Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62C—FIRE-FIGHTING
  • A62C3/00—Fire prevention, containment or extinguishing specially adapted for particular objects or places
  • A62C3/02—Fire prevention, containment or extinguishing specially adapted for particular objects or places for area conflagrations, e.g. forest fires, subterranean fires
  • A62C3/0292—Fire prevention, containment or extinguishing specially adapted for particular objects or places for area conflagrations, e.g. forest fires, subterranean fires by spraying extinguishants directly into the fire
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62C—FIRE-FIGHTING
  • A62C31/00—Delivery of fire-extinguishing material
  • A62C31/02—Nozzles specially adapted for fire-extinguishing
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62C—FIRE-FIGHTING
  • A62C5/00—Making of fire-extinguishing materials immediately before use
  • A62C5/006—Extinguishants produced by combustion
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D1/00—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires
  • A62D1/06—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires containing gas-producing, chemically-reactive components

Definitions

• the invention relates to fire extinguishing methods and apparatuses which are based on the use of pyrotechnical mixtures as combustion inhibitors that are introduced into the volume being protected.
• a known method of fire extinguishing is one in which an aerosol combustion inhibitor is introduced into the volume being protected using as the inhibitor a powder that partially decomposes in a thermite mixture and releases a gas phase which pseudoliquifies the fire extinguishing powder, thus increasing the pressure in the fire extinguisher body and thereby supplying powder as it exits into the volume being protected (1).
• the slag formed heats the fire extinguishing powder by heat transfer.
• the pyrotechnical mixture plays the role of producing pressure to eject the combustion inhibitor from the fire extinguisher.
• the purpose of this invention is to increase fire extinguishing efficiency, to produce fire extinguishing agents not requiring periodic inspection of their condition, and to improve reliability and service.
• the fire extinguishing method introducing an aerosol combustion inhibitor using a pyrotechnical mixture uses as the combustion inhibitor the combustion products of the pyrotechnical mixture which are released in the form of an ultra- or a highly-dispersed condensed phase, containing salts of alkali and alkali-earth metals or transition group metals.
• the aerosol mixture is cooled before being introduced into the volume being protected.
• Chemical combustion inhibitors in case of fire are introduced into the volume being protected in the form of an aerosol mixture, including gaseous compounds-combustion inhibitors ⁇ as well as ultra-dispersed condensed particles, which as a result of large surface energy are also effective combustion inhibitors.
• the indicated aerosol mixture may be made in various ways.
• the first way consists of burning pyrotechnical compositions which include elements that form compounds in the combustion process ⁇ combustion inhibitors.
• the second way consists of burning a pyrotechnical composition which includes combustion inhibitors as additional agents, and the third way is to produce combustion products containing ultra-dispersed condensed particles.
• the aerosol mixture is also produced by introducing aqueous solutions of combustion inhibitors into the flow of hot gases, which already contain particles of substances that are inhibitors.
• the apparatus for this invented fire extinguishing method which in itself is also an invention, has a body with a nozzle and is characterized in that the body has a pyrotechnical charge, supplied with a remote ignition agent, and there are means for heatproofing the body and reducing the temperature of the gas-aerosol mixture through the use of a heatproof lining of the body and apparatus nozzle.
• the apparatus is supplied with air-injected packing of the nozzle or with a tank containing water or aqueous solutions of combustion inhibitors, having a connection to the body and nozzle.
• Figure 1 gives a general view of the apparatus
• Figure 2 shows the apparatus with the air-injected coolant packing
• Figure 3 shows the apparatus with a liquid coolant system.
• This invention is based on the fact that with the introduction of organic substances of an aerosol mixture into the combustion zone that contain combustion inhibitors and solid particles, the probability of forming a break in the chain mechanism increases substantially in the combustion zone of active radicals (active centers) due to their recombination according to the scheme CH 3 + CH 3 ⁇ > C 2 H 6 or CH 3 + CH ⁇ > CH 4 and so forth, and also due to their retention on the aerosol surface.
• Each aerosol particle fulfills the role of a condenser of energy, released during the recombination reaction of the active radicals. In the absence of energy dissipation an aerosol particle can provide a specific number of recombinations, depending on the mass of the particle and its heat capacity.
• the inhibiting properties grow with the reduction of aerosol particle sizes, however, the presence in the combustion zone of powerful convective flows places limitations on the possibility of such a reduction.
• the magnitude of the aerosol surface energy is determined by the energy of the crystal lattice and the presence of a defective structure on its surface or close to it.
• the table 1 forming a part of this disclosure presents pyrotechnical compositions which were tested and showed favorable results.
