Abstract:
A fire retarding missile and method of use having a unitary construction and containing a propulsion system as well as fire treatment materials. Dispersal of the materials can be initiated both actively and passively, with passive dispersal allowing for a fail safe mode of operation. The fire treatment materials are of the oxygen reduction type, and the method of the invention is to target the hot spot of a fire in order to reduce the spread and intensity thereof. An active guidance system may be of the heat seeking type, or may alternatively be remote controlled video. Stabilizer and guidance fins are controlled in response to signals from the guidance system in order to precisely position the device. The device can be modified for use in fires of specific heat ranges by using nose cones designed to melt in a respective heat range.

Description:
1. CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of application Ser. No. 12/061.634. filed Apr. 02, 2008. 
     
    
     2. BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to fire extinguishing methods and apparatus. More specifically, the invention relates to a fire retardant missile which can be targeted to a specific location to suppress or eliminate combustion. 
       STATEMENT OF THE PRIOR ART 
       [0003]    Firefighting techniques have evolved over the years to take advantage of advances in technology to more efficiently control fires. It is well known that the particular technique or device used to control or extinguish a fire is dictated primarily by two factors, namely, the location and area covered by the fire, and the combustible material involved. For certain chemical fires it is well known that water is not particularly effective for extinguishing the fire, though it may be useful for controlling the spread of the fire to adjacent combustible materials. For forest or other large area fires water is effective generally, but vast amounts are required and delivery to remote areas can be difficult if not dangerous. 
         [0004]    In recent years it has been discovered that devices containing various types of flame retardant and/or extinguishing materials may be delivered to the source of a fire to control the spread of the fire. These devices are entirely passive, in that they react to local temperatures at the delivery site, the reaction invariably involving a rupturable membrane which allows for explosive dispersal of the fire treating material. 
         [0005]    Typical of these devices is that disclosed in U.S. Pat. No. 7,121,354 issued to one Munson, Jr. for a fire treating device and method. The device is an elongated cylinder of the rupturable membrane type as described above, which can be delivered by cannon, by rolling or throwing, or by glider or missile. The Munson device suffers from the drawback in that it can only be passively detonated, and is not sufficiently aerodynamic to ensure accurate placement regardless of the delivery method. 
       3. SUMMARY OF THE INVENTION 
       [0006]    The present invention overcomes the disadvantages of the prior art by providing a fire retarding missile and method of use having a unitary construction and containing a propulsion system as well as fire treatment materials. Dispersal of the materials can be initiated both actively and passively, with passive dispersal allowing for a fail-safe mode of operation. The fire treatment materials are of the oxygen reduction type, and the method of the invention is to target the hottest point of a fire in order to reduce the spread and intensity thereof. An active guidance system may be of the heat seeking type, or may alternatively be remote controlled video. Stabilizer and guidance fins are controlled in response to signals from the guidance system in order to precisely position the device. 
         [0007]    The purpose of the Fire Retardant Missile is to reduce the amount of oxygen fires need to continue unchecked combustion. Most notable is forest fire hot spot, the center of a burning building, or an oil fire. Any of these fire conditions can and usually do initially expand uncontrolled. 
         [0008]    The primary object of the invention is to aid the fire fighters in reducing a fire to a controllable level. The inventive device is designed to be manufactured with minimal cost, to be readily available for use by moderately trained personnel. and to present minimal requirements for integration into present day support equipment. 
         [0009]    Accordingly, it is an object of the invention to provide a fire retardant missile which overcomes the disadvantages of the prior art. 
         [0010]    It is another object of the invention to provide a fire retardant missile that can be both passively and actively detonated. 
         [0011]    It is another object of the invention to provide a fire retardant missile which can be operated in a fail safe mode when deployed for active detonation. 
         [0012]    It is another object of the invention to provide a fire retardant missile which is of unitary construction. 
         [0013]    It is another object of the invention to provide a fire retardant missile which has a self contained propulsion system. 
         [0014]    It is another object of the invention to provide a fire retardant missile which has an electronic guidance system. 
         [0015]    It is another object of the invention to provide a fire retardant missile which has a nose cone or other heat sensing device which is selected to melt at a predetermined temperature dependent upon fire intensity. 
         [0016]    The construction of the device would be largely nonmetallic. The device includes a nose cone, heat sensitive retardant release mechanism, impact trigger, fire retardant material reservoir of spun fiber, fire retardant material, fire retardant release valves, outer shell of reinforced plastic, and other components as will be explained in more detail later. A battery and electronics for operating the device in various modes also form part of the invention. 
