| 摘要 |
A ball valve (10) for sealing a conduit (12) is described. The ball valve includes a housing having a throughbore and a valve seat. An apertured ball element (18) is mounted within the housing and is rotatable about an axis of rotation (38) between a throughbore open and a throughbore closed position. The apertured ball element (18) has a first portion (20) and a second portion (22) coupled together which are rotatable and moveable relative to each other. The first portion has a sealing surface for engaging with the valve seat. In use, in the throughbore closed position, the second portion is moveable relative to the first portion to axially displace the first portion from the axis of rotation towards the valve seat such that the sealing surface on the first portion of the apertured ball forms a seal with valve seat.
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