Abstract:
The fire extinguisher of the present invention includes a container housing a fire inhibiting material which may automatically discharge its fire inhibiting contents in response to a fire. In one exemplary embodiment, the fire inhibiting material is pressurized within the container and the container is structured and arranged to discharge its fire inhibiting contents in a predetermined direction. Also, a method is provided for constructing a container for holding fire inhibiting contents under pressure and a method and apparatus for effectively and efficiently filling and pressurizing the container with fire inhibiting material, forming a container structured and arranged to expel the fire inhibiting material contained therein in a predefined direction in response to a fire.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 60/675,329 entitled FIRE EXTINGUISHER filed on Apr. 27, 2005, the disclosure of which is expressly incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an apparatus for extinguishing fires as well as to methods and materials used to construct the fire extinguishing apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    Fire extinguishers generally operate to extinguish a fire by ejecting a fire inhibiting substance onto the fire. Fire extinguishers that automatically discharge a fire inhibiting substance in response to detection of a fire are useful in many circumstances. For example, should a fire break out in an area that is not readily accessible, a fire extinguisher that functions to discharge its fire inhibiting substance on the fire automatically in response to detection of the fire is very useful. One such automatic fire extinguisher is described in U.S. Pat. No. 5,909,776, the entire disclosure of which is hereby explicitly incorporated by reference herein. 
         [0006]    In the case of an automatic fire extinguisher, it is most useful to provide an extinguisher positioned and constructed to directly apply its fire inhibiting contents to the fire. 
       SUMMARY 
       [0007]    The fire extinguisher of the present invention includes a container housing a fire inhibiting material which may automatically discharge its fire inhibiting contents in response to a fire. In one exemplary embodiment, the fire inhibiting material is pressurized within the container and the container is structured and arranged to discharge its fire inhibiting contents in a predetermined direction. Also, a method is provided for constructing a container for holding fire inhibiting contents under pressure and a method and apparatus for effectively and efficiently filling and pressurizing the container with fire inhibiting material, forming a container structured and arranged to expel the fire inhibiting material contained therein in a predefined direction in response to a fire. 
         [0008]    Advantageously, the present fire extinguisher can automatically discharge when the temperature around the fire extinguisher rises above a predetermined point, allowing for the fire extinguisher to quench a fire without the need for human intervention. Additionally, the fire extinguisher may be constructed to discharge its contents in a predetermined direction, protecting the most vital areas of a given structure, such as the tires or engine of a motor vehicle. 
         [0009]    In one form thereof, the present invention provides a fire extinguisher, including: a container including a wall having a first thickness and defining an interior cavity, and a discharge window formed as a substantial area of the wall, the discharge window having a second thickness which is less than the first thickness; and a quantity of fire inhibiting substance contained within the interior cavity, the fire inhibiting substance expandable at an elevated temperature to discharge through the discharge window along a focused direction substantially defined by the discharge window. 
         [0010]    In another form thereof, the present invention provides a fire extinguisher, including: a container including a wall defining an interior cavity; a first fitting having an exterior surface including a groove, the first fitting received at least partially within an open first end of the container with at least a portion of the wall pressed into the groove; and a quantity of fire inhibiting substance contained within the tube, the fire inhibiting substance expandable at an elevated temperature to discharge from the container. 
         [0011]    In another form thereof, the present invention provides a method of sealing a container, including the steps of: providing a container having a wall defining an interior cavity, and a fitting having an exterior surface including at least one groove; positioning the fitting within an open end of the container at least partially within the interior cavity; deforming the wall to press at least a portion of the wall into the groove. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above mentioned and other features of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an exemplary embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0013]      FIG. 1  is a perspective view of an exemplary fire extinguisher made in accordance with the present invention; 
           [0014]      FIG. 2  is a perspective view of a tube which forms a part of the fire extinguisher illustrated in  FIG. 1 ; 
           [0015]      FIG. 3  is a sectional view of the tube illustrated in  FIG. 2  taken along line  3 - 3  of  FIG. 2 ; 
           [0016]      FIG. 4  is a perspective view of a collar used to secure a fitting to an end of the tube forming a part of the fire extinguisher illustrated in  FIG. 1 ; 
           [0017]      FIG. 5  is a sectional view of the collar illustrated in  FIG. 4  taken along line  5 - 5  of  FIG. 4 ; 
           [0018]      FIG. 6  is a longitudinal fragmentary sectional view of the fire extinguisher illustrated in  FIG. 1 ; 
           [0019]      FIG. 7  is an exploded view of a fitting and associated pressure gauge for indicating the internal pressure of the fire extinguisher of  FIG. 6 ; 
           [0020]      FIG. 8  is a sectional view of the fitting illustrated in  FIG. 7 ; 
           [0021]      FIG. 9  is an exploded view of a fitting and associated valve and pressure switch, also illustrating a filling apparatus of the present invention useful to position fire inhibiting material within the fire extinguisher of  FIG. 1  and to pressurize the same; 
           [0022]      FIG. 10  is a sectional view of the fitting illustrated in  FIG. 9 , 
           [0023]      FIG. 11  is a sectional view of a pressure switch connector used to connect a pressure switch to a fitting closing an end of a fire extinguisher of  FIG. 1 ; 
           [0024]      FIG. 12  is a perspective view of a shaping device for milling a tube which forms a part of the fire extinguisher in  FIG. 1 ; 
           [0025]      FIG. 13  is a sectional view of an actuation device and tube guide forming a part of the shaping device illustrated in  FIG. 12 ; 
           [0026]      FIG. 14  is a sectional view illustrating a tube guide and actuation device in operable position to allow for milling a tube which forms a part of the fire extinguisher in  FIG. 1 ; 
           [0027]      FIGS. 15-17  are fragmentary sectional views illustrating progressive steps in a process of crimping a tube to a fitting to form an enclosure for a fire inhibiting substance; 
           [0028]      FIGS. 18-20  are perspective views of a tube filling apparatus of the present invention; and 
           [0029]      FIGS. 21 and 22  are partial sectional views of a fire extinguisher and valve body used to fill the fire extinguisher with a fire inhibiting substance and pressurize the same. 
