RU2272801C1 - Method of preparing fuel mass of mixed solid rocket fuel - Google Patents

Abstract

FIELD: rocket fuels.

SUBSTANCE: method includes preparation of weighed amount of explosive, which is fed by means of feeder into separator to separate foreign inclusions and poured into mixer preliminarily filled with inert medium, after which ammonium perchlorate supplemented by additives is dosed.

EFFECT: enabled safe charging of explosive.

2 cl, 1 dwg, 1 tbl

Description

The invention relates to the manufacture of rocket engine charges from mixed solid rocket fuel (STRT) according to the technology using vertical planetary type mixers (VSPT),

Preparation of fuel mass STRT is an integral part in the process in the manufacture of charges from STRT for rocketry for various purposes.

The preparation of the fuel mass is the initial phase and includes operations such as input control of the components, sifting or filtering them, drying, plasticizing, dissolving, preparing a mixture of liquid-viscous components, preparing a mixture of hardener with additives, dosing and mixing.

Some features in the preparation of the fuel mass are noted in a number of patents on the method of manufacturing a charge from mixed solid rocket fuel: US No. 3562364, 3807272, 4517035; Germany No. 2303065; RF №2167135,2170721, 2194687.

Closest to the claimed invention is a patent of the Russian Federation No. 2226520, C 06 V 21/00, C 06 D 5/06 for a method of manufacturing charges from a mixed solid rocket fuel, which is adopted by the authors as a prototype.

The method provides for the manufacture of the fuel mass by first dosing into the mixer a mixture of liquid-viscous components, a hardener, mixing them, then dosing the powdered components in 2-4 portions when feeding them in a continuous stream while stirring without vacuum and under vacuum after loading the last portion of the powdered components.

In the prototype and analogues according to technological schemes, under the powdered components introduced into the mixer, we mean a mixture of fractions of ammonium perchlorate with powdered auxiliary components.

To increase the energy characteristics of mixed solid rocket fuel (STRT), an explosive, for example, octogen, hexogen, and others, is introduced into it along with an oxidizing agent, mainly with ammonium perchlorate.

Increased sensitivity of explosives to mechanical stresses, to an electric spark is required, to ensure the safety of production, the use of special additional measures for their introduction and preparation of the fuel mass, including remote implementation of the process, control and management.

The disadvantage of the method described in the prototype is the lack of techniques, the order of input and mixing of explosives with components of STRT in a planetary type mixer.

An object of the present invention is to provide a safe method for introducing explosives and preparing a fuel mass.

The technical solution is achieved due to the fact that

1. To a sample of a mixture of liquid-viscous components with additives dosed into a vertical mixer of a planetary type, the explosive is dosed in 1-2 portions, followed by stirring for 5-15 minutes, then a mixture of ammonium perchlorate with additives in separate lines, for which a pre-prepared sample of explosive from the container is fed by a feeder to a separator, where it is separated from foreign impurities, and poured through the valve onto the surface of the mixed fuel mass, while dosing of the explosive begins after complements the free volume of the mixer inert atmosphere (nitrogen or carbon dioxide), which first mixer vacuum pump protected by a filter system creates a vacuum with a residual pressure not exceeding 40 mm Hg. Art., then by supplying an inert gas, increase the pressure in the mixer to atmospheric, displaced from the mixer when loading explosives, the dusty air mixture is sent to the freed volume of the container.

2. The preparation of a mixture of liquid-viscous components with additives is carried out directly in the mixer for the preparation of the fuel mass.

The implementation of the technical solution is carried out according to the attached scheme shown in the drawing.

A predetermined mass of liquid-viscous components with additives, including aluminum powder, is dosed into the mixer. A pre-prepared explosive sample in the container 1 is brought into the fuel mass preparation building, installed above the feeder 2 and connected to it. The free volume of the mixer after loading liquid-viscous components with additives, including aluminum powder, is filled with an inert medium (nitrogen or carbon dioxide) as follows. When the valve 4 is closed, the valves 8 ^a , 8 ⁱⁿ and the open valve 8 ⁶ and the vacuum pump 7 is turned on, through the filter system (vacuum trap 6 ^a , drop catcher 6 ^b , filter 6 ^c ) a negative pressure is created in the mixer 5 with a residual pressure of not more 40 mmHg Art. Then close the shutter 8 ^b , open the shutter 8 ^c and from the cylinders 9 the free volume of the mixer is filled with an inert medium (nitrogen or carbon dioxide) until the pressure rises to atmospheric pressure and close the shutter 8 ^c . Open valve 4 and shutter 8 ^a . The separator 3, the feeder 2 are turned on. In this case, the explosive from the container 1 continuously enters the separator 3, from which the explosive sifted through the perforated sheet through the open valve 4 enters the mixer 5. When the explosive enters the mixer, the dust and gas mixture expelled from it through the pipeline fills the empty volume of the container.

With a small (up to 10%) content of explosive in the composition of the STRT, its weight is loaded in one go. With a higher content of it in the composition, the loading is carried out in two steps: 1/2 portion is served, stirring is continued for 5-15 minutes, then the remaining 1/2 portion is fed with continued mixing for 5-15 minutes.

The need to supply explosives and a mixture of fractions of ammonium perchlorate with powder additives to the mixer in two separate lines is due to the following reasons:

1. It is known that in the presence of substances of organic origin in ammonium perchlorate, explosive characteristics increase. Experimental data also show that, at certain ratios of them (ammonium perchlorate and, for example, HMX), the sensitivity to mechanical stresses becomes higher than that of the starting components.

