KR830001033B1 - Method for manufacture of low - energy detonating cord - Google Patents

Abstract

The continuous solid core of a high explosive compound in formed by projection, and moved into the movable cage of a fibrous tissue formed under enough stretching force. The cage is coated with a layer of soft plastic material, and the plstic material is hardened.

Description

Manufacturing method of low energy dopant

1 and 5 are partial cross-sectional perspective views showing different embodiments of the dopant produced by the present invention.

2 is a schematic diagram of a device used in the present invention.

3 and 4 are cross-sectional views showing different embodiments in part of the apparatus of FIG.

FIELD OF THE INVENTION The present invention relates to a process for the manufacture of improved bombardments used to deliver explosive waves to explosive charges, and more particularly to a process for fabricating known as "Low-Energy Detonating Cords."

Accidents that may occur when an electrical detonator is used to explode explosive charges in mines, such as lightning, static electricity, battery action, drift current, drift electricity or foreign electricity from power sources such as radio transmitters or transmission lines Detonated accidents are well known.

For this reason, non-electrically detonating with suitable explosive fuses or detonators has been widely considered an alternative. A typical high energy detonation line has a uniform explosion rate of about 6000 m / sec and a combination of materials such as fiber, waterproof material, plastic, etc., with a cord made of pentaerythritol tetranitrate (PETN) of 6-10 g / m. It was coated with. However, the noise generated when the core explodes such a PETN sediment on the surface is so large that it is often unusable for explosive work in developed areas. In addition, the destructive force of such a dopant is sufficiently large, and it may be transmitted to the dopant which the explosion wave is adjacent, or the explosive lump which the dopant line contacts. In the latter case, such a detonation line cannot be used when attempting to detonate the explosive charge at the bottom of the drilling hole.

In order to overcome the problems related to noise and high breakage force in the above-described 6-10 g / m width line, a low energy line width line (LEDC) has been developed. The LEDC has an explosive charge of about 0.02-2 g / m in the core, and usually about 0.4g / m. The characteristic of such a detonation line is that it has a low breaking force and low noise, and thus can be used as a trunk line when the noise should be enjoyed to the minimum, or as a lower line when detonating an explosive filling at the bottom of a drilling hole.

The low-energy dopant described in U.S. Patent No. 2,992,210 is covered with a metal sheath of a core-like granular, high-performance explosive of about 0.02-0.4 g / m, such as PETN, which can be covered with a fabric or plastic on it. . When the explosive charge amount in the core is such low, it is described that metal coating is essential for explosion propagation.

Metal-clad LEDCs are not suitable for continuous manufacture of infinite lengths, and because conduction of electricity along the entire length of the LEDC is due to the conductivity of the metal coating, attempts to overcome the problem by removing metal coatings with other measures have been made. There were several times. These attempts have not been fully successful, especially if the core load is less than 0.4 g / m. For example, according to US Pat. No. 3,125,024, when the specific surface area of PETN is about 900-3400 cm 2 / g, the granular core is placed in a fabric coating and then protected and reinforced (including a thermoplastic layer or a second fabric coating). When a series of waterproof and reinforcing materials) is applied, it is known that a uniform explosion rate can be obtained even when 0.32-2 g / m of granular PETN is loaded in the core without a metal coating. However, fabric sheathing is expensive to use, due to the type of equipment required and by one of the dopant production rates thereby. Moreover, even if the specific surface area of PETN is high and wrapped in woven and thermoplastic coatings, it is impossible to achieve a reliable high-speed explosion when it is at the lower limit of the LEDC range of the deep loading of PETN.

Another energy depletion line according to British Patent No. 815,534 and U.S. Patent No. 3,311,056 has its explosive core covered with a polymer. The granular core of the dopant according to the British patent is encased in a flexible coating made of thermoplastic polymer with a fine explosive of 0.4-3 g / m, which is wound around a fabric or wire to increase strength and abrasion resistance. Can be. The explosive line according to the U.S. patent is not broken because an expandable thick coating made of elastic polyurethane surrounds the explosive core, and in order to prevent breakage, the explosive charge indicated in units of g / m is used. The ratio between the amount and the thickness of the coating in units of cm is less than 11/1, preferably 0.8 / 1-8 / 1, and the explosive charge of the core is 0.2-80 g / m, preferably 0.4-20 g / m. to be. Therefore, such a dopant is of a type including both a high energy and a low energy dopant. In addition, the 0.4-4 g / m dopant according to the patent has a PETN core in a lead coating. In addition, explosive cores with self-supporting compositions in the form used for plate explosives are also known, as described in US Pat. Nos. 2,992,087 and 2,999,743, although low energy dopants having a loading of 1-2 g / m are granular explosive cores. It is contained in lead coating and has a low ratio of explosive charge capacity to polyurethane coating thickness (4-1.7 g / m. Per cm of coating thickness).

According to U.S. Patent No. 3,384,688, a method for producing a special fabric coating cord is known in which a fine granular PETN core is used at a loading amount of 2 g / m, which increases the sensitivity to lateral detonation and increases the explosion propagation ability even at a low loading density. have. According to U.S. Patent No. 3,382,802, the core is made of metal or thermoplastic material with a granular primary explosive having a maximum particle size of 100 microns and at least half of the particles less than 50 microns with a low loading of 1-2 g / m. A case is described in which a material is placed in a spirally wound sheath and covered with a spirally wound fiber sheath and a thermoplastic shell.

