Automotive fire suppression system with a reinforced, double concave composite reservoir

An onboard fire suppression system for a vehicle has at least one composite reservoir containing a fire suppressant agent. The reservoir includes a pressure vessel formed from fiber-composite material and having at least one double concave section. At least one reinforcement is applied to the pressure vessel in the location of the double concave section. This construction permits the pressure vessel to have a shape conforming with the irregular spaces commonly found in the underbody areas of vehicles.

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'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'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'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'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'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'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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown inFIG. 1, vehicle10has a passenger airbag restraint,48, and a driver's airbag restraint,50, mounted adjacent steering wheel52. A fire suppression system includes controller66which is mounted upon floor pan68of vehicle10, and reservoirs18which are mounted under floor pan68in the so-called kick-up area adjoining the rear axle of vehicle10. 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, controller66.

FIG. 1shows not only reservoirs18but also a portion of right and left side fire suppression conduits28, as well as fixed geometry nozzles30and variable geometry nozzles36. As seen inFIG. 1, variable geometry nozzles36project downwardly to allow fire suppression agent to be expelled from reservoirs18and placed at a low angle to the ground surface the vehicle is operating upon. This mode of operation is possible because variable geometry nozzles36are, as shown inFIG. 2, telescopingly extensible. This telescoping feature, which is shown in greater detail inFIG. 8, is produced by a sliding spray head,40, which is slidingly engaged with conduit28such that gas pressure within conduit28forces spray head40downwardly into its extended position, causing fire suppression agent22to be discharged through a number of holes42formed in spray head40. As shown inFIG. 2, at least two variable geometry nozzles36may be employed with single reservoir18, along with at least two fixed nozzles30which are spray bars each having a number of orifices34. While in their normally closed state, variable geometry nozzles36are liquid-tight by virtue of seals46, which are interposed between an end of each of spray heads40and the corresponding ends of conduits28. In a preferred embodiment, seals46comprise elastomeric boots attached to an outer surface of conduit28. Seals46are simply sheared by the deploying spray head40when the present system is discharged. Fixed nozzles30are also rendered liquid-tight by covers44, which are simply blown off when the present system is discharged. The sealing of nozzles30and36is 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 reservoir18are shown inFIG. 7. Tank90contains approximately 1.5 L of fire suppression agent22, and a propellant92. Propellant92includes two squibs (not shown) which are activated simultaneously by controller66via lines91so as to release a large amount of gas, forcing fire suppressant agent22from tank90and into distribution system26, including conduit28and 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 agent22, 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 reservoirs18are employed with a vehicle, as is shown inFIG. 1, all four squibs will be deployed simultaneously.

FIG. 4shows manually activatable switch54for use with the present system. As shown inFIG. 1, switch54may be advantageously located on the headliner of vehicle10between the sun visors, or at any other convenient position. To use this switch54, hinged clear cover56is first opened by pressing on cover56. Thereafter, the fire suppression system may be triggered by manually pressing pushbutton58. If the vehicle occupants are not disposed to release cover56, the system may be triggered by merely sharply depressing cover56, thereby closing contacts (not shown) contained within platform60.

Because the present system is intended for use when the vehicle has received a severe impact, controller66, which is shown inFIG. 3, contains a redundant power reserve or supply, which allows operation of the fire suppression system for about nine seconds, even if controller66becomes isolated from the vehicle's electrical power supply. Wiring harness80, as shown inFIG. 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 harness80from 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 controller66and reservoirs18remains 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,79a-d,extend from controller66to reservoirs18protected by sheath82. Moreover, an H-conductor, shown at81inFIG. 5, extends between reservoirs18. Thus, if one or both of the primary conductors79a-b,or79c-d,extending to one of reservoirs18should become severed, H-conductor81will be available to carry the initiation signal from the undamaged lines to both of reservoirs18.

