| Abstract: | The unusually rapid failure of thermocouple protection tubes when used in glass furnace atmospheres has been found to be due to reaction of the volatilized alkalis in the atmosphere with the aluminum silicates of the tube. Failure of the tubes is due either to differential thermal contraction between the outer reaction layer and the inner unaltered layer of the tube on cooling or to actual corrosion and dripping away of the tube. It is suggested that the use of a much higher percentage of alumina and lower percentage of silica in the tubes may prevent failures from this cause. |
