Electromagnetic and electrostatic insensitive blasting caps, squibs and detonators
OwnerPaul W. Proctor, Robert L. Dowinventors
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Abstract
A broad band attenuator having a ferrite material for absorption of stray electromagnetic radiation minimizes the unintentional initiation of electroexplosive devices. In one embodiment, each input lead of a detonator passes through a ferrite choke core in contact with the metallic casing that houses the detonator. A printed circuit tape between the input leads and the casing provides electrostatic protection, and heat generated by the ferrite choke core is removed by radiation from the metal casing.
Claims8
An electroexplosive device protected against premature initiation from electromagnetic radiation comprising:
- a conductive housing having an upper portion and a closed lower portion wherein said lower portion contains an explosive train comprising an ignition mix, a primer, and a base charge;
- an insulating plug contained in said housing having mounted therein a pair of conductors extending into said lower portions;
- a bridgewire coupled between said pair of conductors and imedded in said ignition mix;
- attenuator means formed of a lossy ferrite material contained within said housing and spaced from said insulating plug, said ferrite material having a Curie temperature greater than about 150.degree. C. and said attenuator means being configured to receive said conductors therethrough;
- and
- nonconductive seal means mounted within the upper portion of said housing and extending therefrom, wherein said conductors pass through said seal means for coupling to a source of power for initiating said device.
In an electroexplosive device including a metal housing and a at least one conductor coupled to an igniter, an electromagnetic radiation and electrostatic charge protection device comprising:
- an electromagnetic attenuator spaced from said igniter in physical contact with said housing and configured to receive said at least one conductor therethrough, wherein said attenuator is formed of a lossy ferrite material having a Curie temperature greater than about 150.degree. C.;
- and
- capacitive tape means coupling to said at least one conductor and to said housing wherein said tape means is mounted within said electroexplosive device intermediate of said attenuator and said igniter.
Dependencies are inferred from the claim text.