Patent Document

CROSS REFERENCE TO RELATED APPLICATION(S) 
   This application is a continuation-in-part of U.S. patent application Ser. No. 10/907,134, filed Mar. 22, 2005. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an onboard apparatus for suppressing a fire involving an automotive vehicle. 
   2. Disclosure Information 
   Police vehicles are subject to increased exposure to collisions, particularly high-speed rear-end collisions, arising from the need for police officers to stop on the shoulders, or even in the traffic lanes, of busy highways. Unfortunately, other motorists are known to collide with police vehicles employed in this manner. These accidents can compromise the fuel system on any vehicle and may cause fires. The present system is designed to suppress the spread of, or potentially, to extinguish such a fire. U.S. Pat. No. 5,590,718, discloses an anti-fire system for vehicles in which a number of fixed nozzles are furnished with a fire extinguishing agent in response to an impact sensor. The system of the ‘718 patent suffers from a problem in that the release of the extinguishing agent is triggered immediately upon receipt of a significant impact. As a result, the anti-fire agent may be expended before the vehicle comes to a halt, with the further result being that a subsequent fire might not be treated by the system. Also, the ‘718 patent uses a valving system which could become clogged and therefore inoperable. U.S. Pat. No. 5,918,681 discloses a system which is similar to that disclosed in the ‘718 patent, inasmuch as the fire extinguishing system does not take into account movement of the vehicle following subjection of the vehicle to an impact. Finally, U.S. Pat. No. 5,762,145 discloses a fuel tank fire protection device including a powdered extinguishing agent panel attached to the fuel tank. In general, powder delivery systems are designed to prevent ignition of fires and are deployed upon impact. As a result, the powder may not be able to follow the post-impact movement of the struck vehicle and may not be able to prevent the delayed ignition or re-ignition of a fire. 
   The present fire suppression system provides significant advantages, as compared with prior art vehicular fire suppression systems. 
   SUMMARY OF THE INVENTION 
   An automotive vehicle according to the present invention includes a vehicle body and at least one reservoir containing a fire suppressant agent. The reservoir containing a fire suppression agent is mounted in proximity to the body, preferably within the body or on an external surface of the body. A sensor system determines whether the vehicle has been subjected to an impact and also whether the vehicle is moving subsequent to such an impact. A distribution system receives the fire suppressant agent from the reservoir and conducts the fire suppressant agent to at least one location about the body, either internally or externally thereto. Finally, a controller operatively connected with the sensor system and the reservoir causes the reservoir to initiate delivery of the fire suppressant agent from the reservoir through the distribution system in the event that a significant impact having a suitable magnitude, duration, and other characteristics, is sensed. 
   According to another aspect of the present invention, the fire suppressant reservoir includes a tank for the suppressant agent and a propellant for establishing pressure within the tank sufficient to deliver suppressant agent from the tank to the distribution system. The propellant may take the form of either a pyrotechnic gas generator, or a canister containing compressed gas, or yet other types of propellants known to those skilled in the art and suggested by this disclosure. 
   According to another aspect of the present invention, the distribution system for the fire suppressant agent includes a number of conduits connected with the reservoir, with the conduits feeding a number of nozzles which may include both fixed and variable geometry nozzles. Release of the fire suppressant agent is governed by the controller, which is operatively connected with at least one accelerometer for sensing vehicle impact and at least one speed sensor for sensing vehicle speed. 
   In addition to the automatic deployment of the fire suppression system provided by the controller, a manually activatable switch is provided for causing the reservoir to initiate delivery of the fire suppressant agent from the reservoir to the distribution system. The manually activatable switch includes a manual pushbutton mounted upon a platform which is responsive not only to manual displacement of the pushbutton, but also to manual displacement of the platform itself. 
   According to another aspect of the present invention, a method for operating a fire suppression system installed in an automotive vehicle includes the steps of sensing an impact upon the vehicle, sensing the vehicle&#39;s speed following the impact, and discharging a fire suppression agent from an onboard reservoir in the event that the vehicle speed crosses a predetermined speed threshold following the sensing of an impact. As a variation of this method, a further step involves discharging the fire suppression agent only if the previous conditions are satisfied, as well as the additional condition that the vehicle is not experiencing acceleration in excess of a predetermined acceleration threshold. 
   The fire suppression agent will be discharged after a predetermined period of time following a significant, or triggering, impact upon the vehicle, regardless of subsequent vehicle speed or acceleration. In this manner, the fire suppression agent will be discharged in the event that the vehicle does not move following an impact. This also permits the system to discharge the suppression agent even if the system&#39;s sensors are damaged during an impact. 
