Method and apparatus for symptom diagnosis by monitoring vibration of shaft of rotary machine
First Claim
1. A method of symptom diagnosis by continuously detecting vibration of the shaft of a rotary machine and monitoring a signal indicative of the detected shaft vibration for the diagnosis of the operating condition of the rotary machine, said method comprising:
- establishing a predetermined safety region in which said detected shaft vibration signal is indicative of a relatively low level permitting continuous operation of the rotary machine;
monitoring the behaviour of said detected shaft vibration signal within said safety region; and
determining the presence of a symptom of unusual operation of the rotary machine on the basis of the result of monitoring of the behaviour of said detected shaft vibration signal within said safety region.
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Accused Products
Abstract
A method of symptom diagnosis by continuously detecting vibration of the shaft of a rotary machine and monitoring a signal indicative of detected shaft vibration for the diagnosis of the operating condition of the rotary machine. In the method, a symptom of unusual operation of the rotary machine is diagnosed. The rotation speed range of the rotary machine is classified into a safety region, an alarm region and a trip region depending on the level of the shaft vibration signal. According to the disclosed method, symptom diagnostic regions are established within the safety region at time intervals of a symptom diagnostic period, and whether or not the level of the detected shaft vibration signal deviates from that of the symptom diagnostic regions is continuously monitored for the diagnosis of a symptom of unusual operation of the rotary machine.
62 Citations
21 Claims
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1. A method of symptom diagnosis by continuously detecting vibration of the shaft of a rotary machine and monitoring a signal indicative of the detected shaft vibration for the diagnosis of the operating condition of the rotary machine, said method comprising:
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establishing a predetermined safety region in which said detected shaft vibration signal is indicative of a relatively low level permitting continuous operation of the rotary machine; monitoring the behaviour of said detected shaft vibration signal within said safety region; and determining the presence of a symptom of unusual operation of the rotary machine on the basis of the result of monitoring of the behaviour of said detected shaft vibration signal within said safety region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of diagnosing an unusual symptom of operation of a rotary machine in a region of safe operation wherein a signal indicative of shaft vibration of the rotary machine is monitored and in the region of safe operation an amplitude value of the shaft vibration signal is smaller than a predetermined value, and an amplitude change rate of the shaft vibration signal is smaller than a predetermined value, the method comprising the steps of:
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detecting at least one of the amplitude value of the shaft vibration signal and the amplitude change rate value of the shaft vibration signal, at a predetermined diagnosing period, setting and memorizing at least one of absolute values of a predetermined change from the amplitude value and the amplitude change rate value of said shaft vibration signal respectively, based upon the values therefor detected at the nth diagnosing period, for the purpose of using the absolute values as reference values for determining whether an unusual symptom is present at the (n+1)th diagnosing period, calculating the absolute values of deviations between at least one of the amplitude value and the amplitude change rate value thereof of the shaft vibration signal at the (n+1)th diagnosing period, and at least one of the amplitude value and the amplitude change rate value thereof of the shaft vibration signal at the nth diagnosing period respectively, determining the presence of a symptom of unusual operation of said rotary machine in the safe operation region when at least one of the calculated variations exceeds the set and memorized values of the reference values. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. An apparatus for diagnosing an unusual symptom during safe operation of a rotary machine by detecting and monitoring a shaft vibration signal due to the rotation of said rotary machine, the apparatus comprising:
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timing signal generating means for generating timing signals for delimiting unusual symptom diagnosing periods during the safe operation of said rotary machine; first and second means for detecting and memorizing an amplitude value of said shaft vibration signal in response to timing signals at the nth and (n+1)th unusual symptom diagnosing periods; third and fourth means for detecting and memorizing a value of the change rate of the amplitude of said shaft vibration signal in response to timing signals at the nth and (n+1)th unusual symptom diagnosing periods; determination-reference memory means for setting and memorizing a change of the detected amplitude value and a change of the detected change rate of the amplitude value of said shaft vibration signal in the nth unusual symptom diagnosing period as determination reference values for the unusual symptom diagnosis at the (n+1)th unusual symptom diagnosing period; first calculating means for calculating the difference between the values memorized in said first and second memory means; second calculating means for calculating the difference between the values memorized in said third and fourth memory means; first comparing means for comparing the calculation results fo said first calculation means with the value of the change of the amplitude value memorized in said determination-reference memory means; second comparing means for comparing the calculation results of said second calculation means with the value of the change of the change rate of the amplitude value memorized in said determination-reference memory means; and means for determining the presence of a symptom of unusual operation of the rotary machine when at least one of said first and second comparing means provides an output indicative of the calculation result exceeding the value of the change set in said determination-reference memory means. - View Dependent Claims (20, 21)
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Specification