| 摘要 |
An insert is provided for insertion through an opening in the surface of a conduit 20, the insert comprising an insert body 12 having first and second open ends defining an axis of flow therebetween. The insert includes a valve flap 16 connected to the insert body 12. The valve flap 16 is moveable between a closed position in which it creates a closure that prevents flow along the axis, and an open position in which the valve flap 16 allows flow along the axis. The valve flap 16 is arranged so that, when in the open position, it is substantially U-shaped in side cross-section and is oriented with respect to the insert body so that the U-shape arches over the axis of flow. |
