RU2151735C1 - Pyrotechnical composition for oxygen producing - Google Patents

Abstract

FIELD: pyrotechnics. SUBSTANCE: invention relates to pyrotechnical composition containing potassium perchlorate as inorganic oxidizing agent and additional addition of molybdenum as fuel at the following ratio of components, wt. -%: potassium perchlorate, 80-95; molybdenum, 5-20. Composition has the following indices: combustion rate is 16-180 mm/s; specific gas evolving is 189-290 cm³/g; oxygen content is 98.5 vol.%, not less; combustion point is 490- 1260 C. Composition can be used for technical oxygen producing. EFFECT: improved properties of composition. 1 tbl

Description

 The invention relates to the field of pyrotechnics and can be used to quickly obtain a large amount of technical oxygen and to create high-pressure gas in a volume.

 In various fields of industry, where oxygen is used in large quantities as an oxidizing agent in carrying out various fast-flowing combustion processes, there are no strict purity requirements for oxygen.

Difficulties in the development of oxygen quick-working pyrotechnic devices are associated primarily with the fact that they must use pyrotechnic compositions that generate a large amount of oxygen under pressure with a relatively high combustion temperature of up to 1000 ^o C and more. And as is known [1], at such temperatures and increased gas pressure, oxygen interacts energetically with metals and their alloys.

Known [2] pyrotechnic composition for oxygen in life support systems on aircraft and underwater vehicles, in rescue respiratory protective equipment. The composition contains, wt.%: Sodium chlorate 75 - 90; magnesium; 2 to 5; catalyst (oxygen compounds of calcium from a series including CaO ₂ , CaO, Ca (OH) ₂ or a mixture thereof) 5 - 23.

The composition has a specific gas evolution of oxygen of 230 - 265 cm ³ / g at a combustion temperature of 610 - 700 ^o C. the composition does not contain toxic compounds. The disadvantages of the compositions is the low speed of propagation of the reaction zone (less than 1 mm / s). Therefore, such compounds are used in oxygen candles, and the oxygen generated by them can be used in human life support systems.

 Known [3] is a composition for producing oxygen through a self-sustaining catalytic decomposition reaction. The composition contains, wt.%: Sodium chlorate 95 - 96; cobalt oxalate 4-5.

The burning rate of this composition is in the range 0.52-0.55 mm / s, the oxygen yield reaches 294.8 cm ³ / g. The disadvantage of the composition is the low burning rate, less than 1 mm / s.

 Known composition [4] for oxygen in the life support systems of aircraft and underwater vehicles, containing, wt.%: Potassium perchlorate 60 - 90; aluminum powder 5 to 30; barium peroxide 5-10.

The oxygen output during combustion of the composition is in the range from 150 to 250 cm ³ / g with its purity of 99.3 - 99.7 vol.% The main impurities in oxygen: moisture vapor 0.2 - 0.6 vol.%; carbon dioxide less than 0.1 vol.%; nitrogen oxides less than 0.01 vol. %; hydrocarbons less than 0.001 vol.%; chlorine is not detected within the accuracy of the determination method. The burning rate of the composition reaches 2.5 - 15.0 mm / s at a combustion temperature, respectively 1100 -1800 ^o C.

The disadvantages of this composition is the relatively high combustion temperature - more than 1100 ^o C and insufficient burning rate - not more than 15 mm / s

 This composition as the closest in technical essence is selected by us as a prototype.

 The present invention solves the problem of reducing the combustion temperature while increasing the burning rate of the oxygen-generating composition while maintaining at a sufficiently high level of specific characteristics for gas evolution.

The technical result obtained by using the invention is as follows:
- the combustion temperature of the pyrotechnic composition 490 - 1260 ^o C;
- burning rate of 16 - 180 mm / s;
- specific gas evolution of oxygen 189 - 290 cm ³ / g;
- gas purity - not less than 98.5 vol.%
This is achieved by the fact that in the pyrotechnic composition, including an inorganic oxidizing agent - potassium perchlorate and fuel - metal powder, according to the invention, molybdenum powder is used as fuel in the following ratio of components, wt.%.

Potassium Perchlorate - 80 - 95
Molybdenum - 5 - 20
Distinctive features of the prototype allow us to conclude that the technical solution meets the criterion of "novelty."

 Analysis of known pyrotechnic compositions did not reveal compositions containing features that match the distinguishing features of the claimed composition, which allows us to conclude that the technical solution meets the criterion of "inventive step". To confirm the compliance of the claimed technical solution with the criterion of "industrial applicability" samples were made and tested, see table.

The compositions are prepared by mixing in a small mixer components that were previously dried at 90-100 ^° C, and for potassium perchlorate, they are preliminarily crushed and the fraction passed through a sieve with a mesh size of 40 μm is selected.

 The resulting mixture is pressed into copper cups in the form of tablets with a diameter of 20 mm, a height of 10 mm with a relative density of at least 0.7. The formation of the combustion front of the composition in the cup was performed using the ignition composition, pressed in the form of a 2 mm tablet.

 The gas evolved during combustion was cooled on a copper-rubber filter with a porosity of 40-50%, located at the opposite end of the copper cup from the ignition, and collected in a combustion chamber in which the test sample was triggered.

 The initiation of burning of the burning pill was carried out by the nichrome bridge of incandescent igniter device.

 The burning rate of the composition in the sample was determined by the time of its combustion. The end of the combustion process was determined by the maximum gas pressure using a pressure sensor installed in the combustion chamber. The response of the test samples was recorded on a H 071 loop oscilloscope.

 The evolved gas was taken from the combustion chamber and analyzed on a mass spectrometer or gas chromatograph.

Data on the composition of the samples and the results of their tests are presented in the table. From the data given in the table, it follows that the invention allows to obtain a high oxygen yield from 189 to 290 cm ³ / g with a purity of not less than 98.5 vol.% At combustion speeds from 16 to 180 mm / s and combustion temperature, respectively, from 490 up to 1260 ^o C.

The optimal values of the combustion rate of 100 mm / s, the combustion temperature of 770 ^o C, specific gas evolution of 270 cm ³ / g are obtained with a ratio of components, wt.%: KClO ₄ 92; Mo 8. The proposed composition allows to solve the problem of creating a quick-generating oxygen generator.

 List of sources used.

 1. V. I. Bolobov A possible mechanism for the ignition of metals in an oxygen stream. // Physics of combustion and explosion. 1998.V 34.N 1, p. 50-56.

 2. Pyrotechnic composition for oxygen production. Description of the invention to the patent of the Russian Federation. RU 2057707. C 01 B 13/02. Published BI N 10, 1996, p. 182.

 3 Composition for producing oxygen. A.S. 1604729. C 01 B 13/02. Published BI N 41, 1990, p. 11I.

 4. Composition for producing oxygen. Description of the invention to the patent of the Russian Federation N 2061650. C 01 B 13/02. Published BI N 16, 1996, p. 190.

Claims (1)

Pyrotechnic composition for oxygen production, containing potassium perchlorate as an oxidizing agent, and a metal powder as a fuel, characterized in that it contains molybdenum as a fuel in the following ratio, wt.%:
Potassium Perchlorate - 80 - 95
Molybdenum - 5 - 20ts

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