High temperature and pressure igniter for downhole percussion coring guns

Abstract From the Canadian patent

An igniter is set forth in the present disclosure for use with a coring gun assembly. A bullet equipped with a bottom and having an O-ring thereabout is positioned in a chamber at one end thereof for firing to take a core sample. At the opposite end, an igniter is positioned in the chamber resting primarily on a shoulder aligning an elongate cylindrical shell within the chamber and having an external O-ring for sealing purposes. An elongate electrically insulated conductive firing pin extends through said shell so that an external circuit can be connected thereto to create a firing pulse. The current flows through the pin and through a bridgewire disc positioned at the end of the pin which …