CA1155684A - Method of sympton diagnosis by monitoring vibration of shaft of rotary machine - Google Patents
Method of sympton diagnosis by monitoring vibration of shaft of rotary machineInfo
- Publication number
- CA1155684A CA1155684A CA000374143A CA374143A CA1155684A CA 1155684 A CA1155684 A CA 1155684A CA 000374143 A CA000374143 A CA 000374143A CA 374143 A CA374143 A CA 374143A CA 1155684 A CA1155684 A CA 1155684A
- Authority
- CA
- Canada
- Prior art keywords
- symptom
- unusual
- rotary machine
- diagnosing
- shaft vibration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H1/00—Measuring characteristics of vibrations in solids by using direct conduction to the detector
- G01H1/003—Measuring characteristics of vibrations in solids by using direct conduction to the detector of rotating machines
-
- G—PHYSICS
- G07—CHECKING-DEVICES
- G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- G07C3/00—Registering or indicating the condition or the working of machines or other apparatus, other than vehicles
Abstract
ABSTRACT OF THE DISCLOSURE
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 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.
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 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.
Description
1 ~his invention relates to a method of monitoring a vibrational characteristic of the shaft of a rotary machine such as a turbo-generator of large capacity composed of a steam turbine and a generator installed in a thermo-electric or atomic power plant.
With the increase in the capacity of a rotary machine of the kind above described, monitoring of vibration of the shaft of the rotary machine becomes more and more important from the aspects of machine operation and maintenance. In a steam turbine of large capacity, for example, the phase of its shaft vibration tends to become more and more complex due to the various factors including the increased weight of the rotor, the increased center-to-center distance of the bearings and .: 15 the increased number of the turbine casings. Further, because of the recent tendency that such a rotary machine is more frequently started and stopped to meet varying power demand than the past, the possibility of occurrence of unusual shaft vibration attributable to, for example, a thermal unbalance is greater than when the rotary machine continues to operate under the steady condition. Therefore, a machine operator continually pays his attention to the operating state of the rotary machine, especially, in the starting stage of the rotary machine, because he must timely deal with ~ , 1 15t~684 l unusual vibration of the shaft if it occurs.
The present invention concerns with the art of monitoring shaft vibration of such a rotary machine so that the machine operator can make a quick response to unusual vibration of the shaft if it occurs. In the present invention, a symptom of unusual operation of the rotary machine is continuously diagnosed even when the rotary machine is operating steadily with the amplitude of shaft vibration or the rate of change of the amplitude being maintained within the so-called safety region, so that the result of symptom diagnosis can be quickly made use of as a guidance for ensuring the safety of the rotary machine.
A method commonly used hitherto for ensuring the safety of a rotary machine comprises continuously monitoring the amplitude itself of detected vibration of the shaft and generating an alarm signal as soon as the vibration amplitude exceeds a predetermined setting. This is a simplest method and is widely used in this field.
There is another method in which Fourier analysis is made on a vibrating waveform to extract a power spectrum of the waveform, as disclosed in, for example, United States Patent No. 3,694,637 entitled "Method and Apparatus for Detecting Tool Wear" and issued on September 26, 1972. According to the disclosure of the above patent, the detected power spectrum is compared with a reference power spectrum . ... : ~
''' ..
1 1556~
to estimate the time of replacement of a tool subjectcd to wear, and an improvement in the accuracy of monitoring is expected compared with the aforementioned method which relies upon only monitoring of the amplitude of thc detected shaft vibration signal.
There is still anothcr method disclosed in, for example, our U.S. Patent No. 4,302,813 which issued on November 24, 1981.
According to the method disclosed in the above patent appli-cation, a signal indicative of detected vibration of the shaft of a rotary machine is analyzed with respect to the machine's rotation frequency component and other frequency components having predetermined relationships with the former, and the results of analysis are used together with predetermined operation patterns for controlling the operation of the rotary machine. The method, in which the detected shaft vibration signal is subjected to digital analysis, is featured by the fact that the accuracy of monitoring can be improved over that based on monitoring of an analog signal and that the method is applied to the control of the operation of a rotary machine.
Although all of these prior art disclosures are adapted to make monitoring of the amplitude of shaft vibration or monitoring of the machine's rotation frequency and associated frequency components, monitoring . , ~
.
,.~ .
: ' . . ' ~ ' ' ' , . . .
1 ~55~4 1 of the machine operation within the so-called safety region is not especially taken into consideration in the prior art disclosures.
It is an object of the present invention to provide a method of diagnosing a symptom of unusual operation of a rotary machine on the basis of a signal indicative of detected vibration of the shaft of the rotary machine.
Another object of the present invention is to provide a method of the above character in which such a symptom is diagnosed at a safety level of the detected shaft vibration signal used for the control of the operation o~ the rotary machine so as to provide operation data which can be utilized more adequately as information required for the machine operation control purpose.
The method according to the present invention is featured by the fact that, in a stage in which a signal indicative of detected vibration of the shaft of a rotary machine has a level lower than an alarm level and, therefore, the detected signal level lies within a safety region, a symptom of unusual operation of the rotary machine is diagnosed by detecting subsequent changes in the amplitude of the shaft vibration signal.
Another feature of the present invention resides in the fact that the symptom of unusual operation of the , rotary machine is diagnosed on the basis of the ampli-tude of the detected shaft vibration signal and the rate i~.
` - It -:, ., . ~
, . ' . ' ' of change of the vibration amplitude.
Still another feature of the present invention resides in the fact that a symptom diagnostic level at a given time is set on the basis of the amplitude of the shaft vibration and the rate of change of the vibration amplitude detected at that time, and the symptom of unusual operation of the rotary machine is diagnosed by comparing the signal level detected at the next time with the setting of the sympton diagnostic level.
Yet another feature of the present invention resides in the fact that the amplitude of the detected shaft vibration signal and the rate of change of the vibration amplitude are selected to be equal to each other thereby defining a circular region for the symptom diagnosis, and the symptom of unusual operation of the rotary machine is diagnosed by detecting whether or not the signal amplitude and the rate of change of the signal amplitude lie inside or outside of this circular symptom diagnostic region.
In accordance with one aspect of the invention there is provided in a method of diagnosing an unusual symptom during a region of a safe operation in which an amplitude value of a shaft vibration signal of a rotary ` machine is smaller than a predetermined value, and a change ratio of the shaft vibration signals is smaller than a predetermined value, a method of diagnosing an .: .
unusual symptom by monitoring the shaft vibration of the ` rotary machine characterized by the steps of: detecting `:~ B
:
. :
.
the amplitude value of the ~shaft vibration signal and the change ratio of the shaft vibration signals, at a pre-determined diagnosing period, setting and memorizing an absolute value of a predetermined change from the amplitude value and the change ratio of said shaft vibration signals respectively, which are detected at the nth diagnosing period, for the purpose of using said absolute value as a reference value for deciding an unusual symptom at the (n+l)th diagnosing period, calculating the absolute value of deviations between the amplitude value and the change ratio thereof of the shaft vibration signals at the (n+l) diaynosing period, and the amplitude value and the change ratio thereof of the shaft vibration signals at the nth diagnosing period respectively, and determining the presence of a symptom of unusual operation of said rotary machine when at least one of the calculated variations exceeds the set and memorized value of the reference value.
In accordance with another aspect of the invention there is provided in an apparatus for diagnosing an unusual ~: 20 symptom during an usual operation of a rotary machine by ; detecting and monitoring shaft vibration signals due to the rotation of said rotary machine, an apparatus for diagnosing an unusual symptom characterized by timing signal generating means for generating timing signals for diagnosing the unusual symptom during said usual operation of said rotary machine; first and second memory means for memorizing the amplitude signals of said shaft vibration . signals in response to the timing signal at the nth and ~ , r'.' '`
. ~
,; .' ' :
1 1S56~4 (n+l)th unusual symptom diagnosing periods; third and fourth memory means for memorizing the change rate of the amplitude of said shaft vibration signals in response to the timing signal at the nth and (n+l)th unusual symptom diagnosing periods; determination-reference memory means ` for setting and memorizing the change of the amplitude value and the change rate of the amplitude value of said shaft vibration signals which are detected as a deter-mination reference for the unusual symptom diagnosis, at the (n+l)th unusual symptom diagnosing period, in the nth 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 of said first calculation means with the change of said amplitude value memorized in said determination-reference memory means; and second comparing means for comparing the ; 20 calculation results of said second calculation means with the change of said change rate of the amplitude value memorized in said determination-reference memory means;
wherein the presence of a symptom of unusual operation of : said rotary machine is detected when at least either one of the outputs of said first and second comparing means exceeds the change set in said determination-reference memory means.
Other objects, features and advantages of the - 6a -' ' . .
present invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings, in which~
Fig. lA is a schematic front elevation view of a rotary machine for which the shaft vibration is to be monitored;
Fig. lB shows a shaft vibration transducer - mounted on each of the bearings in the rotary machine shown in Fig. lA;
Fig. lC is a schematic view showing the structure of a reference pulse generator and a rotation speed-responsive pulse generator;
Fig. 2 is a block diagram of a shaft vibration monitoring system;
Fig. 3A illustrates the relation among a safety region, an alarm region and a trip region when the rotation speed of the rotary machine is divided into a ;, , ;, ,:
7 - 6b -': ` : ~ ;':
1 ~ 556~4 plurality of ranges;
Fig. 3B illustrates thc corresponding regions of Fig. 3A
divided depending on the rotation speed of thc rotary machine;
Fig. 4 illustratcs margins of various points in the safety rcgion relative to the alarm region;
Fig. 5 illustrates thc locus of a symptom diagnostic rcgion renewed at time intervals of a predetermined symptom diagnostic period;
Fig. 6 is a block diagram of a shaft vibration monitoring system including the parts embodying the method according to the present invention;
` Fig. 7A shows the detailed structure of the symptom diagnostic unit 30 shown in Fig. 6 and embodying the feature of the present invention;
Figs. 7B to 7E show partial modifications of the struc- -ture shown in Fig. 7A;
Fig. 8 (appearing on the same sheet of drawings as ; Fig. 6) illustrates the symptom diagnostic region established according to the present invention;
Figs. 9A to 9H show a timing chart illustrating the operation of the symptom diagnostic unit 30 shown in Fig. 7A;
~; Figs. lOA to lOC illustrate other forms of the symptom diag~ostic region shown in Fig. 8; and Figs. llA and llB show another embodiment of the present ' invention adapted to perform a predictive symptom diagnosis.
