دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: on a top-drive unit, the device that attaches the unit to the guide rails. See guide rails, top drive.

n pl: on some top drives, the steel tracks on which the top-drive unit travels up and down when the driller raises or lowers the traveling block. The rails also keep the unit from turning when its motor rotates the drill stem. Compare torque track, torque tube. See also top drive.

n: on a portable top-drive unit, the steel rail that is mounted in the derrick and to which the top drive is attached. The top drive moves up or down on the track and, because it is firmly joined to the track, cannot turn as its drive shaft rotates the drill stem. Compare guide rails, torque tube. See also top drive.

n: a large cylindrical tube mounted in the derrick to which a top drive is attached and on which it can move up and down. Like guide rails, a torque tube prevents the top drive from turning when it is connected to the drill stem and is rotating it. Compare guide rails. See also top drive.