   The sensor system used with the present fire suppression system may be combined with a control system for an occupant restraint airbag or other occupant restraints. 
   According to another aspect of the present invention, a quick connect coupler attaches the fire suppressant feeder conduit to the suppressant reservoir. This facilitates assembly of the present fire suppression system in the underbody environment of a vehicle, thereby reducing assembly cost, while helping to assure integrity of the fire suppression system. 
   According to another aspect of the present invention, the nozzles employed to distribute fire suppression agent discharged from the reservoir may be made from porous material, such as ceramic, or sintered metal. The nozzle may incorporate a closure bulkhead at a first end, and an integral stop abutment at a second end. As compared with a stamped or billet nozzle, a porous metal nozzle produces a more uniform distribution of suppressant agent, and at a lower cost than some competing technologies. 
   According to another aspect of the present invention, a fire suppressant reservoir may be formed as a composite characterized by an outer wall combined with a sealing liner. This construction is generally lighter in weight than conventional all-metal pressure vessels, and offers the advantage of enhanced corrosion resistance. The sealing liner, which may be formed from plastics or metals, or yet other materials, functions to seal leaks by extruding into sealing engagement with the outer wall in the event that a pressure-formed discontinuity opens in the outer wall. The outer wall may be formed from metal or fiber reinforced resin, or other materials known to those skilled in the art and suggested by this disclosure. 
   According to another aspect of the present invention, the gaseous propellant which expels the suppressant from the reservoir may either be the product of a pyrotechnic device, or a gas released from a charged cylinder. This cylinder may be either internal or external to the fire suppressant reservoir. If the gas cylinder is mounted externally, it offers the advantage of permitting a greater volume of fire suppressant to be carried within the reservoir. Alternatively, a smaller reservoir having the same interior volume could be employed with an external gas cylinder in the event that package space is a problem. 
   According to yet another aspect of the present invention, the fire suppressant agent used with this system may be either a single component, such as an aqueous-based preparation, or a binary system in which the primary component is carried within a reservoir, and a secondary component, such as potassium carbonate, carried within the system&#39;s feeder conduits. In this manner, the flow of the primary component through the feeder conduits will cause the discharge of the secondary component into the flowing liquid. Then, both components will mix and be discharged simultaneously. This arrangement permits the use of a binary fire suppression agent without the need for additional storage tanks and propellant devices. 
   According to another aspect of the present invention, in the event that a composite reservoir is specified, it will not generally be possible to weld the initiator conductor conduit, which extends from an upper portion of the system reservoir to a lower portion of the reservoir, to the reservoir itself In such case, an inventive conductor conduit having an axially compliant section and integral upper and lower bonding flanges will allow the conduit to be installed and sealed after the reservoir&#39;s pressure vessel shell has been fabricated. This axially compliant conduit permits the initiator conductor to be protected in substantially the same manner as with a welded steel reservoir, but without the need for welding. 
   According to another aspect of the present invention, a composite reservoir for containing fire suppression agent has a lower closure with a metal or composite plug having a circumferential groove and tension ring for anchoring the outer wall of the composite wall material to the plug. This construction permits a propellant to be mounted to the lower wall of the suppressant reservoir in a manner which resists tearout of the propellant base during deployment of the present system. 
   According to yet another aspect of the present invention, a composite reservoir has a reinforced double concave section. This configuration is necessitated by packaging considerations applicable to the vehicle underbody environment. The double concave section presents a novel design task for fiber-resin composites because the fiber reinforcement in such a section is not placed in tension by the gas force accompanying deployment of the fire suppressant agent. The reinforcements according to the present invention provide the tensile strength needed to withstand this internal gas pressure. In this manner, the volume of suppressant agent may be maximized because the double concave design feature allows the reservoir to be fitted into spaces having rather complex geometry. Such spaces are commonly found in the underbody areas of vehicles. 
   The present fire suppression system represents an advantage over other known systems because it has the capability to suppress a fire without the wheel “shadowing” which would otherwise occur if the flow of fire suppression agent were blocked by one or more wheels when the vehicle is stopped. 
   The present fire suppression system offers the additional advantage of not only automatic actuation, but also manual actuation, so as to allow the vehicle&#39;s operator to discharge the system even when the vehicle has not suffered a significant impact. 
   The present system offers the additional advantage that both variable and fixed geometry nozzles are used to assure adequate dispersion of the fire suppression agent, with the integrity of the system being protected from both road splash and objects thrown up by the vehicle&#39;s wheels during normal operation of the vehicle. Because the variable geometry nozzles are normally tucked up into the vehicle underbody region well above the road surface, these nozzles are protected from damage which would otherwise result from law enforcement maneuvers such as striking curbs and driving offroad. 
