REVERSE CIRCULATION HAMMER SPLINE ARRANGEMENT IMPROVEMENTS

摘要

A down-the-hole hammer drill that delivers fluid to a cutting face has particular application, but not limited, to a reverse-circulation (RC) down-hole face sampling hammer drill is tailored to the design of the cutting face to improve flushing of the cutting face. An associated drill bit and drive sub are also disclosed.

主权项

1. A down-the-hole hammer comprising:
a drill bit, the drill bit including a shank and a head having a cutting face; and a drive sub, the drive sub surrounding at least a portion of the shank and cooperating with the drill bit to form fluid passages extending lengthwise along the shank to direct fluid to the cutting face to flush the cutting face, wherein each of the passages initially direct fluid to a different portion of the cutting face, and at least one of the passages delivering a greater flow rate of fluid than the others, thereby directing more fluid to at least one portion of the cutting face in preference to other portions thereof.