Igniter with static discharge element and ferrite sleeve

Claim 1

An electroexplosive device comprising: (a) an electrically conductive casing having an opening therein; (b) a heat ignitable charge in said casing; (c) means for igniting said charge including a bridge element in proximity with said charge and conductor means comprising at least one lead for supplying an electric current to said bridge element; (d) a static discharge element for preventing accidental electrostatic discharge of said device, said element comprising a nonconductive substrate having an opening therein to permit said conductor means to extend therethrough, a thin electrically conductive layer covering a portion of at least one face of said substrate, said conductive layer being in electrical contact with said casing but out of contact with said opening means and said conductor means, said conductive layer have a boundary, a portion of which is disposed in proximity with but entirely out of contact with the adjacent edge of said opening, whereby a spark gap is provided between said lead wires and said conductive member; and (e) a ferrite sleeve having opening means extending longitudinally therethrough to permit said conductor means to extend therethrough, means for insulating the sleeve from said conductor means, and means for providing electrical contact between the sleeve and the casing.