X-ray inspection device

Abstract

To provide an X-ray inspection device that can prevent X-ray leakage in a configuration where an item is conveyed across two conveyor surfaces.SOLUTION: An X-ray inspection device 1 includes: a conveyance unit 5 that supports and conveys an item G across a first conveyor surface 51a and a second conveyor surface 52a; an inspection unit 15 that inspects the item G by irradiating the item G with X-rays as the item G moves from an inlet opening 4a to an outlet opening 4b; and a shielding unit 40 that is provided at the inlet opening 4a and the outlet opening 4b to shield X-rays that leak from these openings 4a, 4b. The shielding unit 40 includes: a first shielding member 41 that shields the area from upper edges of the openings 4a, 4b to the first conveyor surface 51a and the second conveyor surface 52a; and a second shielding member 42 that shields the area from the upper edges of the openings 4a, 4b to a gap C between a first conveyance section 51 and a second conveyance section 52.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an X-ray inspection apparatus. [Background technology]

[0002] In an X-ray inspection device, an object to be inspected is transported in a horizontal transport direction by a belt conveyor, and X-rays are irradiated when the object to be inspected passes through a gap extending in a direction perpendicular to the transport direction, and detection data of the X-rays that have passed through the object to be inspected is obtained (see, for example, Patent Document 1). As described in Patent Document 1, the belt conveyor is provided inside the housing of the device, and shielding curtains made of flexible X-ray shielding material are attached to the left and right openings of the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-109229 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional device described above, inclined guides and side guides are arranged on both sides of the conveyor belt to irradiate the X-rays obliquely onto the object to be inspected. The inner edges of these guides form a belt holding part whose cross section perpendicular to the conveying direction is approximately V-shaped, so that the ridge of the object to be inspected comes into stable contact with the V-shaped recess of the conveyor belt.

[0005] Incidentally, instead of the above-mentioned guide member, a configuration is also conceivable in which the conveying means itself has two conveying surfaces spaced apart from each other in a direction perpendicular to the conveying direction. The two conveying surfaces extend in the conveying direction, and the article is conveyed in a position straddling the two conveying surfaces. A certain gap exists between the two conveying surfaces. A leakage path of X-rays extending in the conveying direction may be formed near the gap between the two conveying surfaces. In the above-mentioned conventional device, a shielding curtain is attached to the opening of the housing, but it is difficult to prevent leakage of X-rays through the above-mentioned leakage path with such a shielding curtain that is based on a single conveying surface.

[0006] An object of the present invention is to provide an X-ray inspection device capable of preventing leakage of X-rays in a configuration in which an article is transported across two transport surfaces. [Means for solving the problem]

[0007] [1] An X-ray inspection device according to one aspect of the present invention includes a transport unit for transporting an object in a transport direction, the transport unit having a first transport section and a second transport section spaced apart in a horizontal direction perpendicular to the transport direction, and transporting an object straddling a first transport surface of the first transport section and a second transport surface of the second transport section while supporting the object, an inspection unit provided to cover the transport unit and inspecting the object by irradiating the object with X-rays while the object is moving from an entrance opening to an entrance / exit opening, and a shielding unit provided in at least one of the entrance opening and the exit opening and shielding X-rays leaking from the at least one opening. The shielding unit has a first shielding member for shielding from an upper end of at least one opening to the first transport surface and the second transport surface, and a second shielding member for shielding from an upper end of at least one opening to a gap between the first transport section and the second transport section.

[0008] According to the X-ray inspection device of [1], a shielding unit is provided at least one of the entrance opening and the exit opening of the inspection unit. A first shielding member of the shielding unit shields from the upper end of the opening to the first conveying surface and the second conveying surface, thereby preventing leakage of X-rays through the space above these conveying surfaces. In addition, a second shielding member of the shielding unit shields from the upper end of the opening to the gap between the first conveying section and the second conveying section. This prevents leakage of X-rays through the gap. Therefore, in a configuration in which an article is conveyed across two conveying surfaces, leakage of X-rays can be prevented.

