JPH05322641A - Misalignment detector for rotary machine - Google Patents

Abstract

PURPOSE:To detect misalignment of various rotary machines accurately by a constitution wherein a comparing means compares vibration level at each frequency, in order, with a predetermined multiple of an overall value. CONSTITUTION:Vibration of a rotary machine 1 is detected through a vibration detecting means 2 which then produces a vibration displacement waveform signal or a vibration speed waveform signal. An FFT processing means 5 performs FFT analysis on a given waveform signal. A first comparing means 6 compares the vibration level Afo at basic frequency fo of the rotary machine with a value equal to one third of an overall value OA. A second comparing means 62 compares the vibration level A2fo at a frequency two times of the basic frequency fo with the value equal to one third of the overall value OA. A third comparing means 63 compares the vibration level Afo at the basic frequency fo with a value equal to one sixth of overall value OA and delivers a signal representing detection of misalignment to a display means 7 if the vibration level Afo at the basic frequency fo is higher than one sixth of the overall value OA.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a misalignment phenomenon detecting device for a rotating device for detecting misalignment which is one of abnormal phenomena of a rotating device such as a pump.

[0002]

2. Description of the Related Art In recent years, most plants used in the fields of industry and chemistry are automated by a process control system using a computer, and a human (operator) is in a central control room. It has a system that focuses on safety management and equipment management.

By the way, in such a plant,
In many cases, the cause of the plant abnormality is caused by the abnormality of the equipment, and if the abnormality of the plant equipment can be detected (diagnosed) in advance before the occurrence of the plant abnormality, take appropriate measures in advance. As a result, it is possible to maintain high reliability of the plant and reduce maintenance costs.

Various types of rotating equipment are used in the plant. One of the causes of failure is due to the misalignment phenomenon. Therefore, if the misalignment phenomenon of various rotating devices can be accurately detected, the occurrence of plant abnormality can be reduced.

[0005]

However, conventionally, it has not been possible to accurately detect the occurrence and limitation of the misalignment phenomenon, which is one of the causes of abnormality of rotating equipment. The present invention has been made in view of the above circumstances, and a misalignment phenomenon detection device for a rotary device that can accurately detect a misalignment phenomenon that causes an abnormality in the rotary device and improve the reliability of the plant. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION The present invention to achieve such an object is to provide a vibration detecting means for detecting a signal relating to a vibration displacement of a rotating machine or a signal relating to a vibration velocity, and a signal from the vibration detecting means. The FFT processing means for performing frequency analysis, the vibration level value (Afo) of the fundamental rotation frequency (fo) of the rotating device obtained from the FFT processing means, and the value 1/3 times the overall value (OA) The vibration level value (Afo) of the rotation fundamental frequency (fo) of the rotating device in the first comparison means for performing comparison and the first comparison means is 1/3 times the overall value (OA) If it is smaller, the vibration level value (A2fo) at a frequency twice the fundamental rotation frequency (fo) and 1 / of the overall value (OA)
The vibration level value (A2fo) at the frequency twice as high as the fundamental rotation frequency (fo) in the second comparison means for making a comparison with the tripled value is the overall value (O
If it is larger than 1/3 times the value of A), the vibration level value (Afo) of the rotating fundamental frequency (fo) of the rotating device is compared with the value of 1/6 times the overall value (OA). , The vibration level value (Af) of the rotation fundamental frequency (fo) of the rotating device
o) is larger than a value which is 1/6 times the overall value (OA), a misalignment phenomenon detection of a rotating machine is provided, which comprises a third comparing means for outputting a signal indicating the detection of misalignment phenomenon. It is a device.

[0007]

The FFT processing means inputs the vibration displacement signal or the vibration velocity signal from the rotating device, analyzes the frequency, and outputs the spectrum value and the overall value in the predetermined frequency range. The first to third comparing means sequentially compare the vibration level value of each frequency with a predetermined multiple value of the overall value.

Then, in the third comparing means, the vibration level value (Afo) of the rotation fundamental frequency (fo) of the rotating device.
Is larger than a value that is 1/6 times the overall value (OA), a detection signal is output because the misalignment phenomenon has occurred.

[0009]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration block diagram showing an embodiment of the present invention. In the figure, reference numeral 1 is a rotary device such as a pump to be diagnosed, 2 is a vibration detecting means (sensor) for detecting a signal relating to the vibration of the rotary device 1, and the vibration signal is picked up by a piezoelectric element, for example. Alternatively, a device that uses an optical signal for detection is used. Reference numeral 3 is a means for obtaining a vibration displacement waveform using a signal from the vibration detecting means 2. For example, when a vibration acceleration signal is output from the vibration detecting means 2, the signal is double integrated. Different circuits are used. Further, 4 is a means for obtaining a vibration velocity waveform, and if a vibration acceleration signal is output from the vibration detecting means 2, a circuit for integrating the signal is used.

