Have you noticed we do not call our system a “Leak Detection System” rather an Acoustic Monitoring System? Yes, of course it detects tube leaks but there are many other abnormalities the AMS can detect. Figure 1 depicts a 60 day trend in which both pluggage and a reheat leak are shown.
Ash pluggage between components can resemble a tube leak on the trend pages. However, the spectrum typically manifests as narrowband spikes as opposed to the leak-associated bell curve. See Figure 2. In addition to the difference in spectra, a leak typically gets louder, resulting in an increased trend as seen in Figure 1. As shown in the figure, the decibel levels associated with pluggage do not typically continue increasing as the levels do with a leak. Also note how the reheat leak noise cycles with load whereas the pluggage noise remains fairly steady.
Take advantage of your AMS and utilize it for all it’s worth! Remember, the system can detect tube leaks, feedwater leaks, pluggage, slag, external leaks, stuck sootblowers, leaky poppet valves and more.