JP7205802B2 - Electron beam irradiation device and electron beam irradiation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electron beam irradiation apparatus and an electron beam irradiation method, and more particularly to an electron beam irradiation apparatus and an electron beam irradiation method involving a rotary transport mechanism.

For packaging containers such as pharmaceuticals, cosmetics and beverages, it is obligatory to sterilize the container to aseptic conditions before filling the contents, and then fill and seal the contents in an aseptic room.

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

Among these methods, high-pressure steam sterilization uses high-temperature, high-pressure steam, and therefore requires a high-pressure chamber, and the object to be sterilized must withstand high temperature and high pressure. For this reason, high-pressure steam sterilization cannot be said to be a sterilization method suitable for plastic containers that have been widely used in recent years.

In addition, EOG sterilization allows sterilization at low temperatures, but the time required for sterilization and residual gas removal is relatively long. In addition, since EOG is carcinogenic, stricter regulations are required.

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

Conventional electron beam irradiation sterilization involves sterilizing the entire surface of a container by irradiating a high-energy electron beam with high penetrating power from the outside of the package while the container is packed, and allowing the electron beam to penetrate the package and the thickness of the container. (See Patent Documents 1 and 2). This method packs the container so that it can be sterilized and then transported to the user.

However, when the above method is employed, there is a risk of contamination of the outer surface of the container between the time the package is opened and the time the content is filled. For this reason, an in-line type electron beam irradiation technology capable of continuously performing sterilization and filling of contents in a contents filling line is desired. In addition, in order to prevent recontamination when opening the package after sterilizing it with a high-energy electron beam, double packaging is used, and the outer surface of the container is sterilized before the contents are filled. is also required.

In order to perform such in-line electron beam irradiation, it is required that the device be small. In order to do so, a large shield facility such as a concrete shield is required. Therefore, the high-energy electron beam irradiation apparatus cannot be said to be equipment suitable for in-line electron beam irradiation.

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

However, containers to be sterilized generally have a cylindrical shape with a bottom. For this reason, if low-energy and medium-energy electron beams with low penetrating power are irradiated from one direction, for example, the side surface of the container, the electron beam cannot be irradiated to the back side or the bottom surface of the container. 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 side while supporting the side surface of the cylindrical container and transporting it, and a cylindrical container. A second electron beam accelerator that irradiates an electron beam from the side portion side while being supported from the bottom portion side and rotated on its axis is arranged, and the irradiation by the first electron beam accelerator and the 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 sterilization apparatus can irradiate the entire circumference of the bottom surface and side surfaces of the container with electron beams, it requires two container transport means and two electron beam accelerators, respectively. An increase in size is inevitable. In addition, since the electron beam irradiation must be performed in two steps, it cannot be said to be an efficient treatment, which poses a problem in terms of improving productivity.

JP-A-11-130172 JP 2018-95257 A Japanese Utility Model Laid-Open No. 5-62900 International publication WO2013/062006

In view of the various problems in the conventional electron beam irradiation sterilization described above, the present invention uses a single electron beam irradiation apparatus 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 cylindrical bottom container with an electron beam.

The present inventors have earnestly studied how to solve the above problems, found that the above problems can be solved by the invention described below, and completed the present invention.

The invention according to claim 1,
An electron beam irradiation device that irradiates an electron beam toward a bottomed cylindrical container,
a conveying means having a conveying path that holds the container so that the side faces face the irradiation direction of the electron beam and conveys the container from the upstream side to the downstream side;
an electron beam irradiation means including an electron beam irradiation unit that accelerates and irradiates electrons toward the container transported on the transport path,
In the conveying means, a plurality of rollers that move in the conveying direction while rotating are arranged at regular intervals with an inclination with respect to the conveying direction, and the containers are arranged between the two adjacent rollers. It is configured to be conveyed while being rotated,
The roller is provided with a collar portion that protrudes radially from the side surface over the entire circumference of the side surface at one end in the longitudinal direction, and changes the inclination angle of the rotation axis of the roller with respect to the vertical direction. It is equipped with a variable angle mechanism that can
The electron beam irradiation apparatus is characterized in that an irradiation angle of the electron beam to the container is adjusted by adjusting the inclination angle.

The invention according to claim 2,
2. The electron beam irradiation apparatus according to claim 1, wherein the protrusion width of said flange is smaller than the distance between the side surface of said container and the center of rotation of said container.

