| 摘要 |
<p>A stopper rod comprises an elongate body having a first end and a second end. A continuous axial bore extends through the body from an inlet in the first end to an outlet in the second end. A restrictor having an inlet, an outlet and a passageway therebetween, is positioned in the axial bore such that the inlet of the restrictor is closer to the first end than the second end. A gas supply conduit is arranged to supply gas into the axial bore above the inlet of the restrictor.</p> |
