WO2011055901A1

WO2011055901A1 - Nondestructive inspection apparatus using a ferromagnetic bar

Info

Publication number: WO2011055901A1
Application number: PCT/KR2010/006149
Authority: WO
Inventors: 이진이; 전종우; 김정민
Original assignee: 조선대학교 산학협력단
Priority date: 2009-11-03
Filing date: 2010-09-09
Publication date: 2011-05-12
Also published as: KR101111260B1; KR20110048788A

Abstract

According to the present invention, a nondestructive inspection apparatus comprises: a magnetic sensor; a ferromagnetic bar, a signal processor, and a display. The magnetic sensor generates a magnetic field sensing signal corresponding to the magnetic field intensity of an object for inspection. The ferromagnetic bar is installed between the object for inspection and the magnetic sensor. The signal processor converts the magnetic field sensing signal from the magnetic sensor into a displayable format. The display displays the magnetic field sensing signal from the signal processor.

Description

Non-destructive testing device using ferromagnetic rod

The present invention relates to a non-destructive inspection device, and more particularly, to a non-destructive inspection device for inspecting a defect of a test object in which ferromagnetic structures, paramagnetic structures, ferromagnetic materials and paramagnetic materials are mixed.

Nondestructive inspection devices using magnetic phenomena are useful for finding surface defects on the inspection target, back defects near the surface, or internal defects. Non-destructive testing devices can be used to detect defects in large plants and structures used in nuclear power, thermal power, and chemical industries.

In the non-destructive inspection device as described above, the inspection object may be hot or contaminated. In such a case, it is necessary to considerably space the magnetic sensor from the inspection object. In this case, as the signal level range of the magnetic sensor is narrowed, the performance of the defect display is lowered.

Accordingly, there is a problem that the accuracy of the defect inspection is lowered when the inspection object is hot or contaminated.

It is an object of the present invention to provide a non-destructive inspection device that enables the accuracy of defect inspection not to drop even when the inspection object is hot or contaminated.

The non-destructive inspection device of the present invention includes a magnetic sensor, a ferromagnetic bar, a signal processor, and a display.

The magnetic sensor generates a magnetic field sensing signal corresponding to the strength of the magnetic field from the inspection object.

The ferromagnetic rod is installed between the inspection object and the magnetic sensor.

The signal processor converts the magnetic field sensing signal from the magnetic sensor to match the display format.

The display unit displays a magnetic field detection signal from the signal processor.

According to the non-destructive inspection device of the present invention, as the ferromagnetic rod is installed between the inspection object and the magnetic sensor, the magnetic field from the inspection object is magnetized while the ferromagnetic rod is magnetized by the magnetic field from the inspection object. To the sensor.

Therefore, even if the magnetic sensor is significantly spaced from the inspection object when the inspection object is hot or contaminated, as the signal level range of the magnetic sensor changes less, the performance of the defect display is not lowered.

Therefore, even when the inspection target is hot or contaminated, the accuracy of defect inspection may not be reduced.

1 is a view showing a non-destructive inspection device according to a first embodiment of the present invention.

2 to 10 are diagrams showing examples of the ferromagnetic bars of FIG. 1.

FIG. 11 is a detailed view illustrating a hall sensor as an example of the magnetic sensor of FIG. 1.

FIG. 12 is a view illustrating that a cooling unit or a blower unit is added in the non-destructive inspection device of FIG. 1.

13 is a view showing a non-destructive inspection device according to a second embodiment of the present invention.

14 is an exploded perspective view showing that the magnetic sensors and ferromagnetic bars of FIG. 1 are embedded in a case.

15 is a perspective view illustrating a state in which the members of FIG. 14 are coupled.

16-18 are perspective views showing examples of the arrangement of the ferromagnetic bars and magnetic sensors of FIG. 14.

FIG. 19 is a diagram showing that the magnetic sensors of FIG. 14 may be arranged in one plane in two dimensions.

20 is a diagram showing that the magnetic sensors of FIG. 14 may be arranged on one curved surface in three dimensions.

FIG. 21 is a view illustrating that a cooling unit or a blower unit is added in the non-destructive inspection device of FIG. 13.

22 is a view showing an experimental process for comparing the performance of the conventional non-destructive testing device and the non-destructive testing device of FIG. 13 according to the present invention using a direct current magnetic field.

