FRAGILE INNER CORE-RECEIVER Russian patent published in 2018 - IPC E21B25/00 

FIELD: drilling of soil or rock.

SUBSTANCE: group of inventions refers to the arrangement for drilling with core selection, the core inner tube node and the method of drilling with core selection. Core sampling configuration comprises a core drill bit, an outer core-receiving pipe connected to a core drill bit, an inner core-receiving pipe installed in the outer core-receiving pipe, and an inner sleeve installed in the inner core-receiving tube. Inner sleeve is a single continuous sleeve. Inner sleeve contains a number of brittle zones spaced along it. Strength of the first of the plurality of brittle zones is different from the strength of the second of the plurality of brittle zones.

EFFECT: minimizing the negative consequences of core seizure and ensuring the continuation of core sampling after one or more core seizures.

17 cl, 11 dwg