Patent Publication Number: US-6340058-B1

Title: Heat triggering fire suppressant device

Description:
FIELD OF THE INVENTION 
     This invention is directed to the field of fire suppressant devices, more particularly to an automatic temperature activated device, a manual device, or a combination thereof, where each version has broad and varied application. 
     BACKGROUND OF THE INVENTION 
     The present invention, in a preferred version, relates to a heat responsive fire suppressant device, of the type that may be mounted in a kitchen range hood, along an automotive engine fire wall, or in industrial locations, where fires could erupt suddenly resulting in serious damage, or even injury. Oftentimes such fires can occur when no one is immediately available to use a conventional, hand operated fire extinguisher, or the fire location is not convenient for using such fire extinguisher. In alternate versions, the device may be operated manually, or the device may offer a combination of automatic and manual. 
     Heat activated fire extinguishers have been proposed which respond automatically to excessive heat to release a pressurized fire retardant agent, where such proposals date back to the 30&#39;s. Hand held fire extinguishers have a number of limitations that are not associated with automatic distinguishers. Most manual extinguishers include either a dry or wet flame retardant chemical compound placed under pressure within a cylindrical canister which includes an opening in a bottom end, a siphon tube connected at one end to the opening and at the opposite end to a valve scaled outlet, an activation device, such as a spring biased hand grip, for opening and closing the valve and a nozzle at the end of a hose which can be used to direct the retardant compound toward a flame to be extinguished. 
     In operation, to extinguish a fire, a user directs the nozzle end of the hose toward the flame and triggers the hand activation device to open the valve. Where the extinguisher includes a hose, the compound is forced therethrough and out of the nozzle end to extinguish the fire. Usually, because the compound must travel through the hose prior to being discharged, hose length is limited so that activation time is reduced, pressure required to force the compound through the hose is minimal and minimal compound is wasted within the hose. 
     A number of limitations are inherent with such traditional fire extinguishers. To be effective, pressure must be maintained at a minimum level. Some extinguishers may be equipped with a pressure scale to visually show the pressure level. Further, while these extinguishers can put out relatively small fires efficiently, assuming the fire is known to the occupant, these extinguishers are typically not suitable for extinguishing larger fires. However, one must be close to the fire, and such close proximity can be a hazard to the user. 
     Certain of these disadvantages can be overcome by the use of automatic, heat responsive extinguishers which are strategically placed in areas for potential fire hazards, such as kitchen hoods in homes and restaurants, engines of automobiles and other vehicles, and in industrial applications. The prior art teaches several devices for the automatic operation of a fire suppressing system, where such prior art is reflected in the following U.S. Patents: 
     a.) U.S. Pat. No. 6,003,609, to Walls, relates to a fire safety device for controlling the spread of fire in a structure. The device comprises a base plate, a smoke detector, a syringe, and a cover. The syringe has a reservoir containing a fire retardant chemical. A fuse link holder has a melting fuse link that maintains a plunger assembly in position, and a spring is loaded behind the plunger. The syringe also has a nozzle in open communication with a supply line, which is in open communication to the reservoir. When a sufficiently high ambient temperature is reached, the fuse link melts, releasing the piston rod from the fuse link and allowing the coil spring to urge the plunger toward the other end of the syringe, and forcing the fire-retardant chemical from the nozzle. 
     b.) U.S. Pat. No. 5,992,531, to Mikulec, teaches a fire extinguisher including a spring biased plunger controlled by a trigger mechanism. The plunger is mounted in a flame retardant compound container and the spring and plunger cooperate, when the trigger mechanism is activated, to discharge flame retardant compound from the container toward a fire. The extinguisher has a handle end and an outlet end at opposite ends of its length such that a user can hold the outlet end in a remote location away from the user when compound is discharged. The extinguisher can also be mounted and provided with a heat sensor for automatic activation. 
     c.) U.S. Pat. No. 4,088,192, to Lamond, is directed to a heat actuated valve comprising a base adapted to be mounted on a fire extinguisher container. The base includes a passage communicable with the container interior. A pair of stop fingers extend forwardly from the base. A fusible element interconnects the stop fingers. The base, stop fingers and fusible element are of one-piece, integral construction. A plunger is slidably mounted in the passage and includes a passage-blocking portion which blocks the passage when the plunger abuts the stop fingers during a fire sensing mode of operation. The plunger is slidable rearwardly to shift the passage-blocking portion to a first passage-opening position to allow the container to be filled. The plunger is operable, in response to melting of the fuse, to spread the stop fingers apart and travel forwardly sufficiently to shift the passage-blocking portion to a second passage-opening position, enabling the container contents to be discharged. 
