the six-port regenerative furnace. The melting furnace
holds about 1000 tons of glass and melts the batch at the
rate of 300-400 tons daily using natural gas at approximately
29000F. The molten glass is allowed to settle down
to about 2000'F in the other half of the furnace, called the
refiner. Then the glass is delivered into the tin bath at a
controlled rate. The tin bath is a refractory-lined container
which holds the molten tin on which the glass floats. It is
protected against oxidation by inert atmosphere. The
ribbon formation is controlled by electric heat. Then the
flat glass of ribbon is delivered to the annealing lehr at
about 11000F, where it is gradually cooled to set proper
stress. It is then cut into rectangular pieces and stocked
for further processing (Fig. 1).