Abstract:
The invention relates to a stamped or braided form of a solid material or foil that can be inserted into a tank or container, for example to prevent an explosion of fuel inside the tank. Various combinations of materials can be used to produce the forms and braids. In a preferred embodiment, two or more stamped, helical forms of a metal foil material are interlocked or linked together, and a wire or fiber is placed at least partially in the center of one of the helical forms. This structure presents advantageous properties when used in fuel tanks, and resists deformation. In addition, certain forms or structures can be designed and used so they can be easily removed from the container or tank.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]     This application is a continuation of PCT application PCT/CH2005/000576, filed Oct. 4, 2005, which claims priority benefit of expired U.S. provisional application 60/615,026, filed Oct. 4, 2004, the entire contents of which are both incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to products that can be used in preventing explosions of fuel or other flammable or dangerous materials and/or products that be used in the clean-up or removal of explosive or dangerous materials and/or methods to use these products to prevent an explosion, as well as methods to produce these products. In a particular embodiment, the invention relates to a formed or braided product, typically but not necessarily made of or comprising aluminum or stainless steel, that can be inserted into a fuel tank to prevent the fuel from exploding. Advantageously, the optional shapes of the formed or braided products make them extremely easy to produce and easy to use in existing fuel tanks.  
       BACKGROUND OF THE INVENTION  
       [0003]     Many documents refer to materials for suppressing explosions or the spread of flames in a combustible product or fuel tank. The materials can be useful in a variety of situations. However, the widespread use of these materials has been hampered by the limitations in producing, transporting, and adding these materials to existing tanks. Furthermore, the form of these previous materials is typically a mesh or mesh-like structure, which is prone to being deformed or is to a significant degree inflexible. In one aspect, the invention addresses the problem of using these products by providing a new design for these materials and providing new methods to make and use them, especially when the use is in an existing fuel tank, such as fuel tanks for vehicles.  
       SUMMARY OF THE INVENTION  
       [0004]     In one aspect, the invention is directed to a method of producing a stable product that can be inserted into a fuel tank in order to prevent explosions. The product can be made of stainless steel, titanium, aluminum, aluminum alloy, magnesium alloy, or any metal, alloy, carbon, natural fiber, plastic or polymer that will not dissolve in a particular fuel or will not adversely effect the use of the liquid or fuel when it is in contact over a period of time. While examples for fuel tanks are mentioned throughout this disclosure, the materials and structures of the invention can also be used in other containers or liquid-transport vessels, such as with food products, milk, water, chemicals, industrial solutions, and the like.  
         [0005]     By way of example, one preferred method of making the formed materials employs stainless steel that is stamped or pressed into an elongated, polygonal form and optionally combined with a similar elongated polygonal form having a different polygon as its base shape. For example, a 5-sided helical form can be combined with a three or four-sided helical form. In addition, a separate line or fiber can optionally be placed to run through the center of one or more helical forms, where the line or fiber allows for easy removal of the material from a tank or vessel. In another example, one of the preferred methods employs an aluminum foil strip, where three or more strips of the foil are prepared and braided together to form a braided product. This braided product can be used as either a long braided chain, or used in smaller, cut and/or tied braids. The braided products function as other explosion suppressive or interior volume-space fillers. The products or materials of the invention may act by providing the appropriate flame quenching distance in a fuel suspension such that the chain reaction of a flame is prevented from branching into an explosive reaction. Many products and materials have been shown to prevent explosions when added to a fuel tank. The use of the formed or braided products of the invention, for example, allows metal or aluminum foil strips to be used in conjunction with a simple, small or handheld stamping, crimping or braiding device to directly add material to a tank or container. The device to stamp, crimp or braid metal or foil strips can be as simple as any rope-making machine or braiding machine.  
         [0006]     In another aspect, the invention allows the use of an aluminum foil or metal or alloy foil in such a way that the foil does not need to be stretched, held, flattened, or pressed to be prepared or manipulated into the shape to be placed in a tank. The braided shape of the invention does not require that the foil or metal be flattened or stretched. Thus, the production system is not limited.  
