Patent ID: 9453403
Filing Date: 2016-09-27
CPC Classification: E21B

Claim Text:
1. A method to allow communication to be established between an inner cavity of a drill string and a surrounding material in situ down in a drill hole during use of a down-the-hole drill unit that includes the drill string formed from a number of drill rods coupled at ends thereof, a down-the-hole hammer drill fixed at one end of the drill string, and a source of pressurised medium that delivers a medium under pressure to the down-the-hole hammer drill and that is connected to another end of the drill string, the method comprising operational steps: (a) that a tube section of the drill string having at an outer cover thereof one or several openings with an area of opening that has been determined in advance is provided, (b) that a piston with an axial penetrating channel is arranged, (c) wherein the piston is arranged so as to glide axially inside the cavity of the tube section, (d) wherein the piston is designed so as to allow driving fluid to be led through the channel from the source of pressure to the down-the-hole hammer drill when the piston is located at a most withdrawn position thereof in the tube section and in contact with the down-the-hole drill unit in a manner that allows fluid to flow, (e) wherein the side of the piston that faces the source of pressure has a first connector of a recovery unit, which first connector can be coupled together in a retaining manner with a second connector that is a component of the recovery unit, (f) that a lifting arrangement is arranged at a surface level in connection with the drill hole, and (g) that the second connector of the recovery unit, fixed at the lifting arrangement that is arranged at the surface level, is caused to enter into retaining interaction with the first connector by being lowered down into the drill hole by the lifting arrangement, after which the piston is fished up out of the drill hole by the lifting arrangement, so that a compartment that is formed in the cavity of the tube section as a result of fishing up of the piston can be used as a measurement compartment.