| 摘要 |
A drill string element for use in the drilling of a borehole, the drill string element comprising: a main body; and a flow control mechanism, wherein the drill string element defines a first aperture, another aperture and a passage configured to provide a fluid flow path between the first aperture and the other aperture, the first and other apertures provide fluid communication between a volume around the drill string element and the passage, and the flow control mechanism is configured to inhibit the flow of fluid through the passage in a first operating mode and to permit the flow of fluid through the passage in a second operating mode. |
