Importance

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Abstract

Improved uniformity of timing, and particularly reduced sensitivity of timing to minor variations in delay charge size, are achieved in delay detonators by placing a loose load of a flame-sensitive ignition composition between a pressed delay charge and an ignition assembly, e.g., a percussion primer, at the actuation end of the detonator. The loose ignition charge has a free surface and is adapted to be ignited in response to direct contact with flame emitted from the ignition of a charge in the ignition assembly. Preferably, the delay charge is pressed into a plastic carrier which, in a non-electric detonator, has an open end terminating between the walls of the detonator shell and a primer shell that closes the actuation end of the detonator, and the ignition charge is loosely loaded into a metal capsule seated against the delay charge.

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First Claim