Reference numeral 5 is an FFT processing means for inputting a vibration displacement waveform signal or a vibration velocity waveform signal, analyzing the frequency of the signal, and obtaining a spectrum in a predetermined frequency range and an overall value. Composed using. 6
Reference numeral 1 denotes a first comparison for comparing the vibration level value (Afo) of the basic rotation frequency (fo) of the rotating device 1 obtained from the FFT processing means 5 with a value that is 1/3 times the overall value (OA). Reference numeral 62 is a vibration level value (Afo) of the fundamental rotation frequency (fo) of the rotating device 1 in the first comparison means 61.
Is smaller than 1/3 times the overall value (OA), the vibration level value (A2fo) at the frequency twice the fundamental rotation frequency (fo) and the overall value (OA)
The second comparing means 62 compares the vibration level value (A2fo) at the frequency of twice the fundamental rotation frequency (fo) with the second comparing means 62, When it is larger than 1/3 times the all value (OA), the vibration level value (Af) of the rotating fundamental frequency (fo) of the rotating device
o) and a value that is 1/6 times the overall value (OA) are compared, and the vibration level value (Afo) of the rotating fundamental frequency (fo) of the rotating device is 1/100 of the overall value (OA). The third comparing means outputs a signal indicating the detection of the misalignment phenomenon when the value is larger than 6 times. Reference numeral 7 is a display means for receiving a signal indicating the detection of the misalignment phenomenon output from the third comparison means 63 and displaying a message to that effect, for example, a CRT display is used.

The operation of the apparatus thus configured will be described below. FIG. 2 is a flowchart showing the operation. Vibration or the like generated in the rotating device 1 is detected by the vibration detecting means 2, and this vibration signal is processed to obtain a vibration displacement waveform signal or a vibration velocity waveform signal. These waveform signals are FF
It is given to the T processing means 5. The FFT processing means 5 carries out FFT analysis on the given waveform signal (steps 1 to 3).

FIG. 3 is an empirical data diagram showing the result of waveform analysis performed by the FFT processing means 5. Here, a spectrum (SPECTRUM) is obtained at specific frequencies indicated by numbers (No) 1 to 10, and the amplitude value of the spectrum is the value (unit: μm) shown in the SPECTRUM column. The overall value OA is 4.55.

Such analysis results (data) are
It is given to the third comparing means. The first comparing means 61 is
The vibration level value (Afo) of the fundamental frequency (fo = 29.78 Hz), that is, No. From the data of No. 3, 0.85 μm is obtained as the amplitude level value Afo, and this value is compared with a value (1.52 μm) which is ⅓ times the overall value (OA = 4.55) ( Step 4).

In this example, the comparison result by the first comparing means 61 (the judgment result in step 4) is 1/3 for Afo.
Since it is smaller than the doubled value of OA, the result is NO. The second comparing means 62 receives the judgment result of the first comparing means 61, and subsequently, the vibration level value (A2fo) at the frequency twice the fundamental frequency (fo) and the overall value (OA). ) 1/3
A comparison with the doubled value is performed (step 5). That is, a frequency twice the fundamental frequency (fo) (2fo = 58.75H
It is determined whether the vibration level value (A2fo = 2.45) in z) is larger than a value (1.52) that is 1/3 times the overall value (OA). In this case, the vibration level value (A2fo = 2.45) at the doubled frequency is the overall value (O2
Since it is larger than the value (1.52) which is 1/3 times the value of A), the second
The comparison result of the comparison means 62 is YES.

The third comparing means 63 is the second comparing means 6
After receiving the comparison result in step 2, the vibration level value (Afo) of the basic frequency (fo) is compared with a value that is 1/6 times the overall value (OA) (step 6). In this example, the vibration level value of the fundamental frequency (fo) (Afo = 0.
85) is 1/6 times the overall value (OA) (0.
76), the determination here is YES.

As a result, the third comparing means 63 sends a signal indicating the misalignment detection to the display means 7 and displays the misalignment (for example, displaying a message) (step 7). In addition, in step 5 and step 6, if NO is determined, the process proceeds to step 8 where the relation with the power supply frequency fe is checked to determine whether the cause of the vibration is electromagnetic vibration. ing.

[0017]

As described in detail above, according to the present invention, the misalignment phenomenon of various rotating machines, which has been difficult to detect accurately in the past, can be detected accurately. ..

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation.

FIG. 3 is an empirical data diagram showing a result of waveform analysis performed by an FFT processing means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating device 2 vibration detection means (sensor) 3 means for obtaining a vibration displacement waveform 4 means for obtaining a vibration velocity waveform 5 FFT processing means 61 first comparison means 62 second comparison means 63 third comparison means 7 display means

Claims (1)

[Claims] 1. A vibration detecting means for detecting a signal relating to a vibration displacement of a rotating machine or a signal relating to a vibration velocity, and an FFT for frequency-analyzing a signal from the vibration detecting means.
A first comparison is made between the processing means and the vibration level value (Afo) of the fundamental rotation frequency (fo) of the rotating device obtained from the FFT processing means, and a value that is 1/3 times the overall value (OA). In the first comparison means and the rotation fundamental frequency (f
When the vibration level value (Afo) of o) is smaller than the value of 1/3 times the overall value (OA), the vibration level value (A2f) at the frequency of twice the fundamental rotation frequency (fo).
o) and the second comparison means for comparing the value of 1/3 times the overall value (OA), and the second comparison means vibrates at a frequency twice the fundamental rotation frequency (fo). When the level value (A2fo) is larger than 1/3 times the overall value (OA), the vibration level value (Afo) of the rotating fundamental frequency (fo) of the rotating device
Is compared with a value that is 1/6 times the overall value (OA), and the vibration level value (Afo) of the rotation fundamental frequency (fo) of the rotating device is 1/6 times the overall value (OA). And a third comparing means for outputting a signal indicating the detection of the misalignment phenomenon when the value is larger than the value of.