Deep well drill rig - with friction wheel producing sparks for combustible gas explosion effecting percussive drilling action

摘要

The Parent Patent No. 2726729 described a deep well drill rig in which a percussive action is achieved by the detonation of explosives or of a combustible gas. The spark plug for firing is now replaced by a friction spark wheel which is driven by contact with the borehole wall. An electrode which receives an electrical current through a cable from the surface is in contact with a driven serrated wheel to produce the ignition sparks. This needs no high-tension supply like a spark plug so that the rig can now be operated for offshore well drilling without endangering the personnel.