RU2110037C1 - Shaped charge and method of its manufacture - Google Patents

Abstract

FIELD: petroleum and gas industries, applicable in shooting-through and blasting equipment. SUBSTANCE: the body accommodates the main charge and intermediate charge of plastic explosive pressed in the cover, both charges are separated by an inert lens. Width δ and thickness A in the zone of contact with the main charge, as well as thickness d_cqv≤Б<d_int;0,5d_cqv<A≤H;d_nb≤δ<0,04d_cov.z on the side of the intermediate charge lens, are selected according relations given in the description. The body accommodates the main charge and lens. The cover diameter exceeds the body diameter in the zone of arrangement of the intermediate charge, the cover is made of plastic material. Then the intermediate charge is pressed in the cover, and the latter is installed in the body with radial squeezing. EFFECT: enhanced efficiency. 2 cl, 4 dwg

Description

 The invention relates to the oil and gas industry, in particular to perforating explosive equipment used in blasting and for perforating oil wells.

 Known cumulative charge (KZ) for punching steel sheets, comprising a housing in which the main explosive charge (BB) and an intermediate charge are placed (part N 0134169, class F 42 B 1/02, EP, published. 13.03.85) . The charges are separated by a screen made of a porous material. They give it such a shape that in the main charge of an explosive, a detonation wave emanating from an intermediate charge always outstrips a shock wave emanating from a screen.

 A known method of manufacturing a cumulative charge (Germany patent N PS 3436934, class F 42 B 1/02, published. 01/09/86 or application N 3742290 Germany, class F 42 B 1,02, published. 06/22/89), which consists in the fact that separately manufactured main and intermediate charges are compressed, covering the barrier. The cavity formed in the main and intermediate charges is filled with a hardening mass in a fluid state. This mass hardens or polymerizes, firmly connecting with the main and intermediate charges.

 The disadvantages of such a device are large dimensions and weight.

 The disadvantage of this method is that it is impossible to avoid the displacement of parts relative to each other, which leads to the destruction of explosives during transportation.

 Known cumulative charge, the closest in technical essence and the achieved result, containing a housing in which the main explosive charge with a lined recess and an initiating detonator are placed [1]. The cumulative charge also contains an intermediate explosive charge made in the form of a film. An inert lens is mounted between the main and intermediate charges to form a ring-shaped initiation zone. Considering that the main explosive charge is made of a powerful explosive, for example, based on HMX, and has a relatively large critical diameter of detonation, with a thin intermediate explosive charge, an unstable detonation transfer or destruction of the main explosive charge without detonation transmission, as well as uneven propagation of the detonation front along the intermediate charge of explosives.

A known method of manufacturing a cumulative charge, including the placement in the body of the main explosive charge and lenses, pressing in the cover of the intermediate explosive charge and the subsequent installation of the cover in the housing, after which the flanging of the housing relative to the cover. [2]
This method of assembly does not allow to achieve the necessary alignment of the elements of the cumulative charge, and therefore high charge efficiency.

 The objective of the invention is to create charges with reduced overall weight characteristics and increase their manufacturing accuracy, and hence the effectiveness of the action.

 The technical result of the proposed solution is the symmetrization of the detonation front on the explosive charge and increase the manufacturability of the manufacture of a cumulative charge.

The technical result is achieved by the fact that in the known cumulative charge, comprising a housing in which the main and intermediate explosive charges are separated by an inert lens, the intermediate charge is made of plastic explosive. Moreover, its width B and thickness A in the zone of contact with the main charge, as well as its thickness δ from the side of the lens are selected from the following relations:
d _cr ≤ B ≤ d _pr ;
0.5 d _cr <A ≤ H,
d _ne ≤ δ <0,04d _KZ,
Where
d and d _{straight cr} - a critical and limiting the diameters of the main explosive charge;
d _KZ - the diameter of the main explosive charge;
d _PV - the maximum diameter of the intermediate explosive charge;
H is the thickness of the lens.

 In the known method of manufacturing a cumulative charge, comprising placing the main explosive charge and lenses in the housing, mounting an intermediate explosive charge into the cover and then installing it in the housing, the cover is made of an elastic material with a diameter exceeding the internal diameter of the housing in the intermediate charge placement area and installed in case with radial crimping.

 The manufacture of an intermediate charge from a plastic explosive allows it to be shaped without breaking, which allows detonation to be transmitted from the initiation source to the main charge with a thin intermediate explosive charge.

