| 摘要 |
<p>Drilling through a wall of a molten material containing vessel, such as a glass melting tank, for the purpose of inserting an electrode or the like, is facilitated by employing a drill rig in which the drill bit is carried on the end of the electrode, which in turn is mounted on reciprocating means. The reciprocating means preferably includes a fast-travel mechanism and a high-powered hydraulic cylinder acting in tandem.</p> |
