JPH09210973A - Foreign matter sensing/removing method, device and manufacturing line for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and quickly sense any foreign matter in a piping or a vessel without requiring labor of an operator even in the process of manufacture or installation, before service after installation, or before re-use after maintenance/inspection. SOLUTION: A piping 1 is fitted with an elastic wave sensor 2, and air compressed by a compressor 4 is blown into the piping 1. If any foreign matter exists, it collides with the piping so cause generation of elastic waves. The generated elastic waves are sensed by the elastic wave sensor 2, and the waveform level is judged by a judging circuit 9, and if a specified level is exceeded, an indication of foreign matter existence is given in the display part 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to foreign matter detection and foreign matter removal technology applicable to pipes and containers used in structures such as nuclear power structures, power generation facilities, and chemical plants.

[0002]

2. Description of the Related Art After welding a pressure vessel or piping, welding spatter may remain in the vessel or piping. Moreover, in order to increase the strength of the pipe, shot peening is performed on the inner peripheral portion of the pipe, but the shot at that time may remain. At the time of shipment from the factory, in order to confirm the presence or absence of residue, the inside of pipes and containers was inspected visually or by optical fiber, and after confirming that there was no residue, they were shipped.

The same applies to the construction of chemical plants and power plants. That is, if the spatter remains inside the pipes during the welding work when joining the pipes, it may cause the strainer to be clogged, and in severe cases, may cause the plant to stop. Therefore, there has been a demand for a technique capable of detecting foreign matters (residues) inside the pressure vessel or the pipe from the outside.

As a conventional technique capable of meeting the above-mentioned needs, there are foreign matter detecting devices described in, for example, Japanese Patent Laid-Open Nos. 58-223744 and 59-28656.

In this conventional technique, a subject such as a pipe is hit with a hammer. Due to the impact at that time, foreign matter inside the pipe jumps and collides with the pipe. AE generated during the collision
The (Acoustic Emission) signal is detected by an AE sensor mounted on the pipe to detect foreign matter in the pipe.

In addition to the above, as in the in-pipe foreign matter detecting device in the fluid disclosed in Japanese Patent Laid-Open No. 4-235380, for example, an AE sensor is attached to a curved portion of a pipe in a cooling water pipe of a reactor or the like, When foreign matter is mixed in the flowing cooling water, the foreign matter is detected by the sensor for detecting AE generated when the foreign matter rides on the flow of the cooling water and collides with the inner wall of the curved portion of the pipe. When a metal foreign matter is mixed inside the gas insulated equipment as in the metal foreign matter detection apparatus for gas insulated equipment described in Japanese Patent No. 167466, when a voltage of a predetermined commercial frequency is applied to the high voltage conductor, the metal foreign matter is generated. By utilizing random bouncing on the inner surface of the metal container due to electric force, the ultrasonic wave signal generated when a metal foreign object collides with the inner surface of the metal container by this bouncing is detected by the AE sensor, That allows detecting the genus foreign matter from the outside is proposed.

[0007]

Among the above-mentioned conventional techniques, JP-A-58-223744 and JP-A-59-2 are known.
The hammering type foreign matter detection device described in Japanese Patent No. 8656 is an effective method for foreign matter detection, but is difficult to use in the following cases. That is, (1) When the pressure vessel and the piping are large, and the foreign material does not bounce off by hammering performed by humans.

(2) When the pressure vessel and the pipe resonate by hammering and vibrate indefinitely like a temple bell (more than the time when foreign matter falls).

When the above-mentioned conditions are satisfied, the hammering type foreign matter detecting device cannot detect the foreign matter.

The foreign matter detecting device described in Japanese Patent Laid-Open No. 4-235380 is applicable to foreign matter detection when foreign matter is mixed in a fluid (for example, cooling water) used in the piping. If it has not been used yet (specifically,
It is not possible to detect residual spatter or residual shot peening material, etc., caused by pipe manufacturing, installation, after installation, before use, after maintenance and inspection before reuse), or by welding.

