| 摘要 |
Method for drilling with a core drill with reversed flushing. As the core (25) formed by the drill moves inwardly into the drill tube (5), the inner surface (24) ahead of the core is cleaned from debris (55) by a cleaning device (6), which is moved by and at small distance ahead of the core. Hereby clogging of the suctionspace (23) between the core and the inside of the drill tube is prevented. A core drill comprising a cleaning device (6) inside the drill tube (5), arranged to be moved by the core (25) in cleaning interaction with the inner surface (24) of said drill tube. The device (6) is specially designed as a freely moving insert or piston with a sleeve-formed cleaning element (51) and a cross-element (61) partially obstructing the cross-section of the drill tube (5), said cross-element having a central, substantially reduced, area forming a suctionhole (63). |