   The present system offers the additional advantage that the system operates without the need for an optical or other type of fire sensor which could become obscured, and therefore inoperable, in a vehicle underbody environment. The absence of such sensors allows the present system to begin its activation sequence immediately upon receipt of data indicating a triggering impact. 
   The present system offers the additional advantage that the system operates in the event of impacts which are directed against a vehicle not only longitudinally, but also laterally. 
   The present fire suppression system is designed advantageously to help reduce the risk of injury in high-speed rear impacts. The fire suppression system deploys chemicals designed to suppress the spread of fire or potentially extinguish a fire, thereby providing more time for occupants to escape from a crashed vehicle. 
   Other advantages, as well as objects and features of the present invention will become apparent to the reader of this specification. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a ghost perspective view of an automotive vehicle having a fire suppression system according to the present invention. 
       FIG. 2  is an exploded perspective view of a portion of a fire suppression system according to the present invention. 
       FIG. 3  is a perspective view of a control module used with a system according to the present invention. 
       FIG. 4  is a perspective view of a manually activatable switch used with a fire suppression system according to the present invention. 
       FIG. 5  illustrates a portion of a wiring harness used with the present system. 
       FIG. 6  is a flowchart showing a portion of the logic used to control a system according to the present invention. 
       FIG. 7  is a cutaway perspective view of a fire suppression agent reservoir according to one aspect of the present invention. 
       FIG. 8  is a perspective view of a variable geometry fire suppression agent nozzle according to one aspect of the present invention. 
       FIG. 9  is a block diagram of a fire suppression system and with additional components for occupant restraint according to one aspect of the present invention. 
       FIG. 10  depicts a portion of a distribution system having a porous nozzle, shown in a closed position. 
       FIG. 11  depicts the nozzle of  FIG. 10  in an open position. 
       FIG. 12  illustrates a fire suppressant reservoir and distribution feeder conduit having a quick connect coupler for attaching the feeder conduit to the reservoir. 
       FIG. 13  is a sectional view of the quick connect coupler shown in  FIG. 12 . 
       FIG. 14  is a perspective view of a locking collar incorporated within the coupler of  FIGS. 12 and 13 . 
       FIG. 15   a  illustrates a composite fire suppression agent reservoir according to one aspect of the present invention. 
       FIG. 15   b  illustrates the reservoir of  FIG. 15   a  after a self-healing liner has stopped a pressure-induced fracture in the wall of the reservoir. 
       FIG. 16  illustrates a propellant having an external gas cylinder according to one aspect of the present invention. 
       FIG. 17  illustrates a connector for attaching the gas cylinder of  FIG. 16  to a suppression agent reservoir. 
       FIGS. 18   a ,  18   b ,  18   c , and  18   d  illustrate various structures for introducing a secondary component of a binary fire suppression agent according to one aspect of the present invention. 
       FIG. 19  illustrates an axially compliant initiator conductor conduit useful with a composite fire suppression agent reservoir according to one aspect of the present invention. 
       FIGS. 20   a ,  20   b , and  20   c  illustrate steps for assembling a composite fire suppression agent reservoir having a closure plug made from a different material than the outer wall of the reservoir. 
       FIG. 21  illustrates an assembled composite fire suppression agent reservoir having a closure plug made from a different material than the outer wall of the reservoir. 
       FIG. 22  illustrates a reinforced composite fire suppression agent reservoir having double concave section.  FIG. 22   a  is taken along the line  22   a - 22   a  of  FIG. 22  and shows a concavity in a second direction and the sectional configuration of the reservoir according to an aspect of the present invention. 
       FIG. 23  is a sectional view of a double concave section of the reservoir depicted in  FIG. 22 . 
       FIGS. 24   a  and  24   b  illustrate integral ribs formed externally and internally, respectively, as part of the composite reservoir of  FIG. 22 . 
       FIGS. 25   a  and  25   b  illustrate preformed ribs bonded externally and internally, respectively, to the outer wall of the composite reservoir of  FIG. 22 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   As shown in  FIG. 1 , vehicle  10  has a passenger airbag restraint,  48 , and a driver&#39;s airbag restraint,  50 , mounted adjacent steering wheel  52 . A fire suppression system includes controller  66  which is mounted upon floor pan  68  of vehicle  10 , and reservoirs  18  which are mounted under floor pan  68  in the so-called kick-up area adjoining the rear axle of vehicle  10 . Those skilled in the art will appreciate in view of this disclosure that additional passenger restraint devices, such as seat belt pretensioners and side airbags, may be installed in a vehicle and controlled at least in part by, or in conjunction with, controller  66 . 
