VALVE FOR CASING STRINGS Russian patent published in 1994 - IPC

FIELD: drilling practice. SUBSTANCE: valve has pins rigidly connected with crosspiece ring and disposed in its peripheral axial channels with a possibility of axial movement and being accommodated in axial throttle channels of body, and studs with chamfered ends and serrations. Body and crosspiece ring have, respectively, blind and through holes for the studs. Crosspiece ring is positioned above body and in joined position the chamfered stud ends stand out above crosspiece ring and serrations are positioned either level with or above the crosspiece ring. Return valve is of the plate articulated revolving type, installed under the body. EFFECT: higher reliability and better regulation of string filling with fluid. 2 cl, 8 dwg