The invention according to claim 3,
3. The electron beam irradiation apparatus according to claim 1, wherein a surface of the flange portion that contacts the container is mirror-finished.

The invention according to claim 4,
4. The electron beam irradiation apparatus according to any one of claims 1 to 3, wherein a surface of the flange portion that contacts the container is made of metal.

The invention according to claim 5,
An electron beam irradiation method for irradiating a bottomed cylindrical container with an electron beam using the electron beam irradiation apparatus according to any one of claims 1 to 4,
a conveying step of conveying the container placed by adjusting the inclination angle of the roller from the upstream side to the downstream side while holding the container so that the side faces face the irradiation direction of the electron beam at a predetermined angle; ,
and an electron beam irradiation step of accelerating and irradiating electrons toward the side surface of the container conveyed on the conveying path,
In the transporting step, the electron beam irradiation method is characterized in that the container placed between the two adjacent rollers is transported while being rotated.

According to the present invention, an electron beam that can irradiate the entire outer surface of a cylindrical container with a single electron beam irradiation apparatus while using a low-energy or medium-energy electron beam. Irradiation technology can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the basic aspect of the electron beam irradiation apparatus which concerns on one embodiment of this invention. FIG. 1B is a view taken along line AA of FIG. 1A. It is a schematic diagram which shows the aspect of the electron beam irradiation apparatus which concerns on other one embodiment of this invention. 1 is a perspective view showing the configuration of a roller support device of an electron beam irradiation device according to an embodiment of the present invention; FIG. It is a figure explaining an angle variable mechanism. It is a schematic diagram explaining the rotation mechanism of a roller. FIG. 4 illustrates a preferred embodiment of rollers and the use of backscattered electron beams;

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on embodiments.

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

In FIGS. 1A and 1B, reference numeral 1 denotes an in-line electron beam irradiation apparatus. An electron beam irradiation unit 11 for irradiating an electron beam toward a container C is connected to the container C supported at an angle. They are arranged obliquely above the conveying path 12 so as to face each other. In addition, in the present embodiment, the electron beam irradiation unit 11 accelerates electrons with low energy or medium energy, for example, an acceleration voltage of 1 MV or less.

The conveying path 12 is composed of a plurality of rollers 21 supported by a roller support device 22 with their rotating shafts inclined. The container C is placed between two adjacent rollers of a plurality of rotating rollers 21 and conveyed downstream while being rotated.

In this embodiment, an angle variable mechanism is provided that can change the tilt angle of the rotation shaft of the roller 21 with respect to the vertical direction. In FIG. 1A, CL is the center line of the rotating shaft of the roller 21, and θ is the inclination angle of the rotating shaft with respect to the vertical direction.

With the configuration as described above, even if the container C is transported in an inclined state, the container C can be transported without being dropped from the apparatus because the container C is supported by the collar portion 21c. By conveying the container in an inclined state, the container can be conveyed in a state that is not completely upright or in a state that is not completely horizontal. It becomes easy to combine with processes such as Also, the height and width of the device can be suppressed, and the size of the device can be reduced.

Then, the radiated electron beam 11a is irradiated from the electron beam irradiation unit 11 arranged obliquely toward the side surface of the container C which is placed obliquely on the rollers 21 and transported while rotating, thereby irradiating the container. The electron beam can be irradiated to the entire circumference of the side surface. In addition, since part of the emitted electron beam 11a also goes around toward the bottom surface B and the top portion T of the container C, even though a low-energy or medium-energy electron beam irradiation device is used, only one electron beam irradiation device can , the entire outer surface of a cylindrical container with a bottom can be irradiated with electron beams in a single irradiation for sufficient sterilization.

Since the electron beam irradiation unit 11 that accelerates and irradiates low-energy or medium-energy electrons is small, the entire electron beam irradiation apparatus 1 can be made compact, which is preferable as an in-line sterilization facility.

Further, in the present embodiment, the container C can be conveyed while being rotated on the rollers 21 without being sandwiched between guides and rollers or gripped with a chuck or the like. There is no shadow area where the electron beam is not irradiated. In addition, since the roller 21 rotates to move the shadow portion of the container, the electron beam can be applied to the entire surface of the bottom surface B and the top portion T of the shadow portion of the container by the flange portion 21c. can be done.