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 at70inFIG. 9, but also vehicle speed, as measured by means of speed sensors74, also shown inFIG. 9. Speed sensors74may advantageously be existing sensors used with an anti-lock braking system or vehicle stability system. Alternatively, speed sensors74could comprise a global positioning sensor or a radar or optically based ground-sensing system. Accelerometer70, as noted above, could be used with a conventional occupant restraint airbag system, thereby maximizing use of existing systems within the vehicle. Advantageously, accelerometer70may 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 controller66or distributed about vehicle10.

FIG. 6shows a sequence which is used according to one aspect of the present invention for activating a release of fire suppressant agent.

Beginning at block100, controller66performs 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. Controller66periodically moves to block102, 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 accelerometer70. Also, at block102a backup timer will be started. If the algorithm is awakened at block102, controller66disables manually activatable switch54at block104for a predetermined amount of time, say150milliseconds. This serves to prevent switch54from inadvertently causing an out-of-sequence release of fire suppression agent. Note that at block104, a decision has not yet been made to deploy fire suppression agent22as a result of a significant impact.

At block106, controller66uses output from accelerometer70to determine whether there has been an impact upon vehicle10having 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 block106is “no”, and controller66will move to block105, wherein an inquiry is made regarding the continuing nature of the impact event. If the event has ended, the routine moves to block100and continues with the diagnostics. If the event is proceeding, the answer at block105is “yes”, and the routine loops to block106.

If a significant impact is sensed by the sensor system including accelerometer70and controller66, the answer at block106will be “yes.” If such is the case, controller66moves to block108wherein the status of a backup timer is checked. This timer was started at block102.

Once the timer within controller66has counted up to a predetermined, calibratable time on the order of, for example, 5-6 seconds, controller66will cause propellant92to initiate delivery of fire suppressant agent22, provided the agent was not released earlier. Propellant92is 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 agent22from tank90. Such detail is beyond the scope of this invention. An important redundancy is supplied by having two squibs located within each of tanks90. All four squibs are energized simultaneously.

The velocity of the vehicle10is measured at block110using speed sensors74, and compared with a low velocity threshold. In essence, controller66processes the signals from the various wheel speed sensors74by 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 block110becomes “yes”. In general, the present inventors have determined that it is desirable to deploy fire suppression agent22prior to the vehicle coming to a stop. For example, fire suppression agent22could be dispersed when the vehicle slows below about 15 kph.

At block112, controller66enters 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 block112, and the routine moves to block114and releases fire suppressant agent22. In essence, a sensor fusion method combines all available sensor information to verify that the vehicle is approaching a halt. The routine ends at block116. Because the present fire suppression system uses all of the available fire suppression agent22in a single deployment, the system cannot be redeployed without replacing at least reservoirs18.

FIG. 6does not include the activation of occupant restraints48and50, 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 agent22. Also, in many cases, a vehicular fire may not become well-established until the vehicle comes to a halt.

FIGS. 10 and 11illustrate an additional nozzle embodiment according to another aspect of the present invention. Rather than having a stamped and welded construction, nozzle232is 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. 10shows nozzle body236in its stowed position, andFIG. 11shows nozzle body236in its telescopically deployed position, which results from the buildup of fluid pressure within feeder conduit28. While in the stowed position ofFIG. 10, nozzle body236is retained within feeder conduit28by frangible sealing disc252, which functions as a stowage seal by sealing against annular surface258formed in the end of feeder conduit28. Frangible sealing disc252is maintained in contact with annular surface258by means of external seal retainer260, which is attached to the outer end of feeder conduit28.

Frangible sealing disc252serves not only to prevent the ingress of contamination into feeder conduit28when nozzle body236is in its stowed position, but also prevents the escape of fire suppression agent from the closed, or bulkhead end,244of nozzle body236. This feature may be used to tune or adjust the distribution of fire suppression agent from nozzle232.

