JPH04232426A - Diagnozing method of rotary machine and apparatus therefor - Google Patents

Abstract

PURPOSE:To diagnoze abnormality while a variable speed rotary machine is operating by setting a standard rotating cycle, and converting to correct a vibrating signal to a time interval of the standard rotating cycle when the measured rotating cycle is different from the standard rotating cycle. CONSTITUTION:A vibrating signal measured by a vibrating sensor 2 is converted and amplified to a voltage signal by a vibrating amplifier 7, and processed by a filter processing part 8. Only an abnormal vibrating signal is extracted. The abnormal vibrating signal is all wave rectified by a rectifying processing part 9, converted to an envelope characteristic signal by an envelope processing part 10, then input to an operating device 6. A rotary signal detected by a revolution sensor 3 in concurrence with tone measurement of the vibration is amplified by a rotating number amplifier 5 and input to the operating device 6. The operating device 6 operates the input vibrating signal and rotary signal, compares the operated value with a preliminarily obtained abnormal vibrating signal. A point of the value of the abnormal vibrating signal which agrees with the operated value of the measured abnormal vibrating signal is specified as an abnormal point.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diagnostic method and apparatus for identifying abnormalities in a rotating machine that operates while changing its rotational speed from time to time.

0002

2. Description of the Related Art In rotating machines, abnormalities such as flaws in bearings, unbalanced rotating bodies, or eccentricity of couplings may occur. . Conventionally, as a technique for diagnosing such an abnormality and identifying the location where the abnormality occurs, a method using vibrations of rotating machinery has been used. An example of a diagnostic method is shown below.

(1) A rotating machine is operated at a constant rotation speed. (2) Next, one or more types of vibrations among vibration displacement, vibration velocity, and vibration acceleration are measured. (3) This vibration signal is subjected to processing such as frequency analysis and autocorrelation analysis to determine the periodicity and period of the vibration signal. (4) Then, the period of the vibration signal is compared with the period of the abnormal vibration signal at each location, which has been determined in advance, and the location where the period of the vibration signal matches is identified as the abnormal location.

[0004]A device for carrying out the above diagnostic method includes:
Based on the following configuration. A vibration sensor that measures vibration, a signal processing means that extracts an abnormal vibration waveform from the measured vibration signal, calculates the period of this abnormal vibration waveform, and then calculates the period of the abnormal vibration waveform and the abnormal vibration of each part that has been input in advance. It consists of an arithmetic unit that compares the period of the signal.

[0005]

[Problem to be Solved by the Invention] However, in the above-mentioned diagnostic method and device, it is necessary to stabilize the rotation speed of the rotating machine before measurement, so when applied to the diagnosis of variable-speed rotating machines, , the machine must be temporarily stopped in order to rotate at a constant speed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a diagnostic method and a diagnostic device that can perform measurements during operation of a variable-speed rotary machine whose rotational speed is changed at any time.

[0007]

[Means for Solving the Problems] In order to achieve the above object, in the method of the present invention, the vibration and rotational speed of a rotating machine are measured in parallel, and abnormal vibration waveforms are detected from the measured vibration signals. The envelope characteristic signal is extracted and converted into an envelope characteristic signal, and the envelope characteristic signal is corrected to the time axis of a predetermined standard rotation period, and the period of this corrected envelope characteristic signal and the variable speed determined in advance are The period of abnormal vibration signals generated in each part when a rotating machine is damaged is compared to identify the abnormal location.

The device of the present invention also includes a vibration sensor for measuring vibration, a rotation sensor for measuring rotational speed, and vibration signal processing means for extracting an abnormal vibration waveform from the measured vibration signal and converting it into an envelope characteristic signal. a conversion means for correcting the envelope characteristic signal to a time interval of a standard rotation period based on the input envelope characteristic signal and the rotation signal measured by the rotation sensor; The apparatus is provided with a comparison calculation means for specifying an abnormal location by comparing and calculating the period of an abnormal vibration signal of each part generated when the variable speed rotary machine is damaged, which has been input in advance.

[0009]

[Function] In processing vibration signals of rotating machines whose rotation speed fluctuates during vibration measurement as described above, a standard rotation period is set, and if the measured rotation period differs from the standard rotation period, the vibration signal is Performs a conversion that stretches or shortens the time interval of the standard rotation period. Therefore, the vibration signal after conversion is apparently the same as the vibration signal of a constant speed rotation system, making it easier to identify the abnormal location.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the configuration of a diagnostic apparatus according to the present invention. This device includes a vibration sensor 2 that measures vibrations of a variable speed rotating machine 1, and a rotation sensor 3 that measures the number of rotations.
, a vibration signal processing means 4 that extracts an abnormal vibration waveform from the measured vibration signal and converts it into an envelope characteristic signal, a rotation amplifier 5 that is a rotation signal processing means, and a rotation signal processing means that calculates the input vibration signal and rotation signal. The main part is constituted by a computing unit 6 that identifies abnormalities in the variable speed rotating machine. 11 is a recording device for the output of the arithmetic unit 6; The vibration signal processing means 4 includes a vibration amplifier 7 that converts the vibration signal measured by the vibration sensor 2 into a voltage signal and amplifies it, a filter processing section 8 that processes the amplified vibration signal and extracts only abnormal vibration signals, and an abnormal vibration signal. It consists of a rectification processing section 9 that performs full-wave rectification of the vibration signal, and an envelope processing section 10 that converts the full-wave rectified abnormal vibration signal into an envelope characteristic signal.

