CIRCULATION VALVE FOR FORMATION TESTING Russian patent published in 2003 - IPC

FIELD: oil and gas industry. SUBSTANCE: invention refers to circulation valves used to test wells and designed to create circulation " well-pipe " during lift of string. Given valve has body with radial circulation holes housing differential hollow rod with seals mounted for motion, member fixing untimely travel of differential rod carrying collet coupled to differential hollow rod. Fixing member includes cylinder with internal constriction made fast in body, collet is coupled to differential hollow rod with the help of threaded connection. Adjustment nuts altering rigidity of collet are put on both sides of collet. Collet protrusions made in center part of its springy member has chamfers on both sides which rest against internal constriction of cylinder. EFFECT: raised functional reliability of circulation valve. 2 dwg