[0009] [2] In the X-ray inspection device of [1] above, the second shielding member may be made of a plate-like member, and both ends of the second shielding member in the width direction corresponding to the horizontal direction may be formed with curved ends rounded around an axis extending in the up-down direction. For example, even when a belt or the like of at least one of the first transport section and the second transport section comes into contact with the second shielding member, the belt or the like comes into contact with the curved ends. This reduces contact resistance, and protects movable parts such as the belt.

[0010] [3] In the X-ray inspection device of [1] or [2] above, the second shielding member may be made of metal. In this case, even if the second shielding member comes into sliding contact with the belt of at least one of the first transport section and the second transport section, the second shielding member is less worn. Therefore, the second shielding member is protected.

[0011] [4] In any one of the X-ray inspection devices [1] to [3] above, the transport unit may have a pair of frames arranged side by side across an area through which X-rays pass from the X-ray irradiation unit to the X-ray detection unit, and a connecting member may be attached to the pair of frames to connect a pair of outer ends located at the outer ends in the width direction corresponding to the horizontal direction. According to this configuration, the pair of frames are connected, thereby increasing the rigidity of the entire transport unit. Effect of the Invention

[0012] According to the present invention, leakage of X-rays can be prevented in a configuration in which an article is transported across two transport surfaces. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of an X-ray inspection apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the conveying unit in FIG. 1 taken along a plane perpendicular to the conveying direction. [Diagram 3] FIG. 3 is a perspective view of a connecting member attached to a housing of the inspection unit and a frame of the transport unit. [Figure 4] FIG. 4 is a diagram showing the positional relationship between the connecting member and the frame as viewed from below. [Diagram 5] FIG. 5 is a view of a shielding unit provided in at least one opening of the inspection unit, as viewed from the transport direction. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional plan view of a second shielding member of the shielding unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted.

[0015] 1, the X-ray inspection device 1 includes an apparatus body 2, support legs 3, and a transport unit 5. The support legs 3 support the apparatus body 2. The apparatus body 2 has a housing 9 made of a material capable of blocking electromagnetic waves such as X-rays. The housing 9 includes, for example, an upper part 9a having a display operation unit 8 provided on the front surface, a back part 9b extending in the vertical direction, and a lower part 9c protruding forward from the back part 9b.

[0016] The X-ray inspection device 1 includes an inspection unit 15 incorporated in an apparatus body 2. The inspection unit 15 has an inspection chamber 4 provided at approximately the center in the height direction of the apparatus body 2. The inspection chamber 4 is provided with, for example, a shielding box (not shown). The inspection unit 15 has an X-ray irradiation unit 6 and an X-ray detection unit 7 housed in a housing 9 of the apparatus body 2. The X-ray irradiation unit 6 is disposed in an upper part 9a of the housing 9, and the X-ray detection unit 7 is disposed in a lower part 9c of the housing 9. The inspection unit 15 further includes a control unit 10 provided, for example, in the upper part 9a of the housing 9.

[0017] When viewed from the upstream side in the transport direction A, the first wall 91 of the upper part 9a, the second wall 92 of the back part 9b, and the third wall 93 of the lower part 9c form a U-shape that opens forward. The inspection chamber 4 is a substantially rectangular parallelepiped space surrounded by these walls. A rectangular entrance opening 4a is formed at the upstream end of the inspection chamber 4 in the transport direction A. A rectangular exit opening 4b is formed at the downstream end of the inspection chamber 4 in the transport direction A. The shape and size of the entrance opening 4a are equal to the shape and size of the exit opening 4b. The front of the inspection chamber 4 is covered by a shielding cover (not shown) that is opened and closed during maintenance, for example.

[0018] The transport unit 5 transports an article G (see FIG. 2) in a transport direction A. The transport unit 5 is installed so as to penetrate the inspection chamber 4 in the transport direction A. In other words, the inspection unit 15 is provided so as to cover the transport unit 5.