         [0007]     In one aspect, an object of the invention is a new way to prepare a filler, porous structure intended to prevent or retard explosive combustion in any tank. There are several ways to prepare these structures. A first consists of the use of strips that can be stamped to produce one or more helical structures with a polygonal form or polygonal cross-sectional form. For example, the stamping process produces a helical strip that completes a full turn in approximately 5 sides. However, a number of differently sided polygons can be used. As shown in  FIG. 2 , a 5-sided helical structure can be used. A cross sectional view of the helical structures is shown in  FIG. 1 , where a 5-sided polygonal structure is formed on the exterior, a 3-sided polygonal structure is in the interior, and at the center an optional line, wire, fiber, or strand of material. A single type of stamped strip can be used alone, where the strips can optionally be crossed over each other or linked to provide a non-uniform shape to the material. Also, combinations of two different types of helical structures can be used, as shown in  FIGS. 3, 6 ,  17 , and others. The stamping process can be replaced, or partially replaced, with a twisting and crimping process to produce similar materials and structures. A preferred strip is composed of stainless steel, but aluminum, carbon fiber, and other materials that are compatible with being placed in a fuel tank can be selected and used in combination.  
         [0008]     A second consists of a braided shape or structure, with three or more strands, but preferably four strands. Each strand can be of the same material or of two or more different materials, such as synthetic materials, metallic materials, or carbon or fibrous materials, or any other material compatible with a use in a fuel tank. In the case of metallic strand or strip of aluminum, aluminum alloy, magnesium alloy, copper alloy, titanium, and/or steel, these can be used in the form of a foil with an average thickness of approximately 0.05 mm, but other thicknesses can be selected and used. Each strand can be stamped and/or twisted to form a deformed structure as in  FIGS. 5-7  prior to being braided. The deformation process functions to provide an increase in the porosity of the resulting structure or braid that, by pressing or braiding, will generate a variety of volumes for the resulting braided products. In general, a multiplicity of sizes and shapes and the lack or a regular or fitted shape can be advantageous to the anti-explosive principles desired, however, it is not necessary.  
         [0009]     A third solution uses the same materials noted above but combines braiding and cutting. Advantageously, the invention differs from other manufacturing processes by using only the stamping and cutting step without having the need for complex machines to stretch previously cut sheets in order to guarantee the porosity of the material.  
         [0010]     The stamping or pressing allows one to realize a helical, rippled, twisted or irregular ribbon structure and also makes the strips able to receive one or several strands in a braid or weaved structure or form. The process characterizing the invention in one aspect allows a simple way to manufacture the product by using simple and well-known machines. According to the desired dimensions of the form or braid, it is even possible to produce it by a portable device that can be used to directly fill any reservoir. Also, the resulting form or braid can be cut into segments that will be themselves compressed to form spheres or polyhedrons, or used to constitute a more solid form according to the desired application. The use of strands or other ribbons or strips of metallic or synthetic materials associated with stainless steel or aluminum foil strands advantageously adds certain mechanical qualities to the resulting product, such as a resistance to being crushed and/or permanently deformed. In prior products, once the product is crushed within the tank the volume is permanently changed so that the anti-explosive qualities are reduced or even eliminated. The ability to use such a variety of braided and/or stamped structures while associating different materials together allows one to have access to a very wide range of applications, notably in the domain of chemical spill, nuclear waste, and other hazardous material removal or clean-up activities. The material according to the invention allows a reduction of fluid flow from any source by a “sponge” effect. This reduction of any leak, for example, can in certain cases be a major advantage in reducing and sealing a leak with a minimum of risk and pollution.  
         [0011]     In another aspect, the formed or braided material can be used temporarily inside a container or fuel tank, so that the material can trap undesirable particles or sludge material and reduce the spoiling of the container or tank or the contents. This can advantageously reduce or even eliminate the requirement to clean transport tanks that currently must be regularly emptied and cleaned. Thus, tanks in fuel transport vehicles can be easily cleaned by removing the contents of the formed material of the invention, which can be designed to collects particulate matter or other impurities by way of its composition or its coatings, or simply because of the large surface area it represents in the container. For example, aluminum containing materials will prevent the formation of biological contaminants know to reside in certain fuels. Similarly, liquid containing transport vehicles can be cleaned of biological material that may contaminate the tank or container and adhere to the formed or braided material of the invention because of the surface area presented by the structure or braids, or because of the composition or coating of the structures or braids. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  depicts a schematic of the cross-sectional view of a 5-sided polygonal stamped helical strip ( 1 ), with a 3-sided polygonal stamped helical strip ( 2 ), with an optional wire or fiber or line ( 3 ) in the center.  
         [0013]      FIG. 2  depicts a 5-sided helical strip where the exterior surface ( 4 ) and interior shaded surface ( 5 ) are shown.  
         [0014]      FIG. 3  depicts a 3-sided polygonal helical strip ( 7 ) inside a 5-sided polygonal helical strip ( 6 ).  
         [0015]      FIG. 4  depicts a 5-sided helical strip ( 8 ) on the exterior, a 3-sided helical strip ( 9 ) on the interior, and a center wire, fiber or line ( 10 ).  
         [0016]      FIG. 5  is a depiction of a braided form that is cut to a small size to accommodate the opening in a tank, and which is tied or crimped on each end so that a particular or desired volume is reached for each piece of the product. The size, shape, position of the tie or crimp, and material used in the product can be varied.  
         [0017]      FIG. 6  generally depicts a three-foil, braided helix pattern possible with the invention. Again, the type of foil or strip used is optional. The different shading of one twisted ribbon in  FIG. 6  represents the optional embodiment where one ribbon is of one material, while two ribbons are of another material.  
         [0018]      FIG. 7  depicts a more complex weaved structure or form possible under the invention. Again, the presence of different shading represent the option of using different material in the strips or ribbons. In this case, the ribbons or strips are of different shapes as well. The dark ribbon is a crimped or pressed shape while the four light ribbons are twisted. One or more of the ribbons or strips can also be essentially a tube or circular strand instead of a flattened ribbon.  
         [0019]      FIG. 8  depicts an embodiment where two of the strips or ribbons are essentially formed from one piece of foil or material. As shown, one piece of foil or one strip or ribbon is cut into two at one or more places along its length so that another ribbon or strip can be braided through. One of the forms used, in this and any other embodiment, can be a tubular shape or thread-like shape, whether hollow or not.  
         [0020]      FIG. 9  depicts a crimped ribbon or foil structure or form. This structure, as well as those in  FIGS. 10-13 , can be used with many other structures and forms and can be made or any appropriate material.  
         [0021]      FIG. 10  depicts a twisted ribbon form or structure.  
         [0022]      FIG. 11  depicts a crimped or partially folded structure or form.  
         [0023]      FIG. 12  depicts a cut ribbon or strip that can be used as two ribbons or strands in the braided forms or structures of the invention.  
         [0024]      FIG. 13  depicts another cut ribbon or strip that can be used as two ribbons or strands in the braided forms or structures of the invention.  
         [0025]      FIG. 14  is a photograph of crimped stainless steel embodiment of the metal strip of the invention. A single strip is cut, as with a high pressure water spray to avoid fragments and chaffing, and then crimped to produce an irregular structure.  FIG. 15  is a close-up view of the same structure in  FIG. 14 .  
         [0026]      FIG. 16  is a photograph of a multiple 5-sided polygonal helical structures folded or linked to each other. A desired length or combinations of lengths of these structures can be used and linked or folded with each other at one or multiple places along their lengths.  
         [0027]      FIG. 17  is a photograph multiple 5-sided polygonal helical structures braided or formed with each other. Again, a desired size or length of structures can be combined. Some of the helical structures can be stretched to essentially wrap around other structures at various parts. In effect, the multiple helical structures can be combined in a variety of ways to fill any number of tank sizes or vessels. 
     
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0028]     Each of the references (publication, article, web page, information source, or patent document, for example) referred to in this specification is hereby specifically incorporated herein by reference, in its entirety. Furthermore, each reference or any combination of references can be relied on and used, in whole or in part, to make, use, and test embodiments of the invention or specific examples described here. As this statement applies to each and every reference, document, or source of information, this specification will not repeat the incorporation by reference. This statement operates to effectively incorporate by reference in their entirety each and every reference (as defined above) listed or referred to in the specification.  
