PURPOSE: To provide a cavitation detector of a fluid machine wherein cavitation can be detected by separating a signal caused by the cavitation from impact noise detected with an acoustic sensor.
CONSTITUTION: An acoustic sensor 2, a wave height level detector 4 for comparing its acoustic signal with a wave height threshold value, an excess time comparator 5 for outputting a cavitation state signal when a time which exceeds the wave height threshold value exceeds a set excess time after the signal compares the time which exceeds the wave height threshold value with the set excess time, a minimum excess time producer 6 for outputting a preset excess time signal and a cavitation state output device 7 for performing measurement display and preservation from the cavitation state signal are included.
TSUNEOKA OSAMU
TATEBAYASHI YUICHI
HANAWA JUN
