CS247151B2 - Explosive device filling method - Google Patents

Description

The present invention relates to a method for filling explosive devices in which a batch of wet starting material comprising a primary explosive compound based on styphonic acid and lead is introduced into a well that forms part of the explosive device, followed by drying the wet starting material.

In normal practice, the primary explosive substance is produced away from the fill zone in a large batch, and then stored. During the filling period, the primary explosive substance is separated from the supply and mixed with one or more constituents of the initial charge into a substantially large dose which is then distributed between members of the explosive device, for example, cartridges, cartridges or detonating cartridges.

This sequence involves storing a large amount of the primary explosive substance, transporting it to the mixing station, the mixing process itself, transporting the mixture to the feed zone, and distributing the mixture between the members.

Since the primary explosive compounds and mixtures containing them are, by their very nature, very dangerous in handling, each stage of the sequence is hazardous and requires special precautions.

In the case of some explosive devices, particularly detonators, certain primary explosive compounds themselves may be used as initiators, in which case mixing of the primary explosive compound with one or more other components is unnecessary. However, simply storing a larger amount of a primary explosive compound and distributing it is very hazardous.

The purpose of the invention is to reduce the hazards associated with filling processes.

The method of filling explosive devices according to the invention consists in combining in situ a dry masterbatch containing at least two styphonic acid and lead based components to form a primary explosive compound and, in addition, a sensitizer for the primary explosive compound, an oxidant, a friction agent and / or and a fuel, with a liquid reaction medium.

According to a preferred embodiment of the invention, the masterbatch comprises, as components, a basic lead compound and a styphenic acid, wherein the liquid reaction medium consists of water.

According to another embodiment of the invention, the masterbatch comprises as components styric acid and lead oxide, as oxidant barium nitrate, as sensitizer tetrazone and powdered glass as a friction-inducing substance.

According to a further embodiment of the invention, the masterbatch comprises as constituents styphenic acid and lead oxide, as oxidant barium nitrate and lead oxide, as fuel silicide calcium and antimony sulfide and as a sensitizer tetrazene.

Obviously, the process of the invention eliminates the storage and handling of hazardous primary explosives, such as lead styphnate, and the compounds containing them, in large quantities, which makes the loading process much safer than the conventional loading processes described above.

For example, the member or component of each explosive device may be a mere reservoir, or an igniter carrier, such as a center firing cartridge and a cartridge, for a peripheral ignition for sporting or military ammunition, a detonating cartridge or a retarding device.

Those skilled in the art of explosives will assume many other suitable wells and carriers, so that the invention is not limited to the above examples. The combination of said member and the priming charge may constitute a finished explosive device, but is more likely to be completed only partially; for example

(a) other members may be added to it to form an explosive device, such as a propellant and a rimfire bullet or electric fuse or detonator igniter;

(b) the members may be reshaped or displaced relative to each other, such as when the ignition mixture is being filled into the edge of the peripheral ignition cartridge in the case of a conventional rotating mandrel, or when the ignition charge is pressed against the detonator.

When the starting material is a compound containing a primary explosive and one or more other components, the masterbatch preferably also comprises said one or more other components, wherein the components and impurities are present in the desired proportions to produce the desired explosive after addition of the liquid reaction medium. .

In particular, the ingredients and optionally also the ingredients are to be mixed such that the individual doses may be divided from a plurality of premixes, each dose containing the ingredients and optionally the ingredients in the desired proportions to produce the desired explosive after addition of the reaction medium to the individual doses.

The masterbatch may be distributed between receiving wells, for example, detonator cartridges or edge-firing cartridges or center-fired ammunition cartridges, before adding the reaction medium. Mixing in the receiving well is not essential.

The filling process can be automated. Generally known types of dust dispensing machinery can be used to distribute a larger volume of premix between receiving wells. The distribution of the dry masterbatch may also be accomplished by conventional equipment for distributing the dry explosive.

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Since conventional dry-fill procedures do not involve liquid dosing, it will be necessary to provide a suitable device for dosing predetermined amounts of the reaction medium, preferably water, to the individual receiving wells.

Either the premix or the liquid may first be introduced into the receiving well. The masterbatch may also contain a binder, but otherwise may be included in the liquid dose. The liquid dose may also contain a small amount of a surfactant to promote distraction of the premix reaction medium.

Preferably, the primary explosive is lead styphnate or lead azide. For primers containing lead azide, the masterbatch may contain, for example, lead nitrate and sodium azide. However, other reactants, such as lead hypophosphite or lead acetate, may be used instead of lead nitrate to form explosive lead salts. For example, barium azide may be used in place of lead azide.

When lead styphnate is to be produced, it has been found that the acid-base reactions between styphnic acid and the basic lead compound as individual components have been found to be particularly useful. For simplicity, a masterbatch containing such components will hereinafter be referred to as an acid-base (AB) masterbatch.

