Method and arrangement to establish during down-the-hole drilling communication between the cavity of the drill string and the surrounding material

Abstract

The invention concerns a method to establish communication between the inner cavity of a drill string and the surrounding material down in a drill hole () during the use of a down-the-hole drill unit with a drill string (), a down-the-hole hammer drill (), and a source of pressurized medium () that delivers a medium under pressure to the down-the-hole hammer drill. Communication is established through: (a) that a tube section () of the drill string () is assigned openings (), (b) that a piston () with an axial channel () is arranged, (c) that the piston () is inserted into the cavity of the tube section () in a manner that allows sliding, (d) that the piston () allows driving fluid to be led through a channel () from the source of pressure () to the down-the-hole hammer drill (), (e) that the piston () is assigned a first part () of a recovery means (), which part can be united with a second part (), (f) that a lifting arrangement () is arranged at the surface level, (g) that the second connector () of the recovery means () is lowered into the drill hole (), the piston () is fished up out of the drill hole and the compartment in the cavity of the tube section () that is formed is used as a measurement compartment.