Cavitation detection
First Claim
1. A system for detecting an occurrence of cavitation during operation of a fluid mechanism, comprising:
- an acoustic sensor;
a bandpass filter for filtering a signal from the acoustic sensor, the signal comprising a plurality of frequencies and the filter cutting off all of the frequencies that are less than 1 MHz and passing all of the frequencies up to 5 MHz;
a first detector for providing a signal indicative of an energy in the bandpass filtered signal from the acoustic sensor;
a lowpass filter for filtering the signal from the acoustic sensor;
a second detector for providing a signal indicative of the energy in the lowpass filtered signal from the acoustic sensor;
a reference receiver for receiving a reference value signal, wherein the reference receiver is arranged to receive the signal from the second detector as the reference value signal; and
a comparator for comparing the signal from the first detector with the reference value signal and providing an indication if the signal from the first detector exceeds the reference value signal.
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Accused Products
Abstract
There is disclosed an apparatus and method for detecting cavitation in fluid machines, for example pumps (100). In one embodiment a piezoelectric gasket (102) is used as a sensor to sense cavitation. In some embodiments highpass filters (302), (501) are used to detect ultrasonic acoustic signals in about the MHz range. If the energy in the MHz range is excessive then cavitation is deemed to be occurring and the speed of a motor (110) may be reduced in proportion to the degree of cavitation deemed to be occurring. In another embodiment (FIG. 5) the energy in the MHz range is normalized against the energy in the kHz range. Other sensors (600, 701) are also disclosed.
16 Citations
16 Claims
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1. A system for detecting an occurrence of cavitation during operation of a fluid mechanism, comprising:
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an acoustic sensor; a bandpass filter for filtering a signal from the acoustic sensor, the signal comprising a plurality of frequencies and the filter cutting off all of the frequencies that are less than 1 MHz and passing all of the frequencies up to 5 MHz; a first detector for providing a signal indicative of an energy in the bandpass filtered signal from the acoustic sensor; a lowpass filter for filtering the signal from the acoustic sensor; a second detector for providing a signal indicative of the energy in the lowpass filtered signal from the acoustic sensor; a reference receiver for receiving a reference value signal, wherein the reference receiver is arranged to receive the signal from the second detector as the reference value signal; and a comparator for comparing the signal from the first detector with the reference value signal and providing an indication if the signal from the first detector exceeds the reference value signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification