Detonator conductive mix

Miniature Conductive Mix Detonator. Since conductive mix detonators would have no bridge wire, which is a delicate and expensive step in the manuf of bridge wire detonators, it has been proposed that conductive mix detonators would provide an attractive alternative... 

Three conductive-mix detonators are shown in Figure 4. Since lead azide is an electrical insulator, a conductant is added, and flake conductants have been observed to be more effective than other particle shapes. A typical mixture contains 95% lead azide and 5% flake graphite. This type of detonator fires rapidly with low energy input for example, the E.I. duPont de Nemours Company s product, designated X811, fires in 4 msec when initiated by a 2.2 uF... 

Figure 4. Lead azide in conductive-mix detonators [1] (a) annular gap (all fire 50 V on 0-015 mF) (b) axial gap (all fire 10 V on 2.2 mF) (c) radial azide colunm (all fire 5 V on 33 mF).

R. M. Ferguson, Development and Design of Conductive Mix Detonators, Canadian Arsenal Ltd. Report 627-1, St. Paul L Ermite, Quebec, Canada, 1974. 

Lead azide is not readily dead-pressed, ie, pressed to a point where it can no longer be initiated. However, this condition is somewhat dependent on the output of the mixture used to ignite the lead azide and the degree of confinement of the system. Because lead azide is a nonconductor, it may be mixed with flaked graphite to form a conductive mix for use in low energy electric detonators. A number of different types of lead azide have been prepared to improve its handling characteristics and performance and to decrease sensitivity. In addition to the dextrinated lead azide commonly used in the United States, service lead azide, which contains a minimum of 97% lead azide and no protective colloid, is used in the United Kingdom. Other varieties include colloidal lead azide (3—4 pm), poly(vinyl alcohol)-coated lead azide, and British RE) 1333 and RE) 1343 lead azide which is precipitated in the presence of carboxymethyl cellulose (88—92). 

This primary explosive is created by adding lead acetate to a solution of sodium or ammonium azide. Lead azide has a good shelf life in dry conditions but is unstable in the presence of moisture, oxidizing agents, and ammonia. It is less sensitive to impact than mercury fulminate, but more sensitive to friction. Since lead azide is a nonconductor, it may be mixed with flaked graphite to form a conductive mixture for use in low-energy electronic detonators. 

Price et al (Refs 14i 14j) conclude from their data that 2,4-DNT should be characterized as an expl. They state that it is a group 1 expl that can be dead pressed with moderate ease that its infinite diam deton vel is approximated by Dj (mm/microsec) = 1.96+2.913(d) (see Fig 1) and that the detonatability and shock sensy of 3 and 10 micron 2,4-DNT are near those of prodn lots of high bulk d Nitroguanidine and DATB Rontsch (Ref 14q) claims that safety in production of expls contg DNT is greatly enhanced when the mixing operation is conducted as follows The components of the expl are placed... 

W.E. Wales D.J. Nagy, USP 3465674 (1969) CA 71, 103744r(1969) (Expl compns with delayed action are described. They may be used to generate sudden pressure, initiate a mech action, or detonate an expl, particularly where it is desired to have a known short delay betw action and reaction. A series of tests was conducted wherein Ig of an N-halo amide was mixed with a small amt of iso-PrOH and the interval betw mixing and expln measured. Mixts of Ig trichloroiso-cyanuric acid and 0.05, 0.10, and 0.15ml iso-PrOH exploded after 15, 17, and 6 sec, resp Mixts of Ig dichloroisocyanuric acid,... 

Hydrogen-air-steam combustion experiments have been conducted to simulate local detonations in a nuclear containment and to validate the respective numerical detonation codes. Experimental facilities used were the Battelle model containment and the containment of the decommissioned HDR in Germany as well as one-compartment vessels at Hanford and Nevada Test Site in the USA or the RUT facility in Russia. Many codes have been developed to simulate the transport, convective mixing, and combustion of hydrogen in a containment building. State-of-the-art are CFD models or lumped parameter models with successful reproduction of, e.g., thermal stratification phenomena. 

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