         [0029]     In making and using aspects and embodiments of this invention, one skilled in the art may employ conventional techniques. Exemplary techniques are explained fully in the literature and are well known in the art. For example, one may rely on general texts, web pages, and manuals to make and use the invention. The stamping, crimping, rope-making, and braiding machines and manuals of the art can be used, for example.  
         [0030]     Further, each of the following references or US patent documents are incorporated herein by reference and can be used to select a particular material for use in making the braided structures or forms of the invention or in applying the aspects of the invention to additional forms or concepts: U.S. Pat. No. 5,163,573; U.S. Pat. No. 6,415,942; U.S. Pat. No. 5,000,336; U.S. Pat. No. 6,751,835; U.S. Pat. No. 6,604,644; U.S. Pat. No. 4,764,408; Howell et al., Progress in Energy and Combustion Science, 1996, pp 22-121; Echigo, ASME/JSME Thermal Engineering Joint Conference, 1991, vol. 4, pp. xxi-xxxii; Coward and Jones, Limits of Flammability of Gases and Vapors, US Bureau of Mines Bulletin, 1952, No. 503; Jaronski et al., Lean Limit Flammability Study of Methane-Air Mixture, Archivum Combustinis, 1981, vol. 1, no. 3-4, pp. 203-215; and Blanc et al., Minimum Ignition Energies and Quenching Distances of Mixtures of Hydrocarbons and Ether with Oxygen and Inert Gases, Third Sympos. On Combustion Flame and Explosion Phenomena, 1949, pp. 363-367.  
         [0031]     In one embodiment, a helical geometry can be produced from a strip or ribbon of material by stamping, compression or lamination. Such helical structures are intended to fulfill the same functions as described above. A helical form or configuration may be produced from any metal or synthetic material furnished in foil or strip form and of varying thickness appropriate to a final use. Optional structures have three or more sides or surfaces but, ideally, have a five or eight sided helical structure.  
         [0032]     In one aspect, the structure lends itself to function as a spring or flexible or deformable material when a metal or firm ribbon is employed. The polygonal configuration results in rigidity able to withstand crushing from shock, compression, or violent deformation and promote the recovery of the material, whether partly or entirely, to its initial volume. This property gives the materials and strips of the invention significant advantages over previous products, typically a mesh structure, whose means of manufacture and constituents limit their commercial and technical utility.  
         [0033]     In the case of the helical form, components and manufacturing techniques offer advantages in simplifying the production as compared to previous products. For example, whether the product is made by stamping or bending, by means of mechanical, hydraulic or pneumatic force, little or no chaffing will be produced as occurs when metal is mechanically cut. Thus, the materials and strips of the invention are essentially free of particulate contaminants and requires little or no further treatment to uses. Also, the products of the invention will not degrade in any environment—in tanks, reservoirs, bottles or any other container—a factor of substantial importance in the event of the container being crushed when, normally, mechanical damage would produce fragments or particles that are undesirable inside the fuel or liquid. Since the form of this invention can be achieved with a pressure bending process, the risk of contamination by metal particulates is essentially or completely eliminated. The product can be made from a continuous strand or ribbon, so it has significant mechanical resistance in traction, its homogeneity is absolute, and it is resistant to tearing, cracking or otherwise degrading.  
         [0034]     Several different materials can be combined in a structure to enhance the performance or a particular function. Initially, a structure or braid will be produced after the manner set out. A helical structure allows multiple, smaller helical strands to be inserted within the spirals of one structure. These second or multiple strand may be fashioned of whatever material is deemed suitable, but preferably a material that is susceptible to the same stamping or pressure-forming methods as the larger helical strand. From such combinations of helical strands, the density of the product and almost any of its performance parameters can be modified, whether dynamic, physical or thermal. Only the size and number of polygonal helical structures limits the potential for optimized efficiency. Density itself, fundamental to the principle which in part governs this invention, can easily be adjusted, whether by compression of the pitch or diameter or the number of faces per spiral. This capacity to vary the strand or strands used to their purpose in a particular application is important to the flexibility of this product.  
