RU2795967C1 - Method for reducing the detonation critical section of secondary explosives - Google Patents

Abstract

FIELD: processing of explosives.

SUBSTANCE: invention relates to a method for increasing the detonation power of secondary explosives. The method can be used for processing various classes of explosives, for example, nitramines, nitroethers, aromatic nitro compounds in the form of pressed parts or as part of mixed explosives for defense and civil purposes for tasks using explosion energy. The crystals of the secondary explosive are in contact with the coolant without mixing and interaction with each other. The explosive is placed in a heat-resistant container, which is placed in one of two thermally insulated chambers with a coolant. The coolant and explosives are heated in a thermally insulated heat chamber from +50°C to +100°C. The coolant and explosives are cooled in a thermally insulated cold chamber from +10°C to -100°C. The container with explosives is alternately transferred from one chamber to another chamber. One heating and one cooling of the explosive container constitutes a treatment cycle. The total temperature difference in each cycle is 90°C to 200°C. 1 to 30 cycles are repeated, after which the container is removed from the chamber, the explosive crystals are removed from the container and dried.

EFFECT: temperature difference on the explosive, which makes it possible to reduce the number of preparatory operations and the processing time of the explosive.

7 cl

Description

Technical field

The invention relates to methods for processing explosives. More specifically, to a method for increasing the detonation power of secondary explosives (HEs). The method can be used to process various classes of explosives, for example, nitramines, nitroesters, aromatic nitro compounds, etc.

Prior Art

The known method is described in patent No. 2607206 "Method of preparing a plastic explosive composition", IPC: C06B 45/06, C06B 25/00, C06B 21/00; application No. 2014154212, priority 12/29/2014; publ. 01/10/2017, patent holders: Russian Federation, on behalf of which the State Corporation for Atomic Energy "Rosatom" acts - State Corporation "Rosatom" (RU), Federal State Unitary Enterprise "Russian Federal Nuclear Center - All-Russian Research Institute of Experimental Physics" - Federal State Unitary Enterprise RFNC-VNIIEF (RU).

A method for preparing a plastic explosive composition, which consists in mixing a crystalline explosive (BB) with a solution of a plastic polymer in a volatile solvent, followed by distillation of the solvent, granulation and drying, characterized in that before mixing the components, a crystalline explosive from the class of nitroesters or nitroamines is processed by grinding to increasing the defectiveness of explosive crystals and obtaining a rounded shape of particles close to a sphere or ellipsoid, while the average particle size of explosives is 5-10 microns.

Essential features common with the features of the claimed invention: before mixing the components, a crystalline explosive from the class of nitroesters or nitroamines is treated to increase the defectiveness of the explosive crystals.

The disadvantages of this invention include:

- the need to grind the processed particles;

- the described approach is applicable only for classes of explosives nitroesters and nitroamines, which greatly limits the versatility of this method;

- the described method is suitable for the use of processed crystals only in plastic explosives and is not suitable for other methods of manufacturing mixed explosives (for example, casting, emulsions, sol-gel technologies) or parts from individual secondary explosives (for example, pressing, screwing, etc.), which indicates less universality of the proposed method;

- in the patent there is no description of the mechanical part of the processing of the suspension, despite the fact that it is the setting of the processing that is of key importance for obtaining a satisfactory result of the processing.

The known method is described in patent No. 2582705 "Method for producing thin layer explosive charges", IPC: C06B 21/00, F42B 3/10, F42B 3/093; application No. 2015101275/05, priority 01/16/2015; published on April 27, 2016, patent holder: State Corporation "Rosatom" (RU), Federal State Unitary Enterprise "RFNC-VNIIEF" (RU).

