| 摘要 |
<p>Apparatus for drilling a bore hole comprises a hammer (3) and a series of dual wall drill tubes (2). The hammer (3) is supplied with compressed air and is for use in applying successive percussive blows to a percussive drill cutting bit for taking core samples from the bottom of the bore hole while drilling same. An upstanding rig (37) is provided at surface level to support the hammer (3) and drill tubes (2) and to transmit push-down or pull-up movement thereto. First means (32) indexes rotationally the bit for drilling purpose and is operable by a portion of the supply of air. Second means conducts from the bottom end of the bore hole that portion of air used by and exhausted from the percussive cutting bit (27) and having core particles entrained therein. Third means comprises an annular flushing jet (7) to direct a portion of air upwardly through a sampling tube (6) co-axial with the drill tube (2) and hammer (3) to induce a venturi to assist in conducting core particle entrained exhaust air upwardly.</p> |
