RU2367641C2 - Method to produce porous powder from solid powder chips for sporting and fowling cartridges - Google Patents

Abstract

FIELD: explosives.

SUBSTANCE: method to produce porous powder for sporting and fowling cartridges comprises grinding porous powder into powder chips in aqueous medium, preliminary drying, separation and final drying. Note that, after separation, powder chips are processed on mixing by water solution of acetone with concentration of 75 to 80 % by volume for 120 to 150 minutes with subsequent stripping of solvent. Then powder chips are ground in a drum for 90 to 120 minutes in the mix composed of 0.5 % by weight of graphite and 0.8 to 1.0 % by weight of lithium fluoride of the powder chip weight.

EFFECT: improved looseness, receiving powder elements with porous structure with density of 1.0-1.2 g/cm³ and reduced charge weight to 1,0-1,2 g.

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Description

The invention relates to the production of pyroxylin powders and can be used for the manufacture of gunpowder for small arms cartridges: sport-hunting, pistol, rifle, etc.

A known method of obtaining a porous pyroxylin fine-grained powder (A.G. Goret. Gunpowder and BB, ed. 14, 1972, p.163). To create a porous structure of the powder in this case, a porogen — potassium nitrate in the amount of 45–220 wt.% To the dry mass of pyroxylin, which is then removed by extraction with water to a residual content of not more than 0.5 wt.%, Is introduced into the mass during mixing. The resulting powder in this case has a porous structure, and an apparent density in the range of 1.15-1.52 g / cm ³ and provides ballistic characteristics for many types of sports hunting and pistol cartridges. A negative feature of this method is that water-soluble salts are hygroscopic and agglomerates can form during the manufacture of gunpowder, which leads to the formation of an inhomogeneous pore structure, which worsens the ballistic characteristics of the velocity spread. In addition, the productivity of the equipment decreases, the solvent consumption increases, the ecology of the environment is disturbed due to the discharge of salts with waste water.

There is a method for producing monobasic porous powder by emulsion technology based on SC with a nitrogen content of at least 210.5 ml NO / g and a thermodynamically active solvent of ethyl acetate (Regulation, RTP 14-95, Kazan, 1995, p. 53). The porosity of the powder in this method is created by introducing sodium sulfate and may vary depending on the amount of pore former and the rate of distillation of the solvent. However, unlike the powders obtained by hydropress technology, the spherical shape of the powder elements is not a progressively burning form, this reduces the charge efficiency compared to cylindrical powder when used in the same systems.

A known method of producing pyroxylin porous powder for cartridges for small arms according to patent No. 2165402 dated 04/20/2001 (application No. 99101244) "A method for producing pyroxylin porous powder for cartridges for small arms" by Lyapin N.M., Korobkova E.F. , Staroverova A.A., Gazizova F.F., Grolmana L.V., Alekseeva Yu.V., Lebedeva V.M., Kuznetsova Yu.A. In this method, including the operations of mixing cellulose nitrates, a stabilizer of chemical resistance, the formation of powder elements, removing the solvent by extraction with water, drying, sorting, surface treatment of elements, batch packaging, the porous structure of the powder elements is created by processing elements in aqueous solutions of acetone with a concentration of 30- 70% of the volume for 10-240 minutes with stirring, followed by distillation of acetone from the powder elements after solvent extraction. The disadvantage of this manufacturing method is that the porous structure can only be obtained from gunpowders of small grades such as VU, VT, VTM, P-45.

It is not possible to obtain porous gunpowder for small arms cartridges from gunpowders of large grades (coarse-grained and tubular).

Closest to the proposed technical solution is a method of processing pyroxylin gunpowder into hunting for shot cartridges according to patent No. 2105743 (application No. 93020228 of 02.27.98) "Method for processing pyroxylin gunpowder into hunting powder under shot cartridges" by V. Lebedeva - prototype.

The manufacturing process according to this method is as follows.

Pyroxylin gunpowder with an expired warranty period of storage or taken out of service of any grades (medium-grained, coarse-grained or tubular) is subjected to grinding in an aqueous medium in two stages:

I stage - preliminary grinding;

II stage - final grinding.

In this case, the second grinding stage is the operation of the formation of powder elements. Then it is subjected to preliminary drying, warming, where it is separated from coarseness and dust. After that, suitable fractions with a size of 0.63-0.315 and 0.63-0.80 are subjected to final drying and mixing.

Despite the simplicity of the technological scheme and the exclusion of solvent from production, a negative factor of this method of manufacturing gunpowder is the possibility of using it only for hunting cartridges. It is not possible to use this powder under sports cartridges due to the high density of powder elements 1.58-1.59 g / cm ³ and a large charge of 2.0-2.2 g.

The objective of the present invention is to obtain the porous structure of the powder elements from crumbs to reduce the mass of the charge, improving the flowability of the powder.

To achieve a technical solution for the proposed method, including the operation of grinding powders of any grades in an aqueous medium into crumbs, pre-drying, baking, crumbs, they are treated in an aqueous solution of acetone with a concentration of 75-80% by volume for 120-150 minutes with stirring, followed by distillation of the solvent, gunpowder is polished in the drum for 1.5-2.0 hours with a mixture consisting of 0.5% graphite and 0.8-1.0% lithium fluoride (LiF) by weight of the powder.

