JP2000214300A - Electron beam sterilization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam sterilization apparatus which utilizes the irradiation with an electron beam, which facilitates the simplification of the structure of a conveyance part installed inside a radiation shielding tunnel, removal of bacteria sticking to a conveyor, a guide roller or the like, and the control of hygiene controlled. SOLUTION: This electron-beam sterilization apparatus 50 is provided with a radiation shielding tunnel 16 which has a nearly circular passage is provided, an object to be irradiated conveyor which is installed along a curved passage, and an electron-beam irradiation chamber 17 which is installed in the halfway part of the passage of the radiation shielding tunnel 16. A radiation which is generated due to the irradiation with an electron beam inside the electron- beam irradiation chamber is reflected inside the curved passage inside the shielding tunnel so as to change its direction, and it is scattered and attenuated. A leakage radiation from the entrance of the shielding tunnel 16 is attenuated to a tolerance level or lower. An opening and shutting door by which the passage is opened is installed at least in a part of the shielding tunnel 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for sterilizing mainly hollow containers such as food (beverage) containers and medical containers by irradiating an electron beam, and more particularly to an apparatus for repeatedly beam-scanning a three-dimensional thin hollow container with an electron beam. The present invention relates to an electron beam sterilizer that irradiates and sterilizes a container.

[0002]

2. Description of the Related Art Devices for sterilizing the entire surface of food containers and the like by electron beam irradiation are currently being researched and developed in various fields.
A simple electron beam sterilizer that can be installed inline in a food or beverage filling and packaging line has not yet been put into practical use.

[0003] In addition, since radiation is generated from the electron beam irradiation device, the radiation is covered by a shielding wall so that the radiation does not leak. It is common to employ a method of scattering and attenuating the light to below a reference value. Furthermore, for example, in an in-line sterilization system for beverage containers such as PET bottles, an inlet and an outlet opening for taking the container in and out are always required, and
It has been experimentally found that in order to sterilize the entire surface of a three-dimensional hollow container in-line, an electron beam of at least a medium energy range is required. In general, three or more reflection changes are required to attenuate below the reference value.

Therefore, the present inventor examined a simple electron beam sterilizer shown in FIGS. 10 to 11 as a comparative technique of the present invention as a simple electron beam sterilizer which can be installed in-line in a filling and packaging line for foods and beverages. (Unknown) FIG. 10 is a plan view of a comparative technique when shielding radiation generated when a container is sterilized by electron beam irradiation using a general maze structure. FIG. 11 is a cross-sectional view showing a state in which the container is transported in a maze surrounded by the transport unit shielding wall in FIG.

[0005] First, referring to FIG.
A case where an electron beam sterilizer for sterilizing a T container or the like is configured as an in-line type will be described. In FIG. 10, reference numeral 100 denotes a shielding tunnel formed by continuously connecting a step-shaped transport part radiation shielding wall 4 or a U-shaped irradiation room radiation shielding wall 2.
A deflecting guide roller 102 is disposed in each of the bent portions of the rectangular passage 101 formed in the tunnel 100, and the conveying conveyor 3 inserted from the entrance 9 side of the passage 101 by the guide roller 102 is rotated by 90 °. Alternatively, it is configured to be sent out from the exit 10 side of the passage 101 while making a 180 ° inflection. An electron beam irradiator 1 is interposed at the midpoint of the passage of the shielding tunnel 100, and a PET container 8 placed on the conveyor 3 passes through the electron beam irradiator 1 to a predetermined position. It is configured to perform sterilization.

That is, the PET container 8 is transported from the tunnel entrance 9 to the electron beam irradiation chamber 5 through the passage 101 by the maze-shaped conveyor 3, and is irradiated and sterilized by the electron beam irradiation device 1 with the electron beam. After that, it is carried to the tunnel exit 10 by the maze-shaped conveyor 3 and transferred to the next step. Here, the radiation generated from the electron beam irradiation apparatus 1 is emitted from the tunnel entrance 9 or the exit 10 side while being reflected and changed (referred to as refraction for convenience) through the exit side passage and the entrance side passage.

