JP2002522715A - Hydrostatic pressure holding system - Google Patents

Abstract

(57) [Summary] A pressure vessel has a matrix structure extending in three dimensions. The matrix is generally under static mechanical (triaxial or three-dimensional) tension when carrying a load induced by the pressure of a compressed fluid stored within a series of interconnected voids at points of contact within the matrix. It is in. An outer cover that is impervious to fluid surrounds the matrix and is supported by and in contact with the matrix. The pressure vessel can have an irregular shape. A transfer means is provided which includes an arterial tract system for entering and draining the fluid. The solid surface component is attached to the matrix while in the liquid phase, and when the solid surface component changes to the solid phase, the component is secured to the matrix by an integral bond.

Description

DETAILED DESCRIPTION OF THE INVENTION

(Cross-Reference to Related Applications) This application was filed with the US Patent and Trademark Office on August 6, 1998, by Robert J. Setlock, Jr.
"Hydrostatic Pressure Maintenance System and High Strength Coupling Method"
Pressure Retainment System An High High Strength Bonding Method ””
Based on a provisional application entitled Serial Number 60 / 095,509.

TECHNICAL FIELD [0002] The present invention relates generally to the field of pressure vessels, and more particularly, to an apparatus and method for retaining pressurized liquid within a three-dimensionally structured matrix and coupling components to the matrix.

(Background Art) As a gas container under high pressure, it is generally necessary to use a hollow container having an outer wall of a sphere, a cylinder, an ellipsoid, an annular surface, or a composite shape of these shapes. These shapes are the most efficient shapes to withstand the tensile stresses induced in the wall by internal pressure, but are not the most efficient configurations possible. Also, these conventional shell shapes rarely fit the available space efficiency. There are many examples in the prior art where various configurations of internal supports are introduced inside the pressure vessel to facilitate the use of previously unused shapes. However, all previously unused pressure vessels in the prior art share the property of excessive weight. All such pressure vessels are heavier than comparable conventional pressure vessels due to inefficient use of structural materials. The present invention offers the new property of being lighter than an equivalent conventional pressure vessel made of the same material.

[0004] Another disadvantage of conventional containers is that the container can catastrophically break when structural damage to the wall occurs due to pressure-induced stress. An explosion occurs when the compressed gas and wall fragments are released suddenly, with serious consequences for nearby people and equipment.

[0005] The applicant has previously applied for a patent application No. WO97 / 27105, USSN0859
The specification of 2004 describes the possibility of providing a high-pressure storage tank for gas, in particular the possibility of providing a reinforcing matrix which is installed on the tank body and connected to its inner wall and occupies less than 50% of the internal volume of the tank. Have been. However, these high pressure storage tanks suffer from the disadvantage that they are difficult and expensive to manufacture and generally do not have sufficient strength to withstand the high pressures normally associated with such tanks.

The previously disclosed but not yet patented ERG Aerospace (ERG)
Aerospace's product specifies the use of its DUOCEL open-cell aluminum foam as an internal support inside an irregularly shaped pressure vessel, but this product is also difficult and expensive to manufacture, and It suffers from the disadvantage that it does not generally have sufficient strength to withstand the high pressures normally associated with such tanks.

[0007] Mannesmann AG has filed a patent application no. WO 98/33004 describes a compressed gas storage container in which an outer metal wall encloses a hollow chamber and in which a continuous-porous metal foam materially connected to the outer wall is provided. . However, such reinforced containers also generally cannot withstand the pressures normally associated with high pressure storage tanks.

Materials with uniform isotropic properties, such as steel, have equal mechanical properties (including tensile strength) in all directions (uniformly) in all directions (including tensile strength). Thus, steel can simultaneously withstand tensile loads in all three Cartesian coordinate axes. However, materials are rarely used in this way. Usually, the material is in one direction (axial load) or in two directions (plane load)
Loaded with. Some of the ability to support the load of the material remains unused, thus limiting structural efficiency. As the filament or fiber is pulled, it is in an axially loaded state. The ability to support the load in the other two directions of the material is not used. A conventional shell-type pressure vessel holding compressed gas is in a state where a planar load is applied. The material is stressed at any particular point on the wall in two directions defined by the plane tangent to the outer surface at that point, as shown in FIGS. The ability of the material to support loads in a direction perpendicular to that particular plane remains unused. Also,
Axial and planar loads cause angular distortion in the material, which primarily triggers structural failure.

