JP2008275451A - X-ray foreign matter detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compatibly achieve compactness and safety with a specific shielding structure capable of shortening the length of a frame, in an X-ray foreign matter detector of oblique irradiation type. <P>SOLUTION: The inside of the frame of the X-ray foreign matter detector is provided with a conveyor 12 for conveying an object to be inspected, an X-ray generator 10 for obliquely radiating X-rays to the object to be inspected in an irradiation plane A crossing the conveyance direction, and an X-ray detector 11 arranged on the opposite side to the X-ray generator with respect to the conveyor. In the frame, a pair of shielding members 30 and 30 are disposed across the irradiation plane in each of both sides of the conveyor in the irradiation plane. X-rays are shielded in the frame, so that the length of the frame in the conveyance direction can be shortened. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an X-ray foreign matter detection apparatus that detects foreign matter by irradiating X-rays from an oblique direction to an object to be inspected that is transported in a shielded housing by a transport means. The present invention relates to an X-ray foreign object detection device that is provided with a shielding structure useful for shortening the size of the housing and that is compact and has high safety.

  The X-ray foreign object detection device described in Patent Document 1 below irradiates an object to be inspected conveyed by a conveyor in a shielded casing with X-rays vertically downward from directly above the conveyor, and below the conveyor. It is an apparatus that detects X-rays with an X-ray detector provided, and thereby detects foreign matter in the inspection object. In this apparatus, a shielding member is provided in the vicinity of the X-ray irradiation unit inside the housing. The shielding member provided in the vicinity of the X-ray irradiation unit in the housing has a structure in which the X-ray irradiation is performed from directly above the conveyor to directly below, so that it contacts the lower conveyor from the upper side of the housing. It is composed of a pair of shielding curtains that are suspended so as to sandwich the X-ray irradiation surface with dimensions that are not. By providing the shielding structure inside the housing, the amount of X-rays leaking to the outside from the openings on both side surfaces of the housing where both ends of the conveyor protrude outside the housing is reduced.

The X-ray foreign object detection apparatus described in Patent Document 2 below is oblique to an object to be inspected conveyed by a conveyor in a shielded casing from an X-ray irradiator provided obliquely above the side of the conveyor in the casing. X-rays are irradiated downward, and X-rays are detected by an X-ray detector provided obliquely below the side of the conveyor, thereby detecting foreign matter in the inspection object. Unlike the X-ray foreign object detection apparatus of Patent Document 1 that irradiates X-rays vertically downward, the X-ray foreign object detection apparatus of Patent Document 2 performs oblique X-ray irradiation for the following reason. That is, when the object to be inspected is a tall article, the sensitivity of foreign matter detection may be insufficient even when X-rays are irradiated from directly above by vertical irradiation, and X-rays are irradiated from the side. In the structure, the inspection accuracy of the bottom of the inspection object may be insufficient. In such a case, it is effective to obliquely irradiate the inspection object with X-rays. Patent Document 2 discloses the principle of such oblique irradiation. However, the structure as an X-ray foreign matter detection device in which an X-ray generator, an X-ray detector, a conveyor and the like are housed in a casing, particularly a specific shielding. The structure is not mentioned.
JP 2004-132747 A JP 2004-317184 A

  In the oblique irradiation type X-ray foreign matter detection apparatus effective for the inspection object, the machine length (length in the transport direction) is short, and there is compactness that can cope with a small installation area, and at the same time, the X-ray shielding property is high, There is a need for an X-ray foreign object detection device having a configuration excellent in safety.

  In general, in an X-ray foreign object detection apparatus that inspects a foreign object by irradiating X-rays while transporting an object to be inspected in the casing, the length of the casing in the transport direction can be shortened in order to shorten the machine length. Although it is considered necessary, in such a structure, the opening on the side surface of the casing through which the conveying means penetrates to the outside approaches the X-ray irradiation position in the casing, so as described above unless any shielding measures are taken. It is difficult to reduce the size of the casing.