That is, on the entrance 9 side, the path 1: 6a, path 2: 6b, path 3: 6c, and path 4: 6d in the tunnel passage 101 are attenuated below the allowable reference value by at least three refractions and scatterings. The scattered radiation is radiated from the entrance 9 as the entrance side scattered radiation. Similarly, the exit 10 side is also scattered radiation on the exit side via the path 1: 7a, the path 2: 7b, the path 3: 7c, and the path 4: 7d. From the outlet 10.

[0008]

The sterilization capacity required for a sterilizer for a food container or the like is generally at least one part per million. In addition to sterilizing the container, a structure in which the sterilizer itself does not easily become a contamination source, and a structure in which the sanitary control of the device when the sterilizer is contaminated is easy are essential.

On the other hand, in the comparative technique having a general maze structure shown in FIGS. 10 and 11, a curved conveyor or the like is used as a container conveying device. Since it is necessary to make a total of six bent portions, three at the supply side to the electron beam irradiation device 1 and three at the discharge side from the electron beam irradiation device 1, the deflection guide roller 102 provided in the movable portion and inside is required. This increases the complexity of the structure, necessitates lubrication and the like, and the conveyor 3 requires a return portion for bending by 90 ° or 180 °. There is a drawback that bacteria easily adhere to the parts, and it becomes extremely difficult to remove the bacteria adhered and to perform sanitary control.

[0010] In addition, such a sterilizing apparatus is installed in a clean room of a very high level in order to prevent invasion of bacteria from the outside. Disadvantages are that the sterilization system cannot be configured or that the sterilization system is very expensive.

An object of the present invention is to provide an electron beam sterilizer which solves the above-mentioned problem in a sterilizer using electron beam irradiation. Another object of the present invention is to simplify the structure of the transfer part provided in the radiation shielding tunnel, minimize the extension distance of the transfer conveyor, and minimize the adhesion of bacteria to transfer parts such as conveyors and guide rollers. It is another object of the present invention to provide an electron beam sterilizer that can easily remove the adhered bacteria and easily perform sanitary control even when the bacteria adhere.

Still another object of the present invention is to reduce the amount of radiation leaked from the entrance and exit of the radiation shielding tunnel to an allowable level or less without unnecessarily increasing the size of the conveyor line, thereby reducing the size of the clean room. It is an object of the present invention to provide an electron beam sterilizer capable of achieving the following.

[0013]

According to the first aspect of the present invention,
In an electron beam sterilizer for irradiating an electron beam on a hollow three-dimensional object such as a food container, a beverage container, or a medical container to achieve an intended purpose such as sterilization, a substantially concave curve is formed in the middle of the passage. A radiation shielding tunnel having a bulging curved path having no path, a conveyor for irradiating an object along the curved path, and an electron beam irradiator provided in the path of the radiation shielding tunnel A room, and scattered and attenuated the radiation generated by the electron beam irradiation in the electron beam irradiation room while changing the reflection in the curved passage in the shielding tunnel,
Leakage radiation from the entrance and exit of the shield tunnel is attenuated below an allowable level.

In this case, the curved passage in the radiation shielding tunnel may be a perfect circle, an ellipse, an ellipse, a parabola, a hyperbola, a part of these curves, or a part of these curves. And a straight line, it is possible to easily form a bulging curved passage having substantially no concave curved path in the middle of the passage.

According to this invention, since the conveyor passage formed in the shielding tunnel is a bulging curved passage having substantially no concave curved road, a return passage is provided in the middle of the passage. It is not necessary to provide a deflecting guide roller or the like, and it is not necessary to form a bent portion in the tunnel passage. The structure can be simplified, and lubrication and the like become unnecessary. Also, the transport conveyor does not need a return portion for bending by 90 ° or 180 °, so that the total extension distance of the movable portion can be shortened. The risk of bacteria being attached to parts and the like is reduced.

