MELTING AND REFINING OF GLASS OR THE LIKE WITH VACUUM REFINING

摘要

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.