| 主权项 |
1. A well barrier for sealing a downhole conduit, the well barrier comprising:
a housing defining a throughbore having a longitudinal axis; a valve actuator comprising a piston being axially movable; and a flapper valve including a flapper, the flapper valve being attached to the piston by a hinged connection, the flapper valve and the valve actuator being axially movable with respect to the housing in a direction parallel to the longitudinal axis, the flapper being adapted to move from one of a throughbore open and throughbore closed positions to the other of said open and closed positions when the actuator and flapper valve move a predetermined axial distance, wherein the well barrier comprises a first retention device adapted to retain the flapper valve in one of said throughbore open or throughbore closed positions, and wherein the first retention device is fixed relative to the housing. |