It is advantageous to apply a load (hydrostatic, triaxial or three-dimensional load) evenly on the material in all three directions. The material under hydrostatic load (or triaxial or three-dimensional load) is fully utilized, and the capacity is fully utilized when further loaded. This ideal condition also means that there is no angular distortion or deformation. The absence of angular distortion leads to the further benefit that the yield strength at hydrostatic loading for the material is greatly increased. Therefore, the volume of the material required for manufacturing the container is reduced, and the weight can be reduced as compared with the conventional outer shell pressure container. Pressure vessels are an ideal application for structural hydrostatic tensile loads, as the fluid (liquid and / or gas) pressure to be counteracted is hydrostatic by definition.

[0010] Such a structure would take the form of an internal matrix having cavities or interstices for containing a pressurized fluid. The matrix is responsible for most of the pressure induced load. A lightly stressed thin, rigid outer cover is connected to the matrix to maintain fluid. The ability of each portion of the matrix material to carry a load in one axis (worst case) or in all three axes (best case) depends on the three-dimensional details (ie, texture) of the matrix.

One example of a matrix structure embodying the properties required to be the best case matrix is a material having a series of generally spherical voids (voids interconnected at their points of contact). Body. These contact points form an opening, and the size of the opening of the adjacent voids generally does not exceed 10%, preferably 5%, more preferably 2%, of the surface area of the voids, advantageously less than 1%. Such a matrix structure places a substantial amount of material in hydrostatic (triaxial or three-dimensional) tension. The plurality of voids are substantially spherical, and desirably have the same size.
Preferably, the voids are substantially uniformly distributed throughout the matrix and have a face-centered cubic orientation. FIG. 6 is an illustrative example showing a desired internal tissue having a uniformly distributed spherical void with very small passages 18 connecting each void to an adjacent void at each contact point. FIG. 7 shows a more desirable face-centered cubic orientation. Continuity is maintained in all three dimensions. This hydrostatically optimized tissue structure places a substantial portion of the matrix material under hydrostatic tensile loading when used as an internal matrix in a pressure vessel, making it virtually ideal. Demonstrate structural efficiency.

FIG. 8 is a photograph of a conventional foam. The support is an almost completely simple shaft member due to the irregular structure and lack of stoma walls. The tissue of such a structure does not efficiently support the hydrostatic tensile load of the matrix material when used as an internal matrix in a pressure vessel.

[0013] Relative density is the ratio of the volume of the matrix to the total volume of the matrix. In the best case of matrix texture, the strength of the matrix varies linearly with relative density. Therefore, the required density is the required hydrostatic tensile strength (with respect to the hydrostatic tensile strength of the base material (including the design factor)) (
(Maximum storage pressure). The face-centered cubic orientation results in about 67%, the maximum gas capacity that can be obtained for a uniform spherical void structure. This equates to a relative density of about 33%. Thus, the material preferably has a relative density of about 30% to about 35%, or about 2% to about 30%, or about 35% to about 50% (depending on the base material and packing method). .

Referring to FIGS. 1 and 2, a conventional shell-type spherical pressure vessel 10 will be described.
The volume of the base material required to manufacture the
Compared to the volume required to manufacture. These are approximate for thin-walled spheres.
It is a calculation. Maximum stress: σ₁ = Σ_Two = Pr / 2t Shell thickness: t = pr / 2σ Surface area: S = 4πr^Two  Material volume: V_smtl= St = 4πr^Two × pr / 2σ V_smtl= 2 × πpr^Three/ Σ (equation 60) where σ = maximum stress, base material p = maximum storage pressure r = pressure vessel radius t = shell thickness S = surface area V_smtl= Volume of shell material

For the matrix type spherical pressure vessel 12, the outer cover is not considered because it is not an important load-bearing structure. The volume of material required to form the matrix is the product of the sphere volume and the matrix density.

The volume of the sphere: V_sph= 4/3 x πr^Three  Therefore: V_mmtl= 4/3 x πr^Three × p / σ = 1.33 × πpr^Three/ Σ (Equation 62) where V_sph= Sphere volume V_mmtl= Volume of matrix material

A comparison of equations 60 and 62 reveals material efficiency advantages. An optimal matrix structure theoretically results in a 33% improvement for a spherical shell. Practical use cases show that an improvement of 20% or more is achieved.

