CRYOGENICALLY COOLED DRILL

摘要

This discloses a drilling unit in which the drill bit mechanism is placed at the end of the rotor shaft of a motor either by direct attachment to the shaft or by gear. Cryogenic cooling is provided by sending cryogenic fluid into the rear portion of the motor and causing it to flow toward the front end of the motor for cooling the motor, effluent from the motor being conveyed into and through the drill bit and through bearings and gearing, for cooling and cleansing. The coolant effluent from the drill bit mechanism and motor passes into the bore hole thereby cooling it and carrying cuttings and debris upwardly through the hole.