The foreign matter detecting device described in Japanese Patent Laid-Open No. 2-167466 is not applicable except for a container equipped with a high voltage conductor.

The object of the present invention is, even in the process of manufacturing, installation, after use, before use, after maintenance and inspection, before reuse, etc.
It is an object of the present invention to provide a foreign matter detection and foreign matter removal technique capable of easily detecting a foreign matter in a pipe or a container in a short time and without the operator's hand.

[0013]

In order to achieve the above object, the present invention basically proposes the following foreign matter detecting or removing method and an apparatus for carrying out these methods.

That is, the first aspect of the present invention relates to a foreign matter detecting method, wherein at least one of the pipe and the container is in the process of manufacturing, installation, use after installation, and before reuse after maintenance and inspection. By blowing away the foreign matter remaining in the pipe or container using a device that ejects fluid, by detecting the elastic wave generated when the blown foreign matter collides with the pipe or container using the elastic wave detection sensor, The feature is that residual foreign matter is detected.

That is, a fluid ejecting device (for example, an air compressor) is provided inside a pipe or a container which is a foreign object detection target.
By injecting a jetting fluid (for example, compressed air) by using, the foreign matter (for example, a residue such as welding spatter or shot peening material) remaining in the pipe or the container is blown off. The ejected foreign matter collides with the inner wall of the pipe or the container.
Upon collision, a part of the collision energy is converted into elastic waves. The elastic wave signal is detected by an elastic wave detection sensor mounted on the outer wall (or the inner wall) of the pipe or the pressure vessel.

In this way, residual foreign matter can be detected even when at least one of the pipe and the container is in the process of manufacturing, installation, after use, before use, and after maintenance and inspection before reuse. You can

A second aspect of the present invention relates to a foreign matter removing method, which includes piping,
At least one of the containers is manufactured, installed, and used after installation,
During any one of the processes after maintenance and before reuse, when a foreign substance remaining in the pipe or container is blown off using a device that ejects fluid, and the blown foreign substance collides with the pipe or container, The generated elastic wave is detected by using an elastic wave detection sensor, and the blowout is repeated or continued until it is confirmed by the output signal of the elastic wave detection sensor that there is no residual foreign matter in the pipe or the container. Characterize.

That is, as described in the first aspect of the invention, by sending the jetted fluid into the pipe or the container, the remaining foreign matter is blown off while colliding with the inner wall of the pipe or the like. Waves are generated, but if this blowing is repeated or continued, the foreign matter is finally discharged outside the pipe or the container. In this way, when the foreign matter is removed from the pipe or the container, the elastic wave signal is not output. Therefore, if it is confirmed via the output signal of the elastic wave detection sensor that there is no foreign matter in the pipe or container, the foreign matter can be blown off repeatedly or continuously (that is, the injection fluid can be repeatedly fed into the pipe. , By continuously supplying), foreign matter can be removed by reliably and efficiently sending the injection fluid. Also,
It has the rationality that it can be used as a foreign matter blowing means used for foreign matter removal and foreign matter detection.

A third invention is an invention relating to a foreign matter detecting device which can be used for carrying out the above first and second inventions, in which at least one of a pipe and a container is manufactured, installed, after use, before use, maintenance and inspection. When in any one of the following processes before reuse, a device capable of blowing off the foreign matter remaining in the pipe or the container, and an elastic wave generated when the foreign matter collides with the pipe or the container. It is characterized by comprising an elastic wave detection sensor for detecting, and a determination means for determining the presence or absence of foreign matter from the output signal of the elastic wave detection sensor.

As a concrete example of such a foreign matter detecting device, for example, when a foreign matter blown off as described above collides with a pipe or a container to generate an elastic wave, the elastic wave is detected by the elastic wave detecting sensor. Detecting and amplifying the output signal of this elastic wave detection sensor by an amplifier, and if the output voltage level of the amplifier is above a predetermined level, it is judged that there is a foreign object in the pipe or container using the judgment circuit. There is.
Further, instead of this, it is also proposed to judge that there is a foreign substance in the pipe or the container when the number of waveforms output from the amplifier is a predetermined number or more.