Referring now to FIGS. 3 and 4, a conventional shell-type cylindrical pressure vessel 1 will be described.
The volume of the base material necessary for producing the cylindrical pressure vessel 4 is a matrix type cylindrical pressure vessel 1
6 compared to the volume required to make 6. These are estimates for thin walled cylinders and do not consider end plugging. The hoop stress σ ₁ is twice the longitudinal stress σ ₂ in all outer shell cylinders.

The maximum _{stress: σ max = σ 1 = pr} / t shell thickness: t = pr / σ surface area: S = 2πrl material _{volume: V smtl = St = 2πrl ×} pr / σ V smtl = 2 × πpr 2 l / Σ (Equation 66) where l = length of cylinder

Regarding the matrix type cylindrical pressure vessel 16, the outer cover is not considered because it is not an important load-bearing structure. The volume of material required to form the matrix is the product of the volume of the cylinder and the matrix density.

The cylinder volume: V _cyl = πr ² l ^{_{Therefore: V mmtl = πr 2 l ×}} p / σ = πpr 2 l / σ ( equation 68)
Where V _cyl = volume of cylinder

A comparison of equations 66 and 68 reveals a material efficiency advantage. An optimal matrix structure theoretically results in a 50% improvement for a cylindrical shell. Practical use cases show that an improvement of 40% or more is achieved.

[0023] The relatively thin and light outer cover may be connected to the matrix or formed as one piece with the matrix. For analytical purposes,
The thin outer cover may be configured as a number of small, interconnected, substantially circular plates. There will be multiple circles with significantly different radii. The maximum radius size of these circles is determined by the size of the matrix gap. FIG. 5 shows a polygon with the radius of the inscribed circle = a and the number of sides = n. The required thickness of the outer cover is a function of the fluid pressure, the allowable material stress, and the radius size of the polygon. The maximum stress in the polygonal plates is applied to the outer edge of each plate according to Roark's formula for stress and stress deformation. The following data is from No. 2 in Table 26 in Roark's Formula. Taken from 20.

[0024]

[Table 1]

Maximum stress: σ_max= -Β_Twoqa^Two/ T^Two  Thickness: t^Two = | -Β_Twoqa^Two/ Σ_max| t = √ | -β_Twoqa^Two/ Σ_max| (Equation 72) where σ_max= Maximum allowable stress β_Two= Factor from table a = Radius of polygon q = Fluid pressure t = Film thickness

According to one embodiment, the efficiency of a matrix type pressure vessel is illustrated. A circular polygon with the number of sides = ∞ and radius = matrix void radius is β ₂
Value = 0.75, used as worst case condition. Assuming a hydrostatically optimized matrix made of 6061T6 aluminum with a yield stress of 40 kilopounds per square inch (psi) and a void size of 0.0625 inch radius, the thickness obtained from equation 72 is Tables below are for q = 450 pounds / square inch, 6 kilopounds / square inch and 15 kilopounds / square inch.

[0027]

[Table 2]

Components having a solid surface, such as an outer cover, a fill nozzle, etc., may be formed integrally with the matrix or connected later.

DISCLOSURE OF THE INVENTION According to the present invention, there is provided a hydrostatic pressure holding device for a compressed fluid capable of withstanding a high internal pressure. The pressure holding device includes a matrix that carries the load induced by the pressure of the compressed fluid. The matrix structure comprises a body of material having a series of generally spherical voids communicating with each other at points of contact. These contact points form an opening, and the size of the opening of the adjacent voids generally does not exceed 10%, preferably 5%, more preferably 2%, of the surface area of the voids, advantageously less than 1%. Such a matrix structure can be described as a matrix structure in which a substantial amount of material is placed in hydrostatic (triaxial or three-dimensional) tension by providing a substantially closed continuous void structure. it can. The plurality of voids are substantially spherical, and desirably have the same size. Preferably, the voids are substantially uniformly distributed throughout the matrix and have a face-centered cubic orientation.

The matrix is desirably a metal, for example, aluminum, steel, stainless steel, or the like.

