The effect of heating and cooling temperatures on rapid cooling time and particle number in auto glass tempering process

Abstract

In terms of tempering quality, controlling and applying of heating and rapid cooling processes are very important in the glass tempering process. In this study, auto glass tempering process was implemented in the prototype glass tempering unit which was designed specifically, exchange of cooling time and particle number was investigated according to heating and cooling temperatures. Without going out of standards, it was aimed to determine the tempering conditions which are needed to keep the energy consumption at minimum in glass tempering process. Glasses that were heated to three different average surface temperatures (Th=620, 650 and 680°C) were rapidly cooled to four different average surface temperatures (Tc=70, 250, 300 and 400°C). The distance between the nozzle and the glass surface is H, the distance between the nozzle axes is S. It was considered 2<H/D<8, S/D=4 and Reynolds number Re=20000. According to the study; while higher heating temperature of the glass resulted in higher particle number, higher cooling temperature resulted in lower particle number. Although there are quite high differences between the sudden cooling times for cooling temperatures Tc=70, 250 and 300°C, particle numbers are close to each other.