Abstract: A system is provided for locating and identifying an acoustic event. An acoustic sensor having a pair of concentric opposing microphones at a fixed distance on a microphone axis is used to measure an acoustic intensity, from which a vector incorporating the acoustic event is identified. A second acoustic sensor or movement of the first acoustic sensor is used to provide a second vector incorporating the acoustic event. Combination of the first and the second vector locates the acoustic event in space. A command unit in communication with the acoustic sensors can be used for combining the vectors as well as comparing a signal spectra of the acoustic event to stored identified spectra to provide an identification of acoustic event.

Abstract: In order to obtain efficient gas dispersion (aeration where air is the gas) in mixing systems where the circulating impeller is offset from the center of the tank containing the medium in which the gas is dispersed or sparged while being circulated, flooding of the impeller due to entrainment of gas released by the sparging device (a pipe or ring having as outlets) because of the asymmetrical return flow of the medium circulating in the tank which entrains the gas and brings the gas into the area swept by the impeller as it rotates, is avoided by arranging the sparging device to prohibit the release of gas into a region, including a sector of the swept area, where the return flow responsible for flooding occurs. This sector has been found to lie along a line between the center of the tank and the axis of rotation of the impeller. The gas dispersion mixing system is especially useful in dispersion of gas into large volumes (e.g. 20,000 cubic feet).