A method for producing thin-layer explosive charges, including preliminary preparation of explosives and charge formation, characterized in that powdered explosives from the group of individual nitrogen-containing organic explosives with a vapor pressure of at least 10 ^-5 Pa at temperatures of 80-180 ° C are taken as the starting material, which is then recrystallized by preliminary dissolution in an organic solvent, mainly in acetone, at temperatures in the range of 50-55°C, followed by cooling to room temperature, partial evaporation of the solution and filtration of precipitated explosive crystals and drying them, and then subjected to sublimation (sublimation) in a vacuum at a residual pressure of 10 ^-2 -10 ^-5 Pa from a thermal evaporator having a temperature of 80-180°C, followed by deposition on a substrate that is chemically inert with respect to the vapors of this explosive, using a stencil that limits the contour of the explosive charge.

Essential features common with the features of the claimed invention: the explosive is heated at temperatures of 80-100°C, followed by cooling.

The disadvantages of this invention include:

- the need to use flammable and combustible liquids, which significantly increases the toxicity and danger of the process;

- the need for subsequent disposal or distillation of used flammable and combustible liquids;

- the need for the operation of recrystallization of explosives, which significantly increases the toxicity and danger of the process;

- the need for the operation of evaporation of the explosive solution, which is prohibited by the requirements of explosion safety;

- the need to grind the processed particles;

- high risk of the process due to elevated temperatures up to 180°C.

As a prototype, a technical solution was chosen, described in the RF patent No. 2768622, called "Method for increasing the detonation ability of secondary explosives", application No. 2021119717, priority 07/05/2021, IPC: С06В 21/00. Patent holders: Russian Federation, on behalf of which the State Corporation for Atomic Energy "Rosatom" (State Corporation "Rosatom") (RU), Federal State Unitary Enterprise "Russian Federal Nuclear Center - All-Russian Research Institute of Technical Physics named after Academician E.I. Zababakhin" (RU).

A method for increasing the detonation ability of secondary explosives, including mixing a suspension of explosives in a liquid working medium with subsequent ultrasonic treatment, characterized in that mechanical mixing of a crystalline secondary explosive is carried out in an acoustic liquid that does not mix and does not interact with crystals of secondary explosives at a ratio of explosives : acoustic liquid in the range from 0.5:30 to 2.5:30 parts by weight, centrifugation and repeated mechanical mixing, then ultrasonic treatment is performed in cavitation or pre-cavitation mode, lasting from 5 to 120 minutes, at a suspension temperature of 30 °C to 60°C, followed by filtering the suspension in vacuum to obtain secondary explosive crystals and drying them at a temperature of 60°C-80°C for 4-16 hours.

Essential features common with the features of the invention: secondary crystalline explosives of various classes are subjected to processing, for example, aromatic nitro compounds (1,3,5-triamino-2,4,6-trinitrobenzene (TATB)), nitramines (1,3,5-trinitro -1,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (octogen)), nitroesters (tetranitropentaerythritol (PETN)), etc.; secondary explosive crystals are in contact with the coolant without mixing and interacting with each other, the explosive is heated during processing, the explosive crystals are dried.

The disadvantages of the described invention include:

- lower productivity of the method in comparison with the proposed technical solution;

- the need for preparation and homogenization of the suspension in the centrifugation operation for the processing process.

Disclosure of invention

The task to be solved by the claimed invention is the creation of a method for reducing the detonation critical section of secondary explosives with increased productivity.

The technical result achieved in solving this problem is the effect of a temperature difference on the explosive, which makes it possible to reduce the number of preparatory operations and the processing time of the explosive.

The technical result is achieved by the fact that in the method of reducing the detonation critical section of secondary explosives, which consists in contacting secondary explosive crystals with a coolant without mixing and interacting with each other, heating the coolant, drying explosive crystals, according to the invention, the explosive is placed in a heat-resistant container, which is placed in one from two thermally insulated chambers with a heat carrier. The heat carrier and explosive are heated in the heat chamber from +50°C to +100°C, the heat carrier and explosive are cooled in the cold chamber at a temperature from +10°C to -100°C. The container with explosives is alternately transferred from one chamber to another chamber. One heating and one cooling of the explosive container constitutes a treatment cycle. The total temperature difference in each cycle is organized from 90°C to 200°C. Repeat from 1 to 30 cycles, after which the container is removed from the chamber, the explosive crystals are removed from the container and dried.