Before describing the present invention in ~ 1556~4 ; 1 detail, the structure of a rotary machine to which the present invention is applied, a transducer transducing vibration of the shaft of the rotary machine, and pulse generators will be briefly described with reference to Figs. lA, lB and lC.
Referring to Fig. lA, the rotor shaft of the rotary machine is journalled in bearings 1 to 6. The ; rotary machine includes a high-pressure turbine HP, an intermediate-pressure turbine IP and a low-pressure turbine LP driving a generator. A vibration transducer 12 as shown in Fig. lB is mounted on each of the bearings 1 to 6. Referring to Fig. lB, the vibration transducer 12 engages with the rotor shaft 11 of the rotary machine to transduce vibration of the rotor shaft 11 into an electrical signal 101 indicative of vibration ~, of the rotor shaft 11, and an amplifier 13 amplifies the detected shaft vibration signal 101. Referring to Fig. lC, a reference pulse generator includes a gear 7 mounted on one end of the rotor shaft 11, an associated electromagnetic pickup 9 and an amplifier 25 connected ; to the pickup 9 to provide a reference pulse signal 105, ; and a rotation-speed responsive pulse generator includes a gear 8 mounted also on one end of the rotor shaft 11, an associated electromagnetic pickup 10 and an ampli-fier 26 connected to the pickup 10 to provide a rotation speed-responsive pulse signal 106. The former pulse generator generates a predetermined number of pulses per revolution of the rotor shaft 11, while the latter :` ::
i ~ 1556~4 1 generates one pulse per revoluticn of the rotor shaft 11.
It is generally convenient that the former pulse generator generates 60 pulses per revolution of the rotor shaft 11.
Fig. 2 is a block diagram of one form of a system preferably used for monitoring the transducer output signal 101 indicative of vibration of the asso-ciated portion of the rotor shaft 11. Referring to Fig.
With the increase in the capacity of a rotary machine of the kind above described, monitoring of vibration of the shaft of the rotary machine becomes more and more important from the aspects of machine operation and maintenance. In a steam turbine of large capacity, for example, the phase of its shaft vibration tends to become more and more complex due to the various factors including the increased weight of the rotor, the increased center-to-center distance of the bearings and .: 15 the increased number of the turbine casings. Further, because of the recent tendency that such a rotary machine is more frequently started and stopped to meet varying power demand than the past, the possibility of occurrence of unusual shaft vibration attributable to, for example, a thermal unbalance is greater than when the rotary machine continues to operate under the steady condition. Therefore, a machine operator continually pays his attention to the operating state of the rotary machine, especially, in the starting stage of the rotary machine, because he must timely deal with ~ , 1 15t~684 l unusual vibration of the shaft if it occurs.
The present invention concerns with the art of monitoring shaft vibration of such a rotary machine so that the machine operator can make a quick response to unusual vibration of the shaft if it occurs. In the present invention, a symptom of unusual operation of the rotary machine is continuously diagnosed even when the rotary machine is operating steadily with the amplitude of shaft vibration or the rate of change of the amplitude being maintained within the so-called safety region, so that the result of symptom diagnosis can be quickly made use of as a guidance for ensuring the safety of the rotary machine.
A method commonly used hitherto for ensuring the safety of a rotary machine comprises continuously monitoring the amplitude itself of detected vibration of the shaft and generating an alarm signal as soon as the vibration amplitude exceeds a predetermined setting. This is a simplest method and is widely used in this field.
There is another method in which Fourier analysis is made on a vibrating waveform to extract a power spectrum of the waveform, as disclosed in, for example, United States Patent No. 3,694,637 entitled "Method and Apparatus for Detecting Tool Wear" and issued on September 26, 1972. According to the disclosure of the above patent, the detected power spectrum is compared with a reference power spectrum . ... : ~
''' ..
1 1556~
to estimate the time of replacement of a tool subjectcd to wear, and an improvement in the accuracy of monitoring is expected compared with the aforementioned method which relies upon only monitoring of the amplitude of thc detected shaft vibration signal.
There is still anothcr method disclosed in, for example, our U.S. Patent No. 4,302,813 which issued on November 24, 1981.
According to the method disclosed in the above patent appli-cation, a signal indicative of detected vibration of the shaft of a rotary machine is analyzed with respect to the machine's rotation frequency component and other frequency components having predetermined relationships with the former, and the results of analysis are used together with predetermined operation patterns for controlling the operation of the rotary machine. The method, in which the detected shaft vibration signal is subjected to digital analysis, is featured by the fact that the accuracy of monitoring can be improved over that based on monitoring of an analog signal and that the method is applied to the control of the operation of a rotary machine.
Although all of these prior art disclosures are adapted to make monitoring of the amplitude of shaft vibration or monitoring of the machine's rotation frequency and associated frequency components, monitoring . , ~
.
,.~ .
: ' . . ' ~ ' ' ' , . . .
1 ~55~4 1 of the machine operation within the so-called safety region is not especially taken into consideration in the prior art disclosures.
It is an object of the present invention to provide a method of diagnosing a symptom of unusual operation of a rotary machine on the basis of a signal indicative of detected vibration of the shaft of the rotary machine.
Another object of the present invention is to provide a method of the above character in which such a symptom is diagnosed at a safety level of the detected shaft vibration signal used for the control of the operation o~ the rotary machine so as to provide operation data which can be utilized more adequately as information required for the machine operation control purpose.
The method according to the present invention is featured by the fact that, in a stage in which a signal indicative of detected vibration of the shaft of a rotary machine has a level lower than an alarm level and, therefore, the detected signal level lies within a safety region, a symptom of unusual operation of the rotary machine is diagnosed by detecting subsequent changes in the amplitude of the shaft vibration signal.
Another feature of the present invention resides in the fact that the symptom of unusual operation of the , rotary machine is diagnosed on the basis of the ampli-tude of the detected shaft vibration signal and the rate i~.
` - It -:, ., . ~
, . ' . ' ' of change of the vibration amplitude.
Still another feature of the present invention resides in the fact that a symptom diagnostic level at a given time is set on the basis of the amplitude of the shaft vibration and the rate of change of the vibration amplitude detected at that time, and the symptom of unusual operation of the rotary machine is diagnosed by comparing the signal level detected at the next time with the setting of the sympton diagnostic level.
Yet another feature of the present invention resides in the fact that the amplitude of the detected shaft vibration signal and the rate of change of the vibration amplitude are selected to be equal to each other thereby defining a circular region for the symptom diagnosis, and the symptom of unusual operation of the rotary machine is diagnosed by detecting whether or not the signal amplitude and the rate of change of the signal amplitude lie inside or outside of this circular symptom diagnostic region.
In accordance with one aspect of the invention there is provided in a method of diagnosing an unusual symptom during a region of a safe operation in which an amplitude value of a shaft vibration signal of a rotary ` machine is smaller than a predetermined value, and a change ratio of the shaft vibration signals is smaller than a predetermined value, a method of diagnosing an .: .
unusual symptom by monitoring the shaft vibration of the ` rotary machine characterized by the steps of: detecting `:~ B
:
. :
.
the amplitude value of the ~shaft vibration signal and the change ratio of the shaft vibration signals, at a pre-determined diagnosing period, setting and memorizing an absolute value of a predetermined change from the amplitude value and the change ratio of said shaft vibration signals respectively, which are detected at the nth diagnosing period, for the purpose of using said absolute value as a reference value for deciding an unusual symptom at the (n+l)th diagnosing period, calculating the absolute value of deviations between the amplitude value and the change ratio thereof of the shaft vibration signals at the (n+l) diaynosing period, and the amplitude value and the change ratio thereof of the shaft vibration signals at the nth diagnosing period respectively, and determining the presence of a symptom of unusual operation of said rotary machine when at least one of the calculated variations exceeds the set and memorized value of the reference value.
In accordance with another aspect of the invention there is provided in an apparatus for diagnosing an unusual ~: 20 symptom during an usual operation of a rotary machine by ; detecting and monitoring shaft vibration signals due to the rotation of said rotary machine, an apparatus for diagnosing an unusual symptom characterized by timing signal generating means for generating timing signals for diagnosing the unusual symptom during said usual operation of said rotary machine; first and second memory means for memorizing the amplitude signals of said shaft vibration . signals in response to the timing signal at the nth and ~ , r'.' '`
. ~
,; .' ' :
1 1S56~4 (n+l)th unusual symptom diagnosing periods; third and fourth memory means for memorizing the change rate of the amplitude of said shaft vibration signals in response to the timing signal at the nth and (n+l)th unusual symptom diagnosing periods; determination-reference memory means ` for setting and memorizing the change of the amplitude value and the change rate of the amplitude value of said shaft vibration signals which are detected as a deter-mination reference for the unusual symptom diagnosis, at the (n+l)th unusual symptom diagnosing period, in the nth 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 of said first calculation means with the change of said amplitude value memorized in said determination-reference memory means; and second comparing means for comparing the ; 20 calculation results of said second calculation means with the change of said change rate of the amplitude value memorized in said determination-reference memory means;
wherein the presence of a symptom of unusual operation of : said rotary machine is detected when at least either one of the outputs of said first and second comparing means exceeds the change set in said determination-reference memory means.
