FI63739B - FOERFARANDE FOER ATT FOERSE SPRAENGMEDEL MED TAENDSATS - Google Patents

Description

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Patent · och registerstyrelsen '' AnaMun utlafd och utUkriton pubi <c «nd 29.04.83 (32) (33) (31) fyydutty ttuoUc« ui —Begird prlorltut (71) IMI Kynoch Limited, Kynoch Works, Witton, Birmingham B6 7BA, England-England (GB) (72) Richard Northan Knights, Gloucester GL3 3TX, Peter Howard Whittall, Penkridge, Staffordshire, Gordon Roy Sutcliffe, Hartlebury, no. Kidderminster, Worcestershire, John Francis Hobbs, Sutton Coldfield, West Midlands, George Byron Carter, Lichfield, Staffordshire, Alan Cross, Rubery, Worcestershire, England-England (GB) (7 * +) Qy Kolster Ab (5I *) Method for equipping explosive devices with ignition charge -Förfarande för att förse sprängmedel med tändsats

The present invention is directed to providing explosives with an ignition charge, i. attaching a certain amount of pre-explosive-containing incendiary material to each unit of explosive device, such as a real-time sleeve, a cartridge, or a detonator.

In current practice, the pre-explosive is tastefully manufactured separately from the firing zone in large batches and then equipped. To incorporate the igniter, the explosive is removed from storage and usually mixed with other materials in a relatively large batch, which is then dispensed into the detonator units (e.g., detonator capsules, cores, or detonator capsules). This procedure requires the storage of the pre-explosive in large batches, its transport to the mixing site, the mixing operation itself, the transport of the mixture for the incorporation of the detonator, and the dispensing of the mixture into the explosive units. Because the manufacture and handling of pre-explosives and mixtures containing them are known to be hazardous, there is a risk of explosion at each stage and special precautions are required.

2 63739 DE 1 496 Olö discloses a safer method of supplying explosives with an igniter, but still requires the storage and handling of pre-explosive in large batches. DE-A-2 316 548 discloses a safer method for supplying non-encapsulated gunpowder cartridges with incendiary material, but the method cannot be applied, for example, to supply incendiary material with cartridge detonators or edge discipline cartridges.

It is an object of the present invention to make the connection of an igniter to explosive device units safer. The present invention thus relates to a method of providing an explosive charge with detonating charge by connecting a separate, moist precursor-containing incendiary mass to an explosive device unit, such as an edge chuck cartridge case, a projectile center impact cap or a firing charge unit, and then drying charge unit.

The method is characterized in that the pre-explosive is prepared in situ in or on a blast / subunit unit by combining in situ a) a substantially dry, relatively insensitive premix with at least two substances that react with each other in the presence of a liquid reactant but do not together in a premix if no liquid reaction medium is present, and optionally one or more materials intended as such to form part of the flammable substance, and h) a liquid reaction medium.

The explosive may consist only of the primary explosive. Usually, however, it consists of a mixture of this explosive and other materials, such as, for example, a sensitizer and / or a fuel and / or an oxidant and / or a friction means. When the igniter is a mixture of a primary explosive and one or more other materials, the premix consists of a mixture of said materials and said other materials. In the process of the present invention, a certain amount of premix is preferably metered into or on the starter unit, and then a certain amount of liquid reaction medium is added.

The term "explosive device unit" as used herein means a container or carrier for an incendiary agent, such as a peripheral cartridge cartridge, detonator or detonator capsule, e.g., a shotgun cartridge. The combination of an explosive device unit and a detonator may potentially result in a final detonation, but 63739 is more likely to be only partially completed: for example: for; b) the explosive device unit and / or the igniter body must be reshaped or their position relative to each other must be changed when, for example, in the edge sleeve, the igniter is forced to the edge of the sleeve with a conventional rotating punch.

The method of the present invention has the advantage that it can be automated, whereby the pre-explosive and the liquid reaction medium are automatically dispensed into the explosive means units. In addition, this automated process is preferably combined with other automated process steps; for example, in the case of edge chuck cartridges, this is accompanied by a step of adding gunpowder and bullets.