     FIG. 1  shows not only reservoirs  18  but also a portion of right and left side fire suppression conduits  28 , as well as fixed geometry nozzles  30  and variable geometry nozzles  36 . As seen in  FIG. 1 , variable geometry nozzles  36  project downwardly to allow fire suppression agent to be expelled from reservoirs  18  and placed at a low angle to the ground surface the vehicle is operating upon. This mode of operation is possible because variable geometry nozzles  36  are, as shown in  FIG. 2 , telescopingly extensible. This telescoping feature, which is shown in greater detail in  FIG. 8 , is produced by a sliding spray head,  40 , which is slidingly engaged with conduit  28  such that gas pressure within conduit  28  forces spray head  40  downwardly into its extended position, causing fire suppression agent  22  to be discharged through a number of holes  42  formed in spray head  40 . As shown in  FIG. 2 , at least two variable geometry nozzles  36  may be employed with single reservoir  18 , along with at least two fixed nozzles  30  which are spray bars each having a number of orifices  34 . While in their normally closed state, variable geometry nozzles  36  are liquid-tight by virtue of seals  46 , which are interposed between an end of each of spray heads  40  and the corresponding ends of conduits  28 . In a preferred embodiment, seals  46  comprise elastomeric boots attached to an outer surface of conduit  28 . Seals  46  are simply sheared by the deploying spray head  40  when the present system is discharged. Fixed nozzles  30  are also rendered liquid-tight by covers  44 , which are simply blown off when the present system is discharged. The sealing of nozzles  30  and  36  is important, because this prevents the ingress of road splash, which could block the system in sub-freezing weather or cause corrosion or blockage due to mud or other foreign matter. 
   Additional details of reservoir  18  are shown in  FIG. 7 . Tank  90  contains approximately 1.5 L of fire suppression agent  22 , and a propellant  92 . Propellant  92  includes two squibs (not shown) which are activated simultaneously by controller  66  via lines  91  so as to release a large amount of gas, forcing fire suppressant agent  22  from tank  90  and into distribution system  26 , including conduit  28  and the various fixed and variable geometry nozzles. A preferred propellant, marketed by Primex Aerospace Company as model FS01-40, is a mixture including aminotetrazole, strontium nitrate, and magnesium carbonate. This is described in U.S. Pat. No. 6,702,033, which is hereby incorporated by reference into this specification. 
   Those skilled in the art will appreciate in view of this disclosure that other types of propellants could be used in the present system, such as compressed gas canisters and other types of pyrotechnic and chemical devices capable of creating a gas pressure force in a vanishingly small amount of time. Moreover, fire suppressant agent  22 , which preferably includes a water-based solution with hydrocarbon surfactants, fluorosurfactants, and organic and inorganic salts sold under the trade name LVS Wet Chemical Agent® by Ansul Incorporated, could comprise other types of agents such as powders or other liquids, or yet other agents known to those skilled in the art and suggested by this disclosure. If two reservoirs  18  are employed with a vehicle, as is shown in  FIG. 1 , all four squibs will be deployed simultaneously. 
     FIG. 4  shows manually activatable switch  54  for use with the present system. As shown in  FIG. 1 , switch  54  may be advantageously located on the headliner of vehicle  10  between the sun visors, or at any other convenient position. To use this switch  54 , hinged clear cover  56  is first opened by pressing on cover  56 . Thereafter, the fire suppression system may be triggered by manually pressing pushbutton  58 . If the vehicle occupants are not disposed to release cover  56 , the system may be triggered by merely sharply depressing cover  56 , thereby closing contacts (not shown) contained within platform  60 . 
   Because the present system is intended for use when the vehicle has received a severe impact, controller  66 , which is shown in  FIG. 3 , contains a redundant power reserve or supply, which allows operation of the fire suppression system for about nine seconds, even if controller  66  becomes isolated from the vehicle&#39;s electrical power supply. Wiring harness  80 , as shown in  FIG. 5 , is armored, and has a para-aramid fiber inner sheath,  82 , of about 2 mm in thickness, which helps to shield the conductors within harness  80  from abrasion and cutting during a vehicle impact event. This para-aramid fiber is sold under the trade name KEVLAR® by the DuPont company. This armoring helps to assure that communication between controller  66  and reservoirs  18  remains in effect during an impact event. Post-impact communications are further aided by redundancy in the control system. Specifically, four independent sets of primary conductors,  79   a - d,  extend from controller  66  to reservoirs  18  protected by sheath  82 . Moreover, an H-conductor, shown at  81  in  FIG. 5 , extends between reservoirs  18 . Thus, if one or both of the primary conductors  79   a - b,  or  79   c - d,  extending to one of reservoirs  18  should become severed, H-conductor  81  will be available to carry the initiation signal from the undamaged lines to both of reservoirs  18 . 
   As noted above, an important feature of the present invention resides in the fact that the control parameters include not only vehicle impact, as measured by an accelerometer such as that shown at  70  in  FIG. 9 , but also vehicle speed, as measured by means of speed sensors  74 , also shown in  FIG. 9 . Speed sensors  74  may advantageously be existing sensors used with an anti-lock braking system or vehicle stability system. Alternatively, speed sensors  74  could comprise a global positioning sensor or a radar or optically based ground-sensing system. Accelerometer  70 , as noted above, could be used with a conventional occupant restraint airbag system, thereby maximizing use of existing systems within the vehicle. Advantageously, accelerometer  70  may be an amalgam of two or more accelerometers having differing sensing ranges. Such arrangements are known to those skilled in the art and suggested by this disclosure. At least a portion of the various sensors could either be integrated in controller  66  or distributed about vehicle  10 . 
     FIG. 6  shows a sequence which is used according to one aspect of the present invention for activating a release of fire suppressant agent. 
   Beginning at block  100 , controller  66  performs various diagnostics on the present system, which are similar to the diagnostics currently employed with supplemental restraint systems. For example, various sensor values and system resistances will be evaluated on a continuous basis. Controller  66  periodically moves to block  102 , wherein the control algorithm will be shifted from a standby mode to an awake mode in the event that a vehicle acceleration, or, in other words, an impact, having a magnitude in excess of a relatively low threshold is sensed by accelerometer  70 . Also, at block  102  a backup timer will be started. If the algorithm is awakened at block  102 , controller  66  disables manually activatable switch  54  at block  104  for a predetermined amount of time, say  150  milliseconds. This serves to prevent switch  54  from inadvertently causing an out-of-sequence release of fire suppression agent. Note that at block  104 , a decision has not yet been made to deploy fire suppression agent  22  as a result of a significant impact. 
   At block  106 , controller  66  uses output from accelerometer  70  to determine whether there has been an impact upon vehicle  10  having a severity is in excess of a predetermined threshold impact value. Such an impact may be termed a significant, or “trigger”, impact. If an impact is less severe than a trigger impact, the answer at block  106  is “no”, and controller  66  will move to block  105 , wherein an inquiry is made regarding the continuing nature of the impact event. If the event has ended, the routine moves to block  100  and continues with the diagnostics. If the event is proceeding, the answer at block  105  is “yes”, and the routine loops to block  106 . 
   If a significant impact is sensed by the sensor system including accelerometer  70  and controller  66 , the answer at block  106  will be “yes.” If such is the case, controller  66  moves to block  108  wherein the status of a backup timer is checked. This timer was started at block  102 . 
   Once the timer within controller  66  has counted up to a predetermined, calibratable time on the order of, for example, 5-6 seconds, controller  66  will cause propellant  92  to initiate delivery of fire suppressant agent  22 , provided the agent was not released earlier. Propellant  92  is activated by firing an electrical squib so as to initiate combustion of a pyrotechnic charge. Alternatively, a squib may be used to pierce, or otherwise breach, a pressure vessel. Those skilled in the art will appreciate in view of this disclosure that several additional means are available for generating the gas required to expel fire suppressant agent  22  from tank  90 . Such detail is beyond the scope of this invention. An important redundancy is supplied by having two squibs located within each of tanks  90 . All four squibs are energized simultaneously. 
   The velocity of the vehicle  10  is measured at block  110  using speed sensors  74 , and compared with a low velocity threshold. In essence, controller  66  processes the signals from the various wheel speed sensors  74  by entering the greatest absolute value of the several wheel speeds into a register. This register contains both a weighted count of the number of samples below a threshold and a count of the number of samples above the threshold. When the register value crosses a threshold value, the answer at block  110  becomes “yes”. In general, the present inventors have determined that it is desirable to deploy fire suppression agent  22  prior to the vehicle coming to a stop. For example, fire suppression agent  22  could be dispersed when the vehicle slows below about 15 kph. 
   At block  112 , controller  66  enters a measured vehicle acceleration value into a second register. Thereafter, once the acceleration register value decays below a predetermined low g threshold, the answer becomes “yes” at block  112 , and the routine moves to block  114  and releases fire suppressant agent  22 . In essence, a sensor fusion method combines all available sensor information to verify that the vehicle is approaching a halt. The routine ends at block  116 . Because the present fire suppression system uses all of the available fire suppression agent  22  in a single deployment, the system cannot be redeployed without replacing at least reservoirs  18 . 
