CASING VALVE Russian patent published in 2001 - IPC

FIELD: mining, particularly, process auxiliaries applicable in casing of oil and gas wells. SUBSTANCE: casing valve has hollow body accommodating valve set with axial channels, shutoff member in form of plate wit conical working surface and elastic ring. Connected with plate is spring-loaded rod. Shutoff member has pressure plate secured to rod. Pressure plate has socket for flexible ring on its upper end face. Socket depth is smaller than height of flexible ring. Made on lower end face of plate are projections facing each other and pinching the flexible ring. EFFECT: higher reliability of valve due to excluded overflow of drilling mud or grouting mortar from annular space in course of cement setting. 2 cl, 2 dwg