• compositions numbered 1-3 in the table are low-energy compositions that make it possible to simplify the solution to the cooling problem of a gas-aerosol mixture.
• compositions numbered 4-8 in the table are characterized by the use of energy additions such as P and Mg. Al and Fe can also be used, but the ignition of the compositions becomes more complicated.
• the minimum aerosol flow rate is 10 to 100 g/m 3 and greatly depends on the degree of cooling and the intensity of aerosol delivery in the volume being protected, and also depends on the character and degree of openness of the volume being protected and the type of fire. Maximum intensification of the delivery process is desirable; otherwise the processes of particle growth and agglomeration substantially worsen the aerosol inhibiting properties.
• a chamber measuring 2.0 ⁇ 2.0 ⁇ 2.9 m was used in which the following sources of fire were arranged: a) a pan with an 0.2 m 2 area and 10 liters of kerosene and b) a fire of firewood weighing 5 kg and rags (1.5 kg), covered with kerosene (Class A and C fires).
• One pyrotechnical charge whose composition corresponded to the one given under No. 5 in Table 1 with a weight of 900 g, was placed in the chamber.
• the fire sources were ignited with a torch, and the charges were remotely ignited with an electric pulse. Ignition time of the fire sources was 3 min. Operating time of the charge was 85 sec. Extinguishing of the fire sources took place at the 70th second, that is, before completion of the charge operation.
• Example 1 shows that realization of this method is also feasible without the use of special constructive solutions, by using simple combustion of appropriate compositions that contain either elements formed in the process of compound burning ⁇ combustion inhibitors, or earlier prepared inhibitors, but it is more effective to carry out this process with the use of apparatus made according to the invention described.
• FIG. 1 While there is a known fire extinguishing apparatus containing a body with a pyrotechnical charge and an outlet nozzle 1, the known apparatus does not provide effective fire extinguishing because this known fire extinguishing apparatus is not an aerosol generator.
• the proposed apparatus in essentially an aerosol generator.
• Figure 1, 2 and 3 show variants of the apparatus.
• the apparatus contains body 1, nozzle 2, pyrotechnical composition 3 arranged in the body, and remote control ignition devices 4.
• the body has a heat protective lining 5.
• the nozzle in the second case ( Figure 2), has air-ejected packing 7 with holes for air intake 8 and in the third case
• FIG. 3 the tank for the coolant liquid is connected to the body and nozzle through openings 10 and 11. Opening 11 has a sprayer for spraying the liquid. Self-destructing diaphragm 12 is at the nozzle outlet.
• Body 1 acts as a combustion chamber and lining for making the pyrotechnical charge airtight.
• the body makes it possible to guarantee a 10 to 12 year storage period for the charges with practically no preventive maintenance.
• the operating pressure in the combustion chamber is not high, on the order of 1.5 to 2 atm, thereby ensuring high work safety.
• the lining 5 first of all, protects the body from heating up and ensures a maximum temperature of 60 to 160°, and secondly (the same as the lining of nozzle 6) additionally reduces the temperature of the gas-aerosol mixture due to dilution of the gas aerosol mixture with the gaseous heat decomposition products of the lining.
• a temperature not higher than 300° can be maintained, that is, a temperature typically lower than the ignition temperature of organic compounds.
• the presence of CO 2 and H 2 O in the lining decomposition products improves the fire extinguishing properties of the mixture.
• Ignition device 4 represents a well known means for producing a heat pulse on command from the control sensors of a fire prevention defense system, and for this reason the device is not examined in detail here.
• pyrotechnical charge 3 is ignited by a heat pulse developed by ignition device 4, and ensures a mass release of aerosol mixture in the combustion process due to use of the suggested compositions; this mixture is ejected through nozzle 2 into the volume being protected, thus ensuring suppression of the fire source because of intensive inhibition of active radicals in the combustion zone.
• combustion inhibitor inhibitors are the only source of cooling liquid, and formation of the gas-aerosol mixture takes place completely outside the combustion zone of the pyrotechnical charge, which in this case may be made of standard powders (mixed, pyroxylin, ballistite).

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• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Health & Medical Sciences (AREA)
• Public Health (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biodiversity & Conservation Biology (AREA)
• Ecology (AREA)
• Forests & Forestry (AREA)
• Fire-Extinguishing Compositions (AREA)
• Fire-Extinguishing By Fire Departments, And Fire-Extinguishing Equipment And Control Thereof (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=21596696

Family Applications (1)

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Cited By (27)

Families Citing this family (1)

Citations (7)

• 1992
  • 1992-02-11 RU SU5026917 patent/RU2008045C1/ru active
• 1993
  • 1993-02-10 WO PCT/US1993/001234 patent/WO1993015793A1/en active Application Filing
  • 1993-02-10 AU AU36639/93A patent/AU3663993A/en not_active Abandoned

Patent Citations (7)

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