Abstract:
A flame resistant packaging system has an outer box and a flame and heat resistant liner inside the box. The liner is constructed of a layer of a ceramic fiber and a layer of metal foil. The edges of the liner are joined at a seam, forming a compartment for holding an article to be packaged. The foil layer of the liner faces the inside of the compartment. A patch, similarly constructed of foil and ceramic fiber, is attached over the seam to prevent hot gasses from entering the compartment at the seam. The compartment is substantially closed by folding the sides of the liner inward. End inserts, similarly constructed of foil and ceramic fiber, are inserted into the compartment to substantially cover the areas where the liner is folded to close the compartment.

Description:
CLAIM FOR PRIORITY 
       [0001]    This application claims the priority of U.S. Provisional Application Ser. No. 61/411,194, filed Nov. 8, 2010, entitled “Flame And Heat Resistant Packaging System And Method Of Making Same,” which application is incorporated by reference into the present application. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    This disclosure relates to packaging resistant to flame penetration, particularly packaging for shipping containers of oxidizing material. 
         [0004]    2. Background 
         [0005]    An example of packaging requiring resistance to flame penetration are the chemical oxygen generators used in the aviation industry, and commonly shipped in the cargo hold of an aircraft. The reader should note, however, that this disclosure is not limited to the protection of chemical oxygen generators, but is applicable to the enclosure of other types of gas containers, gas generators, explosives, or any container having chemical contents that may react under flames. 
         [0006]    Various safety precautions are taken to prevent actuation of oxygen generators and similar devices during shipment. These precautions include enclosure of the chemical oxygen generator in a primary package that reduces the possibility of mechanical actuation. However, a fire in the cargo hold of an aircraft could raise the temperature of such a chemical oxygen generator enough to cause actuation of the generator, or cause actuation by flame penetration of the packaging to the generator. The present subject matter provides outer packaging, and a method making it, to mitigate the effect of such a fire on chemical oxygen generators contained in the packaging. 
         [0007]    The National Transportation Safety Board (NTSB) determined that one of the probable causes of the May 11, 1996 crash of ValuJet Airlines flight No. 592 was a fire in the airplane&#39;s cargo compartment initiated and enhanced by the actuation of one or more chemical oxygen generators carried as cargo in violation of requirements in the Hazardous Materials Regulations (HMR 49 CFR Parts 171 through 180). Recommendations issued by the NTSB following this tragedy addressed both the initiation of the fire by the improperly packaged generators and the possible enhancement of an aircraft cargo-compartment fire by the oxygen produced by the generators or other cargo. A number of corrective measures were included in NTSB Docket HM-224A. The final rule pointed out the possibility of further reducing the risks by enclosure of boxes containing chemical oxygen generators in an overpack or outer packaging meeting certain flame penetration resistance, thermal protection and integrity standards. 
         [0008]    Later rule-making procedures addressed the additional features of flame penetration resistance, thermal protection and integrity. In 2007, the Department of Transportation, Pipeline and Hazardous Materials Safety Administration, issued final rule HM224B, “Transportation of Compressed Oxygen, Other Oxidizing Gases and Chemical Oxygen Generators on Aircraft.” This regulation specifies that after Sep. 30, 2009, a chemical oxygen generator and a chemical oxygen generator installed in equipment, must be placed in a rigid outer packaging that, among other things, conforms to the requirements of The Flame Penetration Resistance Test in part III of Appendix F to 14 CFR part 25, applied to at least three specimens of the outer packaging of a specified dimension, and on all design features, within five minutes of application of the flame source; and the maximum allowable temperature at a point four inches above the test specimen, centered over the burner cone, must not exceed 205° C. (400° F.). Furthermore, a chemical oxygen generator in the rigid outer packaging, when placed in a 205° C. (400° F.) oven for three hours must not actuate. 
         [0009]    Present packaging aimed at satisfying these requirements is bulky, complicated to assemble, and unduly expensive, or all three. 
     