     While the above prior art, and other known devices, propose solutions to the general subject of automatic, heat activated fire suppressing devices, none offer the simplicity, reliability and fast response of preferred the heat activated fire suppressant device of this invention. Further, these prior art designs significantly limit the location and environment for effective operation. The manner by which the present invention achieves these features will become more apparent to those skilled in the art from the description which follows. 
     SUMMARY OF THE INVENTION 
     This invention preferably relates to a temperature activated fire suppressing device having particular utility in applications where unattended or unexpected fires may erupt. The device, in a preferred embodiment, comprises a cylindrical canister housing, having a uniform bore, and mounting a removable end cap containing a fluid exiting conduit leading to a nozzle mechanism. Alternately, the housing may have different shapes so long as it exhibits a uniform bore throughout. Movable within the cylindrical or different shaped housing is a piston member, cylindrical or comparable shaped to the housing, and axially slidably therewithin, where the piston member is in sealing contact with the inner wall of the housing. The piston member is movable from a first position to a second position by a pressurized fire suppressant fluid in combination with an energy means, where said energy means may be selected from the group consisting of (a) at least one elastic member extending between the end cap and the piston member, and (b) a coil spring positioned behind the piston member. The nozzle mechanism comprises a nozzle opening in communication with the fluid exiting conduit, and a closed cover member. Further, there is a biasing spring acting between said cover member and said nozzle opening to facilitate its removal from the nozzle opening. The closed cover member is temporarily secured to the nozzle opening by a low temperature melting point solder. By this arrangement, when the device is exposed to a fire having a temperature in excess of said low temperature melting point, the solder melts, and with the force of the biasing spring the closed cover member is released from the nozzle opening. With the nozzle opening in communication with the fire suppressant fluid, the fluid is released to act on the fire and is forced out of the device by the release of the stored energy of the energy means. During this releasing action, the piston member is caused to move from said second position to said first position. 
     Accordingly, an object of a preferred embodiment of this invention is to provide a convenient and reliable fire suppressing device that is activated by exposure to heat. 
     Another object of the preferred embodiment lies in the use of a heat activated cover member that includes a compressed coil spring to facilitate its separation from the fluid transmission nozzle. 
     A further object of the invention is a fire suppressing device that can be converted to a manually operated device. 
     Still a further object hereof is the provision of piston member in fluid sealing and sliding relationship to the inner wall of the cylindrical or different shaped canister housing. 
     These and other objects will become more apparent from the specification which follows particularly when read by those skilled in the art. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a sectional view of a first embodiment for the temperature activated fire suppressant device according to this invention. 
     FIGS. 2 and 3 are enlarged sectional views, showing an exploded and an assembled view, respectively, illustrating the nozzle and end cap mechanism for the fire suppressant device hereof, 
     FIG. 4 is a sectional view, similar to FIG. 1, showing a second embodiment for the temperature activated fire suppressant device of this invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     The present invention is directed, in a preferred form, to an automatic, temperature responsive fire suppressing device. However, said device may be constructed to function as a manually activated fire suppressing device, or a combination automatic and manual. Notwithstanding the above, the further description will be directed principally to the preferred version. The inventive device hereof will now be described with regard to the accompanying Figures, where like reference numerals represent like components or features throughout the several views. 
     FIG. 1 illustrates a first embodiment for the fire suppressing device  10  of this invention. The device  10  preferably comprises a cylindrical canister housing  12  having a uniform bore throughout its length. However, other shapes are contemplated so long as the bore is uniform along its length. In any case, the rear end  14 , as shown in FIG. 1, may be integral with the housing body, or in the alternative as a separate component fixed to the housing body. The opposite end  16  includes an end cap member  18  secured to the canister housing  12 , by peripheral fasteners  19 , for example, to define, with the canister housing, an internal cavity  20 . In sliding and fluid sealing engagement with the bore of said canister housing  12  is a piston member  22 . With the reciprocal nature of the piston member, the internal cavity  20  thus consists of two axially changing sub-cavities, a forward fluid receiving sub-cavity  23 , and a rearward sub-cavity  23 ′. In a preferred sealing mode for a cylindrical canister, the peripheral face  24  of the piston member  22  includes a continuous rectangular configured slot  26  to receive a continuous O-ring  28 . With the slot  26  so configured, the O-ring  28  may be compressed into the slot to help provide a fluid sealing relationship between the piston member  22  and the wall  30  of said bore. For canisters of a non cylindrical shape, using a comparably shaped sealing member, a peripheral sealing member about the piston is preferred. Regardless of the canister and piston shape, it is contemplated that other fluid sealing means may be substituted for the O-ring or peripheral sealing member. 
