EP0280489A2
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EP
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Cycle monitoring method and apparatus
Assignee: Westinghouse Electric Corp
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Filing: 1988-02-22
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Granted: —
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Expires: 2008-02-22
Abstract
Abstract A monitoring system for testing the life of components by using sensors in a process control plant, monitors the sensors signals and records steady state and transient phenomena to produce time-compressed information. Transient data is retained at a higher sampling rate, so that the parameters of transient such as the maximum value can be determined for stress analysis. The stress analysis determined pressure and thermal stresses which are used to calculate a usage factor which indicates the stress age and thus the remaining life of a component.
Inventors
- 👤 Dali Li
- 👤 Charles Bradley Bond
- 👤 Sam Subbu Palusamy
- 👤 John Cowieson Schmertz
- 👤 John Nicholas Chirigos
- 👤 Chuang Yeh Yang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:21
CPC Classifications
G; G21; G21C; G21C17/00; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
103 words
An on-line monitoring method of assessing cumulative fatigue on a component in use by monitoring cycles using a sensor which produces steady state and transient signals, said method comprising the steps of: (a) sampling a sensor signal from the sensor; characterized by the steps of time compressing sampled steady state signals; (b) producing a compressed transient from the sensor signal when the sensor signal includes a transient; and (c) computing fatigue on the component from the compressed steady state and transient, thereby to indicate ahead of time from an expected fatigue tolerance of the component, as to when the component might need refurbishing.
Claim 2
Dependent Claim
103 words
An on-line monitoring method of assessing cumulative fatigue on a component in use by monitoring cycles using a sensor which produces steady state and transient signals, said method comprising the steps of: (a) sampling a sensor signal from the sensor; characterized by the steps of time compressing sampled steady state signals; (b) producing a compressed transient from the sensor signal when the sensor signal includes a transient; and (c) computing fatigue on the component from the compressed steady state and transient, thereby to indicate ahead of time from an expected fatigue tolerance of the component, as to when the component might need refurbishing.
Claim 3
Dependent Claim
72 words
A method as recited in claim 1, wherein step (a) comprises the steps of: (a1) comparing the sensor signal to a first threshold range; (a2) storing sensor samples at a first sampling rate if the sensor signal is within the threshold range; and (a3) storing sensor signal samples at a second sampling rate higher than the first sampling rate if the sensor signal is equal to or outside the first threshold range.
Claim 4
Dependent Claim
58 words
A method as recited in claim 2, wherein step (a3) includes the steps of: (i) continuing to sample at the second rate until the sensor signal has been within the first threshold range for a predetermined period; and (ii) returning to step (a1) when the sensor signal has been within the first threshold range for the predetermined period.
Claim 5
Dependent Claim
53 words
A method as recited in claim 2, wherein step (b) comprises: (b1) storing the sensor signal samples as transient sensor samples when a current sample is different from a stored sample by a second threshold range; and (b2) determining and storing at least the minimum and maximum sensor signal samples for each transient.
Claim 6
Dependent Claim
62 words
A method as recited in claim 2, wherein step (b) comprises the steps of: (b1) reviewing the stored sensor samples and storing a transient sensor sample when successive sensor signal samples are outside the second threshold range; and (b2) reviewing the stored sensor signal samples and storing the maximum and minimum sensor signal samples when a maximum or minimum are detected, respectively.
Claim 7
Dependent Claim
102 words
A method as recited in claim 5, wherein steps (b1) and (b2) comprise the steps of: (i) storing and designating a sensor signal sample as a base transient sample; (ii) comparing sensor signal samples to the base transient sample, storing and designating the compared sensor signal sample as a new base transient sample when the compared sensor signal sample is different from the base transient sample by the second threshold; and (iii) reviewing sensor signal samples starting with the base transient sample and storing a maximum or minimum when a peak or a valley is detected in the sensor signal samples, respectively.
Claim 8
Dependent Claim
46 words
A method as recited in claim 6, wherein step (iii) is performed for storing the maximum when a sensor signal sample is less than the base transient sample and performed for storing the minimum when a sensor signal sample is greater than the base transient sample.
Claim 9
Dependent Claim
45 words
A method as recited in claim 1, wherein step (c) comprises the steps of: (c1) producing stress from pressure and temperature transient sensor samples; (c2) determining a stress intensity range from the stress; and (c3) producing a component usage factor from the stress intensity range.
Claim 10
Independent Claim
48 words
A method as recited in claim (8), wherein step (c1) comprises the steps of: (i) computing pressure stress from pressure transient sensor samples; (ii) computing general thermal stress; (iii) computing transient thermal stress from temperature transient sensor samples; (iv) obtaining predetermined load stresses; and (v) combining the stresses.
Claim 11
Dependent Claim
23 words
A method as recited in claim 9, wherein step (iii) of claim 9 includes performing Duhamels integral using the temperature transient sensor samples.
Claim 12
Dependent Claim
72 words
An on line monitoring apparatus for assessing cumulative fatigue on a component in use, by monitoring cycles and by using a sensor which produces steady state and transient signals said apparatus comprising: sampling means for sampling a sensor signal; time compression means for compressing the sensor signal samples into compressed steady state and transient samples; and fatigue determination means for determining component fatigue from said time compressed steady state and transient samples.
Claim 13
Dependent Claim
72 words
An on line monitoring apparatus for assessing cumulative fatigue on a component in use, by monitoring cycles and by using a sensor which produces steady state and transient signals said apparatus comprising: sampling means for sampling a sensor signal; time compression means for compressing the sensor signal samples into compressed steady state and transient samples; and fatigue determination means for determining component fatigue from said time compressed steady state and transient samples.
Claim 14
Dependent Claim
40 words
An apparatus as recited in claim 11, wherein said compression means compares sensor signals to a threshold and stores the sensor signal as a transient sample each time the sensor signal is outside the threshold surrounding the previously-stored transient sample.
Claim 15
Dependent Claim
33 words
An apparatus as recited in claim 12, wherein said fatigue determination means combines stresses on the component, determines a stress intensity range and produces a component usage factor from the stress intensity range.
References Cited (Backward Citations)
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