       
    
    
       [0030]    Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION 
       [0031]    The embodiments disclosed below are not intended to be exhaustive or limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. 
         [0032]    Fire extinguisher  20 , as depicted in  FIG. 1  and described in detail below, forms an enclosure which may contain a fire inhibiting substance  28 , shown in  FIG. 6 . As the temperature around fire extinguisher  20  increases, fire inhibiting substance  28  expands, increasing the pressure within fire extinguisher  20 . When the temperature around fire extinguisher  20  reaches a set point, the pressure inside fire extinguisher  20  is high enough to cause tube  22  to burst and expel the fire inhibiting substance  28  through discharge window  30 , as described in detail below. 
         [0033]    Referring to  FIG. 1 , fire extinguisher  20  includes tube  22  having opposite ends  24 ,  26 . Tube  22  cooperates with opposite ends  24 ,  26  to form an enclosure containing a fire inhibiting substance  28 , shown in  FIG. 6 . Fire inhibiting substance  28  is, in one exemplary embodiment, a gelled halocarbon and dry chemical suspension marketed under the name ENVIROGEL by Powsus, Inc., 1178 Wisteria Drive, Malvern, Pa. 19355, ENVIROGEL is a trademark of Powsus, Inc. 1178 Wisteria Drive, Malvern, Pa. 19355. One exemplary composition of ENVIROGEL is made of up of 40% by weight gelled ammonium polyphosphate and 60% by weight HFC-236fa. Other exemplary fire inhibiting substances are disclosed in U.S. Pat. Nos. 5,833,874; 5,466,386; 5,909,776; and 6,736,989, each assigned to Powsus, Inc., the entire disclosures of which are hereby explicitly incorporated by reference herein. 
         [0034]    As illustrated in  FIGS. 1-3  and  6 , tube  22  includes discharge window  30 . Referring to  FIG. 3 , tube wall  32  of tube  22  includes an area of decreased thickness forming discharge window  30 , which defines an outer perimeter and covers a substantial area. In one embodiment, the outer perimeter has a substantially rectangular shape. Additionally, discharge window  30  defines a focused direction for discharge of fire inhibiting substance  28 . Owing to the decreased wall thickness of discharge window  30 , fire inhibiting substance  28  will be most readily released from fire extinguisher  20  through discharge window  30 , as further described hereinbelow. In use, discharge window  30  of fire extinguisher  20  provides a focused direction for the release of fire inhibiting substance  28 , shown in  FIG. 6 , therefrom. 
         [0035]    As described in detail below, fire inhibiting substance  28  is placed under pressure in fire extinguisher  20 . In one exemplary embodiment, the walls of tube  22  are resistant to the pressure contained within tube  22  at temperatures below 120° F. In one exemplary embodiment, the pressure contained within tube  22  is approximately 100 psi. When tube  22  is heated above 120° F., fire inhibiting substance  28  expands placing additional internal pressure on the walls of tube  22  causing tube  22  to burst and expel fire inhibiting substance  28  contained therein. Because discharge window  30  has a smaller wall thickness than the remainder of tube  22 , tube  22  is more likely to burst at discharge window  30  and fire inhibiting substance  28  is most readily discharged from tube  22  through discharge window  30  along a focused direction as defined above. 