Other objects, features and advantages of the - 6a -' ' . .
present invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings, in which~
Fig. lA is a schematic front elevation view of a rotary machine for which the shaft vibration is to be monitored;
Fig. lB shows a shaft vibration transducer - mounted on each of the bearings in the rotary machine shown in Fig. lA;
Fig. lC is a schematic view showing the structure of a reference pulse generator and a rotation speed-responsive pulse generator;
Fig. 2 is a block diagram of a shaft vibration monitoring system;
Fig. 3A illustrates the relation among a safety region, an alarm region and a trip region when the rotation speed of the rotary machine is divided into a ;, , ;, ,:
7 - 6b -': ` : ~ ;':
1 ~ 556~4 plurality of ranges;
Fig. 3B illustrates thc corresponding regions of Fig. 3A
divided depending on the rotation speed of thc rotary machine;
Fig. 4 illustratcs margins of various points in the safety rcgion relative to the alarm region;
Fig. 5 illustrates thc locus of a symptom diagnostic rcgion renewed at time intervals of a predetermined symptom diagnostic period;
Fig. 6 is a block diagram of a shaft vibration monitoring system including the parts embodying the method according to the present invention;
` Fig. 7A shows the detailed structure of the symptom diagnostic unit 30 shown in Fig. 6 and embodying the feature of the present invention;
Figs. 7B to 7E show partial modifications of the struc- -ture shown in Fig. 7A;
Fig. 8 (appearing on the same sheet of drawings as ; Fig. 6) illustrates the symptom diagnostic region established according to the present invention;
Figs. 9A to 9H show a timing chart illustrating the operation of the symptom diagnostic unit 30 shown in Fig. 7A;
~; Figs. lOA to lOC illustrate other forms of the symptom diag~ostic region shown in Fig. 8; and Figs. llA and llB show another embodiment of the present ' invention adapted to perform a predictive symptom diagnosis.
Before describing the present invention in ~ 1556~4 ; 1 detail, the structure of a rotary machine to which the present invention is applied, a transducer transducing vibration of the shaft of the rotary machine, and pulse generators will be briefly described with reference to Figs. lA, lB and lC.
Referring to Fig. lA, the rotor shaft of the rotary machine is journalled in bearings 1 to 6. The ; rotary machine includes a high-pressure turbine HP, an intermediate-pressure turbine IP and a low-pressure turbine LP driving a generator. A vibration transducer 12 as shown in Fig. lB is mounted on each of the bearings 1 to 6. Referring to Fig. lB, the vibration transducer 12 engages with the rotor shaft 11 of the rotary machine to transduce vibration of the rotor shaft 11 into an electrical signal 101 indicative of vibration ~, of the rotor shaft 11, and an amplifier 13 amplifies the detected shaft vibration signal 101. Referring to Fig. lC, a reference pulse generator includes a gear 7 mounted on one end of the rotor shaft 11, an associated electromagnetic pickup 9 and an amplifier 25 connected ; to the pickup 9 to provide a reference pulse signal 105, ; and a rotation-speed responsive pulse generator includes a gear 8 mounted also on one end of the rotor shaft 11, an associated electromagnetic pickup 10 and an ampli-fier 26 connected to the pickup 10 to provide a rotation speed-responsive pulse signal 106. The former pulse generator generates a predetermined number of pulses per revolution of the rotor shaft 11, while the latter :` ::
i ~ 1556~4 1 generates one pulse per revoluticn of the rotor shaft 11.
It is generally convenient that the former pulse generator generates 60 pulses per revolution of the rotor shaft 11.
Fig. 2 is a block diagram of one form of a system preferably used for monitoring the transducer output signal 101 indicative of vibration of the asso-ciated portion of the rotor shaft 11. Referring to Fig.
2, the detected shaft vibration signal 101 is applied through the amplifier 13 to a detector circuit 20 which provides an output signal (a DC component signal) indicative of the average value of the ampoitude A of the input signal 101. The detector output signal indicative of the vibration amplitude A is applied to a monitoring circuit 24 and to a differentiating circuit 22 which provides an output signal indicative of ~ the rate of change A of the vibration amplitude. The - pulse signal 105 or 106 indicative of the rotation speed N of the rotary mac-ine is also applied from thepulse generator to the monitoring circuit 24. The signal 105 ' 20 or 106 may, however, be any one of other signals propor-tional to the rotation speed of the rotary machine.
: A method as illustrated in Fig. 3A has been proposed so as to diagnose unusual vibration of the rotor shaft 11 of the rotary machine on the basis of the relation between the vibration amplitude A and the rotation speed N of the rotary machine. Referring to Fig. 3A, there are shown an alarm region, a trip region and a safety region related to the rotation speed N
_ 9 _ - ~1556~
1 of the rotary machine. In the alarm region, the relations Al < A < A2, A3 < A < A4 and A5 < A < A6 hold when the rotation speed N lies within the ranges of 0 < N ~ Nl, Nl < N < N2 and N2 ~ N < N3 respectively. In the trip region, the relations A2 ~ A, A4 < A and A5 < A hold ; when the rotation speed N lies within the above ranges respectively. In the safety region, the relations 0 < A < Al, 0 < A < A3 and 0 < A < A5 hold when the rotation speed N lies within the above ranges respectively.
Besides the above method of monitoring the shaft vibration by dividing the rotation speed range into a plurality of ranges as shown in Fig. 3A, there is another method in which the shaft vibration is monitored on the basis of continuous functions fl(N) and f2(N) of the rotation speed N of the rotary machine. In Fig. 3B, the relation fl(N) < A < f2(N) holds in an alarm region, the relation f2(N) < A holds in a trip region, and the relation A < fl(N) holds in a safety reglon. In each of these prior art methods, no monitoring is done on the behaviour of the amplitude of vibration lying within the safety region. The prior art methods are therefore defective in that a predictive diagnosis of a symptom of unusual operation of the rotary machine cannot be ` expected although such a symptom may have already appeared in the safety region.
The present invention contemplates to make an adequate diagnosis of the operating condition of the rotary machine by quickly detecting appearance of a 6~4 1 symptom of unusual operation of the rotary machine in the safety region.
More precisely, the present invention is featured by the fact that the state of vibration of the rotor shaft of the rotary machine is monitored while the amplitude of vibration lies still within the safety region by establishing a safety behavious region within ; the safety region on the basis of the present status of ` the amplitude of vebration and the rate of change of the amplitude of vibration, renewing the sa~ety behaviour region in response to a change of the status of the amplitude of vibration and the rate of change of the vibration amplitude, and detecting appearance of a symptom of unusual operation of the rotary machine when the amplitude of vibration and/or the rate of change of the vibration amplitude exceed the individual values of the safety behaviour region.
Describing in further detail, the safe~y region is commonly determined on the basis of the relation between the vibration amplitude A and the rate of change of the vibration amplitude A in a manner as shown in Fig. 4. It will be seen in Fig. 4 that the relations A ~ Al and A < Al hold in the safety region. Consider now a point Pl in the safety region. There are margins of Pl x in the vibration amplitude change rate A and Pl y in the vibration amplitude A until the point Pl moves out into the alarm region from the safety region. On the other hand, in the case of another point P2 lying `` 11556~4 1 also within the safety region, it has a margin of P2 x in the vibration amplitude change rate A and a margin of P2 y in the vibration amplitude A. Similarly, in the case of still another point P3 lying within the safety region, it has a margin of P3 x in the vibration amplitude change rate A and a margin of P3 y in the vibration amplitude A. It will be seen that the margin P2 y is larger than the margin P2 x in the case of the point P2, while the margin P3 x is larger than the ~;10 margin P3 y in the case of the point P3. Thus, in the case of the point P3, it has been considered that an abrupt change in the vibration amplitude change rate A
will not move the point P3 out of the safety region and the point P3 will still remain within the safety region.
Similarly, in the case of the point P2, it has been ;considered that an abrupt change in the vibration amplitude A will not move the point P2 out of the safety region and the point P2 will still remain within the `-safety region. There have thus been no means for recognizing such a status, and these points have been judged to remain within the safety region in spite of a possible abrupt change in the status. It has therefore been impossible to recognize future behaviour of these points lying within the safety region:
The present invention contemplates to detect a sympton of unusual operation of the rotary machine while the points lie still within the safety region.
Fig. 5 shows schematically the basic concept of the .' `" .
... .
1 ~556~
., 1 present invention for detecting a symptom of unusual - operation of the rotary machine by recognizing future behaviour of the points Pl, P2 and P3. Referring to , Fig. 5, symptom diagnostic regions for the individual points Pl, P2 and P3 are established within the safety region, and appearance of a symptom of unusual operation ` of the rotary machine is predicted or estimated when any one of the points Pl, P2 and P3 moves out of its symptom diagnostic region. In Fig. 5, these regions are shown concentric with respect to the individual points Pl, 2 and P3.
Fig. 6 is a block diagram showing the general structure of a shaft vi~ration monitoring system includ-ing the parts emobying the method according to the present invention. Referring to Fig. 6, a detector circuit 20 corresponds to that shown in Fig. 2, and a shaft vibration signal 101 is applied thereto from the vibration transducer 12 shown in Fig. lB. A pulse generator 23 corresponds to that shown in Fig. lC. A
function generator 21 generates an output signal Ar indicative of a function fl(N) of the rotation speed N
of the rotary machine in response to the application of the pulse signal from the rotation speed-responsive pulse generator. A differentiation (dA/dt) circuit 22 corresponding to that shown in Fig. 2 generates an output signal indicative of the vibration amplitude change rate A. A first level comparator 31 compares the level of the output signal of the detector circuit 20 -` 11S56~
1 indicative of the detected vibration amplitude A with that of the output signal Ar of the function generator 21 and generates an alarm signal or a trip signal 33 when the relation A ~ Ar holds. A second level comparator 5 16 compares the level of the output signal of the dif-ferentiator 22 indicative of the detected vibration amplitude change rate A with a predetermined setting Ar of the vibration amplitude change rate A and generates an alarm signal 18 when the relation A ~ Ar holds.
s 10 Thus, both of the vibration amplitude A and its change rate A are monitored at the same time. Such an arrange-, ment is, however, still insufficient in that nothing is done until the level of the setting Ar or Ar is reached.