    
     
       DRAWINGS 
         [0010]      FIGS. 1 through 14  illustrate the making and assembly of embodiments of the packaging system. 
           [0011]      FIG. 1  shows an exemplary cardboard outer box, laid flat. 
           [0012]      FIG. 2  shows a perspective cut-away view of the exemplary cardboard box, as the same would appear folded to create the outer box structure. 
           [0013]      FIG. 3  shows a foil flat for the liner of the cardboard box. 
           [0014]      FIG. 4  shows a flat of ceramic fibers that cooperates with the folded foil flat of  FIG. 3 . 
           [0015]      FIG. 5  shows a typical pattern for hot melt glue suitable for attaching the flat of ceramic fiber of  FIG. 4  to the foil flat of  FIG. 3 . 
           [0016]      FIG. 6  shows a perspective cut-away view of the exemplary foil and ceramic fiber insert that is located inside the cardboard box of  FIG. 2 . 
           [0017]      FIG. 7  is a perspective view of a foil patch for covering seams and staples within the assembled embodiment. 
           [0018]      FIG. 8  is a ceramic fiber insert for the patch of  FIG. 7   
           [0019]      FIG. 9  shows the assembly of the foil patch and the ceramic fiber insert of  FIGS. 7 and 8 . 
           [0020]      FIG. 10  shows a typical pattern of neoprene glue used for assembly of the foil patch and the ceramic fiber insert of  FIGS. 7 and 8 . 
           [0021]      FIG. 11  is an exploded view of the components of an embodiment of the packaging system. 
           [0022]      FIG. 12  is a perspective view of an end insert for the packaging system container, constructed of foil and ceramic fiber. 
           [0023]      FIG. 13  shows an exploded view of the construction of the end insert of  FIG. 12 . 
           [0024]      FIG. 14  is a perspective cut-away view of an exemplary packaging system, assembled. 
           [0025]      FIG. 14A  shows cross-section details of the layers of the exemplary packaging system. 
           [0026]      FIGS. 15 through 28  illustrate exemplary steps of assembly of components of the packaging system into a container for shipping heat and flame sensitive articles. 
       
    
    
       [0027]    The drawings are not to scale. 
       DESCRIPTION 
       [0028]    An “overpack,” is the container for a sensitive chemical cargo that is usually enclosed in some sort of primary packaging. The disclosed overpack comprises a box ( 110 ), preferably double-walled cardboard, which is lined with layers of metal foil and ceramic fiber paper that form an inner liner ( 160 ). The size and shape of the box ( 110 ) is determined by the number and size of containers to be placed in it. In one embodiment, the contents may be one or a number of individually packaged devices, such as chemical oxygen generators. (The reader should understand that the term “oxygen generator” in this application refers generally to any heat or flame-sensitive component of product.) 
         [0029]    Flame penetration resistance can be provided by ceramic papers, felts or fabrics such as those offered by Unifrax, of Niagara Falls, N.Y., under the trade name of FIBERFRAX. For this purpose, such sheets of ceramic fiber (interchangeably called “felt,” “paper” or “fabric” in this application), preferably 1/16 inch to ¼ inch thick, preferably about ⅛ inch thick, are attached to one side of a cardboard carton. Such cartons are preferably double wall, 275 lb test, for shipping integrity. Packaging material other than cardboard could be used. The overall size and shape of the cardboard carton will be determined by the size of the container or equipment it will receive, allowing space for the ceramic fiber sheets, metal foil, and assembly means. 
         [0030]    Metal foil ( 130 ), preferably aluminum foil, having a thickness of about 1 mil to 4 mils, preferably about 2 mils, provides a serviceable surface and protects the included ceramic paper ( 140 ). The foil ( 130 ) also prevents penetration of the compartment ( 225 ) by hot gasses from flames. Parts of the foil ( 130 ) will also be the points of attachment of the foil ( 130 ) and the ceramic paper ( 140 ) to the box ( 110 ). All surfaces of the ceramic paper ( 140 ) that will, at one time or another, be visible looking into the compartment ( 225 ) are covered with foil ( 130 ), and, where needed, additional foil ( 130 ) is provided for bonding. Any of a number of adhesive means are adequate; hot melt adhesive has been found suitable. An example of a suitable hot melt glue is Technomelt from Henkel Adhesives, of Elgin, Illinois. The surface of the foil ( 130 ) that will contact the included contents provides additional advantages of low coefficient of friction, allowing the intended contents to be slid into the box, and low emissivity, which slows heat transfer from a flame to the contents. 
         [0031]    The figures illustrate the construction of the box with the liner ( 160 ) of foil ( 130 ) and ceramic fiber ( 140 ), per the following table of reference numerals: 
         [0000]    
       
         
               
               
             
           
               
                   
               
               
                 Reference 
                   
               
               
                 numeral 
                 Item 
               
               
                   
               
             
             
               