Next, the diagnostic method of the present invention will be explained with reference to FIG. a) Measurement of vibration by vibration sensor 2 and measurement of rotation speed by rotation sensor 3 are performed in parallel. b. The measured vibration signal is converted into a voltage signal and amplified by the vibration amplifier 7. c The amplified vibration signal is processed by the filter processing unit 8 to extract only the abnormal vibration signal. d This abnormal vibration signal is full-wave rectified by the rectification processing section 9. e The signal is then processed by the envelope processing section 10 and converted into an envelope characteristic signal. f This envelope characteristic signal is input to the calculator 6. g The rotation signal measured by the rotation sensor 3 in parallel with the vibration measurement is amplified by the rotation speed amplifier 5 and converted into a pulse signal. h This rotation signal is input to the calculator 6. i The computing unit 6 computes the input vibration signal and rotation signal, and compares the computed value with an abnormal vibration signal obtained in advance and input when each part of the variable speed rotating machine is damaged. Then, a location having an abnormal vibration signal value that matches the calculated value of the measured abnormal vibration signal is identified as an abnormal location.

FIGS. 2(a), (b) and 3(a), (
b) is an explanatory diagram of a vibration signal waveform processing method. In the above-described diagnosis process, waveform processing of vibration signals is performed, and this waveform processing is performed as follows.

FIG. 2A shows the measured rotation signal and vibration signal. (b) shows a state in which the time interval of the rotation signal is measured, and the vibration signal (where ti is the i+1th time interval from i) is subjected to full-wave rectification and then envelope processing.

In the diagram (a) in FIG. 3, the time intervals of the rotation signals are made constant. For example, the time interval ti+1 from i+1 to i+2 is multiplied by t i /t i+1.

The vibration signal is adjusted to the standard rotation period time interval t i of the rotation signal obtained by the above calculation.

[0016] In the diagram (b), autocorrelation of vibration signals with time intervals is performed to determine the period t at which the correlation becomes high.

If the period t of this correlation matches the period (T) of the abnormal vibration signal of the rotating machine, which is separately determined in advance, that location becomes abnormal.

[0018]

[Effects of the Invention] The present invention provides a diagnostic method and device that measures vibration and rotational speed in parallel, processes the vibration signals and rotational signals obtained by this measurement, and then performs calculations to identify an abnormal location. be. Then, when identifying the abnormal location, the measured vibration signal is converted to the time interval of the standard rotation cycle, and the vibration signal is processed so that it appears to be the same as the vibration signal of a constant speed rotation system. Even in variable speed rotating machines where the rotational speed is changed at any time, abnormality diagnosis can be performed while the machine is in operation.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a diagnostic device according to the present invention.

FIG. 2 is an explanatory diagram of a vibration signal waveform processing method.

FIG. 3 is another explanatory diagram of a vibration signal waveform processing method.

[Explanation of symbols]

1 Rotating machinery 2 Vibration sensor 3 Rotation sensor 4 Vibration signal processing means 5 Rotating amplifier 6 Arithmetic unit 7 Vibration amplifier 8 Filter processing section 9 Rectification processing section 10 Envelope processing section

Claims (2)

[Claims] [Claim 1] Vibration and rotation speed of a rotating machine are measured in parallel, an abnormal vibration waveform is extracted from the measured vibration signals and converted into an envelope characteristic signal, and the envelope characteristic signal is determined in advance. Perform a conversion to correct the time axis of the standard rotation period,
The rotating machine is characterized in that the period of the corrected envelope characteristic signal is compared with the period of abnormal vibration signals of various parts that are generated when the variable speed rotating machine is damaged, which has been determined in advance, to identify abnormal locations. diagnostic method. 2. A vibration sensor that measures vibration, a rotation sensor that measures rotation speed, vibration signal processing means that extracts an abnormal vibration waveform from the measured vibration signal and converts it into an envelope characteristic signal, a conversion means for correcting the envelope characteristic signal to a time interval of a standard rotation period based on the envelope characteristic signal and the rotation signal measured by the rotation sensor, and a period of the modified envelope characteristic signal is inputted in advance. A diagnostic device for a rotating machine, comprising a comparison calculation means for identifying an abnormal location by comparing the period of an abnormal vibration signal of each part generated when the variable speed rotating machine is damaged.