That is, when there is no foreign matter, the elastic wave signal is not detected, but when there is a foreign matter, the presence or absence of the foreign matter can be detected from the outside because the waveform level and the number of occurrences of the elastic wave signal increase.

Since these foreign matter detecting devices are provided with a device capable of blowing off the foreign matter remaining in the pipe or the container and the elastic wave detecting sensor, the foreign matter removing operation as in the second aspect of the invention is also performed. This makes it possible to combine foreign matter detection and foreign matter removal.

[0023]

Embodiments of the present invention will be described with reference to the drawings. Here, a method for detecting a foreign substance (residual substance) in the pipe will be described as an example.

FIG. 1 shows a block diagram of a foreign matter detecting apparatus according to the present invention.

In this embodiment, the elastic wave detection sensor 2 is mounted on the outer wall of the pipe 1. The elastic wave detection sensor 2 is an AE
It is a sensor such as a sensor or accelerometer that can detect elastic waves propagating in the pipe.

The air compressor 4 has its nozzle 3 inserted into the pipe 1 as necessary, and sends compressed air (a compressed gas such as nitrogen may be used) into the pipe 1 through the nozzle 3. The nozzle 3 is set in an air jet form having a conical spread so that the compressed air blows out toward the inner wall of the pipe 1 as shown by the arrow in the figure. Therefore, when the foreign matter 5 remains in the pipe 1, the foreign matter is blown away by the energy of the compressed air and collides with the pipe 1.

Further, the nozzle 3 is equipped with a guide mechanism 11, which is supported by the guide mechanism 11 at a central position in the pipe 1 and is capable of smoothly moving back and forth in the pipe. The nozzle 3 moves in the pipe 1 without being biased while being guided by the guide mechanism 11, so that the guide mechanism 11 uniformly blows compressed air to the entire circumference of the inner wall of the pipe 1 at each position in the entire length of the pipe 1. The guide mechanism 11 is configured, for example, by disposing guide rollers around the nozzle 3 in four directions. The hose 12 of the air compressor 4 is the nozzle 3
Is set to a length that allows the pipe 1 to move over the entire length.

The air compressor 4 is installed either as a part of the pipe 1 for manufacturing or a structure (for example, a nuclear power plant, a power plant, a chemical plant, etc.), before use after installation, and after reuse after maintenance inspection. In one process,
The nozzle 3 is inserted into the pipe 1 to blow away foreign matter remaining in the pipe 1 (for example, spatter generated by pipe welding, shots remaining by shot peening during the pipe manufacturing process). Part of the energy when the blown foreign matter 5 collides with the pipe 1 is converted into an elastic wave 6 and propagates in the pipe, and the elastic wave 6 is detected by the elastic wave detection sensor 2.

The output of the elastic wave detection sensor 2 is amplified by the amplifier 7, and then the elastic wave component is extracted by the high-pass filter 8 and input to the foreign matter determination circuit 9. The high-pass filter 8 uses, for example, a filter that extracts frequencies of 200 KHz or higher. A filter of 200 KHz or less picks up a collision noise (noise) when the air ejected from the nozzle 3 collides with the inner wall of the pipe 1, so that it is difficult to detect the elastic wave, but a 200 KHz high-pass filter is used. As a result, it is possible to clearly detect the elastic wave generated by the collision of the foreign matter.

FIG. 2 shows an example of a detection waveform of the elastic wave detecting sensor 2 when a foreign substance is present.

As compared with the case where there is no foreign matter in the pipe 1, the presence of the foreign matter inside the pipe 1 causes the waveform level of the elastic wave to extremely increase. The determination circuit 9 monitors the waveform level (for example, the average value), and when a signal of a predetermined level or higher is input, outputs a signal indicating that there is a foreign substance to the display unit 10. Regarding the display method of the display unit 10, for example, the presence or absence of foreign matter is visually displayed by an LED. Alternatively, a voice display method may be adopted in which the buzzer sounds only when there is a foreign object.

