Development of Leak Detection System of Heat Exchanger using Acoustic Emission Technique

Acoustic emission(AE) technique has been applied to not only mechanical property testing but also on-line monitoring of the entire strueture or a limit zone only. Although several AE devices have already been developed for on-line monitoring, the price of these systems is very high and it is difficult for the field to apply yet. In this study, we developed a specially designcd PC-based leak detection system using A/D board. In this paper, AE technique has been applied to detect leak for heat exchanger by analyzing the characteristics of signal obtained from leak. It was confirmed that the characteristics of the signal generated by the turbulence of gas in the heat exchanger is narrow band signal having between 130-250kHz. Generally, the amplitude of leak signal is increased as the leak size increasing, but showed no signi ficant change at frequency characteristic. Leak source location can be found by determining for the point of highest signal amplitude by comparing with several fixcd sensors. In this paper, AE results are compared with the PC-based leak detection system using A/D board.