A variety of containers for various purposes are known. Many such containers must withstand pressure because the contents within the container are pressurized. One example application for such containers is to store gas for a variety of consumer, commercial, and industrial processes. Such gas storage containers typically must withstand relatively high pressures.
One attempt at configuring the containers to withstand high pressures includes using a spherical or cylindrical shape for the container. While those containers may be capable of withstanding relatively high pressures, they do not efficiently use space. By comparison to a rectangular prism-shaped container, a cylindrical container has a space use efficiency of about 78 percent and a spherical container has a space use efficiency of about 52 percent.
An illustrative example container includes a plurality of internal support members having a surface contour that at least approximates a minimum surface. The plurality of internal support members collectively provide structural support for carrying loads on the container. The plurality of internal support members collectively establish a plurality of cavities for at least temporarily containing fluid. An outer shell is connected with at least some of the internal support members. The outer shell includes a plurality of curved surfaces. The outer shell encloses the cavities.
In an example container having one or more features of the container of the previous paragraph, the surface contour of the support members directs forces along a direction, the outer shell curved surfaces have a surface profile, and the surface profile is situated so that the forces along the direction are distributed approximately equally along the curved surfaces.
In an example container having one or more features of the container of either of the previous paragraphs, interiors of the plurality of internal support members collectively establish at least one first cavity for at least temporarily containing fluid, exteriors of the plurality of internal support members collectively establish at least one second cavity for at least temporarily containing fluid, the outer shell curved surfaces include a plurality of first curved surfaces closing the first cavity, the outer shell curved surfaces include a plurality of second curved surfaces closing the second cavity, the first curved surfaces have a first surface profile, and the second curved surfaces have a second, different surface profile.
In an example container having one or more features of the container of any of the previous paragraphs, a portion of one of the first curved surfaces is connected to one of the interior support members at an interface, a portion of one of the second curved surfaces is connected to the one of the interior support members at the interface, and the first surface profile of the one of the first curved surfaces and the second surface profile of the one of the second curved surfaces are situated to substantially counteract a moment on the one of the first curved surfaces and the one of the second curved surfaces at the interface.
In an example container having one or more features of the container of any of the previous paragraphs, at least the first curved surfaces are substantially semi-spherical, and the first curved surfaces have a convex shape on an exterior of the container.
In an example container having one or more features of the container of any of the previous paragraphs, the second curved surfaces are substantially semi-spherical, and the second curved surfaces have a convex shape on an exterior of the container.
In an example container having one or more features of the container of any of the previous paragraphs, the interior support members respectively include connection interfaces configured to be connected to another interior support member or a portion of the outer shell, and the surface contour of the respective interior support members directs a load on the container in a direction generally perpendicular to the connection interface.
In an example container having one or more features of the container of any of the previous paragraphs, the connection interfaces are generally circular.
In an example container having one or more features of the container of any of the previous paragraphs, the outer shell defines a shape of the container, and the shape corresponds to a substantially rectangular prism.
In an example container having one or more features of the container of any of the previous paragraphs, the surface contour comprises a P surface.
An example container having one or more features of the container of any of the previous paragraphs includes a fluid within the container and the fluid is pressurized.
In an example container having one or more features of the container of any of the previous paragraphs, the container is configured as a heat exchanger.
In an example container having one or more features of the container of any of the previous paragraphs, the internal support members comprise metal, and the outer shell comprises metal.
In an example container having one or more features of the container of any of the previous paragraphs, the internal support members respectively comprise an interior surface and an exterior surface, the interior surface at least approximates a minimum surface, and the exterior surface at least approximates a minimum surface.
In an example container having one or more features of the container of any of the previous paragraphs, the outer shell comprises a plurality of corner members, a plurality of edge members situated between the corner members, and a plurality of face members; corresponding ones of the corner members, the edge members and the face members are secured together; and corresponding ones of the internal support members are secured to corresponding ones of the corner members, edge members or face members.
An illustrative example method of making a container includes forming a plurality of internal support members including establishing a surface contour of the internal support members, wherein the surface contour at least approximates a minimum surface. The plurality of internal support members are connected to establish a plurality of cavities for at least temporarily containing fluid. An outer shell having a plurality of curved surfaces is formed. The outer shell is connected with at least some of the internal support members to enclose the cavities. The internal support members collectively provide structural support for carrying loads on the container.
In an example method having one or more features of the method of the previous paragraph, forming the plurality of internal support members comprises: shaping a first sheet of material to establish the surface contour of at least one portion of at least some of the internal support members, shaping a second sheet of material to establish the surface contour of at least another portion of the sum of the internal support members, and connecting the shaped first sheet of material to the shaped second sheet of material.