As can be seen from the above, conventionally, only granular explosive cores have been used for the dopant ship in which the core portion has a loading of 2 g / m0 or less. Moreover, it is common to use metal or strong fabric sheaths, especially when the loading amount is below 0.4 g / m. The self-supporting explosive composition which mixes a crystalline high performance explosive compound with a binder can be rapidly injected in the form of a dopant, and a higher production rate can be obtained than a dopant which has a granular core. In addition, the combined explosive composition is high in density and can explode at a higher rate than a low density explosive for a given diameter. However, since the combined explosive composition contains less sensitive materials, such compositions are less susceptible to detonation than compositions of granular explosives in total, and therefore are not expected to explode under the same conditions as such granular compositions. Although the dopant with bound explosive cores is known from US Pat. No. 3,311,056, the cores in this case are granular PETN and leadazide / aluminum, which are also contained in lead coating. It is also known that in order to propagate the explosion of the self-supporting explosive composition at a uniform and high speed, the diameter of the dopant wire and the charge amount of the explosive charge must be sufficiently large. According to the aforementioned U.S. Patent No. 2,992,087, it is also known that a dopant made by injecting a PETN plate explosive based on nitrocell luroose with a PETN loading of 4 g / m explodes at a speed greater than 6400 m / sec. In addition, the aforementioned U.S. Patent No. 3,311,056 describes a combined explosive core portion having a PETN loading of 3.7-4 g / m. However, it is true that the explosives, where the explosive is loaded with a combined explosive core with a loading of 2 g / m or less, have been avoided, although it is known that granular PETN explosives of the same loading can be worked. U.S. Patent Nos. 3,338,764, 3,401,215, 3,407,731 and 3,428,502 are also known to produce explosive charges having an explosive charge of 10-40 g / m by injecting explosive compositions bonded with elastic materials, in this case axially It is preferable to inject around the reinforcing seal located. It is known to coat reinforcement seals on extruded dopants or to bond the seals with raw rubber or liquid polymers to the dopants than to place the reinforcement inside.

In the case of manufacturing the dopant line, a thread has been used to make it easier to coat the powder explosive core. For example, U. S. Patent No. 3,683, 742 rounds one or several coarse threads into the funnel and supplies powdered explosives to the continuously produced coating at the bottom of the funnel. At this time, the yarn is bent from the vertical axis of the funnel and enters the coating together with the explosives. The thread enters the coating with the explosive in powder form, and as a result, a granular explosive core is formed around the inner thread.

According to British Patent No. 1,416,128 and Belgian Patent No. 815,257, a column of dry powder explosives is held in an axial stall coupled to each other, and the column / thread combination is pulled out through a compression die while applying tension to the yarn. It is also known to form the core of the explosion fuse. The core thus formed is wrapped around the explosive and forms a sleeve around it, which is then wrapped with a fabric reinforcement layer and then covered with plastic to be waterproof.

According to US Pat. No. 2,687,553, it is also known to use longitudinal yarns for the production of dopants for the purpose of reinforcing thermoplastic coatings and overcoming their elasticity. The core of the dopant thus produced is trapped in a sheath of thermoplastic material with a strong seal in the longitudinal direction. The entire periphery of the explosive core is in direct contact with the thermoplastic coating and the yarn is surrounded by a thermoplastic material.

The method for manufacturing the dopant wire according to the present invention is

(a) forming a mixture of crystalline high performance explosive compounds and binders sensitive to primers into continuous solid cores, such as by injection;

(b) stretching the fiber strands under sufficient tensile force to form a moving cage of longitudinally parallel fiber strands;

(c) making the moving cage a carrier of the core by allowing the core to be moved inside the moving cage;

(d) usually, after the core has been moved into the moving cage, a layer of soft plastic material is applied around the moving cage without changing the diameter of the core;

(e) consists of curing this plastic material.

In one preferred embodiment of the method, the core is injected into a continuously moving fiber cage and the core in the cage is passed through a plastic-coated injection die with or without support around it, in which case the integral cage And a sheath of three plastics. In another embodiment, the fiber strands, the movement and the formation of the coating are all done in a die, where these three operations may be performed simultaneously or may be made after the core is moved. In each case, there is little reduction in core diameter due to compression.

In addition, the apparatus for carrying out the method for producing a dopant wire of the present invention:

(a) a first injection autonomous unit for forming a mass of deformable bond explosive composition into a continuous solid core;

(b) means for arranging the fiber strands parallel to one another in an annular fashion;

(c) means for stretching the parallel fiber strands under sufficient tension to form these islet strands into a moving cage, wherein the fiber strand arrangement means and the first injection device have cores emerging from the first injection device in the cage; Is maintained in a positional relationship so that it can be moved integrally and transported by this cage);

(d) a second injection device for forming a sheath of soft plastic, wherein the second injection device and the first injection device and the fiber strand arranging means have a cage including a core portion coated with a second injection device; At the same time, at the same time or afterwards, the positional relationship is maintained so that the reduction of the core diameter does not occur);

(e) means for receiving a passage of a coated case comprising a core to allow the plastic material as the coating to cure; It consists of.

