customized scalable insulated monolithic fluid collection and storage solutions with an ability to accommodate various selectable thermal insulation values, and to host many various exterior architectural shapes and finishes. Further, an embodiment can be installed in previously inaccessible exterior and interior locations and provide a vessel having an assembly process that can be carried out by individuals skilled in the art of construction and general contracting such that the vessel can be constructed and installed in places which were previously inaccessible or disallowed and can accommodate larger fluid volumes than may be currently available with pre-manufactured vessels. 
         [0030]    The top cover of the vessel assembly may host an architecturally preferred weather-proof finish as fabricated by the installer. The cover can include an opening into which a fluid, such as rain water, can be admitted into the vessel. Further, optional parts to the vessel assembly may include, a grate across the opening in the top of the vessel assembly, an interior ladder, a through-wall fluid overflow drain near the top of the vessel assembly, a fluid discharge valve assembly near the bottom the vessel, an aeration pump or heating element to mitigate freezing within the vessel assembly, one or more fluid inlets and/or outlets, internal and external piping, valves, regulators and sensors. Installation instructions can include recommendations for how a plurality of architectural shapes for encapsulating the vessel may host many decorative architectural coatings. 
         [0031]    Some implementations can include a fluid storage vessel having a top portion, a generally cylindrical body portion, and a bottom portion. The body portion can include a built-up construction having a core, a wrap covering an exterior of the core, and a composite material covering an interior of the core. 
         [0032]    The built-up construction can also include another composite material applied to an exterior of the wrap. The top portion, the core of the body portion and the bottom portion can be formed of expanded polystyrene foam. The composite material can include a glass fiber reinforced, polymer modified, and cementitious composite. 
         [0033]    The wrap can include an air curing, liquid polymer embedded wrap. The top portion can include an opening configured to receive a liquid. 
         [0034]    Some implementations can include a method of making a fluid storage vessel. The method can include providing a core member and applying a wrap to an exterior of the core member. The method can also include applying a composite coating to an interior of the core member, and applying a liquid barrier to the composite coating. 
         [0035]    The method can further include applying a different composite material to an exterior of the wrap. The method can also include attaching a top portion and a bottom portion to the core member. 
         [0036]    The composite material can include a glass fiber reinforced, polymer modified, and cementitious composite. The wrap can include an air curing, liquid polymer embedded wrap. 
         [0037]    The top portion can include an opening configured to receive a liquid. 
         [0038]    Some implementations can include a fluid storage vessel prepared by a process. The process can include providing a core member including a bottom portion and at least one body portion and applying a wrap to an exterior of the core member. The process can also include applying a composite coating to an interior of the core member, and applying a liquid barrier to the composite coating. 
         [0039]    The process can further include applying a different composite material to an exterior of the wrap. The process can also include attaching a top portion to the core member. The composite material can include a glass fiber reinforced, polymer modified, and cementitious composite. The wrap can include an air curing, liquid polymer embedded wrap. The top portion can include an opening configured to receive a liquid. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0040]      FIG. 1  is a perspective view of an exemplary thermally insulated fluid collection and storage vessel in accordance with at least one embodiment. 
           [0041]      FIG. 2  is a top cover plan view of an exemplary thermally insulated fluid collection and storage vessel with a hole for admitting gravity-driven fluid into the vessel in accordance with at least one embodiment. The hole may comprise a variety of diameters and shapes such as an ellipse. 
           [0042]      FIG. 3  is an exploded perspective view of an exemplary EPS assembly in accordance with at least one embodiment. 
           [0043]      FIG. 4  is a perspective view of a vessel in accordance with at least one embodiment. 
           [0044]      FIG. 5  is a chart of an exemplary method for making an insulated fluid vessel in accordance with at least one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0045]    An important consideration within one or more embodiments of the present invention relates to securing a core made from an insulating, relatively light material (e.g., EPS foam) into an integrated unit so that it can reliably withstand the hydrostatic pressures of large volumes of water (or other fluids). EPS foam may be sourced from one of the numerous EPS manufacturers throughout the United Sates, such as Insulfoam (a Carlisle Company), for example. The density of the EPS is preferably a minimum of 1.5 pounds per cubic foot, but other densities may be used depending on the requirements of a contemplated design. Higher densities may be required subject to the commonly accepted Strength of Materials “Barlow&#39;s Formula,” an equation which establishes the relationship between internal pressure, allowable stress, nominal thickness and diameter of a pipe. The formula is: P=(2*S*t)/D, where: P=internal pressure, expressed in psig; S=unit stress, expressed in psi; t=nominal wall thickness, expressed in inches; D=outside diameter of pipe, expressed in inches. 
         [0046]    Embodiments can include wrapping an EPS core with high tensile strength materials so as to assure performance under full volume loads. 
         [0047]    The selection of a high tensile strength fiber reinforced polymeric wrap can also be guided by “Barlow&#39;s Formula.” Suitable wraps may be commercially available, for example, the Aquawrap system sold by the Field Applied Composite Systems Group of Air Logistics Corporation (Azusa, Calif.). Aquawrap is a woven glass (bi-axial or uni-axial) fabric which is factory-impregnated with a urethane resin system. 
         [0048]    Fiber reinforced, polymer modified, cementitious composite materials are available from many commercial sources. For example, the cementitious composite materials can include a water-based mix. The sand can be a processed homogenous washed product, such as 20 Grit Silica Sand. The cement can be a common Type I Portland cement. The glass-fiber reinforcement can be an A-R (alkali-resistant) chopped fiberglass fiber commercially available from NEG (Nippon Electric Glass) or Owens Corning. The polymer can be a water-based acrylic thermoplastic co-polymer emulsion. For example Forton VF-774 is a commercially available from Ball Consulting, Ltd. (Ambridge, Pa.). A superplasticizer (e.g., polycarboxylate) can also be used in the composite. 