  However, in the invention described in Patent Document 2 that discloses the principle of oblique irradiation, when an X-ray generator, an X-ray detector, a conveyor, etc. are stored in a housing with an arrangement / structure for oblique irradiation, In order to set the Captain as short as possible, there was no specific problem awareness (presentation of issues) of what shielding structure would be necessary.

  The present invention solves the above-described problem in concretely realizing the oblique irradiation type X-ray foreign matter detection apparatus as described above, and is effective for oblique inspection objects. In particular, the X-ray foreign object detection device of the present invention is provided with a special shielding structure capable of shortening the machine length (length in the conveying direction) in the housing, and is provided with a compact and highly safe X-ray foreign object detection device. It is aimed.

The X-ray foreign object detection device according to claim 1 is:
A frame that shields X-rays;
A conveying means provided in the frame and configured to convey an inspection object in a predetermined conveying direction;
An X-ray generator that is provided in the frame and that irradiates X-rays in an oblique direction within an irradiation surface that intersects the transport direction with respect to an inspection object transported by the transport means;
An X-ray detector which is provided in the frame and which is arranged on the opposite side of the X-ray generator with respect to the transport means and detects an X-ray transmitted through the inspection object transported by the transport means;
In the frame, at least one side part of the irradiation surface in which the X-ray detector is provided, at least on both sides of the irradiation surface so as to sandwich the irradiation surface. A pair of shielding members;
It is characterized by comprising.

The X-ray foreign matter detection device according to claim 2 is the X-ray foreign matter detection device according to claim 1,
In the frame, a pair of shielding members on both sides of the irradiation surface so as to sandwich the irradiation surface also on the other side portion where the X-ray generator is provided among both side portions of the conveying means in the irradiation surface. Is featured.

The X-ray foreign matter detection device according to claim 3 is the X-ray foreign matter detection device according to claim 2,
The pair of shielding members are arranged above the transport unit at an angle of attack that does not hinder the transport of the inspection object transported by the transport unit.

The X-ray foreign matter detection device according to claim 4 is the X-ray foreign matter detection device according to claim 3,
Openings are formed on the left and right side surfaces of the frame, respectively, and the conveying means is installed so that each part protrudes from each opening, and in each of the openings, an object to be inspected conveyed by the conveying means is provided. A pair of shielding shutters are provided that are arranged at an angle of attack that does not hinder the conveyance, always close each opening, and are opened by the object to be inspected conveyed by the conveyance means.

  According to the X-ray foreign object detection apparatus of claim 1, the X-ray generator is configured to incline in the oblique direction within the irradiation surface intersecting the conveyance direction with respect to the object to be inspected which is conveyed in the housing by the conveyance means. Irradiate the line. An X-ray detector disposed on the opposite side of the X-ray generator with respect to the conveying means detects X-rays that have passed through the object to be detected and detects foreign matter. Here, although scattered X-rays are generated on the X-ray detector side that receives X-rays, at least the X-ray detector side is provided with a pair of shielding members on both sides of the conveying means so as to sandwich the irradiation surface. Therefore, this scattered X-ray can be effectively shielded. Since the casing has such an effective shielding structure, the amount of X-rays reaching the openings on both sides of the casing where both ends of the conveying means protrude outside the casing is reduced as much as possible. Therefore, it is possible to set the size of the housing in the transport direction small.

  According to the X-ray foreign object detection device of the second aspect, the pair of shielding members are further provided on the side of the conveying means on which the X-ray generator is provided so as to sandwich the irradiation surface. Further, the shielding of X-rays in the housing is further ensured, and the size of the housing in the transport direction can be set further smaller.

  According to the X-ray foreign object detection device described in claim 3, the pair of shielding members used for shielding X-rays in the housing does not hinder the operation of the conveying means itself, and the conveying means. It does not hinder the conveyance of the object to be inspected.