The injection chamber of the first injection device preferably includes an opening for forming a vacuum and particle filtering means for removing particulate matter having a large particle size from the core portion. The fiber strand arranging means may have the form of a guide plate independent from other parts, or may be an accessory of the second unloading device.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Referring to the low energy depletion line 1 of FIG. 5, the continuous solid core 2, shown in cross section, consists of a deformable bond explosive composition such as fine PETN mixed with a binder such as plasticized nitrocellulose. The diameter of the core is determined to contain about 0.1-2 g / m explosive in the longitudinal direction of the core. The protective coating 4 made of plastic has a thickness of, for example, about 0.127-1.905 mm, and surrounds the core 2.

In the width-of-width line 1 shown in FIG. 1, the core 4 is arranged parallel to the longitudinal axis of the core 2 around the core 2 of the core reinforcement 3 made of a plurality of fibers, and the coating 4 is provided with a core ( 2) and the core reinforcement (3).

In part of FIG. 5 the sheath 4 is removed to show the periphery of the core 2, and in part of FIG. 1 the sheath 4 is removed to surround the fiber strand 3 on the core 2. At the same time showing the shape, the fiber strands 3 are removed to show the shape of the periphery of the core 2.

The low energy dopant prepared in accordance with the method of the present invention is characterized in that the core of a continuous solid (i.e. non-solid solid) has a low charge amount (e.g. 0.1-2 g / m) of crystalline high performance explosives and a deformable binding explosive with a binder thereof. Composition, and only a thin protective plastic coating surrounds the core. A further preferred form of branching is that the outside of the core is reinforced with longitudinal fiber strands. Contrary to conventional knowledge of low energy dopants, deformable bond explosives in the form of a dopant can be coated with metal or fabric, spirally woven fabrics, plastics, metal wires or metal filaments, when the loading is less than 1-2 g / m. Or it was found that even without being wrapped in a thick plastic sleeve, the explosion could be propagated uniformly at a speed useful for explosion operations (eg, about 4000 m / sec or more). If the core is a continuous solid rod of at least about 55% by weight of explosives (such as plastic bond explosives) containing at least about 55% by weight of explosives and fine crystalline high-performance explosives, and the reinforcement is on the outside of the core, wrapping it with a coat or the like as described above I found it unnecessary.

In the dopant produced according to the method of the present invention, the explosive particles in the core are combined with a binder (e.g., an organic polymer composition), thereby making the core density uniform and high, thus obtaining a beneficial effect on increasing the reliability of the explosion. Found. The high density is a particularly important factor for small diameter, low loading and explosive lines. In the combined core, it has previously been known that internal reinforcement at the center is preferred for high loading lines made of self-supporting explosives (see US Pat. No. 3,338,764).

It has been found that in the case of a low loading line having a core according to the present invention, it is important to arrange external reinforcing filaments for proper function. In addition, when reinforcing the combined explosive core of the dopant produced by the method of the present invention, it is preferable to arrange an external reinforcing material such as, for example, parallel to the longitudinal direction of the dopant. Such dopants are more suitable to be produced in a continuous process at high speeds compared to conventional low energy dopants using woven or wound fabric reinforcements.

The explosive bond composition constituting the explosive core of the dopant is at least one fine crystalline high performance explosive compound that is sensitive to the primer (e.g., organic polynitate such as PETN or mannitol hexanitate, or cyclotrimethylenetrinitramine (RDX)). Polynitramine, such as cyclo tetramethylenetetranitramine (HMX), and the like. Among them, PETN is the most readily available and satisfies the conditions most commonly encountered in explosive work, and for this reason, PETN is preferred as a crystalline explosive in the core of the explosive bond.

Crystalline high performance explosive compounds are mixed with binders, examples of which include natural or synthetic organic polymers such as soluble nitro cellulose (US Pat. No. 2,992,087) or mixtures of organic rubber and thermoplastic hydrocarbon resins (US Pat. No. 2,999,743). have. The binder described in the above patent can be used to prepare the dopant of the present invention. Other components may be added to these compositions, for example, additives may be used to plasticize the binder or to increase the density of the composition.

The dopant produced according to the method of the present invention is a low energy dopant, i.e., a dopant that generates relatively little noise and explosive power during an explosion. Thus, the diameter of the core is determined to contain at least 0.1-2 g, preferably at least 0.4 g, of a crystalline high performance explosive compound per meter of core length for a given core composition. For deep trunks with relatively high loadings, noise levels are likely to be a problem in some regions. Below about 0.1 g / m, the new path to full propagation of the blast wave is lowered unless the deep composition includes a high energy binder and / or a plasticizer. In the case of such compositions, such as compositions containing high viscosity nitrocellulose binders plasticized with trimethylolethane trinitrate, particulate high performance explosives in the core can be loaded to as low as 0.02 g / m. As the line width for the lower line or the trunk line, the loading amount of about 0.4-2 g / m proved to be advantageous. In the case of explosive cores with low loadings, such as in the depletion line according to the invention, it is important that the crystalline high performance explosive component be in the "fine" particle size range. In other words, the maximum particle size of the particles should be in the range of about 0.1-50 microns and the average maximum particle size should not exceed about 20 microns. It is not preferable that the explosives have a larger particle size, a greater difference in particle size, or the presence of particulate foreign matter, since it prevents the explosion from spreading uniformly in the core. Suitable explosives for use in the core are those with pores.

