JPH0815100A - Vibration diagnosing device with exciting function - Google Patents

Abstract

PURPOSE:To enable a vibration diagnosing device for large-sized rotary machines, such as the turbine, pump, etc., to easily obtain the vibrational characteristic data of the machines at rotating speeds which are higher than the operating rotating speeds of the machines by adding an exciting function to the device. CONSTITUTION:A rotary machine 7 is mounted on a frame 8 and four vibration sensors 5 connected to the main body 4 of a vibration diagnosing device through an amplifier 6 are fitted to the machine 7. An exciter 1 is also fitted the machine 7 and connected to an oscillator 3 connected to the main body 4 through a power amplifier 2. The exciter 1 is excited from the oscillator 3 in accordance with a command from the main body 4 and the sensor 5 detects the vibrational response of the machine 7. Therefore, the vibrational characteristic data of an order higher than the operating rotating speed of the machine 7 can be obtained at arbitrary timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration diagnosing device with a vibrating function, which is mainly applied to vibration diagnosing of large rotating machines such as steam turbines, gas turbines and pumps.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional diagnostic device.
A rotary machine 7 such as a large pump is attached to the gantry 8, and a large number of vibration sensors 5 are provided on the rotary machine 7 or its casing, and the vibration signals thereof are sent to the diagnostic device body 4 via an amplifier 6. This is the configuration to be input. In such a conventional diagnostic device, a vibration signal from a large number of vibration sensors 5 attached to the target rotary machine 7 is input to the diagnostic device main body 4 via an amplifier 6, and the obtained vibration data and a load indicating an operating state are obtained. Vibration measurement was performed by measuring and analyzing the process data 9 such as temperature, pressure, etc. according to the operating conditions.

However, when a change 13 due to an abnormal vibration response occurs as shown in FIG.
However, it was very difficult to estimate the change in natural frequency from the data of only one rotation number 10, and it was not possible to identify the final cause of the abnormality.

In addition, Japanese Patent Publication No. 3-6 filed by the applicant of the present application for vibrating the rotary machine during operation to obtain the natural frequency, damping ratio, stability margin, critical speed, etc. of the rotary machine.
There are known examples of No. 5857 and Japanese Patent Publication No. 3-65858. In both known examples, the damping ratio of the primary critical speed of the shaft system or the allowable excitation coefficient is calculated by performing vibration during the operation of the rotating machine, and the stability and stability of the shaft system depending on the rotation speed or the load is calculated. It is a means of investigating sex margins.

[0005]

The vibration characteristics such as the natural frequency and the damping capacity of the shaft system and casing system of a rotary machine are very important items to be analyzed for vibration diagnosis. It is obtained from the vibration measurement data when the rotational speed changes with time.
However, in a large rotating machine, continuous operation is often performed at a constant rotation speed, the rotation speed does not change so much, and there are very few opportunities to obtain these important vibration characteristics when the rotation speed changes. In addition, when the natural frequency is higher than the operating speed, there is a problem that it is not known when the speed changes, such as when the speed is increased or decreased as described above.

The present invention excites a rotating machine during operation. Excitation is performed at an arbitrary timing regardless of the operating state, and the natural frequency and damping ratio of the shaft system and the frame system are known. It is used for abnormal vibration diagnosis such as estimating the cause of abnormal vibration and quantitative evaluation of abnormality from the correlation with the vibration response of each part detected during operation, by grasping the amount of vibration response to the exciting force.

[0007]

Therefore, according to the present invention,
A vibration exciter is attached to the rotating machine, and means such as an oscillator for controlling the exciter is provided in the vibration diagnosis device. By providing such a vibration function, it is possible to obtain vibration characteristic data such as the natural frequency by performing vibration and performing a vibration test at any timing regardless of the operating state of the rotating machine. Use as a diagnostic device.

That is, according to the present invention, a sensor mounted on a rotating machine or a casing thereof for detecting a vibration response, and a vibration component extracted from the vibration response detected by the sensor are combined to obtain a vibration force and a vibration response. A vibration diagnosing device for analyzing the correlation of the vibration characteristic data to calculate vibration characteristic data, a vibration exciter attached to the rotary machine or its casing, and means for generating vibration of a desired vibration characteristic on the vibration exciter. Done,
There is provided a vibration diagnosis device with a vibration function, wherein the vibration diagnosis device obtains desired vibration characteristic data irrespective of the operating speed of a rotating machine.

[0009]

According to the present invention, a vibrating signal (sine wave or random wave) is output by means for generating a desired vibration characteristic by such means, amplified, and then sent to an exciter. The exciter excites the rotating machine based on the signal. The vibration response generated by the vibration is detected by the vibration sensor attached to the rotating machine, and the detection signal is guided to the vibration diagnosis device, and only the vibration component is extracted to correlate the vibration force with the vibration response. By analyzing, vibration characteristic data such as natural frequency is calculated.

When a sine wave is used as the excitation signal, assuming that the oscillation frequency range is, for example, 10 to 70 Hz, first, the oscillation is performed at a frequency of 10 Hz, and the vibration response of the vibration sensor is obtained. It is possible to obtain the vibration response of the entire region by sequentially repeating the procedure of extracting and analyzing only the 10 Hz component, then exciting / measuring / analyzing 10.1 Hz, and performing the next frequency component up to 70 Hz. it can.