An outer cover surrounds the matrix and holds the compressed fluid inside the matrix. The outer cover has an inner surface connected to an outer boundary or outer boundary area of the matrix. Retained fluid cannot penetrate the outer cover. The outer cover is supported in substantial contact over the outer boundary surface of the matrix.

[0032] Transport means are provided for admitting fluid into and out of the matrix.

A hydrostatic device with a nearly closed void structure is generally not achieved by standard metal (or other) foam manufacturing techniques. This type of device can be constructed by using investment casting techniques that use small, uniform, spherical balls. For example, a metal shaped outer skin similar to or compatible with the inner matrix to be formed is provided, and the inner matrix is coated by coating beads of a volatile substance such as carbamide with a powdered metal. By forming and adding these beads to a container, finishing with a layer of powdered metal and making the system accessible by a manifold or tube, a gas containing structure can be manufactured. Thereafter, when the unit is heated at about 200 ° C., the metal slurries stick together and the carbamide beads volatilize and escape through the manifold. This "semi-finished" container can then be sintered in a higher temperature furnace to provide the final structure. Internally, due to the manufacturing method described above, the pores are all spherical and the interconnects at the points of contact with adjacent pores are small, and thus a porous structure with only small interconnects between each pore Is produced, so that the overall strength of the matrix is maximized.

While adding organic spheres to the canister is best achieved by a “snowstorm” packing method to minimize irregularities in the structure, simple single-sized pore structures are It only empties 67% of the volume as free space. This volume can be increased by using smaller sized spheres that efficiently fit the space between other spheres.

Experimental work has demonstrated that this is optimal when the diameter ratio is between 7: 1 and 10: 1 and the proportion of small spheres is between 18 and 20%. Again, by using the "Snowstorm" packing technique, and by using the required size range and sphere percentage, the structure can be made very uniform.

In another embodiment, a powdered metal skin that avoids any shrinkage problems may be used.

The space of the spherical voids oriented in the face-centered cubic structure has a radius ratio of d _small = d _large (√2-1) (d _small is the diameter of the smaller void, and d _large is the larger of the larger void. Even smaller gaps (diameter of gap) may be accommodated. Such steps may be repeated with smaller spherical voids (resulting in a lower density configuration). Another manufacturing method is
No. 5,151,246, filed by Fraunhofer-Gesellschaft, which is hereby incorporated by reference. Including but not limited to metal foam forming methods. Such a method may be modified to a rapid prototype technique or the like to achieve the structure required for the present invention.

The invention will be more completely understood and further features and advantages will be apparent in the following detailed description of preferred embodiments thereof, as illustrated in the accompanying drawings.

Referring now to FIGS. 6, 7, 9 and 10, a hydrostatic pressure holding device for storing compressed fluid is shown at 20. This device, which is lighter than an equivalent conventional pressure vessel made of the same material, includes a three-dimensional matrix 22 that carries the pressure induced load of a compressed fluid (not shown). The matrix can be made of various materials and structural configurations. Polymers, metals and composites thereof can be utilized to form a hydrostatically optimized tissue matrix. FIG.
Is an illustrative example of a hydrostatically optimized tissue having a face-centered cubic orientation of spherical voids, which is a preferred structure for embodying the present invention. The individual pores are substantially spherical and are distributed almost uniformly throughout the matrix structure. Each pore 26 (which shows a nearly closed pore structure) has a continuous wall 28 that almost completely contains a space or gap 30 containing the compressed fluid. Gap 30
Communicate with one another via relatively small openings or holes 32 in the cell wall 28.
The holes 32 ensure a substantially uniform distribution of the fluid throughout the matrix 22. The limits of the outer dimensions of the matrix 22 define the outer interface 34.

Due to the three-dimensional nature of the hydrostatically optimized tissue 24, substantially all portions of the matrix 22 are substantially in hydrostatic tension when carrying pressure-induced loads. . The matrix 22 is preferably about 30% to about 35%,
Alternatively, it has a relative density of about 2% to about 30%, or about 35% to about 50% (depending on the base material and packing method). However, the novel feature of being lighter than conventional pressure vessels is independent of relative density. The lighter weight feature is entirely due to the structural efficiency of the matrix organization.

