| 摘要 |
Coring apparatus (1) for the recovery of a solid bar of rock formation being drilled comprises concentric inner and outer barrels (2, 3) arranged so that the outer barrel (3) can be rotatably driven relative to the inner barrel (2). The outer barrel (3) carries a core head (11) and bearing means are provided for the barrels (2, 3) comprising a first bearing (13A/B) supported in said core head (11) and a second bearing (14A/B) spaced from the first in a top head part (15, 18) of the apparatus, the arrangement being such that the inner barrel (2) can be located simply in the outer barrel (3) by landing the foot of the inner barrel (2) on said first bearing (13A/B). Adjustment means (14) in the top head part (15, 18) caters for axial irregularities between the barrels. The outer barrel tubing (6) has a minimum inside diameter of about 7 ins. (17.78 cm) and EI value in the range 5.94 x 10<9> lb. in.<2> to 9.77 x 10<9> lb. in.<2> (17.383 x 10<11> to 28.59 x 10<11> Kg. mm<2>) where E is Young Modulus and I is the moment of inertia about a transverse axis of the cross-section. |