The core explosive charge is a function of the crystalline high performance explosive content and core diameter of the bond composition. The content of the crystalline high performance explosive may vary from about 55% to about 90% by weight of the core composition. If the explosive content is low, the diameter of the core is increased to some extent, but the explosive content is as high as possible, which is more efficient and the explosion propagation reliably occurs. Preferred content is at least about 70% by weight of the core composition. When the explosive content is about 55-90% by weight, a core loading of 0.1-2 g / m can be obtained by setting the diameter of the core to about 0.025-0.152 cm. Using a core diameter of 0.069 cm yields a preferred core loading of 0.4 g / m. The explosive composition also includes about 1-10% by weight (preferably 2-5% by weight) of the binder and, if necessary, adds a plasticizer to allow injection of the composition and impart adhesion to the core.

The density of the core varies with the type and amount of particulate explosives and binders used, and the type and amount of other additives. The density of the cores of the compositions according to the aforementioned US Pat. Nos. 2,992,087 and 2,999,743 is about 1.5 g / cm 3. The density of cores of this size has the advantage that it delivers better blast waves compared to only about 1.2 g / cm 3 at the particulate core, and thus the explosion speed is higher for a given diameter. The shape of the core cross section is not very important due to the function of the dopant wire, but it is preferable to use a core having a circular cross section in terms of facilitating the production of the dopant wire.

Cores of combined explosives are protected to prevent wear or damage during handling and preparation for explosive work. If the sheath is mainly used for protection, the thickness should be relatively thin (for example, in the range of about 0.013-0.191 cm), and if the sheath is subjected to significant stress, such as in quarry surface work, the thickness of the sheath may be up to about 0.318 cm. Can also give Uniform protection is difficult when using coatings with a thickness of less than about 0.013 cm. The thickness of the coating according to the method of the present invention does not require a coating larger than about 0.318 cm, and if the unnecessary coating is used, the manufacturing cost of the dopant line is increased, the flexibility is reduced, and it is difficult to load in a small drilling hole. In view of the convenience of use and the degree of protection of the core, a coating thickness of about 0.051-0.127 cm is preferable, and therefore, when the core loading is 0.4-2 g / m and the coating thickness is 0.051-0.127 cm as described above, The loading thickness and the coating thickness and ratio are about 3/1 to 39/1.

In the coating thickness within the effective range, it is better to use a relatively thick coating when the explosive charge amount of the core is near the lower end of the effective range, because the initiation and propagation of the explosion is assured by this. In addition, by increasing the thickness of the coating as the loading of the core increases, the explosion is assuredly continued through the knot and half-hitch.

The sheath only consists of one or several plastics. In other words, all of the layers that make up the sheath are made of plastic and the metal or fabric layer is not contained in the sheath at all or adjacent to the core.

The coating is made of a plastic (i.e., deformable) material having a fluidity that is capable of injecting at temperatures not too high above the melting point of the explosive in the core (i.e., no more than about 75 DEG C. above the melting point of the explosive). In this way, a plastic coating (plastic coating) can be applied to the core by injection or other conventional coating methods without causing deformation to damage the explosive. Plastics must be flexible and tough after being cured. The temperature of the plastic that can be used to coat the core depends on the contact time between the core and the plastic material, the heat exchange rate between the core and the plastic material, and the stability of the binder in the core, but for cores containing PETN At temperatures not exceeding about 20 ° C, the plastic should be fluid. The plastic material may be, for example, a thermosetting material such as rubber or other elastomer, and may be, for example, wax or asphalt or one or several kinds of polyolefins (eg, polyethylene or polypropylene), polyesters (eg, polyethylene terephthalate). ), Polyamides (e.g. nylon), polyvinyl chloride, ionomer resins (e.g. ethylene / methacrylic acid copolymer metal) and the like. Thermoplastic coatings are preferred in view of being readily available or easy to apply, among which polyethylene is particularly preferred.

In order to maintain the structure and size of the dopant when used in the field, it is desirable to increase the tensile strength of the dopant by using a reinforcement and not to break the middle part of the core due to the normal force when loading the drilling hole. Do. Such reinforcement may include fiber strands or the like in the plastic layer of the protective coating or may be arranged around the outside of the sheath, but one or several (preferably 4 or more) continuous fiber strands may be placed around the core. It is more preferable to arrange | position in parallel in the longitudinal direction of a core part by making it contact.