       Fire Extinguisher Structure 
       [0036]    Referring to  FIGS. 1-11 , the structure of fire extinguisher  20  will now be described in detail. Referring to  FIG. 6 , fire extinguisher  20  includes tube  22  and opposite ends  24 ,  26 . In one exemplary embodiment, tube  22  is formed of nylon. In a further embodiment, tube  22  is formed of ASCEND™ 67B high viscosity nylon, available, e.g., from Solutia Inc., 575 Maryvill Centre Drive, St. Louis, Mo. 63166. In another embodiment, tube  22  is formed of a nylon resin, such as DuPont Zytel® nylon resin, available from E.I duPont de Nemours &amp; Co., Wilmington, Del. 19880, and, in particular, Zytel® 45HSB NC010 nylon resin. Zytel® is a registered trademark of E.I duPont de Nemours &amp; Co., Wilmington, Del. 19880. Opposite ends  24 ,  26  each include a fitting  36 ,  34 , respectively, positioned within tube  22  as well as collars  38  surrounding at least portions of tube  22  and fittings  34 ,  36 . Collars  38  crimp the ends of tube  22  to fittings  34 ,  36  to create a sealed enclosure for fire inhibiting substance  28 . In one exemplary embodiment, fire inhibiting substance  28  occupies approximately 95% of the enclosure created by tube  22 , fittings  34 ,  36  and collars  38 . The remaining space of the enclosure is, in one exemplary embodiment, filled with an inert gas such as nitrogen. As further described hereinbelow, the materials contained within fire extinguisher  20  may be pressurized to about 100 psi. 
         [0037]    Referring to  FIGS. 6-8 , fitting  34  includes annular grooves  40 . Referring to  FIGS. 6 ,  9  and  10 , fitting  36  similarly includes annular grooves  48 . During the process of constructing fire extinguisher  20 , further described hereinbelow, the ends of tube  22  are heated until the material forming tube wall  32  is flowable. The heated tube ends are thereafter positioned over fittings  34 ,  36 . Collars  38  are thereafter positioned over the ends of tube  22  and the associated fittings  34 ,  36 , capturing wall  32  between the exterior of fittings  34 ,  36  and collars  38 , and causing the flowable material of tube wall  32  to occupy annular grooves  40 ,  48 . The process for constructing fire extinguisher  20 , including opposite ends  24 ,  26  is described in greater detail hereinbelow. 
         [0038]    As illustrated in  FIGS. 1 and 6 , pressure gauge  42  is connected to fitting  34  and is in fluid communication with the interior of fire extinguisher  20 . In the embodiment illustrated, pressure gauge  42  includes threaded boss  44  sized to threadingly engage threaded internal bore  46  of fitting  34 . Threaded internal bore  46  of fitting  34  allows pressure gauge  42  to fluidly communicate with the interior of fire extinguisher  20  so that pressure gauge  42  is operable to measure and display the internal pressure of fire extinguisher  20 . 
         [0039]    Fitting  36  is illustrated in  FIGS. 6 ,  9 , and  10  and includes annular grooves  48  similar to annular grooves  40  of fitting  34 . As illustrated in  FIG. 6 , material of tube wall  32  flows into and occupies annular grooves  48  of fitting  36  in the final construct of fire extinguisher  20 , as discussed above. As illustrated in  FIGS. 6 and 10 , fitting  36  includes internal aperture  50  having threaded sections  52 ,  54 . Referring to  FIGS. 6 ,  9 , and  10 , threaded section  52  of internal aperture  50  is sized to accommodate valve  56  threadedly engaged therein. Valve  56  includes O-ring  58  positioned about the exterior thereof. O-ring  58  facilitates sealing between the exterior of valve  56  and internal aperture  50  of fitting  36 . Valve  56  includes valve stem  60  having valve cover  62  connected to one end thereof. Valve cover  62  includes O-ring  64  operably positioned about the periphery thereof to facilitate sealing of valve cover  62  with valve seat  66 . 
         [0040]      FIG. 9  is an exploded view showing valve  56  prior to being secured within threaded section  52  of internal aperture  50 . Valve  56  is illustrated in its closed position in  FIG. 9 . Flange  68  is connected to the end of valve stem  60  opposite valve cover  62 . As illustrated in  FIG. 9 , valve  56  includes support  70 . Spring  72  is positioned about valve stem  60  intermediate flange  68  and support  70  and acts to bias valve  56  into its closed position, as illustrated in  FIG. 9 . Valve  56  includes a generally cylindrical body terminating at one end in valve seat  66 , shown in  FIG. 6 , and having an opening at the other end. The end of the cylindrical body of valve  56  opposite valve seat  66  includes support  70  extending therefrom. Actuation of flange  68  towards support  70  against the bias of spring  72  acts to open valve  56  and allow fluid flow through valve  56  and thereafter past valve seat  66 . 
         [0041]    Referring still to  FIGS. 6 and 9 , pressure switch connector  74  is threadedly engaged in threaded section  54  of internal aperture  50  of fitting  36 . Pressure switch connector  74  includes flange  76  which, in construction, abuts shoulder  78  of fitting  36  to facilitate making a seal therebetween. As illustrated in  FIGS. 9 and 11 , connector  74  includes central detent  80 . Central detent  80  has an internal diameter slightly greater than the external diameter of flange  68  of valve  56 , so that with pressure switch connecter  74  threadedly engaged with fitting  36 , as illustrated in  FIG. 6 , flange  68  is positioned within central detent  80  of connector  74 . 