According to the first and second aspects of the present invention, the shape of the tunnel passage is a bulging curved passage, while the radiation generated from the electron beam irradiation chamber is a straight line. Even if the path distance of the path is short, reflection redirection can be performed a plurality of times, in other words, refraction in multiple paths is possible. Can be attenuated below an acceptable level. This makes it possible to reduce the size of the clean room without unnecessarily increasing the conveyor conveyance line.

In this case, it is preferable that the electron beam irradiation chamber is provided at a midpoint where the distance between the upstream side and the downstream side in the transport direction of the radiation shielding tunnel is substantially equal.

According to the present invention, the conveyor is formed endless so as to communicate from an exit opening to an entrance opening of the shielding tunnel, and a conveyor driving means is provided at a communication portion outside the tunnel. It is better to connect to

Therefore, according to the present invention, since the driving means is outside the tunnel, maintenance is easy and the structure inside the tunnel can be simplified.

The invention according to claim 5 is characterized in that at least a part of the shielding tunnel is provided with an opening / closing door that opens the passage.

According to this invention, when the hollow container as the irradiation object falls down or becomes clogged on the conveyor in the radiation shielding tunnel, the container jamming or the like occurring in the radiation shielding tunnel occurs. By opening the door, it is possible to easily cope with the problem. In this case, the opening and closing door is preferably provided on the outer peripheral side of the shielding tunnel.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. However, the types, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples, unless otherwise specified.

FIGS. 1 to 9 show an electron beam sterilizer for sterilizing PET bottles and other beverage containers according to an embodiment of the present invention in-line. FIG. 1 is a plan view showing the entire structure, and FIG. 1 is a sectional view taken along the line AA, and FIG.
FIG. 4 is a side view showing the arrangement of the electron beam irradiation device and the container in the electron beam irradiation chamber, and FIG. 5 is a front view of FIG. 4 showing a layout in the electron beam irradiation chamber. 6 is a cross-sectional view of a main part showing an opening and closing structure of the opening and closing door of the radiation shielding tunnel. FIG. 7 is a plan view showing an entire structure and an opening and closing driving structure of the opening and closing door of the radiation shielding tunnel. FIG. 9 is an operation diagram showing an attenuation path, and FIG. 9 is an enlarged operation diagram showing an irradiation state of an electron beam to a container.

In FIG. 1, reference numeral 16 denotes a ring-shaped radiation shielding tunnel.
And a passage 51 around which the PET container 8 placed on the conveyor 18 circulates, and the upper and lower sides of the tunnel 16 in the figure are cut into a fan shape of about 60 °, and the left opening thereof is connected to the entrance 5.
2. The right opening is the outlet 53.

The conveyor 18 is formed of a mesh conveyor so that the electron beam can easily pass therethrough. The conveyor 18 is wrapped around an endless ring so as to communicate between the entrance 52 and the exit 53. The drive gear 12 is provided at a central position (immediately below in the figure) between the entrance portion 52 and the exit portion 53 exposed from the tunnel 16, and the supply side star wheel 60 is provided on the left side of the entrance portion 52, and further on the right side thereof. The discharge-side star wheels 61 are disposed on the outlet 53 side of the discharge rollers.

On the opposite side (lower side) of the conveyor side of the supply side star wheel 60, a linear supply side feed screw 13 is provided, and on the opposite side (lower side) of the conveyor side of the discharge side star wheel 61. Are each provided with a linear discharge-side feed screw 14. An electron beam irradiation room 17 surrounded by the irradiation room shielding wall 2 is provided at the midpoint of the radiation shielding tunnel 16, and the shielding tunnel 16 inserted in the irradiation room 17 is connected to the midpoint thereof. The electron beam irradiating device 1 is disposed at the divided opening interval position at a predetermined interval at the position, and the container 8 conveyed by the conveyor 18 can be directly irradiated with the electron beam. .

