Standard detonators

The destruction of fuzes and supplemental charges has changed. Instead of using a standard detonation chamber, they are simply placed in the MPT and allowed to decompose or detonate. At the same time, the MPT design has changed—it now uses a steam-heated industrial oven with internal steam recirculation, which has not been demonstrated for destruction of fuzes and supplemental charges. 

To determine the sensitiveness to detonation of mining explosive in some countries (including Poland) special standard detonators have recently been introduced, containing 0.05, 0.1,0.t5, 0.20 g etc. of silver azide. The stronger contains 0.60 g of silver azide or an equivalent quantity of lead azide. 

To compare the performance of K2DNABT with that of lead azide, 40 mg of K2DNBT was loaded in a small aluminum holder and 1 g of RDX was pressed in a standard detonator copper shell. This was initiated by an electrical igniter. The... 

Figure 060. Standard detonating cord. See TM 43-0001-38 for additional information.

Figure 1.2. Some types of detonators (a) stab detonator (b) blasting cap (standard detonator)...

The methods described below are primarily intended for sensitivity testing of an explosive to the standard detonator, the blasting cap. The tests are also known as cap sensitivity tests. 

The cap sensitivity tests described here are based on the initiation of a high explosive charge by the standard detonator. The effects of the detonation of the explosive charge on a lead cylinder, steel plate, or steel tube are observed. On the basis of these effects, the conclusion about the completion of the detonation... 

Donor, acceptor, and control charges are placed along the same axis on a 700x 700x100 mm steel plate (Figure 2.32). When the distance between the donor and the acceptor charge is adjusted, the initiation of the donor charge is performed by a standard detonator. 

The lead plate test setup is presented in Figure 2.39. The plates used in the experiment are made of unalloyed lead, 30-40 mm in diameter and 1.5-5 mm thick, as required for a given detonator type. For example, the No. 8 standard detonator should cut a clean hole through a 5 mm thick lead plate. 

The initiation of the booster is performed by the standard detonator. Evaluation of Results... 

Two holes are made in the previously prepared cylindrical explosive charge, given as points A and B in Figure 4.3, where the ends of the detonating cord are inserted. The ends may be capped with standard detonators before being inserted into the explosive charge. The distance between point A and point B equals 300, mm and it is actually the length at which the detonation velocity... 

If the explosive charge is taken by a volume of 10 cm, it is to be prepared in a special device illustrated in Figure 5.3 as follows. A trapezoidal piece of 10 pm thick tinfoil (Figure 5.4) is wound around the piston, and the projecting part of the tinfoil is folded down onto the end of the piston, forming a tube. Then the end of the piston is inserted into the matrix together with the so-formed tinfoil tube. TTie matrix is clamped by means of the frame, and the piston is withdrawn slowly from the tinfoil tube. At the bottom of the tube, a hole is pierced by means of a wooden rod, and a standard detonator is inserted so that it projects 12 mm from the base piece of the device. 

If necessary, because of the safety requirements, during the charge preparation procedure, the detonator may be replaced by a metal cylinder of the same size as a standard detonator. The detonator is inserted into the explosive charge shortly before the testing. 

The cylindrical explosive charge, 41 mm in diameter and 200 mm high, is placed onto a 152x152x51 mm steel witness plate. The plate is made of steel having a Rockwell hardness in the range from B-74 to B-76. The explosive charge and the witness plate rest on a massive steel base. The initiation of the explosive charge is performed by means of a standard detonator and a booster. 

A comparative method uses a standard detonating fuse with known VOD. A fixed known length of the standard fuse is placed in a parallel loop with the test explosive. The two ends of the standard fuse are in contact with the test explosive and when detonated will ignite both standard and test explosive. The larger path of the standard fuse means that the start and end parts both ignite, causing the two flame fronts to meet at a point which is identified by an indentation on a lead plate adjacent to the standard fuse. The VOD of the sample can be calculated from the distances and the VOD of the standard explosive (see Exercise 14.10). 

The influence of the specific surface of the primary explosives on their initiation efficiency has already been included in the graphs above as reflected by their compaction behavior. It was further studied in a standard detonator number 3 cap with 0.35 g of TNT compressed by 76.5 MPa as a secondary charge [9]. LA was compressed by 13.8 MPa without any reinforcing cap while MF and DDNP were compressed by the same pressure with a reinforcing cap. The results are shown in Fig. 2.10. Both DDNP and LA show a performance relatively independent of speciflc surface with the best performance around 4,000 cm g The behavior of MF is however quite different, as its minimal necessary amount continually increases with increasing specific surface (decreasing crystal size). 

The incompatibility of LA and copper is the reason why it could not be used directly in detonators with the otherwise very popular copper tubing [70]. This, however, does not mean that LA could not be present inside a copper tube detonator. Many designs have been developed in which LA is encapsulated inside a protective tube made of compatible material and inserted into the copper tube of a standard detonator. The tin, zinc, or silver coating may also be used in some special applications. 

It can be exploded by a standard detonator (i.e. with activator such as Azides, Peroxides, RDX). 

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