Furthermore, in this embodiment, as described above, since the angle variable mechanism is provided, the angle of the emitted electron beam 11a with respect to the container C can be changed by adjusting the inclination angle θ. Even if the electron beam is difficult to irradiate due to the shape of C and there is a risk of creating a shadowed portion, the position of the container can be freely adjusted by changing the inclination angle θ, and the electron beam irradiation location can be adjusted. It is possible to irradiate the shadow part. It should be noted that the specific inclination angle θ is preferably 15 to 90°.

Further, in the present embodiment, if necessary, a low-energy electron beam is used to irradiate a container filled with contents in advance before electron beam irradiation, without irradiating the contents with an electron beam. It is also possible to irradiate only the outer surface of the container.

2. Characteristic Part of Electron Beam Irradiation Apparatus Next, the characteristic part of the electron beam irradiation apparatus of the present embodiment will be described.

(1) Roller As shown in FIG. 1A, in the present embodiment, a plurality of rollers 21 rotating and moving in the transport direction are arranged in the transport path 12 so as to face the irradiation direction of the electron beam. They are supported by the roller supporting device 22 with the rotating shaft inclined, that is, at an inclination angle θ forming an acute angle with respect to the vertical direction of the rotating shaft, and are arranged at regular intervals. As described above, the end portion of the roller 21 is provided with the flange portion 21c to support the inclined container C from the bottom surface B side.

As a result, the container C can be conveyed while being rotated on the rollers 21 without being sandwiched between guides and rollers or gripped by a chuck or the like. does not occur. For this reason, even if one electron beam irradiation apparatus is used for one irradiation, the electron beam is applied to the entire outer surface of the container C by utilizing the wraparound of the emitted electron beam 11a to the bottom surface B, the top portion T, and the like. Can be irradiated.

However, when the irradiation direction of the electron beam to the container and the attitude of the container are fixed, the electron beam is difficult to irradiate depending on the shape of the container C, and there is a possibility that a shaded portion may occur. The occurrence of such shadows can be suppressed by adjusting either the irradiation direction of the electron beam or the attitude of the container. Since the position must be changed, it requires a large space and a complicated mechanism, which is not preferable.

On the other hand, when the tilt angle θ of the roller 21 is variable by providing an angle variable mechanism that does not require a complicated mechanism as in the present embodiment, the tilt angle θ can be freely changed by a simple mechanism. Since it can be changed, the posture of the container can be easily and freely adjusted, and a large space is not required.

In the present embodiment, at least a part of the side surface of the portion 21a of the roller 21 that contacts the container C is preferably knurled or satin-finished over the entire circumference. By applying such a process, 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 against the roller 21, and the roller 21 rotates. Container C can be rotated.

In addition, as a specific form of knurling processing, crochet processing and flattening processing in which a mesh is formed along the axial direction of the roller 21 can be mentioned. Examples of the satin finish include known surface treatments such as etching, sandblasting, and honing. The size of the knurled mesh and the degree of roughness of the satin finish are appropriately determined according to the material of the container, the degree of curvature of the side surface, the degree of surface roughness, and the like.

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

As a result, the radiant electron beam 11a is reflected and backscattered toward the container C at the mirror-finished portion, so that the irradiation dose of the radiant electron beam 11a is small. can also be sterilized by irradiating backscattered electron beams from the mirror-finished 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 using a metal that is excellent in the function of backscattering electron beams.

Preferred metals include, for example, heavy metals such as tungsten (W) and gold (Au). These metals may be used in a so-called bulk state up to the inside of the roller 21, but may be used only for the surface portion involved in backscattering, such as by coating the surface to form a thin film.

(2) Flange In the present embodiment, as described above, the flange 21c is provided at the end of the roller 21 and supports the container C conveyed in an inclined state.

(a) Projection Width of Collar Portion For this reason, the projecting width of the collar portion 21c is basically a width that allows the container C to be supported by the collar portion 21c in a state in which the roller 21 is tilted. and the center of rotation of container C. Specifically, for example, when the container C is cylindrical, it is preferable that the radius is smaller than the radius of the container C. In addition, a non-cylindrical container, such as a cylindrical container with an elliptical cross section, is used. For non-constant containers, preferably less than the minimum distance.

