RU2465027C2 - Dry chemical powder to extinguish fire - Google Patents

Abstract

FIELD: fire-fighting means.

SUBSTANCE: invention relates to fire-extinguishing powders based on alkali metals, having the ability to inhibit the process of burning at fire. The proposed means is a dry chemical powder based on mineral salts of alkali metals, which as a base contains cesium sulfate with a specific flow at surface firefighting of classes B1, B2 of 0.3-0.5 kg/m², and at 3D fire fighting - 0.1-0.3 kg/m³, and for classes A1, A2 - 0.2-1.0 kg/m² at surface firefighting, and 0.1-0.8 kg/m³ at 3D fire fighting.

EFFECT: the invention has high extinguishing capability at a much lower flow rate.

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Description

The invention relates to extinguishing powders based on alkali metals having the ability to inhibit the combustion process in a fire.

The prototype of the invention is a general-purpose powder (A.N. Baratov "Combustion - Fire - Explosion - Safety", ed. VNIIPO, p.363, 2003) based on sodium bicarbonate. This powder has the ability to extinguish fires of classes B, C, E, acceptable performance properties (fluidity, no toxicity, etc.) and is relatively inexpensive. However, it is not effective enough, is prone to caking and has other disadvantages.

The aim of the invention is to increase the fire extinguishing ability of powders.

This goal is achieved by the fact that in a fire extinguishing powder based on mineral salts of alkali metals, cesium salts with a specific consumption for surface extinguishing of fires of classes B1, B2 of 0.3-0.5 kg / m ² and volumetric extinguishing are used as the basis of the powder, 0 1-0.3 kg / m ³ , and for classes A1, A2 - 0.2-1.0 kg / m ² for surface extinguishing and 0.1-0.8 kg / m ³ for volumetric fire extinguishing.

The combustion-inhibiting ability of powders based on mineral salts containing alkali metals as cations is due to the presence of low ionization potentials for these cations. Table 1 shows the values of the ionization potentials of substances in various groups of the Periodic Table of Elements of D.I. Mendeleev (see Big Soviet Encyclopedia, vol. 27, p. 265 onwards).

Table 1 I group II group III group IV group V group VI group Perfect. gases ale. ionization. potency. ale. ionization. potency. ale. ionization. potency. ale ionization. potency. ale. ionization. potency. ale. ionization. potency. ale. ionization. potency. Li 5.37 Be 9.30 AT 8.4 FROM 11,2 N 14.47 O 13.56 Ne 21.5 Na 5.09 Mg 7.63 Al 5.94 Si 8.15 R 10.98 S 10.31 Ar 15.69 K 4.32 Ca 6.25 Ga 5.94 Ge 8.10 As 10.05 Se 9.75 Kr 13.91 Rb 4.19 Sr 5.68 Zn 5.76 Sn 7.51 Sh 8.35 Those 8.89 Xe 13.08 Cs 2.86 Ba 5.21 Those 6.06 Pb 7.37 Bi 7.25 - - - -

It can be seen from these data that it is alkali metals that possess the lowest ionization potentials and, correspondingly, the greatest inhibitory ability, and cesium (Cs) of them. The high inhibitory ability of cesium salts is illustrated by the values of the coefficients of heterogeneous recombination of hydrogen atoms (γ _n ) and oxygen (γ _about ) on the surfaces of various salts, shown in Table 2. These data were obtained experimentally by electron paramagnetic resonance (see monograph by A.N. Baratov, A.P. Vogman "Fire extinguishing powder compositions", Moscow: Stroyizdat, 1982, p.66).

table 2 Salt γ _n γ _o NaCl 7.12 12.94 Kcl 8.41 11.58 Na ₂ SO ₄ 4,58 2.2 KHCO ₃ 4.11 3.81 Na ₂ C ₂ O ₄ 3.05 1,69 Li ₂ SO ₄ 3.48 2.24 K ₂ SO ₄ 2.59 7.6 Cs ₂ SO ₄ 12.61 20,0

The table shows that the highest value of the recombination coefficients of atomic particles of hydrogen and oxygen, which are the active centers of chain reactions during combustion, is cesium sulfate (Cs ₂ SO ₄ ).

The present invention proposes to use cesium salts, and in particular cesium sulfate, as the most effective fire extinguishing powders. According to experimental data, the fire extinguishing ability of cesium sulfate in extinguishing fires of classes B1 and B2 is 0.24 kg / m ² , i.e. it is about 5-6 times more effective than PSB-3 powder (1.5 kg / m ² ). More effectively than PF type powders, a powder based on Cs ₂ SO ₄ also extinguishes foci of class A2. The higher cost of cesium salts is offset by significantly lower than conventional powders, the consumption of these salts in extinguishing fires.

Claims (1)

Fire extinguishing powder based on mineral salts of alkali metals, characterized in that cesium sulfate is used as the basis of the powder with a specific consumption for surface extinguishing of fires of classes B1, B2 0.3-0.5 kg / m ² and volume extinguishing - 0.1- 0.3 kg / m ³ , and for classes A1, A2 - 0.2-1.0 kg / m ² for surface extinguishing and 0.1-0.8 kg / m ³ for volumetric fire extinguishing.