JPS58108418A - Vibration monitor - Google Patents

Abstract

PURPOSE:To continuously monitor the generation of an abnormality, by providing a vibration monitor with a plurality of vibration detectors for individually detecting vibration components of an object being inspected, an adding/subtracting device adapted to feed therein electric signals through amplifiers and subject them to adding/subtracting processes, and a comparator circuit adapted to feed therein the output of an effective value output circuit feeding therein the output of a band-pass filter. CONSTITUTION:Vibration components of an object being inspected are converted into electric signals by vibration detectors 1-4 and amplified by respective amplifiers 6 and are then fed into a decision unit 7, where the electric signals are subjected to adding/subtracting processes by an adding/subtracting device 8 so as to be a composite signal. Position and negative signs denote adding and subtracting processes respectively, and the positive or negative signs are selected according to the vibration mode being monitored and the sensitivity directions of the detectors 1-4. The effective value of the output waveform from a band-pass filter 9 which draws out only the characteristic frequency component to which attention is paid is compared with a predetermined set value in a comparator circuit 11 to judge the object to be normal or abnormal, and the result is displayed on a display 12.

Description

[Detailed description of the invention] The present invention relates to a vibration monitoring device.

For example, in a nuclear reactor, a vibration monitoring device was conventionally used to detect shock signals caused by collisions of metal pieces (loose elbows) mixed in or generated within the water cooling system. Since the processing method is also selected with attention to the characteristics of the shock signal, the vibration detection ability is relatively low.

The present invention was proposed in view of the above circumstances, and is designed to prevent cooling water from turbulent in nuclear reactors, reactor internal structures, etc.

By monitoring relatively low-frequency steady-state vibration components when excited by the propagation of mechanical vibrations in the coolant, it is possible to detect problems that may occur in the reactor and reactor internal structures, such as melting and welding. Damage to the fixing parts of the village 9 Equipment loose in the trench / Parable
The present invention aims to provide a vibration monitoring device that continuously monitors the occurrence of abnormalities such as entrapment of metal pieces such as metal chips, changes in the flow state of coolant, etc., and improves the reliability of nuclear couplants, etc. by detecting them early. purpose.

To this end, the present invention provides a plurality of vibration detectors that are fixed to a subject and individually detect the vibration components of the subject, and an addition/subtraction system that inputs the outputs of the plurality of vibration detectors through amplifiers and adds or subtracts them. a band v-wave unit that inputs the output of the adder/subtractor, an effective value output circuit that inputs the output of the band v-wave unit, and a comparison circuit that inputs the output of the effective value output circuit. An embodiment in which the present invention is applied to a nuclear reactor will be described with reference to the drawings. FIG. 1 is a system diagram thereof, and FIG. 2 is a diagram showing the circuit configuration of the determination device shown in FIG. 1.

It is a microcosm.

In the above figure, 1 to 4 are respectively attached to the outer periphery of the reactor vessel 6, and 9 are vibration detectors, 6 is an amplifier that amplifies the output of each of the vibration detectors 1 to 4, respectively, 7 is a judgment device according to the present invention, and 8 is a plurality of adders and subtracters that input the output of each amplifier 6 and perform addition and subtraction on the plurality of outputs according to the detected vibration mode;
Reference numeral 9 denotes a bandpass filter that inputs the output of each adder/subtractor 8, an effective value output circuit that inputs the output of the 1ull bandpass filter 9 and outputs its effective value, and 11 a comparison circuit that inputs the output of the effective value output circuit 10. , 12 is a display unit that displays the output of the comparator circuit 11 fi, and the +1-17 system is as follows:
If necessary, use more than one.

