Research on non-intrusive acoustic monitoring for valve internal leakage

A non-intrusive acoustic monitoring method for valve internal leakage with dual-sensor is proposed. Sensing device is designed to be able to adjust and lock the contact degree between the sensor and pipe wall, and can be loaded and unloaded quickly. The time-frequency domain features of the acoustic signal, which sampled under the conditions of valve normal, valve leak, pipe tapping, pump starting when the valve at open or closed state, are analysed and compared. Feature extraction approach based on the wavelet packet energy ratio for valve leak acoustic signal is proposed, which can effectively distinguish valve internal leakage and external interferences. It has a high leakage detection sensitivity, and can greatly reduce the sampling frequency and the difficulty of valve internal leakage diagnosis.