| 摘要 |
For use with a top drive power unit supported for connection with a well string in a well bore to selectively impart longitudinal and/or rotational movement to the well string, a feeder for supplying a pumpable substance such as cement and the like from an external supply source to the interior of the well string in the well bore without first discharging it through the top drive power unit including a tubular member or mandrel extending through an outer housing which is sealably and rotatably supported thereon for relative rotation between the outer housing and the tubular member. The mandrel and outer housing have flow passages for communicating the pumpable substance from an external source to discharge through the outer housing and mandrel into the interior of the well string below the top drive power unit. The mandrel includes an arrangement to releasably position a pump down plug for discharge into the well string and for positioning a barrier to selectively dislodge the barrier into the well string through the mandrel.
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