DTH-HAMMER DRILLING DEVICE AND OVERBURDEN DRILLING METHOD

摘要

The invention relates to a DTH-hammer drilling device, comprising a down-the-hole- (DTH-) hammer (6) with a percussion drill bit (9), a drill pipe (2) with a waste conduit for the cuttings and at least one supply conduit for the flushing medium and a flushing medium supply device, wherein a seal (18) for sealing the borehole against the borehole opening is provided in a fixed distance from the drilling head (6), or wherein a casing tube (12) is connected to the drill bit (9). The invention further relates to an overburden drilling method, comprising rotating a drill bit (9), supplying an energy transfer medium through a drill pipe (2) to the rotating drill bit (9) for transmitting a percussive action thereonto, dragging a casing tube (12) along with the drill bit (9) and flushing away cuttings through the drill pipe (2).