The proposed method for the production of porous powder from crushed solid powders for sports and hunting cartridges has been tested under experimental industrial conditions.

Powder 12/7 VA and 14/7 CA were used as raw materials.

Grinding was carried out in a DMK mill in two stages.

Fraction 0315-063 and 063-080 were used as suitable powder elements.

After grinding, the crumb was subjected to preliminary drying, kneading, processing in an aqueous solution of acetone, followed by its distillation and polishing in a drum.

Examples of the method are shown in table 1, physico-chemical and ballistic characteristics of the obtained samples of gunpowder are shown in tables 2, 3.

Table 1 Examples of the method Name of indicator Example No. 1 Example No. 2 Example No. 3 By a known method Grinding scheme: The first stage of the DMK - fr. 0.8-2.2; The second stage of the DMK - fr. 0.7-0.2 Baby FR. 0.7-0.315 - The concentration of acetone in water,% volume 70 75 80 - Processing time, min 120 140 150 The temperature of the mixture during distillation of acetone, ° C 60-91 60-91 60-91 The moisture content of the powder,% 1,0 1.3 1,6 Polishing crumbs in a drum Processing time, h 1.5-2.0 1.5-2.0 1.5-2.0 1,0 The composition of the polishing mixture Graphite 0.1 0.15 0.5 0.15 LiF 1,0 0.9 0.8

table 2 Physico-chemical and ballistic characteristics of the obtained samples for powder powder 12/7 VA Name of parameters Example No. 1 Example No. 2 Example No. 3 By a known method The apparent density of the powder, g / cm ³ 1.3 1,2 1,0 1,58 Fractional composition, mm 0.7-0.315 Ballistic characteristics Cartridge gauge 12 12 12 12 Projectile mass (fractions or bullets), g 32 24 twenty 32 Mass of charge, g 1.95 1.25 1,0 2.0 Average projectile flight speed, m / s 323 340 320 321 The average maximum pressure of the powder gases, kgf / cm ² 644 525 605 624 The rate of expiration of gunpowder (flowability), g / s four four 5 3

Table 3 Physico-chemical and ballistic characteristics of the obtained samples for powder powder 14/7 CA The apparent density of the powder, g / cm ³ 1.4 1.3 1,2 1,59 Fractional composition, mm 0.7-0.315 Ballistic characteristics Cartridge gauge 12 12 12 12 Projectile mass (fractions or bullets), g 32 28 twenty 32.35 Mass of charge, g 1.95 1.40 1.25 2.2 Average projectile flight speed, m / s 321 339 325 319 The average maximum pressure of the powder gases, kgf / cm ² 550 600 620 626 The rate of expiration of gunpowder (flowability), g / s four four 5 3

Table 4 Ballistic Performance Requirements Mass of charge, g Average projectile flight speed, m / s The average maximum pressure of the powder gases, kgf / cm ² Gunpowder type Sunar 20 No more than 1,30 No less than 320 No more than 650 Sports Sunar 24 No more than 1,55 No less than 340 No more than 650 Sports Sunar 28 No more than 1,60 No less than 330 No more than 650 Sports Sunar 32 1.6-1.9 325 450-630 Hunting Sunar 35 1.8-2.1 320 450-630 Hunting

An analysis of the physicochemical and ballistic characteristics of the samples shows that when processing powder crumbs with an aqueous acetone solution with an acetone concentration of about 70 vol.%, The density of the powder decreases from 1.58 g / cm ³ to 1.3 g / cm ³ . However, in this case, gunpowder is suitable for equipping only hunting cartridges.

An increase in the concentration of acetone in the solution from 75% to 80% by volume leads to the formation of a more porous structure, which makes it possible to obtain an apparent density of up to 1.0 g / cm ³ , which provides ballistic characteristics of the powder for a sports cartridge with a fraction of 24 g.

An increase in the concentration of acetone of more than 80% is impractical due to the adhesion of crumbs during processing, which is unacceptable, since it leads to the formation of marriage.

Polishing of activated powder elements after drying in a medium consisting of 0.5% graphite and 0.8-1.0% lithium fluoride to the mass of gunpowder allows increasing gravity and improving the flowability of gunpowder. Improving flowability provides a uniform rate of expiration of gunpowder when assembling cartridges on an automated line, which increases the stability of ballistic characteristics. The proposed manufacturing method allows to obtain gunpowder with an apparent density of 1.0-1.2 g / cm ³ , due to which it is possible to reduce the charge mass to 1.0-1.25 g instead of 2.0 g and obtain ballistic characteristics for sports cartridges.

Claims (1)

A method of manufacturing porous powder for sporting and hunting cartridges, including grinding dense powder into powder crumbs in an aqueous medium, pre-drying, warming, final drying, characterized in that after being crushed, the powder crumb is treated with 75-80 vol.% Aqueous solution of acetone as a solvent for 120-150 min, followed by distillation of the solvent, then the powder crumb is polished in a drum for 90-120 min in a mixture consisting of 0.5 wt.% graphite and 0.8-1.0 wt.% fluoride lithium from m assy of powder crumbs.