23 is a view showing an experimental process for comparing the performance of the conventional non-destructive inspection device and the non-destructive inspection device of FIG. 13 according to the present invention using an alternating magnetic field.

FIG. 24 is a diagram showing an experimental result when the non-destructive inspection apparatus of the related art uses the DC magnetic field of FIG. 22 and the distance between the sensor array and the first test object is 1 millimeter (mm).

FIG. 25 is a view showing an experimental result when a distance between the sensor array and the first test object is 5 millimeters (mm) using the direct current magnetic field of FIG. 22 with respect to the conventional non-destructive inspection device.

FIG. 26 is a diagram showing an experimental result when the DC magnetic field of FIG. 22 is used and the distance between the sensor array and the first test object is 18 millimeters (mm) with respect to the conventional non-destructive inspection device.

FIG. 27 is a view showing an experimental result when the DC magnetic field of FIG. 22 is used and the distance between the sensor array and the first test object is 22 millimeters (mm) with respect to the conventional non-destructive inspection device.

FIG. 28 is a view showing an experimental result when the DC magnetic field of FIG. 22 is used and the distance between the sensor array and the first test object is 27 millimeters (mm) with respect to the conventional non-destructive inspection device.

FIG. 29 shows experimental results when the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention uses the direct current magnetic field of FIG. 22 and the distance between the sensor array and the first test object is 18 millimeters (mm). Drawing.

FIG. 30 shows experimental results when the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention uses the direct current magnetic field of FIG. 22 and the distance between the sensor array and the first test object is 22 millimeters (mm). Drawing.

FIG. 31 shows experimental results when the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention uses the direct current magnetic field of FIG. 22 and the distance between the sensor array and the first test object is 27 millimeters (mm). Drawing.

FIG. 32 is a view showing the results of experiments in the case where the distance between the sensor array and the second test object is 1 millimeter (mm) using the alternating magnetic field of FIG. 23 with respect to the conventional non-destructive inspection device.

FIG. 33 is a view showing the results of experiments in the case where the alternating magnetic field of FIG. 23 is used for a conventional non-destructive inspection device and the distance between the sensor array and the second test object is 5 millimeters (mm).

FIG. 34 is a view showing the results of experiments in the case where the distance between the sensor array and the second test object is 10 millimeters (mm) using the alternating magnetic field of FIG. 23 with respect to the conventional non-destructive inspection device.

FIG. 35 is a view showing the results of experiments in the case where the distance between the sensor array and the second test object is 18 millimeters (mm) using the alternating magnetic field of FIG. 23 with respect to the conventional non-destructive inspection device.

FIG. 36 is a view showing the results of experiments in the case where the distance between the sensor array and the second test object is 22 millimeters (mm) using the alternating magnetic field of FIG. 23 with respect to the conventional non-destructive inspection device.

FIG. 37 shows experimental results when the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention uses the alternating magnetic field of FIG. 23 and the distance between the sensor array and the second test object is 18 millimeters (mm). Drawing.

FIG. 38 shows experimental results when the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention uses the alternating magnetic field of FIG. 23 and the distance between the sensor array and the second test object is 22 millimeters (mm). Drawing.

1 shows a non-destructive inspection device according to a first embodiment of the present invention.

Referring to FIG. 1, the non-destructive testing device according to the first embodiment of the present invention includes a magnetic field generator 13, a magnetic sensor 12, a ferromagnetic rod 11, a signal amplifier 14, and a signal processor 15. , A display unit 16, a case 18, and a driver 17.

The magnetic field generator 13 applies an electromagnetic field to the inspection object 19.

The magnetic sensor 12 generates a magnetic field sensing signal corresponding to the strength of the magnetic field from the test object 19.

The ferromagnetic rod 11 is installed between the inspection object 19 and the magnetic sensor 12.

The signal amplifier 14 amplifies the magnetic field detection signal from the magnetic sensor 12 and inputs the signal to the signal processor 15.

The signal processor 15 converts the magnetic field sensing signal input from the magnetic sensor 12 through the signal amplifier 14 to match the display format.

The display unit 16 displays the magnetic field detection signal from the signal processor 15.

The case 18 includes a magnetic sensor 12 and a ferromagnetic rod 11.

The drive unit 17 moves the case 18 in the scanning directions X and Y.

