| 摘要 |
A drill bit (20) for connection to a casing string (R), wherein the bit (20) comprises an annular bit face (21) which is built-up by a matrix and which comprises a sintered diamond-metal powder mixture, wherein the bit face (21) includes a plurality of radially orientated liquid delivery slots (16, 23, 26) for cooling and cleansing the bit face (21), wherein at least one of the liquid delivery slots is comprised of an inner slot (23) which extends radially outwards from the inside (24) of the bit face (21), wherein the slot (23) is terminated with an inner bottom (24) in the bit face (21), wherein a further liquid delivery slot comprises an outer slot (26) that extends radially inwards from the outside (27) of the bit face, and wherein said outer slot is terminated with an outer bottom (28) in the bit face (21). |