In such a device, the vibrations of the reactor vessel 5 are converted into electrical signals by the vibration detectors 1 to 4, amplified by the amplifier 6, and then input to the judgment device 1. The signals 1 to 4 are subjected to addition/subtraction processing and synthesized, and then input to the /4y pass filter 9. Here, the positive and negative signs in the adder/subtractor 8 are used for addition or subtraction (
The sign of the signal is reversed and added).The selection of the positive and negative signs depends on the vibration mode being monitored and the detector 1.
~4 sensitivity directions (detectors 1 to 4 in Figures 1 and 2)
direction of the arrow). For example, in the case of the locking mode of the reactor vessel indicated by the thick arrow in FIG. 1, the signals of detector 1.3 are added, and the signals of detector 2.
By subtracting (adding with the sign reversed) the 40 signals, that is, by superimposing the rocking vibration components captured by each detector 1 to 4 in the same phase, it is emphasized against noise and the ability to discriminate against noise traps is improved. . The band/mother filter 9 matches the central station wave number with the natural frequency of the vibration mode of interest, and the adder/subtractor 8 extracts only the natural frequency component of interest from the synthesized waveform. , the effective value output circuit 10 detects the effective value of the band/9 filter #O output waveform.

A comparison circuit 11 compares a predetermined set value with the effective value of the output of the band/base filter 9 to determine whether it is normal or abnormal, and displays the result on the display section 12. As an example of the judgment zero check in the comparator circuit, set values for two levels, high and low, are determined, and if the effective value of the output of the band/gas filter 9 exceeds the high level set value, an alarm for excessive vibration level is issued. If it falls below the low level set value, it is possible to issue a natural frequency shift) O alarm. In addition, the output of the effective value output circuit 10 is input to the ψ converter instead of the comparator circuit 11 and the display section 12, and subsequent judgments are made by a digital circuit, and the outputs of the plurality of processing systems 8 to 10 are integrated. Bacmeter (e.g. temperature, pressure, coolant rotation speed, vibration level, etc.)
Changes such as adding information to the judgment information may also be considered.

The output signal of each vibration detection system 4t (detectors 1 to 4 and amplifier 6) in the present invention is composed of the following components.

(1) Vibration component of the mode of interest.

(2) Vibration components of non-target modes.

(3) Random vibration components due to ff dynamic noise, etc.

(4) Random signal due to electrical noise.

In order to make accurate judgments, please follow (2), (3), and (4) above.
It is necessary to efficiently remove the o signal. Above (2
) components can be removed by 74 ruta geography using the difference in natural frequencies, but (3) (4) C) above.
? Since the normal vibration component contains the same frequency component 4 as the target vibration component, there is a drawback that it is not possible to perform sufficient noise separation using conventional filter processing alone. However, according to the present invention, the vibration components of the mode of interest are superimposed with the same phase, but the random vibration components are superimposed with a random phase, so the proportion of the vibration component of interest in the composite waveform increases. , the noise reduction effect is exhibited.

In short, according to the present invention, a plurality of Wk*JJ detectors are fixed to a subject and individually detect vibration components of the subject, and the outputs of the plurality of vibration detectors are inputted via amplifiers respectively. an adder/subtractor that performs addition/subtraction; a band F-wave unit that receives the output of the adder/subtractor; an effective value output circuit that receives the output of the band V-wave unit; and a comparison circuit that receives the output of the effective value output circuit. Since a high-performance vibration monitoring device can be obtained by obtaining tA, the present invention is extremely useful industrially.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment in which the present invention is applied to a nuclear reactor, and FIG. 2 is a diagram showing the circuit configuration of the judgment device shown in FIG.
FIG. 1.2, 3.4... Vibration detector, 6... Reactor vessel, 6... Amplifier, 7... Judgment device, 8... Adder/subtractor, 9... Band/arm disc (10 - effective value output circuit, 11... comparison circuit, IJ -... display section. Applicant's sub-agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] a plurality of vibration detectors that are fixed to a subject and individually detect vibration components of the subject; an adder/subtractor that inputs the outputs of the plurality of vibration detectors through amplifiers and performs addition/subtraction; The device is characterized by comprising: a band V wave device to which the output of the band V wave device is input; an effective value output circuit to which the output of the band V wave device is input; and a comparator circuit to which the output of the effective value output circuit is input. vibration monitoring device.