  According to the X-ray foreign object detection device described in claim 4, openings are formed on the left and right side surfaces of the frame, respectively, and the conveying means is installed so that each part protrudes from each opening. Since the shielding shutter having the double-spread structure is provided in the openings in a normally closed state, the shielding at these openings is further ensured.

An example of an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view of the X-ray foreign object detection apparatus of the present example in a normal state and when the side cover (side housing 16) is opened, and FIG. 2 is an X-ray of the present example in which the X-ray irradiation ranges are overlapped. FIG. 3 is a right side view of the wire foreign object detection device 1, and FIG. 3 is a plan sectional view of the X-ray foreign material detection device 1 of this example showing the belt 13 of the conveying means 12 (conveyor). It is a principal part perspective view in the housing | casing of the X-ray foreign material detection apparatus of this example which overlapped and showed the irradiation range.

  As shown in FIG. 1, the present apparatus has a box-shaped frame 2 having a shielding structure that is a main body of the apparatus. The frame 2 is erected on the support floor surface by a leg-shaped support portion 6. The support portion 6 of this example is composed of a pair of front support members 7 provided on the left and right sides of the frame 2 and a pair of rear support members 8 provided on the left and right sides of the frame 2, for a total of four. Has been.

  As shown in FIG. 2, the frame 2 of the X-ray foreign object detection device 1 of the present example is an integrally structured casing as a whole in this example, but is composed of two parts, an upper casing 3 and a lower casing 4. ing. The upper housing 3 is provided with a conveyance space S for an inspection object. The conveyance space S communicates the left and right side surfaces of the upper housing 3 and the lower surface is open. Each part of the upper housing 3 surrounding the conveyance space S is referred to as a rear portion 3a, a front portion 3b, and an upper portion 3c with the conveyance space S as a reference.

  A conveyor 12 is attached to the lower housing 4 in order to transport the inspection object in the transport space S. Specifically, as shown in FIG. 1, a pair of substantially triangular support plates 30 are attached to both side surfaces of the lower housing 4 directly below the conveyance space S to support the rollers 31. The belt 13 is wound along the upper and lower surfaces of the lower housing 4 and is circulated and driven by a motor (not shown).

  A side housing 16 (side cover) that covers each opening of the frame 2 is provided at a portion that the conveyor 12 penetrates and protrudes out of the frame 2. The side housing 16 is attached to the inner surface of the pair of side plates 20 and 20 having a double-spread structure that is rotatably attached to the frame 2 via a hinge, and the pair of side plates 20 and 20 to prevent X-ray leakage. 2 sets of four shutters 22 and a detachable top plate 21 covering the upper side of the pair of side plates 20, 20 arranged in parallel to each other. As shown in FIG. The top surface of 12 can be opened.

  In the present embodiment, each shutter 22 is made of, for example, a lead-containing rubber sheet cut into a substantially rectangular shape, and as shown in FIG. 3, one side edge portion has a leaf spring 19 as an elastic member, and a side plate 20. The other side edge that is attached to the inner surface of the lens and is in a cantilever state is positioned downstream in the transport direction in the normal assembly state, and is arranged at an angle of attack that does not hinder the transport of the inspection object. Yes. The pair of shutters 22 and 22 disposed at both sides of the conveyor 12 at the above-mentioned angle of attack always opens the opening of the frame 2 by overlapping each other side edge portion in a cantilever state as shown in FIG. Closed. Since the shutter 22 is attached to the side plate 20 by the leaf spring 19, if the inspection object conveyed by the conveyor 12 comes into contact with the overlapping portion of the pair of shutters 22, 22, the moving force of the inspection object is used. The pair of shutters 22 and 22 are opened, and the object to be inspected can come out of the frame 2 and the side housing 16. The shutter 22 away from the object to be inspected is safe because it quickly returns to the original position by the elastic force of the leaf spring 19 and closes the opening.

