Equipment for the Production of Glass Half Products

The five stages of the melting process as described in Sects. 3.1 and 3.2 occur in the melting equipment. These processes occur in chronological order in a discontinuously working pot furnace (Fig. 3.5), or parallel in different places in the continuous tank furnaces. Many types of melting furnaces are used. A specific example of a continuously working furnace is shown in Fig. 3.11. 

Both tanks of the cross-fired furnace (Fig. 3.11) are standing on steel supports and the walls are fixed by rods. The flames generated by the burners (3) cross the melt level at a right angle to the melt stream in the melt basin (1) and leave the room above the glass level through the opposite burner port. The 

Because the combustion of natural gas or oil takes place with air, its nitrogen part oxidises to the problematic NOj,. The amount and precise composition of NOj strongly depend on the preheating temperature of the air and the combustion temperature. Beerkens [30] deals with possibilities to reduce the NOa emission. 

The flame arrangement may be cross-fired, as shown in Fig. 3.11, or like an U. In this case two burner ports are positioned at the end face of the tank. The flame comes out of one burner port, heats the melt, returns at the wall 

If the specific electrical resistivity of the glass at elevated temperatures drops below a threshold of about 40 Q cm, the glass becomes a practically 

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Equipment for the Production of Glass Half Products point load... 

Xylene (100 g., 0.94 mole) is placed in a flask equipped with an efficient reflux condenser and strongly illuminated. To the o-xylene is added slowly 624 g. (200 ml., 3.9 moles) of dry bromine. (Hood.) The temperature of the reaction mixture is increased to about 120° by the time half the bromine is added and then raised gradually to 160° and maintained at this temperature for 2 hours. Loss of xylene by entrainment with the hydrogen bromide evolved may be minimized by packing the reflux condenser with glass beads. With good illumination a total reaction time of 3 hours is sufficient. Any excess bromine is distilled off, and the product is allowed to cool. It is washed with a small amount of chloroform and then recrystallized from chloroform. There is obtained 250-260 g. (74-77%) of tetra-bromo compound, m.p. 116°. 

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