in the exemplary form of the invention illustrated in fig1 a novel inflatable bag fire extinguishment apparatus is shown generally at 1 in association with a compartment wall 2 confining a fire zone 3 . the apparatus 1 comprises a reservoir ( bottle or flask ) 4 containing a charge of gaseous vaporizable liquid fire extinguishing agent 5 under pressure . the bottle 4 is equipped with discharge means ( an electrically operated release valve or squib actuated rupture diaphragm ) 6 and an agent distribution conduit duct 7 connected to an inflatable bag 8 within a storage / release container 9 . upon discharge actuation the bag is rapidly expanded into the compartment ( fire zone 3 ) or air inlet into the fire zone 3 upon discharge actuation 6 resulting in release of the fire extinguishing agent 5 from the bottle 4 . also shown is the inclusion of an air ejector / aspirator 10 in the agent distribution conduit 7 for premixing extinguishing agent 5 with external air at concentrations suitable for fire extinguishment . the bag 8 is shown in a deployed state in fig2 in a ventilated 11 , 12 compartment 2 designated as a fire zone 3 . the expanded bag 8 blocks the air flow path 11 and releases fire extinguishing agent thru perforations or pores 13 in the bag material 8 into fire zone 3 to extinguish the fire 14 . fig3 provides an enlarged view of a typical bag storage / dispensing container 9 , the stowed collapsed inflatable bag 8 and a fire resistant flapper door or protective cover 15 through which the inflatable bag enters the fire zone 3 . upon detection of a fire in the compartment the system is actuated by control 6 resulting in release of fire extinguishing agent 5 through the distribution conduit 7 into the stowed inflatable bag 8 causing it to emerge thru the flapper door or protective cover 15 and fully inflate into compartment 2 and thereby block incoming ventilating air 11 which is needed to sustain the fire , displacing a portion of the residual air 12 in the compartment and simultaneously dispersing extinguishing agent into the remaining voids within the compartment thru perforations 13 in a portion of the surface of the inflatable bag 8 thereby extinguishing and controlling the fire in the compartment 2 . the system accomplishes fire control by employing several of the basic mechanisms described earlier in the prior art section of this patent , viz . separation of the oxidizer ( air ) from the fuel , chemical inhibition of the flame process and cooling of combustion reactants . more importantly , the overall efficiency and effectiveness of the extinguishment process is greatly enhanced by significantly minimizing the agent dilution effects of the ventilating air 11 , reducing discharged agent mixing limitations , and increasing agent dwell time within the fire zone area 3 . fig4 through 9 contain many of the same components as fig2 for reference and illustrate additional design options . fig4 shows the fire extinguishing agent 5 exiting the bag 8 through a typical orifice 16 ( example a button hole ) in the bag 8 . a bag may contain many orifices 16 on the fire side 14 of the bag 8 . fig5 shows a bag 8 which ruptures in a controlled way and discharges fire extinguishing agent 5 into the fire area 14 . the bag 8 of fig6 is divided by a non - permeable material 18 which contains a pressure release orifice or check valve 19 and includes a non - permeable material 22 on the upstream side and a permeable material 21 on the downstream side . the agent distribution conduit 7 supplies both compartments of the bag 8 . agent 5 flows from the upstream compartment of the bag 8 through check valve 19 into the downstream compartment of the bag 8 and then exits the bag 8 into the fire area 14 . check valve 19 together with check valve 20 maintains a portion of bag 8 inflated to block air flow even after agent depletion . in fig7 the agent distribution conduit 7 supplies the bag 8 . agent 5 flows from the bag 8 through check valve 19 into the fire area 14 . check valve 19 together with check valve 20 maintains the bag 8 inflated to block air flow even after agent depletion . fig8 shows a bag 8 with the upstream side 22 of the bag 8 constructed of a non - permeable material to prevent agent flow upstream . the downstream side 21 of the bag 8 is constructed of a permeable material to allow agent flow 17 into the fire area 14 . the bag 8 of fig9 is constructed of a permeable material 21 with the upstream side of the bag 8 containing a coating of a non - permeable material 23 to prevent agent flow upstream . additionally , a variety of hybrid bag configurations are possible wherein the bag design can include various combinations of the above features , fig4 through 9 , to accomplish fire extinguishment action . lightweight , stowable and strong inflatable bags can be made of a variety of available thermoplastic ( i . e . fluoroplastics and polyimides ) and elastomeric ( i . e . fire resistant neoprene ) materials or fabricated from various high temperature , fire resistant fiber materials such as pbi ( polybenzimidazole ). fabric materials are available aluminized or with other types of laminates or films to provide a wide range of flame radiation and high temperature resistance properties in conjunction with suitable gas permeability and strength characteristics which make them acceptable for the already well defined fire environment exposure conditions associated with typical organic fuel / air fires . for example , the aircraft engine compartment fire scenario thermal radiation exposure levels expected for the deployed bag would be 12 watts per cm 2 for a few seconds . bags can be configured to various shapes and volumes as dictated by the specific nature of the particular fire protection application . available materials also offer a broad range of physical and chemical properties capable of fulfilling both the long term environmental storage and the short term fire exposure requirements dictated by a variety of foreseen fire protection applications . depending on the specific fire protection application , one or more inflatable bags , possibly of different size and configuration , can be employed for effecting air blocking and agent distribution or for just air blockage . while the above description contains many specificities , these should not be construed as limitations on the scope of the invention , but rather as an exemplification of one preferred embodiment thereof . the compartment 2 is only one example of a location in which the system of the invention may be used to great advantage . various alternatives to the pressurized stored gaseous or vaporizing liquid fire extinguishing agent source described in the main illustrated embodiment of our invention are also possible . these alternative sources for gaseous or vaporizable chemical and / or physical inerting agents for example include solid gas generators for the direct production of nitrogen inerting gas and hollow fiber permeable membrane or molecular sieve based generators which produce nitrogen inerting gas by separating it out of the air . accordingly , the scope of the invention should be determined not by the embodiment illustrated , but by the appended claims and their legal equivalents .
a fire extinguishing apparatus for use in normally ventilated or confined spaces of , for example , vehicles , such as an aircraft engine compartment , has an inflatable bag to enhance extinguishing agent performance . the inflatable bag is connected to a source of gaseous or vaporizable liquid fire extinguishing agent which upon discharge flows to the bag resulting in its deployment into the compartment . the bag is configured to block the normal compartment ventilating air path while allowing for dispersal of agent from the bag into the compartment to effect extinguishment .