[0019] The X-ray inspection device 1 generates an X-ray transmission image of the object G while transporting the object G by the transport unit 5, and performs inspection of the object G (for example, inspection of the number of items stored, inspection of foreign matter contamination, inspection of missing items, inspection of cracks and chips, etc.) based on the X-ray transmission image. The transport unit 5 has an input section 20 arranged on the upstream side in the transport direction A, and an output section 30 arranged on the downstream side in the transport direction A. The object G before inspection is carried into the inspection room 4 by the input section 20. The object G after inspection is carried out from the inspection room 4 by the output section 30. The object G determined to be defective by the X-ray inspection device 1 is sorted out of the production line by a sorting device (not shown) arranged downstream of the output section 30. The object G determined to be non-defective by the X-ray inspection device 1 passes through the sorting device as is.

[0020] The X-ray irradiator 6 irradiates the object G transported by the transport unit 5 with X-rays (electromagnetic waves). The X-ray irradiator 6 has, for example, an X-ray tube that emits X-rays, and a collimator that spreads the X-rays emitted from the X-ray tube in a fan shape in a plane perpendicular to the transport direction A. The X-ray detector 7 detects the X-rays irradiated by the X-ray irradiator 6 and transmitted through the object G. The X-ray detector 7 is configured as, for example, a line sensor. Specifically, the X-ray detector 7 has a plurality of photodiodes that are arranged one-dimensionally along a horizontal direction perpendicular to the transport direction A, and a scintillator that is arranged on the X-ray entrance side of each photodiode. In this case, in the X-ray detector 7, the X-rays incident on the scintillator are converted into light, and the light incident on each photodiode is converted into an electrical signal.

[0021] The display operation unit 8 is provided on the upper part 9a of the housing 9 and faces forward. The display operation unit 8 displays various information (i.e., notifies the operator of the operating state) and accepts input of various conditions. The display operation unit 8 is, for example, a liquid crystal display, and displays an operation screen as a touch panel. In this case, the operator can input various conditions via the display operation unit 8. The display operation unit 8 notifies of various abnormalities in the X-ray inspection device 1. A notification light 11, which also functions as a notification unit, is provided on the upper part 9a of the housing 9.

[0022] The control unit 10 is disposed in the device body 2. The control unit 10 controls the operation of each part of the X-ray inspection device 1. The control unit 10 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. A signal output from the X-ray detection unit 7 and A / D converted is input to the control unit 10. The control unit 10 generates an X-ray transmission image of the article G based on the signal output from the X-ray detection unit 7, and functions as an inspection unit that inspects the article G based on the X-ray transmission image.

[0023] Next, the transport unit 5 will be described in detail with reference to FIGS. 1 to 4. FIG. 2 shows a cross section of the loading section 20 as viewed from the downstream side of the transport direction A. As shown in FIGS. 1 and 2, the transport unit 5 has a first transport section 51 and a second transport section 52 that are arranged apart from each other in a horizontal direction (left-right direction in FIG. 2) perpendicular to the transport direction A. The first transport section 51 is arranged, for example, on the rear side (close to the second wall section 92), and the second transport section 52 is arranged, for example, on the front side (front side of the inspection room 4). The transport unit 5 transports an article G straddling the first transport surface 51a of the first transport section 51 and the second transport surface 52a of the second transport section 52 while supporting it. That is, the article G has a diameter larger than the gap C between the first transport surface 51a and the second transport surface 52a. The article G is supported by the first transport surface 51a and the second transport surface 52a while being positioned above the gap C.

[0024] In the transport unit 5 of this embodiment, for example, the first transport section 51 and the second transport section 52 are both inclined. In the transport unit 5, the horizontal direction perpendicular to the transport direction A is defined as the "width direction". The gap C is formed in the center of the width direction of the transport unit 5. The gap C having a constant or approximately constant width extends in the transport direction A. As shown in FIG. 2, the first transport section 51 includes a first transport belt B1 forming a first transport surface 51a. The second transport section 52 includes a second transport belt B2 forming a second transport surface 52a. The first transport belt B1 and the second transport belt B2 are each provided across the above-mentioned carry-in section 20 and carry-out section 30. Meanwhile, the first transport section 51 has a first frame 21 included in the carry-in section 20 and a first frame 31 included in the carry-out section 30 (see FIG. 4). The second transport section 52 has a second frame 22 included in the load section 20 and a second frame 32 included in the unload section 30 (see FIG. 4).