According to the non-destructive inspection device of the first embodiment of the present invention as described above, as the ferromagnetic rod 11 is installed between the inspection object 19 and the magnetic sensor 12, the ferromagnetic rod 11 is inspected 19. The magnetic field from the inspection object 19 is transmitted to the magnetic sensor 12 while being magnetized by the magnetic field from the.

Therefore, even when the inspection object 19 is hot or contaminated, even if the magnetic sensor 12 is spaced apart from the inspection object 19 from the position of "Zold" to the position of "Znew", the signal level of the magnetic sensor 12 is reduced. As the range changes less, the performance of the defect display on the display unit 16 is not lowered.

Therefore, even when the inspection target 19 is hot or contaminated, the accuracy of defect inspection may not be reduced.

2 to 10 show examples of the ferromagnetic rod 11 of FIG. 1. 2 to 10, "B" indicates the direction in which the ferromagnetic rod 11 is magnetized by the magnetic field from the inspection object (19 in FIG. 1).

Referring to FIG. 2, the ferromagnetic rod 11 may be cylindrical.

Referring to FIG. 3, in the cylindrical ferromagnetic rod 11, an end portion facing the inspection object 19 may be conical. Accordingly, the magnetic field from the inspection object 19 can be transmitted to the ferromagnetic rod 11 more intensively.

Referring to FIG. 4, the ferromagnetic rod 11 may have a square pillar shape.

Referring to FIG. 5, in the square columnar ferromagnetic rod 11, an end portion facing the inspection object 19 may be a square pyramid. Accordingly, the magnetic field from the inspection object 19 can be transmitted to the ferromagnetic rod 11 more intensively.

Referring to FIG. 6, the ferromagnetic rod 11 may be a triangular prism.

Referring to FIG. 7, in the triangular prismatic ferromagnetic rod 11, an end portion facing the test object 19 may be triangular pyramid shaped. Accordingly, the magnetic field from the inspection object 19 can be transmitted to the ferromagnetic rod 11 more intensively.

Referring to FIG. 8, the ferromagnetic rod 11 may have an inclined shape at one side of the end facing the inspection target 19. Accordingly, when one side of the inspection object 19 has an inclined shape, more accurate inspection is possible.

Referring to FIG. 9, the ferromagnetic rod 11 may have a bead at the end facing the inspection target 19. Accordingly, when a plurality of circular grooves are dug into the inspection object 19, more accurate inspection is possible.

Referring to FIG. 10, the ferromagnetic rod 11 may have a stepped end facing the inspection object 19. Accordingly, when the staircase is formed on the inspection object 19, more accurate inspection is possible.

FIG. 11 shows a Hall sensor in detail as an example of the magnetic sensor 12 of FIG. 1. Referring to FIG. 11, the hall sensor 12 includes a first power terminal 121, a second power terminal 123, a first output terminal 124, and a second output terminal 122.

When a power supply voltage is applied between the first power supply terminal 2001a and the second power supply terminal 123, the magnetic field detection signal corresponding to the strength of the magnetic field incident on the hall sensor 12 is outputted to the first output terminal 124 and the first power supply terminal 124. It is generated between two output terminals 122.

That is, when the electric field and the magnetic field are orthogonal in the hall sensor 12, a potential difference occurs between the first output terminal 124 and the second output terminal 123. The generated voltage signal is input to the signal amplifier 14.

FIG. 12 shows that the cooling unit 81 or the blower 82 is added in the non-destructive inspection device of FIG. 1. In FIG. 12, the same reference numerals as used in FIG. 1 indicate objects of the same function.

Referring to FIG. 12, the non-destructive inspection device of FIG. 1 may further include a cooling unit 81 for cooling the ferromagnetic rod 11. Accordingly, more accurate inspection can be performed when the temperature of the inspection object 19 is high.

In addition, the non-destructive inspection device of Figure 1 may further include a blower 82 for blowing wind to the ferromagnetic rod (11). Accordingly, more accurate inspection can be performed when there is much dust on the inspection object 19.

13 shows a non-destructive inspection device according to a second embodiment of the present invention.

Referring to FIG. 13, the non-destructive testing device according to the second exemplary embodiment of the present invention includes a magnetic field generator 23, a sensor array 22, a rod bundle 21 of a plurality of ferromagnetic bars, a signal amplifier 24, The signal processor 25, the display unit 26, and the case 28 are included.