         [0017]    The fire retardant material release valves are molded into the fire retardant reservoir of spun fiber and constructed with an electro solenoid, a solenoid plunger stop slot, a solenoid plunger, a solenoid plunger stop trigger, a solenoid plunger stop trigger spring, fire retardant vent slots, a positive or hot wire, thermostatic control switch, and an external positive contact for positive battery power. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0018]      FIG. 1  is a cross section of the fire retardation missile device of the invention. 
           [0019]      FIG. 2  is a cross section of the fire retardation missile enhanced with video camera. 
           [0020]      FIG. 3  is a cross section of the fire retardation missile enhanced with heat seeking guidance system. 
           [0021]      FIG. 4  is a cross section of the fire retardant release valves of the fire retardation missile with the solenoid plunger in the closed position. 
           [0022]      FIG. 5  is a cross section of the fire retardant release valves with the solenoid plunger in the open position. 
           [0023]      FIG. 6  is a cross section of an alternative embodiment of the fire retardant. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Referring now to  FIGS. 1-6  the device of the invention, generally indicated by the numeral  10  is shown. The device  10  generally includes as a unitary construction, a fire treating materials container or reservoir  18 , compressed air or secondary propellant container  26 , a valve arrangement  14 ,  22  having various mechanisms to effect release and dispersion of the fire treating materials in response to a plurality of predetermined conditions as will be described in more detail below, and a solid fuel container  34 , all contained within a streamlined, aerodynamic, generally cylindrical housing  24  which includes a nose cone  12  at its forward end. It is to be understood that the device  10  suitably includes some of these components, all of these components, additional components, or a mixture thereof. Additionally, the components need not be present as a unitary construction and alternatively are suitably provided as a number of separately manufactured components. In a preferred embodiment, most of the major components, including the housing  24 , reservoir  18 , container  26 , and valve arrangements  14 ,  22  are to be fabricated from nonmetallic components to reduce weight and cost. Various types of hardened plastic materials can be used as would be apparent to one of skill in the art. 
         [0025]    The nose cone  12  can be made of any high temperature nonmetallic material such as, Polyethylene Terephthalate, High Density Polyethylene, Vinyl (Polyvinyl Chloride or PVC), Low Density Polyethylene, or any material which can be manufactured to reliably melt or decompose within a selected temperature range. Thus, it is a key aspect of the invention to provide for the device  10  a nose cone  12  which melts at a predetermined temperature depending upon the intensity of the fire to which it is applied. In a first passive mode, the nose cone  12  melts allowing the heat sensing components of the valve mechanisms  14 ,  22  to trigger the release of fire retardant materials  20  contained within container  18 , with valve mechanisms  22  also triggered as will be explained below. In a second passive mode, valve mechanism  14  includes an impact trigger. In an active mode, the device  10  may include a video camera or other electronic sensing devices which allow an operator to detonate the device  10  based upon visually obtained information as will be explained in more detail below. 
         [0026]    The melting point of the nose cone  12  would depend on the status of the fire. Generally, a low level fire may require a melting point of just above 300 but less than 600 degrees Fahrenheit. Areas of low-level fires generally have a flame temperature of approximately  680  degrees Fahrenheit. The cone  12  must melt or disintegrate with sufficient amount of time to allow activation of the heat sensitive valve mechanism  14 ,  22  which releases the fire retardant material  20  contained within container  18 . A high level fire with intensely high temperature or hot spots may require a melting point of 1000 degrees Fahrenheit as high-level fires generally have a flame temperature of approximately 1480 to 1680 degrees Fahrenheit. An intermediate level of fire intensity would require a melting point of between 600 and 1000 degrees. Preferably, it is a key aspect of the invention to have at least three temperature ranges for the nose cone  12 , which is attachable to the front end of the housing  24  via a locking mechanism which may be a bayonet type arrangement or any other type of arrangement as would be apparent to one of skill in the art. Given the fire intensities as discussed above, three nose cone  12  units may be supplied with each missile  10 . The units  12  may have melting points of 300, 700, and 1000 degrees F. and be appropriately labeled, allowing the user to attach the appropriate nose cone  12  based upon the measured or estimated temperature of the fire to be treated. 
