JP2021028225A - Electron beam irradiation device and electron beam irradiation method - Google Patents

Abstract

To provide an electron beam irradiation technique for radiating electron beam to the whole outer surface of a bottomed cylindrical container by one electron beam irradiation device and with one irradiation while using electron beam of low energy or medium energy.SOLUTION: An electron beam irradiation device comprises: transport means which holds a bottomed cylindrical container so that a side face thereof faces an irradiation direction of electron beam, and transports the same from an upstream side toward a downstream side; electron beam irradiation means comprising an electron beam irradiation part which accelerates electron beam toward the transported container and radiates the same; and a reflector plate which is located at a position facing the electron irradiation part across the container on a side of a transport path, and has a reflective surface for reflecting irradiated electron beam on a bottom surface of the container. A plurality of rollers, which move in a transport direction while rotating are arranged on the transport means at constant intervals, and this device is configured so as to transport the container while rotating the same between adjacent two rollers.SELECTED DRAWING: Figure 1A

Description

The present invention relates to an electron beam irradiation device and an electron beam irradiation method, and more particularly to an electron beam irradiation device and an electron beam irradiation method using backscattering.

For packaging containers such as pharmaceuticals, cosmetics and beverages, it is obligatory to sterilize and sterilize the containers before filling them, and then fill and seal the contents in a sterile room.

As specific sterilization methods, high-pressure steam sterilization using high-temperature and high-pressure steam, EOG sterilization using ethylene oxide gas (EOG), irradiation sterilization using radiation such as γ-rays and electron beams, and the like are known.

Of these, high-pressure steam sterilization uses high-temperature and high-pressure steam, so a high-pressure chamber is required, and the object must withstand high-temperature and high-pressure. Therefore, high-pressure steam sterilization cannot be said to be a sterilization method suitable for plastic containers widely used in recent years.

Further, although EOG sterilization can be sterilized at a low temperature, the time required for sterilization and removal of residual gas is relatively long. In addition, since EOG has carcinogenicity, stricter regulations are required.

For this reason, in recent years, radiation sterilization has been widely adopted, and among them, electron beam sterilization, which does not require the use of radioactive substances, is increasingly being adopted. In such electron beam irradiation sterilization, not only the outer surface of the container can be sterilized, but also the inner surface of the container can be sterilized depending on the material and thickness of the container.

In conventional electron beam irradiation sterilization, the entire surface of the container is sterilized by irradiating the container with a high-energy electron beam with high penetrating power from the outside of the container to sterilize the electron beam and allow the thickness of the container to pass through. (See Patent Documents 1 and 2). Since this method packs the container, it can be sterilized and then transported to the user.

However, when the above method is adopted, there is a risk that the outer surface of the container is contaminated between the time when the package is opened and the time when the contents are filled. Therefore, there is a demand for an in-line type electron beam irradiation technique capable of continuously performing sterilization and filling of contents in a filling line of contents. Alternatively, there is a need for double packaging to prevent recontamination when opening the package after sterilization in a state of being packed with a high-energy electron beam, and technology for sterilizing the outer surface of the container before filling the contents. Has been done.

In order to perform such in-line electron beam irradiation, the device is required to be small, but the above-mentioned conventional high-energy electron beam irradiation device has a large device scale and shields generated X-rays. In order to do so, a large shield facility such as a concrete shield is required. Therefore, the high-energy electron beam irradiator cannot be said to be suitable for in-line electron beam irradiation.

On the other hand, low-energy and medium-energy electron beam irradiators are small in scale, and the shield equipment may be a small self-shield using a lead shield (see Patent Document 3), so that they can be used for in-line electron beam irradiation. It can be said that it is a suitable facility.

However, the container to be sterilized generally has a bottomed tubular shape. Therefore, if low-energy and medium-energy electron beams with low penetrating power are irradiated from one direction of the container, for example, from the side surface side, the electron beam cannot be irradiated to the back surface side or the bottom surface, and the irradiation is performed. It causes unevenness.

Therefore, as a method for eliminating the occurrence of such irradiation unevenness, for example, a first electron beam accelerator that irradiates an electron beam from the bottom surface side while supporting and transporting the side surface of the tubular container and a tubular container are used. A second electron beam accelerator that irradiates electron beams from the side surface side while supporting and rotating from the bottom surface side is arranged, and irradiation by the first electron beam accelerator and irradiation by the second electron beam accelerator are continuously performed. A continuous sterilization apparatus has been proposed (see Patent Document 4).

