Abstract:
A large volume natural gas storage tank comprises a plurality of rigid tubular walls each having opposing ends and an intermediate segment with a closed tubular cross-section, the plurality of rigid tubular walls arranged in a closely spaced relationship and interconnected at their ends to form a six-sided storage tank, with each of the six sides of the storage tank defined by four successive of the plurality of rigid tubular walls connected end-to-end, such that the interiors of the plurality of rigid tubular walls define an interior fluid storage chamber; and an exterior support structure, the exterior support structure including one or more braces connected to the exteriors of at least some of the plurality of rigid tubular walls and adapted to reinforce the at least some of the plurality of rigid tubular walls against dynamic loading from fluid in the interior fluid storage chamber.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This continuation application claims priority benefit to United States utility patent application Ser. No. 13/681,764 filed Nov. 20, 2012, which claims priority benefit to U.S. provisional patent application Ser. No. 61/562,213 filed Nov. 21, 2011, and which is a continuation-in-part application claiming priority benefit to United States utility patent application Ser. No. 12/823,719 filed Jun. 25, 2010, which is a continuation-in-part application claiming priority benefit to U.S. utility patent application Ser. No. 11/923,787 filed Oct. 25, 2007, which claims priority benefit to U.S. provisional patent application Ser. No. 60/854,593 filed on Oct. 26, 2006, all of which are incorporated herein by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The embodiments disclosed herein generally pertain to storage tanks and more particularly to storage tanks for fluids including liquids and gases. 
       BACKGROUND 
       [0003]    Industrial storage tanks used to contain fluids such as liquids or compressed gases are common and are vital to industry. Storage tanks may be used to temporarily or permanently store fluids at an on-site location, or may be used to transport fluids over land or sea. Numerous inventions pertaining to the structural configurations of fluid storage tanks have been made over the years. One example of a non-conventional fluid storage tank having a cube-shaped configuration is found in U.S. Pat. No. 3,944,106 to Thomas Lamb, the entire contents of which is incorporated herein by reference. 
         [0004]    There has been a progressive demand for the efficient storage and long distance transportation of fluids such as liquid natural gas (LNG), particularly overseas by large ocean-going tankers or carriers. In an effort to transport fluid such as LNG more economically, the holding or storage capacity of such LNG carriers has increased significantly from about 26,000 cubic meters in 1965 to over 200,000 cubic meters in 2005. Naturally, the length, beam and draft of these super carriers have also increased to accommodate the larger cargo capacity. The ability to further increase the size of these super carriers, however, has practical limits. 
         [0005]    Difficulties have been experienced in the storage and transportation of fluids, particularly in a liquid form, by ocean carriers. A trend for large LNG carriers has been to use large side-to-side membrane-type tanks and insulation box supported-type tanks. As the volume of the tank transporting the fluid increases, the hydrostatic and dynamic loads on the tank containment walls increase significantly. These membrane and insulation types of tanks suffer from the disadvantage of managing the “sloshing” movement of the liquid in the tank due to the natural movement of the carrier through the sea. As a result, the effective holding capacity of these types of tanks has been limited to either over 80% full or less than 10% full to avoid damage to the tank lining and insulation. The disadvantages and limitations of these tanks are expected to increase as the size of carriers increase. 
         [0006]    The prior U.S. Pat. No. 3,944,106 tank was evaluated for containment of LNG in large capacities, for example, in large LNG ocean carriers against a similarly sized geometric cube tank. It was determined that the &#39;106 tank was more rigid using one third the wall thickness of the geometric cube. The &#39;106 tank further significantly reduced the velocity of the fluid, reduced the energy transmitted to the tank and reduced the forces transmitted by the fluid to the tank, resulting in substantially less deformation of the tank compared to the geometric cubic tank. 
         [0007]    It was further determined, however, that the &#39;106 configured tank could be improved. 
         [0008]    Additional cubic-shaped tank designs have been developed for LNG and compressed natural gas (CNG). Details of these tanks can be found in US Patent Application Publication Nos. 2008/0099489 and 2010/0258571 assigned to the assignee of the present invention, the entire contents of both publications are incorporated herein by reference. 
         [0009]    Therefore, it would be advantageous to design and fabricate storage tanks for the efficient storage and transportation of large quantities of fluids such as LNG across land or sea. It is further desirable to provide a storage tank that is capable of being fabricated in ship yards for large LNG Carriers. It is further advantageous to provide a modular-type tank design which facilitates design, fabrication and use in the field. 
       SUMMARY 
       [0010]    Disclosed herein are embodiments of a large volume natural gas storage tank. In one aspect, a large volume natural gas storage tank comprises a plurality of rigid tubular walls each having opposing ends and an intermediate segment with a closed tubular cross-section, the plurality of rigid tubular walls arranged in a closely spaced relationship and interconnected at their ends to form a six-sided storage tank, with each of the six sides of the storage tank defined by four successive of the plurality of rigid tubular walls connected end-to-end, such that the interiors of the plurality of rigid tubular walls define an interior fluid storage chamber; and an exterior support structure, the exterior support structure including one or more braces connected to the exteriors of at least some of the plurality of rigid tubular walls and adapted to reinforce the at least some of the plurality of rigid tubular walls against dynamic loading from fluid in the interior fluid storage chamber. 
         [0011]    In another aspect, a large volume natural gas storage tank comprises a plurality of rigid tubular walls each having opposing ends and an intermediate segment with a closed tubular cross-section, the plurality of rigid tubular walls arranged in a closely spaced relationship and interconnected at their ends, with each end of a given of the plurality of rigid tubular walls connected with respective ends of two others of the plurality of rigid tubular walls, such that the interiors of the plurality of rigid tubular walls define an interior fluid storage chamber; and an exterior support structure, the exterior support structure including one or more braces connected to the exteriors of at least some of the plurality of rigid tubular walls and adapted to reinforce the at least some of the plurality of rigid tubular walls against dynamic loading from fluid in the interior fluid storage chamber. 
         [0012]    In yet another aspect, a large volume natural gas storage tank comprises a plurality of rigid tubular walls each having opposing ends and an intermediate segment with a closed tubular cross-section, the plurality of rigid tubular walls arranged in a closely spaced relationship and interconnected at their ends, with each end of a given of the plurality of rigid tubular walls connected with respective ends of two others of the plurality of rigid tubular walls, such that the interiors of the plurality of rigid tubular walls define an interior fluid storage chamber; and a bulkhead positioned in the interior fluid storage chamber across the intermediate segment of one of the plurality of rigid tubular walls, the bulkhead defining at least one aperture to permit restricted fluid communication within the interior fluid storage chamber through the bulkhead. 
