ACOUSTIC SENSOR UNIT COMPRISING A PARABOLOIDAL COLLECTOR, AND A MACHINE CONDITION MONITORING UNIT ADAPTED TO BE COUPLED TO SUCH ACOUSTIC SENSOR UNIT

摘要

Industrial environments are traditionally noisy, this makes it difficult to do condition monitoring of bearings in such environments. One method according to the invention uses acoustic signals to determine bearing condition. To reduce the noise from frequencies that are not of interest to analyze for determining machine and/or bearing condition, these unwanted frequencies are filtered away as early as possible, even before conversion between acoustic pressure waves to electronic signals. This is accomplished by a parabolic dome having a high pass frequency filter characteristic, thus dampening frequencies below a cut off frequency and amplifying frequencies above. In addition due to the filtering characteristics of the parabolic dome, the electrical signal can advantageously just be enveloped for some further processing.