JPH0772025A - Looseness detector for coupled part - Google Patents

Abstract

PURPOSE:To detect the presence of loosening without being influenced by noises or the like caused by mechanical vibration from the outside. CONSTITUTION:This apparatus is provided with a jetting nozzle 10 to jet a fluid 11 to a coupled part to be measured, a detection means which detects the behavior of the coupled part during the jetting of the fluid with the jetting nozzle 10 to be turned to a signal, for example, an acceleration sensor 5, a CCD camera 12 to photograph the behavior of the coupled part during the jetting of the fluid with the jetting nozzle 10 and a data recorder 8 and a video tape recorder 15 to record a detection signal obtained by the acceleration sensor 5 and an image signal obtained by the CCD camera 12. How the coupled part loosens, is detected based on both a detection signal waveform and the image signal recorded on the data recorder 8 and the video tape recorder 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for detecting a fixing state of a locking member, and more particularly to a fastening portion for detecting a fixing state of a fastening portion composed of bolts and nuts in each device of a nuclear power plant. The present invention relates to a looseness detecting device.

[0002]

2. Description of the Related Art Vibration caused by fluid flow, mechanical vibration,
In a device that undergoes repeated expansion / contraction due to heat, there may occur a problem that a fastening member such as a bolt, a nut, or a fixing pin of a fastening portion is loosened during use.
However, conventionally, as a method of detecting such looseness, visual detection, detection by measuring the tightening torque, and the like have been performed.

However, since many of the devices used in, for example, a nuclear power plant are in a high radiation environment, it is impossible for a person who carries out the looseness detection measurement to approach the detection location. Therefore, a method has been considered in which a fluid is ejected to the fastening portion to be measured, the behavior of the fastening portion at that time is recorded as a waveform signal, and the presence or absence of looseness is determined.

FIG. 2 shows an outline of the device configuration. In the figure, the support pin 21 and the nut 22 are screwed and fastened in water in the core cistern of the reactor vessel with the guide tube bottom plate 26 sandwiched therebetween, and constitute a fastening portion to be measured.

A slit is formed at the tip of the support pin 21, and a detent metal fitting 23 is fitted into this slit. Further, a stop pin 24 is locked so as to penetrate the nut 22 at a right angle to its axial direction, and the detent metal fitting 23 and the stop pin 24 are joined at a welded portion 25.

However, a jet 28 is jetted from the above-mentioned fastening portion by the jet nozzle 27 which is set by remote control of a robot or the like.
Guess The excited vibration of the nut 22 at that time is detected by a signal detector 29 including an acceleration sensor or the like which is also set by remote control of a robot or the like, and an amplifier (in the figure, “Amp”) is detected.
Recorder 31 after amplification with a constant amplification rate via 30
It will be recorded in. In the above-mentioned configuration, the person who performs the measurement determines whether or not the fastening portion is loose by looking at the signal waveform recorded by the recorder 31.

[0007]

However, in the looseness detecting device as shown in FIG. 2, since the presence or absence of the looseness is determined by the signal waveform, the signal detected by the signal detector 29 is externally detected. The noise due to the mechanical vibration may be superimposed on the signal waveform, and it may be difficult to determine looseness.

The present invention has been made in view of the above situation, and its object is to reliably detect the presence or absence of looseness without being affected by noise or the like due to external vibration. An object is to provide a looseness detecting device for a fastening portion.

[0009]

That is, the present invention detects an injection nozzle for injecting a fluid to a fastening portion to be measured, and a behavior of the fastening portion when the fluid is ejected by the injection nozzle to be signaled. Detecting means and an image of the behavior of the fastening portion when the fluid is jetted by the jet nozzle, for example, a CCD
An image pickup means such as a camera, and a recording means for recording the detection signal obtained by the detection means and the image signal obtained by the image pickup means, and the detection signal waveform and the image signal recorded in the recording means. The loosening condition of the fastening part is detected by both of them, and the behavior due to the vibration of the fastening part can be visually confirmed at the same time as the signal waveform, so it affects the noise due to mechanical vibration from the outside. Therefore, the presence or absence of looseness can be reliably detected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a conceptual configuration of the device, and since the configuration of the fastening portion itself to be measured is the same as that shown in FIG. 2, the same parts are denoted by the same reference numerals and the description thereof is omitted. To do.

Therefore, the nut 22 is a clamp fitting in which the bridge-shaped support fitting 1 is provided inside one of the base portions thereof.
Hold by 2. This is to clamp or release the nut 22 by causing the clamp metal fitting 2 to move back and forth with respect to the nut 22 by the pressure water that is pressurized by the water pressure unit 3 and is introduced into the support metal fitting 1 through the water supply and drainage pipe 4. .

