GEAR FOR WITHDRAWAL OF FOREIGN OBJECTS FROM BOREHOLE Russian patent published in 1994 - IPC

FIELD: gas and oil production. SUBSTANCE: gear for withdrawal of foreign objects from borehole has implosion chamber 1 with ducts 2 and inlet chamber 3. The latter houses mobile funnel 6 and tie-rods 7 fixed with lock-pins connected to protrusions 9 of striking mechanism 10 without action on gripper 8. Striking mechanism 10 is located below stepped diaphragm 11. When gear reaches location of foreign objects funnel 6 stops but gear continues to move downwards. In this case relative translation of tie-rods 7 and striking mechanism 10 takes place. As a result protrusions 9 are released and striking mechanism 10 operates. Fluid comes into implosion chamber 1 through hole formed in diaphragm 11 with high speed. Foreign objects are drawn in into chamber 3 together with current of fluid and collect in it above gripper 8. Fluid fills up chamber 1, opens ducts 2 and flows through them into borehole. EFFECT: enhanced reliability of operation of gear. 3 dwg