A part of the bottom surface B of the container C is temporarily shaded by the flange 21c. Since the portion moves, the entire bottom surface B can be sufficiently irradiated with the emitted electron beam.

(b) Surface state and material of collar portion It is preferable that the surface of the collar portion 21c in contact with the container C is mirror-finished. This reduces the frictional force between the flange 21c and the container C when the roller 21 and the container C are rotated, so that the container C can be rotated smoothly. In addition, such mirror finishing can improve the electron beam backscattering function of the collar portion 21c.

Moreover, at least the surface that comes into contact with the container C is preferably made of a heavy metal such as tungsten (W) or gold (Au), which has an excellent backscattering function for electron beams.

(3) Roller support device FIG. 3 is a perspective view showing the structure of the roller support device 22, and FIG. 4 is a diagram explaining an angle variable mechanism.

As shown in FIG. 3, the roller support device 22 has metal fixing members 22a, support members 22b, and roller holding members 22c. The support member 22b is composed of two plate members, which are arranged vertically and in parallel at a predetermined interval, and erect vertically on the outer surface of the fixing member 22a. The roller holding member 22c has a bearing portion that holds the rotating shaft of the roller 21, and a plate that stands perpendicular to the surface of the bearing portion facing the fixed member 22a and in the same direction as the rotating shaft of the roller 21. ing.

The plate member of the roller holding member 22c is inserted between the two plate members of the support member 22b, and supported so as to be able to turn about the fulcrum 22d together with the two plate members of the support member 22b. As a result, as shown in FIG. 4, the roller 21 can be turned around the fulcrum 22d along a vertical plane, thereby forming an angle variable mechanism capable of changing the tilt angle θ.

By providing such an angle variable mechanism and varying the inclination angle θ of the roller 21, the angle formed between the radiation direction of the radiation electron beam 11a and the axis of the container C, i.e., the irradiation angle with respect to the container C can be preferably adjusted. It can be adjusted according to the angle.

Protrusions are provided on the upper and lower sides of the roller support device 22, the roller 21 is attached to the upper protrusion, and the pinion 24a is attached to the lower protrusion.

(4) Roller Rotation Mechanism FIG. 5 is a schematic diagram illustrating a roller rotation mechanism. In FIG. 5, 24b is a rack, which is arranged in parallel along the transport path. As shown in FIG. 5, when the roller support device 22 is carried into the transport path, the pinion 24a meshes with the rack 24b, and the roller 21 rotates as the roller support device 22 moves in the transport direction. Thereby, the electron beam can be irradiated while the container C is rotated.

By combining the pinion 24a and the rack 24b in this way, it is possible to simplify the configuration of the rotation mechanism and reduce the risk of failure. 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 conveying speed fluctuates. Therefore, even if the conveying speed is changed in order to adjust the irradiation dose, for example, the number of rotations can be kept constant.

3. More Preferred Aspects Next, more preferred aspects of the present embodiment will be described.

(1) Reflector FIG. 6 is a diagram illustrating a preferred embodiment of rollers and utilization of backscattered electron beams. In FIG. 6, 21a is the portion of the roller that contacts the container C, and 21b is the portion that does not contact. 13 is a reflector.

As shown in FIG. 6, in this embodiment, if necessary, a reflector 13 may be arranged to irradiate the container C with the backscattered electron beam 11b backscattered by the reflector 13 . The reflector 13 has a high degree of freedom in its installation position and scattering direction. For this reason, it is possible to irradiate locations that are difficult to irradiate by backscattering of a roller, which is preferable.

(2) Electron Beam Irradiation Unit The electron beam irradiation unit 11 is installed so that its longitudinal direction is parallel to a plane perpendicular to the transport path. At this time, as shown in FIG. 1A, by inclining the longitudinal direction in the same direction as the rotation axis of the roller 21 at an angle of 15 to 90° with respect to the vertical direction, the height direction of the electron beam irradiation unit 11, And the installation space in the width direction can be reduced.

In addition, the electron beam irradiation unit 11 is a support device having a position adjusting mechanism for adjusting the position in the height direction and the horizontal direction on a plane perpendicular to the transport path and a radial direction adjusting mechanism for adjusting the radiation direction of the electron beam. It is preferably supported by By using a variable angle mechanism, a position adjustment mechanism, and a radiation direction adjustment mechanism, a high degree of freedom can be obtained for irradiation conditions. Can be irradiated.