         [0013]    These and other aspects will be described in additional detail below. Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0015]      FIG. 1  is a perspective view of a first example of a storage tank containment system having a storage tank and a storage tank support structure; 
           [0016]      FIG. 2  is a perspective view of the bottom side of the storage tank containment system of  FIG. 1  as viewed from the direction of A in  FIG. 1 ; 
           [0017]      FIGS. 3A-3C  are a perspective views of the storage tank system containment of  FIG. 1  showing possible variations in the configuration of the support structure; 
           [0018]      FIG. 4  is a rear partial perspective view of an example of a corner portion of the storage tank as viewed from an interior space of the storage tank; 
           [0019]      FIG. 5A  is a rear partial perspective view of the example corner portion of  FIG. 4  as viewed from an interior space of the storage tank; 
           [0020]      FIGS. 5B and 5C  are rear partial perspective views of alternate examples of corner portions as viewed from an interior space of the storage tank; 
           [0021]      FIGS. 6A and 6B  are section views taken along the line  6 A- 6 A in  FIG. 5A  and line  6 B- 6 B in  FIG. 5B , respectively, showing example methods for completing a joint between constituent parts of the corner portions; 
           [0022]      FIG. 7  is a perspective view of the storage tank containment of  FIG. 1  with the storage tank in phantom to show examples of bulkheads positioned in the horizontal cylinder walls of the storage tank and gusset plates within the interior space of the storage tank; 
           [0023]      FIG. 8  is a perspective view of the storage tank containment of  FIG. 1  similar to  FIG. 7  without showing the storage tank and bulkheads; 
           [0024]      FIG. 9  is a cut-away perspective view of the storage tank of  FIG. 1  taken along the line  9 - 9  showing an interior space formed between the cylinder walls; 
           [0025]      FIGS. 10A-10C  are perspective views of examples of closure plates shown throughout the Figures for closing off the interior space shown in  FIG. 9 ; 
           [0026]      FIG. 11  is a perspective view of a second example of a storage tank containment system having the storage tank and an alternate storage tank support structure; 
           [0027]      FIG. 12  is a perspective view of the bottom side of the storage tank containment system of  FIG. 11  as viewed from the direction of B in  FIG. 11 ; 
           [0028]      FIG. 13  is a cut-away perspective view of the storage tank system in  FIG. 5  showing alternate examples of bulkheads positioned in the horizontal cylinder walls of the storage tank; 
           [0029]      FIG. 14  is an alternate cut-away perspective view of the storage tank containment system in  FIG. 11  showing the bulkheads positioned in the horizontal cylinder walls of the storage tank; 
           [0030]      FIG. 15  is a cut-away perspective view of the storage tank containment system in  FIG. 11  showing an example of corner reinforcements positioned in the bottom corners of the storage tank; 
           [0031]      FIG. 16  is an alternate cut-away perspective view of the storage tank containment system in  FIG. 11  showing an example of corner reinforcements positioned in the bottom corners of the storage tank; 
           [0032]      FIG. 17  is an alternate cut-away perspective view of the storage tank containment system in  FIG. 11 ; 
           [0033]      FIG. 18  is an alternate partially cut-away perspective view of the storage tank system in  FIG. 11  showing further examples of gusset plates within the interior space of the storage tank; and 
           [0034]      FIG. 19  is an alternate partially cut-away perspective view of the storage tank containment system in  FIG. 11  showing alternate examples of corner reinforcements and gussets plates. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    Examples of storage tank containment systems  10  are shown in  FIGS. 1-19 . A first example of a storage tank containment system  10  is shown in  FIGS. 1-10 . Referring to  FIGS. 1-3 , the first example of a storage tank containment system  10  includes a storage tank  12  having a generally cubic configuration, with six geometric square sides oriented at substantially right angles with respect to one another. The tank  12  is preferably constructed from twelve interconnected hollow or tubular walls  14  (a single exemplary wall  14  is indicated in  FIG. 1 ). In the preferred example, the walls  14  are cylindrical-shaped and have a closed, substantially circular cross-section. 
         [0036]    The exemplary storage tank  12  includes four vertically oriented cylindrical, tubular walls  16  positioned approximately 90 degrees apart from one another and eight horizontally oriented cylindrical walls  18  disposed between, and rigidly connecting to, the ends of the vertical walls  16  at corner portions  20   a . As shown, the eight horizontal cylinder walls  18  include four lower cylinder walls  18   a  arranged at a bottom of the storage tank  12  and four upper cylinder walls  18   b  arranged at a top of the storage tank  12 . In a preferred example, each of the vertical walls  16  and horizontal walls  18  can be the same length with substantially identical cross-sections and curvatures. The interconnected hollow cylindrical walls  14  define a storage chamber  22  suitable for containment of materials including fluids, for example liquid natural gas (LNG), maintained at or above atmospheric pressure. Other fluids, such as gasses, known by those skilled in the art may be stored or contained by tank  12 . Although described and illustrated as a cube with all six sides having equal dimensions, it is understood that the storage tank  12  can take different geometric configurations, for example, rectangular having longer horizontal dimensions and smaller vertical dimensions. Other shapes and configurations known by those skilled in the art may be used. 
         [0037]      FIG. 4  shows the example corner portion  20   a  as viewed from an interior space  295  (best seen in  FIG. 9 ) of the storage tank  12 , and  FIG. 5A  shows the corner portion  20   a  as viewed from the exterior of the storage tank  12 . In the example, the corner portion  20   a  is disposed adjacent each opposing end of the four vertical cylinder walls  16  for a total of eight corner portions  20   a  forming the eight corners of the exemplary cubic storage tank  12 . In the example, a vertical cylinder wall  16  connects to two lower horizontal cylinder walls  18   a . The vertical cylinder wall  16  extends along a substantially vertical longitudinal axis  24 , and the two horizontal cylinder walls  18   a  each extend along an axis  26  and  28 , respectively, at substantially right angles to the axis  24 . The axes  26  and  28  extend at a substantially right angle with respect to one another in a plane orthogonal to the axis  24 , such that the horizontal cylinder walls  18   a  are positioned in a substantially horizontal orientation. The axes  24 ,  26  and  28  intersect at a point (not shown) inside the corner portion  20   a . As generally shown, the vertical cylinder wall  16  and the two horizontal cylinder walls  18   a  extend along their respective axes and are generally connected at their respective distal ends  30 ,  32  and  34  at a joint  40  between the respective cylinder walls, closing off the storage chamber  22 . The joint  40  includes a closure member  60  positioned to close a space or gap between the respective distal ends  30 ,  32  and  34  of the vertical cylinder wall  16  and the two horizontal cylinder walls  18   a , as explained below, although other configurations for the joint  40  are possible. 