However, although such a continuous sterilizer can irradiate an electron beam over the entire circumference of the bottom surface and the side surface of the container, it requires two transport means for the container and two electron beam accelerators, respectively. Larger size is inevitable. In addition, since it is necessary to irradiate the electron beam in two steps, it cannot be said to be an efficient process, and there is a problem in improving productivity.

Japanese Unexamined Patent Publication No. 11-13017 JP-A-2018-95257 Jikkenhei 5-62900 International release WO2013 / 062006

In view of the above-mentioned problems in the conventional electron beam irradiation sterilization, the present invention can be performed with one electron beam irradiation device and one irradiation while using a low energy or medium energy electron beam. An object of the present invention is to provide an electron beam irradiation technique capable of irradiating the entire outer surface of a bottom tubular container with an electron beam.

The present inventor has diligently studied the solution to the above problem, found that the above problem can be solved by the invention described below, and has completed the present invention.

The invention according to claim 1
An electron beam irradiator that irradiates an electron beam toward a bottomed tubular container.
A transport means having a transport path for holding the container so that its side surface faces the irradiation direction of the electron beam and transporting the container from the upstream side to the downstream side.
An electron beam irradiating means including an electron beam irradiating unit that accelerates and irradiates electrons toward the container to be transported along the transport path.
Reflection having a reflecting surface that is arranged on the side of the transport path so as to face the electron beam irradiating portion with the container in between and reflects the electron beam irradiated from the electron beam irradiating portion to the bottom surface of the container. It is equipped with a board,
A plurality of rollers that move in the transport direction while rotating are arranged in the transport means at regular intervals so as to rotate and transport the container arranged between the two adjacent rollers. It is an electron beam irradiation device characterized by being configured.

The invention according to claim 2
The electron beam irradiation device according to claim 1, wherein the reflector is coolable.

The invention according to claim 3
The electron beam irradiation device according to claim 1 or 2, wherein the reflective surface of the reflector is mirror-finished.

The invention according to claim 4
The electron beam irradiation device according to any one of claims 1 to 3, wherein at least the reflective surface of the reflector is formed of metal.

The invention according to claim 5
An electron beam irradiation method for irradiating an electron beam toward a bottomed tubular container using the electron beam irradiation device according to any one of claims 1 to 4.
A transport step of holding the container so that the side surface faces the irradiation direction of the electron beam and transporting the container from the upstream side to the downstream side.
Electrons are accelerated and irradiated toward the side surface of the container to be conveyed through the transport path, and the electron beam irradiated from the electron beam irradiation unit and reflected from the reflection surface of the reflector is applied to the bottom surface of the container. It is equipped with an electron beam irradiation process to irradiate.
In the transfer step, the electron beam irradiation method is characterized in that the container arranged between two adjacent rollers is transferred while rotating.

According to the present invention, while using a low-energy or medium-energy electron beam, the entire outer surface of the bottomed tubular container is irradiated with the electron beam with one electron beam irradiation device and further with one irradiation. It is possible to provide an electron beam irradiation technique that can be used.

In addition, by using the electron beam reflected from the reflector to compensate for the insufficient irradiation of the electron beam on the bottom surface of the container, it is possible to improve the uneven irradiation of the bottom surface and the side surface, so even in a container that is prone to radiation deterioration. It can be sterilized by one unit.

It is a schematic diagram which shows the basic aspect of the electron beam irradiation apparatus which concerns on one Embodiment of this invention. It is the AA arrow view of FIG. 1A. It is a schematic diagram which shows the structure of the reflector of the electron beam irradiation apparatus which concerns on one Embodiment of this invention. It is a schematic view which looked at the reflector of FIG. 2A from the back. It is a schematic diagram which shows the rotation mechanism of a container during electron beam irradiation.

Hereinafter, the present invention will be described based on the embodiments.

[1] Electron beam irradiation device 1. Basic Aspects First, the basic aspects of the electron beam irradiation apparatus of the present embodiment will be described. FIG. 1A is a schematic view showing a basic aspect of the electron beam irradiation device according to the present embodiment, and FIG. 1B is a view taken along the line AA of FIG. 1A.