A symptom diagnostic unit 30 ls the charac-15 teristic part of the present invention. Fig. 7A shows the detailed structure of one form of the symptom diagnostic unit 30, and Fig. 8 illustrates the basic principle of symptom diagnosis according to the present invention.
Suppose now that Po(Ao, Ao) is the monitored point determined from the values of A and A lying within the safety region. Suppose then that allowable changes of A and A at the point PO sub~ected to the symptom diagnosis are set at ~AL and ~AL. The symptom diagnostic region S at that time is expressed by the following equation (1):
1 1556~
(A - Ao)2 (A - A )2 ,~ 2 2 = 1 ............................ (1) ~A ~A
L L
1 The symptom diagnostic region S is circular as shown in Fig. 8 when ~AL and ~AL are selected to be ~AL = QAL.
Since ~AL and ~AL represent increments of A and A
respectively during the symptom diagnostic period ~t, they can be expressed by the differences {A (t + ~t) -A (t)} and {A (t + ~t) - A (t)} resp~ctively. When the : point PO moves to the point Pl lying also within the symptom diagnostic region S at the time (t + ~t), that is, when the following expression Pl {A (t + ~t), A (t + ~t)} ~ S ' (2) ' holds, a new symptom diagnostic region S is established by selecting this point Pl as a new origion. If the relation Pl ~ S holds, this proves appearance of a symptom of unusual operation of the rotary machine, and an unusual symptom signal is generated. In this manner, symptom diagnosis can be carried out even when the point P lies still within the safety region.
The detailed structure of the symptom diag-nostic unit 30 according to the present invention will now be described with reference to Fig. 7A. The symptom diagnostic period Tsy is provided by a symptom diagnostic - timing signal ~fsy) generator 50. This symptom ~ 15 -1 1556~4 1 diagnostic period T provided by the symptom diagnostic timing signal generator 50 is selected independently of, for example, the sampling period for digital processing of the shaft vibration signal 101. The diagnostic timing is determined in relation to the symptom diagnostic region S (or ~AL and QAL) described above. When the symptom diagnostic period Tsy is excessively long, the significance of symptom diagnosis will be lost, while when it is excessively short, true symptom diagnosis may not be attained. Therefore, Tsy (or fsy) shown in Fig.
9A is determined depending on whether the symptom diagnosis is directed to the operating characteristic of the rotary machine under consideration or to the operat-ing condition under acceleration of the rotary machine or to the steady operating condition of the rotary machine.
The data receiving pulse fsy shown in Fig. 9A
is generated from the symptom diagnostic timing signal generator 50 in each symptom diagnostic period Tsy to permit passage of data A and A through respective gate circuits 52 and 62. The data A and A are then applied to respective registers (I) 54 and (I) 64 in timed relation with a timing pulse Pl shown in Fig. 9B, and the next data A and A are applied to respective registers (II) 56 and (II) 66 in timed relation with another timing pulse P2 shown in Fig. 9C. Fig. 9D shows the ` timing of renewal of the data A and A registered in the respective registers (I) 54, 64 and (II) 56, 66. The :
. -`- 11556~4 ... .
1 term "renewal" indicates that the data A and A are sequentially alternately registered in the respective registers (I) 54, 64 and (II) 56, 66 so that newest ` data can be used for the purpose of symptom diagnosis.
Fig. 9E shows how the symptom is diagnosed using the data A and A registered in the respective registors (I) and (II), and it will be seen that the symptom diagnosis is repeated as shown by the steps SYMPl to SYMPn. For example, diagnostic calculation using the data A and A
registered in the respective registers (I) and (II) is executed in the step SYMPl, and in the next step SYMP2, diagnostic calculation is executed using the data registered in the registers (II) and used already in the step SYMPl together with the new data registered now in the registers (I).
Referring to Fig. 7A again, the data A regis-tered at time t in the register (I) 54 and the data A
registered at time (t + ~t) in the register (II) 56 are applied to a difference calculating circuit (I) 58 which calculates the difference ~A between the inputs, and the calculated difference ~A is applied from the calculat-ing circuit (I) 58 to a deviation calculating circuit (I) 60 which calculates a deviation of ~A from ~AL.
The result of calculation is applied from the deviation calculating circuit (I) 60 to a selective output circuit 75. Similarly, the data A registered at time t in the register (I) 64 and the data A registered at time (t + ~t) in the register (II) 66 are applied to a 1 ~556 :' 1 difference calculating circuit tII~ 68 which calculates ; the difference ~A between the inputs, and the calculated difference ~A is applied from the calculating circuit (II) 68 to a deviation calculating circuit (II) 70 which calculates a deviation of ~A from ~AL. The result of calculation is also applied from the deviation calculat-ing circuit (II) 70 to the selective output circuit 75.
Therefore, the term "diagnostic calculation"
referred to above is used to include the difference calculation executed in the difference calculating clrcuits (I) 58 and (II) 68, and the deviation calcula-tion executed in the deviation calculating circuits (I) 6C and (II) 70 which apply the results of calculation to the selective output circuit 75. When, for example, the difference between the value of A detected at time (t + ~t) and that of A detected at time t does not exceed the value of ~AL, that is, when A(t + ~t) - A(t) ~ ~AL ------------- (3), a symptom signal al as shown in Fig. 9F appears from the selective output circuit 75. When, similarly, the . 20 difference between the value of A detected at time (t + ~t) and that of A detected at time t exceeds the value of ~AL, that is, when A(t + ~t) - A(t) ~ ~AL (4)' l a symptom signal al as also shown in Fig. 9F appears from the selective output circuit 75. It will be seen in Fig. 9F that an output signal from the selective output circuit 75 is shown by the solid waveform when the difference ~A or ~A above described exceeds the ; setting defining the region S, and another output signal is shown by the dotted waveform when the difference ~A
or ~A does not exceed the setting defining the region S.
Thus, the symptom signals al, a3, an_l, an_l and an indicate that the setting is exceeded. These symptom signals are sequentially applied from the selective output circuit 75 to a memory 80 and to an accumulative counter 82 shown in Fig. 7A. These data are sequentially stored in the memory 80 to be utilized for the analysis of the operating condition of the rotary machine.
The accumulative counter 82 counts the symptom signals shown in Fig. 9F, and, when the count attains a predetermined setting Csy, it generates an alarm signal M. Fig. 9G shows the progressive increase of the count of the counter 82 until the count attains the setting Csy at time ta at which the alarm signal M shown in Fig. 9H is generated. The counter 82 is reset at time tcr after counting the pulses for a predetermined period of time and is then set to start its counting operation again.
The values of ~AL and ~AL defining the symptom diagnostic region S may be fixed. However, it is common practice that these values are suitably adjustable by .
: ` 11S56~4 1 a symptom diagnostic region setting circuit 90 shown in Fig. 7A. This symptom diagnostic region setting circuit 90 may be manually controlled for the purpose of manual setting of the values of ~AL and ~AL or an external setting signal Ex may be applied to this circuit 90 for suitably externally setting the values of ~AL and ~AL.
Although the counter 82 is adapted to make an accumulative counting operation as shown in Fig. 9G, the symptom signal a or a applied to the counter 82 may be suitably weighted, as, for example, shown in Fig. 7B. Referring to Fig. 7B, a weighting element 84 is disposed in a signal path extending between the selective output circuit 75 and the counter 82 to multiply the signal a or a by a suitable weight W. For this purpose, a coefficient unit of simple structure can be used. It is a matter of choice to multiply the signal a by the weight W or to multiply the signal a by the weight W.
In the deviation calculating circuits (I) 60 and (II) 70~ deviations of ~A from ~AL and ~A from ~AL
are calculated. However, the ratios therebetween may be calculated by a circuit as, for example, shown in Fig.
7C. Referring to Fig. 7C, each of the circuits 60 and 70 is modified to include a ratio calculating circuit 86 and a comparator 88. The ratio calculating circuits 86 calculate the ratios ~A/~AL and ~A/~AL respectively, and each of the comparators 88 compares the result of calculation by the associated ratio calculating circuit 1 1556~4 1 86 with unity Therefore, when the result of comparison proves that ~A/aAL ~ 1.0 or ~A~AL ~ 1.0, a symptom signal a or a as shown in Fig. 9F is applied to the counter 82.
In the form shown in Fig. 8, the symptom diagnostic region S is defined to be a circle depicted around a point Po(Ao, Ao). However, the shape of the symptom diagnostic region S is in no way limited to the circle shown in Fig. 8. Thus, the relation between aAL
and aAL may be ¦QAL¦ ~ ¦aAL¦. For example, the shape of the symptom diagnostic region S may be elliptical as shown in Fig. lOA. In such a case, lt is effective to determine the shape of the region S in relation to the direction of progressive movement of the point P. The ; 15 shape of the symptom diagnostic region S may be sectoral as shown in Fig. lOB. In such a case, judgment may be made as to whether Pl ~ S, and a symptom signal may be generated when Pl ~ S.
Fig. lOC shows that the progressive movement of point P from, for example, PO to P5 is traced, and the safety region is divided into, for-example, a plurality of small symtom diagnostic regions Sl to S12.
When, for example, the result of symptom diagnosis at time intervals of the symptom diagnostic period Tsy proves that the point P has progressively moved from PO
1' P2, P3 and P4 as shown in Fig. lOC, judgment is made as to how many such small symptom diagnostic regions have been passed until finally the .
~,~
' ` 11556~4 1 point P5 is reached. In the case of Fig. lOC, the number of the small symptom diagnostic regions through which the point P has passed is five. In the method of symptom diagnosis shown in Fig. lOC, the presence of a symptom of unusual operation of the rotary machine is diagnosed when the number of the small symptom diagnostic regions through which the point P has passed is larger than a predetermined setting. When such a number is smaller than the predetermined setting, the operating condition of the rotary machine is relatively stable, and the result of symptom diagnosis proves that there is no symptom of unusual operation of the rotary machine.