         [0038]    In the alternative example of a corner portion  20   b  shown in  FIG. 5B , the vertical cylinder wall  16  and the two horizontal cylinder walls  18   a  are similarly connected at their respective distal ends  30 ,  32  and  34  at a joint  42 . It can be seen that the joint  42  in this example does not include the closure member  60 . In yet another alternative example of a corner portion  20   c  shown in  FIG. 5C , instead of all of the respective distal ends  30 ,  32  and  34  of the vertical cylinder wall  16  and the two horizontal cylinder walls  18   a  meeting at the joint  42 , an end cap  50  abuts portions of the respective distal ends  30 ,  32  and  34  at a joint  44  as generally shown. In the example, end cap  50  is spherical in shape, but other shapes, configurations and joints which will close and form a fluid tight corner known by those skilled in the art may be used. 
         [0039]    In an alternate example not shown, the corners  20  may be rounded or spherical-shaped to more closely match the contour of the cylindrical walls for manufacturing and/or assembly purposes. 
         [0040]    The basic structure for the storage tank  12  is preferably composed of aluminum, although other materials, for example nickel steel, high strength pressure grade steel and other materials, known by those skilled in the art may be used. It is also understood that different components other than those described above and illustrated, as well as in different shapes and orientations, known by those skilled in the art may be used. In a preferred example, during manufacture, the constituent components of the storage tank  12  are rigidly and permanently joined together using a seam welding process in a manner to form a fluid-tight storage chamber  22 . For instance, the joints  40 ,  42  and/or  44  can be completed and sealed to form a fluid tight corner between the vertical  16  and horizontal  18  cylinder walls. The configuration of the completed joints, as well as the processes for completing the joints, may vary according to one or more design, strength, manufacturing and/or other considerations. Examples of these and other joints between constituent parts of the storage tank  12  are explained with reference to  FIGS. 6A and 6B . 
         [0041]      FIG. 6A  is a cross section of the joint  40  in  FIG. 5A  between the vertical wall  16  and a horizontal wall  18   a . According to this example, the storage tank  12  is assembled prior to completing the joint  40  such that a space or gap is present between the respective distal ends  30  and  32  of the vertical wall  16  and the horizontal wall  18   a  prior to completing the joint  40 . As shown, a closure member  60  is sized and configured to substantially close the gap between the respective distal ends  30  and  32 . The closure member  60  extends along the joint  40 , and as can be understood with reference to  FIGS. 4 and 5A , the closure member  60  has three generally annular, open ended ring shaped portions in the example corner portion  20   a . However, the closure member  60  can have other shapes that may vary depending upon its application in alternative corner portions and/or joints between other constituent parts of the storage tank  12 . The closure member  60  can have advantageous use where it is not feasible, cost effective or otherwise desirable to manufacture and/or assemble constituent parts of the storage tank  12  according to tolerances allowing for direct welding. Additionally or alternatively, the closure member  60  may be included to perform a strengthening or reinforcing function in the joint  40 . 
         [0042]    The respective distal ends  30  and  32  of the vertical wall  16  and the horizontal wall  18   a  are chamfered from both an interior side (facing the storage chamber  22 ) and exterior side of the walls, such that a pointed vertex is formed at each of the distal ends  30  and  32 , although the vertexes could alternatively be rounded, for example. The illustrated closure member  60  is shaped with a rectangular cross section and oriented so that pointed vertexes oppose each of the points of the distal ends  56  and  58 . In this configuration, four inwardly tapering grooves are formed. Specifically, two grooves are formed for receiving welds to join the vertical wall  16  to the closure member  60 , and two grooves are formed for receiving welds to join the closure member  60  to the horizontal wall  18   a . The cross section of the closure member  60  can be differently sized or shaped, for example, depending upon the size of the gap to be closed. It will be understood that one or more of the distal ends  30  and  32  and the closure member  60  could be shaped and configured otherwise than specifically illustrated. For instance, the distal ends  30  and  32  and the opposing portions of the closure member  60  could alternatively be rounded, for example, and the distal ends  30  and  32  and the closure member  60  could be formed so that grooves are only formed that open to one of an exterior side or interior side of the walls  16  and  18   a.    
         [0043]      FIG. 6B  is a cross section of the joint  42  in  FIG. 5B  between the vertical wall  16  and a horizontal wall  18   a . According to the example joint  42  illustrated in  FIG. 6B , the storage tank  12  is assembled prior to completing the joint  42  such that respective distal ends  30  and  32  of the vertical wall  16  and the horizontal wall  18   a  to be joined are substantially adjacent and can be continuously seam welded or otherwise mechanically joined together to complete the joint  42 . In the illustrated example, the respective distal ends  30  and  32  of the vertical wall  16  and the horizontal wall  18   a  are chamfered from both the interior side and the exterior side of the walls, such that a pointed vertex is formed at each of the distal ends  30  and  32 . Inwardly tapering grooves are formed by the opposing points of the distal ends  30  and  32 , which are sized and shaped for receiving a weld to join the vertical wall  16  and the horizontal wall  18   a . It will be understood that the distal ends  30  and  32  could alternatively be rounded, for example, or could be formed so that a single groove is formed that opens to only one of the exterior side or the interior side of the walls  16  and  18   a.    
         [0044]    Other configurations and orientations of the joints formed by the intersection of the vertical  16  and horizontal  18   a  cylinder walls at the corners portions known by those skilled in the art may be used. In addition, it will be understood that the illustrated joints are explained with reference to the corner portions only for illustration, and that the examples described are applicable in principle to any other joints or seams between constituent parts of the storage tank  12 . 
         [0045]    The disclosed storage tank containment system  10  includes additional external and/or internal structures configured to efficiently and effectively account for and manage the static and dynamic loads from a fluid contained within the storage tank  12 , as well as the loads from the storage tank  12  itself. 
         [0046]    A representative exterior support structure  100  connected to the outer surfaces of the storage tank  12  is illustrated in a first example with reference to  FIGS. 1-3 ,  7  and  8 . The support structure  100  is generally positioned about an exterior of the walls  14  to provide radial support and/or reinforcement to one or more portions of the storage tank  12 , in order to strengthen the storage tank containment system  10  against stress arising from movement of the fluid within the storage chamber  22 , as well as a stress from the bulk of the storage tank containment system  10  as a whole. The first exemplary support structure  100  includes a plurality of first braces  102  (i.e.,  102   a ,  102   b ,  102   c , etc.), a plurality of second braces  104  (i.e.,  104   a ,  104   b ,  104   c , etc.), and a plurality of third braces  106  (i.e.,  106   a ,  106   b ,  106   c , etc.). A base  150 , further described below, is also used. It will be understood that certain constituent components of the support structure  100  and base  150  that are described and/or illustrated as discrete connected components could be integral, for example, and vice versa. 