     In the embodiment of FIG. 1, movement of the piston member  22  is effected by compression spring or springs  32  positioned within sub-cavity  23 ′, extending between rear end  14  and rear face  34  of piston member  22 , where the piston member  22  is shown in the charged mode in solid lines, and in dotted lines in the exhausted or fluid depleted mode. The operation of the spring  32 , and the manner by which it effects movement of the piston member  22  will become clearer hereafter. 
     The preferred nozzle mechanism  36 , shown at the right in FIG. 1, is best illustrated in FIGS. 2 and 3. The nozzle mechanism  36 , in fluid communication with sub-cavity  23 , through end cap member  18  via opening  38 , comprises a generally circular housing  40  having a spray opening  42  in communication with said opening  38  via conduit  43 . The circular housing  40 , at its distal end, features a circular body portion  44  of a first diameter, a shoulder  46 , and an axially extending concentric portion  48  with a diameter less than said first diameter. Adapted to override and be temporarily secured to the circular body portion  44  is an end cap  50 . The end cap consists of a cylindrical member  52 , closed at one end  54 , having a central bore  56 . The bore  56  is sized to slidable engage said concentric portion  48 , where said concentric portion may be provided with an O-ring  58  to ensure a fluid sealing relationship between the respective components. Additionally, a compression coil spring  60  is provided to be slidably received in the central bore between the bore end  62  and the concentric portion  48 . Thus, by the stored energy of the compressed coil spring  60 , there is the tendency to separate the end cap  50  from the circular body portion  44 . The separated components represents the operating mode for the fire suppressing device of the invention. 
     FIG. 3 illustrates the inoperative mode for the preferred automatic device  10  hereof. It will be seen that the end cap  50 , with coil spring  60  in place, is positioned on shoulder  46  and soldered about the seam of the circular body portion  44 . It should be noted that in place of the seam soldering, a solder pin (not shown) may be used, where the pin is inserted into the body portion  44  and an aligned recess in the concentric portion  48 . As understood in the art, there are a number of low temperature melting solders, having a known fixed melting point, that can be used to temporarily join the components as noted above. That is, when the device  10  hereof is exposed to a temperature in excess of the melting point of the solder, the solder  61  (a pin or about the seam of end cap  50  and body portion  44 ) melts or softens to allow the end cap  50  to be released from the circular body portion  44  under the influence of the coil spring  60 . With the end cap  50  removed, the pressurized fire suppressant fluid in sub-cavity  23  is free to exit the system through conduit  43  and spray opening  42 . The exit of the fluid is facilitated by the stored energy of compression spring(s)  32  acting against the piston rear face  34 . This produces a pressurized spray of such fluid as it exits the spray opening onto the fire. 
     To recharge the device, after restoration of the end cap  50  and coil spring  60 , and resoldering  61  of the end cap to the circular body portion  44 , or solder pin replacement, new fire suppressing fluid may be injected into the canister housing through one-way valve  62  in end cap member  18 . As the fluid enters into sub-cavity  23 , the pressure thereof acts against the front face  64  of piston member  22  forcing the piston member towards the rear end  14 . Concurrent with this action, the compression spring  32  is further compressed storing energy for later evacuation of the sub-cavity  23 , in the manner discussed above, should another fire be detected. 
     FIG. 4 is an alternate embodiment to the device illustrated in FIG.  1 . For this alternate embodiment, the energy means for assisting the evacuation of the sub-cavity  23  may comprise at least one elastic member  66  extending between the piston front face  64  and the inside face  68  of end cap member  18  by fastening means  70 ,  72 , respectively. In the refilling procedure described above, the elastic member(s)  66  are stretched with the result of an energy buildup. Upon release of the fluid, either by the removal of end cap  50 , as noted above, or by a manual means, the stored energy pulls the piston member  22  towards the end cap member  18  forcing the fluid out through the nozzle mechanism  36 . With each embodiment of FIGS. 1 and 4, the end cap member  18  may be further modified by a manually operable valve so as to allow use of the device  10  to manually put out a fire, where the valve may be connected to a hose having a hand held ON/OFF dispensing nozzle, as known in the art. 
     It is recognized that changes, variations and modifications may be made to the fire suppressing device of this invention, particularly by those skilled in the art, without departing from the spirit and scope hereof. It is contemplated that the device hereof may have the dual purpose of both automatic and manual. Further, It may be desirable to incorporate a switch activation means, such as to activate contacts, to set off an alarm, activate a power breaker or anything electrical, or to turn off lights, by way of example, where the switch means may be activated during movement of the piston from the normally open position to the normally closed position, or even by a pressure drop within the canister. Accordingly, no limitation is intended to be imposed on the invention except as set forth in the following claims.