A part of the outer peripheral wall of the radiation shielding tunnel 16 has a door structure which can be opened and closed so that jamming of the container 8 generated in the radiation shielding tunnel 16 can be easily dealt with. This configuration will be described later.

Next, the relationship between the electron beam sterilizer 50 of the present embodiment and the preceding and subsequent steps will be described with reference to FIG.
Container 8 conveyed from the previous process of electron beam sterilizer 50
Are transported and placed on the container conveyor 18 at a predetermined pitch interval via the supply side feed screw 13 and the supply side star wheel 60. The container 8 is sent to the electron beam irradiation chamber 17 through the passage 51 of the radiation shielding tunnel (supply side) 16a by the conveyor 18 and irradiated with the electron beam by the electron beam irradiation device 1 in the irradiation chamber 17 and then sterilized. Then, it passes through the radiation shielding tunnel (discharge side) 16b, and is transferred to the next step at a predetermined pitch interval via the discharge side star wheel 61 and the discharge side feed screw 14.

Next, a specific transport structure of the container 8 in the electronic sterilizer 50 of the present invention will be described with reference to FIGS.
The transfer conveyor 18 has a ring-shaped transfer gear 15 mounted on the inner peripheral side thereof. The inner circumferential side of the transfer gear 15 has a flat plate ring shape, and the flat plate portion has a bearing as shown in FIG. A tooth profile is engraved on the outer peripheral side, and the tooth profile is formed in the space below the conveyor 18 between the entrance 52 and the exit 53 exposed from the tunnel 16. Mesh with the drive gear 12 located at the center of
The drive gear 12 has a structure in which the lower side of the inner peripheral wall of the passage 51 is revolved around a bearing member 19 fitted in a ring-shaped concave portion.

As shown in FIG. 2, FIG. 4 and FIG.
0 is erected, and a ring-shaped guide ring 25 is attached to the upper end of the column 20, and the guide ring 25 has a neck at a position corresponding to the pitch interval of the container 8 as shown in FIGS. Guides 21 are attached, and the neck guides 21 hold the necks of the respective containers 8 so as to maintain a predetermined pitch interval for prevention of lodging during conveyance of the conveyor 18.

Next, the structure of the electron beam irradiation apparatus 1 will be described with reference to FIG.
It will be described based on. In the drawing, reference numeral 43 denotes a pair of scanning magnets for performing beam scanning; 23, a flat diverging electron beam irradiation horn having an irradiation window 23a formed in a front surface in a substantially U-shape according to a container shape; A DC voltage power supply (not shown) is connected to deflection magnets disposed on the left and right sides of the shape irradiation window 23a and for applying lines of magnetic force to the vacuum space in the horn. Numeral 8 denotes a container (PET bottle), which is sequentially conveyed to an irradiation position while standing on a mesh-shaped conveying conveyor 18. The reason why the conveyer 18 is formed in a mesh shape is to facilitate irradiation of an electron beam from the reflector 24 disposed on the lower side.

A reflection plate 24 is arranged at a position facing the bottom of the container 8 below the mesh-shaped conveyor 18 located on the side opposite to the electron beam irradiation window 23a. The reflection plate 24 is made of a metal having a large atomic number such as gold (plating) or tungsten, and is set so that effective reflection of the electron beam 42 can be expected. The shape of the reflecting surface of the reflecting plate 42 may be set slightly in the form of an arm so that the electron beam is focused on the bottom of the container 8, or may be formed in a flat plate shape as in the present embodiment. May be.

