Patent Application
20160319990
The embodiments disclosed herein generally pertain to storage tanks and more particularly to storage tanks for fluids including liquids and gases.
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.
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.
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.
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 '106 tank was more rigid using one third the wall thickness of the geometric cube. The '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. It was further determined, however, that the '106 configured tank could be improved.
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.
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.
Disclosed herein are embodiments of a large volume natural gas storage tank.
In one aspect, a large volume natural gas storage tank comprises rigid tubular walls having opposing ends and intermediate segments with closed tubular cross-sections and interconnected at both ends with respective ends of two other rigid tubular walls such that interconnected interiors of the rigid tubular walls define an interior fluid storage chamber; bulkheads positioned in the interior fluid storage chamber across the intermediate segments of the rigid tubular walls; closure plates connected between exterior surfaces of successive interconnected rigid tubular walls to define sides of the storage tank, wherein interior surfaces of the closure plates and the exterior surfaces of the rigid tubular walls define an auxiliary fluid storage chamber; and exterior support structures extending through the closure plates and between the exterior surfaces of the successive interconnected rigid tubular walls on at least some of the sides of the storage tank configured to reinforce the storage tank against dynamic loading from fluid in the interior fluid storage chamber.
In another aspect, a large volume natural gas storage tank comprises rigid tubular walls having opposing ends and intermediate segments with closed tubular cross-sections and interconnected at both ends with respective ends of two other rigid tubular walls such that interconnected interiors of the rigid tubular walls define an interior fluid storage chamber; bulkheads positioned in the interior fluid storage chamber across the intermediate segments of the rigid tubular walls, each bulkhead comprising an annular planar plate connected with an interior of one of the rigid tubular walls and defining an aperture to permit a restricted flow of fluid through the bulkhead; closure plates connected between exterior surfaces of successive interconnected rigid tubular walls to define sides of the storage tank, wherein interior surfaces of the closure plates and the exterior surfaces of the rigid tubular walls define an auxiliary fluid storage chamber; and exterior support structures extending from the closure plates, through the exterior surfaces of the successive interconnected rigid tubular walls, to the bulkheads on at least some of the sides of the storage tank, the exterior support structures configured to reinforce the storage tank against dynamic loading from fluid in the interior fluid storage chamber.
In yet another aspect, a large volume natural gas storage tank comprises rigid tubular walls having opposing ends and intermediate segments with closed tubular cross-sections and interconnected at both ends with respective ends of two other rigid tubular walls such that interconnected interiors of the rigid tubular walls define an interior fluid storage chamber; bulkhead ring webs positioned in the interior fluid storage chamber across the intermediate segments of the rigid tubular walls, each bulkhead ring web comprising an annular planar plate connected with an interior of one of the rigid tubular walls and defining an aperture to permit a restricted flow of fluid through the bulkhead ring web; closure plates extending normally between exterior surfaces of successive interconnected rigid tubular walls to define vertical sides of the storage tank, wherein interior surfaces of the closure plates and the exterior surfaces of the rigid tubular walls at least partially define an auxiliary fluid storage chamber; exterior support structures comprising rigidly interconnected vertical and horizontal braces, the braces extending between the exterior surfaces of the successive interconnected rigid tubular walls and outward through the closure plates on the vertical sides of the storage tank; and blocks disposed on the braces outward of the exterior surfaces of the closure plates on the vertical sides of the tank, the blocks configured to maintain the storage tank in an installation position when abutting brackets extending from a cargo hold of a carrier.
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.
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
Examples of storage tank containment systems 10 are shown in
The exemplary storage tank 12 includes four vertically oriented cylinder walls 16 positioned approximately 90 degrees apart from one another and eight horizontally oriented cylinder walls 18 disposed between, and rigidly connecting to, the ends of the vertical walls 16 at corner portions 20a. As shown, the eight horizontal cylinder walls 18 include four lower cylinder walls 18a arranged at a bottom of the storage tank 12 and four upper cylinder walls 18b 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 cylinder walls 14 define an interior fluid 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.
The axes 24, 26 and 28 intersect at a point (not shown) inside the corner portion 20a. As generally shown, the vertical cylinder wall 16 and the two horizontal cylinder walls 18a 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 interior fluid 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 18a, as explained below, although other configurations for the joint 40 are possible.
