Abstract:
Detonator is an explosive element which is used in various devices for the initiation of high explosives and classified according to their external initiation mechanism. Hot wire detonator is initiated thermally by electrical means.
Function time is one of the important performance parameters of the detonator. It is very critical, especially, where synchronization is required in explosive bolts, during release of several motor ports, in multipoint initiating devices, blasting mines etc.
The objective of the project is to study the effect of primary charge load pressure on function time, measured using photo diode sensor and oscilloscope, of a hotwire detonator taking Dextrinated Lead Azide as primary charge and PETN as intermediate and base charge. The project also includes the experimental studies of the variation of function time depending on the nature of the primary charge. Behavior of Lead Styphnate and Lead Azide were compared.
When the load pressure on the primary charge filled in the flushed wire-bridge detonator was increased, results showed that function time and dispersion decreased. In case of DLA it was observed that it became insensitive at 80 Mpa whereas Service Lead Azide remained sensitive even at 300 Mpa. Nature of primary charge also has significant effect on the function time.
In the light of these results, function time of a hot wire detonator can be decreased, made precise and reproducible, and also, at the same time, no fire capability at safe current can be improved with increase in primary charge load pressure to meet specific requirements.
