FIELD: avoidance of forming deposits and inorganic salts on down-the-hole equipment. SUBSTANCE: ferromagnetic tube is provided with axial ferromagnetic rod forming working passage. Permanent magnets in form of blocks are located on this rod. Magnets secured on rod form ring; like poles of magnets are directed to surface of ferromagnetic rod. Magnets are embraced on the outside by monolithic casing made in form of non-magnetic spindle. Pointed end of this casing is directed towards flow of liquid; magnets are located in portion of casing having maximum diameter. Secured over end faces of magnet block on ferromagnetic rod are cylindrical non- magnetic bushes provided with helical passages. Turbulence of liquid flow in antinode of intensity of magnetic field after flowing through helical passages and after flowing over surface is optimal, thus ensuring high efficiency of magnetic treatment of liquid. EFFECT: enhanced efficiency. 3 cl, 3 dwg