  As shown in FIG. 1, an interlock switch 17 is provided on the side surface of the frame 2 as a safety mechanism that enables the X-ray generator 10 to operate. Then, when the side plate 20 and the top plate 21 are assembled into a normal box shape as a normal state as shown in FIG. 1, an operation member (not shown) provided on the top plate 21 turns the interlock switch 17 on. The device is operable and ready for X-ray irradiation.

  Although not shown in detail, there is a gap between the front portion 3b of the upper housing 3 and the lower housing 4, and a freely openable / closable shielding plate (not shown in detail) is provided in this gap. This shielding plate can shield the conveyance space S when the apparatus is operated, and can open a gap between the housings in order to remove the belt 13 of the conveyor 12 to the front of the lower housing 4 during maintenance.

  As shown in FIGS. 2 and 3, in the upper housing 3 of the frame 2, an X-ray generator 10 is accommodated in the upper portion of the front portion 3 b of the transfer space S. The X-ray generator 10 is installed so as to irradiate the X-rays in a plane toward the transport space S that is obliquely below and rearward when viewed from the installation position. In FIG. 2, the hatched triangular area indicates the X-ray irradiation surface A (planar irradiation area). The height of the irradiation surface A on the conveyor 12 is set to be at least larger than the height of the inspection object.

  As shown in FIGS. 2 and 3, an X-ray detector 11 is disposed between the inside of the conveyor 12 in the lower housing 4 of the frame 2 and the rear portion of the transport space S of the upper housing 3. Is provided. The X-ray detector 11 has a sensor group arranged linearly so as to be parallel to the planar X-ray (irradiation surface A) irradiated from the X-ray detector 11, and from the installation position thereof. The X-ray irradiation center line C emitted from the X-ray generator 10 located obliquely above the front of the X-ray generator 10 is installed in an oblique posture so as to be perpendicular to the central portion thereof.

  Therefore, as can be seen from the X-ray irradiation surface A shown in FIG. 2, the X-rays that have passed through the inspection object carried on the belt 13 of the conveyor 12 are transmitted through the conveyor 12 or as they are. The line detector 11 is reached. The sensor group of the X-ray detector 11 outputs a voltage waveform signal proportional to the X-ray dose distribution reached, and this signal is processed by a control circuit (not shown) to determine whether there is a foreign object in the inspection object. Is judged.

  As shown in FIGS. 1 to 3, two covers 25 and 26 are provided on the front side of the frame 2 so as to be openable and closable. If the upper cover 25 is opened, the X-ray generator is provided. 10, and the conveyor 12 can be accessed by opening the lower cover 26.

  Next, as shown in FIGS. 3 and 4, in the frame 2, a pair of shielding members 30 are respectively provided on both sides of the conveyor 12 in the irradiation surface A (that is, both sides in the width direction of the belt 13). Is provided. The shielding member 30 is a substantially rectangular member that is long in the vertical direction, and is made of a material having an X-ray shielding function such as rubber containing lead.

  Each pair of shielding members 30 provided on both sides of the conveyor 12 is arranged so as to sandwich the irradiation surface A as shown in FIG. 3 in a plan view, and is transported in the transport direction of the conveyor 12. It is attached at an angle of attack that does not impede transport of the inspection object. That is, the front end of the shielding member 30 that is closer to the belt 13 than the holding member 31 that holds the base of the shielding member 30 at a position slightly away from the belt 13 and that may be in contact with the object to be inspected. The angle is such that it is located downstream in the conveying direction of the conveyor 12.

  Further, as shown in FIG. 4, the shielding member 30 is disposed above the belt 13 on the upper side of the conveyor 12 in the height direction, and is configured not to interfere with the belt 13. The height is set so as to exceed the height of the object to be inspected, and the upper end is above the upper edge of the X-ray irradiation surface A.

  According to the above configuration, the X-rays emitted from the X-ray generator pass between the pair of shielding members 30 on the X-ray generator side, pass through the inspection object on the conveyor 12, and detect X-rays. Passes between the pair of shielding members 30 on the instrument side and reaches the X-ray detector. Therefore, unnecessary X-rays including scattered X-rays and the like in this inspection region are shielded by these two pairs of shielding members 30 and reduced as much as possible.