An outer cover 36 surrounds the matrix 22 and holds the compressed fluid inside the matrix 22. Fluid cannot penetrate the outer cover. Outer cover 36 has an outer surface 38 and an opposite inner surface 40. The outer cover inner surface 40 is connected to the outer boundary surface 34 of the matrix. The outer cover 36 is connected to the outer boundary 3 of the matrix.
4 and supported substantially in contact therewith. The outer boundary surface 34, and thus the outer cover 36, may be considered to take any imaginable shape. This is because the majority of the stress is carried by the matrix and very little by the outer cover 36, so hoop stress is no longer the limiting factor. Therefore, the configuration of the outer boundary surface 34 may be symmetric or a shape with a reduced degree of symmetry (asymmetric shape).

The matrix 22 and the outer cover 36 of the hydrostatic pressure holding device 20 have the same total volume (measured with respect to the outer surface 38 of the outer cover 36), are made of the same base material, and have the same design factor. Have a total structural weight significantly less than that of an equivalent conventional shell-type pressure vessel designed to withstand the same fluid pressure.

Transfer means are provided for entering fluid into and out of the matrix 22. Specifically, the transfer means includes at least one nozzle 42 connected to the outer cover 36. The nozzle 42 has an inner surface 44 and an orifice 46 and communicates with the matrix gap 30 through the orifice 46. If desired, a network of arterial tracts 48 may be provided that communicate with the nozzle orifices 46 and the matrix gap 30. FIG. 9 shows a cross-sectional view of the arterial tract system 48. The arterial tract 48 includes a tube 50 that becomes smaller and more numerous as it progresses from the nozzle orifice 46 into the matrix gap 30. Tube 50 includes a plurality of holes 52 for carrying fluid, as shown in FIG. The arterial tract 48 increases the flow rate of the fluid throughout the system so that fluid enters the matrix 22 more quickly as fluid enters, and fluid is collected from the matrix 22 more quickly as fluid exits. Arterial tract 48 and matrix 22 may be fabricated as one integral structure or separately. The arterial tract 48 may be made of the same material as the matrix 22 or of a different material that can be shared with and connect to the matrix 22 structure.

If the solid outer cover 36 is not present as an integral part of the matrix, the novel connection system shown in FIG. Used to attach integrally to outer boundary surface 34. The outer cover 36 or component 54 is built into the solid phase matrix 22 while the inner surface of the component or the entire component 54 is in a liquid phase. The inner surface of the component is allowed to penetrate or extend a predetermined distance 56 into the matrix 22. Then the components solidify,
The components are fixed to the matrix 22. This results in an integral strong coupling structure. This cheap connection can also be used for irregular outer boundary configurations. Methods of application include, but are not limited to, potting, dipping, spraying, brushing, vacuum dipping, and the like. The outer cover may be thick enough to provide mechanical protection from impact, penetration and the like. A label may be introduced to provide information on type confirmation, safety instructions, and the like. The cover may have decorative features and some systems may use biocompatible materials.

The hydrostatic hold method is described with respect to the storage of compressed fluid. This method
Spreading the matrix structure 22 to the outer boundary surface 34 in three dimensions, surrounding the matrix 22 with a fluid impervious outer cover 36, outer cover 36
Connecting the inner surface 40 to the outer boundary surface 34 of the matrix 22, supporting the outer cover 36 in substantial contact with the outer boundary surface 34 of the matrix, and placing the fluid under pressure into the matrix 22. Retaining the compressed fluid in the gap 30 within the matrix 22, retaining the compressed fluid within the matrix 22 with the outer cover 36, substantially compressing the compressed fluid into the matrix 22 material by the pressure of the compressed fluid. Inducing a hydrostatic load on substantially all portions of the matrix 22 material under substantially hydrostatic tension, and evacuating fluid from the matrix 22.

Connecting the nozzle 42 to the outer cover 36;
6 further comprising the step of communicating 6 with the gap 30 of the matrix via the nozzle 42.

In addition, the steps of communicating the network of arterial tracts 48 with the nozzle orifices 46 and the gaps 30 in the matrix, distributing the fluid to the matrix 22 through the arterial tracts 48 when entering the fluid, and Further collecting fluid from the matrix 22 via the arterial tract 48.

