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(11) | EP 0 985 798 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Apparatus for opening and closing a flapper valve |
(57) A typical flapper valve (10) includes a substantially tubular housing (26), a valve
seat (18) defining a flow passage (18c) therethrough, and a flapper valve closure
member (32) pivotally connected to the housing (26) adjacent the valve seat (18) for
selectively moving between an open position and a closed position against the valve
seat (18). The flapper valve includes a lever arm (36) on the closure member (32).
The lever arm (36) extends from adjacent to the flapper valve pivotal connection away
from the closure member (32). A piston (60) is mounted adjacent to a tubular wall
of the housing (26), and a pivotal connection is provided for operatively connecting
the piston (40) to the lever arm (36). Thus, moving the piston (60) in a first direction
urges the closure member (32) to pivot about the pivotal connection toward the closed
position. Moving the piston (60) in a second direction that is opposed to the first
direction urges the closure member (32) to pivot about the pivotal connection toward
the open position. A control line and fluid communication passages (68a,68b,68c) in
the housing (26) are provided for selectively transmitting fluid pressure from a remote
location to the piston (60) for moving the piston (60) in at least one direction,
thereby urging the closure member (32) to pivot in at least one direction about the
pivotal connection between the open position and the closed position |