In FIGS. 1A and 1B, reference numeral 1 denotes an in-line electron beam irradiating device, and an electron beam irradiating unit 11 that radiates and irradiates an electron beam toward the container C is located above the transport path 12 in the container C. It is arranged so as to face with. In the present embodiment, the electron beam irradiation unit 11 accelerates electrons with low energy or medium energy having an acceleration voltage of 1 MV or less, for example. Reference numeral 13 denotes a reflector, which is inclined so as to face the electron beam irradiation unit 11 with the container C on the side of the transport path 12. Further, as shown in FIG. 1B, the container C is arranged between two adjacent rollers of the plurality of rotating rollers 21 and rotates in accordance with the rotation of the rollers 21.

With such a configuration, when the radiated electron beam 11a is irradiated toward the side surface of the container C placed sideways, the radiated electron beam 11a is sufficiently irradiated on the side surface of the rotating container C. , Can be sufficiently sterilized.

However, as shown in FIG. 1A, the radiated electron beam 11a passes parallel to the bottom surface of the container C, which may lead to insufficient irradiation and insufficient sterilization. Therefore, in the present embodiment, the backscattered electron beam 11b is transmitted to the bottom surface B of the container C by reflecting a part of the radiated electron beam 11a that was not irradiated to the container C on the reflecting surface 13a of the reflector 13. It is designed so that it can be irradiated toward.

As a result, sufficient irradiation can be performed by compensating for the insufficient irradiation of the electron beam on the bottom surface B, and even while using a low-energy or medium-energy electron beam, one electron beam irradiation device can be used once more. The entire outer surface of the bottomed tubular container can be sterilized by irradiating it with an electron beam. Further, by compensating for the insufficient irradiation of the electron beam on the bottom surface B, the unevenness of the irradiation on the bottom surface and the side surface can be improved, so that even a container that is prone to radiation deterioration can be sterilized by one unit.

Since the electron beam irradiation unit 11 having an acceleration voltage of 1 MV or less is small, the entire electron beam irradiation device 1 can also be miniaturized, which is preferable as an in-line sterilization facility.

In the present embodiment, if necessary, the contents are not irradiated with the electron beam by using the low-energy electron beam for the container filled with the contents in advance before the electron beam irradiation. It is also possible to irradiate only the outer surface of the container.

2. 2. Characteristic part of the electron beam irradiation device Next, among the specific aspects of the electron beam irradiation device of the present embodiment, the reflector and the roller which are the feature parts will be described.

(1) Reflector As described above, with respect to the bottom surface B of the container C, since the radiated electron beam 11a passes parallel to the bottom surface of the container C, there is a risk of insufficient irradiation as compared with the side surface. However, in the present embodiment, the reflector 13 is arranged at a position facing the electron beam irradiation unit 11 with the container C on the side of the transport path 12, and the radiated electron beam 11a is reflected by the reflector 13. By backscattering on the surface 13a, the backscattered electron beam 11b is configured to irradiate the bottom surface B of the container C. Therefore, the bottom surface B of the container C can be efficiently irradiated with the electron beam, and the entire surface of the container C can be sufficiently sterilized while being irradiated once using one electron beam irradiation device. It can be performed. Further, by compensating for the insufficient irradiation of the electron beam on the bottom surface B, the unevenness of the irradiation on the bottom surface and the side surface can be improved, so that even a container that is prone to radiation deterioration can be sterilized by one unit.

FIG. 2A is a schematic view showing the configuration of the reflector 13 of the electron beam irradiation device according to the present embodiment, and FIG. 2B is a schematic view of the reflector 13 as viewed from the back. In FIGS. 2A and 2B, reference numeral 14 denotes a support device for supporting the reflector 13. Note that θ is the inclination angle, and c is the refrigerant.

By supporting the reflector 13 with the support device 14 so that the inclination angle θ of the radiated electron beam 11a with respect to the radiation direction can be changed, the reflection angle from the radiated electron beam 11a to the backward scattered electron beam 11b can be arbitrarily adjusted. it can. As a result, the backscattered electron beam 11b can be reliably irradiated at a desired position on the bottom surface B of the container C.

In the present embodiment, it is preferable that the reflector 13 can be cooled by providing a cooling device on the support device 14.

By cooling the reflector 13, it is possible to prevent the temperature of the reflector 13 from rising when the radiated electron beam 11a is continuously irradiated toward the reflector 13 for a long time. As a specific cooling method, for example, as shown in FIG. 2B, a method of passing a refrigerant c such as cooling water or an LLC coolant having a high cooling effect through a pipe 30 fixed to the back side of the reflector 13 is also possible. Is.

The reflective surface 13a is preferably mirror-finished. As a result, the radiated electron beam 11a can be backscattered more efficiently, so that the radiated electron beam 11a can be used more efficiently to increase the dose of the backscattered electron beam 11b.