The magnetic field generator 23 applies an electromagnetic field to the inspection target 29.

In the sensor array 22, a plurality of magnetic sensors are regularly arranged in accordance with the power lines from the power source 27. The sensor array 22 generates magnetic field sensing signals corresponding to the strength of the magnetic field from the test object 29.

The rod bundle 21 of ferromagnetic bars is installed between the inspection object 29 and the sensor array 22.

The signal amplifier 24 amplifies the magnetic field detection signals from the sensor array 22 and inputs the signal to the signal processor 25.

The signal processor 25 converts the magnetic field sensing signals from the sensor array 22 to match the display format.

The display unit 26 displays the magnetic field sensing signals from the signal processor 25.

The case 28 houses a sensor array 22 of magnetic sensors and a rod bundle 21 of ferromagnetic bars.

According to the non-destructive inspection device of the second embodiment of the present invention as described above, as the rod bundle 21 of ferromagnetic rods is installed between the inspection target 29 and the sensor array 22, the rod bundle 21 is inspected. The magnetic field from the inspection object 19 is transmitted to the sensor array 22 while being magnetized by the magnetic field from (29).

Therefore, even when the inspection object 29 is hot or contaminated, even if the sensor array 22 is spaced apart from the inspection object 29 from the position of "Zold" to the position of "Znew" on the Z axis, the sensor array 22 As the signal level range of f varies less, the performance of defect display on the display section 26 does not decrease.

Therefore, even when the inspection target 29 is hot or contaminated, the accuracy of defect inspection may not be reduced.

FIG. 14 shows that the sensor array 22 of the magnetic sensors of FIG. 1 and the rod bundle 21 of ferromagnetic bars are embedded in the case 28 of FIG. 13. 15 illustrates a state in which the members of FIG. 14 are coupled.

Referring to FIGS. 14 and 15, the case 28 includes one member 28a, the other member 28b, and a lower member 28c.

The first guide groove is formed on the inner wall of the one side member 28a. A second guide groove facing the first guide groove is formed on an inner wall of the other side member 28b. A sensor array 22 of magnetic sensors is attached to the inner wall of the lower member 28c.

One side member 28a and the other side member 28b are fastened with screws 33 in a state where the rod bundle 21 of the ferromagnetic rods is inserted into the first guide groove and the second guide groove. In addition, the lower member 28c is fastened to the bottom surface of one side member 28a and the other side member 28b with a screw 33.

Furthermore, in the lower member 28c,

auxiliary light sources

31a and 31b are provided on both sides of the sensor array 22 of the magnetic sensors. In addition,

optical path members

32a and 32b of the

auxiliary light sources

31a and 31b are inserted between the one side member 28a and the other side member 28b.

According to the

auxiliary light sources

31a and 31b and the

light path members

32a and 32b as described above, the user may move the rod bundle 21 and the sensor array 22 inside the case through the

light path members

32a and 32b. You can check the alignment. In addition, since the illumination light is emitted to the inspection target 29 through the

light path members

32a and 32b, the user can quickly recognize the current inspection position.

In the case of Fig. 14, the sensor array 22 of magnetic sensors is arranged on one straight line in one dimension. However, the sensor array 22 of magnetic sensors may optionally be arranged on one plane in two dimensions (see FIG. 19). In addition, the sensor array 22 of magnetic sensors may optionally be arranged on one curved surface in three dimensions.

On the other hand, in the case of Fig. 14, the rod bundle 21 of ferromagnetic rods is arranged on one straight line in one dimension. However, of course, the rod bundle 21 of ferromagnetic rods can be arranged on one plane two-dimensionally.

16-18 show examples of rod bundle 21 of ferromagnetic bars and sensor array 22 of magnetic sensors of FIG. 14. 16 to 18, “B” indicates the direction in which the rod bundle 21 of the ferromagnetic rods is magnetized by the magnetic field from the inspection object (29 in FIG. 13).

Referring to FIG. 16, a rod bundle (21 in FIG. 13) and a sensor array (22 in FIG. 13) may be arranged such that one end of one ferromagnetic rod 21a faces one magnetic sensor 22a.

Referring to FIG. 17, the rod bundle 21 (FIG. 13) and the sensor array 22 (FIG. 13) may be arranged such that the ends of the plurality of

ferromagnetic bars

21b and 21c face one magnetic sensor 22b. have.

