DOWNHOLE DAMPER Russian patent published in 2000 - IPC

FIELD: mining industry, particularly, devices for damping of drilling tool chattering. SUBSTANCE: downhole damper includes body with working chamber and sealing unit and splined shaft accommodated in body. Downhole damper is distinguished by the fact that splined shaft has screw thread with special profile, and internal surface of body has screw groove of respective shape with clearance for axial motion of splined shaft thread in it and separated from compensation chamber located between sealing unit and working chamber. Both chambers are filled with gas-liquid filler. The latter compound includes surfactant and air being under pressure corresponding to relationship P > P₁ > P₂, where P is annular space pressure; P₁ is pressure in compensation chamber; P₂ is working chamber pressure. Downhole damper breaks dynamic coupling of drill string with rock cutting tool to optimize operating conditions of rock cutting tool, particularly, roller bits and diamond crown bits and to ensure their serviceability. EFFECT: higher efficiency. 2 cl, 3 dwg