EP0366286A2
Expired / Lapsed
EP
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A method and apparatus for processing electrical signals
Assignee: Rolls Royce DSV Ltd
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Filing: 1989-10-04
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Granted: —
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Expires: 2009-10-04
Abstract
Abstract An apparatus (10) for processing acoustic emissions or stress waves in order to recognise features indicative of variations in the process producing the acoustic emissions comprises a transducer (12) acoustically coupled to a machine or industrial process and arranged to detect the acoustic emissions and produce an electrical signal. The electrical signal is amplified by an amplifier (14) and the mean level of the electrical signal is measured by a mean level detector (18) and the minimum level of the electrical signal is measured by a minimum level detector (20). A ratio measurer (22) measures the ratio of the mean level of the electrical signal to the minimum level of the electrical signal. This method is self compensating for variations in the operating conditions of the machine or industrial process, is not significantly affected by electromagnetic switching transients, and can cope with very high numbers of transient excursions.
Inventors
- 👤 Trevor James Holroyd
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:47
CPC Classifications
G; G01; G01H; G01H1/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
81 words
A method of processing electrical signals in order to recognise signal features indicative of variations in a process producing the electrical signals, comprises the steps of measuring the minimum value of the electrical signal, measuring the mean value of the electrical signal, determining the ratio of the mean value of the electrical signal to the minimum value of the electrical signal, monitoring said ratio for variations of the ratio which are indicative of variations in the process producing the electrical signal.
Claim 2
Independent Claim
81 words
A method of processing electrical signals in order to recognise signal features indicative of variations in a process producing the electrical signals, comprises the steps of measuring the minimum value of the electrical signal, measuring the mean value of the electrical signal, determining the ratio of the mean value of the electrical signal to the minimum value of the electrical signal, monitoring said ratio for variations of the ratio which are indicative of variations in the process producing the electrical signal.
Claim 3
Dependent Claim
26 words
A method of processing electrical signals as claimed in claim 1 in which the electrical signals corresponds to the acoustic emission activity generated by a process.
Claim 4
Dependent Claim
25 words
A method of processing electrical signals as claimed in claim 2 in which the electrical signal corresponds to the intensity of the acoustic emission activity.
Claim 5
Dependent Claim
25 words
A method of processing electrical signals as claimed in claim 2 in which the electrical signal corresponds to the level of the acoustic emission activity.
Claim 6
Dependent Claim
28 words
A method of processing electrical signals as claimed in claim 2 in which the electrical signal corresponds to a power of the level of the acoustic emission activity.
Claim 7
Dependent Claim
28 words
A method of processing electrical signals as claimed in claim 5 in which the electrical signal corresponds to the square of the level of the acoustic emission activity.
Claim 8
Independent Claim
120 words
An apparatus for processing acoustic emissions in order to recognise features indicative of variations in a process producing the acoustic emissions comprising at least one transducer (12) acoustically coupled to a source process producing acoustic emissions and arranged to detect the acoustic emissions and to produce an electrical signal dependent upon the acoustic emission activity, a detector means (18) measures the mean value of the electrical signal, characterised in that a detector means (20) measures the minimum value of the electrical signal, a ratioing means (22) determines the ratio of the mean value of the electrical signal to the minimum value of the electrical signal, variations in said ratio are indicative of variations in the process producing the acoustic emissions.
Claim 9
Independent Claim
120 words
An apparatus for processing acoustic emissions in order to recognise features indicative of variations in a process producing the acoustic emissions comprising at least one transducer (12) acoustically coupled to a source process producing acoustic emissions and arranged to detect the acoustic emissions and to produce an electrical signal dependent upon the acoustic emission activity, a detector means (18) measures the mean value of the electrical signal, characterised in that a detector means (20) measures the minimum value of the electrical signal, a ratioing means (22) determines the ratio of the mean value of the electrical signal to the minimum value of the electrical signal, variations in said ratio are indicative of variations in the process producing the acoustic emissions.
Claim 10
Dependent Claim
31 words
An apparatus as claimed in claim 7 in which divider means (22) determine the ratio of the mean value of the electrical signal to the minimum value of the electrical signal.
Claim 11
Dependent Claim
88 words
An apparatus as claimed in claim 7 in which a first logarithmic amplifier means (40) produces the log of the mean value of the electrical signal, a second logarithmic amplifier means (42) produces the log of the minimum value of the electrical signal, subtractor means (44) subtracts the log of the minimum value of the electrical signal from the log of the mean value of the electrical signal to determine the ratio of the mean value of the electrical signal to the minimum value of the electrical signal.
Claim 12
Dependent Claim
122 words
An apparatus as claimed in claim 7 in which logarithmic amplifier means (52) produces the log of the electrical signal, the detector means (58) to measure the minimum value of the electrical signal measures the minimum value of the log of the electrical signal, the detector means (56) to measure the mean value of the log of the electrical signal measures the mean value of the log of the electrical signal, subtractor means (60) subtracts the minimum value of the log of the electrical signal from the mean value of the log of the electrical signal to determine the ratio of the mean value of the log of the electrical signal to the minimum value of the log of the electrical signal.
Claim 13
Dependent Claim
21 words
An apparatus as claimed in claim 7 in which the electrical signal corresponds to the intensity of the acoustic emission activity.
Claim 14
Dependent Claim
21 words
An apparatus as claimed in claim 7 in which the electrical signal corresponds to the level of the acoustic emission activity.
Claim 15
Dependent Claim
24 words
An apparatus as claimed in claim 7 in which the electrical signal corresponds to a power of the level of the acoustic emission activity.
Claim 16
Dependent Claim
24 words
An apparatus as claimed in claim 13 in which the electrical signal corresponds to the square of the level of the acoustic emission activity.
Claim 17
Dependent Claim
30 words
An apparatus as claimed in claim 7 in which the means to determine the ratio operates an alarm when the ratio is equal to or greater than a predetermined value.
Claim 18
Dependent Claim
25 words
An apparatus as claimed in claim 7 in which the means to determine the ratio sends a feedback signal to control the machine or process.
References Cited (Backward Citations)
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