         [0047]    In the first example, each of the braces  102 ,  104  and  106  are substantially planar members that extend outward from the storage tank  12  and have interior portions  108  (a representative interior portion  108  is indicated for the brace  102   a ) sized and shaped to closely circumscribe selected exterior portions of the storage tank  12 . In the first example, the braces  102  and  104  are vertically oriented and horizontally spaced, and are aligned at right angles with respect to one another in parallel to the respective edges of the sides of the storage tank  12 . The braces  106  are horizontally oriented and vertically spaced, and are similarly aligned in parallel to the respective edges of the sides of the storage tank  12 . The braces  102 ,  104  and  106  are generally positioned and oriented to reinforce and provide radial support to selected outer portions of the adjacent horizontal and vertical cylinder walls  16  and  18  that respectively form the six sides of the storage tank  12 . 
         [0048]    For instance, in the first example, the braces  102 ,  104  and  106  interconnect to form portions  120  of the support structure  100  that circumscribe the storage tank  12  along the outwardly facing portions of the lower cylinder walls  18   a  that form the upright sides of the storage tank  12 . It can be seen that the components of the portions  120  of the support structure  100  shown can further be shaped and positioned to abut a closure plate  300   b  or  300   c , described in further detail below, as well as additional portions of the storage tank  12 . 
         [0049]    Each of the portions  120  of the support structure  100  comprises vertically oriented braces  102  abutting the outwardly facing portions of two parallel lower cylinder walls  18   a , so as generally circumscribe parts of two opposing upright sides of the storage tank  12 . In the illustrated example, the braces  102  further circumscribe a bottom side of the storage tank  12 . The braces  102  extend vertically to a position approximately at the middle of the two opposing upright sides of the storage tank  12 . The braces  102  are spaced horizontally such that an outer brace  102   c  of the braces  102  is positioned to extend upward along a vertical cylinder wall  16  in a radial direction from the vertical cylinder wall  16 , as well as in abutment with a circumferential portion of a connected horizontal cylindrical wall  18   a.    
         [0050]    The portions  120  similarly comprise vertically oriented braces  104  abutting the outwardly facing portions of the other two parallel lower cylinder walls  18   a , so as generally circumscribe the bottom side of the storage tank  12 , as well as parts of the other two opposing upright sides of the storage tank  12  than the braces  102 . The braces  104  also extend vertically to a position approximately at the middle of the two opposing upright sides of the storage tank  12 . The braces  104  are spaced horizontally such that an outer brace  104   c  of the braces  104  is positioned to extend upward along a vertical cylinder wall  16  in a radial direction from the vertical cylinder wall  16 , as well as in abutment with a circumferential portion of a connected horizontal cylindrical wall  18   a.    
         [0051]    The horizontal braces  106  in this example can optionally rigidly interconnect the braces  102  and braces  104  comprising the portions  120  at each respective upright side of the storage tank  12 . It will be understood that any of the braces  102 ,  104  and  106  can be provided in alternative numbers and/or configurations. For instance, as shown in  FIG. 3A , a brace  106   d  may optionally be configured to substantially circumscribe the storage tank  12 . The brace  106   d  is positioned to extend along the four horizontal cylinder walls  18   a  in a radial direction from the horizontal cylinder walls  18   a , as well as in abutment with circumferential portions of connected vertical cylindrical walls  16 . In addition, it can be seen that certain portions of the braces  106  interconnecting the braces  102  and braces  104  are not included in this variation. 
         [0052]    In addition, central braces  102   a  and  104   b  of the braces  102  and  104  are configured to substantially circumscribe the storage tank  12 . As shown, the central braces  102   a  and  104   b  are positioned to abut the outwardly facing portions of four of the eight cylinder walls  18   a  and  18   b  that extend in parallel, so as generally circumscribe a bottom side of the storage tank  12 , two opposing upright sides of the storage tank  12 , and a top side of the storage tank  12 . It can be seen that the central braces  102   a  and  104   b  intersect at the bottom side and the top side of the storage tank  12  and interconnect the four portions  120  of the support structure  100  circumscribing the outer portions of the four lower cylinder walls  18   a  as described above. 
         [0053]    The concentration of braces  102 ,  104  and  106  toward the lower bottom half of the storage tank  12  are used to fortify the lower portion of the storage tank  12  and its capacity for hydrostatic and other forces. In the second example, T-plates  103  are selectively connected to braces  102  and  104  perpendicular to the braces to form a T-shaped section for increased strength of the braces against buckling and other deformation. As best shown in  FIG. 2 , it is also contemplated that concentrations of braces can be selectively incorporated into the base  150 , for example, at a center of the bottom side of the storage tank  12 . 
         [0054]      FIGS. 3B and 3C  show an optional variation in the configuration of the support structure  100 , wherein the support structure  100  is further designed to provide controlled lateral and vertical support to the storage tank  12  by accommodating the shape of a storage area, such as a cargo hold  160  of a marine carrier  162  (shown in  FIG. 3B  but not in  FIG. 3C  for clarity), into which the storage tank  12  is placed. For example, peripheries  110  (a representative periphery  110  is indicated for the brace  104   a ) sized of the braces  102 ,  104  and  106  opposing the respective portions of the openings  108  that circumscribe the sides of the storage tank  12  can be configured to abut and/or engage upright walls  164  and/or an overhead wall  166  defining the cargo hold  160 . 
         [0055]    Further, or in the alternative, devices for securing the containment system  10  and the storage tank  12  to the cargo hold  160  may be positioned between the walls  164  of the cargo hold  160  and portions of the containment system  10  to inhibit movement of the containment system  10  with respect to the cargo hold  160  in the event, e.g., of a rolling or pitching motion of the carrier  162 . For instance, as shown, chocks  170  are positioned between the upright walls  164  and upright portions of the support structure  100  of the containment system  10 . Further, in the illustrated example, chocks  172  are positioned between the overhead wall  166  and an upper portion of the support structure  100 . The chocks  172  may have advantageous use in the event, e.g., a flooding of the cargo hold  160 , to inhibit the containment system  10  from floating. Although chocks  170  and  172  are shown and described, other devices known by those skilled in the art may be used. 
         [0056]    In a preferred example, first  102 , second  104  and third  106  braces are made from aluminum plate, and the respective openings  108  are sized to conform to the portions of the exterior of the storage tank  12  at which the braces are selectively positioned. It is understood that other materials described above for the walls  14 , and others known by those skilled in the art, may be used. 
         [0057]    The storage tank containment system  10  includes a base  150  for supporting the storage tank  12  on a rigid support surface, for example, a floor  168  of the cargo hold  160 . In one example, base  150  is formed by vertical braces  102  and  104  as best seen in  FIG. 2 . In the example, the peripheries  110  of the vertical braces  102  and  104  opposing the respective portions of the openings  108  that circumscribe the bottom of the storage tank  12  can form a substantially planar platform or surface to form a base  150 , as shown in  FIG. 2 , providing a flat footprint for the storage tank  12  to abut a flat floor  168  of the cargo hold  160 . 
         [0058]    The base  150  can be formed partly or in whole with the braces  102  and  104 , as described above, or can be formed with alternative structures, either alone or in combination with the braces  102  and  104 . The illustrated base  150  is reinforced by an angularly oriented reinforcement skirt  152  adjacent to the bottom sides of the storage tank  12 . As shown in  FIG. 3A , a plurality of rigidly connected reinforcement webs  154  may also be used. 
         [0059]    The base  150 , skirt  152  and/or webs  154  can be shaped similarly to the support structure  100  as described above with reference to  FIGS. 3B and 3C  to accommodate the shape of the cargo hold  160 . For example, the peripheries  110  of the vertical braces  102  and  104  forming the base  150  are chamfered in the variation of  FIGS. 3B and 3C  to approximate the cross section of the cargo hold  160  between the upright walls  164  and the floor  168 . Further, devices for supporting the containment system  10  and the storage tank  12  within the cargo hold  160  may be positioned between the floor  168  of the cargo hold  160  and the base  150 . For instance, as shown, chocks  174  are positioned between the floor  168  and the base  150  of the containment system  10 . Although chocks  174  are shown and described, other devices known by those skilled in the art may be used to support the containment system  10  within the cargo hold  160 . The above described variation is provided as a non-limiting example, and it will be understood that many other variations in the components of the support structure  100  and/or base  150  are possible depending upon the specific configuration of the cargo hold  160 . 
         [0060]    The base  150  is secured to the adjacent storage tank  12  structures in the manner described for the walls  14  and braces  102 ,  104  and  106 . The structures forming the base  150  can be made from the same materials as the braces described above or may be made from other materials and configurations known by those skilled in the art. 
         [0061]    The composition and configuration of the components of the representative exterior support structure  100  may vary according to one or more design, strength, manufacturing and/or other criteria. For example, it is contemplated that the above described exterior support structure  100  can be modified or differently designed according to actual, anticipated and/or simulated static and dynamic loads from a fluid contained within the storage tank  12 , as well as the loads from the storage tank  12  itself. Therefore, it will be understood that variations in the number, placement and orientation of the braces  102 ,  104  and  106  can be made. Similar variations in the construction and materials of the base  150  known by those skilled in the art may be used. One instance of a possible modification to the representative exterior support structure  100  is utilized in a second example of a storage tank containment system  10  shown in  FIGS. 11-19 . 
         [0062]    Referring to  FIGS. 11 and 12 , the support structure  100  in the second example generally includes the first braces  102  (identified with  102   m ,  102   n  and  102   o  in the second example), second braces  104  (identified with  104   m ,  104   n  and  104   o ), and third braces  106  (identified with  106   m ,  106   n  and  106   o ). The base  150  as generally described above with is also used. In the second example, each of the braces  102 ,  104  and  106  are substantially planar members that each defines an interior opening  108  sized to closely circumscribe selected exterior portions of the storage tank  12 . In the example, the braces  102  and  104  are vertically oriented and horizontally spaced, and are aligned at right angles with respect to one another in parallel to the respective edges of the sides of the storage tank  12 . The braces  106  are horizontally oriented and vertically spaced, and are similarly aligned in parallel to the respective edges of the sides of the storage tank  12 . As with the first example, the braces  102 ,  104  and  106  are generally positioned and oriented to reinforce and provide radial support to selected outer portions of the adjacent horizontal and vertical cylinder walls  16  and  18  that respectively form the six sides of the storage tank  12 . 
         [0063]    In the second example, each of the braces  102 ,  104  and  106  are configured to substantially circumscribe the storage tank  12 . In relation to a single side of the storage tank  12 , two outer braces  102   m  and  102   o  of the braces  102  are each positioned to extend upward along a vertical cylinder wall  16  in a radial direction from the vertical cylinder wall  16 , as well as in abutment with circumferential portions of connected horizontal cylindrical walls  18   a  and  18   b . Similarly, two outer braces  104   m  and  104   o  of the braces  104  are each positioned to extend upward along a vertical cylinder wall  16  in a radial direction from the vertical cylinder wall  16 , as well as in abutment with circumferential portions of connected horizontal cylindrical walls  18   a  and  18   b . Finally, two outer braces  106   m  and  106   o  of the braces  106  are each positioned to extend horizontally along a horizontal cylinder wall  18  in a radial direction from the horizontal cylinder wall  18 , as well as in abutment with circumferential portions of connected vertical cylindrical walls  16 . 
         [0064]    Although the outer of the braces  102 ,  104  and  106  are described for clarity in relation to a single face of the storage tank  12 , it will be understood from the Figures that the outer of the braces  102 ,  104  and  106  may be configured to circumscribe multiple faces of the storage tank  12 . For instance, it can be seen that the outer of the braces  102 ,  104  and  106  can circumscribe four faces of the storage tank  12  to generally form a loop around the storage tank  12 , with four constituent portions each positioned and oriented similarly in principle to those described above with respect to a single face. 
         [0065]    Central braces  102   n  and  104   n  are positioned to abut the outwardly facing portions of four of the eight cylinder walls  18   a  and  18   b  that extend in parallel, so as generally circumscribe a bottom side of the storage tank  12 , two opposing upright sides of the storage tank  12 , and a top side of the storage tank  12 . Central brace  106   n  is positioned to abut the outwardly facing portions of the four vertical cylinder walls  16 , so as generally circumscribe all four upright sides of the storage tank  12 . The central braces  102   n ,  104   n  and  106   n  can span spaces  290  on the sides of the storage tank  12  created between the spaced cylinder walls  14 . However, the medial brace can further be shaped and positioned to abut a closure plate  300   c , described in further detail below. 
         [0066]    It can be seen that the braces  102 ,  104  and  106  positioned as described and shown can be rigidly interconnected at their respective intersections to form a reinforcing lattice structure around the storage tank  12 . In one variation of the second example of the representative exterior support structure  100  not shown, it is contemplated that one or more of the upper braces  106  can be reduced in load bearing capacity due to the gradual reduction in hydrostatic forces placed on the storage tank  12  by its contents. For example, because the hydrostatic load on an interior of the walls  14  will be greater nearer the base  150 , a support structure  100  including a plurality of horizontally oriented braces  106  can include a first brace  106  relatively stronger than a second brace  106  positioned further from the base  150  than the first brace  106 . It is further contemplated, however, that depending on the application, such gradual reduction in hydrostatic forces may be offset by anticipated dynamic loading in certain applications. 
