Abstract:
Silica is reacted with sodium carbonate to form sodium silicate as a preliminary step in a glass melting process. Preferably, calcium carbonate-containing batch materials are calcined separately and then combined with the sodium silicate as liquefying is initiated. The materials may be substantially free of bubble-producing carbonates as the molten phase begins to form.
Abstract:
Glass or the like is melted by liquefying batch materials in a first stage by means of radiant heating, and further advancing the melting process in a second stage where the melt is heated by induction heating. Another aspect of the invention provides a residence zone at the exit of the induction heating stage to aid elimination of gaseous inclusions.
Abstract:
In a two stage glass batch liquefying process, calcium source material is preheated in a first stage in the absence of the major sodium source material, and the heated calcium source material and the sodium source material are combined and liquefied in a second stage.
Abstract:
Liquefying of pulverulent batch materials (e.g., glass batch) is carried out in two stages. The first stage utilizes extended gas/solid contact to heat the materials to an intermediate temperature, and may recover waste heat. The second stage rapidly liquefies the material in a cavity lined with the batch material, and may employ substantially nitrogen-free heat sources. Another aspect involves maintaining a wet condition in the first stage to entrap particulates.
Abstract:
A method for producing decorated glass-ceramic articles is disclosed. The method involves contacting a surface of a crystallizable glass with molten tin and thereafter applying to the tin-contacting surface a stain decorating composition. The article is then fired at a temperature such that the glass simultaneously crystallizes and the stain diffuses into the article to form the decoration.
Abstract:
In a rotating vessel for liquefying pulverulent material wherein the pulverulent material forms a lining on sidewall portions of the vessel, pressing means are provided for creating a flattened end portion at the top of the lining onto which additional pulverulent material is fed and subsequently pressed into the lining. The pressing means is preferably a rotationally driven wheel and the pulverulent material may be glass batch. A more stable feeding operation and reduction of dusting are attained.
Abstract:
Thermally fusible material such as glass batch is liquefied using a solid carbonaceous fuel such as coal as the major energy source. In another embodiment, solid or liquid fuel is mixed with the batch material being fed to an initial liquefaction stage. Melting may be advanced further in a subsequent stage where the melt may also be re-oxidized.
Abstract:
In a glass batch liquefying process, batch-entrained nitrogen is purged by contacting the batch with a substantially nitrogen-free gas in a pretreating stage.
Abstract:
Removal of gas inclusions from a molten glass pool is enhanced by inserting a gas inclusion-permeable, refractory metallic or ceramic screen in the downstream flowing, upper portion of the pool, to diminish the glass flow rate adjacent the surface by viscous drag forces while permitting gas inclusions to rise through the screen to the surface of the molten glass pool to dissipate into the atmosphere therealong.
Abstract:
A novel tank-type furnace is disclosed for producing flat glass from a glass which has a high melting temperature and which contains highly volatile ingredients. The furnace has a tapered end wall construction leading from the melter into the canal. Such a construction results in the formation of better quality flat glass.