The fiber strands are better disposed between the core and the sheath than are included in the plastic layer of the sheath, to allow less heat to be transferred from the plastic to the core when hot plastic is injected onto the core. As used herein, the term “fiber strand” refers to the fact that a plurality of fibers are twisted together, a plurality of filaments are not twisted and superimposed, a plurality of filaments are somewhat twisted, a strand of filaments (monofilament) is twisted or twisted It means a continuous strand of fiber, filament, or polymer material consisting of one or several strips made of non-twisted, non-twisted platy material such as natural or synthetic polymers. Such fiber strands are secured around the core by plastic covering. Any fiber can be used as long as it has sufficient tensile strength to prevent the explosion propagation from being interrupted due to the force applied when the doping wire is loaded into the drilling hole. In this case, the tensile strength of the core should normally be at least 4.5 kg. To reliably withstand even stronger forces, it is advisable to reinforce the core to have a tensile strength of at least 9.0 kg. Type of fiber The number of filaments, the thickness and the number of fiber strands should be selected to meet these tensile strength requirements. Multifilament fibers are better than monofilaments because the multifilament spreads around the core to provide an insulating effect in the coating operation and also to a wider range of casing effects. In the case of high-strength thread, the number of strands and their thickness can be lowered. Fibers with a thickness greater than 2000 denier are not good because they make the line too thick. Although natural fibers can be used regardless of the type, it is preferable to use synthetic fibers in the form of polyester, polyamide and polyacryl in view of excellent strength. Especially good are all-aromatic polyamides made by condensation of nylon, polyethylene terephthalate, and terephthalic acid and para-phenylenediamine. If the thickness of these fibers is 800 denier or more, the tensile strength is at least 4.5 kg, and therefore, in the wire according to the present invention, a single fiber strand is sufficient. However, multiple layers of fibers are better because they add strength. In addition, the fibers may be used to a smaller thickness, that is, about 400 denier. In a preferred dopant wire produced according to the method of the present invention, at least four multifilament yarns are uniformly arranged around the core portion to uniformly reinforce the core portion. It is not critical whether the multifilament yarns should be laid adjacent to each other prior to coating the plastic sheath on the cage. This is because stretching the cage and coating the plastic coating spreads the filament of the multifilament yarn to mix the fibers around the core. For this reason, and considering the circumference of the core and the thickness of the fiber, etc., it is too much to use more than 12 fibers. In general, the thickness of the filament layer should not exceed 0.025 cm.

Textured yarns or composite yarns are particularly urinary deep reinforcements as long as they are firmly bonded to the surrounding plastic sheath. Applying an adhesive coating such as soft wax to the fiber strands enhances the bond between the fiber strands and the plastic sheath, thus reducing the likelihood of the fibers moving, damaging the core and reducing the peel strength of the sheath. Increases.

Hereinafter, a method of the present invention and an apparatus for implementing the method will be described with reference to FIGS.

2 and 3, the piston type injector 5 has a piston 6 and a cylindrical injection chamber 29, which is wrapped in a heating coil 7. The injection chamber 29 has an exhaust hole 25 and a screen 26, which are provided on one side of the porous support plate 27. The mass 28 of the deformable bond explosive composition is contained in the holes of the injection chamber 29 and the support plate 27. On the other side of the support plate 27 adjacent to the die portion whose diameter in the injection chamber 29 is reduced, the explosive lump 28 is pushed through the die portion by the action of the piston 6 and formed into the core portion 2.

Adjacent to the die portion of the injection machine 5 is a fiber strand array plate 8. The array plate 8 arranges the fiber strands 9 and 10 in an annular parallel manner. The array plate 8 has an axial passageway and a radial groove, which radial grooves receive the fiber strands and meet while forming a curved surface with the axial passageway. The array plate 8 is supported at a position such that when its grooved surface meets the surface of the injection machine 5, the axial passage of the array plate is coaxial with the core 2 emerging from the die portion of the injection machine 5. . The fiber strands 9 and 10 are released from the spools 11 and 12, respectively, by capstans 13, and the winches 13 draw the fiber strands under sufficient tension to move the cage. 14) The core 2 exiting the injection machine 5 is moved into the cage 14 and moved by the cage 14. The winch machine 13 draws the cage 14 in which the core 2 is moved through the injection die 15 of the second injection machine, which coats the plastic 4 around the cage with a plastic material. The injection die 15 has an outer annular portion 17 and an inner tubular portion 16, which are annular portions of the soft plastic material 30 which are conveyed to the die 15 through the wall of the annular portion 17. It is positioned to be a tub between (17) and the opposing surface of the tubular section (16). The cage 14 moves through an axial passageway in the tubular portion 16. The vent hole 18 extends through the wall of the tubular portion 16 and is connected to the axial passage. The tubular portion 16 and the fiber strand array plate 8 are spaced from each other on a common axis, which are connected to each other by a connecting tube 19. The connecting tubing 19 surrounds the cage 14 in the space between the array plate 8 and the tubular part 16. The coated cage containing the core, i.e. the dopant 1 formed at the exit of the die 15, is sent to a tank 20 for curing the plastic coating material. After passing through the winch machine 13, the derailment line 1 is wound up by the winding-up apparatus 22. As shown in FIG. The dose line 1 is easily wound by passing through the tension adjusting device 21. The injection machine piston 6 is connected to the sensing device 23, which detects the speed of the piston and thus sends a signal to the signal processor 24. The signal processor 24 is connected to the drive device of the winch 13 and the drive device of the take-up device 22 to adjust the speed of these drive devices according to the signal received from the detection device 23.

4 shows a variant of the injection die 15 that can be used in the apparatus of the present invention with an injection machine forming an explosive core. Since the injection die 15 includes an apparatus for arranging the fiber strands in parallel in an annular manner, it can be used in the apparatus of FIG. 2 without the fiber strand arrangement plate 8. In this modification of FIG. 4, the directional passage of the injection die 15 includes the cylindrical portion 31 and the circumferential portion 32. The hollow cone insert 33 is positioned so that a small gap between the contact surface at its apex fits within the cone 32 of the die.

