Electron beam irradiation device

Abstract

The present invention provides an electron beam irradiation device that can suppress rusting of magnetic shielding members. [Solution] The electron beam irradiation apparatus 10 comprises a shielding wall 33 having a through hole 34, an accelerator chamber 31 and an irradiation chamber 32 separated from each other by the shielding wall 33, an accelerator Ea housed in the accelerator chamber 31, a scanner 40 housed in the irradiation chamber 32, a connecting pipe 35 inserted through the through hole 34 and connecting the accelerator Ea and the scanner 40, a magnetic shielding member 36 covering the periphery of the connecting pipe 35, a partition 50 provided in the irradiation chamber 32, a shield housing section S1 which is a space partitioned from the space in the irradiation chamber 32 by the partition 50 and houses the magnetic shielding member 36, and a purge air supply section 60 which supplies purge air into the shield housing section S1.

Description

Technical Field

[0001] The present invention relates to an electron beam irradiation apparatus.

Background Art

[0002] An electron beam irradiation apparatus is a device that irradiates a workpiece with an electron beam. Electron beam irradiation apparatuses are used for purposes such as improving the properties of the material of the workpiece, adding functions, and sterilizing. For example, the electron beam irradiation apparatus described in Patent Document 1 includes an accelerator chamber that houses an accelerator and an irradiation chamber that houses a scanner. The accelerator chamber and the irradiation chamber are partitioned by a shielding wall having a through-hole. The accelerator and the scanner are connected to each other by a connecting pipe passed through the through-hole of the shielding wall. The electron beam accelerated by the accelerator enters the scanner through the connecting pipe. Then, by scanning the electron beam in the scanner, it is possible to irradiate the desired range of the workpiece with the electron beam.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electron beam irradiation apparatus as described above, in order to magnetically shield the connecting pipe through which the electron beam passes inside, it is preferable to cover the periphery of the connecting pipe inserted through the through-hole of the shielding wall with a magnetic shielding member. However, in the irradiation chamber, since ozone is generated by the irradiation of the electron beam, there is a risk that the magnetic shielding member located in the through-hole will be rusted by the ozone.

Means for Solving the Problems

[0005] [1] An electron beam irradiation apparatus that solves the above problems comprises a shielding wall having a through hole, an accelerator room and an irradiation room partitioned from each other by the shielding wall, an accelerator housed in the accelerator room, a scanner housed in the irradiation room, a connecting pipe inserted through the through hole and connecting the accelerator and the scanner, a magnetic shielding member covering the periphery of the connecting pipe, a partition provided in the irradiation room, a shield housing section which is a space partitioned from the space in the irradiation room by the partition and houses the magnetic shielding member, and a purge air supply section which supplies purge air into the shield housing section.

[0006] With this configuration, supplying purge air into the shield housing creates a positive pressure within the shield housing relative to the space in the irradiation chamber separated by the partition. This prevents ozone from entering the shield housing from the irradiation chamber. As a result, it is possible to prevent the magnetic shielding material inside the shield housing from rusting due to ozone.

[0007] [2] In the electron beam irradiation apparatus described in [1] above, the scanner is provided with a housing, and the partition is provided between the housing and the shielding wall. This configuration makes it possible to form a shield housing that is separated from the space inside the irradiation chamber by a partition provided between the scanning device housing and the shielding wall.

[0008] [3] In the electron beam irradiation apparatus described in [2] above, the partition is fixed to the housing, and one end of the partition is in contact with the side surface of the shielding wall facing the irradiation chamber.

[0009] This configuration allows for the partition to effectively separate the space within the irradiation chamber from the shield housing. [4] In the electron beam irradiation apparatus described in [3] above, the housing has a protruding portion that protrudes to the outside of the housing, and the partition portion has a clamping member that is fixed to the protruding portion in a manner that sandwiches the protruding portion.

[0010] With this configuration, the clamping member is fixed so as to sandwich the protruding portion in the scanner housing, making it possible to suitably fix the partition portion to the scanner housing. [5] In the electron beam irradiation apparatus described in any of [1] to [4] above, the purge air supply unit comprises an air supply source for supplying the purge air and an air supply duct connected to the air supply source, wherein the air supply duct extends into the shield housing unit.

[0011] With this configuration, purge air from the air supply source can be supplied into the shield housing through the air supply duct. [6] In the electron beam irradiation apparatus described in [5] above, the air outlet in the air supply duct is located on the outer circumference side of the magnetic shielding member.

[0012] With this configuration, since purge air is released from an air outlet located on the outer periphery of the magnetic shielding member, it is possible to effectively suppress the entry of ozone around the magnetic shielding member. [Effects of the Invention]

[0013] According to the electron beam irradiation device of the present invention, it is possible to suppress rusting of the magnetic shielding member. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic diagram showing the electrical configuration of an electron beam irradiation apparatus in an embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing an enlarged portion of the electron beam irradiation apparatus of the same embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view taken along the line 3-3 in Figure 2. [Figure 4] Figure 4 is a schematic cross-sectional view showing an enlarged portion of the modified electron beam irradiation apparatus. [Modes for carrying out the invention]

[0015] The following describes one embodiment of an electron beam irradiation apparatus with reference to the drawings. Note that, for the sake of clarity, some parts of the structure may be exaggerated or simplified in the drawings. Furthermore, the dimensional ratios of each part may differ from those of the actual apparatus.

[0016] (Electrical configuration of electron beam irradiation device 10) The electron beam irradiation apparatus 10 of this embodiment shown in Figure 1 is a scanning-type electron beam irradiation apparatus. The electron beam irradiation apparatus 10 is equipped with a filament 11 made of, for example, tungsten, which emits thermionic electrons. The filament 11 emits electrons by heating itself based on power supplied from a filament power supply 12. The filament 11 is provided on the upstream end of the accelerating tube 13. The filament 11 is installed at the upper end of the accelerating tube 13. That is, the electron beam irradiation apparatus 10 is equipped with an accelerator Ea in which the filament 11 is integrally attached to the accelerating tube 13. Note that the accelerator Ea may include the accelerating tube 13 and surrounding components (not shown) of the filament 11.

[0017] The accelerating tube 13 has a plurality of accelerating electrodes 14 arranged in parallel along its own tube axis. The accelerating tube 13 is positioned such that its own tube axis is, for example, oriented horizontally. Based on power supplied from the accelerating electrode power supply 15, the accelerating electrodes 14 generate an electric field that focuses the electrons emitted from the filament 11 and accelerates them downstream. In other words, in the accelerating tube 13, the electric field generated by the accelerating electrodes 14 generates an electron stream, i.e., an electron beam Eb, directed downstream along the tube axis. The scanning tube 16 is connected to the downstream end of the accelerating tube 13. The accelerating tube 13 and the scanning tube 16 communicate with each other via an internal space 17, and the electron beam Eb travels from the accelerating tube 13 to the scanning tube 16 within this internal space 17.

[0018] The scanning tube 16 has a shape that expands toward the downstream side. The scanning tube 16 is provided with a scanning coil 18 at its upstream end. The scanning coil 18 deflects the direction of the electron beam Eb generated in the acceleration tube 13, that is, scans the electron beam Eb, based on the energization to itself. At the downstream end of the scanning tube 16, for example, an emission port 19 having a substantially rectangular shape is provided. A substantially rectangular window foil 20 is attached to the emission port 19. The window foil 20 allows the electron beam Eb to pass through while sealing the emission port 19. That is, the internal space 17 spanning the acceleration tube 13 and the scanning tube 16 is configured as a sealed space. The internal space 17 is made into a vacuum state at least during the period when the electron beam Eb is generated, for example, by driving a vacuum pump 21 connected to the scanning tube 16.

[0019] The above-described filament power supply 12, acceleration electrode power supply 15, scanning coil 18, and vacuum pump 21 are controlled by a control device 22. The control device 22 adjusts the output of the electron beam Eb through each power supply 12, 15, controls the scanning of the electron beam Eb through the scanning coil 18, and adjusts the vacuum of the internal space 17 of the acceleration tube 13 and the scanning tube 16 through the vacuum pump 21.

[0020] The electron beam Eb emitted through the window foil 20 attached to the emission port 19 is irradiated onto a workpiece 24 conveyed in the conveyance direction x by, for example, a conveyance device 23, and a predetermined process is performed on the workpiece 24. In this case, the electron beam irradiation device 10 is arranged such that the longitudinal direction of the substantially rectangular emission port 19 faces the conveyance orthogonal direction y of the conveyance device 23, and a predetermined scan of the electron beam Eb including the conveyance direction x and the conveyance orthogonal direction y is performed, and irradiation of a substantially rectangular irradiation area A corresponding to the emission port 19 is performed. As the irradiation effect of the electron beam Eb on the workpiece 24, for example, improvement of the properties of the material, addition of functions, sterilization, etc. can be expected.

[0021] (Device Configuration of Electron Beam Irradiation Device 10) As shown in Figure 2, the electron beam irradiation apparatus 10 comprises an accelerator chamber 31 housing an accelerator Ea, an irradiation chamber 32 housing a scanner 40, and a shielding wall 33 separating the accelerator chamber 31 and the irradiation chamber 32. The scanner 40 is a device that includes at least the scanning tube 16, scanning coil 18, and output port 19 described above. The electron beam Eb emitted from the output port 19 is irradiated onto the workpiece 24 inside the irradiation chamber 32. The shielding wall 33 has a through hole 34 that connects the accelerator chamber 31 and the irradiation chamber 32.

[0022] (Configuration of connecting pipe 35 and magnetic shielding member 36) The electron beam irradiation device 10 includes a connecting tube 35 that connects the accelerator Ea and the scanner 40, and a magnetic shielding member 36 that surrounds the connecting tube 35. The connecting tube 35 and the magnetic shielding member 36 are inserted through a through hole 34 in the shielding wall 33. The downstream connecting end 13a of the accelerating tube 13 is connected to a flange portion 35a provided at the upstream end of the connecting tube 35. The end of the through hole 34 on the accelerator chamber 31 side is hermetically sealed by a sealing member 37. The electron beam Eb accelerated by the accelerator Ea enters the scanner 40 through the connecting tube 35. The sealing member 37 includes a material used for shielding X-rays, such as lead, and a sealing material such as a packing.

[0023] The magnetic shielding member 36 is, for example, cylindrical in shape. The magnetic shielding member 36 is made of a metal material such as a silicon steel plate. The upstream end of the magnetic shielding member 36 is fixed to the flange portion 35a of the connecting pipe 35, for example.

[0024] (Configuration of Scanner 40) The scanner 40 includes a housing 41 that houses, for example, some of the components of the scanner 40. The housing 41 houses, for example, the scanning coil 18 that constitutes the scanner 40 (see Figure 1). That is, the housing 41 is provided at the upstream end of the scanning tube 16.

[0025] As shown in Figure 2, the housing 41 is located on the axial extension of the through hole 34 within the irradiation chamber 32. The housing 41 has a housing body 42 and a projection 43 that protrudes from the housing body 42 to the outside of the housing 41. The housing body 42 has an end face 42a facing the irradiation chamber side surface 33a of the shielding wall 33 that faces the irradiation chamber 32. The projection 43 protrudes from the end face 42a of the housing body 42 along the axis L1 to the connecting pipe 35. The projection 43 is, for example, cylindrical with the axis L1 of the connecting pipe 35 as its center. The projection 43 is either separate from or integral to the housing body 42.

[0026] (Configuration of partition section 50) The electron beam irradiation apparatus 10 is equipped with a partition 50 within the irradiation chamber 32. The partition 50 is provided between the housing 41 of the scanner 40 and the shielding wall 33, forming a shield housing S1 that accommodates the magnetic shielding member 36. The shield housing S1 is a space separated from the space within the irradiation chamber 32 by the partition 50.

[0027] As shown in Figure 3, the partition 50 has a first clamp member 51 and a second clamp member 52 that are fastened and fixed to each other by bolts 53 and nuts 54, sandwiching the protrusion 43 of the housing 41. The first clamp member 51 and the second clamp member 52 each have an arc shape that follows the shape of the outer circumferential surface of the protrusion 43. The first clamp member 51 and the second clamp member 52 are fastened and fixed to each other by bolts 53 and nuts 54 at both ends in the circumferential direction centered on the axis L1 of each. In this way, the first clamp member 51 and the second clamp member 52 are fixed in a manner that sandwiches the protrusion 43 of the housing 41.

[0028] As shown in Figure 2, one end of each of the first clamp member 51 and the second clamp member 52 in the direction of the axis L1 abuts against the irradiation chamber side surface 33a of the shielding wall 33. As a result, within the irradiation chamber 32, the space inside the first clamp member 51 and the second clamp member 52 is separated from the space outside the first clamp member 51 and the second clamp member 52. The space outside the first clamp member 51 and the second clamp member 52 is the space where the workpiece 24 to be irradiated with the electron beam Eb is installed (the source of ozone). The space inside the first clamp member 51 and the second clamp member 52 is in communication with the through hole 34. The shield housing section S1 that houses the magnetic shield member 36 consists of the space inside the through hole 34 and the space inside the first clamp member 51 and the second clamp member 52.

[0029] (Configuration of the purge air supply unit 60) The electron beam irradiation apparatus 10 includes a purge air supply unit 60 that supplies purge air Pa into the shield housing S1. The purge air supply unit 60 includes an air supply source 61 such as a blower and an air supply duct 62 connected to the air supply source 61. The air supply duct 62 includes a branching first branch pipe 63 and a second branch pipe 64. The first branch pipe 63 is inserted inside the first clamp member 51 and the second clamp member 52, i.e., into the shield housing S1, through an insertion hole 55 formed in the first clamp member 51.

[0030] The first branch pipe 63 has an air outlet 65 at its tip from which purge air Pa is released. The air outlet 65 of the first branch pipe 63 extends, for example, into the through hole 34. Furthermore, the air outlet 65 of the first branch pipe 63 is located, for example, on the outer circumference (radially outward) of the magnetic shielding member 36. That is, the air outlet 65 faces the outer surface of the magnetic shielding member 36 in the radial direction centered on axis L1.

[0031] The second branch pipe 64 is inserted inside the housing 41. Purge air Pa supplied from the air supply source 61 is supplied into the shield housing S1 through the first branch pipe 63 of the air supply duct 62, and also into the housing 41 through the second branch pipe 64.

[0032] (Operation of this embodiment) The operation of this embodiment will be described below. In the irradiation chamber 32, ozone is generated when the electron beam Eb emitted from the output port 19 of the scanner 40 irradiates the workpiece 24. In the electron beam irradiation device 10 of this embodiment, the shield housing S1, which houses the magnetic shield member 36, is separated from the space of the irradiation chamber 32 (the space including the ozone source) by a partition 50. Purge air Pa is supplied into the shield housing S1 by a purge air supply unit 60. As a result, the inside of the shield housing S1 is under positive pressure relative to the space inside the irradiation chamber 32 separated by the partition 50, thereby suppressing the entry of ozone from the irradiation chamber 32 into the shield housing S1. Consequently, it is possible to suppress rusting of the magnetic shield member 36 that may occur due to ozone.

[0033] Furthermore, purge air Pa from the air supply source 61 is also supplied to the housing 41 of the scanner 40 through the second branch pipe 64. As a result, the inside of the housing 41 is under positive pressure relative to the space inside the irradiation chamber 32, thereby suppressing the entry of ozone from the irradiation chamber 32 into the housing 41. Consequently, it is possible to suppress rusting of components inside the housing 41 due to ozone.

[0034] (Effects of this embodiment) The effects of this embodiment will be described below. (1) The shield housing section S1, which houses the magnetic shielding member 36, is separated from the space inside the irradiation chamber 32 by a partition section 50. The purge air supply section 60 supplies purge air Pa into the shield housing section S1. With this configuration, the supply of purge air Pa into the shield housing section S1 creates a positive pressure inside the shield housing section S1 relative to the space inside the irradiation chamber 32 separated by the partition section 50. This suppresses the entry of ozone from the irradiation chamber 32 into the shield housing section S1. As a result, it is possible to suppress the corrosion of the magnetic shielding member 36 inside the shield housing section S1 by ozone.

[0035] (2) The partition 50 is provided between the housing 41 of the scanner 40 and the shielding wall 33. With this configuration, the partition 50 provided between the housing 41 of the scanner 40 and the shielding wall 33 makes it possible to form a shield housing S1 that is separated from the space inside the irradiation chamber 32.

[0036] (3) The partition portion 50 is fixed to the housing 41, and one end of the partition portion 50 is in contact with the side surface 33a of the shielding wall 33 that faces the irradiation chamber 32. With this configuration, the partition portion 50 can suitably partition the space inside the irradiation chamber 32 from the shield housing portion S1.

[0037] (4) The housing 41 has a protruding portion 43 that protrudes to the outside of the housing 41. The partition portion 50 has a first clamp member 51 and a second clamp member 52 that are fixed to the protruding portion 43 in a manner that sandwiches the protruding portion 43. With this configuration, the first clamp member 51 and the second clamp member 52 are fixed so as to sandwich the protruding portion 43 in the housing 41 of the scanner 40, making it possible to suitably fix the partition portion 50 to the housing 41 of the scanner 40.

[0038] (5) The purge air supply unit 60 includes an air supply source 61 that supplies purge air Pa and an air supply duct 62 connected to the air supply source 61. The first branch pipe 63 in the air supply duct 62 extends into the shield housing S1. With this configuration, purge air Pa from the air supply source 61 can be supplied into the shield housing S1 through the air supply duct 62.

[0039] (6) The air outlet 65 in the air supply duct 62 is located on the outer periphery side of the magnetic shielding member 36. With this configuration, since purge air Pa is discharged from the air outlet 65 located on the outer periphery side of the magnetic shielding member 36, it is possible to effectively suppress the entry of ozone around the magnetic shielding member 36.

[0040] (Other embodiments) The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0041] The supply air duct 62 in the purge air supply unit 60 of the above embodiment may be modified, for example, as shown in Figure 4. The supply air duct 71 shown in Figure 4 is inserted into the housing 41 and includes a third branch pipe 72 and a fourth branch pipe 73 that branch off inside the housing 41. The tip opening of the third branch pipe 72 is located inside the housing 41. A portion of the purge air Pa supplied from the air supply source 61 is supplied into the housing 41 through the third branch pipe 72.

[0042] The fourth branch pipe 73 passes inside the protrusion 43 of the housing 41 and is led out to the outside of the housing 41 from the upper end surface of the protrusion 43 in the direction of the axis L1. In other words, the fourth branch pipe 73 is inserted into the space inside the first clamp member 51 and the second clamp member 52, i.e., into the shield housing S1. The fourth branch pipe 73 has an air outlet 74 at its tip from which purge air Pa is released. The air outlet 74 of the fourth branch pipe 73 extends, for example, into the through hole 34. Also, the air outlet 74 of the fourth branch pipe 73 is located, for example, on the outer circumference side (radially outward) of the magnetic shield member 36. That is, the air outlet 74 faces the outer circumference surface of the magnetic shield member 36 in the radial direction centered on the axis L1. A portion of the purge air Pa supplied from the air supply source 61 is supplied into the shield housing S1 through the fourth branch pipe 73 of the air supply duct 71. This configuration also provides the same effects and advantages as the above embodiment. Furthermore, in the configuration shown in Figure 4, the air supply duct 71 does not penetrate the partition 50, so it is not necessary to provide an insertion hole 55 in the partition 50 as in the above embodiment.

[0043] In the above embodiments and modified examples of the air supply ducts 62 and 71, the air outlets 65 and 74 of the first branch pipe 63 and the fourth branch pipe 73 may be located inside the partition 50 (first clamp member 51 and second clamp member 52).

[0044] The manner in which the partition portion 50 is fixed to the housing 41 is not limited to the above embodiment and can be appropriately changed depending on the configuration. In the partition portion 50 of the above embodiment, for example, one end of the first clamp member 51 and the second clamp member 52 in the circumferential direction may be connected to each other by a hinge.

[0045] The clamp members in the partition portion 50 of the above embodiment consist of a first clamp member 51 and a second clamp member 52 that sandwich the protruding portion 43 of the housing 41, but other than this, for example, a configuration in which the protruding portion 43 of the housing 41 is sandwiched by a single clamp member may also be used.

[0046] The electron beam irradiation device 10 may separately include a purge air supply unit 60 that supplies purge air Pa into the shield housing S1, and a second purge air supply unit that supplies purge air Pa into the housing 41 of the scanner 40.

[0047] The magnetic shielding member 36 is not limited to the silicon steel sheet mentioned in the above embodiment, but may be formed from a metal material other than silicon steel sheet. The embodiments and modifications disclosed herein are illustrative in all respects, and the present invention is not limited to these examples. That is, the scope of the present invention is indicated by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0048] 10...Electron beam irradiation device 31…Accelerator room 32…Irradiation room 33…shielding wall 33a…Side side of irradiation chamber 34…Through hole 35…Connecting pipe 36…Magnetic shielding material 40... Scanner 41… Housing 43...Protrusion 50... Partition section 51…First clamping member (clamping member) 52…Second clamping member (clamping member) 60... Purge air supply unit 61... Air supply source 62... Air intake duct 65...Air discharge port 71... Air intake duct 74...Air discharge port Ea…accelerator Pa... Purge Air S1...Shield housing

Claims

1. A shielding wall having through holes, The accelerator room and the irradiation room are separated from each other by the aforementioned shielding wall, The accelerator housed in the aforementioned accelerator chamber, The scanning device housed in the irradiation chamber, A connecting pipe is inserted through the through hole and connects the accelerator and the scanner, A magnetic shielding member that covers the periphery of the connecting pipe, A partition provided within the irradiation chamber, The space is separated from the space inside the irradiation chamber by the partition, and comprises a shield housing section that houses the magnetic shielding member, The system includes a purge air supply unit that supplies purge air into the shield housing, Electron beam irradiation equipment.

2. The scanner comprises a housing, The partition is provided between the housing and the shielding wall. The electron beam irradiation apparatus according to claim 1.

3. The partition portion is fixed to the housing, and one end of the partition portion abuts against the side surface of the shielding wall facing the irradiation chamber. The electron beam irradiation apparatus according to claim 2.

4. The housing has a protruding portion that extends outward from the housing, The partition portion has a clamping member that is fixed to the protruding portion in a manner that sandwiches the protruding portion. The electron beam irradiation apparatus according to claim 3.

5. The purge air supply unit comprises an air supply source for supplying the purge air, and an air supply duct connected to the air supply source. The aforementioned air supply duct extends into the shield housing. The electron beam irradiation apparatus according to claim 1.

6. The air outlet in the aforementioned air supply duct is located on the outer periphery side of the magnetic shielding member. The electron beam irradiation apparatus according to claim 5.

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