         [0042]    As illustrated in  FIG. 6 , connector  74  includes internal threaded bore  82  in fluid communication with fluid passage  84 . As illustrated in  FIG. 6 , with connector  74  threadedly engaged with fitting  36 , flange  68  of valve  56  is positioned within central detent  80  of connector  74  and connector  74  forces flange  68  to move against the biasing force of spring  72  toward support  70  to unseat valve cover  62  from valve seat  66 . In this position, fluid contained within tube  22  can flow through valve  56  and fluid passage  84 . Referring to  FIGS. 6 and 9 , pressure switch  86  is threadedly engaged in internal threaded bore  82  of connector  74 . With the construct shown in  FIG. 6 , pressure switch  86  is in fluid communication with the contents of tube  22  through fluid passage  84  and valve  56 , and is operable to provide a signal to a computational device indicative of whether the pressure in tube  22  drops below a predetermined value. For example, in a vehicle the pressure switch may signal a computational device that activates a visual indication device, such as a light bulb, mounted in the dashboard of the vehicle to provide a visual signal to the driver that the pressure in tube  22  is low. In certain embodiments, pressure gauge  42  and pressure switch  86  may not be desired. In these embodiments, fittings  34 ,  36  will have plugs operably associated therewith to prevent fluid flow from passing through the internal bores of fittings  34 ,  36 . Alternatively, in embodiments in which pressure gauge  42  and pressure switch  86  are not desired, fittings  34 ,  36  may be formed as solid plugs, i.e., without internal bores  46 ,  50 , respectively. 
         [0043]    In use, fire extinguisher  20  is positioned such that discharge window  30  opens toward a particular area at potential risk for fire. For example, certain military vehicles are sometimes susceptible to having small combustible devices, such as “Molotov cocktails,” detonated within their wheel wells in an attempt to render the vehicle inoperable. In these circumstances, fire extinguisher  20  can be positioned with discharge window  30  pointed downwardly away from the vehicle&#39;s wheel well and toward the vehicle&#39;s tire. With this configuration, if a combustible device is exploded within the wheel well of the vehicle, the sudden rise in temperature will cause tube  22  to soften and rupture against the force of its expanding, pressurized contents, thereby dispensing fire inhibiting substance  28  within the wheel well and extinguishing the fire. 
       Method and Apparatus for Forming Discharge Window  30  in Tube  22   
       [0044]    Referring to  FIG. 12 , shaping device  90  is utilized to form discharge window  30  in tube  22 . Specifically, shaping device  90  is utilized to mill discharge window  30  in tubular stock material utilized to create tube  22  of fire extinguisher  20 . In one exemplary embodiment, raw tubing used to form tube  22  has a wall thickness of 0.065 inches and shaping device  90  is utilized to mill off 0.010 inches of wall material to create discharge window  30 , shown in  FIG. 1 . Discharge window  30  defines an outer perimeter and covers a substantial area of the outer surface of tube  22 , which can constitute as little as 5%, 10% or 15% of the surface area of the outer surface of tube  22  excluding ends  24 ,  26  and as much as 40%, 45%, or 50% of the surface area of the outer surface of tube  22  excluding ends  24 ,  26 . In one embodiment, tube  22  measures 8 inches long and ½ inches in diameter and includes a discharge window constituting 11.6 percent of total surface area of the outside of the tube. In another embodiment, tube  22  measuring 27 inches long and ½ inches in diameter is formed to include a discharge window constituting 16.8 percent of the total surface area of the outside of the tube. Shaping device  90  includes tube guide  92  and tool  94 . Tool  94  includes radiused cutting surface  96  having a radius of curvature substantially matching the radius of the raw tube material used to form tube  22  of fire extinguisher  20 , shown in  FIG. 1 . 
         [0045]    As illustrated in  FIGS. 12-14 , tool  94  is operatively connected to chuck  98 . Chuck  98  is operably connected to a motor utilized to rotate chuck  98  as is well known in the art. Tube guide  92  includes elongate aperture  100  formed throughout its length. Elongate aperture  100  has an inner diameter just slightly larger than the outer diameter of the stock material utilized to form tube  22  of fire extinguisher  20 , shown in  FIG. 1 . As illustrated in  FIGS. 12-14 , tube guide  92  includes tool cutout  102  formed in a wall thereof. Specifically, tool cutout  102  is formed as a slot in the wall of tube guide  92  facing tool  94 . Tool cutout  102  intersects elongate aperture  100  of tube guide  92  to provide an access through which tool  94  contacts tube  22  as shown in  FIG. 14 . 