The winch 13 pulls the fiber strands 9 and 10 along the inner surface of the adjacent conical insert 33 via a hole in the fiber guide ring 34. The fiber strands are gathered into a conical portion of the insertion portion 33 and are arranged in parallel with each other, and pass through the cylindrical portion of the insertion portion 33 into a cage.

The explosive core 2 is inserted into the cylindrical portion of the insertion portion 33 and is moved into the cage. The plastic material 30 is introduced into the annular passage formed between the wall of the conical insert 33 and the wall of the injection die 15. This annular passage is through the cylindrical portion 31 past the gap between the cone portion 32 and the apex portion of the insertion portion 33. The cylindrical portion of the insert 33 is connected on a common axis with the cylindrical portion 31 of the die. The cage 14 (containing the core) formed in the cylindrical portion of the insertion portion 33 flows through the cylindrical portion 31 from the gap between the cone portion 32 and the vertex portion of the insertion portion 33. When passed into the flow of the plastic material 30, the cage containing the core portion is covered with the plastic material 30 to be formed into the dopant line 1.

The following is a preferred embodiment showing the manufacturing method of the dopant wire of the present invention.

Example 1

A. Referring to FIG. 3, the lump 28 in the injection chamber 29 is 455 g of a deformable bond explosive composition, which contains 76.5% fine PETN, 20.2% acetyltrivthyl citrate, and 3.3 % Nitrocellulose. Fine PETN has pores, an average particle size of 15 microns or less, and all particles are 44 microns or less. By maintaining the temperature of the injection chamber 29 at 63 ° C. by the heating coil 7, the explosive composition inside is maintained in an injectable state. After the explosive composition is placed in the injection chamber 29, the piston 6 is advanced to seal the injection chamber 29 and exhaust it through the exhaust hole 25. Mercury-Maintain vacuum level of 74.2 cm for 1 minute. This is to prevent the entrainment of air in the explosive composition. If air is entrained, discontinuity may occur in the injection core and damage the propagation capability of the explosion. Next, the piston 6 is further advanced so that the lump of mass 28 is compressed only to the extent that no injection is possible.

The fiber strands 9 and 10 and four other fiber strands (not shown) are inserted into the radial grooves of the array plate 8 and the winches 13 are operated to guide the fiber strands to the shaft of the array plate 8. Pass through the directional passage and tubular portion (16). The six fiber strands are each 1000 denier strands made of polyethylene terephthalate fibers, and their tensile force is adjusted to 114 g by the tension control unit 21, respectively. At the same time, the means for moving the collector 22 and the plastic material 30 and the winding device 22 are actuated. Plastic material 30 is a low density polyethylene of 150 ° C. The tank 20 consists of two rooms, the temperature of the water in the first room is 81 ° C., the temperature of the water in the second room is 21 ° C., and the dopant passes through these rooms. This cooling in zone 2 results in a more uniform cooling of the plastic sheath and a more tight coating of the sheath in the cage. The diameter of the part where the core part 2 is formed in the injection machine 5 is 0.076 cm. The gap between the outer annular portion 17 of the die 15 and the opposing surface of the inner tubular portion 16 is adapted to form a polyethylene sheath 4 having a thickness of 0.089 cm.

After operating the winch 13, the tension adjusting device 21, the winding device 22 and the tank 20, the piston 6 is advanced at a speed of 1.270 cm / min. The explosive lump 28 passes through the screen 26 for filtering particles of 0.025 cm or more, and then passes through the holes of the support plate 27 to form a solid core 2 having a diameter of 0.076 cm. The core part emerges from the injection machine 5 at a speed of 75.6 m per minute, and the speed at which the cage is advanced by the winch machine 13 and the winding speed of the take-up device 22 is determined by the signal received from the signal processor 24. To match the speed. By evacuating through the exhaust hole 18 to maintain a vacuum, a plastic sheath is applied to the core-containing cage 14 passing through the tubular portion 16. The vacuum level in the tubular portion 16 is maintained at -15.0 cm of mercury.

The wire 1 wound around the winding device 22 has an outer diameter of 0.254 cm, a core diameter of 0.076 cm, and a polyethylene coating of 0.089 cm. The PETN loading in the core was 0.533 g / m (the ratio of PETN loading and coating thickness = 6/1), and the core density was 1.5 g / cm 3. As shown in FIG. 1, the fiber filaments completely surround the core. This line is flexible, light and has a tensile strength of 45 kg.

When the tip of the No. 6 primer is joined to the exposed end of the bomber on a common axis, the bomber explodes at a speed of 6900 meters per second. The line of application does not detonate itself even if its one end is combined with the other. When you explode a series of bombers, the explosion propagates through various knots. If the primer and the dopant are not on a common axis, the detonation of the dopant line becomes difficult.

B. Instead of the die 15 and the fiber strand arraying tube 8 shown in FIG. 3, the doping wire is manufactured by the method of A described above using the injection die 15 of FIG. Here, the winch 13 draws four fiber strands through the motive portion of the insertion part 33, where the fiber strands receive a sufficient tension to form a longitudinally parallel moving cage. The core is moved into the cage, and the cage including the core is drawn through the flow of polyethylene flowing through the cylindrical portion of the axial passage of the die. In so doing, a soft polyethylene coating is applied around the cage. As in A, the diameter of the core does not substantially decrease during operation.

