DEVICE FOR SEALING WELL MOUTH Russian patent published in 2004 - IPC

FIELD: oil and gas extraction industry. SUBSTANCE: device has body with a branch pipe and a compacting element with an axial channel. Upper portion of axial channel of compacting element is formed as truncated cone, lower portion has compacting narrowing part which changes into widening part with reverse obliquity. Outer side of compacting element widens by cone-shaped portions from lower freely hanging member to upper portion, which is embedded into metallic ring-shaped flange by means of metallic skirt with windows. Compacting element is made multilayer and includes at least inner and outer elastic courses and elastic offset link mounted between them. Axial channel of inner course has form of irregular one-pole hyperboloid with compacting narrowing portion displaced lower. Outer surface of inner course and inner surface of outer course are made in such a way that elastic offset link in cross-section is made in form of segment-shaped figure. Sharp edge of segment-shaped figure is cut at upward portion. Ring-shaped plane which forms during cut is adjacent to metallic ring-shaped flange. Lower freely hanging parts of courses have stripping made of harder elastic material. Convexity of segment-shaped figure is directed away from the channel. Inner and outer courses are connected to metallic ring-shaped flange. EFFECT: lower power costs and higher durability due to lowered contact pressures and friction forces. 11 cl, 8 dwg