PROJECTILE FOR THE WELLS BALL-JET DRILLING

摘要

FIELD: drilling of soil or rock.;SUBSTANCE: invention relates to the wells ball-jet drilling and can be used for the wells drilling in hard rocks. Ball-jet drilling rig contains cylindrical hollow housing by the upper part connected to the drilling pipes string. Inside the housing a hollow piston is located. Between the housing and the piston a spring is installed. Below the piston working part the restraining device hollow cylindrical housing is arranged, in its middle part made with n vertical uniform slots, in each of which axis is fixed, on which the tab is fitted through the hole in its upper part. In the restraining device housing, the nozzle is stationary fixed, under which the inlet windows for balls are made. Restraining device housing lower part is connected to the mixing chamber terminating by the diffuser. Throughout the its stroke length the piston is made with n through slots in its lower working part, at that, the formed by the slots protrusions are formed with flats on the piston outer side so, that they are located above the restraining device housing slots. Each tab upper part is rounded and made with the recess, and the lower part is cut-off at an angle of 45° relative to the projectile longitudinal axis. At one end the flat spring is fixed to the restraining device housing, by the other end resting against the tab recess. Number of tabs is determined from the expression: ; ;where D is the well diameter; d_out is the projectile shell outer diameter; s is the one tab width; d_b is the ball diameter; k is the permissible wear coefficient d_b.;EFFECT: enabling elimination of the tabs breakdown in the interaction with the piston, tabs in the working position reliable retention.;1 cl, 1 dwg