The effect of different cooling unit configurations and cooling temperatures on glass tempering quality

Abstract

In this study, an auto glass tempering process was conducted in different cooling unit configurations and cooling temperatures, and the changes in the sudden cooling time and the number of broken glass particles of the tempered glass plates were examined. Six-millimeter-thick glass plates were heated up to Th = 680°C and then suddenly cooled at four different cooling temperatures (Tc = 70, 250, 300, and 400°C). In the sudden cooling process, the rate of the distance between nozzle axes to nozzle diameter (S/D) was taken as 4 · S/D · 8, the rate of the distance to the glass surface to nozzle diameter (H/D) was taken as 2 · H/D · 8, and the Reynolds number was kept constant at Re = 20,000. According to the results revealed in the study, as the S/D and H/D rates increased, the cooling time increased and the number of particles decreased. It was found that the sudden cooling time and the number of particles changed in inverse proportion to the cooling temperature. When the cooling temperature was decreased from 250°C to 70°C for each cooling unit configuration (S/D = 4, 6, and 8), there was a high increase in the cooling time, whereas the increase in the number of particles was quite small. © 2016 by Begell House, Inc.