CONTROL METHOD OF TWEEL IN FLOAT METHOD GLASS PLATE MAKING

摘要

PURPOSE:To prevent the fluctuations in plate width and achieve the improvement of yield by beforehand setting the range of the deviations where the plate width of the glass strip on a molten metal bath deviates from a reference value and controlling of the time when the deviation signal is within the set range and when it exceeds the same. CONSTITUTION:In the float method glass plate making, a deviation range is beforehand set. If the amount of the molten glass flowing on a molten metal bath 3 through a channel 1 past a tweel 4 is large as a result of the detection by video analyzers 8, 8' and a radiation thermometer 6 and the plate width of a glass strip 9 exceeds a reference value, a comparing arithmetic circuit 12 transmits a deviation signal. If this is within the permissible range, a mean value control or integral control circuit 15 operates to output the signal corresponding to the deviation amount. According to this signal, the tweel lowers. If it exeeds the permissible range, a sample PI control circuit 16 operates to output the signal corresponding to the deviation amount and according to this signal, the tweel lowers. This is virtually the same even when the amount of the molten glass is small.