| 摘要 |
There is disclosed an annular blowout preventer wherein a packer, received within a recess about a bore through the preventer housing, is adapted to be contracted by means of a piston having an annulus of resilient material movable inwardly within a chamber surrounding the recess and divided therefrom by a wall of the housing, and a disc-shaped member of resilient material extending through and sealably slidable within a slot in the wall to transmit the inward movement of the piston to the packer.
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