The judgment circuit 9 can be simply constructed. Use the waveform level meter and activate the limiter when the level is exceeded. Alternatively, a comparator may be used to count the number of output pulse waveforms generated, and when a predetermined count value is exceeded, a signal may be transmitted to the display unit 10. In the former case, it is determined that there is a foreign substance when the output level reaches a predetermined value or more by integrating waveforms, whereas in the latter case, pulse counting is performed in waveform units, so that a finer level is detected. Enables foreign object detection.

FIG. 3 shows an application example of the present invention. The foreign matter detection device 13 (the device 13 includes the elastic wave detection sensor 2, the nozzle 3, the air compressor 4, the amplifier 7, the high-pass filter 8, the determination circuit 9, the display unit 10) of the pipe 1 manufactured in the pipe manufacturing line 14 is described above. Is a total display)
To inspect. If a pipe containing foreign matter is detected, the foreign matter removal process is performed and then the inspection is performed again, and only the pipe that passes the inspection is shipped. Therefore, it becomes possible to prevent the shipment of the pipe containing the foreign matter.

Although foreign matter detection has been described in the above embodiment, the following foreign matter removing work can be performed by using this foreign matter detecting device 13. That is, since the presence or absence of foreign matter in the pipe 1 can be confirmed by the output signal of the elastic wave detection sensor 2 through the display unit 10, the foreign matter is blown off by the air compressor 4 until it is confirmed through the display unit 10 that there is no foreign matter. Repeat or continue. Specifically, for example, by inserting the nozzle 3 into one end of the pipe 1 and injecting air from the starting end (one end) position thereof, the foreign matter in the region where the air injection is vigorous is blown off. . Therefore, since the elastic wave signal is not detected in the blown-out area, there is already no foreign matter in the area. When the elastic wave signal is no longer detected in this way, the nozzle 3 is advanced one step further in the pipe 1 and air is again jetted through the nozzle 3.

By repeating such an operation or continuously operating, the foreign matter is finally discharged to the outside of the pipe, and when the foreign matter is removed from the pipe, the elastic wave signal is not output. Therefore, until it is confirmed via the output signal of the elastic wave detection sensor that the foreign matter is eliminated from the inside of the pipe or the container, the blown foreign matter can be repeatedly blown or continuously performed to reliably and efficiently send compressed air. Enables foreign matter removal. Further, there is a rationality that can be used as a foreign matter blowing means used for foreign matter removal and foreign matter detection.

In the example of the present invention, the inspection example in the manufacturing process of the pipe was mainly described, but it is also applicable to various vessels such as a reactor pressure vessel, and in addition to the above-mentioned usage, For example, it is also possible to detect bolts and nuts left in the pipe during repair or construction of a power plant, that is, to use as loose parts monitoring.

Further, the fluid for blowing off the foreign matter is not limited to air, but nitrogen gas or jet water can also be used. Among them, in the case of nitrogen gas, for example, when foreign matter detection is performed immediately after welding a pipe or the like, there is an advantage that the welded portion can be prevented from being oxidized even if the welded portion is sprayed.

[0038]

According to the first aspect of the present invention, even in the process of manufacturing or installing a pipe or container, before use after installation, before reuse after maintenance inspection, etc., foreign matter in the pipe or container is removed. It can be detected from outside the piping, outside the container, etc. in a short time and easily and in real time without the need for the operator's hand.

According to the second and third aspects of the invention, it is possible to detect foreign matter in the pipe or the container and remove the foreign matter by using a combined device, and it is possible to remove the foreign matter without waste.

[Brief description of drawings]

FIG. 1 is a block diagram of a foreign matter detection device according to the present invention.

FIG. 2 is an explanatory diagram showing a waveform example of an elastic wave signal detected when a foreign substance is present.