Figs. llA and llB show another embodiment of the method according to the present invention. Referring to Fig. llA, a vibration amplitude value A(t) at time t is predicted or estimated on the basis of similar values A(t - ~t) and A(t - 2~t), and the deviation QA~t) of A(t) from A(t) is monitored. The following equation holds .. , ~A(t) = A(t) - A(t) ........................... C5) = A(t) - {A(t - ~) + A(t - ~t) - A(t - 2~t)}
= A(t) - 2A(t - ~t) + A(t - 2~t) And, the presence of a symtom of unusual operation of the rotary machine is diagnosed when the following .
` 11556~4 1 relation holds:
~A(t) > 0 ...................... t6) According to this method, the vibration amplitude value Att) at time t is estimated utilizing the data obtained at time (t - ~t) and at time (t - 2~t), and the presence of a symptom of unusual operation of the rotary machine is diagnosed when ~A(t) is equal to or larger than 0. This method is thus effective for the diagnosis of the tendency of changing vibration.
In lieu of the method just described, a change of the vibration amplitude difference may be monitored.
For example, the infinitesimal change ~A'(t) of the vibration amplitude difference in Fig. llA is given by ~A'(t) = {A(t) - A(t -Qt)} - {A(t - Qt) - A(t - 2~t)}
= A(t) - 2A(t - ~t) + A(t - 2~t) ...... (7) Therefore, ~A'(t) can be estimated by linear approxima-tion, and this manner of symptom diagnosis is as effective as that described with reference to Fig. llA. The principle of symptom diagnosis above described applies also to A. Herein, the method of symptom diagnosis on the detected vibration amplitude A will be described with reference to Fig. llB, by way of example. Referring to Fig- llB, a predictive symptom diagnostic unit 100 is ! connected at its inputs to the registers (I) 64 and 1 1 556~4 1 (II) 66 and at its output to the selective output circuit 75 and includes a predictive information register 102 which stores a plurality of data required for the predictive symptom diagnosis. For the purpose of predictive symptom diagnosis of the vibration amplitude A described with reference to Fig. llA, the register 102 may have a capacity of registering at least three data since A(t) is estimated on the basis of the data A(t - ~t) and A(t - 2~t). The contents of the register 102 are sequentially renewed by the data sampled at time intervals of the symptom diagnostic period Tsy. A
predictive calculating circuit 104 calculates the estimated vibration amplitude value A(t) at time t on the basis of the data A(t - ~t) and A(t - 2~t) registered in the register 102. A comparator 106 executes the calculation of QA(t) according to, for example, the equation (5), and an evaluating circuit 108 evaluates whether the relation ~A(t) > 0 shown in the expression (6) holds or not. The presence of a symptom of unusual operation of the rotary machine is diagnosed ` when the expression (6) is satisfied. In the case of the vibration amplitude change rate A too, a unit similar to that shown in Fig. llB can be used for the purpose.
In lieu of the evaluation of ~A(t) > 0 shown in the expression (6), the absolute value of ~A(t) may be evaluated. For example, a predetermined reference value F may be prepared, and evaluation may be made as to whether the relation ¦QA(t)¦ ~ ~ holds or not. This 1 1556~4 1 latter manner of evaluation is effective for the diagnosis of a symptom of shaft vibration tending to deviate from the estimated value.
In a modification, a specific frequency component fB may be extracted from the shaft vibration signal 101, and the behaviour of a point lying in the safety region may be diagnosed according to a method similar to that described with reference to Fig. 8 For example, a plurality of filters FILTERl to FILTERn as shown in Fig. 7D may be provided to extract an amplitude Afl of frequency fl, amplitude Af2 of frequency f2, and amplitude Afn of frequency fn from the shaft vibra-tion signal 101. In Fig. 7D, Afl to Afn represent the differentiated values of the amplitudes Afl to Afn respectively. In the case of symptom diagnosis on, for example, the frequency f2, the symptom diagnosis is carried out on a set of Af2 and Af2 according to a method similar to that described with reference to Fig. 8. The same applies to the other frequencies. This method is advantageous in that the shaft vibration can be continu-ously monitored even in the accelerating stage of the rotary machine when the specific frequencies are selected in relation to the frequency fR of rotation of the rotary machine. For example, it is convenient to select the frequency f1 to be fl = 2fR (or 3fR), the frequency f2 to be f2 = 1/2-fR or 1/3-fR and so on-In a modification shown in Fig. 7E, a frequencyanalyzer is provided to extract such specific frequencies `::
. ~ ~
:; .
1 ~5~84 1 by digital frequency analysis, and symptom diagnosis is carried out in a manner entirely similar to that described above.
, . - 26 -:
, .
:, ~
: A method as illustrated in Fig. 3A has been proposed so as to diagnose unusual vibration of the rotor shaft 11 of the rotary machine on the basis of the relation between the vibration amplitude A and the rotation speed N of the rotary machine. Referring to Fig. 3A, there are shown an alarm region, a trip region and a safety region related to the rotation speed N
_ 9 _ - ~1556~
1 of the rotary machine. In the alarm region, the relations Al < A < A2, A3 < A < A4 and A5 < A < A6 hold when the rotation speed N lies within the ranges of 0 < N ~ Nl, Nl < N < N2 and N2 ~ N < N3 respectively. In the trip region, the relations A2 ~ A, A4 < A and A5 < A hold ; when the rotation speed N lies within the above ranges respectively. In the safety region, the relations 0 < A < Al, 0 < A < A3 and 0 < A < A5 hold when the rotation speed N lies within the above ranges respectively.
Besides the above method of monitoring the shaft vibration by dividing the rotation speed range into a plurality of ranges as shown in Fig. 3A, there is another method in which the shaft vibration is monitored on the basis of continuous functions fl(N) and f2(N) of the rotation speed N of the rotary machine. In Fig. 3B, the relation fl(N) < A < f2(N) holds in an alarm region, the relation f2(N) < A holds in a trip region, and the relation A < fl(N) holds in a safety reglon. In each of these prior art methods, no monitoring is done on the behaviour of the amplitude of vibration lying within the safety region. The prior art methods are therefore defective in that a predictive diagnosis of a symptom of unusual operation of the rotary machine cannot be ` expected although such a symptom may have already appeared in the safety region.
The present invention contemplates to make an adequate diagnosis of the operating condition of the rotary machine by quickly detecting appearance of a 6~4 1 symptom of unusual operation of the rotary machine in the safety region.
More precisely, the present invention is featured by the fact that the state of vibration of the rotor shaft of the rotary machine is monitored while the amplitude of vibration lies still within the safety region by establishing a safety behavious region within ; the safety region on the basis of the present status of ` the amplitude of vebration and the rate of change of the amplitude of vibration, renewing the sa~ety behaviour region in response to a change of the status of the amplitude of vibration and the rate of change of the vibration amplitude, and detecting appearance of a symptom of unusual operation of the rotary machine when the amplitude of vibration and/or the rate of change of the vibration amplitude exceed the individual values of the safety behaviour region.
Describing in further detail, the safe~y region is commonly determined on the basis of the relation between the vibration amplitude A and the rate of change of the vibration amplitude A in a manner as shown in Fig. 4. It will be seen in Fig. 4 that the relations A ~ Al and A < Al hold in the safety region. Consider now a point Pl in the safety region. There are margins of Pl x in the vibration amplitude change rate A and Pl y in the vibration amplitude A until the point Pl moves out into the alarm region from the safety region. On the other hand, in the case of another point P2 lying `` 11556~4 1 also within the safety region, it has a margin of P2 x in the vibration amplitude change rate A and a margin of P2 y in the vibration amplitude A. Similarly, in the case of still another point P3 lying within the safety region, it has a margin of P3 x in the vibration amplitude change rate A and a margin of P3 y in the vibration amplitude A. It will be seen that the margin P2 y is larger than the margin P2 x in the case of the point P2, while the margin P3 x is larger than the ~;10 margin P3 y in the case of the point P3. Thus, in the case of the point P3, it has been considered that an abrupt change in the vibration amplitude change rate A
will not move the point P3 out of the safety region and the point P3 will still remain within the safety region.
Similarly, in the case of the point P2, it has been ;considered that an abrupt change in the vibration amplitude A will not move the point P2 out of the safety region and the point P2 will still remain within the `-safety region. There have thus been no means for recognizing such a status, and these points have been judged to remain within the safety region in spite of a possible abrupt change in the status. It has therefore been impossible to recognize future behaviour of these points lying within the safety region:
The present invention contemplates to detect a sympton of unusual operation of the rotary machine while the points lie still within the safety region.
Fig. 5 shows schematically the basic concept of the .' `" .
... .
1 ~556~
., 1 present invention for detecting a symptom of unusual - operation of the rotary machine by recognizing future behaviour of the points Pl, P2 and P3. Referring to , Fig. 5, symptom diagnostic regions for the individual points Pl, P2 and P3 are established within the safety region, and appearance of a symptom of unusual operation ` of the rotary machine is predicted or estimated when any one of the points Pl, P2 and P3 moves out of its symptom diagnostic region. In Fig. 5, these regions are shown concentric with respect to the individual points Pl, 2 and P3.
