Experiment on fault diagnosis of air compressor ring valve leakage using acoustic emission

The faults of self-acting valves in a reciprocating air compressor can be diagnosed using the acoustic emission. Four typical valve faults including the crack, rupture and deformation in the valve discs and the leakage through the flow passage were investigated. The acoustic emission of the failed discharge valves was collected from an air reciprocating compressor. The fault features were extracted by comparing the acoustic emission signals from the failed valves with those from the normal valves. The results show that the characteristic locations of the opening and closing of the discharge valve could easily be determined by the envelope waveform of the acoustic emission signals, and the changes in these locations were identified as the valve faults including the rupture and deformation in the valve discs and leakage. The extent to which the valve failed could be estimated by the deviation of the opening/closing locations from the standard ones, the RMS, and the energy. The rupture and deformation in the valve discs and leakage could also lead to the increase in the amplitude of the acoustic emission wave, the value of RMS, and the energy. However, the crack in valve discs could not be identified by acoustic emission signals effectively.