Condition monitoring of low-speed rotating machinery using stress waves part 1

摘要

Condition monitoring through the use of vibration analysis is an established and effective technique for detecting the loss of mechanical integrity of a wide range and classification of rotating machinery. Equipment rotating at low rotationalspeeds presents an increased difficulty to the diagnostician [1-4, 23], since conventional vibration measuring equipment is not capable of measuring the fundamental frequency of operation. Also, component distress at low operational speeds does notnecessarily show an obvious change in vibration signature. This paper presents a study of high-frequency stress wave analysis as a means of detecting the early stages of the loss of mechanical integrity in low-speed machinery. Investigations were centred on the rotating biological contactor (RBC) which is usedfor sewage treatment in small communities and rotates between 0.6 and 1 r/min (0.0167 Hz). The mechanism of stress wave generation was the relative movement between mating components experiencing loss of mechanical integrity, e.g. the loss of tighteningtorque between clamped components.