Compressors are backbone components of many industrial branches. Failures of compressors can be very costly. Operational and maintenance cost could be saved with proper monitoring technologies. Acoustical methods play a key role for monitoring and trend analyses. In addition to acoustics and vibration measurements at lower frequencies, the sensor and signal processing methodologies have been extended towards higher frequencies. This results in advantages for the earlier prediction of operational states and lifetime of compressor components due to its sensitivity to small scale vibrations and turbulences caused by vibration effects. An increase of friction and micro-shocks, often an indicator for inappropriate operation, does not provide intense vibration. The methodology will be explained by means of a case study of screw type compressors. The combined use of vibration and ultrasound together with advanced data technology has been demonstrated for different operational states and classes of faults. It could be concluded that the combination of vibration and ultrasound provides a promising tool for condition monitoring and fault diagnosis of compressors. Data processing based on machine learning techniques such as deep neural networks enables improved trend analyses.
