| 摘要 |
In the feeding of glass through a forehearth to a bowl with an orifice from which glass is withdrawn, the glass in a region immediately upstream of the bowl is subjected to above-surface heat and to sub-surface Joule effect heat, the ratio being adjusted so that the temperature of the glass issuing from the orifice is substantially uniform. The upper heating may be electric or from gas burners. The temperature maintained in the region is substantially the same as at the orifice. The heating may be controlled from thermocouples in the region or from the perimeter of the gob surface measured with an optical pyrometer. |
