Method of diagnosing vibration of rotary machine
First Claim
1. A method of diagnosing vibration of a rotary machine for determining unusual vibration thereof, comprising the steps of:
- detecting vibration of a rotary shaft of the rotary machine and producing a shaft vibration signal representative thereof;
analyzing said shaft vibration signal and producing a frequency spectrum signal indicative of the level of at least one of predetermined frequency components of said shaft vibration;
providing a spectrum setting signal representing a predetermined level of said frequency component;
comparing said frequency spectrum signal with said spectrum setting signal and producing an unusual spectrum signal indicative of whether said frequency spectrum signal exceeds said spectrum setting signal;
converting said shaft vibration signal into an occurrence-frequency distribution signal representative of a distribution pattern of values measured in a predetermined time interval by time-related analysis of at least one component of the shaft vibration signal;
providing an occurrence-frequency distribution pattern setting signal;
comparing said occurrence-frequency distribution signal with at least one of individual predetermined distribution patterns represented by said occurrence-frequency distribution pattern setting signal and producing an unusual occurrence-frequency distribution pattern signal indicative of when said occurrence-frequency distribution signal substantially corresponds with a specific one of said individual distribution patterns represented by the occurrence-frequency distribution pattern setting signal;
providing a source pattern signal; and
comparing respective portions of at least one of predetermined source patterns represented by said source pattern signal respectively with the unusual spectrum signal and the unusual occurrence-frequency distribution pattern signal for producing a source pattern identification signal representative of a source of unusual vibration of the rotary machine.
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Accused Products
Abstract
In a rotary machine mounted on a rotary shaft journaled in journal bearings, a source of unusual vibration of the rotary machine is identified on the basis of the results of the steps of (1) subjecting a shaft vibration signal to frequency analysis for analyzing its frequency distribution, and (2) analyzing the amplitude of the shaft vibration signal and the variation rate of a phase signal of a component related to the shaft rotation frequency among the frequency components of the shaft vibration signal. The present invention is usefully applicable to diagnosis of vibration of a rotary shaft of a large-size turbine or a generator in a power plant by continuously monitoring the shaft vibration for immediately automatically detecting unusual vibration of the rotary machine in the event of occurrence of such unusual vibration. The usefulness is more enhanced when the signal indicative of vibration of the rotary shaft is converted into a digital signal to be analyzed by a digital computer which identifies the source of unusual vibration.
82 Citations
10 Claims
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1. A method of diagnosing vibration of a rotary machine for determining unusual vibration thereof, comprising the steps of:
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detecting vibration of a rotary shaft of the rotary machine and producing a shaft vibration signal representative thereof; analyzing said shaft vibration signal and producing a frequency spectrum signal indicative of the level of at least one of predetermined frequency components of said shaft vibration; providing a spectrum setting signal representing a predetermined level of said frequency component; comparing said frequency spectrum signal with said spectrum setting signal and producing an unusual spectrum signal indicative of whether said frequency spectrum signal exceeds said spectrum setting signal; converting said shaft vibration signal into an occurrence-frequency distribution signal representative of a distribution pattern of values measured in a predetermined time interval by time-related analysis of at least one component of the shaft vibration signal; providing an occurrence-frequency distribution pattern setting signal; comparing said occurrence-frequency distribution signal with at least one of individual predetermined distribution patterns represented by said occurrence-frequency distribution pattern setting signal and producing an unusual occurrence-frequency distribution pattern signal indicative of when said occurrence-frequency distribution signal substantially corresponds with a specific one of said individual distribution patterns represented by the occurrence-frequency distribution pattern setting signal; providing a source pattern signal; and comparing respective portions of at least one of predetermined source patterns represented by said source pattern signal respectively with the unusual spectrum signal and the unusual occurrence-frequency distribution pattern signal for producing a source pattern identification signal representative of a source of unusual vibration of the rotary machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification