DRILL CIRCULATING VALVE Russian patent published in 2011 - IPC E21B21/10 

FIELD: oil and gas production.

SUBSTANCE: circulating valve consists of coaxial case and piston inter-engaged by means of pins and slots. The first system consists of a case, of a closer with channels communicating an internal cavity of the system with annular space of a well, of a packing, of an upper and lower arresters of piston travel; while the piston system consists of the piston with a throughput channel and a packing, of a valve switch with radial channels and of a compression spring. The throughput channel of the piston converges at an inlet section and diverges at an outlet section. At a section of maximal convergence a bypass channel is made in the piston; the channel hydraulically communicates the throughput channel with a behind-the piston cavity.

EFFECT: reliability of valve, reduced output of hydraulic power for drilling and hole conditioning.

4 cl, 9 dwg