JP2007003247A - Foreign object detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foreign object detector for detecting even a small foreign object while preventing non-detection of a foreign object owing to an oversight of an inspector in detecting a foreign object such as a needle mixed in an inspecting object such as clothing. <P>SOLUTION: This foreign object detector 1 is equipped with a conveyance means 3 for conveying an inspecting object, X-ray irradiation means 4 and 5 for irradiating the inspecting object on the conveyance means 3 with X rays, a plurality of ionization chamber detectors 6 for measuring X-ray transmissivity when the inspecting object on the conveyance means 3 is irradiated with X rays from the irradiation means 4 and 5, and a determination means for determining whether or not any foreign objects are mixed in the inspecting object from respective measurement values of the plurality of chamber detectors 6 and a previously recorded reference value. The plurality of chamber detectors 6 are disposed on two stages on the opposite side of the irradiation means 4 and 5 with the inspecting object between. If it is determined by the determination means that any foreign object is mixed in the inspecting object, the inspecting object can be returned to the inlet side of the conveyance means 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a foreign matter detection device, and more particularly, to a foreign matter detection device for detecting needles, metal pieces, iron powder and the like mixed in clothes, bags, shoes and the like.

  Conventionally, as an apparatus as described above, an apparatus that irradiates an inspection object such as clothing with X-rays to display a fluoroscopic image on a display and visually detects a foreign object is used. This device, for example, stops an inspection object placed on a belt conveyor, irradiates X-rays and displays a fluoroscopic image on a display, and an inspector senses a portion having an abnormal shape visually. To detect foreign matter.

  As such an apparatus, for example, Patent Document 1 discloses a packaging body in which a gap in a packaging body containing food is filled with a filler in order to efficiently detect pebbles, shells, metal pieces and the like in the food with high sensitivity. Describes a technique for projecting X-rays onto a package containing food to be transported and detecting foreign matter mixed in the food.

  Further, in Patent Document 2, in order to reliably detect foreign matter or the like mixed in the ham, the ham is inserted into the through hole of the accommodating member, the ham is pressed from both sides with a pair of pressing members, and is pressed and penetrated. There is disclosed a technique in which an X-ray transmission image transmitted through an accommodation member, a ham, and a pressing member is captured with a camera by being brought into close contact with a hole, irradiated with X-rays from an X-ray irradiation unit toward the accommodation member.

All of the above foreign object detection devices detect foreign objects by detecting an image of an abnormal shape visually observed by an inspector from images taken by an imaging means. Instead, as shown in FIG. 3, a plurality of ionization chamber detectors 16 are aligned in a row on a lead plate 17 below the belt 13 that transports the inspection object, and X-rays are formed from above the inspection object. Is used to detect the presence or absence of foreign matter by measuring the X-ray transmittance of an inspection object.
JP 2004-101368 A JP-A-5-18911

  However, in an apparatus for detecting foreign matter by capturing an X-ray transmission image with a camera as described in Patent Documents 1 and 2, the inspector always monitors the image and visually inspects the inspection object. Therefore, there is a problem that foreign matter cannot be detected if there is an oversight by the inspector.

  On the other hand, with respect to a device that detects foreign matter by measuring the X-ray transmittance using the ionization chamber detector 16 of FIG. 3, the inspector does not always have to monitor the image. Although it can be avoided, there is a problem in that it is difficult to detect a small foreign object because there is a region where the measurement accuracy decreases between the adjacent ionization chamber detectors 16.

  Therefore, the present invention has been made in view of the problems in the conventional foreign matter detection apparatus described above, and prevents the foreign matter from being undetected due to an oversight by the inspector and can detect even a small foreign matter. An object of the present invention is to provide a foreign object detection device.

