Patent ID: 7578144

Claim:
A method for homogenizing molten glass comprising: operating a stir chamber, the stir chamber including a rotating stirrer, the stir chamber and the stirrer including a refractory metal; rotating the stirrer at a plurality of different speeds N i as the molten glass flows through the stir chamber, where i indicates the number of speeds N; flowing molten glass through the stir chamber at a plurality of different glass temperatures T j , where j indicates the number of temperatures T; determining an actual refractory metal inclusion rate in the molten glass for combinations of N i and T j ; calculating a distribution of shear stress as a function of stir chamber and stirrer surface areas in contact with the molten glass for the combinations of N i and T j ; using the actual refractory metal inclusion rates and the distributions of shear stress to calculate a threshold value of shear stress σ 0 for each T j ; calculating a refractory metal inclusion rate temperature dependence m t ; using the refractory metal inclusion rate temperature dependence and the threshold value of shear stress to calculate a predicted refractory metal inclusion rate for a predetermined temperature and stiffer rotational speed; and varying the glass temperature and/or varying the stirrer rotation speed in response to the predicted refractory metal inclusion rate to minimize refractory metal inclusions in the molten glass.