Referring to FIG. 18, the rod bundle 21 (FIG. 13) and the sensor array 22 (FIG. 13) may be arranged such that the ends of one ferromagnetic rod 21 d face the plurality of

magnetic sensors

22c and 22d. have.

FIG. 19 shows that the sensor array 22 of the magnetic sensors of FIG. 14 can be arranged on one plane two-dimensionally.

Referring to FIG. 19, the sensor array 22 includes

hall sensors

22a, 22b, 22c, 22d, and 22c arranged in m rows and n columns (but not limited to 4 rows and 4 columns in FIG. 19). Vcc lines L11, L21, L31, L41, m ground lines L12, L22, L32, L42, n first output lines V1 +, V2 +, V3 +, V4 + and n second Output lines V1-, V2-, V3-, V4-.

The Vcc terminals a of each of the Hall sensors belonging to the mth row, where m is a natural number from 1 to m, are connected to the Vcc line Lm1 of the mth row.

The ground terminals c of each of the hall sensors belonging to the m th row are connected to the ground line Lm2 of the m th row.

The first output terminals d of each of the Hall sensors belonging to the nth (where n is a natural number from 1 to n) column are connected to the first output line Vn + of the nth column.

Second output terminals b of each of the hall sensors belonging to the nth column are connected to the second output line Vn− of the nth column.

The switch SW1a applies the positive potential Vcc to the Vcc line L11 of the first row.

The switch SW1b applies a ground potential Vg to the ground line L12 of the first row.

The switch SW4a applies the positive potential Vcc to the Vcc line L41 in the fourth row.

The switch SW4b applies a ground potential Vg to the ground line L42 of the fourth row.

FIG. 20 shows that the magnetic sensors 22 of FIG. 14 can be arranged on one curved surface in three dimensions. In Fig. 20, the same reference numerals as those in Fig. 19 indicate the object of the same function.

Referring to FIG. 20, the magnetic sensors 22 are arranged on a cylindrical surface in three dimensions. In this case, when the inspection object (29 of FIG. 13) is a cylindrical pipe, defects existing inside or outside the cylindrical pipe can be easily inspected.

FIG. 21 shows that the cooling unit 91 or the blowing unit 92 is added in the non-destructive inspection device of FIG. 13. In Fig. 21, the same reference numerals as in Fig. 13 indicate the objects of the same function.

Referring to FIG. 21, in the non-destructive testing device of FIG. 13, a cooling unit 91 for cooling the rod bundle 21 of the ferromagnetic rods may be further included. Accordingly, a more accurate test can be performed when the temperature of the test target 29 is high.

In addition, the non-destructive inspection device of FIG. 13 may further include a blower 92 for blowing air to the rod bundle 21 of the ferromagnetic rods. Accordingly, more accurate inspection can be performed when there is much dust on the inspection object 19.

22 shows an experimental procedure for comparing the performance of the conventional non-destructive inspection device and the non-destructive inspection device of FIG. 13 according to the present invention using a direct current magnetic field.

Referring to FIG. 22, a DC magnetic field is generated by a DC 500 milliampere (mA) driving current in the DC magnetic field generator 13.

In the case of the non-destructive inspection device of FIG. 13 equipped with a rod bundle 21 of ferromagnetic bars, the separation distance between the sensor array 22 from the surface of the first test object 19 is 18 millimeters (mm) and 22 millimeters (mm). And a signal level and a display image of the sensor array 22 were obtained at 27 millimeters (mm), respectively.

In the case of the conventional non-destructive inspection apparatus without the rod bundle 21 of ferromagnetic rods, the separation distance between the sensor array 22 from the surface of the first test object 19 is 1 millimeter (mm) and 5 millimeters (mm). ), A signal level and a display image of the sensor array 22 were acquired at 18 millimeters (mm), 22 millimeters (mm), and 27 millimeters (mm), respectively.

FIG. 23 shows an experimental procedure for comparing the performance of a conventional nondestructive testing device with the nondestructive testing device of FIG. 13 according to the present invention using an alternating magnetic field.

Referring to FIG. 23, an alternating magnetic field is generated by a driving current of alternating current 5 amps (mA) and one kilohertz (KHz) in a coil wound three times by the alternating magnetic field generator 23.