In addition, the step of juxtaposing the inner surface of the component with the outer boundary surface 34 of the matrix 22 while the material of the inner surface is in the liquid phase, infiltrating the inner surface material into the gap 30 of the matrix to a predetermined depth. The step further includes the step of changing the inner surface material to a solid phase, thereby securing the components to the matrix 22.

Separately, forming an outer boundary surface in an irregular configuration.

Still further, forming a matrix 22 and forming the matrix by using an investment casting process.

Still further, forming the matrix 22 includes forming the matrix from a Fraunhofer type metal foam that has been modified to drill small holes in adjacent voids.

Still further, forming a matrix 22 includes forming the matrix by using a rapid prototype process.

As will be appreciated from the above description, the present invention satisfies the need to provide a system for holding pressurized fluid, which system does not induce planar loading on relatively thick walls and has less The use of more efficient hydrostatic loads in the material significantly reduces weight, and the system is not limited to spheres, cylinders, ellipsoids or toroids, but has a reduced degree of symmetry. So that it fits inside any given envelope body, the system does not explode in the event of structural structural failure of the wall, and the system is a solid surface component in a matrix of any surface configuration Including a method to securely connect.

Although the invention has been described and illustrated in a preferred embodiment, those skilled in the art will make modifications that are deemed functionally equivalent to the invention. For example,
The hydrostatic pressure holding device described above and shown in FIG. 9 is a rectangular parallelepiped. It should be understood that any shape or configuration may be utilized, whether symmetric or asymmetric. Therefore, it is to be understood that the above detailed description of the embodiments of the present invention has been provided by way of example only. Various details regarding design and manufacture may be modified without departing from the spirit and scope of the invention, which is set forth in the following claims.

[Brief description of the drawings]

FIG. 1 is a front view of a spherical shell type pressure vessel, showing a plane stress applied to a shell.

FIG. 2 is a front view of a matrix-type spherical pressure vessel, showing a matrix without an outer cover.

FIG. 3 is a front view of a cylindrical shell-type pressure vessel whose end is not closed, showing a plane stress applied to the shell.

FIG. 4 is a front view of a matrix type cylindrical pressure vessel, showing a matrix without an outer cover.

FIG. 5 is a polygon having an inscribed circle with radius = a and number of sides = n.

FIG. 6 is a diagrammatic illustration of a hydrostatically optimized tissue showing a uniformly distributed spherical void with very small passages connecting each void to an adjacent void at each contact point. is there.

FIG. 7 is an illustrative example of a hydrostatically optimized tissue, illustrating a desired face-centered cubic orientation of a spherical void.

FIG. 8 is a photograph of a conventional foam.

FIG. 9 is a partial sectional isometric view of a hydrostatic pressure holding device according to the present invention.

10 is an enlarged view of detail 12 of FIG. 10, showing a cross section of the arterial tract.

FIG. 11 is a cross-sectional view of the matrix and the solid surface component, showing the penetration of the component material into the matrix.

[Explanation of symbols]

 Reference Signs List 20 hydrostatic pressure holding device 22 matrix 24 tissue 26 stomata 28 cell wall 30 gap 32 hole 34 outer boundary surface 36 outer cover 38 outer surface 40 outer cover inner surface 42 nozzle 44 inner surface 46 nozzle orifice 48 arterial path 50 tube 52 hole 54 component 56 predetermined distance

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AL, AM, AT, AU, AZ, BA, BB, BG , BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, GM, HR, HU, ID, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, R , RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, UZ, VN, YU, ZW (72) Inventor Robert Joseph Sellock Jr. Gilky Ridge Road 42920 (72) Inventor Michael Ernest Garrett GU 22 Surrey, Surrey, United Kingdom 7 7X Woking York Road 92 Gables F-Term (Reference) 3E072 BA01

Claims (34)

