JP2002006095A - High energy electron beam irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high energy electron beam irradiation device capable of effectively removing ozone in an electron beam irradiation area with a simple structure. SOLUTION: In a high energy electron beam irradiation device constituted by providing a suction opening facing to an irradiation area for irradiating high energy electron beam to a solid irradiation object and removing ozone generated in the irradiation area, the suction opening is formed in a hood shape or more specifically a range hood shape and the hood is arranged in an upper space of the electron beam irradiation area. The hood shape openings are arranged in both an upper space and a lower space of the electron beam irradiation area. During operation of the electron beam irradiation, ozone is sucked from the suction opening arranged in the upper space, and during shutdown of the electron beam irradiation operation, residual ozone is locally and effectively sucked from the suction opening given in the lower space of the irradiation area in the constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam which achieves an intended purpose such as sterilization while irradiating a product requiring sterilization such as a drinking water container or a medical device with a high energy electron beam. The present invention relates to an irradiation device.

[0002]

2. Description of the Related Art Conventionally, sterilization of drinking water containers, medical equipment, and the like, which generally require sufficient sterilization and the like, includes high-pressure steam sterilization, ethylene oxide gas sterilization, and γ-ray sterilization. It has been subjected. Among them, the electron beam irradiation sterilization method enables sterilization of medical equipment and the like by increasing the acceleration voltage of the electron beam. Can be processed in a very short time, and when the power is turned off, the irradiation is stopped instantaneously, which has advantages such as high environmental safety and low cost. Further, the difference from γ-ray irradiation is that it is said that material deterioration is small. For this reason, there is a possibility that the range of material selection may be expanded.

[0003] However, this technique also has the following problems. That is, 5 to 10 Me is applied to the irradiation object.
When a high energy electron beam of V, 25 Kw is irradiated, the electron beam generates ozone of about 30 to 40 ppm which greatly exceeds the environmental standard (0.1 ppm) due to the synthesis of air (oxygen) in the cylinder. The ozone is highly oxidizing and may have harmful effects on the human body. Moreover, not only is it extremely environmentally problematic, but also there is a risk that the worker may inhale the ozone when exchanging an object to be irradiated which has been conveyed to the irradiation conveyor and sent out of the apparatus.

In order to solve this problem, attention is paid to the fact that ozone (molecular weight: 48) is heavier than air (molecular weight: about 29), and electrons between an electron beam irradiation apparatus and an object to be irradiated are irradiated. Although a range hood-shaped suction opening is arranged below the line irradiation space to suction ozone generated in the irradiation area, effective ozone suction cannot always be performed.

[0005] As described in the embodiments described later, an electron beam irradiation apparatus for irradiating a high energy electron beam has a horn-like vacuum area on the exit side of the electron beam, and has an external communication space area and an irradiation area. An electron beam permeable film is stretched over the irradiation window located between them to provide an airtight seal with the outside world, and the periphery of the electron beam permeable film is held on the horn-shaped irradiation unit side by a flange-shaped mounting flange. It is fixed.

As described above, in such a high energy electron beam irradiation apparatus, the electron beam transmitted through the electron beam permeable film reacts with oxygen in the air to generate ozone, as described above. In the electron beam, large heat energy is generated on the electron beam permeable film. Therefore, as shown in FIG. 1 described below, a cooling nozzle is arranged at a position on the side of the electron beam permeable film (titanium film). Although the titanium film surface is configured to be air-cooled by the jet air flow,
Ozone near the irradiation area is agitated by the cooling air, and ozone cannot be effectively sucked by a range hood-shaped ozone suction device provided below.

