SETT OCH APPARAT ATT REGLERA TEMPERATUREN OVER EN STROMMANDE KROPP AV GLAS

摘要

Method and apparatus for controlling the thickness of vertically drawn sheet glass. A scanning pyrometer periodically observes the temperature of the glass in a series of zones across the drawing area at the meniscus through which the sheet is drawn. A muffle having a plurality of corresponding temperature control zones extends transversely above the stream of molten glass flowing into the drawing area. The temperature of the glass flowing beneath each zone of the muffle is individually regulated in response to the observed temperature in a corresponding zone at the meniscus to thereby deliver to the drawing area glass at a predetermined temperature which will produce a sheet of the desired uniform thickness.