The set of essential features allows you to influence the temperature drops on explosives, reduce the number of preparatory operations and the processing time of explosives.

This makes it possible to solve the problem of creating a method for reducing the detonation critical section of secondary explosives with increased productivity.

The analysis of the state of the art carried out by the applicant, including the search for patent and scientific and technical sources of information and the identification of sources containing information about analogues of the claimed invention, made it possible to establish that the applicant did not find an analogue characterized by features identical to all essential features of the claimed invention, and the definition from the list identified analogues of the prototype, as the closest analogue in terms of the set of features, made it possible to identify a set of distinctive features in the claimed object that are significant in relation to the technical result perceived by the applicant and set forth in the claims.

Therefore, the claimed invention meets the requirement of "novelty" under the current legislation.

To verify the compliance of the claimed invention with the condition of inventive step, the applicant conducted an additional search for known solutions in order to identify features that coincide with the features of the claimed invention that are distinctive from the prototype, the results of which show that the claimed invention does not follow for a specialist in an obvious way from the known technical level of technology.

Therefore, the claimed invention meets the requirement of "inventive step".

Embodiments of the invention

The way to reduce the critical section of the detonation of secondary explosives (HE) is as follows.

A sample of the secondary explosive is taken in the mass range from 50 to 1000 grams and the sample is poured into a mesh heat-resistant container for processing with a temperature difference.

Compared with the prototype, where the weight of the sample was allowed to be 25 g, in our invention the weight of the sample allowed for processing without loss of quality is increased to 1000 g. This improves the productivity of the method. In addition, productivity is increased due to the reduction in the number of preparatory operations in the method compared with the prototype. Namely, in the proposed solution, there are no operations for preparing a suspension and selecting crystals from a suspension.

Two thermally insulated chambers are prepared - a heat chamber and a cold chamber.

The temperature in the cold chamber is maintained in the range from +10°C to -100°C. As a coolant, liquids that do not interact with secondary explosive crystals are used, for example, distilled water, liquefied nitrogen, etc. It is allowed to fill the cold chamber with chilled water with ice with a temperature of +10°C to +1°C.

The heat chamber is filled with a coolant - water heated to +100°C. It is allowed to use gas or air heated to +100°C as a heat carrier in the heat chamber. The temperature in the heat chamber is maintained in the range from +50°C to +100°C.

If water is used as a heat carrier during heating and cooling, then it is taken in the ratio of explosives: heat carrier in the range from 1:20 to 1:200 wt.h.

When the ratio is less than 1:20 weight.h., heat transfer is not sufficient for uniform heating or cooling of the sample. At a ratio greater than 1:200 wt.h. there is an overexpenditure of the used energy and heat carriers without a significant improvement in the uniformity of heating or cooling of the sample of explosives.

Cold and heat chambers are thermally isolated from the external environment with a maintained temperature inside, and filled with a coolant that does not interact with secondary explosive crystals.

Alternately immerse the container with a sample of the secondary explosive into the cold chamber, then into the heat chamber. A single movement of the container with a sample of explosives from the cold chamber to the heat chamber is one cycle. The total temperature difference in each cycle should be between 90°C and 200°C.

It has been experimentally proved that the total temperature difference in each cycle less than 90°C is not effective, since it does not lead to a decrease in the critical section of the explosive detonation. The total temperature difference in each cycle of more than 200°C leads to significant cracking of the explosive crystals and their grinding, which is unacceptable.

That is, if the temperature in the heat chamber is +50°C, then in the cold chamber the temperature should be from -100°C to -40°C. And if the temperature in the cold chamber is +10°C, then in the heat chamber the temperature should not be lower than +100°C.

Empirically, it was found that it is allowed to start the process of processing a container with explosives from a heat chamber, or from a cold chamber, since this does not affect the technical result.

