利用声发射的往复空压机环状阀泄漏故障诊断试验

Experiment on Fault Diagnosis of Air Compressor Ring Valve Leakage Using Acoustic Emission

利用声发射信号对往复空压机气阀进行了故障诊断,并以某往复空压机的排气阀为例,结合有效电压和能量对气阀漏气、阀片裂纹、阀片断裂及阀片变形等故障进行了测量,从而获得了故障特征信号.研究结果表明:随转角变化的声发射信号包络波形能体现排气阀启、闭的特征位置,气阀漏气、阀片变形及断裂等会导致气阀启、闭特征位置发生变化;根据启、闭特征位置偏离度及相应的有效电压和能量,可以判断气阀故障的严重程度;声发射包络波形平均幅值及相应的有效电压和能量,可以体现气阀漏气、阀片变形及断裂等故障.通过试验结果还发现,阀片裂纹不能通过声发射信号来识别.

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.