Patent Publication Number: US-2012034482-A1

Title: Fire extinguishing material and fabrication method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Disclosure 
     The disclosure relates to fire extinguishing in general, and, specifically, to a fire-extinguishing composition carried on a flexible planar carrier and method of fabricating the same. 
     2. Description of the Related Art 
     Fire-extinguishing aerosols characterized by the presence of specifically formulated substances containing potassium nitrates and/or perchlorates as an oxidizer and supplier of the main fire-extinguishing agent, and binding fuels of plasticized and non-plasticized polymers, capable of transitioning to viscous or flexible state under the influence of thermal or/and mechanical nature have gained considerable attention in recent years. Among such binding fuels, phenol-formaldehyde and epoxy resins, polyvinyl butyral, cellulose ethers, and rubber are well known. 
     These aerosols, applied in a variety of environments, offer numerous advantages. In addition to superior extinguishing capabilities for open fire, the aerosols require no central system to operate, being independently deployable. Unlike sprinkler systems or foaming agents, the aerosols, having doused the flames, present no residual damage to furnishings, fixtures, or valuable mechanical and electronic assets. Further, compared to gas extinguishing methods, aerosols require no pressurized container and are significantly less costly. 
     The aerosols, in addition, provide the choice between remote deployment or automatic triggering in the environment. 
     Despite the stated advantages, however, some limitations remain. Aerosol producing fire extinguishing devices are traditionally contained in metal canisters or other bulky housings, with cooling agents, additional parts such as screens, spacers, and other parts, contributing significantly to the extinguishing device&#39;s overall size and weight. Canisters or other housings of the aerosol require not only requisite space for positioning, but more importantly, modification of the original design of the protected area to provide stable mounting hardware. In addition, the effective area of material deployment is relatively limited by the directional nature of the agent&#39;s dispersal. Hence, use of the aerosols in areas with limited space, strict limitations on design modification, or spaces presenting spacial abstractions, such as vehicle engine compartments or areas containing electrical and or/electronic equipment, may be impractical or impossible. 
     Thus, what is called for is a solution addressing the described limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawing, wherein: 
         FIG. 1  is a detailed cross section showing a portion of an exemplary fire extinguishing material as disclosed; 
         FIG. 2  is a detailed cross section showing a portion of another exemplary fire extinguishing material as disclosed; 
         FIG. 3  is a flowchart of a fabrication method for a fire extinguishing material as disclosed. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The disclosure provides a fire extinguishing material and a fabrication method thereof. 
     The fire extinguishing material as disclosed comprises a flexible planar carrier bearing at least an aerosol-producing fire extinguishing composition. The composition retains all the standard fire extinguishing capabilities known in the art to be exhibited by such compounds. 
     Constituent materials of the composition can include, but are not limited to, nitrates and/or perchlorates of the alkali metals, and cellulose with starch or iditol (phenol-formaldehyde resin). Numerous aerosol producing fire extingushing agents are applicable to the application as long as they constitute fuel (can also be binding fuel) and oxidizer (chemical compounds generating free oxygen when heated). Other constituents can be added to the composition to meet the needs of specific applications, such as cooling agents (dicyandiamide or melamine, for example), and combustion catalysts such as iron (III) or copper nitrates and additional fuel source such as coal powder or starch. 
     Effective protection is provided by a flexible planar carrier bearing the composition. 
     In a fire extinguishing material as disclosed, the carrier can be a hydrophilic flammable medium such as a textile of natural fibers such as cotton, paper, cardboard, or other material capable of absorbing the oxidizers and combusting. During deployment the carrier itself acts as an essential component of the aerosol producing composition as its fuel. 
     Alternatively, the carrier can be a planar matrix and the aerosol-producing fire extinguishing composition further comprises both fuel and oxygen generating components. In this embodiment, the carrier used provides a stable base for composition and serves as an integral structural component. The carrier in this embodiment may further exhibit thermal insulating properties, such as felt of silicon fibers, basalt wool, or any other fibrous mineral insulating material. If desired, the prepared material can serve as a thermal insulating agent for the environment of application. 
     The composition can be prepared as a solution, in which the carrier is immersed to achieve saturation, as a paste form, spread over the carrier, or as a spray to coat the carrier. The composition can further be manufactured in sheet form and fixed to the carrier by stapling, adhesive, stitching, or other means of attachment. As well, the composition can be mechanically worked into the structure of the carrier by pressing or other procedure. Finally, the composition can be prepared in any other form that allows even distribution of the aerosol producing agent over the surface of the carrier. 
     It should be noted that the flexible planar carrier prepared as disclosed can comprise bulk yardage lots of the desired carrier, or, alternatively, pieces precut and shaped according to the specific needs of the intended environment. 
