Dth-Hammer drilling device and overburden drillingmethod

摘要

The device has a down-the-hole hammer with a percussion drill bit. A drill pipe (2) is arranged with a channel for cuttings. A supply channel is provided for a flushing medium and a flushing medium supply device. A seal (18) is arranged for sealing a borehole against a borehole opening. The seal is provided at a fixed distance from a drill head (6). An overlapping pipe is connected to the percussion drill bit. An independent claim is also included for a method for drilling.