JPH0376403B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-destructive inspection device for materials, products, etc., and particularly to a device for non-contact, non-destructive inspection of internal defects in products and parts produced on a continuous production line such as a factory. . In particular, metal plates that are continuously running,
X-rays are irradiated onto rubber sheets, plate glass, etc., and the transmitted
The present invention relates to continuous nondestructive testing methods and scanning for detecting internal defects in materials from lines.

Quality inspection at factories of metal materials and products such as iron plates and pipes, mass-produced metal parts for automobiles and vehicles, ceramic products such as plate glass and ceramic glass, and rubber products such as tires (internal defect inspection, thickness inspection) etc.), non-destructive testing using X-rays is being conducted. X-ray transmission inspection is also used to detect foreign substances mixed in foods and the like.

There are two types of inspection methods using X-rays: the transmission inspection method, in which the transmitted X-ray image is photographed on film, and the fluoroscopic inspection method, in which the transmitted X-ray image is directly viewed using an image intensifier (II) tube. Both have been widely practiced since ancient times.

Among these methods, the transmission inspection method is particularly suitable for precise inspections because it provides clear images;
Since the transmitted X-ray image is once taken on a film, the film must be developed before the results can be obtained, which has the drawback of taking time. On the other hand, although the results of fluoroscopy can be obtained instantly, the images are not clear, making it unsuitable for detailed examinations, and it also has the drawback of not leaving records.

Therefore, it is possible to inspect materials and products that are continuously manufactured on a factory production line with high responsiveness and high precision, and also record the inspection results or convert them into electrical signals and feed them back to the production line. The above-mentioned conventional inspection methods cannot adequately meet the purpose.

In view of these problems, the present invention is a novel test object that continuously non-destructively inspects a continuously moving test object with high responsiveness, and allows the inspection results to be recorded and used for feedback. The purpose of this invention is to provide a compact and simple X-ray non-destructive inspection device.

The non-destructive inspection device of the present invention includes: an X-ray source that irradiates a moving test object with X-rays; a predetermined position near the test object that receives the X-rays transmitted through the test object; an X-ray shielding member having an X-ray exposure slit extending in a direction intersecting the running direction of the object, and movable in a direction intersecting the slit to the predetermined position receiving the X-rays passing through the X-ray exposure slit; a recording body having a layer of stimulable phosphor; a means for moving the recording body in a direction intersecting the slit; excitation light irradiation means for irradiating excitation light onto a portion of the recording medium that has already been exposed to X-rays; a reading means for reading X-ray image information recorded on the recording body; and a reading means disposed downstream of the reading means in the moving direction of the recording body, and applying erasing light to the recording body after emitting the stimulated luminescence light. It is characterized by comprising an erasing means for emitting X-ray energy remaining in the recording medium upon irradiation. Particularly preferably, the stimulable phosphor sheet is run at the same speed as the continuously running test object, and the read signals are displayed on a CRT and monitored, while being permanently recorded on photographic film, magnetic tape, optical disc, etc. It is also used for the purpose of detecting data, and is also sent to a controller or the like as a detection signal for feedback to the manufacturing line. Methods of using these read signals (detection signals) are appropriately selected and combined according to requirements.

The above-mentioned stimulable phosphor sheet is one in which a stimulable phosphor is coated on a sheet-like support, but this sheet is not limited to individual sheets separated one by one. It also includes endless belts such as endless belts. A storage phosphor is a fluorophore that accumulates the energy of radiation when it is irradiated with radiation such as X-rays, and then releases the stored energy as visible light when it is irradiated with excitation light such as visible light or infrared light. It refers to the body, and is disclosed in detail in, for example, Japanese Patent Application Laid-open No. 12429/1983.

In the present invention, the stimulable phosphor sheet is irradiated with X-rays that have passed through the object to be measured through a slit, and then the sheet is irradiated with excitation light and the emitted stimulated luminescence light is detected photoelectrically. This slit is made of a shielding material such as lead foil that does not transmit X-rays.
It extends in a direction perpendicular to the running direction of the object to be tested, or at least in a direction that intersects with the running direction. The stimulated luminescence light is photoelectrically detected by a photoelectric conversion means or the like, and thereby the X-ray image information recorded on the recording medium is read in real time.

