VALVE UNIT OF DRILLING COLUMN Russian patent published in 2017 - IPC E21B21/10 E21B34/14 

FIELD: drilling of soil or rock.

SUBSTANCE: invention relates to drilling equipment and is intended for hydraulic linking of inner cavity of drill column with annular space during tripping operations and for separation of said spaces in drilling conditions, including at low consumption of drilling fluid (liquid). Valve device of drill column contains elements of drill column and overflow valve, which includes a housing, valve pair consisting of a seat installed in housing, hollow piston arranged inside seat, in which there are radial holes, spring, seal. In overflow valve or elements of drill column, connected with overflow valve, there is a module to interact with hollow piston and reduce or completely cover flow passage of hollow piston at supply of drilling fluid, when inner cavity of drill column communicates with annular space. Furthermore, module can be made with variable cross-section along axis or movable, floating in drilling fluid, or in piston of overflow valve.

EFFECT: technical result consists in improvement of reliability and durability of valve unit, including at low consumption of drilling mud.

5 cl, 7 dwg