  Even if the inspection object conveyed by the conveyor 12 contacts the shielding member 30 in the process of the inspection, the shielding member 30 is set to an angle of attack that allows the contacting inspection object to easily escape as described above. In addition, since the shielding member 30 has elasticity, it does not hinder the conveyance of the inspection object. Therefore, both the inspection of the inspection object on the irradiation surface A and the X-ray shielding at the position are performed with the expected certainty and safety.

  If at least one side of the conveyor 12 where the X-ray detector is provided is provided with shielding members 30 on both sides of the irradiation surface A, X-rays that are likely to generate scattered X-rays when irradiated with X-rays. A sufficient effect can be obtained because the shielding on the detector side is ensured. In this example, since a pair of shielding members 30 are provided on both sides of the conveyor 12, X-rays that can leak out of the frame 2 are generated in the frame 2. Can be shielded more effectively. Therefore, the length (machine length) of the frame 2 in the transport direction by the conveyor 12 can be set small while ensuring sufficient safety.

  Further, in this example, since the side housing having the shutter of the double door structure as described above is provided in the opening portion where the conveyor protrudes from both side surfaces of the frame set short, the X-ray shielding effect is More reliable and safer.

FIG. 1 is a perspective view of the X-ray foreign object detection device of the present example in a normal state and when a side cover (side housing) is opened. FIG. 2 is a right side view of the X-ray foreign object detection device of the present example showing the X-ray irradiation ranges in an overlapping manner. FIG. 3 is a plan sectional view of the X-ray foreign matter detection apparatus of the present example showing the belt of the conveying means (conveyor). FIG. 4 is a perspective view of the main part in the housing of the X-ray foreign object detection device of the present example, showing the X-ray irradiation range in an overlapping manner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... X-ray foreign material detection apparatus 2 ... Frame 3 ... Upper housing | casing 4 ... Lower housing 10 ... X-ray generator 11 ... X-ray detector 12 ... Conveyor as conveyance means 13 ... Belt 16 ... Side housing | casing 20 ... Side plate constituting the side housing 21 ... Top plate constituting the side housing 22 ... Shutter constituting the side housing 30 ... Shielding member 30 S ... Transport space A ... X-ray irradiation surface

Claims (4)

A frame that shields X-rays;
A conveying means provided in the frame and configured to convey an inspection object in a predetermined conveying direction;
An X-ray generator that is provided in the frame and that irradiates X-rays in an oblique direction within an irradiation surface that intersects the transport direction with respect to an inspection object transported by the transport means;
An X-ray detector which is provided in the frame and which is arranged on the opposite side of the X-ray generator with respect to the transport means and detects an X-ray transmitted through the inspection object transported by the transport means;
In the frame, at least one side part of the irradiation surface in which the X-ray detector is provided, at least on both sides of the irradiation surface so as to sandwich the irradiation surface. A pair of shielding members;
An X-ray foreign matter detection apparatus comprising: In the frame, a pair of shielding members on both sides of the irradiation surface so as to sandwich the irradiation surface also on the other side portion where the X-ray generator is provided among both side portions of the conveying means in the irradiation surface. The X-ray foreign object detection device according to claim 1, wherein: The X-ray foreign object detection according to claim 2, wherein the pair of shielding members are disposed above the conveying unit at an angle of attack that does not hinder the conveyance of the inspection object conveyed by the conveying unit. apparatus. Openings are respectively formed on the left and right side surfaces of the frame, and the conveying means is installed so that each end protrudes from each opening. In each opening, an object to be inspected conveyed by the conveying means is provided. 2. A set of two shielding shutters that are arranged at an angle of attack that does not impede conveyance and that always close the openings and are opened by an object to be conveyed conveyed by the conveying means. Item 4. The X-ray foreign matter detection device according to Item 3.

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