GB983556A - Improvements in or relating to processes for the manufacture of sheet or plate glass - Google Patents

Abstract

In the manufacture of sheet or plate glass by flowing the glass on to the surface of a bath of molten metal, the ribbon of glass is locally detached from the surface of the molten metal to expose a portion of the lower face of the <PICT:0983556/C1/1> <PICT:0983556/C1/2> ribbon, a neutral or reducing atmosphere is established in contact with such lower face and the ribbon of glass is then permitted to rest once again upon the bath of molten metal. The ribbon 2 of glass flowing over the surface of a bath 1 of molten metal may as in Fig. 1 be raised at 2A by passing over a roller 3, which is rotated by the ribbon 2 and leaves spaces 5, 51 either side into which a neutral or reducing gas may be delivered. Alternatively, the roller 3 may be porous, as porous graphite, and the gas introduced into the roller to escape through the pores. The ribbon 2 may be removed from the bath 1 by passing up a deflector 4 of graphite. As in Fig. 2, a chamber 14 of refractory material has a porous top plate 7 and gas through pipe 8 to the inner cavity 6 passes through plate 7 to form a layer 9. The gas is evacuated by suction applied to conduits 12, 13 in grooves 10, 11 and to prevent any possibility of the gas continuing with the ribbon 2, the suction is sufficient to remove also a small amount of the molten metal, which may then be returned to the bath. In addition to the gas under the ribbon, an inert or reducing atmosphere may be established above the whole of the hottest portion of the bath from the flowing-on point up to where the ribbon rejoins the molten metal.