Any form of styphonic acid can be used in the premix AB. For example, the acid may be of the purified type (some of its forms are disclosed in U.S. Pat. Nos. 3,983,149 and 4,029,530). Alternatively, the acid may be of a relatively polluted species, such as disclosed in U.S. Pat. Nos. 2,150,653 and 2,246,963. The acid may also be made by more recent techniques, such as those described in British Pat. No. 1,278,576.

The lead compound is preferably selected so as to prevent the formation of contaminants in the filler material or to create readily removable impurities such as water or gas. A particularly suitable compound is lead oxide, whether in the form of a clit or massicot. Another possibility is lead hydroxide and basic or normal lead carbonate.

The acid and lead compound may be present in the masterbatch in stoichiometric proportions.

The masterbatch AB may include additional ingredients necessary to form a complete explosive. The additional ingredients should not interfere with the reaction of the acid and base to an unacceptable degree. However, it has been found that it is possible to form virtually any standard lead styphnate explosive with the aid of the masterbatch AB.

For example, suitable ingredients include:

oxidizing agents: barium nitrate, lead peroxide, lead nitrate, potassium chlorate (unless an ignition agent is required for ammunition where chlorates are undesirable);

friction agents: powdered glass, powdered coal, steel sand;

sensitizers: tetrazene, lead trinitrofluoroglucinate;

fuel sparks: antimony sulfide, calcium silicide, metal powders;

flame retardants evolving gas: nitro compounds such as tetryl and PETN;

binders: acacia, polyvinyl alcohol;

surfactants: lissapol.

As noted above, these additional ingredients may be incorporated into the masterbatch in known proportions to form standard explosives upon virtually complete reaction of the acid and the base to form lead styphnate.

However, the main reaction may be disturbed to some degree. For example, barium nitrate can react to a small degree with styphic acid to form barium styphnate. Since it is not a self-igniting explosive, it does not seem to be associated with problems.

Although the side reaction will indeed reduce the formation of the explosive material, it will be acceptable provided that it does not form a significant proportion of the by-product in the final product.

For ammunition filling, including both sporting and military ammunition of both peripheral and center firing type, the premix AB preferably contains a sufficient amount of styphenic acid and a basic lead compound to form the igniting agent to form lead styphnate in an amount of 20-50 weight percent .

The required proportion of oxidant in the feed mixture depends on the proportions of the other impurities, for example whether or not fuel is treated, as well as the amount of oxygen available from the oxidant: barium nitrate may be present in an amount of 10-60% by weight. . percent, but equivalent amounts (expressed as oxygen yield) of other oxidants may be used.

The glass may be up to 50% by weight. % of the composition, but is usually omitted for central firing ammunition substances and is usually present in an amount of about 20 to 40 wt. % in marginal ignition substances,

Tetrazene may be present in an amount of up to 5 wt. %. In some substances, the fuel, such as antimony sulfide, calcium silicide and aluminum powder, can account for a large proportion of the substance, for example up to 70 wt. %.

The masterbatches can also be used to form two explosives simultaneously. For example, the masterbatch AB may also include the above components to form lead azide.

The invention will now be described by way of example.

Example I

The first embodiment described is an embodiment for filling cartridges with an edge ignition of 0.22 ignition charge, which contains lead styphnate, an oxidant, a friction-inducing substance and a sensitizer. The process comprises forming a dry masterbatch AB of the following materials in the following proportions by weight.

acid styfnová 20-23 % component oxide leaded 19-21 % component nitrate barium 19-21 % oxidant tetrazene 3- 4 % sensibilizer glass 31-39 % friction-inducing substance

Since tetrazene itself is a sensitive explosive, it is first mixed with glass and lead oxide in wet conditions. The resulting tetrazene / glass mixture is dried to form a cake that can be safely shaped into a powder. This powder may be dry mixed with the other materials mentioned above.

247 1 5 1

The masterbatch is prepared in any dosage size, which will depend to some extent. on the size of the ignition charge. An amount of 200-250 grams has proven satisfactory to fill igniting explosive compositions of approximately 20 milligrams per cartridge.

However, in some cases considerably smaller doses, about 20-50 grams, have proven useful. In any case, the masterbatch can be safely handled. The premix is distributed between the cartridges by a conventional filling apparatus, which will be described briefly.

The basic device consists of three filling plates in which an equal number of holes are provided in the same pattern on each plate. One of these plates is placed directly on the other plate and the two plates are movable relative to each other so that their openings can be brought into alignment with each other or out of alignment.

The third plate can accommodate a cartridge for a marginally firing cartridge and can be located below the two second plates, with its openings (containing cartridges) aligned with the openings in the intermediate plate.

A certain amount of premix rakes through the top plate while its openings are out of alignment with the openings of the intermediate plate. As a result, the openings in the top plate fill the premixes and act as volumetric measuring devices.

The top surface of the plate is then bent to Clean, leaving the holes accurately filled. The top plate is then moved to align its holes with the holes of the intermediate plate, and the premix falls through the holes in the intermediate plate into the lower cartridges.