                 100 
                 assembled packaging system 
               
               
                 110 
                 cardboard box form 
               
               
                 120 
                 fold lines 
               
               
                 130 
                 foil for liner 
               
               
                 140 
                 ceramic fiber flat for liner 
               
               
                 150 
                 ceramic fiber hot melt glue pattern for liner 
               
               
                 160 
                 folded foil and ceramic fiber insert in box pattern 
               
               
                 165 
                 edges of ceramic fiber/foil liner to be joined 
               
               
                 170 
                 foil for patch 
               
               
                 180 
                 ceramic fiber for patch 
               
               
                 190 
                 foil plus ceramic fiber patch folded for application 
               
               
                 195 
                 seam made at edges of liner 
               
               
                 200 
                 neoprene glue pattern for patch 
               
               
                 210 
                 staples 
               
               
                 220 
                 assembled end insert 
               
               
                 225 
                 compartment formed by fiber/foil 
               
               
                 230 
                 inner foil for end insert 
               
               
                 240 
                 ceramic fiber for end insert 
               
               
                 250 
                 outer foil for end insert 
               
               
                 260 
                 labels for outer foil of end insert 
               
               
                 270 
                 assembled packaging system 
               
               
                 280 
                 short end flaps of box 
               
               
                 290 
                 long end flaps of box 
               
               
                 300 
                 tape for sealing box 
               
               
                   
               
             
          
         
       
     
