| 摘要 |
PURPOSE: To effectively and surely obtain foam-free molten glass by introducing a continuous flow of molten glass into a decompression chamber of a prescribed pressure so that the molten glass flow may stay there for a certain time as the molten glass flows almost horizontally, then discharging the deaerated glass from the chamber. CONSTITUTION: In an atmosphere of a pressure of Pmm Hg, a molten glass G is introduced from a rising tube 14 into the decompression deaeration tank 12, allowed to flow almost horizontally and allow the foams in the molten glass to float up and to be broken on the surface and the defoamed glass is discharged from the downcomer 16. At this time, the pressure which the molten glass undergoes is adjusted in the range within 38-P-50 mmHg and the time of the molten glass G staying in the tank is set to 0.12-4.8 hours calculated as (the weight of the molten glass in the tank, W in tons)/(the flow rate of the molten glass, Q in ton/hour). In a preferred embodiment, the depth of the glass G molten in the tank is represented with H in m, the surface area S1 in m2, and the cross section of the downcomer pipe 16 is represented by S2 in m2 satisfy the following formulas individually: 0.010 < H/W < 1.5 m/ton; 0.24 < S1/Q < 12 m2.Hr/ton and 0.008 < S2/Q < 0.96 m2.Hr/ton.
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