     FIG. 6  does not include the activation of occupant restraints  48  and  50 , it being understood that known control sequences, having much different timing constraints, may be employed for this purpose. In point of contrast, the low velocity threshold allows the present system to deliver the fire suppression agent while the vehicle is still moving, albeit at a very low velocity. This prevents the rear wheels of the vehicle from shadowing, or blocking dispersion of fire suppressant agent  22 . Also, in many cases, a vehicular fire may not become well-established until the vehicle comes to a halt. 
     FIGS. 10 and 11  illustrate an additional nozzle embodiment according to another aspect of the present invention. Rather than having a stamped and welded construction, nozzle  232  is porous. The porous material may be either ceramic, or sintered metal, or other types of porous materials known to those skilled in the art and suggested by this disclosure. The material may be cast, or pressed, or extruded, or formed by any other suitable method. 
     FIG. 10  shows nozzle body  236  in its stowed position, and  FIG. 11  shows nozzle body  236  in its telescopically deployed position, which results from the buildup of fluid pressure within feeder conduit  28 . While in the stowed position of  FIG. 10 , nozzle body  236  is retained within feeder conduit  28  by frangible sealing disc  252 , which functions as a stowage seal by sealing against annular surface  258  formed in the end of feeder conduit  28 . Frangible sealing disc  252  is maintained in contact with annular surface  258  by means of external seal retainer  260 , which is attached to the outer end of feeder conduit  28 . 
   Frangible sealing disc  252  serves not only to prevent the ingress of contamination into feeder conduit  28  when nozzle body  236  is in its stowed position, but also prevents the escape of fire suppression agent from the closed, or bulkhead end,  244  of nozzle body  236 . This feature may be used to tune or adjust the distribution of fire suppression agent from nozzle  232 . 
   When nozzle body  236  is projecting telescopically from feeder conduit  28 , integral stop abutment and fluid seal  248  cooperates with internal stop abutment  256  formed at the end of conduit  28  to both seal the joint between nozzle body  236  and feeder conduit  28 , and to prevent nozzle body  236  from separating from feeder conduit  28  in response to the fluid pressure of the flowing fire suppressant agent. 
     FIGS. 12 ,  13 , and  14  illustrate another aspect of the present invention. A quick connect coupler attaches the fire suppressant feeder conduit to the suppressant reservoir. This facilitates assembly of the present fire suppression system in the underbody environment of a vehicle, thereby reducing assembly cost, while helping to assure integrity of the fire suppression system. Reservoir  18  is equipped with a spud,  200 , having external threads,  204 . Threads  204  are interrupted. The importance of this feature will be explained below. Feeder conduit  28  has an annular retention flange,  208 , which abuts collar  216  when feeder conduit  28  is attached to reservoir  18 . 
   A section of a fully assembled joint consisting of feeder conduit  28 , spud  200 , collar  216 , and o-ring seal  212  is shown fully assembled in  FIG. 13 . Threads  220 , which are formed internally on collar  216 , cooperate with threads  204  formed on spud  200  to lock the various components together. O-ring seal is compressed between bore  202  of spud  200  and an outer surface of conduit  28 , so as to provide a leak-tight seal between spud  200  and conduit  28 . The joint of  FIG. 13  is made up by inserting conduit  28  into spud bore  202  until retention flange  208  abuts spud  200 . Then, collar  216  is brought into contact with spud  200  and collar  216  is rotated to lock threads  204  and  220 . Because each of threads  204  and  220  are interrupted—i.e., they do not circumscribe the bases to which they are attached, collar  216  may be fully driven and seated upon spud  200  with less than one full revolution. This greatly facilitates assembly of the present system under a vehicle body. 
     FIG. 14  illustrates an anti-rotation feature provided by axially displaceable pints  224 . When collar  216  has been fully rotated upon spud  200 , pins  224  will be extended by compression springs (one spring,  228  being shown). Once pins  224  have extended, rotation of collar  216  in a direction permitting detachment of collar  216  from spud  200  will be prevented because each of pins  224  will abut one of threads  204  formed on spud  200 . 
     FIGS. 15   a  and  15   b  illustrate a fire suppressant reservoir,  264 , formed as a composite characterized by a pressure vessel having an outer wall,  268 , combined with a sealing liner,  272 . Outer wall  268  may be formed from metal or fiber reinforced resin, or other metallic or nonmetallic materials or composites known to those skilled in the art and suggested by this disclosure. 
   Liner  272  is said to be a dynamic reservoir seal because liner  272  is sufficiently extrudable in response to fluid pressure produced by the propellant device that liner  272  will extrude or squeeze directly into discontinuities caused by the high operating pressure of the present fire suppression system. This extrusion will seal outer wall  268 , preventing an excessive loss of the fire suppressant agent. In  FIG. 15   b , portion  280  of liner  272  is shown as having extruded through discontinuity  276 . As shown in  FIG. 15   b , portion  280  is in sealing engagement with outer wall  268 . 
   Sealing liner  272  may be formed from plastics or metals, elastomers, composites, or yet other materials known to those skilled in the art and suggested by this disclosure. In any event liner  272  is selected to provide the pressure-driven extrusion characteristic needed to seal outer wall  268  if a high pressure leak develops in reservoir  18 . 
     FIG. 16  shows a second type of propellant useful for practicing the present invention. Compressed gas cylinder  284  is pre-charged with a high pressure gas, such as nitrogen. Valve  288 , which is operatively connected with controller  66 , is opened when needed to permit gas to flow from cylinder  284  and through high pressure conduit  292 , thereby initiating discharge of the fire suppressant agent from reservoir  18 . As but one alternative to the arrangement shown in  FIG. 16 , gas cylinder  284  could be located within reservoir  18  in the manner shown in  FIGS. 15   a  and  15   b , albeit at the expense of volume for the fire suppressant agent. The present compressed gas propellant provides a supply-chain advantage, inasmuch as non-pyrotechnic propellants are subject to less stringent shipping restrictions than are pyrotechnic devices. 
     FIG. 17  illustrates a system for connecting high pressure conduit  292  with reservoir  18 . A dome,  298  is provided in an upper surface of reservoir  18 . Dome  298  has a port,  296 , through which conduit  292  extends into the interior of reservoir  18 . As conduit  292  is inserted, it displaces valve disc  308  and spring  312 . Conduit  292  is retained within port  296  by means of retainer  300 , which passes through holes (not shown) formed dome  298 . Once conduit  292  has been installed, high pressure gas may flow into reservoir  18  through a series of exit orifices  304  formed in conduit  292 . 
   According to another aspect of the present invention, a fire suppressant agent used with this system may be either a single component, generally an aqueous-based preparation, or a binary system in which a primary component is carried within a first, or primary, reservoir, and a secondary component, such as potassium carbonate, is carried within a secondary reservoir accessible to the fire suppression system&#39;s feeder conduits. Passage of the primary component through a feeder conduit will cause the secondary component to be released such that the primary component and the secondary component will be combined before being discharged from the distribution nozzles. In essence, the purpose of the secondary component delivery system is to place the secondary component into a stream of primary component flowing within the present distribution system. If the secondary delivery system is housed within feeder conduit  28 , the need for an additional discrete reservoir for the secondary component may be avoided. 
     FIGS. 18   a - 18   d  illustrate several embodiments of secondary reservoirs.  FIG. 18   a  shows a secondary reservoir defined by venturi tube  316 , which establishes an annular-shaped storage chamber,  320  within feeder conduit  28 . A number orifices,  324  are formed at the throat,  322 , of venturi tube  316 , such that primary component flowing through venturi tube  316  will cause secondary component  318  to be drawn through orifices  324  and aspirated into the flowing primary component stream. In the embodiment of  FIG. 18   a , secondary component  318  could be in either a liquid or a powder state. 
     FIG. 18   b  illustrates a secondary reservoir having a generally cylindrical housing,  328 , which is filled with secondary component  318  in either a powder or gelatinous state. As with the embodiment of  FIG. 18   a , housing  328  is located within feeder conduit  28 . Pressure-responsive piston  332  is displaced by the pressure of the flowing primary component, and, as piston  332  moves down the bore of cylindrical housing  328 , secondary component  318  will be expelled through discharge orifices  336 . 
     FIG. 18   c  illustrates a secondary reservoir having a generally cylindrical housing,  340 , enclosing a quantity of secondary component  318 , preferably in either a gelatinous or powdered state. When the primary component is flowing through feeder conduit  28 , turbine  346 , as well as shaft  352  and shredder blade  356 , will rotate in the manner of a windmill. As a result, shredder blade  356  will cooperate with shredder plate  360  to pulverize secondary component  318 , which is forced through shredder plate  360  by piston  344  and compression spring  348 . 