         [0046]    Referring to  FIGS. 13 and 14 , shaping device  90  includes pneumatic cylinder  104  including pneumatic piston  106 . Pneumatic piston  106  is threadedly engaged with rod  108 . In one exemplary embodiment, rod  108  is a brass rod. Rod  108  occupies rod channel  110  in tube guide  92 . Rod channel  110  intersects elongate aperture  100  of tube guide  92  so that rod  108  can be positioned in abutting relationship with tube  22  as shown in  FIG. 14 . 
         [0047]    Pneumatic cylinder  104  is utilized to move pneumatic piston  106  and, consequently, rod  108  to facilitate milling of tube  22 .  FIG. 13  illustrates pneumatic piston  106  in a withdrawn position. Consequently, rod  108  is also in a withdrawn position. In its withdrawn position, rod  108  does not apply a significant normal force to tube  22  and, therefore, does not significantly impede progress of tube  22  through tube guide  92 .  FIG. 14  illustrates pneumatic piston  106  actuated to position rod  108  in abutting relationship with tube  22 . In this position, rod  108  applies a normal force to tube  22  to thereby frictionally resist movement of tube  22  through tube guide  92  and to insure that tube  22  is flush with the portion of the interior wall of tube guide  92  formed by elongate aperture  100  which is closest to tool  94 . With tube  22  flush with this interior wall of tube guide  92 , tool  94  can be operably positioned against tube  22  to effect milling thereof as illustrated in  FIG. 14 . In one exemplary embodiment, air source  144  is utilized to provide a stream of air directed to tool  94  during the milling process. It has been found that the provision of a stream of air during milling facilitates creation of discharge window  30  by removing debris, such as shavings, that could interfere with the milling process. Additionally, the use of a stream of air cools tool  94  during the milling process. 
         [0048]    The normal force applied by rod  108  to tube  22  is sufficient to position tube  22  in the position illustrated in  FIG. 14  for milling, as described above, but also creates a small enough frictional resistance to passage of tube  22  through elongate aperture  100  so that tube  22  may be longitudinally displaced through elongate aperture  100  to effect milling of discharge window  30 , shown in  FIG. 1 . In one exemplary embodiment, rod  108  if formed of brass to prevent scarring of tube  22  as it passes through elongate aperture  100  during the milling process. Other relatively soft materials may be used to form rod  108  to prevent scarring. In one embodiment, tube  22  may be advanced through elongate aperture  100 , in contact with rod  108 , either by a mechanical controller, not shown, or by the application of force from the operator of shaping device  90 . 
         [0049]    Shaping device  90  further includes actuation device  112 . Actuation device  112  moves relative to the remaining structure of shaping device  90  to position tube  22  into engagement with tool  94  as illustrated in  FIG. 14  and out of engagement with tool  94  as illustrated in  FIG. 13 . In this exemplary embodiment, tube  22  is moved relative to tool  94  which remains stationary. In further embodiments of the present invention, tube  22  could remain stationary, with tool  94  being moved into and out of position to mill tube  22 . Further, both tube  22  and tool  94  could be moved to position tube  22  and tool  94  to allow for milling of tube  22  and to move one or both of tube  22  and tool  94  out of position whereby tool  94  cannot effect milling of tube  22 . 
         [0050]    Referring to  FIGS. 12-14 , shaping device  90  includes bed  114  with walls  116  extending upwardly therefrom. Upwardly extending walls  116  may be part of a clamping mechanism utilized to clamp items to bed  114  of shaping device  90 . Upwardly extending walls  116  may further be formed as stationary walls extending upwardly from bed  114 . As illustrated in  FIGS. 12-14 , actuation device  112  is positioned intermediate upwardly extending walls  116 . Referring to  FIGS. 13 and 14 , rod  118  is secured to each of upwardly extending walls  116 . As illustrated in  FIGS. 13 and 14 , pneumatic piston  120  is fixably secured to rod  118 . Pneumatic piston  120  is operably positioned within pneumatic cylinder  122  for reciprocation therein. Pneumatic cylinder  122  is formed in cylinder housing  124 . Cylinder housing  124  is positioned above bed  114  with a slight spacing therebetween. The spacing between cylinder housing  124  and bed  114  allows cylinder housing  124  to reciprocate between upwardly extending walls  116  as will be further described hereinbelow. With rod  118  secured to upwardly extending walls  116  and cylinder housing  124  free to move therebetween, actuation of actuation device  112  causes movement of cylinder housing  124  along rod  118 . 