[Claims] A pressure holding device includes a matrix that carries a pressure induced load of a compressed fluid, the structure of the matrix defining a series of substantially spherical voids interconnected at points of contact. A pressure holding device, comprising a body of material having a contact, said contact points forming a small opening, and wherein the size of said opening between adjacent voids does not exceed about 10% of the internal surface area of said void. . 2. The apparatus of claim 1 wherein said matrix structure is substantially spherical in shape and includes voids distributed substantially uniformly throughout said matrix. 3. The apparatus of claim 1, wherein said matrix structure includes similarly sized voids. 4. The apparatus of claim 1, wherein said matrix structure includes voids in a face-centered cubic orientation. 5. The apparatus of claim 1, wherein in the matrix, a substantial amount of the material is under a tension selected from hydrostatic tension, triaxial tension, three-dimensional tension, or a combination thereof. . 6. The apparatus of claim 1, wherein the size of the opening between the adjacent voids does not exceed about 5% of the internal surface area of the void. 7. The apparatus of claim 1, wherein the size of the opening between the adjacent voids does not exceed about 2% of the internal surface area of the void. 8. The apparatus of claim 1, wherein the size of the opening between the adjacent voids does not exceed about 1% of the internal surface area of the void. 9. An outer cover surrounds a matrix and retains the compressed fluid within the matrix, the outer cover having an inner surface connected to an outer boundary surface of the matrix, wherein the fluid covers the outer cover. The apparatus of claim 1, wherein the outer cover is impervious to air and the outer cover is supported in substantial contact over an outer boundary of the matrix. 10. The apparatus of claim 1, further comprising transfer means for admitting said fluid into said matrix and discharging said fluid from said matrix. 11. The device of claim 1, wherein the device stores compressed fluid. 12. The transfer means further includes at least one nozzle connected to the outer cover, the nozzle having an inner surface, the nozzle having an orifice, and a gap in the matrix through the orifice. The pressure holding device according to claim 1, which is in communication. 13. The gap between the nozzle orifice and the matrix for distributing the fluid to the matrix when the fluid is admitted and for collecting the fluid from the matrix when the fluid is ejected. 3. The pressure holding device of claim 2, further comprising a network of communicating arterial tracts. 14. The pressure holding device according to claim 1, wherein the inner surface extends within the matrix by a predetermined distance, and the inner surface is fixed to the matrix. 15. The pressure holding device according to claim 1, wherein said outer boundary surface configuration is irregular. 16. The pressure holding device according to claim 1, wherein said matrix comprises a structural foam. 17. The pressure holding device according to claim 6, wherein the matrix is a Fraunhofer type metal foam. 18. A hydrostatic pressure holding device for storing a compressed fluid, said pressure holding device comprising: (a) a matrix bearing a load induced by the pressure of the compressed fluid; Have a series of voids throughout which extend in three dimensions, interconnect at the point of contact and contain the compressed fluid, the voids communicating to distribute the stream substantially uniformly; A matrix wherein substantially all of the matrix is under substantially hydrostatic tension when carrying the pressure induced load; and (b) surrounding the matrix with the compressed fluid within the matrix. An outer cover for retaining, having an outer surface and an inner surface opposite the outer surface, the inner surface of the outer cover being connected to an outer boundary surface of the matrix, wherein the fluid cannot penetrate the outer cover; Comprises: an outer cover supported substantially in contact with an outer boundary surface of the matrix; and (c) transfer means for entering the fluid into the matrix and discharging the fluid from the matrix. (D) the matrix and the outer cover of the hydrostatic pressure holding device have the same total volume measured with respect to the outer surface of the outer cover, are made of the same matrix, and have the same design factor and the same A hydrostatic pressure storage device for storing compressed fluid having a total structural weight that is less than the total structural weight of an equivalent conventional shell-type pressure vessel designed to withstand fluid pressure. 19. The transfer means includes at least one nozzle connected to the outer cover, the nozzle having an inner surface, the nozzle having an orifice, and communicating with the gap in the matrix via the orifice. 19. The pressure holding device according to claim 18, wherein 20. A method for distributing said fluid to said matrix upon entry of said fluid and collecting said fluid from said matrix upon discharge of said fluid,