2. Explosives under mechanical stresses associated with the movement of particles relative to each other, can be strongly electrified with the formation of significant charges of static electricity. Due to the high sensitivity of the explosive to an electric spark, foci of the onset of rapidly spreading combustion, explosion and detonation processes may occur. It has been established that the sensitivity and electrification of explosives to an electric spark in an inert medium (nitrogen or carbon dioxide) is reduced by 5 or more times.

3. In systems with polymeric materials, which include STRT compositions, an increase in fillers leads to an increase in viscosity and yield strength. In highly filled STRT compositions, the filler content reaches up to 85-90%. With a high filler content during mixing, large shear stresses arise in the mass layer and at the interface between the mass and the mixing bodies. Hence, for the safe conduct of the process, it is advisable to introduce explosives, as having a high sensitivity to mechanical stress, in the initial stage, i.e. when the system has a minimum viscosity and a low level of ultimate shear stress.

4. The use of the container version of the explosive packaging allows you to mechanize the loading process, to organize the conduct of the technological process in remote mode. The use of a feeder provides uniform power to the separator and stable operation of the latter. The need for a separator is due to the need to exclude the ingress of foreign impurities, loosening of the product in case of clumping and separation of packed solid lumps, if any. The valve is designed to seal the mixer during the evacuation process.

5. The creation of an inert atmosphere in the mixer can be achieved by pumping air out of it using a vacuum pump, followed by filling with gas (nitrogen or carbon dioxide). When creating a vacuum with a residual pressure of at least 40 mm RT. Art. in the mixer, the oxygen content, on which the sensitivity to the mechanical spark depends, will be a small amount less than 1.2%.

6. When explosive enters the mixer, the dust-gas mixture will be displaced. At the same time, the same volume will be freed in the container. When the mixer is connected to the container, the dust and gas mixture is excluded from the working room.

7. In the manufacture of products of medium and small dimensions in large batches according to the method described in the prototype, to ensure the highest possible productivity, an independent production line is used to prepare a mixture of liquid-viscous components with additives, on which operations are carried out to prepare liquid-viscous and powder components, including aluminum powder, and mixtures thereof. Next, this mixture is metered into the mixer for the preparation of the fuel mass. Then, a hardener and ammonium perchlorate with additives are introduced, mixed without and under vacuum.

When preparing the fuel mass and manufacturing products in small batches with a mass containing in the volume of the mixer or less, the work according to the above scheme by the method described in the prototype becomes economically impractical, because at the same time, irretrievable losses in the form of product residues in the mixer, pipelines and dosing equipment increase, there is a need for frequent cleaning with additional labor costs.

In this case, the most appropriate option would be to dispense liquid-viscous components with additives, including aluminum powder, mix them in the same mixer in which the fuel mass is prepared. After preparing a mixture of liquid-viscous components with additives, including aluminum powder, operations for the preparation of the fuel mass continue in the same manner as after dosing their mixture according to the first scheme.

Comparative features of the manufacturing process according to the invention and the prototype are shown in the table.

Table Comparison of the invention with the prototype. Sequence of operations According to the prototype According to the invention Signs one 2 3 four 1. Preparation of components. is available is available prototype 2. Dosing of components. is available is available prototype 3. Preparation of a mixture of liquid-viscous components and aluminum powder in a separate mixer. is available is available prototype 4. Dosing a mixture of liquid-viscous components and aluminum powder. is available is available prototype 5. Preparation of a mixture of liquid-viscous components and aluminum powder in the same mixer instead of positions 3 and 4. absent is available distinctive 6. Creating an inert atmosphere in the free volume of the mixer. absent is available distinctive 7. The supply of a sample of explosives (consumption from the container, feeding the feeder, separation, pouring through the valve) into the mixer with a parallel flow of displaced dust and gas mixture into the container. absent is available distinctive 8. Stirring after loading each of 1-2 servings of explosive. absent is available distinctive 9. Next, from the load of the hardener and the execution of subsequent operations on the preparation of the fuel mass and the formation of charges. is available is available prototype

The method according to the invention was tested at FSUE Perm Plant named after S. M. Kirov with positive results.

Claims (2)

1. A method of preparing a fuel mass of mixed solid rocket fuel, comprising preparing a mixture of liquid-viscous components with additives, dosing the resulting mixture, hardener, a mixture of powder components in a vertical planetary type mixer and mixing them, characterized in that after dosing in a vertical planetary type mixer a liquid-viscous mixture components with additives in the mixer create a vacuum with a residual pressure of not more than 40 mm RT. Art. a vacuum pump protected by a filter system, then fill the free volume of the mixer with an inert medium: nitrogen or carbon dioxide, increasing the pressure in the mixer to atmospheric, a pre-prepared sample of the explosive from the container is fed by a feeder to the separator, where the explosive is separated from foreign matter and poured through valve 1-2 portions into the mixer on the surface of the stirred fuel mass, followed by stirring for 5-15 minutes, in a separate line, ammonium perchlorate is dosed with the additive E, and displaceable from the mixer in a powder-gas mixture is sent vacated volume of the container. 2. The method according to p. 1, characterized in that the preparation of a mixture of liquid-viscous components with additives is carried out directly in the mixer for preparing the fuel mass.