[0007] In order to eliminate such a drawback, the present applicant has disclosed in Japanese Patent Application No. 11-142065 as a prior application technology shown in FIG.
The following ozone suction device has been proposed. That is, FIG. 3 shows a technique of irradiating an electron beam 8 in a state in which a stainless steel cylinder 10 in which an object to be irradiated 1 is stored is placed in a horizontal state. The cylinder 10 is a hollow cylinder having an open right surface in the figure. None, and the bottom wall on the left side of the disk-shaped figure is cut and raised into a screw shape to function as the fan 101. On the other hand, on the conveyor 2, a large number of a pair of V-shaped support bases 102 each having a rotating roller (not shown) incorporated therein are arranged in the conveying direction.
Is mounted on the V-shaped support 102 such that the axis of the cylindrical body coincides with the direction perpendicular to the conveying direction of the conveyor 2. An electron beam irradiator 3 for beam-scanning the electron beam 8 in a direction orthogonal to the conveyor conveyance direction is provided above the conveyor 2, and the ozone adsorber 103 is attached to the conveyor 2 located in the electron beam irradiation area. It is arranged on the side.

According to the prior art, the cylindrical bodies 10 each containing the object 1 to be irradiated are placed on the pair of V-shaped support tables 102 in a direction perpendicular to the conveying direction of the conveyor 2.
At the point when it enters the electron beam irradiation area while transporting the conveyor 2, the cylindrical body 10 is rotated by the rotating rollers in the support base 102.
The object 1 is irradiated with an electron beam having an energy of 10 MeV from the electron beam irradiation device 7 by rotating.
As a result, the airflow from the bottom surface of the cylindrical body (left side in the figure) is utilized by utilizing the suction force of the fan 101 rotating in synchronization with the rotation of the cylindrical body 10, and the air flow in the cylindrical body 10 in which the irradiation object 1 is stored. And the ozone 50 stored in the cylindrical body 10 is swept to the right. Then, the ozone 50 discharged outside the cylinder 10 in the electron beam irradiation area is adsorbed by the ozone adsorber 103, and only the clean air can be discharged outside the apparatus.

[0009] However, in the prior art, a fan must be provided for each of the cylinders that store the irradiation object.
Further, in order to secure a predetermined dose ratio to the irradiation object, the V-shaped support 102 must be provided with a cylindrical rotating means such as a driving rotary roller, which complicates the device configuration.

In view of the above technical problems, the present invention provides a high energy electron beam irradiation apparatus mainly used for sterilization, which has a simple structure and can locally and effectively remove ozone in the electron beam irradiation area. Aim.

[0011]

According to the first aspect of the present invention,
A high-energy electron beam irradiation apparatus having a suction opening facing the irradiation area in order to irradiate the three-dimensional object with a high-energy electron beam and remove ozone generated in the irradiation area, The suction opening is formed in a hood shape, specifically, a range hood shape, and the hood-shaped suction opening portion is disposed in a space above the electron beam irradiation area,
It is characterized in that the ozone can be locally and efficiently sucked by utilizing the upward airflow generated in the irradiation area.

As described above, an electron beam irradiator used for sterilizing a three-dimensional object is provided with an electron beam permeable film stretched over an electron beam irradiation window, and an electron beam permeable film is provided around the electron beam permeable film. It is configured to be held and fixed by a flange-like mounting flange. In such an electron beam irradiating apparatus for sterilization, the electron beam reacts with oxygen in the air after passing through the electron beam permeable film to generate ozone, but the electron beam after passing through the electron beam permeable film generates a large amount of heat energy. Then, a rising airflow is generated by the temperature rise by the heat energy. On the other hand, since ozone has a specific gravity 1.5 times or more heavier than air, a range hood-shaped ozone suction device is provided below the electron beam irradiation area as shown in the related art. Ozone could not be effectively sucked by the ozone suction device of (1).

Accordingly, in the present invention, the ozone suction opening in the form of a range hood is provided above the rising air flow, so that the ozone during operation can be effectively sucked and captured in accordance with the rising air flow.

However, heat energy is generated in front of the electron beam permeable membrane during operation, in other words, an ascending air current is generated only during operation. When operation is stopped, ozone has a specific gravity of 1.5 times or more than air. It sinks down gradually because of its weight.

