Acoustic Resonance-Based Method for Long Distance Liquid Level Detection

Liquid level distance can be determined by the fundamental resonance frequency (RF) or a series of RFs from the acquired acoustic signals using the acoustic resonance-based method (ARM). However, in practical industrial applications, long distance liquid level detection remains a challenge due to a lack of measurement accuracy and reliability. In this study, an improved measurement strategy based on ARM is proposed. A mathematical model of the acquired signal is established, which provides a theoretical foundation for the extraction of resonance characteristics. A parameter estimation algorithm based on the interpolation of discrete Fourier transform (DFT) coefficients is developed to enhance the measurement accuracy. The tests are carried out on different pipelines and a good agreement between the proposed strategy and sound reflection-based method (SRM) is observed, which validates the effectiveness of the proposed method. The experimental results also revealed that the new detection method demonstrates high accuracy and stability for long distance liquid level measurement.