The deflecting magnets 44A and 44B are connected to the irradiation horn 2
3 is provided on both sides of the irradiation window 23a.
A pair of the deflecting magnets 44A and 44B are not arranged at the symmetrical positions with respect to the front and rear sides (the deflecting magnets 44A and 44B on the far side in the figure are not visible). The scanning electron beam oscillating in a fan shape by the electron beam irradiation horn 23 needs to take a larger deflection angle toward the center (in the direction in which the PET bottle 8 is located) as the deflection angle increases, in other words, as the beam moves outward. There is. Therefore, the deflecting magnets 44A and 44B are arranged such that, within a magnetic field having a uniform magnetic flux density, the distance through which the magnetic field passes is varied. It is preferable to employ a method of combining the two, and a method of combining the two. Such a system is disclosed in Japanese Patent Application No.
-64812 and the like.

Next, an electron beam irradiation structure of the container 8 in the electron beam irradiation chamber 17 will be described with reference to FIGS. As shown in FIG. 5, a radiation shielding tunnel (supply side) 16a and a radiation shielding tunnel (discharge side) 16b, which are radiation shielding structures of the container 8, are provided in the electron beam irradiation room 1 surrounded by the irradiation room shielding wall 2.
The electron beam irradiation horn 2 penetrates to the center of 7
3 and the electron beam irradiation device 1 are sandwiched therebetween. The electron beam irradiation horn 23 is attached to the electron beam irradiation device 1 so as to straddle the container 8 by a U-shaped irradiation window 23a as shown in FIGS. A reflection plate 24 is attached below the electron beam irradiation horn 23 via the transport conveyor 18, and irradiates the bottom of the container 8 with reflected electron beams 45c and 46c (see FIG. 9) from the electron beam irradiation horn 23. It has become.

Referring to FIGS. 6 and 7, the radiation shielding tunnel 1 will be described.
6 An opening / closing / driving structure provided on the outer peripheral side will be described. In FIG. 6, the outer peripheral shielding wall of the ring-shaped radiation shielding tunnel 16 is an opening / closing door 26 that is cut in a stepwise manner along the diagonal of the corner of the shielding wall from the upper and lower ends of the passage 51,
The opening / closing door 26 has an arm 27 attached to its lower end.
And a rotary shaft 31 which is integral with the rotary shaft 31 and
The hinged member 8 pivotally supports the opening / closing door 26 so as to be rotatable around the hinge, so that the inside of the passage 51 can be opened from the outer periphery of the shielding wall.

As shown in FIG. 7, the door 26 has an entrance 52
The radiation shielding tunnel (supply side) 16a from the electron beam irradiation chamber 17 to the electron beam irradiation chamber 17 and the radiation shielding tunnel (discharge side) 16b from the electron beam irradiation chamber 17 to the outlet 53 are equally divided into three equal parts, respectively. The rotating shafts 31 of the opening and closing doors 26 are connected via bevel gears 32, and each of the shafts 31 is rotated in synchronization by an opening and closing door driving device 30 provided at one end thereof, and is divided into three equal parts. Each of the doors 26 is configured to be opened individually or synchronously on the supply side and the discharge side.

Next, regarding the operation and effect of this embodiment, first, the operation and effect of radiation attenuation in the radiation shielding tunnel 16 are described.
The effect will be described with reference to FIG. Radiation generated from the electron beam irradiation horn 23 of the electron beam irradiation device 1 is such that radiation oscillating in a straight line is generated in the inner periphery of the passage 51 because the passage 51 in the radiation shielding tunnel 16a has a narrow arc shape on the supply side. The light is refracted while being sequentially reflected and changed on the surface, and guided toward the entrance 52. That is, pass 1: 40a, pass 2: 40b,
The light is refracted while passing through the longest path of the path 3: 40c, is attenuated below the allowable dose as a path 4: 40d, and is radiated to the outside through the opening of the supply-side entrance 52. Similarly, the radiation-shielded tunnel 16b is also on the discharge side Via the longest route of path 1: 41a, path 2: 41b, path 3: 41c,
Pass 4: The light is attenuated below the allowable dose as 41d, and is emitted from the opening of the discharge side outlet 53.