  To achieve the above object, the present invention provides a transport means for transporting an inspection object, an X-ray irradiation means for irradiating the inspection object on the transport means with X-rays, and the transport from the X-ray irradiation means. A plurality of ionization chamber detectors for measuring the X-ray transmittance when the inspection object on the means is irradiated with X-rays, the measured values of each of the plurality of ionization chamber detectors, and a prerecorded reference value A foreign substance detection apparatus comprising: a determination means for determining whether or not a foreign substance is mixed in the inspection object, wherein the X-ray irradiation means includes the plurality of ionization chamber detectors sandwiching the inspection object. It is characterized by being arranged in two steps on the opposite side. Here, the ionization chamber detector has an electrode in the center of a cylindrical container made of aluminum or the like having a diameter of several centimeters, and an inert gas or the like as an ionized gas is sealed inside the container. This means that a minute ionization current flows due to electrons and cations generated by the ionization of air due to air, and the current is amplified and displayed in units of dose equivalent rate, and a detector similar to this.

  According to the present invention, since the plurality of ionization chamber detectors are arranged in two stages on the opposite side of the X-ray irradiation unit with the inspection object interposed therebetween, there is no region where the measurement accuracy decreases, and the size is small. Even foreign objects can be reliably detected.

  In the foreign object detection device, when the determination unit determines that a foreign object is mixed in the inspection object, the inspection object can be returned to the entrance side of the transportation unit. Thereby, it is possible to reliably collect the inspection object mixed with foreign matters without shifting to the next process.

  When it is determined by the determination means that a foreign object is mixed in the inspection object, a foreign object mixing position display means for indicating a foreign object mixing part of the inspection object is provided. By indicating the foreign matter mixed portion by the foreign matter mixed position display means, the foreign matter can be easily found and taken out.

  The foreign matter mixing position display means includes a swingable spotlight light source, and can irradiate the spotlight from the spotlight light source to the foreign matter mixed portion of the inspection object. Further, the transport means may be a belt conveyor, the X-ray irradiation means may be disposed above the belt of the belt conveyor, and a plurality of ionization chamber detectors may be disposed below the belt in two stages.

As described above, according to the present invention, it is possible to provide a foreign object detection device that can prevent non-detection of a foreign object due to an oversight of an inspector and can detect even a small foreign object.

  FIG. 1 shows an embodiment of a foreign object detection device according to the present invention. The foreign object detection device 1 transports a test object and a main body 2 having openings on both sides through which the test object can pass. A belt conveyor 3 as a transportation means, an X-ray source 4 for irradiating the inspection object with X-rays, a shutter and diaphragm 5 for irradiating or blocking the X-rays on the inspection object, and X-rays on the inspection object The ionization chamber detector 6 for measuring the X-ray transmittance when irradiated, the measured value of the ionization chamber detector 6 and the reference value recorded in advance are compared, and foreign matter is mixed in the inspection object. A personal computer (PC) as a determination means (not shown) for determining whether or not there is a spotlight 7 as a foreign matter mixing position display means.

  The main body 2 is installed on the floor so as to cover the central portion of the belt conveyor 3, and the belt conveyor 3, the X-ray source 4, the ionization chamber detector 6 and the like are fixed to the main body 2.

  The belt conveyor 3 is configured in an endless manner, and an inspection object is placed on the belt 3a and moves in the direction of arrow A in FIG. The belt conveyor 3 drives the belt conveyor 3 so that when a foreign object is detected in the inspection object, the inspection object can be returned to the entrance side of the main body 2 (left side of FIG. 1A). The motor 8 is configured to be operable in the forward and reverse directions.

  The X-ray source 4 is attached above the belt conveyor 3 and irradiates the inspection object with fluorescent X-rays via a shutter and a diaphragm 5. The range of fluorescent X-ray irradiation can be adjusted by the diaphragm 5, and thereby the size of the detectable foreign matter can be adjusted.

  The ionization chamber detectors 6 are provided below the belt 3a of the belt conveyor 3, and a plurality of ionization chamber detectors 6 are arranged in two stages in the vertical direction as shown in FIG. By arranging the ionization chamber detectors 6 in two stages, it is possible to eliminate a gap generated between adjacent ionization chamber detectors 6 when arranged in one stage. As a result, there is no region where the measurement accuracy decreases, and even a small foreign object can be reliably detected.