20. The pressure holding device of claim 19, further comprising a network of arterial tracts communicating with the nozzle orifices and gaps in the matrix. 21. The pressure holding device according to claim 18, wherein the inner surface extends within the matrix by a predetermined distance, and the inner surface is fixed to the matrix. 22. The pressure holding device of claim 18, wherein said outer boundary surface configuration is irregular. 23. The pressure holding device according to claim 18, wherein said matrix comprises a structural foam. 24. The pressure holding device according to claim 23, wherein the matrix is a Fraunhofer type metal foam. 25. A method for maintaining a hydrostatic pressure for storing a compressed fluid, comprising: (a) spreading the matrix structure to an outer boundary surface in three dimensions; and (b) impregnating the fluid. Enclosing the matrix with an outer cover; (c) connecting the inner surface of the outer cover to the outer boundary of the matrix; (d) substantially placing the outer cover above the outer boundary of the matrix. (E) placing the fluid under pressure into the matrix; and (f) a series of interconnected voids at the point of contact within the matrix within the matrix. (G) retaining the compressed fluid within the matrix with the outer cover; and (h) pressure of the compressed fluid. Inducing a load within the matrix; (i) carrying the load under substantially hydrostatic tension in substantially all of the matrix; and (j) discharging the fluid from the matrix. A method for maintaining a hydrostatic pressure for storing a compressed fluid. 26. The method of claim 24, further comprising the steps of: (a) connecting a nozzle to the outer cover; and (b) communicating an orifice with a gap in the matrix via the nozzle. 27. (a) communicating a network of arterial tracts with the nozzle orifice and the interstices of the matrix; and (b) distributing the fluid through the arterial tract to the matrix upon entry of the fluid. 27. The method of claim 26, further comprising the step of: (c) collecting the fluid from the matrix via the arterial tract when draining the fluid. 28. (a) juxtaposing an inner surface of a component with the outer boundary surface of the matrix while the material of the inner surface is in a liquid phase; and (b) interposing the inner surface in a gap in the matrix. 26. The method of claim 25, further comprising the steps of: penetrating a material to a predetermined depth; and (c) converting the inner surface material to a solid phase, thereby securing the component to the matrix. 29. The method according to claim 25, further comprising the step of forming the outer boundary surface with an irregular configuration. 30. The method of claim 25, further comprising forming the matrix from a structural foam. 31. The method of claim 30, further comprising forming the matrix from a Fraunhofer type metal foam. 32. A hydrostatic pressure holding device for storing a compressed fluid, said pressure holding device comprising: (a) a matrix bearing a load induced by the pressure of the compressed fluid; Extending in three dimensions and having a gap for containing the compressed fluid, wherein substantially all of the matrix is under substantially hydrostatic tension when carrying the pressure-induced load. A matrix, and (b) an outer cover surrounding the matrix and retaining the compressed fluid within the matrix, the inner cover being connected to an outer boundary surface of the matrix, wherein the fluid penetrates the outer cover. The outer cover, wherein the outer cover is supported substantially in contact with an outer boundary surface of the matrix; and (c) placing the fluid into the matrix. And a transfer means for discharging the fluid from the matrix. 33. A method for filling a pressure vessel incorporating a hydrostatic pressure holding device with a fluid under pressure, comprising: (a) obtaining a pressure vessel incorporating a hydrostatic pressure retaining device. Wherein the hydrostatic pressure holding device comprises: (i) a pressure vessel having a filling opening and a tank body, the tank body having at least two opposed inner walls defining an internal volume; and (ii) the tank A reinforcing matrix disposed on the body and connected to the inner wall, wherein the reinforcing matrix structure includes a body of material having a series of generally spherical voids interconnected at contact points, the contact points defining openings. Obtaining a pressure vessel incorporating a hydrostatic pressure holding device, the reinforcement vessel having a reinforcing matrix formed and having a size of an opening of an adjacent void not exceeding about 5% of the inner surface area of the void; and (b) said pressure vessel. The pressure The method comprising at least partially filled with said fluid. 34. A method of filling a pressure vessel incorporating a hydrostatic pressure holding device with a fluid under pressure, comprising: (a) obtaining a pressure vessel incorporating a hydrostatic pressure retaining device. Wherein the hydrostatic pressure holding device comprises: (i) a pressure vessel having a filling opening and a tank body, the tank body having at least two opposed inner walls defining an internal volume; and (ii) the tank A reinforcing matrix disposed on the body and connected to the inner wall, wherein the reinforcing matrix structure includes a body of material having a series of generally spherical voids interconnected at contact points, the contact points defining openings. Obtaining a pressure vessel incorporating a hydrostatic pressure holding device, the reinforcement vessel having a reinforcing matrix formed and having a size of an opening of an adjacent void not exceeding about 5% of the inner surface area of the void; and (b) said pressure vessel. Pressure inside The method comprising placing the fluid below, that allows the (c) said fluid under pressure remains the pressure vessel.