Ceramics-Silikáty 52 (4) 240-249 (2008)

GLASS MELTING AND ITS INNOVATION POTENTIALS: THE ROLE OF GLASS FLOW IN THE BUBBLE-REMOVAL PROCESS

L. Němec, P. Cincibusová

This work demonstrates how the temperature distribution and glass-melt flow patterns resulting from these temperature gradients in a simple melting space or tank (horizontal orthogonal channel) influence the bubble removal from the melt, depending on changes of the utilisation (by changes in temperature distribution) of the space for the bubble removal process. The results indicate that the effect of the glass-melt flow pattern and the consequent space utilisation on bubble-removal (fining) may be described by two quantities, namely the virtual height of the bubble rising (the height which the bubble has to rise against downward glass-melt flow to the glass level) and the virtual fraction of dead space for the bubble-removal process (the space ineffective for the removal of the critical bubble). The volume performance of the space for bubble removal [m³s^-1] is calculated in this work by using the laboratory values of bubble growth rates (applied to calculate the bubble fining times), the mean residence time of glass in the space and the mentioned two quantities characterizing the space utilisation. The results are intended to support the control regime for optimizing glass-melt flow and developing new concepts of industrial fining spaces designs.

Keywords: Bubble removal, Temperature gradients, Glass-flow patterns, Space utilisation, Horizontal channel