Therefore, compared with the complicated method of securing attenuation of radiation with a plurality of bent structures, such as the maze method of the comparative technique shown in FIGS. 10 to 11, the radiation can be attenuated with a simple and small structure. Is possible.

Next, the operation and effect of transporting and sterilizing the container 8 will be described with reference to FIGS. 1 to 5 and FIG. As shown in FIGS. 1 to 3, the pitch of the containers 8 sent from the preceding process of the present apparatus is determined by the feed-side feed screw 13 and transferred to the supply-side star wheel 60. Since the neck guide 21 attached to the transport gear 15 via the support 20 and the guide ring 25 and the supply side starwheel 60 are configured to rotate in synchronization with each other, the container 8 is provided with the supply side starwheel 60. When the container 8 is transferred onto the conveyor 18, the container 8 is transferred while supporting the neck portion of the container 8 in the neck guide 21 in a loosely fitted state.

Transport conveyor 18 and neck guide 21
Is mounted on the transport gear 15, and as the transport gear 15 is driven to rotate by the drive gear 12, the PET containers 8 placed at a predetermined pitch on the conveyor 18 are moved to the electron beam irradiation chamber 17. Be transported.

As shown in FIG. 9, an electron beam 42 from the electron beam irradiation device 1 is scanned by a scanning magnet 43 in a direction perpendicular to the traveling direction of the PET container 8. Scanned electron beam 4
2 irradiates the PET container 8 from above with the beam A: 45a and the beam α: 46a in a range where the scanning angle is small,
When the scanning angle increases, the beam is bent by the deflecting magnet 44, and the beam B: 45b and the beam β: 46b make PET.
The body of the container 8 is irradiated. Also, P
The bottom of the ET container 8 is irradiated with a reflected electron beam C: 45c and a beam γ: 46c from the reflection plate 24. In this way, the PET container 8 is sterilized by electron beam irradiation only by passing through the electron beam irradiation horn 23.

Since the transport gear 15 is continuously rotated by the drive gear 12, the sterilized PET container 8 passes through the passage 51 in the radiation shielding tunnel (discharge side) 16b and is fitted to the discharge side star wheel 61. After being held, it is transferred to the next step via the discharge side feed screw 14.

In the event that the PET container 8 being transported in the radiation shielding tunnel 16 falls down and jams, as shown in FIG. 6 and FIG. By opening the opening / closing door 26 constituting the outer peripheral wall of the supply-side or discharge-side tunnel 16 simply by driving and giving an instruction to open the door, the passage 51 of the tunnel 16 is exposed from the outer peripheral side to easily perform jam processing. You can do it.

[0044]

As described above, according to the present invention, it is possible to provide a small and very simple container transporting structure and a radiation shielding tunnel structure, thereby making it impossible to realize an in-line type electronic device which has heretofore been impossible to realize. It becomes possible to realize a line sterilizer.

In particular, according to the first and second aspects of the present invention,
Since the conveying path 51 of the conveyor 18 formed in the shielding tunnel 16 is a bulging curved path 51 having substantially no concave curved path, a return deflection guide is provided along the path 51. Since there is no need to provide the roller 102 and the like, and it is not necessary to form a bent portion in the tunnel passage 51,
There is no need for the moving guide roller 102 provided in the movable section or inside. As a result, the structure of the transport line including the conveyor 18 can be simplified, and lubrication and the like are not required. or,
The transport conveyor 18 does not require a return section for inflection of 90 ° or 180 °, so that the total extension distance of the movable section can be shortened. And the likelihood of bacteria adhering to it is reduced.

According to the first, second and fourth aspects of the present invention, the shape of the tunnel passage is a bulging curved passage,
On the other hand, since the radiation generated from the electron beam irradiation chamber is a straight line, even if the path distance of the curved path is short, a plurality of reflection changes can be performed even if the path distance of the curved path is short. As a result, even if the path distance of the curved path is short, Leakage radiation from the entrance and exit of the radiation shielding tunnel can be attenuated to an allowable level or less, and the size of the clean room can be reduced without unnecessarily increasing the size of the conveyor line.