         [0049]      FIG. 1  shows a cross sectional view of an exemplary embodiment of a thermally insulated fluid collection and storage vessel  10 . The insulated fluid collection and storage vessel  10  includes an outermost fiber reinforced, polymer modified, cementitious composite layer  12 , a polymer-embedded membrane of high tensile strength fiber reinforced polymeric wrap  14 , an EPS core  16 , inner surface coating of fiber reinforced, polymer modified, cementitious composite  18  and a fluid-containing coating or membrane  20 . 
         [0050]      FIG. 2  shows a top view of a lid assembly  22  having a first portion  24  and a second portion  26 . The lid assembly  22  also includes an optional opening  28 . 
         [0051]      FIG. 3  shows a side cutaway and exploded view of an exemplary fluid storage vessel  30 . The vessel  30  includes a top portion  32 , a first body portion  34 , a second body portion  36  and a bottom portion  38 . It will be appreciated that although two body portions are shown for illustration purposes, an actual embodiment can have more or less body portions. 
         [0052]      FIG. 4  shows a cut away perspective view of an exemplary vessel  40 . The vessel includes a generally round top portion  22  with a first top portion  24 , a second top portion  26  and an optional top opening  28 . 
         [0053]    The vessel also includes a generally cylindrical first body portion  34  and a second body portion  36 , and a generally round bottom portion  38 . 
         [0054]    The vessel  40  includes an outermost fiber reinforced, polymer modified, cementitious composite layer  12 , a polymer-embedded membrane of high tensile strength fiber reinforced polymeric wrap  14 , an EPS core  16 , an inner surface coating of fiber reinforced, polymer modified, cementitious composite  18  and a fluid-containing coating or membrane  20 . 
         [0055]      FIG. 5  shows a chart of an exemplary method (or process) for making an insulated fluid containment vessel. The process begins at  502  and continues to  504 . 
         [0056]    At  504 , components for a base member are provided. A base member (e.g.,  38  in  FIG. 3 ) can be made up of one or more components. The process continues to  506 . 
         [0057]    At  506 , the base member is assembled from the components. The components can be held together with an adhesive suitable for use on the material the components are made of. The process continues to  508 . 
         [0058]    At  508 , a polymeric high tensile strength composite (e.g., Aquawrap or the like) is applied to the base member and allowed to cure ( 510 ). 
         [0059]    At  512 , the base member is placed into position for vessel assembly. This can include, for example, placing the base member wholly or partially below ground in a hole dug to suitable dimensions depending on a contemplated design. The process continues to  514 . 
         [0060]    At  514 , vessel body components are provided. For example, the body components can be one or more components used to build one or more generally cylindrical body sections. The process continues to  516 . 
         [0061]    At  516 , the body components are assembled into one or more body members. The body components can be held together with an adhesive suitable for use on the material the body components are made of. The process continues to  518 . 
         [0062]    At  518 , assembled body members are placed on the base. The process continues to  520 . 
         [0063]    At  520 , at least one layer of high tensile strength wrap (e.g., Aquawrap or the like) is applied to the body members. In the case of more than one layer of wrap, subsequent layers can be positioned so as to cover the seams of an underlying layer. The process continues to  522 . 
         [0064]    At  522 , the high tensile strength wrap is allowed to cure. The process continues to  524 . 
         [0065]    At  524 , at least one layer of a fiber reinforced cementitious composite is applied to the exterior of the vessel. The process continues to  526 . 
         [0066]    At  526 , at least one layer of a fiber reinforced cementitious composite is applied to the interior of the vessel. The process continues to  528 . 
         [0067]    At  528 , the fiber reinforced composite is allowed to cure according to manufacturer&#39;s directions or industry standards. The process continues to  530 . 
         [0068]    At  530 , a liquid proof membrane is applied to the interior of the vessel over top of the fiber reinforced composite. The particular type of membrane can be selected based on the type of liquid or fluid the vessel is being built to contain. The process continues to  532 . 
         [0069]    At  532 , an overflow spigot and a discharge valve are optionally installed at appropriate locations in the vessel based on a particular design. The process continues to  534 . 
         [0070]    At  534 , a top member is installed on the vessel. The top member can be permanently affixed or removably mounted to the vessel. The top member can be made using the same core, wrap and cementitious composite build up process as described above regarding the base and body of the vessel. Also, the top can have other features optionally installed such as an access hole to permit liquid to enter the vessel. The access hole can also be sized to permit a person and/or a machine to enter the vessel for cleaning. The access hole can also optionally be covered with a grate to prevent unauthorized access to the vessel and to prevent foreign objects from entering the vessel. The process continues to  536 , where the process ends. 
         [0071]    It will be appreciated that the above steps can be repeated in whole or in part in order to accomplish a contemplated construction of a vessel. 
         [0072]    It is, therefore, apparent that there is provided, in accordance with the various embodiments disclosed herein, thermally insulated fluid collection and storage vessels and methods of making the same. 
         [0073]    While the invention has been described in conjunction with a number of embodiments, it is evident that many alternatives, modifications and variations would be or are apparent to those of ordinary skill in the applicable arts. Accordingly, Applicant intends to embrace all such alternatives, modifications, equivalents and variations that are within the spirit and scope of the invention.