Detonator • blasting cap

Detonators are used to detonate high explosives. Stab detonators are initiated by sharp firing pins and are used in explosive trains of different types of fuses. Flash detonators are initiated by flames produced by safety fuses, primers, or delay elements. A special type of flash detonator ignited by the flame of a safety fuse is called a blasting cap. Detonators are primarily composed of three types of explosives including sinoxid mixtures, lead azide-based mixtures, and mercury fulminate-based mixtures. 

Pentaerythritol tetranitrate (PETN) is a colorless crystalline solid that is very sensitive to initiation by a primary explosive. It is a powerful secondary explosive that has a great shattering effect. It is used in commercial blasting caps, detonation cords, and boosters. PETN is not used in its pure form because it is too sensitive to friction and impact. It is usually mixed with plasticized nitrocellulose or with synthetic rubbers to form PBXs. The most common form of explosive composition containing PETN is Pentolite, a mixture of 20 to 50% PETN and TNT. PETN can be incorporated into gelatinous industrial explosives. The military has in most cases replaced PETN with RDX because RDX is more thermally stable and has a longer shelf life. PETN is insoluble in water, sparingly soluble in alcohol, ether, and benzene, and soluble in acetone and methyl acetate. 

T. J. Mulqueeny, 50, 9742 (1956) Claims Ignition comps of the Pb-Se type, where the PbO is produced in situ, were prepd evaluated for use in blasting caps detonators. This type of mixt afforded less erratic firing times than when the PbO was mechanically incorporated. The Pb is oxidized by heating in an internally baffled rotating drum in an oxidizing atm USP 2740703 (1956)... 

Low Explosives (such as Black Powder, described in Ref 1, pp B165-R to B177-R) are initiated by Fuses, Squibs and some Blasting Caps. High Explosives are initiated by Electric Blasting Caps, Detonating Cords (such as Primacord Bickford) and by Detonators... 

The Nobel family suffered many set backs in marketing nitroglycerine because it was prone to accidental initiation, and its initiation in bore holes by blackpowder was unreliable. There were many accidental explosions, one of which destroyed the Nobel factory in 1864 and killed Alfred s brother, Emil. Alfred Nobel in 1864 invented the metal blasting cap detonator which greatly improved the initiation of blackpowder. The detonator contained mercury fulminate [Hg(CNO)2] and was able... 

Blasting caps and detonators, test of see Esop s test for efficiency of detonators 1 XI Grotta s test for detonators 1 XV Initiating efficiency of initiating expls, blasting caps detonators 1XVII... 

To initiate the nitroglycerine, detonators filled with black powder were used at first. Later, Nobel [4] invented blasting caps (detonators) charged with mercury fulminate for this purpose. 

In the US modification of Hess test, which has been used by Bureau of Mines under the name of Compression Test with Small Lead Block, one lead block is used. It is 38mm in diam 64mm thick and is placed upon a rigid steel support imbedded in concrete. The block is covered with a disk of annealed steel, 38mm in diam 6.4mm thick. On top of the disk is placed a lOOg charge of expl to test, provided with a No 6 blasting cap. Detonation of the expl compresses the block appr proportionally to the brisance of expl (Ref 6 pp 107-08)... 

Ref 2 describes a Detasheet flexible expl, designated as EL-506, which can be cut to fit any configuration. This expl is reported to meet the requirements of Ref 1 listed further. It detonates under water w/o the use of a protective covering it is extremely insensitive to shock, such as by bullet impact, yet a std blasting cap detonates it. In tests it was fired at pressures of more than llOOOpsi, equivalent to depths of more than 2500 inches. Detasheet EL-506 was stored at. temps from -40°F to 165°F and retained its flexibility under chese conditions... 

Figure 95. Blasting Caps. Detonator crimped to miner s fuse. Compound detonator. Compound electric detonator.

Delay Element. This term may also be applied to a component which provides a specific delay in a blasting cap, detonator, fuze, etc Refs l)0hart (1946), 20 278 2)H.M.Kerr C.R.Hall USP 2560452 (1951) CA 46, 1259 (1952) [Delay elements for electric blasting caps consist of homogeneously mixed powdered metals (such as Mg, Al, Ni, Zn), fuels (such as Si), oxidizers (such as Pb C ) and Misch -metall . By varying the compns, burning times of 15 to 579 milliseconds were obtained] [The Misch-metall (Ger for mixed metal ) is an alloy of rare earths of the following compn ... 

Detonation, as described earlier, is a process where upon a matrix of uniform particles of gas and solid forms a pressure wave. The pressure wave is what causes the bulk of destruction. However, it should be noted that detonation is a completely different process then deflagration and combustion. As previously stated, compounds that detonate must poses certain functional groups. These functional groups are initiated by molecular shocks generated by blasting caps, detonators, and/or boosters. Of coarse not all explosives need to be initiated by blasting caps, detonators, and/or boosters for example, primary explosives (which you will learn much about shortly) can be detonated under relatively easy means by sparks, heat, friction, percussion, fire, and shock. 

Lead azide forms needle like crystals, or a white powder. It begins to decompose when heated to 250 Celsius, and explodes when heated to 350 Celsius. Lead azide is more stable then mercury fulminate, and is an outstanding booster or transfer explosive found in blasting caps, detonators, and fuses. The salt is insoluble in water, but soluble in acetic acid. Lead azide is a standard military initiating explosive (mixed with dextrose to desensitize it). ... 

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