FIG. 3 is an explanatory diagram showing an application example of a foreign matter detection device in a pipe manufacturing line.

[Explanation of symbols]

1 ... Piping, 2 ... Elastic wave detection sensor, 3 ... Nozzle, 4 ... Air compressor, 5 ... Foreign matter, 6 ... Elastic wave, 7 ... Amplifier,
8 ... High-pass filter, 9 ... Foreign matter determination circuit, 10 ... Display unit, 13 ... Foreign matter detection device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keizaburo Suzuki 3-2-2, Saiwaicho, Hitachi, Ibaraki Prefecture Hitachi Engineering Service Co., Ltd.

Claims (8)

[Claims] 1. A pipe using a device for injecting a fluid when at least one of the pipe and the container is in the process of manufacturing, installation, after use, before use, or after maintenance and inspection before reuse. Or foreign matter remaining in the container is blown away, and the foreign matter characterized by detecting the acoustic wave generated when the blown-out foreign matter collides with a pipe or a container using an elastic wave detection sensor is detected. Detection method. 2. The foreign matter detecting method according to claim 1, wherein the device that injects the fluid is a compressor that sends compressed air or compressed nitrogen gas into the pipe or the container. 3. Inside the pipe using a device for injecting a fluid, when at least one of the pipe and the container is in the process of manufacturing, installation, after use, before use, and after maintenance and inspection before reuse. And the foreign matter remaining in the container are blown away, and the elastic wave generated when the blown-out foreign matter collides with the pipe or the container is detected using an elastic wave detection sensor, and the output signal of the elastic wave detection sensor is used in the pipe or the container. A foreign matter removing method, characterized in that the blow-off is repeated or continued until it is confirmed that the remaining foreign matter is gone. 4. When at least one of the pipe and the container is in the process of manufacturing, installation, after use, before use, or after maintenance and inspection before reuse, foreign matter remaining in the pipe or the container is removed. A device capable of being blown off, an elastic wave detection sensor for detecting an elastic wave generated when the foreign matter collides with a pipe or a container, and a determination for determining the presence or absence of a foreign matter from the output signal of the elastic wave detection sensor And a means for detecting foreign matter. 5. When at least one of the pipe and the container is in the process of manufacturing, installation, after use, before use, or after maintenance and inspection before reuse, foreign matter remaining in the pipe or the container is removed. A device capable of being blown off, an elastic wave detection sensor for detecting an elastic wave generated when the foreign matter collides with a pipe or a container, and an amplifier for amplifying an output signal of the elastic wave detection sensor, Foreign matter detection, characterized by comprising a determination circuit for determining that there is a foreign matter in the pipe or the container when the output voltage level of the amplifier is equal to or higher than a predetermined level, and an indicator for displaying the determination result. apparatus. 6. The foreign matter remaining in the pipe or the container when at least one of the pipe and the container is in the process of manufacturing, installation, after use, before use, and after maintenance and inspection before reuse. A device capable of being blown off, an elastic wave detection sensor for detecting an elastic wave generated when the foreign matter collides with a pipe or a container, and an amplifier for amplifying an output signal of the elastic wave detection sensor, When the number of waveforms output from the amplifier is equal to or more than a predetermined number, a determination circuit that determines that there is a foreign substance in the pipe or the container, and a display that displays the determination result are provided. Foreign matter detector. 7. The device capable of blowing off the foreign matter comprises a compressor whose nozzle can be introduced into the pipe or the container and which is set to blow compressed air or compressed nitrogen gas, 7. The foreign matter detection device according to claim 4, wherein the elastic wave detection sensor is an AE sensor or an acceleration pickup. 8. A foreign matter detection device according to claim 4 is provided, and the presence or absence of foreign matter is inspected in a manufactured pipe or container to detect the presence of foreign matter. In this case, the manufacturing line is characterized in that after the foreign matter removing process is performed, the inspection is performed again and only the pipes or containers that have passed the inspection are shipped as products.