[0025] As shown in FIG. 4, the first frame 21 and the first frame 31 are spaced apart in the conveying direction A. The second frame 22 and the second frame 32 are spaced apart in the conveying direction A. The position of the interval Y1 between the first frames 21 and 31 and the position of the interval Y2 between the second frames 22 and 32 are aligned in the conveying direction A. An X-ray passage area X from the X-ray irradiation unit 6 to the X-ray detection unit 7 is formed so as to pass through these intervals Y1 and Y2. However, one first conveyor belt B1 extends beyond the interval Y1. One second conveyor belt B2 extends beyond the interval Y2. In FIG. 4, in order to make the arrangement of each frame easier to see, only the back rail portions B1a and B2a of the first conveyor belt B1 and the second conveyor belt B2 are illustrated.

[0026] 2, the endless first transport belt B1 includes an upper portion that moves in the transport direction A and forms a first transport surface 51a, and a lower portion that moves in the opposite direction to the transport direction A. The endless second transport belt B2 includes an upper portion that moves in the transport direction A and forms a second transport surface 52a, and a lower portion that moves in the opposite direction to the transport direction A. Unless otherwise specified, the following description of each of the first transport belt B1 and the second transport belt B2 will be about the upper portions.

[0027] The first frame 21 of the first conveying section 51 supports and guides the first conveying belt B1. The second frame 22 of the second conveying section 52 supports and guides the second conveying belt B2. The first frame 21 includes a groove 21e that receives the back rail B1a and positions the first conveying belt B1. The second frame 22 includes a groove 22e that receives the back rail B2a and positions the second conveying belt B2. The grooves 21e and 22e each extend in the conveying direction A. The back rails B1a and B2a fit into the grooves 21e and 22e to prevent the first conveying belt B1 and the second conveying belt B2 from meandering. The first frame 31 and the second frame 32 also have the same shape and arrangement as shown in FIG. 2. The cross-sectional shape of each of these frames is not particularly limited, and various known shapes may be adopted. Each frame may have notches or the like formed at multiple locations in the conveying direction A.

[0028] The inner end B1b of the first conveyor belt B1 is lower than the outer end B1c. The inner end B2b of the second conveyor belt B2 is lower than the outer end B2c. Similarly, the inner end 21b of the first frame 21 is lower than the outer end 21c. The inner end 22b of the second frame 22 is lower than the outer end 22c. The first conveyor section 51 and the second conveyor section 52 having the above configuration constitute a V-shaped conveyor. The first conveyor section 51 and the second conveyor section 52 are likely to support an article G that is easy to roll (such as a circular or rounded article). The V-shape of the first conveyor surface 51a and the second conveyor surface 52a shown in FIG. 2 is maintained over the entire conveyor direction A. The inclination angle (angle with respect to the horizontal plane) of the first conveyor section 51 and the second conveyor section 52 (the first conveyor surface 51a and the second conveyor surface 52a) may be set appropriately. In this specification, the terms "inner end" and "outer end" relating to the frames (conveyor frames) of the first transport section 51 and the second transport section 52 are based on the positions in the width direction.

[0029] As shown in Fig. 4, the passing area X formed between the first frames 21, 31 and between the second frames 22, 32 extends along direction D when viewed from below. Direction D is a direction intersecting both the conveying direction A in the conveying unit 5 and the opposing direction (the direction perpendicular to the paper surface of Fig. 4) in which the X-ray irradiator 6 and the X-ray detector 7 face each other. In this embodiment, the conveying direction A and direction D are horizontal directions, and the opposing direction between the X-ray irradiator 6 and the X-ray detector 7 is the up-down direction (vertical direction). Direction D is the width direction mentioned above.

[0030] As shown in FIG. 3 and FIG. 4, the pair of first frames 21, 31 and the pair of second frames 22, 32 are arranged side by side with the X-ray passing area X between them. A connecting member 60 is attached to the transport unit 5 to connect the first frames 21, 31 and to connect the second frames 22, 32. The connecting member 60 has a pair of base surface portions 61 fixed on the third wall portion 93 of the housing 9, a pair of side plate portions 62 erected at the outer end in the width direction of the base surface portion 61, a pair of lower support portions 63 provided at the inner end in the width direction of the base surface portion 61, and a pair of upper pressing plate portions 64 provided at the upper ends of the side plate portions 62. The base surface portion 61 and the lower support portions 63 are formed with a transverse opening 66 that extends in the width direction and has a rectangular shape when viewed from below so as not to affect the X-rays in the passing area X. The X-ray irradiation unit 6 is arranged within the range of the transverse opening 66 when viewed from the lower surface side of the base surface portion 61.

[0031] The pair of side plate portions 62 are located outside the first conveying portion 51 and the second conveying portion 52 in the width direction. One (rear) side plate portion 62 is fixed to the outer end portion 21c of the first frame 21 and the outer end portion 31c of the first frame 31 with a screw or the like, thereby connecting the outer ends 21c, 31c. The other (front) side plate portion 62 is fixed to the outer end portion 22c of the second frame 22 and the outer end portion 32c of the second frame 32 with a screw or the like, thereby connecting the outer ends 22c, 32c. One (rear) lower support portion 63 supports the inner end portion 21b of the first frame 21 and the inner end portion 31b of the first frame 31. The other (rear) lower support portion 63 supports the inner end portion 22b of the second frame 22 and the inner end portion 32b of the second frame 32. In FIG. 3, in order to make it easier to understand the structure of the connecting member 60, illustration of the configuration related to the transport unit 5, such as a conveyor frame, is omitted.

[0032] A rectangular opening 62e continuous with the transverse opening 66 is formed at the lower part of the pair of side plate parts 62. The length of the opening 62e in the conveying direction A is sufficiently larger than the passing area X of the X-ray. A cylindrical air nozzle 69 extending in the width direction is attached to the upstream side of the opening 62e in the conveying direction A. The air nozzle 69 is disposed upstream of the passing area X so as not to affect the X-ray in the passing area X. The air nozzle 69 has a plurality of injection holes 69a directed slightly downward downstream. The air nozzle 69 is connected to an air source of compressed air via an air pipe (both are omitted in the figure). As a result, air is injected from the air nozzle 69 toward the vicinity of the opening 93e formed in the third wall part 93 (toward the downstream side) (the upper surface of the housing 9).

[0033] The pair of base surface portions 61 and the pair of side plate portions 62 are connected by a mountain-shaped central lower shielding plate 67 and a pair of triangular lateral lower shielding plates 68 arranged at the upstream end of the connecting member 60. The connecting member 60 is an integral structure made of a metal material (e.g., stainless steel) capable of shielding against X-rays. In addition, a holding mechanism 120 that holds the inner end portion 21b of the first frame 21 and the inner end portion 22b of the second frame 22 is provided on the upstream side of the connecting member 60 in the transport direction A. A holding mechanism 130 that holds the inner end portion 31b of the first frame 31 and the inner end portion 32b of the second frame 32 is provided on the downstream side of the connecting member 60.

[0034] In this way, the connecting member 60 connects the loading section 20 and the unloading section 30 in the conveying direction A and holds them together. Also, the first conveying section 51 and the second conveying section 52 are connected and held together in the width direction. The connecting member 60 does not have any member that crosses the passing area X. No part of the connecting member 60 is captured by the X-ray detection unit 7 during X-ray photography. In this way, the connecting member 60 connects and supports a pair of conveyors separated in the width direction. In particular, the side plate portion 62 and the lower support portion 63 reliably support the V-shaped conveyor.

[0035] 2 and 4, the back rail portion B1a of the first conveyor belt B1 is disposed closer to the outer end B1c (at a position closer to the outer end B1c). The back rail portion B2a of the second conveyor belt B2 is disposed closer to the outer end B2c (at a position closer to the outer end B2c). As a result, the back rail portions B1a and B2a are disposed outside the passing area X so as not to affect the X-rays in the passing area X. The back rail portions B1a and B2a are not captured by the X-ray detection unit 7 during X-ray photography.

[0036] Each of the first conveying section 51 and the second conveying section 52 has a known configuration such as a motor, a pulley, a timing belt, a driving roller, and a driven roller (all of which are omitted in the figure). The first conveying section 51 and the second conveying section 52 run the first conveying belt B1 and the second conveying belt B2 at the same moving speed. As a result, the conveying unit 5 conveys the object G at that running speed. The moving speed (each conveying speed) of the first conveying belt B1 and the second conveying belt B2 can be adjusted, for example, manually. The object G is conveyed on the first conveying belt B1 and the second conveying belt B2 (near the inner ends B1b, B2b and above the inner ends B1b, B2b). In this way, the posture of the object G conveyed in the valley part of the V-shaped conveyor is unlikely to change. In other words, the object G is unlikely to roll on the conveyor. In addition, if fine foreign matter or the like is attached to the object G, the foreign matter or the like may fall off the object G. The fallen foreign objects fall through the gap C between the V-shaped conveyors.

[0037] 1, the inspection unit 15 inspects the object G by irradiating the object G with X-rays while the object G enters from the entrance opening 4a and travels to the exit opening 4b. In the inspection unit 15, leakage of X-rays to the outside is prevented by a shielding box and various shielding mechanisms described below. The object G before inspection is carried into the inspection room 4 through the entrance opening 4a. The object G after inspection is carried out of the inspection room 4 through the exit opening 4b.

[0038] The X-ray inspection device 1 includes a shielding unit 40 provided at both the entrance opening 4a and the exit opening 4b to shield X-rays leaking from the entrance opening 4a and the exit opening 4b to the outside. In FIG. 1, the pair of shielding units 40 are omitted. The shielding unit 40 will be described in detail with reference to FIGS. 5 to 7. As shown in FIG. 5, the shielding unit 40 includes a holding member 44 extending in the width direction and fixed to the upper portion 9a of the housing 9, a second shielding member 42 arranged in the center in the width direction, a plurality of first shielding members 41 arranged on both sides of the second shielding member 42 in the width direction, and an outer shielding member 46 arranged on the outer side of the first shielding member 41 in the width direction. The first shielding member 41, the second shielding member 42, and the outer shielding member 46 are held by the holding member 44 and hang down. The shielding unit 40 is a shielding curtain installed at at least one of the entrance opening 4a and the exit opening 4b.

[0039] The first shielding members 41 and the pair of outer shielding members 46 are made of a resin material containing tungsten and can shield X-rays. The first shielding members 41 and the outer shielding members 46 are thin and, for example, highly deformable. In the shielding unit 40 arranged on the upstream side, the first shielding members 41 shield from the upper end of the entrance opening 4a to the first conveying surface 51a and the second conveying surface 52a. The lower end of the first shielding member 41 may be slightly in contact with the first conveying surface 51a and the second conveying surface 52a, but may be temporarily separated from the first conveying surface 51a and the second conveying surface 52a depending on the positional fluctuation (waviness) of the first conveying surface 51a and the second conveying surface 52a. The length of the first shielding member 41 may be adjusted to the standard position (height) of the first conveying surface 51a and the second conveying surface 52a. In the shielding unit 40 disposed downstream, the multiple first shielding members 41 shield from the upper end of the outlet opening 4b to the first conveying surface 51a and the second conveying surface 52a. The length of the first shielding members 41 is the same as above.

[0040] The single second shielding member 42 is, for example, a plate-like member capable of shielding X-rays. The second shielding member 42 is, for example, a stainless steel plate having a thickness of about 1 mm to several mm. That is, only the second shielding member 42 located at the center of the shielding curtain is made of metal. The second shielding member 42 does not have deformability (or flexibility). In the shielding unit 40 arranged on the upstream side, the second shielding member 42 shields from the upper end of the entrance opening 4a to the gap C between the first conveying surface 51a and the second conveying surface 52a. The lower end of the second shielding member 42 may terminate near the gap C between the inner end B1b of the first conveying belt B1 and the inner end B2b of the second conveying belt B2, or may extend beyond the gap C to a position slightly below the gap C. The hanging length of the second shielding member 42 hanging from the holding member 44 is longer than the hanging length of any of the first shielding members 41. The lower end 42b of the second shielding member 42 comes into contact with the article G being transported by the transport unit 5.

[0041] At the position of the inlet opening 4a, the inner end 21b of the first frame 21 and the inner end 22b of the second frame 22 are adjacent to each other with a gap equal to or smaller than the gap C between the inner end B1b of the first conveyor belt B1 and the inner end B2b of the second conveyor belt B2. In this case, the width of the lower end 42b of the second shielding member 42 is, for example, slightly smaller than the gap C. At the position of the outlet opening 4b, the inner end 31b of the first frame 31 and the inner end 32b of the second frame 32 are adjacent to each other with a gap equal to or smaller than the gap C between the inner end B1b of the first conveyor belt B1 and the inner end B2b of the second conveyor belt B2. In this case, the width of the lower end 42b of the second shielding member 42 is, for example, slightly smaller than the gap. The width of the lower end 42b of the second shielding member 42 is adjusted to the gap between the frames adjacent in the width direction.

[0042] As shown in FIG. 6, for example, the upper end 42a of the second shielding member 42 is rotatably attached to a shaft portion 42d extending in the width direction. When the article G moves in the conveying direction after the upper end 42a of the second shielding member 42 comes into contact with the article G, the second shielding member 42 is pushed by the article G and swings. After the article G passes under the lower end 42b, the second shielding member 42 returns to the hanging position between the frames. Note that, when a plurality of articles G are conveyed continuously, the second shielding member 42 may abut against the following article G (adjacent on the upstream side) without returning to the hanging position. Even at the swing limit position shown by the virtual line in FIG. 6, the lower end 42b of the second shielding member 42 does not interfere with (does not overlap) the passage area X of the X-ray. When the second shielding member 42 is positioned at the hanging position, the lower end 42b prevents leakage of the X-ray. While the second shielding member 42 is being pushed and swung by the article G, the article G itself prevents leakage of X-rays.

[0043] 7, curved end portions 42f are formed at both ends of the second shielding member 42 in the width direction, the end portions being rounded around an axis extending in the up-down direction. The curved end portions 42f can be formed, for example, by a curling process. The curved end portions 42f may be formed only near the lower end portion 42b. The curved end portions 42f may contact both or either one of the inner end B1b of the first conveyor belt B1 and the inner end B2b of the second conveyor belt B2.

[0044] A pair of outer shielding members 46 located at both ends in the width direction shield the space between the transport unit 5 and the wall portion surrounding the inspection room 4 (the second wall portion 92 or the above-mentioned openable / closable shielding cover, etc.).

[0045] According to the X-ray inspection device 1 of this embodiment, the shielding unit 40 is provided at both the entrance opening 4a and the exit opening 4b of the inspection unit 15. The first shielding member 41 of the shielding unit 40 shields from the upper ends of the entrance opening 4a and the exit opening 4b to the first conveying surface 51a and the second conveying surface 52a, thereby preventing leakage of X-rays through the space on these conveying surfaces. In addition, the second shielding member 42 of the shielding unit 40 shields from the upper ends of the entrance opening 4a and the exit opening 4b to the gap C between the first conveying section 51 and the second conveying section 52. This prevents leakage of X-rays through the gap C. Therefore, in a configuration in which an article G is conveyed across two conveying surfaces, leakage of X-rays can be prevented.

[0046] Even when either the first conveyor belt B1 or the second conveyor belt B2 contacts the second shielding member 42, the belts B1, B2, etc. contact the curved end portion 42f. This reduces contact resistance, and protects the movable parts of the belts B1, B2, etc.

[0047] Since the second shielding member 42 is made of metal, even when the second shielding member 42 comes into sliding contact with the belts B1, B2, etc., the second shielding member 42 is hardly worn down. Therefore, the second shielding member 42 is protected.

[0048] The connecting members 60 connect the first frame 21 and the first frame 31, and the second frame 22 and the second frame 32, so that the rigidity of the entire transport unit 5 is increased.

[0049] Furthermore, the central lower shielding plate 67 and the pair of side lower shielding plates 68 of the connecting member 60 prevent leakage of X-rays through the space below the V-shaped first transport section 51 and second transport section 52.

[0050] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the shielding unit 40 may be provided at only one of the entrance opening 4a and the exit opening 4b. A plurality of shielding units 40 may be provided at both the entrance opening 4a and the exit opening 4b, or at only one of the entrance opening 4a and the exit opening 4b. The double shielding unit 40 enhances the shielding effect of X-rays at the entrance opening 4a or the exit opening 4b.

[0051] The second shielding member 42 may be made of a resin capable of blocking X-rays. In that case, the second shielding member 42 may contain tungsten or the like, similarly to the first shielding member 41. When the second shielding member 42 is highly deformable, the swing mechanism shown in FIG. 6 may be omitted.

[0052] The curved ends 42f may be omitted from both ends of the second shielding member 42 in the width direction.

[0053] The present invention is not limited to a case in which a plurality of first shielding members 41 are arranged in the width direction, but may be such that one is provided on each side of the second shielding member 42, that is, a pair of first shielding members 41 are provided.

[0054] The first conveying section 51 and the second conveying section 52 (the first conveying surface 51a and the second conveying surface 52a) may extend horizontally without being inclined with respect to the horizontal plane. In other words, the first conveying section 51 and the second conveying section 52 may be flat conveyers spaced apart in the width direction instead of V-shaped conveyers. [Explanation of symbols]

[0055] 1...X-ray inspection device, 4...inspection room, 4a...entrance opening, 4b...exit opening, 5...transport unit, 6...X-ray irradiation unit, 7...X-ray detection unit, 9...housing, 10...control unit, 15...inspection unit, 21...first frame (conveyor frame), 22...second frame (conveyor frame), 31...first frame (conveyor frame), 32...second frame (conveyor frame), 40...shielding unit, 41...first shielding member, 42...second shielding member, 51...first transport section, 51a...first transport surface, 52...second transport section, 52a...second transport surface, 60...connecting member, 69...air nozzle, 91...first wall section, 92...second wall section, 93...third wall section, A...transport direction, B1...first transport belt, B2...second transport belt, C...gap, G...item, X...passage area.

Claims

1. a conveying unit that conveys an article in a conveying direction, the conveying unit having a first conveying section and a second conveying section that are arranged spaced apart in a horizontal direction perpendicular to the conveying direction, the conveying unit supporting and conveying an article straddling a first conveying surface of the first conveying section and a second conveying surface of the second conveying section; an inspection unit provided to cover the transport unit and configured to inspect the object by irradiating the object with X-rays while the object is moving from the entrance opening to the exit opening; a shielding unit provided in at least one of the entrance opening and the exit opening and configured to shield the X-rays leaking from the at least one opening, the shielding unit includes a first shielding member that shields from an upper end of the at least one opening to the first conveying surface and the second conveying surface, and a second shielding member that shields from an upper end of the at least one opening to a gap between the first conveying section and the second conveying section. X-ray inspection equipment.

2. the second shielding member is a plate-shaped member, The X-ray inspection apparatus according to claim 1 , wherein both ends of the second shielding member in a width direction corresponding to the horizontal direction are formed with curved ends that are rounded around an axis extending in a vertical direction.

3. The X-ray inspection apparatus according to claim 1 or 2, wherein the second shielding member is made of metal.

4. the transport unit includes a pair of frames arranged side by side across an area through which X-rays pass from an X-ray irradiation unit to an X-ray detection unit; 3. The X-ray inspection apparatus according to claim 1, wherein a connecting member is attached to the pair of frames, the connecting member connecting a pair of outer ends located at outer ends in a width direction corresponding to the horizontal direction.

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