         [0032]      FIG. 1  shows an exemplary cardboard outer box ( 110 ), laid flat, having scoring for folding.  FIG. 2  shows a perspective cut-away view of the exemplary cardboard box ( 110 ), as the same would appear folded to create the box ( 110 ) structure for transport of an article.  FIG. 3  shows a foil flat ( 130 ) for the liner ( 160 ) of the cardboard box ( 110 ).  FIG. 4  shows a flat ( 140 ) of ceramic fiber that cooperates with the foil flat ( 130 ) of  FIG. 3  to create the ceramic fiber-foil inner liner ( 160 ) of the packaging system ( 100 ).  FIG. 5  shows a pattern ( 150 ) for hot melt glue suitable for attaching the flat of ceramic fibers ( 140 ) of  FIG. 4  to the foil flat ( 130 ) of  FIG. 3 . 
         [0033]    After a laid-flat box ( 110 ) has been thus equipped with a ceramic paper and aluminum foil liner ( 160 ) as shown in the figures, the edges ( 165 ) of the liner ( 160 ) are lapped and stapled to make a joint or seam ( 195 ). 
         [0034]      FIG. 6  is a perspective cut-away view of the assembled packaging system ( 100 ) before the patch ( 190 ) is applied over the seam ( 195 ) where the edges ( 165 ) of the inner liner ( 160 ) are abutted.  FIG. 6  shows the liner ( 160 ) of foil ( 130 ) and ceramic fiber ( 140 ), inside the cardboard box ( 110 ), revealing the seam ( 195 ) and staples ( 210 ) to be covered by the patch ( 190 ), as discussed next. 
         [0035]    The stapled seam ( 195 ) is covered with a patch ( 190 ) of ceramic paper ( 180 ) and metal foil ( 170 ), the various parts being bonded over the seam ( 195 ) using any of a variety of adhesives. We have found that neoprene glue is adequate. The foil side of the patch ( 190 ) should face the compartment ( 225 ). 
         [0036]      FIG. 7  is a perspective view of a foil layer ( 170 ) for a patch ( 190 ) for covering the seam ( 195 ) and staples ( 210 ) within the assembled embodiment of the packaging system ( 100 ).  FIG. 8  shows a ceramic fiber insert layer ( 180 ) that cooperates with the foil layer ( 170 ) shown in  FIG. 7  to form the patch ( 190 ).  FIG. 9  shows the assembly of the foil layer ( 170 ) and the ceramic fiber layer ( 180 ) for the patch ( 190 ), folded as it would be applied inside the liner ( 160 ) over the seam ( 195 ).  FIG. 10  shows a typical pattern ( 200 ) of a neoprene glue application used for assembly of the foil layer ( 170 ) and the ceramic fiber layer ( 180 ) into the patch ( 190 ). 
         [0037]      FIG. 11 , not to scale, is an exploded view of the components of the packaging system ( 100 ) just discussed, as they would appear before the edges ( 165 ) of the combined foil ( 130 ) and ceramic fiber ( 140 ) layers are joined. 
         [0038]      FIGS. 12 and 13  show the exemplary construction of an end insert ( 220 ) for covering the ends of the compartment ( 225 ) when the inner liner ( 160 ) is folded. The end insert ( 220 ) has a foil layer ( 230 ) over a layer ( 250 ) of ceramic fiber. An exploded assembly view of the end insert ( 220 ) is shown in  FIG. 13 .  FIG. 13  shows a second, optional, foil layer ( 250 ) over the ceramic fiber layer ( 240 ), and also optional labels ( 260 ) to instruct the person assembling the system ( 100 ) that the continuous foil layer ( 230 ) should face toward the interior of the compartment ( 225 ). 
         [0039]      FIG. 14  is a cut-away perspective view of the assembled packaging system, with the outer box ( 110 ), inner liner ( 160 ), patch ( 190 ) and end insert ( 220 ) in place. The end inserts ( 220 ) are used to assure substantially complete and continuous coverage of the ends of the compartment ( 225 ) where the liner ( 160 ) is folded, to block penetration of the compartment ( 225 ) of the box by hot gasses. Before the end inserts ( 220 ) are placed and the ends of the box ( 110 ) are closed, the open box ( 110 ) with the liner ( 160 ) inside can be collapsed, and multiple collapsed systems ( 100 ) can be stacked for storage and shipment. 
         [0040]    Note that the box ( 110 ) may be any convenient size and shape, not necessarily the rectangular cross-section box ( 110 ) shown. In some embodiments, the staples ( 210 ) enter the wall of the box ( 110 ) and pass through the liner ( 160 ), thus attaching the liner ( 160 ) to the box ( 110 ). 
         [0041]    A drawing of a schematic cross section of the wall of the flame resistant packaging system ( 100 ) is shown in  FIG. 14A . 
         [0042]    When the flame penetration-resistant system ( 100 ) is needed for shipment, it can be prepared for receiving and article to be transported according to the following steps, as generally illustrated in  FIGS. 15-28 . 
         [0043]    The assembled and flattened packaging system ( 100 ) is retrieved from a storage location and placed on a workspace. 
         [0044]    In  FIG. 15 , the system ( 100 ) is unfolded into a rectangular, open shape. 
         [0045]    In  FIG. 16 , the liner ( 160 ) is scored with the fingers along all horizontal fold lines in the liner ( 160 ), to assist with proper folding of the foil and ceramic felt inner lining ( 160 ) to correspond to the horizontal fold lines of the cardboard box ( 110 ). 
         [0046]    In  FIGS. 17 and 18 , the inner lining ( 160 ) is folded into the box ( 110 ) so that it is perpendicular to the outer body of the box ( 110 ), thus substantially closing the open end of the compartment ( 225 ). Merely for illustration, the box ( 110 ) in these examples is shown with a rectangular cross section, having a short side ( 280 ) and a long side ( 290 ). 
         [0047]    In  FIG. 19 , the short sides ( 280 ) of the box ( 110 ) are folded, and then the long sides ( 290 ) are folded, completing closing of the box ( 110 ) on the end shown upright. 
         [0048]    In  FIG. 20 , the folded bottom of the box ( 110 ) is secured using an “H” pattern of tape ( 300 ). A three-inch industrial grade tape with fiberglass yarn is preferred. 
         [0049]    In  FIG. 21 , the previously secured bottom of the box ( 110 ) is placed on the workspace and the bottom end insert ( 220 ) is placed into the compartment ( 225 ) over the folded end of the liner ( 160 ), with the foil side of the insert ( 220 ) facing the compartment ( 225 ). Preferably, the insert ( 220 ) has labels ( 260 ) indicating the proper direction of placement. 
         [0050]      FIG. 22  shows the inside of the system ( 100 ) with the correctly installed bottom insert ( 220 ). 
         [0051]    In  FIG. 23 , the liner ( 160 ) is scored with the fingers along all horizontal fold lines in the liner ( 160 ) to assist with proper folding of the foil and ceramic felt liner ( 160 ) to correspond to the horizontal fold lines of the cardboard box ( 110 ). 
         [0052]    In  FIG. 24 , the article to be shipped and any dunnage (not shown) are placed into the compartment ( 225 ) and the second end insert ( 220 ) is placed on top of the dunnage and article. The insert ( 220 ) should be substantially flush on the contents of the compartment ( 225 ). 
         [0053]    In  FIG. 25 , a flap of the liner ( 160 ) is folded into the box ( 110 ) so that it is perpendicular to the outer body of the box ( 110 ). 
         [0054]    In  FIG. 26 , the other flap of the liner ( 160 ) is folded into the box ( 110 ) so that it is perpendicular to the outer body of the box ( 110 ). 
         [0055]    In  FIG. 27 , the short sides ( 280 ) of the box ( 110 ) are folded; then the long sides ( 290 ) are folded, completing closing of the box ( 110 ) on the end shown upright. 
         [0056]    In  FIG. 28 , the folded bottom of the box ( 110 ) is secured using an “H” pattern of tape ( 300 ). A three-inch industrial grade tape with fiberglass yarn is preferred. This completes a sealed packaging system ( 270 ) with contents.