Process for producing float glass

摘要

In a process for the production of float glass a gas is discharged against the annealing lehr conveying rolls for a sufficient length of time to condition the rolls so as to prevent them from becoming encrusted and thus damaging the glass ribbon. A glass ribbon 14 (Fig. 1, not shown) is lifted off the float bath 12 on to a pair of rollers 16, 18 in a chamber 48 and is then transferred on to the main lehr rolls 22-28. Spring-loaded carbon pads 44, 46 hone the surfaces of rolls 16 and 18. Drapes 32-42 suspending from the lehr roof substantially eliminate any ingress of air into the lehr but some carryover from the float bath exists which is rich in tin and attacks the stainless steel rolls 22-28. To prevent this a gas, e.g. steam, is periodically directed against the first thirteen rolls and gives them an oxidized appearance. The steam is passed through a V-shaped nozzle 50 (Fig. 2, not shown) having holes in each of its two legs at approximately 45 degrees to the horizontal. The gas pressure is preferably above 25 p.s.i. and at a temperature of more than 200 DEG F., e.g. steam at 365 DEG F. and 125 p.s.i. The gas must contain oxygen and moisture.