Further, it is preferable that at least the reflecting surface 13a of the reflecting plate 13 is formed of a metal having an excellent backscattering function with respect to an electron beam.

Specific examples of the metal include heavy metals such as tungsten (W) and gold (Au). These metals may be used up to the inside of the reflector 13 in a so-called bulk state, but may also be used only for the surface portion involved in backscattering, such as forming a thin film by surface-coating the reflecting surface 13a. Good.

(2) Rollers As shown in FIG. 1, in the present embodiment, a plurality of rollers 21 that move in the transport direction while rotating are arranged at regular intervals in the transport path 12. The container C is arranged between two adjacent rollers 21. Therefore, the container C rotates in accordance with the rotation of the roller 21, and the side surface on which the radiated electron beam 11a is irradiated is constantly changed, so that a sufficient amount of the radiated electron beam 11a is applied to the entire side peripheral surface of the container C. It will be irradiated. As a result, the side surface of the container C can be sufficiently sterilized. Reference numeral 21c is a flange portion provided at the end of the side surface of the roller 21 to support the container C from the bottom surface B side.

Further, as shown in FIG. 1B, when the container C is arranged between the two horizontally arranged rollers 21, the container C does not need to be held by a chuck or the like, so that no shadow is formed and the container C is formed. The entire surface of the side surface can be irradiated with the radiation electron beam 11a.

If the rollers 21 are arranged at a completely horizontal angle, the container C that rotates with the rotation of the rollers 21 may move on the rollers 21, so that the rollers 21 have a predetermined angle. It is preferably arranged at an angle of 1 to 80 °. As a result, the container C rotates while being supported by the collar portion, so that the movement on the roller 21 can be prevented.

(3) Rotation mechanism FIG. 3 is a schematic view showing a rotation mechanism of the container during electron beam irradiation. In FIG. 3, 22a is a fixing member, 22b is a support member, 22c is a roller holding member, and 22d is a fulcrum. The rotation shaft of the roller 21 has protrusions on both sides of the roller holding member 22c, and the roller 21 is attached to one end and the pinion 24a is attached to the other end. Further, 24b is a rack and is arranged in parallel along the transport path.

As shown in FIG. 3, when the roller support device is carried into the transport path, the pinion 24a meshes with the rack 24b, and the roller support device moves in the transport direction to rotate the roller 21. As a result, the electron beam can be irradiated while rotating the container C.

By combining the pinion 24a and the rack 24b in this way, the rotation mechanism can be made simple and the risk of failure can be reduced. Further, since the rotation speed of the roller 21 is determined by the ratio of the number of teeth of the pinion 24a and the rack 24b, the rotation speed of the roller 21 does not fluctuate even if the transport speed fluctuates. Therefore, for example, in order to adjust the irradiation dose, the rotation speed can be kept constant even when the transport speed is changed.

3. 3. More Preferred Embodiment (1) Inclination Angle of Reflecting Surface of Reflector The reflector 13 is preferably supported so that the inclination angle θ of the reflecting surface 13a can be changed. Specifically, in FIG. 2B, for example, the pipe 30 supports the reflector 13 so that the inclination of the reflector 13 can be freely changed around the center in the width direction of the reflector. As a result, the backscattered electron beam 11b can be applied to a desired position even for containers having various sizes and forms.

(2) Surface Shape and Material of Roller It is preferable that at least a part of the side surface of the portion 21a in contact with the container C of the roller 21 is knurled or satin finished over the entire circumference. By performing such processing, the frictional force between the container C and the side surface of the roller 21 is increased, so that the container C becomes less slippery with respect to the roller 21, and the container C is surely adjusted to the rotating roller 21. The container C can be rotated.

Specific forms of knurling include knurling and fluttering in which the eyes are formed along the axial direction of the roller 21. Moreover, as a form of satin finish, known surface treatment such as etching, sandblasting, and honing can be mentioned. The size of the knurled mesh and the roughness of the satin finish are appropriately determined according to the material of the container, the size of the curvature of the side surface, the surface roughness and the like.

Further, it is preferable that at least a part of the side surface of the portion 21b that does not come into contact with the container C of the roller 21 is mirror-finished over the entire circumference. Specifically, as shown in FIG. 1A, it is preferable that the length of the roller 21 is made larger than the height of the container C, and the side surface of a part of the portion 21b that does not come into contact with the container C is mirror-finished.