         [0035]     As the drawings show (see  FIGS. 1 and 4 , for example), assembling two or more helical strands leaves the smallest in a core framed within at least three sides, appropriate to accommodate any fiber, wire, or line, although preferably a synthetic wire of any suitable configuration. Other than its natural, physical and mechanical capabilities, this helical structure will also serve to prevent or reduce combustion in a reservoir.  
         [0036]     A further advantage accruing from use of the polygonal helical forms is that the strand or spirals will not induce unintended mutual adhesion. The center line or strand can also act, particularly in tight bends and twists, against any unwinding of the helices. Another means to achieve the same effect would be to reverse the revolution of adjacent helices, preventing the likelihood of a strand collapsing or an unintended deformation or reconfiguration. Depending on the end use, the metallic or synthetic strand may be enlarged or reduced without adverse consequences to the invention properties and behavior.  
         [0037]     In one aspect, the aluminum foil for forming the strips can be an aluminum alloy and about 0.055 to about 0.2 mm in thickness, preferably about 0.055-0.05 mm, and 0.089-0.098 g/cm3 in density, and H 15-H 24 in hardness. However, aluminum of other thickness and hardness can be used.  
         [0038]     In another embodiment, stainless steel from conventionally available rolls can be used. Stainless steel and other metal rolls are available in many grades and include compositions of titanium, titanium alloys, nickel, and nickel alloys. The gauge or thickness desired can be selected depending on the desired weight and properties of the final product. Typically, a thickness of 0.0127 to about 3 mm can be selected. Textured metal rolls can be selected if the material is to be coated, for example, coated with anti-microbial or other products or agents. However, any of the materials than can be used, aluminum, metal, plastics, carbon fiber, composites, can be coated as well. Methods for coating materials consistent with their use in this invention are know in the art.  
         [0039]     As used herein, the term “ribbon” or “strip” is intended to encompass any type of material that can be stamped, braided or formed into the structures described here. Preferably, the strip or ribbon is a flat or flattened material that can be stamped, twisted, cut, or crimped and retain the stamped, cut, crimped, or twisted shape. Stainless steel, titanium and titanium alloys, and aluminum foil are preferred embodiments. A “braided” or “weaved” product is one that is composed or two or more strands that are connected in a manner that will substantially retain a certain three-dimensional shape. The braided or weaved shapes are evident in the Figures. The “structure” or “form” of the product refers to a product of the method of making an anti-explosion product of the invention, or a particular three-dimensional structure defined or depicted herein. The structure or form is independent of the material used to make it. However, a final product can be aluminum foil or a metalized foil.  
         [0040]     The examples given in the Figures are an illustration of preferred embodiments of the final product. The examples are not intended in any way to limit the scope of the invention, which is in part defined in the appended claims. As noted above, the final products can be produced as a long chain of braided ribbons or strands, or as cut braided forms. The products are designed to fit into the mouth of a conventional gas or fuel tank, such as approximately 2 cm to approximately 10 cm in diameter. The size of the ribbon or strip can vary in width and length. In certain examples, a 15 meter sample of a 5-sided helical structure of stainless steel, as shown in the figures, can be inserted easily into a 2 L bottle. The same material can be removed easily by simply pulling on one end. The amount of material to be inserted into a particular volume can vary depending on the intended use. For example, if there a desired to remove the material after it is inserted, what type of liquid or fuel will be used in the container, the weight of the material, the volume taken-up by the inserted material, and many other factors. In general, for an anti-explosion embodiment for a fuel tank, an aluminum or metal foil material can be inserted at about 0.4 square meters of total surface area per liter of volume.  
         [0041]     In a preferred embodiment, the braided form or structure is one that can retain its shape after being subjected to a compressive force. Thus, in a modern vehicle fuel tank, which can reform to substantially its initial shape after a collision, the product within the tank can substantially retain it shape and effectively retain its anti-explosive properties. This can occur whether or not the ribbons or strands are made of solid, hollow, twisted, crimped, or other materials or shapes, which are all optional. In a preferred method of making the anti-explosive products, a hand-held or portable device is used to produce the braided structure from available foil strips or ribbons, so that the anti-explosive product can be directly inserted into a fuel tank.