Fig. 6 is a block diagram showing the general structure of a shaft vi~ration monitoring system includ-ing the parts emobying the method according to the present invention. Referring to Fig. 6, a detector circuit 20 corresponds to that shown in Fig. 2, and a shaft vibration signal 101 is applied thereto from the vibration transducer 12 shown in Fig. lB. A pulse generator 23 corresponds to that shown in Fig. lC. A
function generator 21 generates an output signal Ar indicative of a function fl(N) of the rotation speed N
of the rotary machine in response to the application of the pulse signal from the rotation speed-responsive pulse generator. A differentiation (dA/dt) circuit 22 corresponding to that shown in Fig. 2 generates an output signal indicative of the vibration amplitude change rate A. A first level comparator 31 compares the level of the output signal of the detector circuit 20 -` 11S56~
1 indicative of the detected vibration amplitude A with that of the output signal Ar of the function generator 21 and generates an alarm signal or a trip signal 33 when the relation A ~ Ar holds. A second level comparator 5 16 compares the level of the output signal of the dif-ferentiator 22 indicative of the detected vibration amplitude change rate A with a predetermined setting Ar of the vibration amplitude change rate A and generates an alarm signal 18 when the relation A ~ Ar holds.
s 10 Thus, both of the vibration amplitude A and its change rate A are monitored at the same time. Such an arrange-, ment is, however, still insufficient in that nothing is done until the level of the setting Ar or Ar is reached.
A symptom diagnostic unit 30 ls the charac-15 teristic part of the present invention. Fig. 7A shows the detailed structure of one form of the symptom diagnostic unit 30, and Fig. 8 illustrates the basic principle of symptom diagnosis according to the present invention.
Suppose now that Po(Ao, Ao) is the monitored point determined from the values of A and A lying within the safety region. Suppose then that allowable changes of A and A at the point PO sub~ected to the symptom diagnosis are set at ~AL and ~AL. The symptom diagnostic region S at that time is expressed by the following equation (1):
1 1556~
(A - Ao)2 (A - A )2 ,~ 2 2 = 1 ............................ (1) ~A ~A
L L
1 The symptom diagnostic region S is circular as shown in Fig. 8 when ~AL and ~AL are selected to be ~AL = QAL.
Since ~AL and ~AL represent increments of A and A
respectively during the symptom diagnostic period ~t, they can be expressed by the differences {A (t + ~t) -A (t)} and {A (t + ~t) - A (t)} resp~ctively. When the : point PO moves to the point Pl lying also within the symptom diagnostic region S at the time (t + ~t), that is, when the following expression Pl {A (t + ~t), A (t + ~t)} ~ S ' (2) ' holds, a new symptom diagnostic region S is established by selecting this point Pl as a new origion. If the relation Pl ~ S holds, this proves appearance of a symptom of unusual operation of the rotary machine, and an unusual symptom signal is generated. In this manner, symptom diagnosis can be carried out even when the point P lies still within the safety region.
The detailed structure of the symptom diag-nostic unit 30 according to the present invention will now be described with reference to Fig. 7A. The symptom diagnostic period Tsy is provided by a symptom diagnostic - timing signal ~fsy) generator 50. This symptom ~ 15 -1 1556~4 1 diagnostic period T provided by the symptom diagnostic timing signal generator 50 is selected independently of, for example, the sampling period for digital processing of the shaft vibration signal 101. The diagnostic timing is determined in relation to the symptom diagnostic region S (or ~AL and QAL) described above. When the symptom diagnostic period Tsy is excessively long, the significance of symptom diagnosis will be lost, while when it is excessively short, true symptom diagnosis may not be attained. Therefore, Tsy (or fsy) shown in Fig.
9A is determined depending on whether the symptom diagnosis is directed to the operating characteristic of the rotary machine under consideration or to the operat-ing condition under acceleration of the rotary machine or to the steady operating condition of the rotary machine.
The data receiving pulse fsy shown in Fig. 9A
is generated from the symptom diagnostic timing signal generator 50 in each symptom diagnostic period Tsy to permit passage of data A and A through respective gate circuits 52 and 62. The data A and A are then applied to respective registers (I) 54 and (I) 64 in timed relation with a timing pulse Pl shown in Fig. 9B, and the next data A and A are applied to respective registers (II) 56 and (II) 66 in timed relation with another timing pulse P2 shown in Fig. 9C. Fig. 9D shows the ` timing of renewal of the data A and A registered in the respective registers (I) 54, 64 and (II) 56, 66. The :
. -`- 11556~4 ... .
1 term "renewal" indicates that the data A and A are sequentially alternately registered in the respective registers (I) 54, 64 and (II) 56, 66 so that newest ` data can be used for the purpose of symptom diagnosis.
Fig. 9E shows how the symptom is diagnosed using the data A and A registered in the respective registors (I) and (II), and it will be seen that the symptom diagnosis is repeated as shown by the steps SYMPl to SYMPn. For example, diagnostic calculation using the data A and A
registered in the respective registers (I) and (II) is executed in the step SYMPl, and in the next step SYMP2, diagnostic calculation is executed using the data registered in the registers (II) and used already in the step SYMPl together with the new data registered now in the registers (I).
Referring to Fig. 7A again, the data A regis-tered at time t in the register (I) 54 and the data A
registered at time (t + ~t) in the register (II) 56 are applied to a difference calculating circuit (I) 58 which calculates the difference ~A between the inputs, and the calculated difference ~A is applied from the calculat-ing circuit (I) 58 to a deviation calculating circuit (I) 60 which calculates a deviation of ~A from ~AL.
The result of calculation is applied from the deviation calculating circuit (I) 60 to a selective output circuit 75. Similarly, the data A registered at time t in the register (I) 64 and the data A registered at time (t + ~t) in the register (II) 66 are applied to a 1 ~556 :' 1 difference calculating circuit tII~ 68 which calculates ; the difference ~A between the inputs, and the calculated difference ~A is applied from the calculating circuit (II) 68 to a deviation calculating circuit (II) 70 which calculates a deviation of ~A from ~AL. The result of calculation is also applied from the deviation calculat-ing circuit (II) 70 to the selective output circuit 75.
Therefore, the term "diagnostic calculation"
referred to above is used to include the difference calculation executed in the difference calculating clrcuits (I) 58 and (II) 68, and the deviation calcula-tion executed in the deviation calculating circuits (I) 6C and (II) 70 which apply the results of calculation to the selective output circuit 75. When, for example, the difference between the value of A detected at time (t + ~t) and that of A detected at time t does not exceed the value of ~AL, that is, when A(t + ~t) - A(t) ~ ~AL ------------- (3), a symptom signal al as shown in Fig. 9F appears from the selective output circuit 75. When, similarly, the . 20 difference between the value of A detected at time (t + ~t) and that of A detected at time t exceeds the value of ~AL, that is, when A(t + ~t) - A(t) ~ ~AL (4)' l a symptom signal al as also shown in Fig. 9F appears from the selective output circuit 75. It will be seen in Fig. 9F that an output signal from the selective output circuit 75 is shown by the solid waveform when the difference ~A or ~A above described exceeds the ; setting defining the region S, and another output signal is shown by the dotted waveform when the difference ~A
or ~A does not exceed the setting defining the region S.
Thus, the symptom signals al, a3, an_l, an_l and an indicate that the setting is exceeded. These symptom signals are sequentially applied from the selective output circuit 75 to a memory 80 and to an accumulative counter 82 shown in Fig. 7A. These data are sequentially stored in the memory 80 to be utilized for the analysis of the operating condition of the rotary machine.
The accumulative counter 82 counts the symptom signals shown in Fig. 9F, and, when the count attains a predetermined setting Csy, it generates an alarm signal M. Fig. 9G shows the progressive increase of the count of the counter 82 until the count attains the setting Csy at time ta at which the alarm signal M shown in Fig. 9H is generated. The counter 82 is reset at time tcr after counting the pulses for a predetermined period of time and is then set to start its counting operation again.
The values of ~AL and ~AL defining the symptom diagnostic region S may be fixed. However, it is common practice that these values are suitably adjustable by .
: ` 11S56~4 1 a symptom diagnostic region setting circuit 90 shown in Fig. 7A. This symptom diagnostic region setting circuit 90 may be manually controlled for the purpose of manual setting of the values of ~AL and ~AL or an external setting signal Ex may be applied to this circuit 90 for suitably externally setting the values of ~AL and ~AL.
Although the counter 82 is adapted to make an accumulative counting operation as shown in Fig. 9G, the symptom signal a or a applied to the counter 82 may be suitably weighted, as, for example, shown in Fig. 7B. Referring to Fig. 7B, a weighting element 84 is disposed in a signal path extending between the selective output circuit 75 and the counter 82 to multiply the signal a or a by a suitable weight W. For this purpose, a coefficient unit of simple structure can be used. It is a matter of choice to multiply the signal a by the weight W or to multiply the signal a by the weight W.
In the deviation calculating circuits (I) 60 and (II) 70~ deviations of ~A from ~AL and ~A from ~AL
are calculated. However, the ratios therebetween may be calculated by a circuit as, for example, shown in Fig.
7C. Referring to Fig. 7C, each of the circuits 60 and 70 is modified to include a ratio calculating circuit 86 and a comparator 88. The ratio calculating circuits 86 calculate the ratios ~A/~AL and ~A/~AL respectively, and each of the comparators 88 compares the result of calculation by the associated ratio calculating circuit 1 1556~4 1 86 with unity Therefore, when the result of comparison proves that ~A/aAL ~ 1.0 or ~A~AL ~ 1.0, a symptom signal a or a as shown in Fig. 9F is applied to the counter 82.
In the form shown in Fig. 8, the symptom diagnostic region S is defined to be a circle depicted around a point Po(Ao, Ao). However, the shape of the symptom diagnostic region S is in no way limited to the circle shown in Fig. 8. Thus, the relation between aAL
and aAL may be ¦QAL¦ ~ ¦aAL¦. For example, the shape of the symptom diagnostic region S may be elliptical as shown in Fig. lOA. In such a case, lt is effective to determine the shape of the region S in relation to the direction of progressive movement of the point P. The ; 15 shape of the symptom diagnostic region S may be sectoral as shown in Fig. lOB. In such a case, judgment may be made as to whether Pl ~ S, and a symptom signal may be generated when Pl ~ S.
Fig. lOC shows that the progressive movement of point P from, for example, PO to P5 is traced, and the safety region is divided into, for-example, a plurality of small symtom diagnostic regions Sl to S12.