According to the third aspect of the present invention, the suction opening is provided in the upper space and the lower space of the electron beam irradiation area, respectively. It is characterized in that ozone is sucked from the section, and when the electron beam irradiation operation is stopped, residual ozone can be sucked from a suction opening arranged in a space below the irradiation area.

According to this invention, it is possible to suck ozone riding on the ascending airflow by the upper suction device during the operation, and residual ozone by the lower suction opening after the operation is stopped, thereby almost 100%. The ozone suction efficiency was obtained.

In the case of the present apparatus, it is preferable that the opening area of the hood-shaped suction opening provided above is extended from the electron beam irradiation surface to a beam stop position located on the back side of the irradiation object. Further, the hood cross-section width may be widened toward the downstream, specifically, fan-shaped, or widened in accordance with the electron beam diffusion direction.

In still another embodiment of the present invention, the irradiation film
A permeable membrane cooling nozzle is arranged at a position on the side of the electron beam permeable membrane forming the (window) so that the surface of the permeable membrane is air-cooled by the air flow injected from the nozzle, and the nozzle mounting position A suction opening for suction by negative pressure is provided in the vicinity of the mounting flange of the electron beam permeable membrane on the side facing the surface, so that ozone generated on the surface of the permeable membrane can be supplemented by the suction opening before being diffused. And

Since the ozone suction opening for suction is provided near the mounting flange of the electron beam permeable film on the side facing the nozzle mounting position, ozone generated on the surface of the electron beam permeable film is diffused. In addition to the fact that the air can be effectively supplemented in advance, the cold air flow from the nozzle can also be sucked together at the suction opening, so that the upward air flow to the hood-shaped suction portion disposed above the irradiation area is not disturbed.

In this case, preferably, the mounting flange protruding portion located on the side facing the nozzle is formed with an inclined or curved guide surface along the nozzle blowing direction toward the suction opening.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

FIGS. 1 and 2 show a beam scanning type electron beam irradiation apparatus for sterilization according to an embodiment of the present invention. In FIG. 1, reference numeral 30 denotes an electron beam for generating a high energy electron beam (beam) 8. An electron beam accelerating unit for generating / accelerating, for example, an electron gun for emitting an electron beam, an acceleration tube for accelerating the electron beam emitted from the electron gun so as to have a predetermined energy, and And a klystron that supplies microwave energy to accelerate the energy. The accelerated electron beam is guided to a converging electromagnet (beam stop lens) 32 through a cylindrical beam guide tube 31, and converges the electron beam in the diametric direction, in other words, the beam is stopped down, and the diameter of the beam is reduced. To increase energy density.

The converging electron beam, which has been densified by the converging electromagnet 32, is introduced into an irradiation horn 34 in the shape of a truncated flat pyramid which is expanded in the beam scanning direction as it goes to the front.
The irradiation horn 34 is provided with a scanning electromagnet 35 on the entrance side,
In addition, a rectangular slit-shaped irradiation window is provided on the front surface, and the irradiation window is sealed with an electron beam transmitting film 36 such as a thin titanium film of about several 100 μm, and the inside is maintained in a vacuum space. That is, the electron beam transmitting film 36 is provided with a flat pyramid-shaped truncated pyramid-shaped flange 37 on its outer periphery so as to be in close contact with the front surface of the flat horn-shaped pyramid-shaped irradiation horn 34 via packing. Tighten and seal with screws.

The convergent beam introduced into the irradiation horn 34 is deflected and scanned at a predetermined deflection angle and deflection frequency (scanning frequency) by the scanning electromagnet 35. When the deflection scanning is performed, the beam scanning is performed. In order to control the speed, in other words, the angular velocity, a control signal for controlling the voltage applied to the scanning electromagnet 35 is taken in from the scanning electromagnet controller. The scanning electron beam 8 that has been deflected and scanned while controlling the angular velocity covers the entire width of the irradiation target 1 while scanning in the base line direction of the irradiation target 1 through the irradiation horn 34 having a flat truncated pyramid shape and the electron beam transmitting film 36. Irradiation to perform a predetermined sterilization operation.

