DUAL CORING TUBE FOR INCLINED DRILLING Russian patent published in 1997 - IPC

FIELD: drilling equipment. SUBSTANCE: this is intended for core taking in prospecting drilling. Dual coring tube has inner tube which is connected with outer tube by means of ball and/or roller or needle roller bearing. Holding spring and inner surface of inner tube have antifriction coating. Set of stabilizing components is distributed along outer tube for stabilization of inner tube. Tapered shoe of inner tube has lower bevelled edge. Coring tube is provided with indicator of core wedging in inner tube, and sealing unit with ball and its detent to ensure sealing of inner tube of coring arrangement. Aforesaid configuration enhances rigidity of inner tube and prevents its rotation together with outer tube. EFFECT: high efficiency. 2 cl, 7 dwg