A process and device for detecting fouling of an axial compressor by measuring of pressure fluctuations within at least one of the stages of said compressor in the region of the compressor housing by means of at least one pressure sensing device, deriving a frequency signal from the signals delivered...http://www.google.com/patents/US5479818?utm_source=gb-gplus-sharePatent US5479818 - Process for detecting fouling of an axial compressor