         [0051]    Pneumatic piston  120  is sealed against pneumatic cylinder  122  in a conventional manner. Pneumatic piston  120  separates pneumatic cylinder  122  into two chambers  126 ,  128 . To actuate actuation device  112  so that tube  22  is brought into operative contact with tool  94  as illustrated in  FIG. 14 , compressed air is introduced into chamber  126  to cause cylinder housing  124  to achieve the position illustrated in  FIG. 14 . In certain embodiments, chamber  128  will include a resilient member positioned between pneumatic piston  120  and wall  130  of cylinder housing  124  so that cylinder housing  124  normally maintains the unactuated position illustrated in  FIG. 13 . In alternative embodiments, airlines  132 , shown in  FIG. 12 , can be fluidly connected one each to chambers  126 ,  128 . In this embodiment, airlines  132  are utilized to introduce compressed air alternatively into one of chambers  126 ,  128 , depending upon whether the operator of shaping device  90  wishes to position tool  94  in operative contact with tube  22 . Specifically, introduction of compressed air into chamber  126  will position tool  94  in operative engagement with tube  22  as illustrated in  FIG. 14 . Similarly, introduction of compressed air into chamber  128  will cause actuation of actuation device  112  into the position illustrated in  FIG. 13 , in which tool  94  is positioned a distance from tube  22 . 
         [0052]    In use, shaping device  90  is initially positioned as illustrated in  FIGS. 12 and 13 , i.e., with tool  94  positioned a distance from tube guide  92 . Tube  22  is then positioned within elongate aperture  100  of tube guide  92 . Because discharge window  30 , shown in  FIG. 1 , does not run the entire length of tube  22 , tube  22  is advanced through elongate aperture  100  until the end of tube  22  passes tool cutout  102  by a predetermined distance. In one embodiment, that predetermined distance is defined by the distance between wall  134  of tube guide  92  and tool cutout  102 . In this embodiment, tube  22  is advanced, as described above, until its end is flush with wall  134 . With tube  22  in this position, pneumatic cylinder  104  is actuated to bring rod  108  into frictional engagement with tube  22  as described in detail above. Actuation device  112  is then actuated by introducing compressed air into chamber  126 , shown in  FIG. 14 , of pneumatic cylinder  122  until actuation device  112  achieves the position illustrated in  FIG. 14 , with tool  94  operatively contacting tube  22 . With actuation device  112  positioned as illustrated in  FIG. 14 , tube  22  is advanced through tube guide  92  at a sufficient pace to allow tool  94  to mill discharge window  30  into tube  22 , shown in  FIG. 1 . 
         [0053]    As described above and shown in the drawings accompanying this description, discharge window  30  does not run the entire length of tube  22 . Therefore, milling is stopped before tube  22  is completely advanced through tube guide  92 . In one embodiment, tube  22  is inserted through elongate aperture  100  at surface  136  of guide tool  92 . However, tube  22  can also be inserted through elongate aperture  100  beginning at surface  134  of tool guide  92 . In one embodiment, the distance between the trailing end of tube  22 , the trailing end of tube  22  being determined relative to the tube&#39;s advancement through tube guide  92 , and the predetermined end of discharge window  30  proximate the trailing end of tube  22 , is the same as the distance from tool cutout  102  to trailing wall  136  of tube guide  92 . With this in mind, milling is stopped when the trailing end of tube  22  is flush with trailing wall  136  of tube guide  92 . With tube  22  advanced until its trailing end is flush with trailing wall  136  of tube guide  92 , actuation device  112  is moved into the position illustrated in  FIGS. 12 and 13  and tube  22  is removed from tube guide  92 . In one embodiment of the present invention, a tube cutter, not shown, may be positioned adjacent trailing wall  136  of tube guide  92  to allow for cutting a continuous feed of tube stock into tubes  22  of desired length. 
       Sealing of Fire Extinguisher Tube 
       [0054]    Referring to  FIGS. 1 and 6 , fire extinguisher  20  includes tube  22  and opposite ends  24 ,  26 . Opposite ends  24 ,  26  each include a fitting  36 ,  34 , respectively, positioned within tube  22  as well as collars  38  surrounding a portion of tube  22  and fittings  34 ,  36 . The process of forming opposite ends  24 ,  26  will now be described in detail with specific reference to end  26 . Referring to  FIGS. 15-17 , construction of end  26  begins by heating the end of tube  22  which will be placed over fitting  34  as illustrated in  FIGS. 15-17 . Specifically, the end of tube  22  is heated until the material forming tube wall  32  is flowable. In one exemplary embodiment, a heated basin is filled with sand and is thereafter raised to a temperature sufficient to heat tube  22  until the material of tube wall  32  is flowable. In the exemplary embodiment described herein, the basin is heated to 250° F. The basin can be heated to temperatures as low as 210° F., 215° F., 220° F., or 225° F. and as high as 260° F., 265° F., 270° F., or 275° F. The necessary heating temperature and time of heating are related and different combinations of time and temperature may be utilized to heat the end of tube  22  until the material forming tube wall  32  is flowable. 
