CASING PIPE VALVE Russian patent published in 2007 - IPC E21B34/06 

FIELD: oil production, particularly for casing pipe cementing.

SUBSTANCE: valve comprises limiter with seat and side channels. Bush is arranged in axial channel of the limiter and is supported by shear members so that bush may close side channels thereof. Stop is made at lower bush end and is shaped as outer annular groove. Limiter is fixedly connected with casing pipe from low limiter side. Casing pipe comprises lower coupling located in lower casing pipe part and having cylindrical recess in lower coupling part. The cylindrical recess receives hollow stem, which may side in upward direction. Transversal stop is fastened to upper end of hollow stem. Hollow stem is fixed in low position with respect to lower bush by means of shear pins. Bush is sealed from below and is hermetically inserted in axial channel of limiter from low limiter side. Bush may slide upwards to provide stop cooperation with lower limiter end. As bush moves upwards bush cooperates with transversal stop and breaks shear members. In upper position bush hermetically seals radial limiter channels from inner limiter side.

EFFECT: increased operational reliability and decreased well construction time.

1 dwg