When, for example, the result of symptom diagnosis at time intervals of the symptom diagnostic period Tsy proves that the point P has progressively moved from PO
1' P2, P3 and P4 as shown in Fig. lOC, judgment is made as to how many such small symptom diagnostic regions have been passed until finally the .
~,~
' ` 11556~4 1 point P5 is reached. In the case of Fig. lOC, the number of the small symptom diagnostic regions through which the point P has passed is five. In the method of symptom diagnosis shown in Fig. lOC, the presence of a symptom of unusual operation of the rotary machine is diagnosed when the number of the small symptom diagnostic regions through which the point P has passed is larger than a predetermined setting. When such a number is smaller than the predetermined setting, the operating condition of the rotary machine is relatively stable, and the result of symptom diagnosis proves that there is no symptom of unusual operation of the rotary machine.
Figs. llA and llB show another embodiment of the method according to the present invention. Referring to Fig. llA, a vibration amplitude value A(t) at time t is predicted or estimated on the basis of similar values A(t - ~t) and A(t - 2~t), and the deviation QA~t) of A(t) from A(t) is monitored. The following equation holds .. , ~A(t) = A(t) - A(t) ........................... C5) = A(t) - {A(t - ~) + A(t - ~t) - A(t - 2~t)}
= A(t) - 2A(t - ~t) + A(t - 2~t) And, the presence of a symtom of unusual operation of the rotary machine is diagnosed when the following .
` 11556~4 1 relation holds:
~A(t) > 0 ...................... t6) According to this method, the vibration amplitude value Att) at time t is estimated utilizing the data obtained at time (t - ~t) and at time (t - 2~t), and the presence of a symptom of unusual operation of the rotary machine is diagnosed when ~A(t) is equal to or larger than 0. This method is thus effective for the diagnosis of the tendency of changing vibration.
In lieu of the method just described, a change of the vibration amplitude difference may be monitored.
For example, the infinitesimal change ~A'(t) of the vibration amplitude difference in Fig. llA is given by ~A'(t) = {A(t) - A(t -Qt)} - {A(t - Qt) - A(t - 2~t)}
= A(t) - 2A(t - ~t) + A(t - 2~t) ...... (7) Therefore, ~A'(t) can be estimated by linear approxima-tion, and this manner of symptom diagnosis is as effective as that described with reference to Fig. llA. The principle of symptom diagnosis above described applies also to A. Herein, the method of symptom diagnosis on the detected vibration amplitude A will be described with reference to Fig. llB, by way of example. Referring to Fig- llB, a predictive symptom diagnostic unit 100 is ! connected at its inputs to the registers (I) 64 and 1 1 556~4 1 (II) 66 and at its output to the selective output circuit 75 and includes a predictive information register 102 which stores a plurality of data required for the predictive symptom diagnosis. For the purpose of predictive symptom diagnosis of the vibration amplitude A described with reference to Fig. llA, the register 102 may have a capacity of registering at least three data since A(t) is estimated on the basis of the data A(t - ~t) and A(t - 2~t). The contents of the register 102 are sequentially renewed by the data sampled at time intervals of the symptom diagnostic period Tsy. A
predictive calculating circuit 104 calculates the estimated vibration amplitude value A(t) at time t on the basis of the data A(t - ~t) and A(t - 2~t) registered in the register 102. A comparator 106 executes the calculation of QA(t) according to, for example, the equation (5), and an evaluating circuit 108 evaluates whether the relation ~A(t) > 0 shown in the expression (6) holds or not. The presence of a symptom of unusual operation of the rotary machine is diagnosed ` when the expression (6) is satisfied. In the case of the vibration amplitude change rate A too, a unit similar to that shown in Fig. llB can be used for the purpose.
In lieu of the evaluation of ~A(t) > 0 shown in the expression (6), the absolute value of ~A(t) may be evaluated. For example, a predetermined reference value F may be prepared, and evaluation may be made as to whether the relation ¦QA(t)¦ ~ ~ holds or not. This 1 1556~4 1 latter manner of evaluation is effective for the diagnosis of a symptom of shaft vibration tending to deviate from the estimated value.
In a modification, a specific frequency component fB may be extracted from the shaft vibration signal 101, and the behaviour of a point lying in the safety region may be diagnosed according to a method similar to that described with reference to Fig. 8 For example, a plurality of filters FILTERl to FILTERn as shown in Fig. 7D may be provided to extract an amplitude Afl of frequency fl, amplitude Af2 of frequency f2, and amplitude Afn of frequency fn from the shaft vibra-tion signal 101. In Fig. 7D, Afl to Afn represent the differentiated values of the amplitudes Afl to Afn respectively. In the case of symptom diagnosis on, for example, the frequency f2, the symptom diagnosis is carried out on a set of Af2 and Af2 according to a method similar to that described with reference to Fig. 8. The same applies to the other frequencies. This method is advantageous in that the shaft vibration can be continu-ously monitored even in the accelerating stage of the rotary machine when the specific frequencies are selected in relation to the frequency fR of rotation of the rotary machine. For example, it is convenient to select the frequency f1 to be fl = 2fR (or 3fR), the frequency f2 to be f2 = 1/2-fR or 1/3-fR and so on-In a modification shown in Fig. 7E, a frequencyanalyzer is provided to extract such specific frequencies `::
. ~ ~
:; .
1 ~5~84 1 by digital frequency analysis, and symptom diagnosis is carried out in a manner entirely similar to that described above.
, . - 26 -:
, .
:, ~
Claims (8)
1. In a method of diagnosing an unusual symptom during a region of a safe operation in which an amplitude value of a shaft vibration signal of a rotary machine is smaller than a predetermined value, and a change ratio of the shaft vibration signals is smaller than a predetermined value, a method of diagnosing an unusual symptom by monitoring the shaft vibration of the rotary machine characterized by the steps of:
detecting the amplitude value of the shaft vibration signal and the change ratio of the shaft vibration signals, at a predetermined diagnosing period, setting and memorizing an absolute value of a predetermined change from the amplitude value and the change ratio of said shaft vibration signals respectively, which are detected at the nth diagnosing period, for the purpose of using said absolute value as a reference value for deciding an unusual symptom at the (n+1)th diagnosing period, calculating the absolute value of deviations between the amplitude value and the change ratio thereof of the shaft vibration signals at the (n+1) diagnosing period, and the amplitude value and the change ratio thereof of the shaft vibration signals at the nth diagnosing period respectively, and determining the presence of a symptom of unusual operation of said rotary machine when at least one of the calculated variations exceeds the set and memorized value of the reference value.
detecting the amplitude value of the shaft vibration signal and the change ratio of the shaft vibration signals, at a predetermined diagnosing period, setting and memorizing an absolute value of a predetermined change from the amplitude value and the change ratio of said shaft vibration signals respectively, which are detected at the nth diagnosing period, for the purpose of using said absolute value as a reference value for deciding an unusual symptom at the (n+1)th diagnosing period, calculating the absolute value of deviations between the amplitude value and the change ratio thereof of the shaft vibration signals at the (n+1) diagnosing period, and the amplitude value and the change ratio thereof of the shaft vibration signals at the nth diagnosing period respectively, and determining the presence of a symptom of unusual operation of said rotary machine when at least one of the calculated variations exceeds the set and memorized value of the reference value.
2. A method of diagnosing an unusual symptom as claimed in claim 1, characterized by the steps of:
setting a safety operation region of said rotary machine on a two-dimensional plane defining the amplitude value and the change rate of the amplitude value of the detected shaft vibration signals;
setting and memorizing the region including the detected value of said shaft vibration signals at the nth diagnosing period for the purpose of using it as a reference value for deciding an unusual symptom at the (n+1)th diagnosing period, and determining the presence of a symptom of unusual operation of said rotary machine when the shaft vibration signal of said rotary machine detected at the (n+1)th unusual symptom diagnosing period is fallen outside said unusual symptom diagnosis determining region.
setting a safety operation region of said rotary machine on a two-dimensional plane defining the amplitude value and the change rate of the amplitude value of the detected shaft vibration signals;
setting and memorizing the region including the detected value of said shaft vibration signals at the nth diagnosing period for the purpose of using it as a reference value for deciding an unusual symptom at the (n+1)th diagnosing period, and determining the presence of a symptom of unusual operation of said rotary machine when the shaft vibration signal of said rotary machine detected at the (n+1)th unusual symptom diagnosing period is fallen outside said unusual symptom diagnosis determining region.
3. A method of diagnosing an unusual symptom as claimed in claim 1, charaeterized by the steps of:
detecting a specific frequency component of said detected shaft vibration signal; and determining the presence of a symptom of unusual operation of said rotary machine when said specific frequency component exceeds a predetermined value of change.
detecting a specific frequency component of said detected shaft vibration signal; and determining the presence of a symptom of unusual operation of said rotary machine when said specific frequency component exceeds a predetermined value of change.
4. A method of diagnosing an unusual symptom as claimed in claim 3, characterized in that said specific frequency component has a predetermined relation with the rotation frequency of the rotary machine, and its behaviour is continuously monitored for the diagnosis of a symptom of unusual operation of the rotary machine.
5. A method of diagnosing an unusual symptom as claimed in claim 2, characterized in that said usual operation region is divided into a plurality of small symptom diagnostic regions, and a symptom of unusual operation of said rotary machine is diagnosed on the basis of the number of said small symptom diagnostic regions through which the point representing said detected shaft vibration signal has progressively moved.
6. A method of diagnosing an unusual symptom as claimed in claim 2, characterized in that the number of times the level of said detected shaft vibration signal deviates from that of the predetermined symptom diagnostic regions established at time intervals of said symptom diagnostic periods is counted by a counter and the presence of a symptom of unusual operation of the rotary machine is detected when the count of said counter exceeds a predetermined number.
7. A method of diagnosing an unusual symptom as claimed in claim 2, characterized in that when the level of said detected shaft vibration signal deviates from that of the predetermined symptom diagnostic regions established at time intervals of said symptom diagnostic period due to level variations, one of said vibration amplitude and said vibration amplitude change rate is multiplied by a weight, and the number of deviations is counted by a counter.