When nozzle body236is projecting telescopically from feeder conduit28, integral stop abutment and fluid seal248cooperates with internal stop abutment256formed at the end of conduit28to both seal the joint between nozzle body236and feeder conduit28, and to prevent nozzle body236from separating from feeder conduit28in response to the fluid pressure of the flowing fire suppressant agent.

FIGS. 12,13, and14illustrate 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. Reservoir18is equipped with a spud,200, having external threads,204. Threads204are interrupted. The importance of this feature will be explained below. Feeder conduit28has an annular retention flange,208, which abuts collar216when feeder conduit28is attached to reservoir18.

A section of a fully assembled joint consisting of feeder conduit28, spud200, collar216, and o-ring seal212is shown fully assembled inFIG. 13. Threads220, which are formed internally on collar216, cooperate with threads204formed on spud200to lock the various components together. O-ring seal is compressed between bore202of spud200and an outer surface of conduit28, so as to provide a leak-tight seal between spud200and conduit28. The joint ofFIG. 13is made up by inserting conduit28into spud bore202until retention flange208abuts spud200. Then, collar216is brought into contact with spud200and collar216is rotated to lock threads204and220. Because each of threads204and220are interrupted—i.e., they do not circumscribe the bases to which they are attached, collar216may be fully driven and seated upon spud200with less than one full revolution. This greatly facilitates assembly of the present system under a vehicle body.

FIG. 14illustrates an anti-rotation feature provided by axially displaceable pints224. When collar216has been fully rotated upon spud200, pins224will be extended by compression springs (one spring,228being shown). Once pins224have extended, rotation of collar216in a direction permitting detachment of collar216from spud200will be prevented because each of pins224will abut one of threads204formed on spud200.

FIGS. 15aand15billustrate 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 wall268may 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.

Liner272is said to be a dynamic reservoir seal because liner272is sufficiently extrudable in response to fluid pressure produced by the propellant device that liner272will extrude or squeeze directly into discontinuities caused by the high operating pressure of the present fire suppression system. This extrusion will seal outer wall268, preventing an excessive loss of the fire suppressant agent. InFIG. 15b, portion280of liner272is shown as having extruded through discontinuity276. As shown inFIG. 15b, portion280is in sealing engagement with outer wall268.

Sealing liner272may 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 liner272is selected to provide the pressure-driven extrusion characteristic needed to seal outer wall268if a high pressure leak develops in reservoir18.

FIG. 16shows a second type of propellant useful for practicing the present invention. Compressed gas cylinder284is pre-charged with a high pressure gas, such as nitrogen. Valve288, which is operatively connected with controller66, is opened when needed to permit gas to flow from cylinder284and through high pressure conduit292, thereby initiating discharge of the fire suppressant agent from reservoir18. As but one alternative to the arrangement shown inFIG. 16, gas cylinder284could be located within reservoir18in the manner shown inFIGS. 15aand15b, 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. 17illustrates a system for connecting high pressure conduit292with reservoir18. A dome,298is provided in an upper surface of reservoir18. Dome298has a port,296, through which conduit292extends into the interior of reservoir18. As conduit292is inserted, it displaces valve disc308and spring312. Conduit292is retained within port296by means of retainer300, which passes through holes (not shown) formed dome298. Once conduit292has been installed, high pressure gas may flow into reservoir18through a series of exit orifices304formed in conduit292.

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'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 conduit28, the need for an additional discrete reservoir for the secondary component may be avoided.

FIGS. 18a-18dillustrate several embodiments of secondary reservoirs.FIG. 18ashows a secondary reservoir defined by venturi tube316, which establishes an annular-shaped storage chamber,320within feeder conduit28. A number orifices,324are formed at the throat,322, of venturi tube316, such that primary component flowing through venturi tube316will cause secondary component318to be drawn through orifices324and aspirated into the flowing primary component stream. In the embodiment ofFIG. 18a, secondary component318could be in either a liquid or a powder state.