In the case of the non-destructive inspection device of FIG. 13 with the rod bundle 21 of ferromagnetic bars, the separation distance between the sensor array 22 from the surface of the second test object 29 is 18 millimeters (mm), 22 millimeters (mm). And a signal level and a display image of the sensor array 22 were obtained at 27 millimeters (mm), respectively.

In the case of the conventional non-destructive inspection device without the rod bundle 21 of ferromagnetic rods, the separation distance between the sensor array 22 from the surface of the second test object 29 is 1 millimeter (mm) and 5 millimeters (mm). ), Signal levels and display images of the sensor array 22 were acquired at 10 millimeters (mm), 18 millimeters (mm), 22 millimeters (mm), and 27 millimeters (mm), respectively.

In the case of the experiment of FIG. 23, in order to acquire a clearer display image, the defective part of the second test object 29 was operated as a coil of the AC magnetic field generating unit 23.

FIG. 24 illustrates a conventional non-destructive inspection device using the direct current magnetic field of FIG. 22 and having a distance of 1 millimeter (mm) between the sensor array (22 in FIG. 22) and the first test object (19 in FIG. 22). Show signal level and display image.

Referring to FIG. 24, the signal level range of the sensor array 22 at the defect site was about 16. FIG.

FIG. 25 illustrates a conventional non-destructive inspection device using the direct current magnetic field of FIG. 22 and having a distance of 5 millimeters (mm) between the sensor array (22 in FIG. 22) and the first test object (19 in FIG. 22). Show signal level and display image.

Referring to FIG. 25, the signal level range of the sensor array 22 at the defect site was about 1.4.

24 and 25, the distance between the sensor array 22 and the first test object 19 is 5 millimeters (mm) compared to the case of 1 millimeter (mm) (FIG. 24) (FIG. 25). It can be seen that as the signal level range narrows considerably, the display image also blurs.

FIG. 26 illustrates a conventional non-destructive inspection device using the direct current magnetic field of FIG. 22 and having a distance of 18 millimeters (mm) between the sensor array (22 in FIG. 22) and the first test object (19 in FIG. 22). Show the results of the experiment.

FIG. 27 shows a conventional non-destructive inspection device using the direct current magnetic field of FIG. 22 and having a distance of 22 millimeters (mm) between the sensor array (22 in FIG. 22) and the first test object (19 in FIG. 22). Show the results of the experiment.

FIG. 28 illustrates a conventional non-destructive inspection device using the direct current magnetic field of FIG. 22 and having a distance of 27 millimeters (mm) between the sensor array (22 in FIG. 22) and the first test object (19 in FIG. 22). Show the results of the experiment.

24 to 28, in the case of the conventional non-destructive inspection device, the signal level range when the distance between the sensor array (22 in FIG. 22) and the first test object (19 in FIG. 22) is 18 millimeters (mm) or more. As it becomes very narrow, it can be seen that the display image is also very blurred.

FIG. 29 uses the direct current magnetic field of FIG. 22 for the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention, and the distance between the sensor array (22 of FIG. 22) and the first test object (19 of FIG. 22) Experimental results for 18 millimeters (mm) are shown.

Referring to FIG. 29, the signal level range of the sensor array 22 at the defect site was about 0.23.

Thus, comparing Figs. 26 and 29, under the same conditions of 18 millimeters (mm) apart, the nondestructive testing device of Fig. 13 of the second embodiment of the present invention has a much wider signal level range than the conventional nondestructive testing device. As a result, the displayed image can be seen to be much clearer.

FIG. 30 uses the direct current magnetic field of FIG. 22 for the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention, and the distance between the sensor array (22 of FIG. 22) and the first test object (19 of FIG. 22) Experimental results for 22 millimeters (mm) are shown.

Referring to FIG. 30, the signal level range of the sensor array 22 at the defect site was about 0.05.

Thus, comparing Figs. 27 and 30, under the same conditions of 22 millimeters (mm), the nondestructive testing device of Fig. 13 of the second embodiment of the present invention has a much wider signal level range than the conventional nondestructive testing device. As a result, the displayed image can be seen to be much clearer.

FIG. 31 uses the direct current magnetic field of FIG. 22 for the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention, and the distance between the sensor array (22 of FIG. 22) and the first test object (19 of FIG. 22) Experimental results for 27 millimeters (mm) are shown.

Comparing Figs. 28 and 31, as the non-destructive testing device of Fig. 13 of the second embodiment of the present invention has a slightly wider signal level range in the same condition with a distance of 27 millimeters (mm), compared to the conventional non-destructive testing device. The displayed image is also slightly clearer.

