Drilling Tool Centralizer for High Speed Core Drilling Rig of Tunnel

Combined with the structure of existing tunnel rig, a new type centralizer device of high speed drilling rig of tunnel is designed. It sets a pre-centralizer device at the position of fuselage near the gripper, which provides a pivot for the high-speed rotating drilling tools through bearing. Meanwhile, it sets a post-centralizer device behind the main axle, which provides a post pivot and coaxial high-speed rotating with chuck. The front and rear centralizer devices and the chunk work together and form steady supporting points, which avoids vibration of drilling tools at orifice and improves the stability of drilling successfully. This new centralizer device was used on ZDY1200G type hydraulic tunnel exploration drilling rig for the first time at Niujiagou Gold Mine. It finished a drilling with diameter of 77 mm and depth of 235.7 m, and it’s coring recovery rate reached to 91.2%. During the whole drilling process with the drill speed from 550 r/min to 980 r/min, this new type of centralizer device can support the drilling tools well, and help it running smoothly.