FIG. 18billustrates a secondary reservoir having a generally cylindrical housing,328, which is filled with secondary component318in either a powder or gelatinous state. As with the embodiment ofFIG. 18a, housing328is located within feeder conduit28. Pressure-responsive piston332is displaced by the pressure of the flowing primary component, and, as piston332moves down the bore of cylindrical housing328, secondary component318will be expelled through discharge orifices336.

FIG. 18cillustrates a secondary reservoir having a generally cylindrical housing,340, enclosing a quantity of secondary component318, preferably in either a gelatinous or powdered state. When the primary component is flowing through feeder conduit28, turbine346, as well as shaft352and shredder blade356, will rotate in the manner of a windmill. As a result, shredder blade356will cooperate with shredder plate360to pulverize secondary component318, which is forced through shredder plate360by piston344and compression spring348.

FIG. 18dillustrates a sacrificial secondary reservoir having a hollow cylindrical plug or lining,364made from solid secondary component, such as potassium carbonate. Lining364has a number of integral internal splines,368. Lining364is formulated and processed so that flowing primary component will cause lining364to 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 inFIG. 19, this problem is avoided, while permitting the initiator conductor to be protected against damage. Conduit384is inserted into reservoir18after the pressure vessel shell, in this case, the outer wall of reservoir18, has been fabricated. This process begins with insertion of conduit384into the interior of reservoir18through assembly port378. Installation of conduit384continues with placement of the conduit's upper end,384a, into an upper conduit port formed in wall18a. Then, axial compliance section388is compressed sufficiently to allow lower end384bof conduit384to be inserted to a lower conduit port located in lower wall18b. Conduit384is then permitted to expand axially. Then, an initiator conductor or wire,380may be inserted into conduit384. Finally, propellant device372, which is attached to base382, may be mounted within port378.

Conduit384has an upset section,396, adjacent to each of its upper and lower ends,384aand384b, and these upset sections396lock into bonding flanges392, which are adhesively sealed to reservoir walls18aand18b.

FIGS. 20a-20cillustrate 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. 20ashows a preform having outer wall400, and inner reinforcement404. Closure plug406has a circumferential groove,406a, which allows tension band410purchase to bind outer wall400and inner reinforcement404to closure plug406. Plug406may be solvent welded, or bonded with various adhesives known to those skilled in the art, to outer wall400and inner reinforcement404.

The embodiment ofFIGS. 20a-20cis especially useful for practicing a variant of the present invention in which an external propellant is employed. On the other hand, the embodiment ofFIG. 21shows a combined structure in which closure plug412is also employed as a base for internally located propellant372. As before, plug412may be attached to the composite wall of reservoir18both mechanically by means of tension band410and/or by chemical bonding or friction welding.

FIGS. 22-25bshow 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 inFIG. 22, which is ideally constructed of composite material424, employs at least one double concave section to promote the adaptability of the reservoir for installation into spaces having irregular geometry. Accordingly, reservoir416is shown with double concave section420, which is generally bowl-shaped.FIG. 22shows a first concavity, following the curve of arrow “A,” andFIG. 22ashows a second concavity following the curve of arrow “B.” Of course, both concavities originate at the outside of reservoir416. Section420is reinforced by metallic doubler428, which may be insert molded to the interior surface of double concave section420.FIG. 24aillustrates an embodiment in which mold426has a groove,427, which forms an integral rib,432, on an outer portion of double concave section420during the process of molding reservoir416.FIG. 24billustrates a similar embodiment in which rib432is formed on an inner surface of section420. In the interest of clarity, mold426is not shown inFIG. 24b, orFIGS. 25aand25b.

In the embodiments ofFIGS. 25aand25b, preformed ribs are insert molded to double concave section420. More specifically, inFIG. 25a, rib436is shown as having been insert molded to an outer portion of section420, and inFIG. 25b, rib436is shown as having been molded or bonded to an inner surface of section420. 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 ribs436, which are placed into the mold426prior to injecting and curing the resin. Ribs436may 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.