         [0055]    After heating the end of tube  22  until the material formed in tube  22  is flowable, the heated tube end is positioned over fitting  34 , as illustrated in  FIG. 15 . As illustrated in  FIG. 15 , fitting  34  includes a first outer diameter D 1  slightly smaller than the inner diameter of tube  22 . First outer diameter D 1  terminates at shoulder  138 . Shoulder  138  forms a stop for tube  22 . That is, when end  26  of tube  22  is positioned over fitting  34 , progress of tube  22  over fitting  34  is restricted when the end  26  of tube  22  abuts shoulder  138 . Collar  38  is thereafter slid over end  26  of tube  22  in the direction of arrow A, shown in  FIG. 16 , until it is positioned over fitting  34 , as illustrated in  FIGS. 16 and 17 . In another embodiment, collar  38  could be slid over end  26  in the direction of arrow B, shown in  FIG. 16 . Collar  38  is sized to provide a tight fit over end  26  of tube  22  and apply a radially inward force, as illustrated in  FIG. 17 . Furthermore, collar  38  includes bevel  39 , as illustrated in  FIG. 5 , to facilitate placement of collar  38  over end  26  of tube  22 . The radially inward force supplied by collar  38  causes tube wall  32 , which is heated into a flowable condition, to press and flow into annular grooves  40  in fitting  34  and thereby create a robust seal between fitting  34  and tube  22 . As collar  38  applies the aforementioned radially inward force, material of tube wall  32  will naturally expand beyond shoulder  138 , as illustrated in  FIG. 17 . To accommodate expansion of tube wall  32  during the positioning of fitting  34  over end  26  of tube  22  described hereinabove, expansion area  140  is formed between fitting  34  and collar  38 . Expansion area  140  is sufficiently sized to accommodate expansion of tube wall  32  during the positioning of fitting  34  over end  26  of tube  22 . 
         [0056]    Referring to  FIG. 10 , fitting  36  at the other end  24  of tube  22  includes annular grooves  48  similar to annular grooves  40  formed in fitting  34 . Further, fitting  36  includes shoulder  142  similar to shoulder  138  of fitting  34 . Fitting  36  is sized similar to fitting  34  to allow for positioning of fitting  36  over end  24  of tube  22  in the same way described above with respect to fitting  34  and end  26  of tube  22 . 
         [0000]    Method and Apparatus for Filling the Fire Extinguisher with a Quantity of Fire Inhibiting Substance 
         [0057]    Referring to  FIG. 18 , tube filling apparatus  150  is utilized to fill fire extinguisher  20  with fire inhibiting substance  28 , shown in  FIG. 6 . Tube filling apparatus  150  includes valve body  152  connected to pneumatic cylinder  154 . Tube filling apparatus  150  further includes clamp  156  for holding fire extinguisher  20  during the process of filling the same with fire inhibiting substance  28 . Valve body  152  is connected to a source of fire inhibiting substance  28 , as well as a source of pressurized inert gas, and is used to fill fire extinguisher  20  with fire inhibiting substance and pressurize the same with a quantity of inert gas. 
         [0058]    Referring to  FIGS. 19 and 20 , the process of filling fire extinguisher  20  with fire inhibiting substance  28 , shown in  FIG. 6 , and pressurizing the same with an inert gas begins by positioning fire extinguisher  20  within clamp  156 . As illustrated in  FIG. 19 , clamp  156  includes brace  158  secured to frame  160 . As illustrated in  FIG. 20 , brace  158  includes internal bore  162 . Internal bore  162  is slightly larger than the outer diameter of tube  22 . To clamp fire extinguisher  20  in place, fire extinguisher  20  is first positioned within internal bore  162  of brace  158  as illustrated in  FIG. 19 . In this position, collar  38  abuts front face  164  of brace  158 . With fire extinguisher  20  positioned as illustrated in  FIG. 19 , removable brace block  166  is positioned as illustrated in  FIG. 20  and clamped against brace  158 . To clamp removable brace block  166  against brace  158 , lever  168  is actuated from the position shown in  FIG. 19  to the position shown in  FIG. 20 . Actuation of lever  168  in this way pushes clamp rod  171  against removable brace block  166  to clamp removable brace block  166  against brace  158 . Removable brace block  166  includes circular cutout  170 , shown in  FIG. 19 . Circular cutout  170  includes a radius of curvature slightly larger than the radius of the exterior of tube  22 . With removable brace block  166  clamped against brace  158  as illustrated in  FIG. 20 , collar  38  abuts front face  164  of brace  158  and front face  172  of removable brace block  166 . With fire extinguisher  20  clamped in place as illustrated in  FIG. 20 , valve body  152  can be moved into position to fill fire extinguisher  20  with fire inhibiting substance  28  and pressurize the same with an inert gas. 
