Method Of Making Float Glass

Where the refining zone of the glass melting furnace has a silica refractory roof, the particles of trdymite formed there are dislodged mechanically about twice a year. This step is carried out when the defect density of the glass attributable to trydymite frost stones is at over 0.3/100 ft2. The mechanical means may be the use of a rod or probe. or of gas blasts at 1800-2400F against the roof.