(3) Conveying Means When irradiating the electron beam, the container C is held in an inclined state at an inclination angle θ with respect to the vertical direction as described above. On the other hand, before and after the irradiation with the electron beam, a process such as filling the container C with the content is preferably performed to hold the container C in an upright state. For this reason, the conveying means is configured to change the container, which is held in an upright state on the upstream side of the electron beam irradiation area, to an inclined state, and on the downstream side of the electron beam irradiation area, to return the container from the inclined state to the upright state. preferably.

Specifically, for example, a known mechanism is installed to transfer the container C carried in to the upstream end of the transport means from the upstream transport means to the roller 21, while the container C is transported to the downstream end of the transport means. A configuration such as installing a mechanism for transferring the container C from the roller 21 to the conveying means in the downstream process is used.

[2] Electron Beam Irradiation Method Next, an electron beam irradiation method for irradiating a bottomed cylindrical container with an electron beam using the electron beam irradiation apparatus described above will be described.

In the present embodiment, the container can be sterilized by irradiating electron beams through the following two processes using the electron beam irradiation apparatus described above.

That is, a conveying step in which a container in an inclined state is held so that its side surface faces the irradiation direction of the electron beam and is conveyed from the upstream side to the downstream side; There are two processes, one is an electron beam irradiation process in which rays are emitted and irradiated.

Then, through such steps, by irradiating an electron beam toward the cylindrical container with a bottom, as described in the above description of the electron beam irradiation apparatus, not only the side surface of the container but also the bottom surface and top portion can be exposed. can be sufficiently irradiated with an electron beam. As a result, the entire outer surface of the cylindrical container can be efficiently irradiated with an electron beam in a single irradiation, while using a small-sized electron beam irradiation unit that irradiates a low-energy or medium-energy electron beam at an acceleration voltage of 1 MV or less. be able to.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiment within the same and equivalent scope of the present invention.

1 electron beam irradiation device 11 electron beam irradiation unit 11a emitted electron beam 11b backscattered electron beam 12 transport path 13 reflector 21 roller 21a portion 21b in contact with container portion 21c not in contact with container flange 22 roller support device 22a fixing member 22b Support member 22c Roller holding member 22d Fulcrum 24 Rotation mechanism 24a Pinion 24b Rack C Container B Bottom surface T Top θ Tilt angle CL Center line of rotation axis

Claims (5)

An electron beam irradiation device that irradiates an electron beam toward a bottomed cylindrical container,
a conveying means having a conveying path that holds the container so that the side faces face the irradiation direction of the electron beam and conveys the container from the upstream side to the downstream side;
an electron beam irradiation means including an electron beam irradiation unit that accelerates and irradiates electrons toward the container transported on the transport path,
In the conveying means, a plurality of rollers that move in the conveying direction while rotating are arranged at regular intervals with an inclination with respect to the conveying direction, and the containers are arranged between the two adjacent rollers. It is configured to be conveyed while being rotated,
The roller is provided with a collar portion that protrudes radially from the side surface over the entire circumference of the side surface at one end in the longitudinal direction, and changes the inclination angle of the rotation axis of the roller with respect to the vertical direction. It is equipped with a variable angle mechanism that can
An electron beam irradiation apparatus, wherein an irradiation angle of the electron beam to the container is adjusted by adjusting the inclination angle. 2. An electron beam irradiation apparatus according to claim 1, wherein the protrusion width of said flange is smaller than the distance between the side surface of said container and the center of rotation of said container. 3. The electron beam irradiation apparatus according to claim 1, wherein a surface of said flange portion that contacts said container is mirror-finished. 4. The electron beam irradiation apparatus according to any one of claims 1 to 3, wherein a surface of said flange portion that contacts said container is formed using a metal. An electron beam irradiation method for irradiating a bottomed cylindrical container with an electron beam using the electron beam irradiation apparatus according to any one of claims 1 to 4,
a conveying step of conveying the container placed by adjusting the inclination angle of the roller from the upstream side to the downstream side while holding the container so that the side faces face the irradiation direction of the electron beam at a predetermined angle; ,
and an electron beam irradiation step of accelerating and irradiating electrons toward the side surface of the container conveyed on the conveying path,
The electron beam irradiation method, wherein in the transporting step, the container placed between the two adjacent rollers is transported while being rotated.

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