In an example method having one or more features of the method of either of the previous paragraphs, shaping additional sheets of material establishes the surface contours of additional ones of the plurality of internal support members; and respective ones of the shaped additional sheets are connected together.
In an example method having one or more features of the method of any of the previous paragraphs, forming the outer shell comprises shaping a plurality of sheets of material respectively to establish the plurality of curved surfaces on each of the sheets.
In an example method having one or more features of the method of any of the previous paragraphs, the shaped sheets respectively include a plurality of openings among the curved surfaces, forming the outer shell includes obtaining a plurality of curved cap members having a shape and size corresponding to a shape and size of the openings, and respective ones of the curved cap members are connected to at least one of an internal support member situated adjacent one of the openings or a corresponding one of the shaped sheets along a periphery of one of the openings.
Various features and advantages of example disclosed embodiments will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
A container, such as the container 20, is configured to contain a pressurized fluid, such as a gas, liquid or gel. The container 20 includes the outer shell 22 and a plurality of internal support members that are configured to withstand the stress due to an internal pressure load without failing and with uniform displacement of the outer walls, similar to that of a cylinder or sphere under pressure. As can be appreciated from
In some embodiments, the container 20 contains a fluid for a prolonged period of time. In other embodiments, the container 20 is used for dynamically or only temporarily containing a fluid as it essentially passes through the container 20. It follows that the word “container” should not be construed in a particular manner that requires a static or long-term containment of a fluid.
The term “minimum surface” as used in this description refers to a minimum surface as known in mathematics. In some examples, the surface contour of the internal support members at least approximates a minimum surface. In other examples, the surface contour on the internal support members is exactly a minimum surface for at least a portion of the surface contour. In an example embodiment having internal support members 40 like that shown in
The face member 50 includes a connecting interface 52 that is configured to correspond to a connecting interface 46 on an internal support member 40, such as that shown in
In this example, the edge member 60 has an interior surface 66 with a surface contour that at least approximates a minimum surface along at least a portion of that surface contour. The edge member 60 includes the curved surface 26 on an exterior of the edge member 60.
Some example embodiments comprise a plurality of the internal support members 40, a plurality of the face members 50, a plurality of the edge members 60 and a plurality of the corner members 70. The connection interfaces are secured together using an appropriate technique based upon the material of the different members. For example, when the plurality of members comprise metal, a welding technique may be used for securing the interfaces together in a manner that provides a stable container that is able to withstand pressures of a pressurized fluid within the container in a leak-proof manner.
For discussion purposes, the forces are considered to originate at an intersecting point or location 90 between an internal support member surface 92 and outer shell surfaces 94 and 96. The partially spherical surfaces 94 and 96 of the outer shell experience moments at their edges due to the pressure load. The internal support member surface shown at 92 experiences pressure on both sides represented by the arrows 98. The pressure load causing the moment on the outer shell surfaces is schematically shown by the arrows 97. While the moment load in the curved beams or surfaces 94 and 96 are not completely eliminated, the effect on the structure and its stress is effectively minimized by balancing the loads on the three members or surfaces 92, 94 and 96. This arrangement reduces the moment in the wall so that the wall effectively behaves like that of a cylinder or sphere with a hoop stress. A cylinder wall under pressure has a maximum stress at the inner diameter, with a somewhat lower stress on the outer diameter of the wall. When one considers an isolated segment of the wall, this stress difference creates a moment. In the illustrated arrangement the inner wall 92, for example, with a zero net pressure, will experience a moment from its reaction force and the fact that it curved. Balancing such moment loads among the three surfaces 92, 94, 96 provides the ability for the external structure to behave like the curved external wall of a cylinder or sphere when subjected to internal pressure.
The stress in the outer shell adjacent to the intersection 90 is minimized by balancing the curvature of the surfaces 92, 94, and 96 along with the thickness of those walls, respectively, such that the magnitudes of the moments M0, M1, and M2 shown in
Each of the sheets 100 and 102 are shaped using a forming process, such as hot press forming, to establish a desired configuration, such as that shown in
At the stage of manufacture shown in
While
The welding techniques may be solid-state welding or fusion welding, depending on the materials selected for forming the different portions of the container. Solid state welding may include hot or cold pressure welding, friction stir pot welding, high frequency induction seam welding, advanced flash butt welding, projection spot welding or magnetically impelled arc butt welding processes.