FIG. 32 shows the conventional non-destructive inspection device using the alternating magnetic field of FIG. 23 and having a distance of 1 millimeter (mm) between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23). Show the results of the experiment.

Referring to FIG. 32, the signal level range of the sensor array 22 at the defect site was about 0.5.

FIG. 33 illustrates a conventional non-destructive inspection device using the alternating magnetic field of FIG. 23 and having a distance of 5 millimeters (mm) between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23). Show the results of the experiment.

Referring to FIG. 33, the signal level range of the sensor array 22 at the defect site was about 0.2.

Referring to FIGS. 32 and 33, the distance between the sensor array 22 and the second test object 29 is 5 millimeters (mm) compared to the case of 1 millimeter (mm) (FIG. 32) (FIG. 33). It can be seen that as the signal level range narrows considerably, the display image also blurs.

FIG. 34 illustrates a conventional non-destructive inspection device using the alternating magnetic field of FIG. 23 and having a distance of 10 millimeters (mm) between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23). Show the results of the experiment.

Referring to FIG. 34, the signal level range of the sensor array 22 at the defect site was about 0.02.

Referring to FIGS. 33 and 34, the distance between the sensor array 22 and the second test object 29 is 5 millimeters (mm) (FIG. 33) compared to the case of 10 millimeters (mm) (FIG. 34). It can be seen that as the signal level range narrows considerably, the display image also blurs.

FIG. 35 shows the conventional non-destructive inspection device using the alternating magnetic field of FIG. 23 and having a distance of 18 millimeters (mm) between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23). Show the results of the experiment.

FIG. 36 shows the conventional non-destructive inspection device using the alternating magnetic field of FIG. 23 and having a distance of 22 millimeters (mm) between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23). Show the results of the experiment.

32 to 36, in the case of the conventional non-destructive inspection device, the signal level range when the distance between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23) is 18 millimeters (mm) or more. As it becomes very narrow, it can be seen that the display image is also very blurred.

FIG. 37 uses the alternating magnetic field of FIG. 23 for the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention, and the distance between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23) Experimental results for 18 millimeters (mm) are shown.

Referring to FIG. 37, the signal level range of the sensor array 22 at the defect site was about 0.02.

Thus, comparing Figs. 35 and 37, under the same conditions of 18 millimeters (mm) apart, the nondestructive testing device of Fig. 13 of the second embodiment of the present invention has a much wider signal level range than the conventional nondestructive testing device. As a result, the displayed image can be seen to be much clearer.

FIG. 38 uses the alternating magnetic field of FIG. 23 for the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention, and the distance between the sensor array (22 in FIG. 23) and the second test object (29 in FIG. 23) Experimental results for 22 millimeters (mm) are shown.

Referring to FIG. 38, the signal level range of the sensor array 22 at the defect site was about 0.005.

Thus, comparing Figs. 36 and 38, the nondestructive testing device of Fig. 13 of the second embodiment of the present invention has a slightly wider signal level range than the conventional nondestructive testing device under the same conditions of 22 millimeters (mm) apart. As a result, the displayed image is also slightly clearer.

Thus, comparing FIGS. 35 and 37 and FIGS. 36 and 38, it can be seen that the non-destructive inspection device of FIG. 13 of the second embodiment of the present invention has a much wider separation distance than the conventional non-destructive inspection device.

As described above, according to the non-destructive inspection device according to the present invention, as the ferromagnetic rod is installed between the inspection object and the magnetic sensor, the magnetic field from the inspection object is magnetized while the ferromagnetic rod is magnetized by the magnetic field from the inspection object. To pass on.

Therefore, even if the magnetic sensor is significantly spaced from the inspection object when the inspection object is hot or contaminated, as the signal level range of the magnetic sensor changes little, the performance of the defect display is not lowered.

It can be used to find faults in all objects that respond to direct and alternating magnetic fields.