The igniter should be sensitive to heat, friction, flame, electric spark, shock, or all of these or some other initiator. The material can be designed to generate heat or a spark, rather than substantial amounts of gas, or an explosion. Heat or spark-generating materials are required to ignite gunpowder, while shock-generating materials are generally required to ignite secondary strong explosives, such as the detonator base charge. Examples of preferred primary explosive compounds that may be included in the igniter include heavy metal lymphinates, e.g., lyi jystyfnaat.ti, and heavy metal azides, e.g., lyi jyazide.

In the process of the present invention, the materials that react with each other to form the primary explosive compound in situ are relatively insensitive (compared to the primary explosive compound they form), thereby reducing storage, mixing, and loading problems. For example, lead oxide, carbonate or hydroxide and styphenic acid can be used to form lead styphnate, and sodium azide and lead nitrate can be used to form lead. However, it may be necessary to use some sensitive starting materials; e.g., an explosive composition may contain multiple non-sensitive materials, and it may be difficult or impossible to form all of the required sensitive 4,63739 ingredients simultaneously in the composition: for example, it is difficult to form lead styphnate and tetrazene (commonly used in materials may be required. Thus, it is within the scope of the invention to use sensitive starting materials, but when these are used, only a small amount is required.

The following are advantageous properties of the reaction between said materials for the purposes of the present invention: a) Ease: The reaction should take place without prolonged stirring (preferably no stirring is required at all) and without the need to use well-defined critical reaction conditions such as temperature and pH. .

b) Speed: The reaction should preferably proceed to completion in a short time. However, this is not essential if the incomplete reaction does not prevent further processing, eg molding, drying, addition of gunpowder or bullet during the projectile manufacturing stage, and provided that the reaction is complete by. the product is put to final use.

(c) Compatibility of the various elements: The materials mentioned, any other materials and the liquid reaction medium must be clearly compatible with the material of which the explosive device unit consists (eg the container in which the reaction takes place). Some acids cannot be used in reactions that take place in metal containers, such as bronze edge disc cartridge cartridges.

d) Starting materials: these should be easy to handle in large batches. They should be insensitive to the final product, although small amounts of sensitizing materials, e.g. tetrazene, may be included in the starting materials.

The exchange reaction usually meets the requirements of a) and b) best. The formation of covalent bonds is usually a relatively slow process. Suitable exchange reactions include double decomposition reactions and acid-base reactions. In addition to the exchange reactions, the formation of a mixed crystal has also been found to be a suitable reaction method. Igniters containing mixed crystals are well known in the explosives industry.

63739

The following examples illustrate the invention.

Example 1

A mixture of the following substances was prepared in said weight ratios: a) 100 parts of styphenic acid, b) 100 parts of lead white c) 50 parts of ground glass and d) 50 parts of barium nitrate.

All materials were in dry powder form and all powder particles passed through a 100 mesh (0.149 mm) screen. Upon administration to the edge impact cartridge cartridges, the mixture was moistened with water and allowed to react in situ in the cartridges. It was found that the obtained core with the ignition charge could be made to explode satisfactorily with a sufficient flame. The amount of ignition combination in each case was of the order of 14-15 mg.

Styphinic acid was of the type supplied by Royal Ordnance Factory1, Bridgwater. Lead white is a basic lead carbonate of the general type used in paint pigments with the chemical formula 2 PbCo.j. Pb (OH) 2 ·

The use of styphnate is not limited to the preparation of lead compounds. Other heavy metal stannates can be prepared in a similar manner and have previously been proposed for use in ignition compositions. In addition, the acidic reaction is not limited to the use of lead white (lead carbonate) or lead oxide (PbO). An alternative option is lead hydroxide. The use of lead oxide is particularly advantageous, since no by-products are formed, since lead oxide and styphenic acid combine precisely to form lead phosphate. However, the use of lead hydroxide must also be accepted on this basis, as the only by-product formed is water, which is in any case present as an ionizing medium. In addition, a reaction between lead acetate and styphenic acid is possible. In this case, the expected by-product would be acetic acid, which would be volatile and could be removed during the reaction. The lead white by-product is CC 2, which is removed. Further information on the preparation of styphnates is provided in U.S. Patent 2,295,104 and DE 2,531,997.