Some examples may include a polymer or polymer matrix composite as the base material for the structure of the container. Such materials may include the advantage of lighter weight and an increased resistance to corrosion. One example includes sheet molding compound and using compression molding to fabricate the individual layers or pieces, which are then secured together using adhesive bonding. Fusion bonding may be used in embodiments that include thermoplastic matrix materials, such as PEEK and PEI. With fusion bonding, the polymer chains tend to inter-diffuse across the interface between pieces under heat and after cooling consolidation, the polymer chains are intertwined across the interface resulting in the bond line disappearing and an improved ability to transfer loads through the joint.
In embodiments that are intended to be used as a heat exchanger, a sheet metal forming technique as described above may provide economic advantages for forming titanium heat exchangers or using other alloy materials. With the illustrated example embodiments, composite materials having particular thermal properties may be selected to achieve desired heat exchange effects.
While not specifically illustrated, the container will include one or more openings for introducing a fluid into or removing a fluid from the container. A variety of closure mechanisms or valves may be incorporated to meet the needs of a particular situation. In a container such as that shown in the illustrations, different closure members may be used to control whether fluid enters or exits the two separate cavities within the container 20. One cavity includes a plurality of passages through the interiors of the connected internal support members 40. A second cavity includes passages along the outsides of the interconnected internal support members 40.
The different cavities and different fluid passages within a container such as the disclosed example embodiments makes the container useful for storing a single fluid or storing multiple fluids. Additionally, the container may be utilized as a heat exchanger between two fluids, with one of them being within the first cavity (e.g., within the internal support members 40) and the other fluid being in the other cavity within the container (e.g., on the outside of the internal support members 40).
In some embodiments, separate or isolated cavities exist within the container 20. In other embodiments, the internal support members 40 or the connections among them are configured to allow fluid to move from one cavity into the other, such as by including at least one hole in the wall of at least one of the internal support members. A plurality of cavities may be established within the container with those cavities being in fluid communication or isolated from each other depending on the needs of a particular situation.
Utilizing surfaces on the internal support members that at least approximate a minimal surface provides a uniform stress distribution along the structure of the container. In the illustrated examples, the connecting interfaces are generally circular, which provides even loading and the directions of the forces resulting from pressures inside the container tend to be in directions that are normal to the walls of the internal support members 40. With such an arrangement, little or no bending or shear tends to occur as the only load on the structure is a tension load.
The surfaces on the internal support members that at least approximate a minimum surface and the curved outer shell surfaces provide a container structure that is able to withstand internal pressures within the container with uniform displacement of the outer walls, because of the load balance provided by the surfaces and the arrangement of them, such as that schematically shown in
While various features and aspects of disclosed example embodiments are described above in connection with those particular embodiments, those features and aspects are not necessarily exclusive to the corresponding embodiment. The disclosed features and aspects may be combined in ways other than those specifically mentioned above. In other words, any feature of one embodiment may be included with or substituted for a feature of another embodiment.
The preceding description is illustrative rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of the contribution to the art provided by the disclosed examples. The scope of legal protection provided to the invention can only be determined by studying the following claims.
This invention was made with government support under Contract No. DE-AR0000254 awarded by the United States Department of Energy. The Government therefore has certain rights in this invention.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US2014/033949 | 4/14/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2015/160324 | 10/22/2015 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3663346 | Schoen | May 1972 | A |
3925941 | Pearce | Dec 1975 | A |
7156257 | de la Serna | Jan 2007 | B2 |
7866377 | Slaughter | Jan 2011 | B2 |
9234626 | Simmons | Jan 2016 | B2 |
20040173618 | Suzuki et al. | Sep 2004 | A1 |
20100276434 | Berger et al. | Nov 2010 | A1 |
20110056960 | Blanc et al. | Mar 2011 | A1 |
20150014323 | Loukus | Jan 2015 | A1 |
Number | Date | Country |
---|---|---|
1062671 | Sep 1979 | CA |
2013142178 | Sep 2013 | WO |
Entry |
---|
International Preliminary Report on Patentability for International application No. PCT/US20144/033949 dated Oct. 27, 2016. |
Fiona Meldrum's Group, Mechanical Properties of Bio-Inspired Materials, School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, 5 pages. |
Shin, et al., Finite Element Analysis of Schwarz P Surface Pore Geometries for Tissue-Engineered Scaffolds, Hindawi Publishing Corporation, Mathematical Problems in Engineering, vol. 2012, Artile ID 694194, 13 pages, doi:10.1155/2012/694194. |
International Search Report and Written Opinion of the International Searching Authority for International application No. PCT/US2014/033949 dated Sep. 3, 2014. |
Number | Date | Country | |
---|---|---|---|
20170030519 A1 | Feb 2017 | US |