8. In an apparatus for diagnosing an unusual symptom during an usual operation of a rotary machine by detecting and monitoring shaft vibration signals due to the rotation of said rotary machine, an apparatus for diagnosing an unusual symptom characterized by:
timing signal generating means for generating timing signals for diagnosing the unusual symptom during said usual operation of said rotary machine;
first and second memory means for memorizing the amplitude signals of said shaft vibration signals in response to the timing signal at the nth and (n+1)th unusual symptom diagnosing periods;
third and fourth memory means for memorizing the change rate of the amplitude of said shaft vibration signals in response to the timing signal at the nth and (n+1)th unusual symptom diagnosing periods;
determination-reference memory means for setting and memorizing the change of the amplitude value and the change rate of the amplitude value of said shaft vibration signals which are detected as a determination reference for the unusual symptom diagnosis, at the (n+1)th unusual symptom diagnosing period, in the nth 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 of said first calculation means with the change of said amplitude value memorized in said determination-reference memory means; and second comparing means for comparing the calculation results of said second calculation means with the change of said change rate of the amplitude value memorized in said determination-reference memory means;
wherein the presence of a symptom of unusual operation of said rotary machine is detected when at least either one of the outputs of said first and second comparing means exceeds the change set in said determination-reference memory means.
timing signal generating means for generating timing signals for diagnosing the unusual symptom during said usual operation of said rotary machine;
first and second memory means for memorizing the amplitude signals of said shaft vibration signals in response to the timing signal at the nth and (n+1)th unusual symptom diagnosing periods;
third and fourth memory means for memorizing the change rate of the amplitude of said shaft vibration signals in response to the timing signal at the nth and (n+1)th unusual symptom diagnosing periods;
determination-reference memory means for setting and memorizing the change of the amplitude value and the change rate of the amplitude value of said shaft vibration signals which are detected as a determination reference for the unusual symptom diagnosis, at the (n+1)th unusual symptom diagnosing period, in the nth 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 of said first calculation means with the change of said amplitude value memorized in said determination-reference memory means; and second comparing means for comparing the calculation results of said second calculation means with the change of said change rate of the amplitude value memorized in said determination-reference memory means;
wherein the presence of a symptom of unusual operation of said rotary machine is detected when at least either one of the outputs of said first and second comparing means exceeds the change set in said determination-reference memory means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4032280A JPS56137222A (en) | 1980-03-31 | 1980-03-31 | Axial vibration monitoring method for rotating machine |
| JP40322/80 | 1980-03-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1155684A true CA1155684A (en) | 1983-10-25 |
Family
ID=12577365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000374143A Expired CA1155684A (en) | 1980-03-31 | 1981-03-30 | Method of sympton diagnosis by monitoring vibration of shaft of rotary machine |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4437163A (en) |
| JP (1) | JPS56137222A (en) |
| AU (1) | AU530546B2 (en) |
| CA (1) | CA1155684A (en) |
| DE (1) | DE3112567C2 (en) |
Families Citing this family (51)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58100717A (en) * | 1981-12-11 | 1983-06-15 | Komatsu Ltd | Abnormality detector |
| FR2539874B1 (en) * | 1983-01-20 | 1985-07-05 | Alsthom Atlantique | MONITORING SYSTEM FOR TORSIONAL DAMAGE OF A SHAFT LINE COMPOSED OF A DRIVING MACHINE AND A DRIVEN MACHINE |
| US4559600A (en) * | 1983-02-28 | 1985-12-17 | Battelle Memorial Institute | Monitoring machine tool conditions by measuring a force component and a vibration component at a fundamental natural frequency |
| JPS59174732A (en) * | 1983-03-24 | 1984-10-03 | Mitsubishi Electric Corp | Apparatus for judging abnormality of gear unit |
| JPS59178357A (en) * | 1983-03-29 | 1984-10-09 | Mitsubishi Electric Corp | Detecting device of extraordinary noise of gear |
| JPS6018729A (en) * | 1983-07-11 | 1985-01-30 | Mitsubishi Electric Corp | Vibration monitoring device |
| US4704693A (en) * | 1985-06-28 | 1987-11-03 | General Electric Company | Acoustic tool touch detector with minimized detection delay |
| US4782452A (en) * | 1986-08-25 | 1988-11-01 | General Electric Company | Acoustic detection of milling tool touch to a workpiece |
| DE3785907T2 (en) * | 1986-09-26 | 1993-11-11 | Sumitomo Electric Industries | Vibration removal system when switched on. |
| DE3705268A1 (en) * | 1987-02-19 | 1988-09-01 | Industrieanlagen Betriebsges | RESONANCE-BASED TESTING MACHINE FOR VEHICLE STABILIZERS |
| DE3734487A1 (en) * | 1987-10-12 | 1989-04-20 | Grs Ges Reaktorsicherheit | Method for monitoring the reliable mode of operation and for the early detection of damage in complicated technical systems |
| US4853680A (en) * | 1988-01-12 | 1989-08-01 | General Electric Company | Groove cutting tool break event detecting method and system |
| US5251151A (en) * | 1988-05-27 | 1993-10-05 | Research Foundation Of State Univ. Of N.Y. | Method and apparatus for diagnosing the state of a machine |
| US4977510A (en) * | 1989-07-21 | 1990-12-11 | 501 Balance Dynamics Corporation | Computerized control system and method for balancers |
| DE4406723B4 (en) * | 1993-02-27 | 2005-02-03 | Dr. Boetius + Partner Informationssysteme Gmbh | Method for monitoring the operating state of a machine or plant |
| US5544073A (en) * | 1994-06-02 | 1996-08-06 | Computational Systems, Inc. | Rotor balancing calculator |
| US5610339A (en) * | 1994-10-20 | 1997-03-11 | Ingersoll-Rand Company | Method for collecting machine vibration data |
| US5602757A (en) * | 1994-10-20 | 1997-02-11 | Ingersoll-Rand Company | Vibration monitoring system |
| IT1284328B1 (en) * | 1996-01-19 | 1998-05-18 | Fiat Ricerche | METHOD AND UNIT OF DIAGNOSIS OF FAILURES OF INJECTORS OF HIGH PRESSURE INJECTION SYSTEMS FOR INTERNAL COMBUSTION ENGINES |
| DE19702234A1 (en) * | 1997-01-23 | 1998-08-06 | Acida Gmbh Aachener Ct Fuer In | Method of monitoring and quality control of machine parts |
| US6507790B1 (en) | 1998-07-15 | 2003-01-14 | Horton, Inc. | Acoustic monitor |
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| ATE315219T1 (en) * | 1999-05-19 | 2006-02-15 | Vibro Meter Ag | METHOD AND ARRANGEMENT FOR COMBINED VIBRATION MEASUREMENT |
| US6714880B2 (en) * | 2002-05-13 | 2004-03-30 | Entek Ird International Corporation | Multi-alarm monitoring and protection system |
| US6763312B1 (en) | 2003-01-11 | 2004-07-13 | Dynamic Measurement Consultants, Llc | Multiple discriminate analysis and data integration of vibration in rotation machinery |
| WO2006067398A1 (en) * | 2004-12-20 | 2006-06-29 | Renishaw Plc | Machine and control system |
| US7606673B2 (en) * | 2006-05-01 | 2009-10-20 | Dynamic Measurement Consultants, Llc | Rotating bearing analysis and monitoring system |
| FR2937079B1 (en) * | 2008-10-10 | 2011-08-26 | Snecma | METHOD AND SYSTEM FOR MONITORING A TURBOREACTOR |
| DE102009028364A1 (en) * | 2009-08-10 | 2011-02-17 | Zf Friedrichshafen Ag | Method for early damage detection in a motor vehicle transmission |
| US8222760B2 (en) * | 2010-06-29 | 2012-07-17 | General Electric Company | Method for controlling a proximity sensor of a wind turbine |
| DK2581724T3 (en) * | 2011-10-13 | 2020-06-29 | Moventas Gears Oy | Method and system for condition monitoring of gearboxes |
| EP2634898A1 (en) * | 2012-03-01 | 2013-09-04 | Siemens Aktiengesellschaft | Method for operating an electric machine |
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| US10040577B2 (en) | 2016-02-12 | 2018-08-07 | United Technologies Corporation | Modified start sequence of a gas turbine engine |
| US10443507B2 (en) | 2016-02-12 | 2019-10-15 | United Technologies Corporation | Gas turbine engine bowed rotor avoidance system |
| US10358936B2 (en) | 2016-07-05 | 2019-07-23 | United Technologies Corporation | Bowed rotor sensor system |
| JP6595416B2 (en) * | 2016-08-09 | 2019-10-23 | ファナック株式会社 | Servo control device, spindle failure detection method using the servo control device, and computer program |
| CN109084882B (en) * | 2018-09-30 | 2023-09-26 | 华南理工大学 | Rotary disc vibration detection control device and method |
| JP7260410B2 (en) * | 2019-06-18 | 2023-04-18 | 日立Ｇｅニュークリア・エナジー株式会社 | Abnormal Diagnosis Method for Rotating Machinery |
-
1980
- 1980-03-31 JP JP4032280A patent/JPS56137222A/en active Pending
-
1981
- 1981-03-30 CA CA000374143A patent/CA1155684A/en not_active Expired
- 1981-03-30 DE DE3112567A patent/DE3112567C2/en not_active Expired
- 1981-03-30 US US06/248,846 patent/US4437163A/en not_active Expired - Fee Related
- 1981-03-31 AU AU68931/81A patent/AU530546B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| DE3112567A1 (en) | 1982-04-08 |
| DE3112567C2 (en) | 1984-08-30 |
| AU530546B2 (en) | 1983-07-21 |
| JPS56137222A (en) | 1981-10-27 |
| AU6893181A (en) | 1981-10-08 |
| US4437163A (en) | 1984-03-13 |
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