By appropriately changing the size of the die and the injection speed, it is possible to manufacture the dopant line having different diameters, core thicknesses, number of reinforcing fiber strands, and the like by the above-described method.

The effects of various parameters such as the use of the low energy dopant according to the invention, the loading and diameter of the core, the thickness and composition of the sheath, and the number and type of reinforcing fibers are indicated in the following examples.

Example 2

Example 1A, except that 0.26 g of the fine PETN described in Example 1 was placed in a 0.88 mm thick aluminum shell with a closed bottom, and the tip of the aluminum shell was a 3 m long dopant (PETN loaded at 1.49 g / m and 0.127 cm in diameter). The dopant wire as described above. This line is for trunk lines. The 1.5 m long dopant wire (for the lower wire) described in Example 1A was placed in an aluminum sheath (booster) and brought into contact with PETN. The other end of the lower line is in contact with the impact sensing portion of the impact retarder primer. The trunk explodes into No. 6 primer, where the tip of the primer contacts the exposed end of the dopant on a common axis. The explosion passes from the trunk to the booster, from the booster to the underline, and from the underline to the impact retarder.

Depth line for trunks with core loadings of 2.13 g / m and 0.938 g / m and diameters of 0.152 and 0.102 cm, and for bottom wires with core loadings of 0.638 g / m and 0.469 g / m and diameters of 0.084 cm and 0.07 cm The same result can be obtained by using a doping line.

Example 3

The following experiments show various treatments for knots, tensile forces, abrasion, etc. that the dopant of the present invention can withstand.

A. One end of the 18-meter-long lower-line depot line described in Example 1A is brought into contact with the impact sensing portion of the impact-type delayed brain stem. In a caratridge (a flexible film-tight, compressed at both ends) containing a nonaerated virtual water gel explosive composition, 5 cm in diameter, 41 cm in length, and 0.9 kg in weight. Put the primer. The primer and the dopant are fixed to the film caterine by a hitch. The caratridge is placed in a 15 m deep virtual borehole (inside a vertical steel tube with a diameter of 13 cm), taking into account various conditions that may be encountered in the field. The other end of the bottom line with a loading of 0.53 g / m connects to the booster described in Example 2 and the trunk of 1.49 g / m. After the electrostatic discharge to the pipe under the above-described conditions, the trunk is exploded as in Example 2. After the underline-primer-cartridge assembly achieves the following loading conditions, the underline is completely exploded and then the impact-type delay primer is exploded within a predetermined time.

(1) The caratridge is allowed to descend freely over the entire length of the underline.

(2) Free fall of the caratridge stops quickly every 4.6m.

(3) As the assembly enters the pipe, the depot line moves against the rough edge of the steel pipe.

(4) Conditions (2) and (3) are combined.

(5) A sandbag weighing 3.2 kg shall be placed five times on the assembly in the pipe in each case under the conditions (1) (2) (3) (4) to allow the sandbag to rub the drapery.

B. Tie a knot to the dopant of Example 1A, and hang a 3.2 kg weight at the end. This weight is dropped five times in the middle while dropping into the 15 m pipe of A to allow greater tension on the knot. The five explosive vessels treated as above explode completely at the knot.

Example 4

Using the dopants of Examples 1 and 2, the delivery of an explosive wave to the filling at the bottom of the explosive charge column in the drilling hole is as follows.

That is, six drilling holes having a depth of 7.6 m and a diameter of 7.6 cm are made at intervals of 2.4 m, and each of them is loaded with three (5 × 41 cm) (caratridges) wrapped with an aqueous gel explosive with polyethylene terephthalate. At the bottom of the caratridge in each borehole there is an impact retarder primer, which is connected to the bottomline dopant of Example 1B by the method of Example 2. The other end of each bottom line is connected to the trunk line (including four fiber strands) as in Example 2. When the main line is exploded, the filling in the straight hole explodes in turn from the filling at the bottom to the delay primer. There is no evidence that the column is destroyed.

Example 5-10

A dopant line is made as in Example 1. The core explosive composition consists of 76.1% fine PETN, 20.3% acetyl tributyl citrate and 3.6% nitrocellulose by weight.

Four identical fiber strands are used as in Example 1. The same plastic coating composition as in Example 1 is used. The diameter of the core is injected differently, and the thickness of the coating is also different. The explosion characteristics of the dopant line detonated in the same manner as in Example 1 are shown in the following table.

(a) The detonation bombed only 50% of the experiments and delivered the explosion, but in all other bombing vessels the explosion was delivered reliably.

The above examples indicate that the explosion speed of the dopant ship is within the range of 6900 m / sec ± 5% regardless of the PETN loading amount and the plastic coating thickness. However, in this kind of core composition and coating thickness of 0.112 cm, the reliability of the explosion is slightly lowered when the loading amount of PETN and the diameter of the core are minimum.

Example 11-14

The exposure line of Examples 5-10 is tested for reliability of detonation and propagation at the minimum coating thickness for three different core loading quantities and diameters.

These examples show that as the diameter of the core and the PETN loading increase, the plastic coating has the effect of reducing the detonation capacity and propagation capacity of the dopant.