Claims

A magnetic sensor for generating a magnetic field sensing signal corresponding to the strength of the magnetic field from the inspection object;

A ferromagnetic rod disposed between the inspection object and the magnetic sensor;

A signal processor for converting a magnetic field sensing signal from the magnetic sensor to match a display format; And

And a display unit for displaying the magnetic field detection signal from the signal processor.
The method of claim 1,

Non-destructive inspection device further comprising a magnetic field generating unit for applying an electromagnetic field to the inspection object.
The method of claim 2,

And a signal amplifier for amplifying the magnetic field detection signal from the magnetic sensor and inputting the signal to the signal processor.
The method of claim 2,

Non-destructive inspection device further comprising a case in which the magnetic sensor and the ferromagnetic rod is embedded.
The method of claim 4, wherein

Non-destructive inspection device further comprising a drive unit for moving the case in the scanning direction.
The method of claim 2,

Non-destructive testing device of the cylindrical ferromagnetic rod.
7. The cylindrical ferromagnetic rod of claim 6, wherein

A non-destructive inspection device having a conical end portion facing the inspection object.
The method of claim 2,

The non-destructive testing device of the ferromagnetic rod is a square pillar.
The method of claim 8, wherein in the square columnar ferromagnetic rod,

A non-destructive inspection device having a square pyramid end facing the inspection object.
The method of claim 2,

Non-destructive testing device of the ferromagnetic rod is a triangular prism.
The method of claim 8, wherein in the triangular columnar ferromagnetic rod,

A non-destructive inspection device having a triangular pyramid end facing the inspection object.
The method of claim 2, wherein the ferromagnetic rod,

Non-destructive inspection device having a shape inclined one side of the end facing the inspection object.
The method of claim 2, wherein in the ferromagnetic rod,

A non-destructive inspection device having an end facing the inspection object in a bead.
The method of claim 2, wherein in the ferromagnetic rod,

A non-destructive inspection device having a stepped end facing the inspection object.
The method of claim 2,

Non-destructive inspection device further comprising a cooling unit for cooling the ferromagnetic rod.
The method of claim 2,

Non-destructive inspection device further comprising a blower for blowing wind to the ferromagnetic rod.
A plurality of magnetic sensors for generating magnetic field sensing signals corresponding to the strength of the magnetic field from the test object;

A plurality of ferromagnetic bars installed between the inspection object and the magnetic sensors;

A signal processor converting the magnetic field sensing signals from the magnetic sensors to match a display format; And

And a display unit for displaying the magnetic field detection signals from the signal processor.
The method of claim 17,

Non-destructive inspection device further comprising a magnetic field generating unit for applying an electromagnetic field to the inspection object.
The method of claim 18,

And a signal amplifying unit amplifying the magnetic field sensing signals from the magnetic sensors and inputting the magnetic field sensing signals.
The method of claim 18,

And a case in which the magnetic sensors and the ferromagnetic bars are embedded.
The method of claim 20, wherein the case,

One side member having a first guide groove formed on an inner wall thereof,

Another member having a second guide groove opposed to the first guide groove on an inner wall thereof; and

And a lower member having the magnetic sensors attached to an inner wall thereof.
The method of claim 21, wherein in the case:

The one side member and the other member are fastened in a state where the ferromagnetic rods are inserted into the first guide groove and the second guide groove,

Non-destructive inspection device wherein the lower member is fastened to the bottom surface of the one side member and the other side member.
The method of claim 22, wherein in the lower member of the case,

Non-destructive inspection device provided with auxiliary light sources on both sides of the magnetic sensors.
The method of claim 23, wherein

And a light path member of the auxiliary light sources is inserted between the one side member and the other side member of the case.
The method of claim 18,

And the magnetic sensors are arranged in a straight line in one dimension.
The method of claim 18,

Non-destructive inspection device wherein the ferromagnetic rods are arranged in one plane in two dimensions.
The method of claim 18,

A non-destructive testing device arranged such that one end of one ferromagnetic rod is opposite to one magnetic sensor.
The method of claim 18,

A non-destructive inspection device in which one end of the plurality of ferromagnetic bars is opposed to one magnetic sensor.
The method of claim 18,

A non-destructive inspection device arranged such that an end of one ferromagnetic bar is opposed to a plurality of magnetic sensors.
The method of claim 18,

And the magnetic sensors are arranged in one plane in two dimensions.
The method of claim 18,

And the magnetic sensors are arranged in a three-dimensional curved surface.
The method of claim 18,

Non-destructive inspection device further comprising a cooling unit for cooling the ferromagnetic rods.
The method of claim 18,

Non-destructive inspection device further comprising a blower for blowing air to the ferromagnetic rods.