The duration of exposure of the container with a sample of explosives in the heat or cold chamber is selected in the range from 1 to 20 minutes, depending on the weight of the sample.

An exposure of less than 1 minute does not allow achieving the required uniformity of cooling or heating of the treated substance, which is a negative factor for reducing the detonation critical cross section. Exposure for more than 20 minutes leads to a greater consumption of the coolant without a significant improvement in the uniformity of the cooling of the processed substance.

Compared with the prototype, in which a single sample of explosives cannot exceed 25 g, the processing time is up to 120 minutes, in the proposed technical solution, it takes 60 minutes (30 cycles of 2 minutes) to process 25 g of a sample of explosives. Thus, reducing the processing time of explosives increases the productivity of the method.

At the end of all cycles, the container is removed from the chamber, the secondary explosive crystals are removed from the container and dried. To determine the critical detonation section, rods with different cross sections are made using secondary explosive crystals. The critical section of detonation is considered to be such a section of the explosive charge at which the propagation of self-sustaining detonation becomes impossible.

The value of the detonation critical section is estimated for explosive rods of equal density. The critical detonation cross section of an explosive rod made using secondary explosive crystals from the nitramine class prior to treatment by exposure to a temperature difference was 2.05 mm ² . The critical detonation cross section for a rod made using a secondary explosive from the class of nitramines after five cycles of treatment with a temperature difference was 1.54 mm ² . As can be seen from the results, the use of temperature-treated secondary explosive crystals from the nitramine class makes it possible to reduce the detonation critical cross section by ≈25%.

Depending on the setting and the number of cycles, the proposed method allows to reduce the detonation critical cross section of secondary explosives by 10 to 35%.

The processing of the sample of the secondary explosive may contain from 1 to 30 cycles. It was experimentally proved that treatment with a duration of 1 cycle leads to an insignificant change in the detonation critical section, and treatment with a duration of more than 30 cycles leads to an increase in the process time without significant changes in the detonation critical section.

The achieved technical result is ensured not only by the presence of known distinctive features, but also depends on their interaction with other essential features of the proposed method, which allows it to expand its functionality and provide a high technical result compared to the prototype.

Industrial Applicability

It is possible to use the invention both independently - in the form of pressed parts, and as part of mixed explosives for defense and civil purposes for tasks using explosion energy.

The method was implemented from currently known materials and on existing equipment. The proposed method was tested. The results obtained confirmed the claimed technical result and prove the operability and industrial applicability of the method for reducing the detonation critical section of secondary explosives.

Claims (7)

1. A method for reducing the detonation critical section of secondary explosives, which consists in contacting secondary explosive crystals with a coolant without mixing and interacting with each other, heating the coolant, drying the explosive crystals, characterized in that the explosive is placed in a heat-resistant container, which is placed in one of two thermally insulated chambers with a coolant, heat the coolant and explosive from +50°C to +100°C in a thermally insulated cold chamber, cool the coolant and explosive from +10°C to -100°C in a thermally insulated cold chamber, alternately transfer the container with explosive from one chamber to another chamber, while one heating and one cooling of the container with explosives constitute a processing cycle, the total temperature difference in each cycle is organized from 90°C to 200°C, repeated from 1 to 30 cycles, after which the container is removed from the chamber, removed from container of explosive crystals and dry them. 2. The method according to p. 1, characterized in that water is used as a heat carrier during heating and cooling in the ratio BB : heat carrier in the range from 1:20 to 1:200 wt.h. 3. The method according to p. 2, characterized in that water with ice with a temperature of +10°C to +1°C is used as a coolant during cooling. 4. The method according to p. 1, characterized in that heated gas is used as a heat carrier during heating. 5. The method according to p. 1, characterized in that liquid nitrogen is used as a coolant during cooling. 6. The method according to p. 1, characterized in that the treatment cycle begins with the cooling of the coolant and explosives. 7. The method according to p. 1, characterized in that the treatment cycle begins with heating the coolant and explosives.