     In addition, the carrier can further be coated on a side to be mounted to a surrounding surface by a thermal insulating layer, preventing the applied composition from loss of heat, and the mounting surface from permanent damage from the heat of combustive deployment. 
     As well, the finished carrier may further be applied with a hydrophobic layer applied at least on its active surface, thereby protecting the extinguishing composition from degrading moisture and physical impact. 
     The applied hydrophobic layer can further serve to modify or manage the ignition temperature of the applied composition. If the hydrophobic agent&#39;s combustion temperature is below that of the composition, such as if nitrocellulose lacquer is used, applied hydrophobic layer serves as an actual thermal fuse, igniting the composition at a temperature lower than it would otherwise. Alternatively, if the applied hydrophobic layer combustion temperature is higher than that of the composition, it elevates the temperature point at which the composition can ignite. The hydrophobic agent used need not necessarily be combustible as long as it is easily degradable by fire and/or high temperature, such as, for example, aluminum foil, in the case of which ambient temperature must reach 500° C., at which point the foil melts, exposing the aerosol producing composition for deployment. 
     It should be noted that the carrier can be folded on itself, thereby increasing the amount of aerosol deployed in a given area. 
       FIG. 1  is a detailed cross section showing a portion of an exemplary fire extinguishing material as disclosed, in which a single layer of carrier  10  is covered by a hydrophobic layer  11  applied on its active surface A, and a second hydrophobic layer  12  and a thermal insulating layer  13  on a side to be mounted B. 
       FIG. 2  is a detailed cross section showing a portion of another exemplary fire extinguishing material as disclosed, in which multiple layers of carrier  20  are covered by a hydrophobic layer  21  applied on its active surface AA, and a second hydrophobic layer  22  and a thermal insulating layer  23  on a side to be mounted BB. 
       FIG. 3  is a flowchart of a fabrication method for a fire extinguishing material as disclosed. 
     As shown, In Step  100 , a pre-measured amount of oxidizer is prepared, comprising, for example, potassium or sodium nitrates and/or perchlorates. Other constituents can be added to the composition to meet the needs of specific applications, such as cooling agents (ditsiandiamid or melemine, for example), constituting a Part 1 of the composition. 
     It is determined whether the carrier provides requisite combustibility. If so, Step  101  is implemented, and, if not, Step  102  is implemented, in which at least fuel components are added to the composition. The composition can be prepared as a solution, paste, spray, particulate, a planar sheet unit or other configuration suitable to the chosen carrier that allows even distribution of the aerosol producing agent over the area of the carrier. 
     In Step  101 , the composition is applied to the carrier, by saturation, spreading, spraying, mechanical infusion, fixing, or other method corresponding to the configuration of the composition and the chosen carrier. 
     It is determined whether a single layer of the carrier provides sufficient aerosol to the intended deployment area. If not, Step  103  is implemented, in which multiple layers of the treated carrier are stacked together, and, if so, it is determined whether thermal insulation between the material and the intended mounting surface is required. If so, Step  104  is implemented, in which a thermal insulating layer is applied to the mounting face of the treated carrier. Further, it is determined whether hydrophobic protection is required. If not, Step  106  is implemented, and, if so, Step  105  is implemented, in which a hydrophobic protection layer is applied to the active face of the treated carrier, or to both the active face and the mounting face of the treated carrier and Step  106  is implemented. 
     In Step  106 , the prepared material is readied for installation. 
     In use, the finished fire extinguishing material can be fixed to surfaces enclosing the area to be protected. Depending on the required coverage, a single application fixed to the top inner surface of the area, such as the inside of an engine hood or inside of the door of an electrical fuse or breaker box, may provide sufficient protection. Alternatively, additional application of the material to surrounding sidewall surfaces and even a floor, can be employed, for increased coverage. If the configuration of the elements to be protected is suitable, the carrier can even be wrapped around actual elements. 
     In keeping with the known behavior of such aerosol-producing fire extinguishing compositions, the extinguishing composition is deployed when it ignites and the aerosol is dispersed. Alternatively, a thermal fuse attached to any portion of the installed carrier can implement dispersal. Further, an electrical fuse attached to any portion of the installed carrier and controlled from a remote location can allow controlled dispersal of the aerosol. 
     The fire extinguishing material as disclosed, comprising a flexible planar carrier bearing an aerosol-producing fire extinguishing composition, provides workable application of the composition to be easily deployed along any planar surface, providing instant low-impact extinguishment of flames over a wide surface area in enclosed areas where deployment of other extinguisher types is unavailable. 
     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.