Example 15

In Examples 5-10, a dopant with a diameter of 0.076 cm in the core is made of different coating materials and thicknesses. All samples (at least 46 m in length) coated with metal salts of low density polyethylene, high density polyethylene and copolymers of ethylene and methacrylic acid (ionomer resins) and coated with thicknesses of 0.051 cm, 0.071 cm and 0.084 cm The use of four and eight fiber strands reliably explodes at a speed of about 7200 m / sec. The temperature of the injection die is 175 ° C. when high density polyethylene is coated and 135 ° C. when ionomer resin is coated.

The minimum tensile strength is 32 kg for all samples made of four fiber strands and 64 kg for all samples made of eight fiber strands. After 2.7 kg of weight was placed at one end of the dopant, the sample was repeated five times by the action of the weight to pull the dopant by gravity onto the concrete block and back to the starting position. Explodes regardless.

Example 16-19

As can occur in the field, the effect of core loading and coating thickness on the action of the depot when knots are formed in the depot is shown in the following table.

(a) during 15 experiments

(b) making a knot under a tension of 4.5 kg and, during five experiments,

These examples show that the explosion in the bombardment line is transmitted through the knot rather than being interrupted in the knot by excessive explosive force. In addition, these examples show that increasing the coating thickness as the explosive charge amount increases ensures the knot passage of the explosion.

Example 20-24

A multifilament strand of polyethylene terephthalate (PET) fibers and aramid fibers made of a polymer made by condensation of terephthalic acid and pata-phenylenediamine with a diameter of 0.76 cm in the core in Example 5-10 (each strand is 1000 By denier). The effect of these variables on the bomber intensity and the ability of the bomber to pass the explosion through the knot are shown in the following table.

(a) during 10 experiments.

(b) in three experiments each with bare knots under tensile forces of 4.5,9.1,13.6 and 18.2 kg, respectively.

These examples show that the saddle strength of the dopant line when given the number of fiber strands of the same thickness varies with the tensile strength of the fiber. In this case, aramid forms a wider tensile line, even with a smaller number of strands than polyester. The practice also shows that by increasing the number of strands of a given fiber or by using stronger fibers, the ability to transmit the explosion through a tighter knot can be increased.

Example 25

A continuous solid core of a binder explosive composition consisting of 75 wt% fine PETN and 25 wt% binder (composed of a copolymer of butadiene, acrylonitrile and methacrylic acid) is made of a condensation polymer of terephthalic acid and para-phenylenediamine Attaches to a single strand of aramid fiber. The core and supporting strands are pulled through a tubular sheathing die to coat a 0.064 cm thick low density polyethylene sheath. The width of the dopant thus produced is 1.49 g / m TETN loading, and when detonated by the method of Example 1, it explodes to about 7000 m / sec, the tensile strength is about 34 kg.

Example 26

Except for the fine PETN 76%, acetyl tributyl citrate 20%, and nitrocellulose 4%, by injecting the deformable binding explosive composition as in Example 1 to make 10 1.2m length line Five are 0.076 cm in diameter (PETN content 0.5333 g / m) and the other five are 0.127 cm in diameter (PETN content 1.49 g / m). The extruded dopant is placed in a low density polyethylene tube having an inner diameter of 0.152 cm and an outer diameter of 0.20 cm. The ratio of the explosive charge amount (g / m) and the wall thickness (cm) of these dopants is 18/1 and 50/1, respectively, and the tensile strength of all the dopant lines is about 4.5 kg.

These dopants detonate with No. 6 primers, the tip of which is in contact with the exposed end of the dopant on a common axis. All bombers explode without breaking, and all plastic coverings are consumed. The average explosion speed for all ten bombers is 7300 m / sec.

In the method of the present invention, the diameter is hardly reduced after the core is formed. This method produces a high density core in which the diameter of the core is not reduced, which is necessary for producing a dopant line having, for example, particulate explosive cores. The fact that the diameter of the seal does not change during the process simplifies the process control to achieve the necessary explosive charge of the final core and also eliminates the possibility of penetration into the core of the surrounding fiber strands.

In the case of a detonation line having a small diameter and a low loading amount in the core, when there are particles of foreign matter such as sand or metal, if the particles are too large, the explosion of the ear canal is prevented. For this reason, an important feature of the process of the present invention is to provide a core explosive composition free of particles of foreign matter by providing particle filtering means in an injection machine for producing the core. Particles greater than about 33% of the core diameter should be removed for cores greater than 0.076 cm in diameter, and 0.013 cm or less for cores smaller in diameter.

When the fiber strands and explosive cores enter the plastic-covered injection die separately as in the present invention, it is common for the cores to be transferred into the cages and then the cages are coated together. However, the formation of the cage and the transfer of the core portion and the covering thereof can be performed substantially simultaneously. The two injection means, namely the deep forming die and the coating die, may be included in separate injection molding machines or may be included together in one common injection molding machine.

Claims (1)

A method for producing a dopant by forming a continuous solid explosive core and applying a protective coating on the core, wherein the explosive core is formed from a mixture of a crystalline, high-performance explosive compound sensitive to a primer, and the fiber strands are drawn under sufficient tension. To form a moving cage of longitudinally parallel fiber strands, allowing the core to be moved into the interior of the moving cage, thereby making the moving cage a carrier of the core, and the core diameter after the core is moved into the interior of the moving cage. A layer of soft plastic material is coated around the moving cage while keeping it unchanged, and the plastic material is cured.

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