Each cartridge receives a dose of approximately 3 milliliters of water. This can be done in the cartridge before or after the introduction of the premix batch. In any case, water forms a reaction medium that allows the styphnic acid and lead oxide to react in situ to form lead styphnate in each cartridge.

Assuming an approximately complete reaction of styphnic acid and lead oxide, an explosive charge is formed containing about 39-44% lead styphnate. The cartridges containing the wet substance can be immediately transferred to a conventional spinning mandrel which spins the igniting substance into the edge of the cartridge.

The filled cartridges are now transferred to a conventional drying oven in which water is expelled. The total time elapsing between bringing the water and the masterbatch together and transferring the filled cartridges to the drying oven should be sufficient to allow the maximum possible reaction of styphonic acid and lead oxide.

The spinning can be performed at any intermediate time since the reaction can take place partially at the edge of the cartridge. After drying, the cartridges can be converted to load the propellant explosive and insert the bullet according to conventional techniques.

Instead of using conventional masterbatch distribution plates, the masterbatch may be introduced into a dust dispensing machine that automatically feeds the powder of the desired size into individual cartridges.

Where relatively large amounts of water are to be added to the masterbatch, tetrazene from the dry masterbatch may be omitted and may be supplied as a suspension in a batch of water. For example, if 20 ml of water were added to the cartridge instead of 3 ml of water, tetrazene could be included in the batch of water, but the additional water would then have to be removed before the cartridge was spun.

AND

Example

II

The second embodiment relates to the filling of cartridges for center-fired ammunition. The following masterbatch AB is prepared, the proportions by weight of which are as follows:

styphenic acid 19-21% component lead oxide 17-19% component barium nitrate 35-43 i oxidant lead oxide 4,5-5,5 % oxidant calcium silicide 10,5-11, , 5% fuel antimony sulphide 4,5-5,5 % fuel tetrazene 1,5-2,5 % sensitizer

The dry premix is dispensed into the cartridge cases in the same manner as the edge ignition premix in the first embodiment. Each cartridge then receives a dose of water and the acid reacts with the oxide to form approximately 34-40 masses. % lead styphnate per dose. Now there are two possibilities of further processing of cartridges, namely:

(a) the substance may be dried in the cartridge after completion of the reaction, and the cartridge may then be processed as usual, filled cartridges for assembly into battery pockets, which shall then be assembled with the other components of the cartridge;

(b) cartridges containing a still wet substance may be assembled with detonators to form battery pockets and the substance may be dried after such assembly. Moisture leaves the pocket through ignition holes in the detonator chamber.

The latter technique has the further advantage that the substance in the cartridge can be brought into the desired shape while in a wet, relatively plastic state. This facilitates strangulation of the desired dimensions between the anvil point in the battery magazine and the cartridge case.

The shaping of the fabric in each cartridge can be accomplished by the anvil itself. However, these last steps can be used whether or not the explosive is actually formed in situ in the cartridge case.

The invention is not limited to the production of rimfire and midfire ammunition and detonators. For example, U.S. Pat. No. 4,024,818 (Calvin L. Scott and Howard S. Leopold) discloses punctured ignited explosive devices and a variety of explosives therefor.

One such explosive contains both styphnate and lead azide, which can be accomplished by modifying the masterbatch AB to include components (e.g., barium azide and lead nitrate) that allow the production of lead azide.

Other substances listed in the above-mentioned US Pat. No. 4,024,818 (and using 5-nitrotetrazole mercury), but it is possible that these may also be produced in situ.

Still other explosive devices using lead styphnate and / or lead azide are disclosed in U.S. Pat. No. 3,188,914 and British Pat. No. 1,513,056 and these devices are also suitable for filling according to the invention. The invention can also be used to produce igniters for detonators, wherein the explosive is produced in feet on the support wires embedded therein.

However, the invention is not limited to the embodiments described.

Claims (4)

A method of filling explosive devices, wherein a batch of wet starting material comprising a primary explosive compound based on styphonic acid and lead is introduced into a sump forming part of the explosive device, followed by drying the wet starting material, characterized in that The primary explosive compound is combined in situ with a dry masterbatch containing at least two styphonic acid and lead components, and in addition a primary explosive compound sensitizer, oxidant, friction agent and / or fuel, with a liquid reaction medium. 2. A process according to claim 1, wherein the masterbatch comprises, as components, a basic lead compound and a styphonic acid, wherein the liquid reaction medium consists of water. 3. The process according to claim 2, wherein the masterbatch comprises as components stannic acid and lead oxide, barium nitrate oxidant, tetrazene sensitizer and powdered glass as a friction agent. 4. The process according to claim 2, wherein the masterbatch comprises styphenic acid and lead oxide, barium nitrate and lead oxide as the fuel, calcium silicide and antimony sulfide as the fuel and tetrazene sensitizer.