HYDROACOUSTIC REFLECTOR Russian patent published in 2000 - IPC

FIELD: mining industry. SUBSTANCE: invention is used in drilling of holes for reflection and return of hydroacoustic pulses generated in process of operation of rock-breaking tool over hydraulic channel of drill pipe string. Reflector has body with upper and lower shifters, bushing arranged coaxially and ring piston placed between body and bushing manufactured from visco- elastic material, for instance, double copolymer CCAHMA. Ring piston together with upper shifter, body and bushing form two chambers, upper one being filled with compressed gas, for example, nitrogen and the other one being filled with washing fluid coming through radial holes in lower part of bushing. Holes have diameter of bushing chosen from condition of impassibility of visco-elastic material through them. In process of operation rock-breaking tool generates hydroacoustic pulses which propagate over hydraulic channel inside drill pipe string from face to floating piston and are reflected back towards face where they are used to adjust axial load on rock- breaking tool. Usage of visco-elastic material in the capacity of material of ring piston makes it feasible to raise operational reliability of reflector thanks both to prevention of gas leaks and to increase of useful volume of gas chamber. EFFECT: improved operational reliability. 2 cl, 1 dwg