Example 2 Multiple salts, especially nitrate! hypophosphites!

Lead nitrate, lead hypophosphite and sand are mixed as 6,637,339 dry powder and a certain amount of dry powder is placed in an edge impact core. About 10-12% by weight of water together with gum arabic and "Lissa-i pol" is then added to the blended powders to form a double salt. Since the mixture now contains the required percentage of water to be moldable, a drying step is not necessary until the core has been subjected to a rotary punch or other device to press the mixture to the edge of the core. Here we-! In the method, the powders can be premixed before being placed in the core or they can be placed independently in the core and this can then be vibrated to mix the powders therein. The mixing step has been omitted from some tests, and nonetheless! this gave a satisfactory product. i

It should be noted that in the process described above, the double salt is allowed to crystallize virtually freely, i.e. without steps to adjust the crystal size, as described in U.S. Patent 2,160,469. The formation of "stretched crystals" referred to in said patent can be performed, in i situ.

The composition is conveniently prepared at ambient temperature, and this has been found to be satisfactory. However, the method should not be limited such temperatures, it may be desirable to adjust the manufacturing temperature above, for example, ambient temperature. Temperatures up to 45 ° C have already proved satisfactory, even higher temperatures can be used depending on the decomposition temperature of the compounds. j i

The molecular weights of lead nitrate and lead hypophosphite are almost the same: these powders are therefore preferably used in approximately equal parts by weight. However, a small excess of either powder j may be found to be advantageous in practice depending on the conditions. However, the invention should not be limited to substantially equal weight ratios, as up to 100% excess of either component has been found to provide a product with satisfactory sensitivity and ignition power.

Example 3 Azides! 16 mg of a dry powder having the following weight ratios was placed in the edge of a cartridge cartridge core with thorough mixing: 1 ii 7 63739 lead nitrate 53% sodium azide 20% ground glass 27% This powder was soaked in 2.4 mg (15% by weight). with) water, and the resulting composition was screwed with a hammer to the edge of the core of the sleeve and then dried. The composition was found to be somewhat powdery, and probably enough water had been added to ensure a complete reaction.

By way of example, a device useful in the method of the invention is shown in Figure 1, which is a schematic diagram of that device.

Figure 1 shows a series of modules 10, 12 and 14.

The module 10 suitably receives the edge chuck cartridge cartridges from the feeder shown by arrow 16 and feeds them to the module 12 at a certain rate. medium, e.g. water, as indicated by arrow 20.

Other treatment depends on the chemistry of the reaction taking place.

If necessary, mixing devices can be used to mix the ingredients in the core. Devices can be used to remove excess liquid in the core when it is no longer needed for the reaction. In all cases, the cores are finally conveyed to the oven schematically indicated in item 22, where the composition in the cores is dried. The dried cores with the charge cartridge can then be conveyed to a line, preferably automated, for refilling the projectile and placing the bullet, unless the cartridge is an empty cartridge.

Claims (3)

63739 8 A method of providing an explosive charge with detonating means by attaching a separate, moist pre-explosive incendiary mass to an explosive device unit, such as a peripheral barrel, a projectile mid-striker or a known-in-situ cap, and then drying the mass, a) a substantially dry, relatively insensitive premix comprising at least two substances which react with each other in the presence of a liquid reaction medium to form a pre-explosive but which do not react with each other in the premix if no liquid reaction medium is present, and optionally one or more is intended as such to form part of the igniter, and b) a liquid * reaction medium. Process according to Claim 1, characterized in that the precursor is lead styphnate, the reactants are styphenic acid and lead oxide, carbonate or hydroxide and in that the liquid reaction medium is water. Process according to Claim 1, characterized in that the pre-explosive is lead azide, the reactants are sodium or barium azide and lead nitrate or hypofoalite and the liquid reaction medium is water. i i l ί i i i