The excitation light is irradiated through the slit onto the portion of the sheet exposed to X-rays, preferably in the form of a beam and scanned along the slit, and the stimulated luminescence light is photoelectrically detected as a time-series signal.

The sheet that has been irradiated with excitation light and has emitted stimulated luminescence light is made to emit residual energy by an erasing means for repeated use. This erasing means irradiates the sheet with relatively high-intensity light in the same wavelength range as the excitation light, either uniformly or by two-dimensional scanning. downstream).

The sheet is preferably moved at the same speed and in the same direction as the object to be examined, such that a transmitted X-ray image of the object to be examined is recorded thereon in a 1:1 size ratio;
The moving speed of this sheet does not necessarily have to be the same as that of the object to be inspected. In extreme cases, the sheet may be kept stationary and the object to be examined may be exposed to X-rays while it is moving. At this time, a shutter is installed in the slit to momentarily expose the sheet to X-rays in the form of a slit.
Then, the sheet may be moved by more than the width of the slit, stopped again, and the shutter may be opened again to record the next portion. At this time,
The direction of movement of the sheet and the direction of movement of the object to be examined can also be reversed.

Hereinafter, the apparatus of the present invention will be explained in detail with reference to Examples.

FIG. 1 shows an embodiment in which internal defects in a large number of iron plates 1, 1, . . . are inspected using sheet-like (individual) stimulable phosphor sheets 2, 2, .

A large number of steel plates 1, 1, . A lead foil shielding member 4 is disposed below this, and this shielding member 4 has an exposure slit 4A extending in a direction perpendicular to arrow A. An X-ray source 5 is installed above this slit 4A. A transparent conveyor belt 6 is fed under the shielding member 4 in the direction of arrow B.
A large number of sheet-like stimulable phosphor sheets 2, 2, . . . are placed on top of this and moved in the direction of arrow B.

Downstream from the slit 4A position, the conveyor belt 6
A scanning light thickness system (galvanometer mirror) is placed on the back side of the slit 4A to scan the laser light 7A from the laser light source 7 in the length direction of the slit 4A, and the stimulable phosphor sheet is scanned by the laser light 7A. 6
A detector 9 is installed to collect the stimulated luminescence light emitted by the detector 9 and photoelectrically detect it. This detector 9 has a linear incident end face 9a along the scanning line of the laser beam 7A.
A collection made of a transparent acrylic resin plate has an annular exit end surface 9b along the circular light-receiving surface of the photomultiplier 9B, and guides stimulated luminescence light incident from the entrance end surface 9a to the exit end surface 9b by total reflection. Light device 9A and
It consists of the above-mentioned Photomar 9B (for example, disclosed in Japanese Patent Application Laid-open No. 87970/1983). An erasing light source 11 is provided at a position downstream and away from the position where this laser beam 7A is scanned, with a light shielding plate 10 interposed therebetween. This erasing light source 11 emits light that radiates the X-ray energy remaining in the sheet 2 which has been scanned by the laser beam 7A and radiates the accumulated energy as stimulated luminescence light, and is used for incandescent lamps, fluorescent lamps, xenon flashlights, etc. etc. are used.

The output of Photomaru 9B is Monitor TV 1
2. Information obtained from the X-rays that are transmitted to the recording magnetic tape device 13, defect detection and warning device 14, etc. and transmitted through the object to be inspected is used for display, recording, or warning. The warning device 14 compares, for example, the output from the photo mark 9B with a predetermined reference level,
It is possible to provide a device that emits a warning sound when the X-ray transmittance of the object to be examined 1 becomes above or below a predetermined value. Instead of or together with this warning sound, a defective product rejection signal 14A may be issued to cause a defective product rejection device (not shown) provided separately downstream to eliminate the defective iron plate 1.

