DOUBLE CORE BARREL Russian patent published in 2003 - IPC

FIELD: mining, particularly, means for core drilling with preservation of formation medium. SUBSTANCE: double core barrel has external body with rock cutting tool. Located in body on bearing of rotation is inner barrel whose external surface has hollow ribs triangular in shape forming external channels. They are communicated with hollow of core receiver at inlet and outlet. Double core barrel has movable piston with sealing member and rod. Movable piston closes core receiver from bottom. Said rod protrudes below edge of rock-cutting tool. Cavities of core receiver and external channels are filled with antifriction isolating substance. Internal barrel has tiers of radial holes communicating cavities of external channel with cavity of core receiver over entire length of core receiver. Tiers of radial holes are spaced at variable intervals. Space between next upper tiers is smaller than between previous ones. Triangular ribs have balls accommodated in rolled-in holes on rib tops and uniformly distributed over their length. EFFECT: higher representativeness and information content of core material due to reduced forces of resistance of core motion in core receiver and prevented wedging-up of core receiver. 2 dwg