An ultrasonic level measuring technique based on radiation dissipation and its industrial application

• A non-instructive method using ultrasonic sensors is proposed to meet the challenge of dust in level gauging.
• Vibration damping theory was applied to interpret the ultrasonic energy dissipation.
• Influence of frequency and amplitude of the launching ultrasonic signal on the model has been investigated.
• Results of industrial trial show that this method enjoys a bright future in the measurement of material level.

The difficulties occur when traditional level gauging instruments are applied in filling processes, because dust above the interface of material will affect the accuracy of these gauging instruments. A non-destructive method using ultrasonic sensors was proposed in this work to meet this challenge. Theoretical model of ultrasonic radiation damping was derived on the basis of vibration damping theory, and the model was used to describe the relationship between the dissipation of ultrasonic vibration energy and material level. Moreover, influences of frequency and amplitude of the ultrasonic signal on the model were investigated. The results show that the frequency instead of the amplitude has a big influence on the model. Base on these results, proper amplitude and frequency of the ultrasonic signal is decided for the industrial trial in a pulverized coal silo. The predicted level obtained using the model gives error less than 5%. Conclusions can be drawn that the non-destructive ultrasonic method enjoys a bright future in the measurement of material level.