| 摘要 |
<p>The invention consists of a cylindrical hollow stuffing box (1) for accommodating geometrical differences between rotating, passing drill pipes (B) and pipe connectors (B' ') the diameter of which exceeds that of the drill pipe. The stuffing box (1) consists of an outer housing (2), an upper ceramic disc (3) with an upper set of sipes (4), a lower ceramic disc (5) with a lower set of sipes (6), an outer packer (7) and an inner packer (8) surrounded by an annulus (9). The inner packer (8) seals against the drill pipe (B) such that the packer (8) during operation rotates together with the passing drill pipe (B). The discs (3,5) are fastened to top and bottom of the housing (2) and have an opening, the diameter of which exceeds the diameter of the pipe connectors (B' '). The packer unit with the integrated sipes (4,6) will also be rotated by the drill string during operation, as the sipes (4,6) abut the discs (3,5). When the pipe connector (B' ') is to pass down through the stuffing box (1), then firstly the upper sipes (4) and then the packer (8) will be forced out into the annulus (9), and as soon as the pipe connector (B' ') has passed the upper sipes (4) these will be forced back by the pressure in the annulus (9) whereafter the lower sipes (6) are correspondingly activated.</p> |
