| 摘要 |
<p>Method and apparatus are provided for refining glassy material or the like by vacuum. The material is first melted and then introduced into a vacuum chamber, preferably into space above liquid held in the chamber. Other aspects involve a two-step melting process preparatory to the vacuum refining, in which the material is initially liquefied in one stage and dissolution of particles is substantially completed in a second stage. The molten material is preferably foamed immediately upon entry into the vacuum chamber.</p> |