In the alternative example of a corner portion 20b shown in
In an alternate example not shown, the corners 20 may be rounded or spherical-shaped to more closely match the contour of the cylinder walls for manufacturing and/or assembly purposes.
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 interior fluid 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
The respective distal ends 30 and 32 of the vertical wall 16 and the horizontal wall 18a are chamfered from both an interior side (facing the interior fluid 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 18a. 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 18a.
Other configurations and orientations of the joints formed by the intersection of the vertical 16 and horizontal 18a 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.
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 as further described below.
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
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 openings 108 (a representative opening 108 is indicated for the brace 102a) 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.
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 18a 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 300b or 300c, described in further detail below, as well as additional portions of the storage tank 12.
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 18a, 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 102c 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 cylinder wall 18a.
The portions 120 similarly comprise vertically oriented braces 104 abutting the outwardly facing portions of the other two parallel lower cylinder walls 18a, 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 104c 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 cylinder wall 18a.
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
In addition, central braces 102a and 104b of the braces 102 and 104 are configured to substantially circumscribe the storage tank 12. As shown, the central braces 102a and 104b are positioned to abut the outwardly facing portions of four of the eight cylinder walls 18a and 18b 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 102a and 104b 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 18a as described above.
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
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.
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.
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
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
The base 150, skirt 152 and/or webs 154 can be shaped similarly to the support structure 100 as described above with reference to
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.
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.
For example, as shown in
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 300b 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.
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 204a of the planar plate 204, can formed from aluminum plate with a thickness varying between approximately 3-6 inches.
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
Referring to
In the second 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.
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 102m and 102o 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 cylinder walls 18a and 18b. Similarly, two outer braces 104m and 104o 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 cylinder walls 18a and 18b. Finally, two outer braces 106m and 106o 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 cylinder walls 16.
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.
Central braces 102n and 104n are positioned to abut the outwardly facing portions of four of the eight cylinder walls 18a and 18b 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 106n 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 102n, 104n and 106n 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 300c, described in further detail below.
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.
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.
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 interior fluid 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.
In a preferred example of a containment system 10 for storing liquids, such as LNG, the storage tank 10 can include bulkhead structures 200a, 200b, 200c and/or 200d positioned within and secured to the interior fluid storage chamber 22, as shown in
In one example, each bulkhead 200 is positioned and secured to the adjacent horizontal cylinder walls 18 in a substantially midstream location. 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 provide an internal structure to partially obstruct flow of the liquid contained in the horizontal cylinder walls 18, which reduces the extent of sloshing and lowers the magnitude of the dynamic loads received by the ends of the horizontal cylinder 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 walls 14.
As shown in
A material of an outer periphery 204a of the planar plate 204 may be relatively more rigid than a material of an inner portion 204b of the planar plate 204. In this arrangement, the outer periphery 204a of the planar plate 204 performs a reinforcing function for the cylindrical cross section of the wall 14, while the inner portion 204b 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 204a, while the inner portion 204b 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 204b against a dynamic loading normal to the planar plate 204 arising from a flow of liquid contained in the horizontal walls 18.
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 200b shown in
In one example, 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 cylinder wall 16 and horizontal cylinder 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.
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 interior fluid storage chamber 22 are not blocked off otherwise compartmentalized. As shown in
Referring to
Other forms, configurations, orientations and positions of corner reinforcements to suit the particular application known by those skilled in the art may be used. 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.
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
In the example of the storage tank 12 described and illustrated above, the twelve cylinder walls 16 and 18 are closed sectioned, forming an interior fluid 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 interior fluid storage chamber 22 inside the cylinders to utilize the interior space 295 as additional storage for the fluid, as explained below.
With representative reference to
A number of configurations of closure plates 300 are shown throughout the Figures, which are explained with additional reference to
Through use of the closure plates 300a, 300b or 300c, and corresponding use of interior space 295 for storage, increased storage capacity is achieved. In one example of a tank 12 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. Further, when using closure plates 300b, 300c connected at positions increasingly outboard of the center of the tank 12, heat losses are reduced, that is, less of the exterior surface of the tank 12 includes bends and corners prone to acting as heat sinks.
The storage tank containment system 10 may be configured to include only one type of the closure plates 300a, 300b and 300c, for example, or may be configured to include a mixture of the closure plates 300a, 300b and 300c, as well as other closure plates not specifically illustrated, such as triangular or l-shaped closure plates. Closure plates 300a, 300b and 300c can be made from the materials used for the walls 16, 18a as described above. It will be understood by those skilled in the art that other configurations and orientations for the closure plates 300a, 300b and 300c may be used to seal and define an auxiliary storage chamber 302.