According to the apparatus configured as described above, the X-rays 5A transmitted through the object to be examined 1 are irradiated onto the stimulable phosphor sheet 2 in the form of a slit through the exposure slit 4A. Image information of the X-rays that have partially passed through the slit at right angles to the running direction is stored and recorded on the sheet 2. At the same time that the object 1 to be examined moves in the direction of arrow A, the sheet 2 also moves in the direction of arrow B, and while the X-ray transparent part of the object 1 to be examined moves by the width of the slit 4A, the sheet 2 moves through the slit 4A. The X-rays are moved over the width of the sheet 2 so that transmitted X-rays are accumulated on the sheet 2 over the entire surface of the object 1 to be examined. That is, if the object 1 to be examined and the sheet 2 move in the same direction at the same speed, a transmitted X-ray image of equal size is accumulated and recorded on the sheet 2 over the entire area of the object 1 to be examined. Further, for the continuously moving object 1, the sheet 2 may be stopped during X-ray exposure and laser beam irradiation, and intermittent feeding may be performed during which the sheet 2 is fed at high speed. At this time, for example, X-ray exposure and laser beam irradiation are simultaneously performed on the stopped sheet 2, and after the instantaneous X-ray exposure, the sheet 2 is exposed to the width of the slit while the object 1 is fed by the width of the slit. After the object has been moved by the width of the slit, the next exposure can be carried out instantaneously. At this time, for example, a second
As shown in Figure A, a large number of image recording sections 2a each having a slit width are formed in parallel.
In this case, a transmitted image covering the entire area of the object 1 to be inspected is divided into adjacent parts by the slit width and sequentially recorded.

While the sheet 2 is stopped, the laser beam 7A is scanned over the recording portion 2a having the slit width recorded in parallel in this manner, and the stimulated luminescence light emitted from the recording portion 2a is collected by the condenser 9A of the detector 9. The light is focused and a time-series image signal is obtained using Photomar 9B. This image signal contains information regarding internal defects in the object to be inspected 1 in the form of a high or low output level.
Internal defects can be detected from this image signal.

Of course, the transmitted X-ray image of the object to be examined 1 can be displayed on the monitor television 12 as it is.
It also becomes possible to visually detect internal defects.

After the detection, the sheet 2 is irradiated with light from the erasing light source 11 downstream of the detection section (laser light irradiation section), and the X-ray energy remaining inside is released and recycled into a reusable state. . Light shielding plate 1
0 is for preventing this erasing light from entering the condenser 9A and causing noise.

According to the embodiment described above, it is possible to continuously inspect the internal defects of the object 1 by X-ray transmission while the object 1 is being continuously moved. Moreover, the responsiveness of the detection is also extremely high since the detection results can be obtained while the object is being carried out.

In the above embodiment, when the sheet 2 is moved continuously, the traveling speed of the sheet 2 is made equal to the traveling speed of the object 1 to be examined, and when X-rays are continuously irradiated, the sheet 2 is The transmitted image is stored and recorded as it is, but in this case, unless the width of the slit 4A is made extremely small, the recording resolution will decrease, which will cause a practical problem. If the width of the slit is to be increased to a certain extent, it is necessary to provide a shutter in the slit or to provide a means for instantaneously generating X-rays on the X-ray source side so that X-rays can be irradiated instantaneously.
At this time, if the slit exposed areas (recording areas 2a) recorded on the sheet 2 are too close to each other, there is a risk that the area where recording was completed in the previous exposure will be affected by the next exposure, so each recording area 2a must be recorded at some intervals.

Furthermore, when scanning the sheet 2 with the laser beam 7A while the sheet 2 is continuously running, if the scanning direction is perpendicular to the running direction of the sheet 2, the scanning locus on the sheet 2 will be as shown by the chain line in FIG. 2B. Become oblique to. In FIG. 2B, a region 2b indicated by a solid line is a recording portion subjected to slit exposure.

Next, FIG. 3 shows an example of an inspection device that uses stimulable phosphor sheets connected in the form of an endless belt to measure the thickness of a rolled steel plate and feed back the measurement results to the rolling roller. explain.

The iron plate 2 is rolled by a pair of rolling rollers 21A and 21B.
1 is rolled and sent in the direction of arrow A. A shielding member 22 made of lead foil having a slit 22A is disposed below this, and an endless belt 23 made of a stimulable phosphor sheet is placed under it with four rollers 24A, 24B, 2
It is suspended by 4C and 24D and driven in the same direction B as the iron plate 21. A scanning mirror 26 is arranged below the slit 22A to scan the laser beam 25A from the laser light source 25 along the slit 22A, and the stimulated luminescence light emitted from the endless belt 23 scanned by the laser beam 25A is scanned. A condenser 27 that condenses light is disposed with its entrance end surface 27A adjacent to the scanning line. This condenser 27 is the same as the condenser 9A in FIG. 1, and its exit end face is opposed to the light receiving surface of the photomal 28.