         [0067]    Like the first example, the first  102 , second  104  and third  106  braces of the second example are made from aluminum plate, and the respective openings  108  are sized to conform to the portions of the exterior of the storage tank  12  at which the braces are selectively positioned. It is understood that other materials described above for the walls  14 , and others known by those skilled in the art, may be used. 
         [0068]    The disclosed storage tank containment systems  10  of the first and second examples further includes internal structures configured for the storage and management of fluid within the storage chamber  22 , or elsewhere, as described below, as well as for further reinforcement of the storage tank  12 . It will be understood that the various internal structures and other features described below with reference to one or both of the first and second examples of the storage tank containment system  10  can be used in any combination with each other, as well as in further combination with one or more features of the above described examples of the support structure  100 . 
         [0069]    In a preferred example of a containment system  10  for storing liquids, such as LNG, the storage tank  10  can include bulkhead structures  200   a ,  200   b ,  200   c  and/or  200   d  positioned within and secured to the storage chamber  22 , as shown in  FIGS. 7 ,  13 ,  17  and  18 , respectively. The bulkhead structures  200  are located in each of the horizontal tubular walls  18  as generally shown in the Figures for deterring or easing the sloshing or dynamic movement of the fluid contained in the storage chamber  22 . In a preferred example, each bulkhead  200  is positioned and secured to the adjacent walls  18  substantially midstream of a horizontal tube  18 . As explained above, the sloshing movement of liquid contained in the walls  14  creates a corresponding dynamic load on the interior of the walls  14 . The bulkhead structures  200  provides an internal structure to partially obstruct flow of the liquid contained in the horizontal walls  18 , which reduces the extent of sloshing and lowers the magnitude of the dynamic loads received by the ends of the horizontal walls  18 . In addition, it will be understood that all or part of the bulkhead structures  200  may be configured to perform a reinforcing function of the cylindrical cross section of the wall  14 . 
         [0070]    As shown in  FIG. 7 , an exemplary bulkhead structure  200   a  includes a substantially planar plate  204  configured to span a cross section of the horizontal walls  18  defining a portion of the storage chamber  22 . In the example, the planar plate  204  defines a plurality of ovoid apertures  206  arranged in an “x” pattern about the plate  204  to permit fluid communication on either side of the plate  204 . 
         [0071]    A material of an outer periphery  204   a  of the planar plate  204  may be relatively more rigid than a material of an inner portion  204   b  of the planar plate  204 . In this arrangement, the outer periphery  204   a  of the planar plate  204  performs a reinforcing function for the cylindrical cross section of the wall  14 , while the inner portion  204   b  acts as a membrane to partially obstruct flow of the liquid contained in the horizontal walls  18  by, for example, defining the apertures  206  as shown. Although it is understood that a variety of materials in varying thicknesses may be used, in an application of tank system  10  in the size example noted above for containing LNG, a thickness of an aluminum material forming the plate  204  may be approximately 4-5 inches at the outer periphery  204   a , while the inner portion  204   b  may be approximately 1-2 inches thick. In this example, a plurality of cross members  208  may be further provided to reinforce the inner portion  204   b  against a dynamic loading normal to the planar plate  204  arising from a flow of liquid contained in the horizontal walls  18 . 
         [0072]    It is understood that alternate configurations for the planar plate  204  can be used, and that more or fewer apertures may be used and that the apertures  206  can have any suitable polygonal or rounded profile to suit the particular contents or application as known by those skilled in the art. For instance, the planar plate  204  may be configured with substantially uniform thickness. In addition, in the example bulkhead structure  200   b  shown in  FIG. 13 , each plate  204  defines six rectangular apertures  206  arranged in two rows of three apertures  206 . In another example of a bulkhead structured  200   c  shown in  FIG. 17 , a plurality of polygonal apertures  206  are arranged about a periphery of the planar plate  204 . In the example of a bulkhead structured  200   d  shown in  FIG. 18 , a plurality of polygonal apertures  206  are arranged uniformly about the planar plate  204 . 
         [0073]      FIGS. 15 and 16  show examples of horizontal, cut-away sections of the containment system  10  illustrating an example of a corner reinforcement  250  provided to reinforce the interior of corner portions  20 . Referring to  FIG. 15 , a corner reinforcement  250  positioned in a bottom corner portion  20  of the storage tank  12  includes a first plate  252 , a second plate  254  and a third plate  256  (angularly positioned below and extending downward from the first and second plate). The first  252 , second  254  and third  256  plates span respective portions of the corner portion  20  and connect to the respective inner walls of the corner portion  20  inside storage chamber  22  as best seen in  FIG. 16  (showing all four lower corner portions  20  having a corner reinforcement  250 ). It is understood some or all of the corner portions  20  may include a corner reinforcement  250 , and that one or more of the corner reinforcements  250  may not be needed depending on the application. 
         [0074]    In a preferred example shown, a first plate first edge  258 , a second plate first edge  260  and a third plate first edge  262  each connect to the corner  20  along the adjacent joint  30  formed by a vertical wall  16  and horizontal walls  18 . The first plate  252 , second plate  254  and third plate  256  connect at a joint  264 . In one example, first  252 , second  254  and third  256  plates are spaced 120 degrees apart. It is understood that corner reinforcements  250  may take other configurations, plate or web formations to suit the particular application as known by those skilled in the art. 
         [0075]    In the example bulkhead structure  250 , each of the first plate  252 , second plate  254  and third plate  256  define respective through apertures  270 ,  272  and  274  to permit fluid communication on either side of the plates, such that portions of the storage chamber  22  are not blocked off otherwise compartmentalized. As shown in  FIG. 17 , a bulkhead structure  250  can be positioned in each top corner portion  20  of the storage tank  12 . It will be understood by those skilled in the art that other configurations and orientations for the bulkhead structure  250  may be used, and other reinforcements may be positioned in a corner portion  20 . 
         [0076]    Referring to  FIG. 19 , an alternate example of a corner reinforcement  440  is shown. In the example, tank corner  20  reinforcement  440  is in the form of a plate  445  (only one-half of the plate shown in the sectional view in  FIG. 19 ) defining an interior aperture  450  (surrounded by plate material  445 ). In the example, the plate  445  is angled at approximately 45 degrees and is seam welded on its ends, or alternately all around its perimeter to adjacent walls of the corner portion  20  and the adjacent vertical  16  and horizontal  18  cylindrical walls. The aperture  450  serves to reduce weight and provide resistance to sloshing of the stored fluid as described above. Other forms, configurations, orientations and positions of corner reinforcements to suit the particular application known by those skilled in the art may be used. 
         [0077]    The material used to construct the storage tank  12  as described above may be used to construct the bulkheads  200 ,  250  and  440 . In one example, the illustrated bulkheads  200 ,  250  and  440  are rigidly and continuously seam welded to the storage tank  12 . 
         [0078]    It will be understood that the illustrated corner reinforcements  250  and  440  may not be necessary or desirable in certain applications. Certain disclosed embodiments, for example the embodiment of  FIGS. 1-10  with the first example of the exterior support structure  100 , may not include corner reinforcements, as can be seen with reference to  FIGS. 7-9 . In this and other examples, the reinforcing function of the illustrated corner reinforcements  250  and  440 , if desired, may be performed by other aspects of the storage tank  12  and/or exterior support structure  100 . 
         [0079]    In the example of the storage tank  12  described and illustrated above, the twelve cylindrical tubular walls  16  and  18  are closed sectioned, forming an interior storage chamber  22 . In this example, openings  290  form on each of the six sides of the tank  12 , leading to an interior space  295  between the interior facing walls of the cylinders. In the examples of the storage tank containment system  10  shown throughout the Figures, the openings  290  are sealed closed and the interior space  295  is placed in fluid communication with the storage chamber  22  inside the cylinders to utilize the interior space  295  as additional storage for the fluid, as explained below. 
         [0080]    With representative reference to  FIG. 19 , it can be seen that closure plates  300   a  and interior facing portions of the cylinder walls  16  and  18   a  (e.g., an interior portion  310  of a vertical cylinder wall  16  and interior portion  312  of a horizontal cylinder wall  18   a  are indicated) may be used to seal off and define an interior storage chamber  302  defined by the closure plates  300  and interior wall portions  310  and  312  of the cylinder walls  16  and  18   a  forming the storage tank  12 . 
         [0081]    A number of configurations of closure plates  300  are shown throughout the Figures, which are explained with additional reference to  FIGS. 10A-C . In the example shown in  FIG. 10A , the closure plate  300   s  is planar and configured to extend normally between adjacent walls  14 . In an alternate example shown in  FIG. 10B , closure plate  300   b  is spherical or rounded and generally extends between adjacent walls  14 , but at a position further outward of an imaginary line connecting longitudinal axes of adjacent walls  14 . In the alternate example shown in  FIG. 10C , closure plate  300   c  is also spherical or rounded, but extends between adjacent walls  14  at an outer portion of the walls  14 , such that the closure plate  300   c  extends generally tangentially between adjacent walls  14 . 
         [0082]    Through use of the closure plates  300   a ,  300   b  or  300   c , and corresponding use of interior space  295  for storage, increased storage capacity is achieved. In one example of a tank with dimensions described above, the volumetric storage efficiency of tank system  10 , as compared to a similarly dimensioned cube, increases from about 0.81 to 0.88, which is far superior to prior designs. 
         [0083]    The storage tank containment system  10  may be configured to include only one type of the closure plates  300   a ,  300   b  and  300   c , for example, or may be configured to include a mixture of the closure plates  300   a ,  300   b  and  300   c , as well as other closure plates not specifically illustrated. Closure plates  300   a ,  300   b  and  300   c  can be made from the materials used for the walls  16 ,  18   a  as described above. It will be understood by those skilled in the art that other configurations, orientations for the closure plates  300   a ,  300   b  and  300   c  may be used to seal and define an interior storage chamber  302 . 
         [0084]    As best seen in  FIG. 9 , in one example described above where the cylindrical walls  14  are closed-sectioned and the interior storage chamber  22  serves as the only storage area, the cylindrical walls  16  and  18   a  have exterior portions  320  and  322 , respectively, for example the outer half or circumference of the circular cross-section which faces toward the exterior of the tank, and respective interior portions  310  and  312 . As shown in  FIG. 9 , the respective first and second wall portions may be defined by or positioned near the location of the closure plates  300   a . As shown in  FIG. 9 , liquid contained in the storage chamber  22  exerts a radial hydrostatic force F1 to an interior  310  of the vertical cylinder wall  16 . The load bearing capacity of the vertical cylinder wall  310 , 320  must be sufficient to account for the force F1. Where closure plates  300   a  are not employed and the interior chamber  302  (or space  295 ) is not utilized for storage, the interior wall portions  310  must withstand similar loads as the exterior wall portions  320  and require substantially similar construction. In an application of tank system  10  in the size example noted above for containing LNG, the thickness of walls  16  and  18  for aluminum are estimated to be between 1 and 6 inches thick. For steel, a thickness of 0.5-4 inches may be used. Other thicknesses, depending on the material used and application, known by those skilled in the art may be used. 
         [0085]    However, where closure plates  300   a  (or closure plates  300   b  or  300   c ) are employed and the interior storage space  302  utilized, the inclusion of a liquid in the interior storage chamber  302  will create an opposing radial hydrostatic force F2 to the opposite side of the vertical cylinder wall portion  310  that partially defines the interior storage chamber  302 . Because the hydrostatic force F2 counteracts and counterbalances the hydrostatic force F1, the load bearing capacity and corresponding thickness of the vertical cylinder wall  16  and horizontal cylinder wall  18   a  can be reduced in the respective wall portions  310  and  312 , which reduces the mass and the material cost of the storage tank  12 . 
         [0086]    In the example of the storage tank  12  utilizing only storage chamber  22  within the cylinder walls  14 , one or more ports in the exterior of the walls (not shown) in communication with interior chamber  22  can be used to fill or withdraw fluid from the storage chamber  22 . Where interior storage chamber  302  is used along with storage chamber  22 , one or more ports (not shown), for example on wall portions  310  and/or  312  can be provided in the appropriate walls  14  to provide fluid communication between the storage chamber  22  and the interior storage chamber  302 . 
         [0087]    Referring to  FIG. 18 , an example of first gusset plates  400  (two shown) are illustrated. In the example, each gusset plate  400  is positioned between the vertically adjacent horizontal tube walls  18  in the interior chamber  302  and are rigidly connected thereto. Each gusset plate  400  may include one or more aperture  410  (two shown) to permit the flow of fluid through the gusset plate to deter sloshing of fluid in interior chamber  302  as generally described for bulkheads  200  described above. In one example, the gusset plates are rigid planar plates, but may take other forms and configurations to suit the application as known by those skilled in the art. 
         [0088]    As also seen in  FIG. 18 , one or more second gusset plates  420  are positioned between and rigidly connected to the first gusset plates  400  and the horizontal cylinders  18  as generally shown. In the example, second gussets  420  preferably have a plurality of similar apertures  425  to permit a restricted flow of fluid to deter sloshing of the fluid inside the interior chamber  302 . The first  400  and second  420  gussets provide both structure reinforcement and deter sloshing of fluid inside the chamber  302 . Other gussets, reinforcement plates and sloshing deterring structures known by those skilled in the field may be used. For example, as seen in  FIG. 19 , the second gusset plates  420  are used without the first gusset plates  400 . In the example, the second gusset plates  420  are rigidly connected to the four adjacent horizontal cylinder walls  18  and further include a third gusset plate  430  which is generally shown in a horizontal position between the generally vertically-oriented second gusset plates  420 . 
         [0089]    As further seen in  FIGS. 7 and 8 , gusset plates  502  and  504  can be positioned between and rigidly connected to vertically adjacent parallel horizontal cylinder walls  18  in the interior chamber  302 , while a gusset plates  506  is positioned between and rigidly connected to horizontally adjacent parallel vertical cylinder walls  16 . In addition, the gusset plates  502 ,  504  and  506  are connected at their respective intersections. Each of the gusset plates  502 ,  504  and  506  extend in a plane passing through a center of the storage tank  12 . The gusset plates  502  and  504  extend vertically in parallel with respective opposing side faces of the storage tank  12 , and discontinue at an intersection with the walls  14 , as well at an intersection with respective adjacent gusset plates. The gusset plate  506  extends horizontally in parallel with opposing top and bottom faces of the storage tank  12 , and also discontinues at an intersection with the walls  14 , as well as at an intersection with respective adjacent gusset plates. Only three gusset plates  502 ,  504  and  506  out of eight total gusset plates are indicated and described for clarity. It can be seen and understood that the other of the gusset plates are positioned and configured similarly to the gusset plates  502 ,  504  and  506 . 
         [0090]    As shown, the gusset plates  502 ,  504  and  506  can be rigidly interconnected at their intersections, as well as interconnected with the support structure  100 . As shown, the vertically disposed gusset plates  502  and  504  connect to the central vertical braces  104   a  and  102   a , respectively, while the horizontally disposed gusset plate  506  connects to the horizontal brace  106   a . The gusset plates  502 ,  504  and  506  can fluidly compartmentalize the interior chamber  302 , or as explained above, may include one or more apertures (not shown in this example) to permit a flow of fluid. 
         [0091]    Referring to  FIGS. 13 and 15 , one example of a device for filling and extracting fluid from tank  12  is in the form of a filling tower  350 . In the example, tower  350  includes a substantially horizontal hollow tube  352  connected to a substantially vertical hollow tube  354 . The vertical tube  354  includes an intake port  356  positioned near the top of the storage tank  12 , or extending therefrom, and is configured to connect to a remote fluid source, such as a transfer pump (not shown) or other devices known by those skilled in the art. 
         [0092]    As shown in  FIG. 15 , the horizontal tube  352  can connect to and through one or more of the cylinder horizontal walls  18  to provide fluid communication between the intake port  356  and the storage chamber  22 . In the example, the vertical tube  354  is supported by a plurality of support brackets or structures  358  which preferably permit fluid communication on either side of the support structures  358 . The vertical tube  354  can include one or more ports (not shown) to provide fluid communication between the intake port  356  and the interior storage chamber  302 . Alternately, through ports (not shown) may be used through the interior portions of walls tubular walls  16   b  and/or  18   b  to ease the flow of fluid into and out of the tank  12 . The filling tower  350  can also be used to extract a fluid from the storage chamber  12  and the interior storage chamber  302 . It is understood that other tubes, pipes or ports may be used to permit the rapid, high volume flow of fluid into and out of the tank  12  to facilitate filling and extracting the fluid known by those skilled in the art may be used. 
         [0093]    It will be understood that the above described embodiments, features and examples of the structures and features of the storage tank containment system  10  may be altered and/or combined in a wide variety of manners according to one or more design, strength, manufacturing, cost and/or other criteria.  FIG. 7  is illustrative of the features of the storage tank containment system  10  in the first example that incorporates certain of the above described inventive external, internal, and other structures for the storage tank  12  in what is presently considered to be a preferred arrangement. 
         [0094]    In the first example, the storage tank containment system  10  includes the storage tank  12  having the above described corner portions  20   a  formed in combination with the closure member  60  as shown in  FIGS. 4 ,  5 A and  6 A. The support structure  100  and base  150  are constructed in accordance with the discussion of  FIGS. 1-3 ,  7  and  8 . As shown, the example further includes internal structures configured for the storage and management of fluid within the storage chamber  22  and elsewhere. For example, the storage tank containment system  10  includes the bulkhead structure  200   a , wherein the planar plate  204  is composed of the reinforcing outer periphery  204   a  and the membrane inner portion  204   b  configured to partially obstruct a flow of liquid by defining the ovoid apertures  206 . The interior space  295  is defined in part with the closure plates  300   b , and houses the crossing gusset plates  502 ,  504  and  506  positioned between and rigidly connected to the walls  14 . 
         [0095]    The exemplary storage tank  12  has dimensions of 150 feet (f) or 50 meters (m) per geometric side. In an application of storing LNG, the thickness of aluminum plate forming the bottom horizontal cylinder walls  18  can vary between approximately 2-5 inches, the thickness of aluminum plate forming the top horizontal cylinder walls  18  can vary between approximately 0.5-3 inches, the thickness of aluminum plate forming the vertical horizontal cylinder walls  16  can vary between approximately 2-4 inches, the thickness of aluminum plate forming the bottom corner portions  20  can vary between approximately 3-6 inches, and the thickness of aluminum plate forming the top corner portions  20  can vary between approximately 1-3 inches. Aluminum forming the closure plate  300   b  can vary in thickness between approximately 2-4 inches. Aluminum forming the closure member  60  can vary in thickness between approximately 4-6 inches at the bottom corner portions  20 , and between 3-4 inches at the top corner portions  20 . 
         [0096]    The thickness of aluminum plate forming the components of the support structure  100  and the above described internal structures and reinforcements can generally vary between approximately 1-3 inches. Certain portions of the support structure  100 , for example the T-plates  103  and reinforcing outer periphery  204   a  of the planar plate  204 , can formed from aluminum plate with a thickness varying between approximately 3-6 inches. 
         [0097]    These dimensions are based on one contemplated design case and are given as a non-limiting example. It will be understood that other thicknesses, depending on the material used and application, may be used. 
         [0098]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.