RU2213720C1 - Fire-smoking metallized composition - Google Patents

Abstract

FIELD: pyrotechnic materials. SUBSTANCE: invention relates to pyrotechnic compositions and can be used in agents for assessment of fire-fighting equipment and outfit as well as in military equipment for charging various-type blanket ammunition. Composition of invention contains gasoline, metal fuel (aluminum and/or magnesium), and nonmetal fuel: carbon, silicon or red phosphorus, or their mixtures, sodium nitrate or potassium nitrate, butadiene rubber or polyisobutylene, and threadlike polyester. Composition burns with intensive formation of smoke and flame being capable of stably burning on snow-covered surface and easily taking fire from domestic ignition means. EFFECT: enhanced smoking and burning characteristics. 2 tbl

Description

 The present invention relates to the field of pyrotechnic compositions and can be used in certification of fire fighting equipment and uniforms, as well as in defense equipment for equipping various types of fire-fighting ammunition.

 Fires in modern urban and industrial buildings are accompanied by the formation of a large amount of smoke due to the burning of wood and polymeric materials. Smoke extremely complicates the extinguishing of fires, complicates the orientation of personnel and fetters the execution of fire and army units. Particularly difficult is the suppression of long-existing foci of fire and smoke that are resistant to water.

 Therefore, compositions capable of creating long-existing and difficult to extinguish fire and smoke foci during combustion are of considerable interest for developing fire extinguishing means and, as effective incendiary means, these compositions can be used in smoke-burning ammunition.

 It is widely known to use mixtures of metals and nonmetals as pyrophoric systems, for example sulfur, carbon, boron, silicon, phosphorus, with magnesium, aluminum, and titanium. In a number of the listed components, the ease of ignition is combined with a high combustion temperature and calorific value. The combustion of such compositions is characterized by a stable and predictable composition of the combustion products and, as a rule, proceeds very quickly and is not accompanied by smoke formation. Therefore, such mixtures cannot be used as smoke incinerators. At the same time, taking into account high temperatures, completeness of combustion, and ease of ignition, they, as will be shown below, can be of considerable interest as basic compositions for creating metallized mixtures (MS) of smoke-ignition action.

 It is well known to use metallized compositions based on thickened hydrocarbons and metal powders in incendiary munitions. The advantages of such mixtures include manufacturability and the ability to create foci of fire or smoke ", varying in size, ability to spread and hold on an inclined surface.

 The structure of the components included in the MS, incendiary action and a wide range of their combinations are presented in US patent 3464869, CL 149-42, MKI C 06 D 1/10.

 The main structural elements of a metallized mixture, based on this invention, are metallic fuels: aluminum, lithium, magnesium, boron; oxidizing agents: perchlorates and nitrates of lithium, potassium, aluminum, etc .; polymers and liquid organic matter.

 The disadvantages of compositions with the above combination of components include poor flammability, the absence of smoke, the ease of extinguishing a fire using water and sand, which is undesirable for incendiary mixtures.

 The closest technical solution is incendiary substance according to the patent of France, cl. C 06 D 1397964 dated 03/29/1965 "A method for producing incendiary mixtures based on a thickener and liquid hydrocarbon flammable compounds." As the liquid component in the specified metallized mixture, a liquid hydrocarbon compound is used - an aromatic and / or aliphatic hydrocarbon. As thickeners, polyisobutylene and polystyrene are used. In a number of embodiments of the present invention, not more than 30% by weight of powders of silicon or its compounds, or red phosphorus, or aluminum, or magnesium, or mixtures of these metallic fuels are introduced into the thickened liquid fuels. In example 1, in addition to powders of red phosphorus and magnesium, a small amount is introduced - not more than 0.2% of the total weight of all components — sodium nitrate.

 The final composition of the ingredients of the mixture is not controlled and may, judging by the materials of the patent, change as a result of evaporation or evacuation of the composition in the process of pouring it into the ammunition. Thus, the instability of the composition parameters from batch to batch is predetermined in advance.

 The main disadvantages of the composition of the prototype include poor flammability, low levels of flame parameters (temperature and size) and smoke generation, a large mass of a minimal, combustible MC sample, and inability to burn when exposed to a stream of water and on a snowy surface.

 The objective of the invention was the creation of a metallized composition with stable characteristics, burning with intense formation of flame and smoke, able to stably burn on snowy terrain and when exposed to water jets, it is easily ignited by household means of ignition and ignition compounds, traditionally used in incendiary means, and eliminating the need adjustments to the formulation of the composition during use.

 The objective of the invention is achieved in that the composition, including liquid flammable hydrocarbon-containing fuel, metallic and non-metallic fuel, alkali metal nitrate, contains gasoline as a liquid flammable fuel and additionally contains polyester in the form of threads.

The components included in the composition are taken in the following proportions (in% by weight):
Gasoline - 15-40
Metallic fuel - aluminum or magnesium, or their mixture - 5-20
Non-metallic fuel - carbon, silicon or red phosphorus, or a mixture thereof - 10-60
Sodium nitrate or potassium nitrate - 5-30
Butadiene rubber or polyisobutylene - 0.5-6
Polyester in the form of threads - 0.5-2.0
This ratio of components allows for the implementation of the regimes of the chemical conversion of organic fuels and rubbers in the form of pyrolysis with the formation of soot and other types of particles that provide smoke during the combustion of the composition. The main role in ensuring the pyrolysis regimes is played by polyester yarns. Their reaction with an inorganic oxidizing agent begins almost simultaneously with the ignition of the composition and ends very quickly. As a result, a branched pore system is created in the mixture. Filling the pores with gaseous products ensures the flow of pyrolysis throughout the volume of the composition and provides high degrees of conversion of organic fuels to the aerodispersed phase.

The occurrence of pyrolysis reactions in a significant mixture is also caused by high-temperature reactions between metals and non-metals in the mixture. The temperature of such reactions exceeds 2000 ^o C, their heat is above 4000 kJ / kg.

 A significant proportion of the non-metals contained in the mixture ensures the formation of reaction products, for example, silanes, phosphines, etc. as a result of interaction with metals. When water enters substances such as silanes or phosphines, self-igniting substances are formed in the air. Therefore, they are able to maintain the burning of the composition in the snow or when extinguished with water.

 The alkali metal nitrates included in the composition in the amounts indicated in the application materials provide the formation of a high-temperature flame and the combustion of particles of the composition with a mass of less than 1 g. The use of polyester filaments in the composition solves not only the pyrolysis of organic fuels, but also the problem of sedimentation of the components of the composition in the process of equipment and long-term storage. The developed composition is capable of not changing its physical and chemical composition during storage in ammunition for more than 10 years.

 In addition, the use of polyester filaments eliminates the formation of dust particles when fragments of the composition fall on the ground or when they hit a rigid wall that is the surface of the target.

 During the experiments, the minimum mass of the mixture capable of burning was determined, the dimensions of the flame, as well as the dimensions and duration of the smoke screen during the burning of fragments of the composition of different masses. In addition, the ability to burn in the snow particles of the composition of various masses was determined.

 During the explosion of the munition model, the total number of fire sources, the mass of non-combustible particles, and also the size and duration of the existence of the smoke screen were determined. Models of ammunition were made of steel, had a cylindrical shape. The diameter of the layout was 180 mm, its length was 400 mm. The composition of the components of various embodiments of the compositions tested on the experimental basis of the institute is presented in table 1.

 To determine the size and duration of the flame and smoke screen during the burning of individual fragments of the composition of different masses and under the action of the munition model, video and thermal imaging equipment was used. The number of fires in the area during the explosion of the munition was determined visually, as well as as a result of processing video data.

 As follows from the results of the experimental determination of the parameters (table 2), the compositions of this invention significantly surpass the composition of the prototype in the main parameters of combustion and smoke generation: in flame height, critical mass capable of burning, the size of the smoke zone, the number of fires, and the total mass of the ignited mixture and etc.

 The increased duration of combustion of the composition 1 of the prototype due to the inactive mode of combustion of this composition.

 As follows from the data in Tables 1 and 2, outside the optimal range of combinations of the components of the composition (samples 14-16), the main parameters of combustion and smoke formation of the studied samples sharply decrease, which is caused by changes in the temperature regimes of pyrolysis of organic combustibles and worsening conditions of aerosol and gas formation of components in the composition of the invention.

 Based on the results obtained, it can be concluded that the composition according to this invention can be widely used for certification of fire extinguishing agents and for use in various types of ammunition of smoke-burning action, since it burns with intense formation of flame and smoke, is able to burn stably in snowy terrain and when exposed to a stream of water, it is easy to ignite from household means of ignition and igniter compositions, it has stable characteristics.

Claims (1)

Metallized composition of smoke-igniting action, including liquid flammable carbon-containing fuel, metallic and non-metallic fuel, alkali metal nitrate, characterized in that it additionally contains butadiene rubber or polyisobutylene, as well as polyester in the form of threads, while it contains liquid combustible carbon , as a metal fuel - aluminum or magnesium, or a mixture thereof, as a non-metal fuel - carbon, cr mny or red phosphorous or a mixture thereof, and as the alkali metal nitrate - sodium nitrate or potassium nitrate with the following component ratio, wt.%:
Gasoline - 15-40
Aluminum or magnesium, or a mixture thereof - 5-20
Carbon, silicon or red phosphorus, or a mixture thereof - 10-60
Sodium nitrate or potassium nitrate - 5-30
Butadiene rubber or polyisobutylene - 0.5-6
Polyester in the form of threads - 0.5-2.0i

Images