According to the third aspect of the present invention, since the driving means is outside the tunnel, maintenance is easy and the structure inside the tunnel can be simplified.

Further, according to the fifth and sixth aspects of the present invention,
When jamming or the like of a container that occurs in the radiation shielding tunnel occurs, such as when the hollow container as the object to be irradiated falls or becomes clogged on the conveyor in the radiation shielding tunnel, by opening the opening and closing door, Easy to deal with.

[Brief description of the drawings]

FIG. 1 is a plan view showing the overall configuration of an electron beam sterilizer according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a view taken in the direction of arrows BB in FIG. 2;

FIG. 4 is a side view showing an arrangement of an electron beam irradiation device and a PET container in an electron beam irradiation room.

FIG. 5 is a front view of FIG. 4;

FIG. 6 is a sectional view of a main part showing an opening / closing structure of an opening / closing door of the radiation shielding tunnel shown in FIG. 1;

FIG. 7 is a plan view showing the entire structure of an opening / closing door of the radiation shielding tunnel and its opening / closing drive structure.

FIG. 8 is an operation diagram showing an attenuation path of radiation in the radiation shielding tunnel.

FIG. 9 is an enlarged operation view showing a state in which a PET container is irradiated with an electron beam.

FIG. 10 is a plan view of a comparative technique in a case where shielding of radiation generated when a container is sterilized by electron beam irradiation is configured by a general maze structure.

11 is a cross-sectional view showing a state of transporting the container in a maze surrounded by the transport unit shielding wall in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron beam irradiation apparatus 8 Irradiation object (PET container) 12 Conveyor drive means (drive gear) 16 (16a, 16b) Radiation shielding tunnel 17 Electron beam irradiation room 18 Transport conveyor 26 Opening / closing door 40a-40d, 41a-41d Radiation 50 Electron beam sterilizer 51 passage 52 entrance of shield tunnel 53 exit of shield tunnel

Claims (6)

[Claims] An electron beam sterilizer for irradiating an object having a hollow three-dimensional shape, such as a food container, a beverage container, or a medical container, with an electron beam to achieve an intended purpose such as sterilization. A radiation shielding tunnel having a bulging curved passage having substantially no concave curved path, a conveyor for irradiating an object arranged along the curved passage, and a radiation shielding tunnel halfway along the radiation shielding tunnel; An electron beam irradiation chamber provided, the radiation generated by the electron beam irradiation in the electron beam irradiation chamber is scattered and attenuated while being reflected and deflected by the curved passage in the shield tunnel, and the radiation from the entrance and exit of the shield tunnel is provided. An electron beam sterilizer characterized by attenuating leakage radiation below an allowable level. 2. The curved passage in the radiation shielding tunnel is formed by a perfect circle, an ellipse, an ellipse, a parabola, a hyperbola or a part of these curves, or a combination of a part of these curves and a straight line. The electron beam sterilizer according to claim 1, wherein the passage is provided. 3. The electron beam sterilizer according to claim 1, wherein said conveyor is formed in an endless shape that communicates from an exit portion to an entrance portion of said shielding tunnel, and is connected to a conveyor driving means at a communication portion outside said tunnel. apparatus. 4. The electron beam sterilizer according to claim 1, wherein the electron beam irradiation chamber is provided at a position where the distance between the upstream side and the downstream side in the transport direction of the radiation shielding tunnel is substantially equal. 5. The electron beam sterilizer according to claim 1, wherein an opening / closing door for opening the passage is provided in at least a part of the shielding tunnel. 6. The electron beam sterilizer according to claim 1, wherein the opening and closing door is provided on an outer peripheral side of the shielding tunnel.