Delay electric igniter

Often another controlled volume of low explosive is placed between the matchhead and the primary charge. This bums for a specified period introducing a delay (from a few milliseconds to a few seconds) into the detonator. However, any low explosive delay device syn. delay electric igniter) introduces imprecision because the chemicals are affected by moisture, temperature, and time. High precision delay electric detonators implant the match-head directly into the primary explosive and control the delay with an integrated circuit within the detonator. 

Each water resistant tubular unit contains an open ended piped match holder, a time delay element and a holder at the opposite end of the tube for an electric igniter (or a second PYROCLOCK element). 

Ger 9-10 (Antiwithdrawal fuzes) Ger 20 (Bomb high-explosive train) Ger 33 (Delay compns) Ger 33-34 (Delay elements) Ger 34-35 (Detonators blasting caps) Ger 38 39 (Dust fuze) Ger 40-41 (Electric fuzes) Ger 41-2 (Electric igniters and primers) Ger 42 (Electric matchhead) Ger 44 (Eschbach igniter) Ger 53-54 (Fuseheads and their manuf) Ger 54-56 (Bomb fuzes) ... 

Ignition Delay. If the igniter is of the delay type, it is necessary to determine the time elapsed from the start of current flow to the rupture of the igniter case. For instance, the M12 electric igniter has an ignition delay not exceeding 100 milliseconds (Ref 2)... 

The electrical energy is rapidly transformed into thermal energy, and because the temperature of the ionized gas is generally above 300 K, the ignition delay time is short compared with the spark duration, . Ignition only takes place if the electrical energy exceeds the critical value, and if this energy is... 

Altman and Nichols (A4) were the first to test the constant ignition-temperature approach experimentally. These investigators ignited samples of double-base propellants with electrically heated wires located on the propellant surface. The ignition delay was measured from the time of application... 

Many other methods of making lead azide in a safe form have been described, but the only one to have found commercial importance consists of replacing the dextrine by a small proportion of gelatine. When properly made this form of lead azide is as safe to handle as the dextrinated form and has improved sensitiveness to flame. It can therefore be used by itself in electric and delay detonators, but not in plain detonators as it is not ignited with certainty by safety fuse. 

Plastic Igniter Cord (PIC) is a modern version of quickmatch in which the gunpowder is replaced by a delay composition, consisting essentially of lead dioxide and silicon, while the support material is aluminium or iron wire. A plastic tube encloses the fuse, as in the manner of electrical... 

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