When a random wave is used, 10 to 70H
The vibration generator is controlled by a random signal of z, and the vibration response due to vibration is extracted and separated by analyzing the correlation with the vibration response detected by the vibration sensor.

In any of the methods, since the vibration characteristic data such as the natural frequency and the damping capacity can be obtained from the vibration response obtained, the vibration characteristic data can be obtained irrespective of the operating condition (running or stopped) of the rotating machine. Can be obtained at any timing. Further, even if the natural frequency exists in the region of the rotational speed higher than the operating rotational speed, the vibration characteristic can be easily measured.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of a diagnostic device with a vibration function according to an embodiment of the present invention. FIG. 1 is an example applied to a large-sized pump, and reference numerals 4 to 8 are the same as those of the conventional apparatus shown in FIG. A large pump, that is, a rotary machine 7 is installed on the gantry 8, and vibration sensors 5 are attached to the rotary machine 7 or the casing thereof. The signal from the vibration sensor 7 is input to the diagnostic device body 4 via the amplifier 6. A vibrator 1 is further attached to the upper part of the casing of the rotating machine 7, and the vibrator 1 is connected to an oscillator 3 connected to a diagnostic device body 4 via a power amplifier 2. Further, process data 9 such as load, temperature, pressure, etc. indicating the operating state of the pump is input to the diagnostic device body 4.

With this configuration, as in the conventional case, the vibration diagnosis during operation is performed from the vibration data during operation obtained from the vibration sensor 5 and the process data 9 such as load, temperature, pressure, etc. indicating the operation condition, and According to a command from the diagnostic device body 4, the oscillator 3 is oscillated at a desired frequency, the vibrator 1 is vibrated via the power amplifier 2, and the rotary machine 7 is vibrated. The vibration response is detected by the vibration sensor 5, guided to the diagnostic device main body 4 via the amplifier 6, only the vibration frequency component is extracted, and the vibration characteristic data is analyzed.

The vibration exciter 1 may be of a hydraulic type or an electromagnetic type or an unbalanced motor type (exciter utilizing centrifugal force by rotating a disk having an unbalanced weight), and the power amplifier 2 as well. Any device for controlling the vibration exciter 1 may be used.

FIG. 2 shows the vibration response,
FIG. 2A shows the characteristics of the vibration test measurement range during operation and the vibration response, and the measurement range is more than the “area measured at the time of rotation change” 11 such as speed up and speed down and the operating speed 10. It is composed of a high frequency "area in which only an excitation test is known" 12. As can be seen from this figure (a), conventionally, the natural frequency lower than the operating rotational speed 10 can be measured in the region of 11 when the rotational speed changes between up and down speeds.
The information of higher natural vibration cannot be obtained from the operating condition in the "area in which only the vibration test is known" 12 because the rotational speed of a large rotating machine such as a pump changes substantially constant.

However, by using the vibrating function according to the present invention, it is possible to grasp the vibration characteristics of a higher natural frequency higher than the operating speed at any timing regardless of the operating speed. it can. For example, as shown in FIG. 2B, when a high-order natural frequency causes a change 13 due to an abnormality as shown by a dotted line, a vibration change also occurs at an operating speed of 10, but the driving function is used. It is possible to easily and clearly detect the abnormality by vibrating the vibration exciter 1 in the region 12 of the rotational speed higher than the rotational speed 10 and inputting its response to the diagnostic device main body 4.

[0018]

As described above in detail, in the present invention, a vibration exciter is provided in the vibration diagnosis device for calculating the vibration characteristic data by the signal from the sensor for detecting the vibration response of the rotating machine, and the desired vibration is obtained. Since the device for vibrating the vibration exciter by the means for generating the vibration characteristic of No. 1 has the following remarkable effects.

(1) Obtaining vibration characteristic data such as the natural frequency and damping capacity of a shaft system and a casing system of a vibration diagnostic device for a rotary machine at any timing regardless of the operating state (during operation or stop). You can

(2) It is possible to measure the vibration characteristic data even if the natural frequency exists at a rotational speed higher than the operating rotational speed. Further, in the conventional diagnostic device, the vibration response to the unknown excitation force is measured, but in the present invention, the excitation force from the exciter can be easily measured, and the vibration response to the known excitation force is As a result, the degree of abnormality of abnormal vibration and quantitative evaluation are further enhanced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vibration diagnosis device with a vibration function according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a vibration measurement range and its vibration response during operation of a rotary machine, where (a) shows a state without abnormality,
Each of (b) shows a state in which an abnormality occurs in the natural frequency higher than the operating speed.

FIG. 3 is a configuration diagram of a conventional vibration diagnostic device.

[Explanation of symbols]

 1 Exciter 2 Power amplifier 3 Oscillator 4 Diagnostic device body 5 Vibration sensor 7 Rotating machine 10 Operating speed 11 Area measured when the rotation changes 12 Area where only the vibration test is known 13 Change due to abnormality

Claims (1)

[Claims] 1. A sensor mounted on a rotating machine or its casing for detecting a vibration response, and a vibration component is extracted from the vibration response detected by the sensor to analyze the correlation between the vibration force and the vibration response. A vibration diagnostic device for calculating vibration characteristic data, a vibration exciter attached to the rotary machine or its casing, and means for generating vibration of a desired vibration characteristic on the vibration exciter, A vibration diagnosing device with a vibrating function, wherein desired vibration characteristic data is obtained by the vibration diagnosing device irrespective of an operating speed of a rotating machine.