A large number of erasing lamps 29 are arranged at positions downstream of the endless belt 23 exposure and laser scanning section. The output of the photomal 28 is input to a plate thickness calculator 30, where the thickness of the iron plate 21 is calculated from the output of the photomal, and this output is input to a controller 31 that controls the interval between the rolling rollers 21A and 21B. , and is further input to a detection unit 32 that detects internal defects. The output of the detection unit 32 is sent to a controller such as a thick material.

According to the above embodiment, since the stimulable phosphor sheet is formed on the endless level plate 23, repeated use is automatically performed, and the entire device becomes compact, which is advantageous in practice. Furthermore, since the inspection output is fed back to the rolling rolls, it is possible to perform automatic control so that an appropriate rolling thickness is always obtained.

As is clear from the above description, according to the apparatus of the present invention, X-ray image information is recorded on a recording medium having a layer of a stimulable phosphor, and immediately after that, the X-ray image information is recorded by the same apparatus. Since the X-ray image information is read, the object to be examined can be scanned within an extremely short time, and the entire system for recording, reading, and erasing X-ray image information can be made compact and simple. Furthermore, this also makes it easier to continuously inspect continuously moving test objects, especially web-shaped objects, and non-contact, non-destructive inspection becomes possible with high responsiveness, making it possible for industrial The value above is great.
Furthermore, this method can provide much higher resolution than the conventional II visual inspection method.

In addition, in the above method, when high-energy X-rays must be used, such as when the object to be examined is a thick iron plate, the absorption of X-rays by the stimulable phosphor sheet decreases, and the In some cases, it may become impossible to store and record relevant information. At this time, it is also possible to use a method in which a metal foil is superimposed on the object to be inspected, and secondary electrons are generated there, and the electrons are recorded on a stimulable phosphor sheet.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the apparatus of the present invention, and FIGS. 2A and 2B are stimulable phosphor sheets on which an X-ray transmission image of an object to be examined is recorded by the apparatus of the present invention. FIG. 3 is a schematic diagram showing another embodiment of the apparatus for carrying out the method of the present invention. 1, 21... Test object, 4, 22... Shielding member, 2, 23... Storage phosphor sheet, 7, 25
...Laser light source, 9A, 27...Concentrator, 9B,
28... Photomaru, 11, 29... Erasing light source,
12... Monitor television, 13... Magnetic tape device, 14, 32... Defect detector, 21A, 21B
...Rolling roller, 30...Plate thickness calculator, 31...
Rolling roller controller.

Claims (1)

[Claims] 1. An X-ray source that irradiates a moving test object with X-rays, which is installed at a predetermined position close to the test object to receive the X-rays transmitted through the test object, and an X-ray shielding member having an X-ray exposure slit extending in a direction intersecting the traveling direction; an X-ray shielding member provided movably in a direction intersecting the slit at the predetermined position receiving the X-rays passing through the X-ray exposure slit; In addition, a recording body having a layer of stimulable phosphor, a means for moving this recording body in a direction intersecting the slit, and a recording body disposed downstream of the predetermined position in the direction of movement of the recording body and being exposed to X-rays. Excitation light irradiation means for irradiating excitation light onto a portion of the recording medium that has already been exposed to X-rays; photoelectrically detecting stimulated luminescence light emitted from the portion of the recording medium that has been irradiated with the excitation light; a reading means for reading X-ray image information recorded on the recording body; and a reading means disposed downstream of the reading means in the moving direction of the recording body, and configured to irradiate the recording body with erasing light after emitting the stimulated luminescence light. A non-destructive inspection device comprising erasing means for emitting X-ray energy remaining in the recording medium. 2. The non-destructive inspection apparatus according to claim 1, wherein the means for moving the recording body moves the recording body in the same direction as the object to be inspected. 3. The non-destructive method according to claim 1 or 2, wherein the excitation light irradiation means includes a scanning optical system that scans the recording medium with excitation light in the form of a beam. Inspection equipment.