The choice of the thickness δ of the intermediate charge from the side of the lens in the above ranges is due to the physical features of the detonation process. The stability of propagation of the detonation front at its maximum speed is ensured starting from a certain size (diameter or thickness), which is different for different explosives. With decreasing thickness, the detonation velocity decreases and begins to depend both on the thickness and on the conditions of unloading (expansion) of the detonation product, therefore, the maximum front symmetry will be ensured for δ ≥ d, _etc. The upper limit of the thickness is selected from the conditions for obtaining significant advantages in reducing the thickness and weight of the intermediate charge with a stable propagation of the detonation front. The width B and thickness A of the intermediate charge in the contact zone with the main charge are selected from the following considerations: behind the front of the detonation wave at a speed D (see Fig. 2), the explosion products are unloaded at a speed D / 2 (when it flows into air, i.e. without taking into account the bottom mass), therefore, to ensure reliable excitation of detonation of the main charge, it is necessary to load the explosion of the annular zone B with a width B ≥ d _{cr of the} main charge until the unloading wave in the intermediate charge arrives at point D of the beginning of the load. An increase in the width B greater than d _pr may lead to a decrease in penetration due to a decrease in the diameter of the lens. The implementation of the cover of elastic material can improve the manufacturability. The blank from the plastic explosive is displaced toward the thickened intermediate charge and extends the elastic wall of the lid to the side until it abuts against the matrix wall in the press tool at the time of pressing the intermediate explosive charge into the lid, because the matrix can be made accurately, then the maximum alignment of the base surfaces and the holes for the installation of the means of initiation is ensured. The diameter of the lid exceeds the diameter of the casing, so the lid is pressed into the casing without a gap, radial crimping gives maximum alignment. The load forces P≈ 10-10 kg / cm ^{2 are} sufficient for a snug fit of the K3 elements. The ability to install an intermediate explosive charge is thus achieved using a plastic explosive. At the same time, the cover additionally performs the function of increasing the safety of the assembly, since eliminates the penetration of explosives into the gaps.

 In FIG. 1 shows a diagram of K3; in FIG. 2 - contact zone of the intermediate explosive charge with the main and the lens; in FIG. 3 - installation of the cover in the housing; in FIG. 4 - a press tool at the time of completion of pressing in the explosive distribution charge into the lid.

 Scheme K3 includes: 1- housing; 2 - the main charge; 3 - a lens; 4 - intermediate charge; 5 - a cover; 6 - bottom; 7 - a clamping nut; 8 - matrix; 9 - a punch; 10 - supporting disk.

 An example of a specific implementation of the proposed solution can be K3, including a housing 1 made of aluminum with a diameter of 130 mm, in which the main explosive charge 1 based on HMX d = 123 mm and an intermediate charge 4 of a plastic explosive based on a heating element are installed. Its thickness δ from the side of the lens 3 is 1 mm. Thickness A in the zone of contact with the main charge of 4 mm, width B in the zone of contact - 3 mm. The cover 5 is made of thin-walled elastic plastic. The lens is made of resiliently compressible material. The press tool on which the charge is made includes a matrix 8, the axial guide of which passes through the holes of the charge cover 5 and enters the hole of the punch 9. The blank from the plastic explosive (in the form of a sheet) is forced out towards the thickenings of the charge 4 and distributes into the sides of the elastic wall of the lid until it abuts against the wall of the matrix 8 with a diameter greater than 0.1-0.3 mm of the diameter of the housing in the charge placement zone 4. Since the matrix 8 can be made very accurately, especially when machining the inner surface in one installation, independently This is due to the fact that the diameter of the cover 5 is made of elastic plastic (allowing deformation without destruction) such as polyethylene, polyamide cannot be exact, maximum alignment of the base surfaces and the holes for the initiator installation is ensured. The charge is ejected through the support disk 10 by the ejector pins entering the bottom hole of the matrix 8.

 The cumulative charge works as follows.

 From an initiator explosion, an intermediate charge 4 detonates, in which a symmetric detonation wave is formed, initiating the main charge 2, during the operation of which a cumulative jet is formed, which provides a cumulative charge driving effect.

 A method of manufacturing a cumulative charge includes placing in the housing 1 the main charge 2 and the lens 3 (glued with epoxy glue).

The equipment for the cover is as follows:
the blank from the plastic explosive (in the form of a sheet) is forced out by the press tool in the direction of the thickened intermediate charge 4 into the cover 5 and distributes the wall of the cover to the sides until it fits against the wall of the matrix of the press tool with a diameter exceeding the diameter of the housing 1 by 0.2 mm. Then, the cover 5 with the intermediate charge 4 pressed into it is pushed out and installed in the housing 1 without a gap. Thus the upper portion of the housing 1 make symmetrical crimp, P≈ 10-10 kg / cm ^2, thereby achieving a tight fit and K3 elements ensures maximum alignment. A hole is made in the cover 5 for mounting the initiator.

Claims (2)

1. Cumulative charge, comprising a housing in which the main explosive charge (BB) is placed, an inert lens and a cover with an intermediate explosive charge pressed into it, characterized in that the intermediate charge is made of a plastic explosive, with its width B and thickness A in the zone of contact with the main charge, as well as its thickness δ from the side of the lens, are selected from the following relations:
d _{to p} ≤ B ≤ d _{p p} ;
0.5d _{to p} <A ≤ H;
d _ae ≤ δ <0,04d _KZ,
where d _{to p} and d _{p p} - critical and limit diameters of the main explosive charge;
d _{to s} - the diameter of the main explosive charge;
d _{p . in} - the maximum diameter of the detonation of an intermediate explosive charge;
H is the thickness of the lens.  2. A method of manufacturing a cumulative charge, comprising placing the main charge of explosive (BB) and lenses in the case, pressing the intermediate charge of the explosive into the cover with its subsequent installation in the case, characterized in that the cover is made of an elastic material with a diameter exceeding the internal diameter of the case in zone of placement of the intermediate charge, and installed in a housing with a radial crimp.

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