The object to be illuminated in the present embodiment is one in which medical equipment and the like are housed in a rectangular carton case, and the objects to be illuminated 1 are arranged in a line along the conveying direction of the irradiation conveyor 2. Then, the irradiation horn 3 is sandwiched by the irradiation object 1.
The beam stop 4 is installed on the opposite side of the beam stop 4. The beam stop 4 is made of a metal having a large atomic number, for example, a tungsten plate or a stainless plate plated with gold, and has a fear of generating heat by absorption of an electron beam. 4a to add a cooling function.

The irradiation conveyor 2 uses a chain conveyor so that an air flow passes from below to above. Then, a range hood-shaped suction opening 43 is arranged in a space above the position facing the electron beam irradiation area, and a suction 44 and an intake blower are connected to the suction opening 43 to reduce the upward airflow generated in the irradiation area. The ozone can be sucked by utilizing it.
The hood-shaped suction opening 43 preferably has an opening area extending from the electron beam irradiation surface to a beam stop 4 located on the back side of the object to be irradiated. At the same time, the shape may be widened toward the downstream, specifically, fan-shaped, or widened.

A cooling nozzle 41 is provided below the flange 37 supporting the electron beam transmitting film 36.
The surface of the electron beam permeable film is configured to be air-cooled by the air flow injected from the nozzle 41, and is sucked by the negative pressure of the first suction 43 on the side opposite to the nozzle mounting position, in other words, near the upper portion of the flange. A semi-circular suction catcher 42 is provided to prevent the ozone generated on the surface of the permeable membrane 36 from diffusing.
2 so that it can be captured.

Although the flange 37 is formed in a rectangular cross section because of the necessity of screwing, the upper inner wall side of the mounting flange located on the side facing the nozzle 41 faces the catcher 42 from the nozzle blowing direction. An inclined or curved guide surface 38 is formed. A hood 45 sucked by the second suction 44B is attached below the irradiation conveyor 2, and the first and second suction
4, 44B are configured so that the first suction 44 operates during the electron beam irradiation operation in conjunction with the drive control circuit 5 of the electron beam irradiation device 3, and the second suction 44B operates for a predetermined time after stopping. ing. Also, as shown in FIG. 2 without providing a plurality of suctions 44 and 44B, switching is performed by a three-way valve 49 and shared by one suction 44, or a damper 4 is provided.
The opening degree may be adjusted and controlled by 9a and 49b. Further, the suction opening 45 provided below may be provided only below the chain-shaped conveyor 2.

Next, the operation of the embodiment will be described. First, when the electron beam operation starts, the electron beam permeable membrane 3 is opened.
The electron beam irradiating device is irradiated with an electron beam from the electron beam irradiating device 6 and enters the electron beam irradiating area while transporting the irradiating conveyor 2 in a state where the object to be irradiated 1 is installed vertically on the chain-shaped irradiating conveyor 2. 3 irradiates the object 1 with an electron beam having an energy of 10 MeV. As a result, the object 1 is sterilized while securing a predetermined dose.

In conjunction with the start of the operation, the drive control circuit 5 drives and rotates the suctions 44 and 44B, and when the electron beam is being irradiated, a cooling air is blown out from the cooling nozzle 41 and the electron beam irradiation is performed. The electron beam transmitting film 36 heated by the above is always cooled. At this time, the semicircular suction opening 4 sucked by the suction 44 near the mounting flange 37 of the electron beam transmitting film on the side facing the nozzle mounting position.
Since ozone 2 is provided, ozone generated on the surface of the electron beam permeable film 36 can be effectively trapped before being diffused, and the cold air flow from the nozzle 41 can be sucked together with the suction opening 42. Therefore, the upward airflow to the range hood-shaped suction opening 43 arranged above the irradiation area is not disturbed.