         [0027]    The fire retardant materials reservoir  18  is of a generally cylindrical shape and includes an opening  62  formed at the forward end which is sealed by valve mechanism  14 . Additional valve mechanisms  22  are arranged in four regularly spaced rows on the reservoir  18  sidewalls, with each valve  22  having a corresponding opening  64  formed in the reservoir  18  sidewalls so that the valve  22  can allow the contents of the reservoir  18  to disperse therethrough. Housing  24  has corresponding openings  66  formed therein, the outlet end of the valves  22  flush mounted therewith to maintain the aerodynamics of the device  10 . The arrangement of valves  14 ,  22  allows the fire retardant material  20  to be dispersed in a radial or spherical pattern as would be apparent to one of skill in the art. The reservoir  18  contains the fire retardant material  20  which is preferably a halogen material. Such fire retardant material  20  is also suitably one or more of the following nonexclusive list: dry chemical foam, dry chemical powder, sodium bicarbonate, potassium bicarbonate, purple-K, mono ammonium phosphate, halon 1211, etc. It is to be appreciated that any suitable fire fighting material as known in the art is suitably used with the fire extinguishing device  10 . The reservoir  18  is pressurized with nitrogen to enable the material  20  to be expelled and dispersed in a large radius when the valve mechanism  14 ,  22  is activated. 
         [0028]    The fire retardant release valves  14 ,  22 , are molded into the fire retardant reservoir  18  in fluid tight relation with openings  64  and  62  so as to selectively allow the flow of fire retardant material therethrough. Each of the valves comprises an electro solenoid  102 , solenoid plunger stop slot  104 , solenoid plunger  106 , solenoid plunger stop trigger  108 , solenoid plunger stop trigger spring  110 , fire retardant vent slots  112 , positive or hot wire  118 , thermostatic control switch  120 , and external positive contact  122  for positive power from battery  46 . 
         [0029]    The valve mechanisms  14 ,  22  are heat sensing and are constructed in such a manner that when positive power is applied to the external positive contact point  122  and heat is sensed at the thermostatic control switch  120 , the thermostatic control switch  120  will close providing power to activate the electro solenoid  102 . The activation of solenoid  102  moves the solenoid plunger  104  axially to the open position ( FIG. 5 ) whereupon it is locked in the open position by the solenoid plunger stop trigger  108  and held in place by the solenoid plunger stop trigger spring  110 . The retardant material  20  is then forced out of the vent slots  112  and out into the fire zone. The forward battery  44  provides power for the forward electronics to operating the forward heat detection array and through the thermo switch&#39;s  46  providing voltage to the electro solenoids when the thermo switch&#39;s are activated. 
         [0030]    A key aspect of the invention is a two-stage propulsion system which enhances reliability and increases the range of the device  10 . Accordingly, a solid fuel container  34  is employed in combination with compressed air container  26  to provide for the alternate expulsion of hot gasses or compressed air through exhaust nozzle  42  via orifice  43  to provide motive force for the device  10 . The solid fuel container  34  has a compressed air conduit  32  positioned and directed axially therethrough to allow for fluid communication between the compressed air container  26  and the aft exhaust nozzle  42  as will be explained in more detail below. The compressed air container  26  has an open aft end  68  which is selectively sealed by a valve arrangement  30 . The compressed air or nonflammable gas contained within container  26  is released under predetermined conditions by valve  30  which is activated electronically, with power provided by the forward battery  44 , by an accelerometer and heat detection sensor trigger  38  positioned in the engine nozzle  42  area, the trigger configured in a known arrangement as would be familiar to one of skill in the art. Specifically, when the solid fuel  36  stored within container  34  is depleted and heat is no longer sensed at the engine nozzle  42 , compressed air (or other compressed gas) is released from container  26 , into and through conduit  32 , and out through nozzle  42 , by valve  30  in response to control signals from trigger  38 . A combination of any suitable commercially available heat sensor and accelerometer units  38  may be employed, as would be apparent to one of skill in the art, propelling the device  10 . 
         [0031]    Ignition of the solid fuel  36  is initiated by a solid rocket fuel igniter  48 , which supplies power via the circuit formed from the launch switch (not shown but part of a standard re-usable launch platform), battery  46 , and aft and mid launch rings  50 . 