As best seen in
As further shown in
However, where closure plates 300a (or closure plates 300b or 300c) are employed and the auxiliary storage chamber 302 utilized, the inclusion of a liquid in the auxiliary 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 auxiliary 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 18a can be reduced in the respective wall portions 310 and 312, which reduces the mass and the material cost of the storage tank 12.
In the example of the storage tank 12 utilizing only interior fluid 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 interior fluid storage chamber 22. Where auxiliary storage chamber 302 is used along with interior fluid 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 interior fluid storage chamber 22 and the auxiliary storage chamber 302.
Referring to
As also seen in
As further seen in
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 104a and 102a, respectively, while the horizontally disposed gusset plate 506 connects to the horizontal brace 106a. The gusset plates 502, 504 and 506 can fluidly compartmentalize the auxiliary storage chamber 302, or as explained above, may include one or more apertures (not shown in this example) to permit a flow of fluid.
Referring to
As best shown in
The filling tower 350 can also be used to extract a fluid from the interior fluid storage chamber 22 and the auxiliary storage chamber 302. To optimize extraction, the outlet port 357 can be located in near proximity to an interior surface of the bottommost closure plate 300b when the tank 12 is in an installed position. The closure plate 300b can be shaped to leverage gravity when extracting fluid from the auxiliary storage chamber 302. As shown in
Referring to
The other exterior support structure 100 in
Interior surfaces of the closure plates 300a, interior surfaces of the exterior support structures 100, and exterior surfaces of the plurality of rigid cylinder walls 16, 18 can be used to define an auxiliary storage chamber 302 similar to that described in reference to
The exterior support structures 100 in
Some of the blocks 600 are also disposed on support surfaces 604 of the exterior support structures 100, the support surfaces 604 extending from the exterior surface of one of the bottommost rigid cylinder walls 18 when the storage tank 12 is in an installation position within a cargo hold of a carrier to the respective closure plate 300a covering the respective exterior support structure 100. The support surfaces 604 and coupled blocks 600 are configured to abut ledges extending from a cargo hold in a carrier to maintain the storage tank in the installation position as further described in reference to
Further, each bulkhead 200 extends outward from the exterior surfaces of the opposing horizontal rigid cylinder walls 18 between sections of the bottommost closure plate 300a to form a base 150 for the storage tank. The base 150 of the storage tank 12 is configured to support the storage tank 12 in an installation position within a cargo hold of a carrier. In the example of
In one non-limiting example, the support surfaces 604 can be angled between 25 and 40 degrees above the horizontal plane, in order to optimize support for the storage tank 12. For example, angled support surfaces 604 can rest on a ledge extending from the cargo hold as shown in
Additional blocks 600 can extend from the base 150 and from the support surfaces 604 on the lower side of opposing exterior support structures 100 in order to rest, respectively, on a bottom surface and a skirt or ledge 608 extending from the upright walls 164 of the cargo hold 160. The ledge 608 can be configured to support the weight of the tank 12 in the carrier 162 when the tank 12 is in an installation position. By angling the support surfaces 604, and optionally the blocks 600 extending from the support surfaces 604, any variations in dimension of the cargo hold 160 can be accounted for in the design of the tank 12. This is important given the temperature differential between the tank 12 and the carrier 162 as well as the vast size of the tank 12 and the cargo hold 160.
A single bulkhead 200 is also shown in
In the third example of
Referring to
The storage tank 12 in this fourth example includes rigid tubular walls 16, 18 having opposing ends and intermediate segments with closed tubular cross-sections that are interconnected at both ends with respective ends of two other rigid tubular walls 16,18 such that interconnected interiors of the rigid tubular walls 16, 18 define an interior fluid storage chamber (not shown). The storage tank 12 also includes closure plates 300a, 300d connected between exterior surfaces of successive interconnected rigid tubular walls 16, 18 to define sides of the storage tank 12. Interior surfaces of the closure plates 300a, 300d and the exterior surfaces of the rigid tubular walls 16, 18 at least partially define an auxiliary fluid storage chamber (not shown) similar to those described in reference to
Two types of closure plates 300a, 300d are shown in
In the case of the vertical sides shown in
In the case of the topmost side, the closure plate 300d extends between the exteriors of the successive interconnected rigid tubular walls 16, 18 at a location exterior to the maximum outer dimension. In other words, the closure plate 300d is spaced slightly outward of the maximum outer dimension on the topmost side of the storage tank 12. Often, the overall height of a cargo hold can be greater than its width, allowing more leeway in the location of the closure plate 300d. Both of the closure plates 300a, 300d are shown as having planar or flat exterior surfaces, though other shapes are possible. For example, spherical, rounded, triangular, or l-shaped closure plates could be used to form the outer limits of the auxiliary storage chamber.
Two exterior support structure 100a and 100b are shown in
The exterior support structures 100a, 100b not only extend through the closure plates 300a but also extend in an outward direction from exterior surfaces of the closure plates 300a, the outward direction being in reference to a center of the storage tank 12. Thus, the exterior support structures 100a, 100b are configured to reinforce the storage tank 12 against dynamic loading from fluid in the interior fluid storage chamber and provide surfaces useful for mounting and location restriction of the storage tank 12 as further described in reference to
The blocks 600 are positioned in a manner configured to maintain the storage tank 12 in an installation position when serving as spacers or when abutting brackets, stops, or other structures extending from a cargo hold of a carrier. The blocks 600 can be formed of marine-grade, laminated, densified wood and adhesively bonded to the closure plates 300a, 300d and the braces 102, 104, 106 using, for example, epoxy. Other high-strength materials can also be used for the blocks 600. Though the blocks 600 in
The closure plates 300d extending along the topmost side and the bottommost side of the storage tank 12 both extend outward or beyond a maximum outer dimension for the successive interconnected rigid tubular walls 16, 18 on the topmost side and the bottommost side. The closure plate 300d on the topmost side of the storage tank 12 has a shorter height than the closure plate 300d on the bottommost side of the storage tank 12, though the heights could be equal or opposite in value depending on the position and structure of the auxiliary fluid storage chamber. The volume of the auxiliary fluid storage chamber is tied to the placement of the closure plates 300d, and the greater the height of the closure plates 300d, the greater the volume of the auxiliary fluid storage chamber.
The apertures 206 within the planar plates 204a, 204b, 204c, 204d are sized such that interior edges of the planar plates 204a, 204b, 204c, 204d extend above minimum fill levels in order to attenuate sloshing loads within the storage tank 12. The annular planar plates 204a, 204b, 204c, 204c can be used in the place of flexible membrane-type bulkheads. Alternatively, inner membranes with additional apertures (not shown) can be mounted within the existing apertures 206 of the planar plates 204a, 204b, 204c, 204d. By using ring-shaped planar plates 204a, 204b, 204c, 204d in place of the smaller-aperture-style planar plates 204 of previously described embodiments, the overall weight of the storage tank 12 can be further reduced.
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. These dimensions described are based on a few contemplated design cases and are given as non-limiting examples. It will be understood that other thicknesses, depending on the material used and application, may be used.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, 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.
This continuation-in-part application claims priority benefit to U.S. utility patent application Ser. No. 14/923,015 filed Oct. 26, 2015, which is a continuation-in-part application claiming priority benefit to U.S. utility patent application Ser. No. 14/506,909 filed Oct. 6, 2014, now U.S. Pat. No. 9,321,588 issued on Apr. 26, 2016, which claims priority benefit to U.S. utility patent application Ser. No. 13/681,764 filed Nov. 20, 2012, now U.S. Pat. No. 8,851,321 issued on Oct. 7, 2014, 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 U.S. utility patent application Ser. No. 12/823,719 filed Jun. 25, 2010, now U.S. Pat. No. 8,322,551 issued on Dec. 4, 2012, 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, abandoned, 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.
| Number | Date | Country | |
|---|---|---|---|
| 61562213 | Nov 2011 | US | |
| 60854593 | Oct 2006 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13681764 | Nov 2012 | US |
| Child | 14506909 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14923015 | Oct 2015 | US |
| Child | 15204387 | US | |
| Parent | 14506909 | Oct 2014 | US |
| Child | 14923015 | US | |
| Parent | 12823719 | Jun 2010 | US |
| Child | 13681764 | US | |
| Parent | 11923787 | Oct 2007 | US |
| Child | 12823719 | US |
