FI933024A - Downhole - Google Patents

Abstract

The invention relates to a drilling arrangement comprising a drilling device 1 which has at least drilling means 2 and preferably connecting means 3 for fastening a drill rod 4 for increasing the drilling depth of the drilling arrangement. The drilling arrangement 1 functions by means of a feed movement in the direction of its longitudinal axis s and a striking movement 6 to and fro or the like, and a rotary movement w around its longitudinal axis s. The drilling arrangement has at least striking means 8 which are arranged so as to function by means of a liquid-like pressure medium which is conducted from the pressure-medium system of the drilling arrangement through the second flow arrangement 9. The striking means 8 include a hollow body part 7, a valve and control flow arrangement which controls the pressure-medium flow therein, a piston arrangement 10 which, acted on by the striking means, implements said striking movement, and preferably an accumulator arrangement 11 which stores pressure medium. To minimize the cross section of the striking means 8, at least one flow path, such as the inlet flow path 9a and/or the return flow path 9b, of the second flow arrangement 9, which flow path is located essentially in association with the piston arrangement 10, is divided into two or more flow parts. <IMAGE>