  In the PC, the X-ray transmittance as a reference value is recorded in advance for each assumed foreign material, and by comparison with the measured value calculated based on the current value detected by the ionization chamber detector 6, It is determined whether foreign matter is mixed in the inspection object. When it is determined that foreign matter is mixed, a command is issued to return the inspection object to the entrance side of the main body 2.

  As shown in FIG. 1C, the spotlight 7 is configured to be able to turn in a plane perpendicular to the belt traveling direction of the belt conveyor 3, and foreign matter is mixed into the inspection object by the PC. When the determination is made, a foreign matter mixed portion of the inspection object is instructed.

  Next, the operation of the foreign object detection apparatus 1 having the above configuration will be described taking as an example the case where the inspection object is clothes and a stainless needle as a foreign object is detected.

  When the belt conveyor 3 is operated and the clothes are placed on the belt 3 a of the belt conveyor 3, the clothes move in the main body 2. The clothes receive X-rays from the X-ray source 4 while moving, and each of the ionization chamber detectors 6 measures the X-ray transmittance. More specifically, when clothes are passing over the ionization chamber detector 6, X-rays that are continuously emitted are blocked, so the ionization chamber detector 6 shows the difference in the X-ray transmittance of the clothes as a current value. After sensing and converting this current value into a voltage, it is further converted into digital data by an AD converter and transmitted to a PC.

  The data relating to the X-ray transmittance transmitted to the PC is compared with the reference value of the X-ray transmittance relating to stainless steel recorded in advance in the PC, and the presence / absence of stainless steel foreign matter (such as a needle) is determined. When it is determined that foreign material made of stainless steel is mixed, the clothes are retracted, and the portion where the foreign material is mixed stops at a predetermined position near the entrance of the main body 2. Further, in response to an instruction from the PC, the spotlight 7 turns to instruct a foreign matter contamination portion of the clothes.

  In the above embodiment, the inspection object is clothes, and the foreign material is stainless steel as an example, but clothes, bags, shoes, etc. other than clothes can be inspection objects, By changing the X-ray transmittance recorded on the PC, iron needles, iron powder, and other metal pieces mixed in these can be detected.

It is a figure which shows one Embodiment of the foreign material detection apparatus concerning this invention, Comprising: (a) is a front view, (b) is an upper surface, (c) is a side view. FIG. 2 is a layout view of an ionization chamber detector of the foreign object detection device of FIG. 1, wherein (a) is a front view and (b) is a plan view. It is a layout view showing an example of an ionization chamber detector of a conventional foreign object detection device, where (a) is a front view and (b) is a plan view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foreign object detection device 2 Main body 3 Belt conveyor 3a Belt 4 X-ray source 5 Shutter (and aperture)
6 Ionization chamber detector 7 Spotlight 8 Motor 9 Lead plate

Claims (5)

Transport means for transporting the inspection object, X-ray irradiation means for irradiating the inspection object on the transport means with X-rays, and X-rays from the X-ray irradiation means to the inspection object on the transport means A plurality of ionization chamber detectors for measuring the X-ray transmittance when irradiated, and the measured values of the plurality of ionization chamber detectors and the reference value recorded in advance, foreign matter is mixed in the inspection object. In the foreign object detection device comprising a determination means for determining whether or not
The foreign substance detection device, wherein the plurality of ionization chamber detectors are arranged in two stages on the opposite side of the X-ray irradiation means with the inspection object interposed therebetween.   2. The foreign object according to claim 1, wherein when the determination unit determines that a foreign object is mixed in the inspection object, the inspection object is returned to the entrance side of the transportation unit. Detection device.   3. A foreign matter contamination position display means for indicating a foreign matter contamination portion of the inspection object when the determination means determines that a foreign matter is mixed in the inspection object. The foreign matter detection device described in 1.   The said foreign substance mixing position display means is provided with the spotlight light source which can be rock | fluctuated, and irradiates a spotlight to the foreign substance mixing part of the said test target object from this spotlight light source. The foreign matter detection device described.   The transport means is a belt conveyor, wherein the X-ray irradiation means is arranged above the belt of the belt conveyor, and a plurality of ionization chamber detectors are arranged below the belt in two stages. The foreign object detection device according to claim 1.

Images