An acceleration sensor 5 is embedded on the inner surface side opposite to the base of the support fitting 1 with the nut 22 interposed therebetween, and an output signal of the acceleration sensor 5 is a charge amplifier (in the figure, "Am").
(denoted as "p") 6 and amplified by a constant amplification factor and sent to the analyzer 7, where the signal waveform is analyzed.
Then, the analysis result is recorded and saved as it is by the data recorder (indicated as "rec" in the figure) 8.

In addition, in the central portion of the bridge of the support fitting 1,
An injection nozzle 10 is provided which injects the fluid 11 pressurized by the pump 9 towards the top of the nut 22. In the vicinity of the upper part of the nut 22, a dimmer 16 for dimming and irradiating the light source from the illumination member 17 and an underwater CCD camera 12 for imaging the upper part of the nut 22 by the illumination of the dimmer 16 are installed. The behavior of the upper part of the nut 22 caused by the fluid 11 jetted from the jet nozzle 10 is imaged. This underwater CCD camera 12
The image signal obtained in step 1 is displayed and output on the monitor display device 14 under the control of the central control unit 13 and recorded by the video tape recorder (VTR) 15.

In the above-mentioned structure, the support metal fitting 1 is installed by remote operation underwater so that the base portion of the support metal fitting sandwiches the nut 22, and the clamp metal fitting 2 is moved forward by the pressure water pressurized by the water pressure unit 3. Clamp the nut 22. Also,
The dimmer 16 and the underwater CCD camera 12 are placed opposite to the nut 22 which is also clamped by underwater remote control.

The fluid 11 pressurized by the pump 9 is jetted from the jet nozzle 10 to the head of the nut 22 to be measured, and the excitation vibration of the nut 22 caused by this jet is accelerated by the acceleration sensor 5.
The data is recorded on the data recorder 8 via the charge amplifier 6 and the analyzer 7, and at the same time the underwater CCD camera 12 is detected.
Monitor display device via the central control unit 13
Visualize with 14 and record with videotape recorder 15.

As described above, since the excited vibration of the fastening portion can be visually confirmed at the same time as the signal waveform, noise caused by mechanical vibration from the outside may be detected depending on whether or not the signal waveform and the viewed content match. The presence or absence of looseness can be reliably detected without being affected.

[0017]

As described above, according to the present invention, an injection nozzle for injecting a fluid to a fastening portion to be measured and a behavior of the fastening portion when the fluid is ejected by the injection nozzle are detected and signalized. Detecting means, an image capturing means such as a CCD camera for capturing the behavior of the fastening portion when the fluid is ejected by the ejection nozzle, a detection signal obtained by the detecting means and an image signal obtained by the image capturing means. And a recording means for recording the detection signal waveform recorded in the recording means and the image signal for detecting the loosening state of the fastening portion, and the behavior of the fastening portion due to vibration is signaled. Since it is possible to visually confirm at the same time as the waveform, it is possible to provide a looseness detecting device for the fastening portion that can reliably detect the presence or absence of looseness without being affected by noise or the like due to external mechanical vibration. .

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a conventional looseness detection device.

[Explanation of symbols]

1… Support bracket, 2… Clamp bracket, 3… Water pressure unit,
4… Water supply / drainage pipe, 5… Accelerometer, 6… Charge amplifier, 7… Analyzer, 8… Data recorder, 9… Pump, 10
... injection nozzle, 11 ... fluid, 12 ... underwater CCD camera, 13 ...
Central control unit (CCU), 14 ... Monitor display device, 15
… Video tape recorder, 16… Dimmer, 17… Lighting member,
21 ... Support pin, 22 ... Nut, 23 ... Rotation stop fitting, 24 ... Stop pin, 25 ... Weld, 26 ... Guide tube bottom plate, 27 ... Injection nozzle, 29 ... Signal detector, 30 ... Amplifier, 31 ... Recorder .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Ikegami 2-1-1, Niihama, Arai-cho, Takasago-shi, Hyogo Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] 1. A jetting means for jetting a fluid to a fastening portion to be measured, a detecting means for detecting a behavior of the fastening portion when the fluid is jetted by the jetting means, and the fastening when the fluid is jetted by the jetting means. A waveform of the detection signal recorded in the recording means, comprising: an imaging means for imaging the behavior of the part; and a recording means for recording the detection signal obtained by the detection means and the image signal obtained by the imaging means. A looseness detecting device for a fastening portion, characterized by detecting a looseness state of the fastening portion based on the image signal and the image signal.