         [0032]    The device  10  has spring-loaded fins  40  for guidance stability and containment in a launch tube. When the nose cone  12  melts, exposing the heat sensitive retardant release valve  14  and impact trigger  16 , and impact is imminent, and if the heat sensitive retardant release valve  14  fails to activate the fire retardant release valves  14 ,  22 , the impact trigger  16  becomes the primary fire retardant release mechanism. Thus, if the nose cone  12  does not melt, the impact trigger  16  functions as a backup retardant release mechanism. 
         [0033]    Launch facilities may be one of several types such as air vehicle launch tubes or a hang and dropdown arrangement, handheld for smaller devices, ground stabilized mortar type launch tubes or other artillery, mobile vehicles, and water craft. In the event that the device  10  is launched from a launch tube (not shown) launch tube rings  50  are attached to the device  10  in a manner well known to those of skill in the art. The aft and mid launch tube ring  50  have circuit wire connected to the battery  46  such that the aft ring  20  is connected to the solid rocket fuel igniter  48 , and the mid launch tube ring is connected to the battery  46 . 
         [0034]    In operation, a suitable launch platform including a launch tube (not shown) is preferably used. An operator will select a nose cone  12  for the device  10  based upon the measured or estimated temperature of the fire to which it is directed as described above. The device  10  is held in place by the launch tube rings  50 , the mid launch tube ring  50  acting as the grounding ring that connects all the metallic equipment together, thereby reducing static voltage potential differences. Closing a launch switch (not shown) closes the power circuit of the solid rocket fuel igniter  48 , thereby igniting the rocket fuel, and initiating flight of the device  10 . Alternatively, when the launch platform is a drop type as it would be from some aircraft, the device  10  will be held in place by clamps on the aircraft clamping the launch tube rings  50 . The ignition closure switch will simultaneously release the device  10 . Device  200  is launched as described below. 
         [0035]    When the device  10  is launched, at the end of the burn time of the solid fuel  36 , the accelerometer or heat detection sensor trigger  38  will sense reduction in speed and/or heat that will trigger the compressed air release valve  30 . The compressed air  28  will then propel the device  10  to its destination. 
         [0036]    The compressed air reservoir  26  and fire retardant container  18  may be sensitive to extensive time in the heat zone. These containers, preferably being made of spun fiber and resin, disintegrate after the depletion of the retardant material  20 . In the event the reservoir  26  and container  18  disintegrate before full depletion through the designed means, the container  18  will expel the retardant material in an explosive manner due to the compressed gas contained therein. The compressed air container  26  disintegration will have little effect on the fire as it is also filled with nitrogen. 
         [0037]    Guidance of the device may be further enabled by the addition of a video camera  52  in the nose cone  12  that will allow the air launch operator to identify the hot spot of the fire from the device  10  through a monitor receiver in e.g. an aircraft. The device  10  will transmit this data from its transmitter/receiver equipment  54  via antenna  60 . The launch operator will be able to provide guidance assistance to the device, using any suitable servo system  56  which is integrated into the housing  24  of the device  10  in the well known manner, and the stabilizer fins  40 . 
         [0038]    Guidance of the device may be further aided by the addition of a heat seeking guidance system  58 , as is well known in the art, the specifics of which are not a part of this invention. The heat seeking guidance system  58  will identify the area of greatest heat and assist guidance of the device  10 , using servo system  56  and the stabilizer fins  40 . 
         [0039]    An artillery device  200  based arrangement is shown in  FIG. 6 . This configuration is similar to the embodiments shown in  FIGS. 1-3 , except that in lieu of rocket fuel, compressed air, and the corresponding nozzle arrangement, the device  200  is designed to be launched from a recoilless rifle such as a 57, 75 or 108 mm recoilless rifle. The device  200  includes a primer  208  positioned centrally of the rear end, the primer providing a spark for a quantity of gunpowder  206  which is positioned and contained within the device  200 . Impact absorbing material  204  such as flame resistant foam is positioned between the gunpowder  206  and canister  202  of the device  200 . The device  200  is launched by aiming the rifle (not shown) and using primer  208  to ignite the gunpowder  206 . 
         [0040]    When the device  10 ,  200  nears the destination point, heat from the fire melt the nose cone  12 , exposing the heat sensitive retardant release  14  and the impact trigger  16  causing the retardant material  20  to be released. In the event of the device  10 ,  200  reaching its destination before the nose cone  12  has melted, the impact trigger  16  impacting a firm surface will cause the release of the retardant material  20 . 
         [0041]    From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. 
         [0042]    It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims: