Abstract: Pulverizer coal flow pipes feed a mixture of air and coal to burners in electric utility coal fire facilities. A method and apparatus for sensing relative coal flow in the pipes uses acoustic emission (AE) sensors to detect flow in each pipe. Sensed relative flow in the pipes is used to balance flow in the pipes and to further adjust pipe coal flow. Sensed flow is used with control parameters of a furnace to maximize power plant efficiency and to ensure compliance with emissions requirements.

Abstract: The disclosure is directed to a technique for monitoring signals emanating from a ceramic article (10) during a soldering operation. In order to determine whether the signals are stress wave emissions (SWE's) or noise the number of pulses (41) of the monitored signal having an amplitude exceeding a preset threshold (51), during a period of time, are counted. A count (62) proportional to the area under the envelope of the detected signal during the period of time is also made. A ratio of the count related to the area under the envelope to the pulse count is formed and compared to an empirically developed range of ratios which are indicative of a stress wave emission signal.