         [0059]    As illustrated in  FIGS. 18 ,  21 , and  22 , valve body  152  is secured to pneumatic piston  174 . Pneumatic piston  174  is operatively connected to pneumatic cylinder  154  and is reciprocal relative thereto. Specifically, pneumatic piston  174  can be moved from a retracted position, as illustrated in  FIG. 21 , to an extended position, as illustrated in  FIG. 22 . Valve body  152  is maintained in the retracted position illustrated in  FIG. 21  while fire extinguisher  20  is operably positioned within clamp  156  in the manner described above. With fire extinguisher  20  positioned within clamp  156  as illustrated in  FIGS. 18 and 20 , valve body  152  can be actuated into the extended position illustrated in  FIG. 22 . As illustrated in  FIGS. 21 and 22 , pressure switch connector  74 , shown in  FIG. 6 , is not positioned within fitting  36  when fire extinguisher  20  is filled, such that tube filling apparatus  150  has access to valve  56  to effect filling of fire extinguisher  20 . As illustrated in  FIGS. 18-22 , valve body  152  includes actuation plunger  176  extending therefrom. Valve body  152  further includes fill boss  178  extending therefrom. Fill boss  178  includes a plurality of fill apertures  180 . As illustrated in  FIGS. 21 and 22 , fill apertures  180  provide access to fluid passages  182 ,  184 . Fluid passage  184  is operatively connected to a source of fire inhibiting substance  28  as well as a source of inert gas. 
         [0060]    Referring to  FIGS. 18-22 , valve body  152  includes a pair of fittings  186 ,  188  connected thereto and in fluid communication with fluid passage  184 . Fittings  186 ,  188  include fluid entrances  190 ,  192 , respectively. Fittings  186 ,  188  further include valves, not shown, operable to place fluid entrances  190 ,  192  into and out of fluid communication with fluid passage  184 . These valves are actuated by levers  194 ,  196 . 
         [0061]    To fill fire extinguisher  20 , valve body  152  is moved into engagement with fitting  36  by actuating pneumatic piston  174  into its extended position, as illustrated in  FIG. 22 . In the extended position illustrated in  FIG. 22 , valve body  152  presses against O-ring  198  to create a seal between valve body  152  and fitting  36 . As valve body  152  is moved into this position, actuation plunger  176  contacts flange  68  of valve  56  and moves flange  68  against the biasing force of spring  72  to unseat valve cover  62  from valve seat  66  and place fill apertures  180  in fluid communication with the interior of fire extinguisher  20 . With tube filling apparatus  150  positioned as illustrated in  FIG. 22 , fire extinguisher  20  can be filled with fire inhibiting substance and pressurized with an inert gas. 
         [0062]    With valve body  152  sealingly engaged with fitting  36  as illustrated in  FIG. 22 , lever  194  can be actuated to place the valve contained within fitting  186  in the open position. In this embodiment, fluid entrance  190  is in fluid communication with a source of fire inhibiting substance. With the valve contained within fitting  186  placed in its open position, fire inhibiting substance will flow through fluid entrance  190 , fitting  186 , fluid passages  184 ,  182 , each of which terminates in an aperture  180 , and valve  56  until it fills the interior of fire extinguisher  20 . Lever  194  is maintained in the open position until the interior of fire extinguisher  20  is sufficiently filled with fire inhibiting substance. In one exemplary embodiment, fire extinguisher  20  is approximately 95% filled with fire inhibiting substance. Thereafter, lever  194  is actuated to place the valve contained within fitting  186  in its closed position and discontinue filling fire extinguisher  20  with fire inhibiting substance. Thereafter, lever  196  is actuated to place the valve within fitting  188  in its open position to allow a source of pressurized inert gas fluidly connected to fluid entrance  192  to flow through fluid entrance  192 , fitting  188 , fluid passages  184 ,  182 , each of which terminates in an aperture  180 , and valve  56  to fill the space remaining in fire extinguisher  20  with inert gas and place the contents of fire extinguisher  20  under pressure. 
         [0063]    In one exemplary embodiment, the contents of fire extinguisher  20  are pressurized to 100 psi. In one exemplary embodiment, pressure gauge  42  is operably positioned on end  26  of tube  22  of fire extinguisher  20  opposite fitting  36 , as illustrated in  FIG. 6 . In such an embodiment, pressure gauge  42  can be utilized to read the pressure within fire extinguisher  20  until sufficient pressure is achieved. When sufficient pressure is achieved, lever  196  can be utilized to close the valve contained within fitting  188  to discontinue adding pressurized inert gas to the interior of fire extinguisher  20 . With fire extinguisher  20  fully filled and pressurized, pneumatic piston  174  can be actuated to the retracted position illustrated in  FIG. 21 . Movement of pneumatic piston  174  from the extended position illustrated in  FIG. 22  to the retracted position illustrated in  FIG. 21  is effected very quickly. With this in mind, spring  72  quickly biases valve  56  into its closed position before more than a minimal amount of fire inhibiting substance and pressurized gas escapes the interior of fire extinguisher  20 . 
         [0064]    Pressure switch  86  and pressure switch connector  74  can now be operatively secured to fitting  36  as illustrated in  FIG. 6  and further described above. Fire extinguisher  20  is now ready for use. 
         [0065]    While the exemplary embodiment described above employs a single, straight tubular enclosure for the fire inhibiting substance, a curved or otherwise nonlinear tubular structure may be utilized. For example, a tube may include a number of bends to facilitate placement in a desired location. 
         [0066]    While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.