Читать книгу Encyclopedia of Glass Science, Technology, History, and Culture - Группа авторов - Страница 95

The most recent updraw process has been developed by Asahi Glass Company around 1970 to overcome in a new way the disadvantages of the Fourcault process [5, 6, 8]. With it, a pair of hourglass‐shaped rolls, called “Asahi blocks,” is immersed into the molten glass instead of a débiteuse (Figure 5). The trick then is to make the Asahi blocks rotatable to renew the parting line where the glass leaves from the refractory and devitrification takes place. As a result, much longer drawing periods of up to 2–4 months can be achieved. An additional advantage is that thinner sheets down to 1.1–0.7 mm can be produced, especially for electronics applications, with a width of 1.5–2 m, thanks to the forming stability derived from the Asahi blocks.