OVERFLOW VALVE OF DRILL COLUMN Russian patent published in 2018 - IPC E21B21/10 

FIELD: drilling of soil or rock.

SUBSTANCE: invention relates to the field of well drilling and repair, in particular to devices for communicating the internal cavity of a process pipe string with annular space when carrying out tripping operations to fill the column with borehole fluid and emptying, namely to the overflow valves of the drill string. Device includes hollow body 1 consisting of upper 2 and lower 3 half-shell. Hollow piston 4 is installed in the upper half-shell with the possibility of opening drain radial 5 holes and is made differential – at the top of a smaller diameter, at the bottom of a larger diameter. Seals 6 and 7 on cylindrical surfaces 8 and 9 mating with the upper half-body are provided with an interference tightening that ensures the retention of the hollow piston in the upper half-shell. In distributor 10, pressed in the lower half-body, there are radial inlet ports 11 connecting inner cavity 12 of the distributor with space 13, as well as longitudinal bypass channels 14 connecting cavity 15 of the upper half-shell with space 16 under the distributor. Seat 17 to which conical core 18 with seal 19 and spring 20 interacts, is mounted in cap 21 connected to the distributor.

EFFECT: reliability and durability of valve operation in the drill string is increased.

1 cl, 3 dwg