The ozone 50 generated in the irradiation area by the electron beam generates an ascending airflow in the irradiation area due to the thermal energy of the electron beam, but is attracted to drive the first suction 44 above the irradiation area. Ozone riding on the ascending airflow is sucked by the range hood suction opening 43 where a force is generated. Then, when the operation of the electron beam irradiation unit 3 is stopped, the drive control circuit 5 of the suctions 44 and 44B stops driving of the first suction 44 and drives the second suction 44B. (In the case of FIG. 2, switching control of the three-way valve or adjustment of the opening of the damper)

As a result, when the operation is stopped, the specific gravity of the ozone is 1.5 times or more greater than that of the air, so that the ozone gradually sinks downward. However, the suction force of the lower sub-hood-shaped suction opening 45 acts, and after the operation is stopped. Is the lower sub-hood-shaped suction opening 4
5, the residual ozone could be sucked, whereby an ozone suction efficiency of almost 100% as a whole was obtained.

[0033]

As described above, according to the present invention, it is possible to provide a high energy electron beam irradiation apparatus which has a simple structure and can effectively remove ozone in the electron beam irradiation area.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an electron beam irradiation device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating an electron beam irradiation apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic view showing an electron beam irradiation apparatus according to the prior application.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Irradiation object 2 Irradiation conveyor 3 Electron beam irradiation part 4 Beam stop 36 Electron beam transmission film 37 Flange 38 Guide surface 41 Cooling nozzle 42 Suction catcher 43 Suction opening 44 First suction 44B Second suction 45 Sub food hood shape Suction opening

Claims (5)

[Claims] 1. A high-energy electron, which is provided with a suction opening facing the irradiation area in order to irradiate a three-dimensional object with a high-energy electron beam and remove ozone generated in the irradiation area. In the electron beam irradiation apparatus, the suction opening is formed in a hood shape, and the hood-shaped suction opening is disposed in a space above the electron beam irradiation area, and the ascending opening is generated by using an ascending airflow generated in the irradiation area. A high-energy electron beam irradiation apparatus characterized in that ozone can be locally and efficiently sucked. 2. The high-energy electron beam irradiation apparatus according to claim 1, wherein the opening area of the hood-shaped suction opening extends from the electron beam irradiation surface to a beam stop position located on the back side of the irradiation object. High energy electron beam irradiation equipment characterized by the following. 3. A high-energy electron beam which is provided with a suction opening facing the irradiation area for irradiating a three-dimensional object with a high-energy electron beam and removing ozone generated in the irradiation area. In the electron beam irradiation apparatus, the suction opening is disposed in an upper space and a lower space of the electron beam irradiation area, respectively. During the electron beam irradiation operation, ozone is suctioned from the suction opening provided in the upper space, A high-energy electron beam irradiation apparatus characterized in that when the beam irradiation operation is stopped, residual ozone can be sucked from a suction opening arranged in a space below the irradiation area. 4. In order to irradiate a high-energy electron beam to a three-dimensional object to be irradiated, an electron beam permeable film is stretched over an electron beam irradiation window portion, and a periphery of the electron beam permeable film is mounted in a flange shape. In the high-energy electron beam irradiation device held and fixed by a flange, a permeable membrane cooling nozzle is disposed at a position lateral to the electron beam permeable membrane, and a surface of the permeable membrane is air-cooled by an air flow injected from the nozzle. And a suction opening for suction by negative pressure is provided near the electron beam permeable membrane mounting flange on the side facing the nozzle mounting position, and the ozone generated on the permeable membrane surface is diffused before ozone is diffused. A high-energy electron beam irradiation apparatus characterized in that it can be supplemented by: 5. An inclined or curved guide surface extending from a nozzle spraying direction to a suction opening is formed on a mounting flange protruding portion located on a side facing the nozzle. High energy electron beam irradiation equipment.