     FIG. 18   d  illustrates a sacrificial secondary reservoir having a hollow cylindrical plug or lining,  364  made from solid secondary component, such as potassium carbonate. Lining  364  has a number of integral internal splines,  368 . Lining  364  is formulated and processed so that flowing primary component will cause lining  364  to be eroded and entrained in the flowing primary component. 
   With a composite fire suppressant reservoir, it is generally not possible to weld the initiator conductor conduit extending from an upper portion of the reservoir to a lower portion of the reservoir, to the reservoir itself. However, with the axially compliant conduit illustrated in  FIG. 19 , this problem is avoided, while permitting the initiator conductor to be protected against damage. Conduit  384  is inserted into reservoir  18  after the pressure vessel shell, in this case, the outer wall of reservoir  18 , has been fabricated. This process begins with insertion of conduit  384  into the interior of reservoir  18  through assembly port  378 . Installation of conduit  384  continues with placement of the conduit&#39;s upper end,  384   a , into an upper conduit port formed in wall  18   a . Then, axial compliance section  388  is compressed sufficiently to allow lower end  384   b  of conduit  384  to be inserted to a lower conduit port located in lower wall  18   b . Conduit  384  is then permitted to expand axially. Then, an initiator conductor or wire,  380  may be inserted into conduit  384 . Finally, propellant device  372 , which is attached to base  382 , may be mounted within port  378 . 
   Conduit  384  has an upset section,  396 , adjacent to each of its upper and lower ends,  384   a  and  384   b , and these upset sections  396  lock into bonding flanges  392 , which are adhesively sealed to reservoir walls  18   a  and  18   b.    
     FIGS. 20   a - 20   c  illustrate a method for assembling a composite fire suppression agent reservoir having a closure plug either made from a different material than the outer wall of the reservoir, or from a material which is not thermally weldable to the outer wall.  FIG. 20   a  shows a preform having outer wall  400 , and inner reinforcement  404 . Closure plug  406  has a circumferential groove,  406   a , which allows tension band  410  purchase to bind outer wall  400  and inner reinforcement  404  to closure plug  406 . Plug  406  may be solvent welded, or bonded with various adhesives known to those skilled in the art, to outer wall  400  and inner reinforcement  404 . 
   The embodiment of  FIGS. 20   a - 20   c  is especially useful for practicing a variant of the present invention in which an external propellant is employed. On the other hand, the embodiment of  FIG. 21  shows a combined structure in which closure plug  412  is also employed as a base for internally located propellant  372 . As before, plug  412  may be attached to the composite wall of reservoir  18  both mechanically by means of tension band  410  and/or by chemical bonding or friction welding. 
     FIGS. 22-25   b  show a reservoir construction based upon a composite wall,  424 , which may be formed from fiber or metal reinforced resin, or other composites known to those skilled in the art and suggested by this disclosure. The reservoir shown in  FIG. 22 , which is ideally constructed of composite material  424 , employs at least one double concave section to promote the adaptability of the reservoir for installation into spaces having irregular geometry. Accordingly, reservoir  416  is shown with double concave section  420 , which is generally bowl-shaped.  FIG. 22  shows a first concavity, following the curve of arrow “A,” and  FIG. 22   a  shows a second concavity following the curve of arrow “B.” Of course, both concavities originate at the outside of reservoir  416 . Section  420  is reinforced by metallic doubler  428 , which may be insert molded to the interior surface of double concave section  420 .  FIG. 24   a  illustrates an embodiment in which mold  426  has a groove,  427 , which forms an integral rib,  432 , on an outer portion of double concave section  420  during the process of molding reservoir  416 .  FIG. 24   b  illustrates a similar embodiment in which rib  432  is formed on an inner surface of section  420 . In the interest of clarity, mold  426  is not shown in  FIG. 24   b , or  FIGS. 25   a  and  25   b . 
   In the embodiments of  FIGS. 25   a  and  25   b , preformed ribs are insert molded to double concave section  420 . More specifically, in  FIG. 25   a , rib  436  is shown as having been insert molded to an outer portion of section  420 , and in  FIG. 25   b , rib  436  is shown as having been molded or bonded to an inner surface of section  420 . Those skilled in the art will appreciate in view of this disclosure that insert molding may be accomplished by fabricating a preform, in this case ribs  436 , which are placed into the mold  426  prior to injecting and curing the resin. Ribs  436  may be fabricated from either fiber-reinforced resin, or other metallic or non-metallic materials or composites known to those skilled in the art and suggested by this disclosure. 
   Although the present invention has been described in connection with particular embodiments thereof, it is to be understood that various modifications, alterations, and adaptations may be made by those skilled in the art without departing from the spirit and scope of the invention set forth in the following claims.

Technology Category: 1