Application of ultrasonic measuring techniques in industrial glass melting

Abstract

The potential applications of ultrasonic measurements in glass melts have been studied, using a measuring system comprising ultrasonic waveguides of polycrystalline translucent Al2O3. These high-temperature buffer rods serve to transport ultrasonic signals into the glass melt and to receive acoustic echoes generated in the melt, respectively. The fundamental acoustic properties of a soda-lime-silica glass composition as a function of temperature have been obtained experimentally: The observed sound velocity varies from 2.86 km/s at 1150 °C to 2.70 km/s at 1300 °C. The observed attenuation of 1 MHz waves has a minimum at 1300 °C of 840 dB/m. For 100 kHz waves the attenuation is a factor 100 lower. It is concluded that 100 kHz ultrasonic signals can be utilized for detection of bubbles with critical radii (≥ 0.2 mm) in a feeder, for measurement of glass flow velocities and for measurements of glass temperature. For measurement of the residual thickness of refractory bricks of a glass tank, application of echo acoustic sensors an the outer surface of the wall probably is more practical.