As a result, the radiated electron beam 11a is reflected and scattered backward toward the container C in the mirror-finished portion, so that the lid portion of the top T of the container C where the irradiation dose of the radiated electron beam 11a is small, etc. Can also be sterilized by irradiating backscattered electron beams from the mirrored side surface of the roller 21.

In order to obtain such an effect, it is preferable that at least the side surface portion of the roller 21 is formed of metal, as in the case of the reflector.

(3) Change of roller posture Electron beam irradiation is performed by arranging the container horizontally and sideways. On the other hand, since the filling of the contents into the container is usually performed by erecting the container, it is preferable to change the posture of erecting the container after the electron beam irradiation.

[2] Electron beam irradiation method Next, an electron beam irradiation method for irradiating an electron beam toward a bottomed tubular container using the above-mentioned electron beam irradiation device will be described.

In the present embodiment, the container can be sterilized by irradiating the container with an electron beam by going through the following two steps using the above-mentioned electron beam irradiation device.

That is, the transport process of holding the container so that the side surface faces the irradiation direction of the electron beam and transporting the container from the upstream side to the downstream side, and accelerating the electrons toward the side surface of the container to be transported along the transport path. The two steps are an electron beam irradiation step of irradiating the bottom surface of the container with an electron beam that is irradiated from the electron beam irradiation unit and reflected from the reflecting surface of the reflecting plate.

Then, through such a process, by irradiating the electron beam toward the bottomed tubular container, as described in the above description of the electron beam irradiating device, not only the side surface of the container but also the bottom surface and the top surface. It is possible to irradiate the electron beam sufficiently. As a result, while using a small electron beam irradiation unit that accelerates and irradiates electrons with low energy or medium energy with an acceleration voltage of 1 MV or less, the electron beam can be efficiently applied to the entire outer surface of the tubular container with a single irradiation. Can be irradiated.

Further, by compensating for the insufficient irradiation of the electron beam on the bottom surface, it is possible to improve the uneven irradiation of the bottom surface and the side surface, so that even a container that is easily deteriorated by radiation can be sterilized by one unit.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. It is possible to make various modifications to the above embodiments within the same and equivalent scope as the present invention.

1 Electron beam irradiation device 11 Electron beam irradiation unit 11a Radiation electron beam 11b Backscattered electron beam 12 Transport path 13 Reflector 13a Reflection surface 14 Support device 21 Roller 21a Part that contacts the container 21b Part that does not contact the container 21c Border 22a Fixed Member 22b Support member 22c Roller holding member 22d Supporting point 24 Rotating mechanism 24a Pinion 24b Rack 30 Piping B Bottom surface C Container T Top c Refrigerator θ Tilt angle

Claims (5)

An electron beam irradiator that irradiates an electron beam toward a bottomed tubular container.
A transport means having a transport path for holding the container so that its side surface faces the irradiation direction of the electron beam and transporting the container from the upstream side to the downstream side.
An electron beam irradiating means including an electron beam irradiating unit that accelerates and irradiates electrons toward the container to be transported along the transport path.
Reflection having a reflecting surface that is arranged on the side of the transport path so as to face the electron beam irradiating portion with the container in between and reflects the electron beam irradiated from the electron beam irradiating portion to the bottom surface of the container. It is equipped with a board,
A plurality of rollers that move in the transport direction while rotating are arranged in the transport means at regular intervals so as to rotate and transport the container arranged between the two adjacent rollers. An electron beam irradiation device characterized by being configured. The electron beam irradiation device according to claim 1, wherein the reflector is coolable. The electron beam irradiation device according to claim 1 or 2, wherein the reflective surface of the reflector is mirror-finished. The electron beam irradiating apparatus according to any one of claims 1 to 3, wherein at least the reflecting surface of the reflecting plate is formed of metal. An electron beam irradiation method for irradiating an electron beam toward a bottomed tubular container using the electron beam irradiation device according to any one of claims 1 to 4.
A transport step of holding the container so that the side surface faces the irradiation direction of the electron beam and transporting the container from the upstream side to the downstream side.
Electrons are accelerated and irradiated toward the side surface of the container to be conveyed through the transport path, and the electron beam irradiated from the electron beam irradiation unit and reflected from the reflection surface of the reflector is applied to the bottom surface of the container. It is equipped with an electron beam irradiation process to irradiate.
In the transfer step, an electron beam irradiation method characterized in that the container arranged between two adjacent rollers is transferred while rotating.

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