JP2003028998A - Small quantity particle batch process system used for electron beam irradiation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small processing apparatus capable of automatic operation for sterilizing with electron beam, particle such as grains. SOLUTION: A rotary valve is attached to a hopper which throws particle to be processed in an X-ray shielding body (box), and inside the X-ray shield (box), a carriage mechanism, stirring mechanism and electron beam irradiation device are placed, and an outlet is provided next to the stirring mechanism. A constant amount of particles to be processed is put in the box from the rotary valve, and carried with the carriage mechanism to the stirring mechanism, and a cylindrical vibration plate 16 is vibrated in horizontal directions here to cause the particles to turn and to irradiate with electron beam. After the processing, the particle is extracted from the outlet by inclining the cylindrical plate 16.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for sterilizing fine particles such as grains with an electron beam.
An electron beam irradiation apparatus is an apparatus that generates thermoelectrons inside a vacuum chamber, accelerates the electrons by a high voltage, takes out an electron beam from the irradiation window to the atmosphere, and irradiates the object to be processed. Therefore, the electron beam irradiation apparatus has a vacuum chamber, a filament, a filament power supply, a high-voltage power supply for acceleration, an acceleration tube, an irradiation window, a transfer device, a shielding mechanism, and the like. Two types of electron beam irradiation devices are manufactured according to the difference in acceleration voltage. When the accelerating voltage is as high as 3 MeV to 500 keV, the accelerating distance must be increased, so that the accelerating tube is long and a scanning tube is provided following the accelerating tube. The scanning tube is a triangular-shaped vacuum vessel with a widened lower part, and a coil is provided on the upper part. An alternating current is applied to the coil to form an alternating magnetic field, which has the effect of oscillating the beam left, right, front and back. When the acceleration voltage is high, the beam is narrowed narrowly, but the object to be processed can be widely irradiated with the electron beam by being scanned in the left-right direction and the front-back direction by the scanning tube. When the accelerating voltage is lower than 500 keV, an accelerating tube is not required, and the accelerating may be performed between the filament and the irradiation window. Thus, a filament is provided inside the cylindrical vacuum chamber, and thermoelectrons are accelerated between the irradiation window which is an opening of the vacuum chamber, and an electron beam is extracted through the irradiation window. This is called a non-scanning type (area type). Since the energy is low, the accelerating power supply can be small, and there is no scanning tube because scanning is not performed. The device can be smaller than the scanning type. [0004] In any of the apparatuses, a metal window foil made of titanium, Al, or the like is provided on the irradiation window. Window foil has the function of blocking the vacuum and the atmosphere. Atmospheric pressure is applied above and below the window foil. Electron beams lose a great deal of power as they pass through the window foil. The window foil is thereby heated. The window foil is cooled by cooling water and cooling air to remove heat. An appropriate acceleration voltage is determined according to the purpose of the electron beam irradiation, the state of the target object, the air path (flying distance in the air), and the like. The apparatus on the vacuum side and the high pressure side of the electron beam irradiation apparatus is as described above. On the atmospheric pressure side below the irradiation window, a transport mechanism for transporting an object to be processed and a housing (a casing) surrounding the transport mechanism. Shielding mechanism). It is necessary to enclose the case because an X-ray is generated by the electron beam. A thick metal shielding structure (housing) is required to prevent X-rays. Shields are provided inside so as to prevent X-rays from leaking from the entrance and the exit, so that the X-rays are blocked in multiple layers. [0006] Further, X-rays oxidize oxygen in the air to produce ozone. If the ozone odor does not adhere to the object, a nitrogen gas or a rare gas is flowed from the downstream side to the upstream side of the irradiation window in order to eliminate oxygen. Then, since ozone cannot be generated, the problem that an ozone odor adheres to the object to be treated is solved. A transport mechanism transports the workpiece inside the housing. The object to be processed is transported by a transport mechanism along a route of an entrance, an irradiation window, and an exit. Conventionally, the crosslinking reaction of the electric wire coating, the curing of the coating film,
The object to be processed, such as the strengthening of the printed matter surface and the sterilization of medical equipment, was a fixed solid. Since the surface to be irradiated with an electron beam is fixed in a fixed form, the endless conveyor is used as a transport mechanism, and the object to be processed is placed on it and transported so that it can be exposed to one-sided electron beam irradiation through the irradiation window. Things were good. [0008] In order to sterilize grains such as grains by irradiating an electron beam, only the surface layer must be thinly treated with an electron beam. When the electron beam penetrates into the grain, the quality of proteins and the like inside the grain deteriorates, and the flavor drops. Therefore, in the case of particulate matter, the electron beam energy must be lowered and the electron beam must be applied only to the surface. If the purpose is to sterilize microscopic particles such as grains, a static transport mechanism such as an endless conveyor that cannot roll and rotate the particles is useless. Since the electron beam is irradiated from one side, the transport mechanism itself must roll and spin the object to be processed so that all surfaces face the electron beam irradiation direction. But this is not easy. One candidate is to use a vibrating conveyor that feeds a workpiece while vibrating it. It can process continuously. The other is suitable for batch processing, and a stirring vessel is provided between the irradiation window of the electron beam irradiation apparatus and the supply portion of the object to be processed so as to be able to move forward and backward. It is a movable stirring vessel. (1) Japanese Patent Application Laid-Open No. H11-337700 "Electron Beam Irradiation Apparatus", which is available to the applicant of the present invention, has a path including a workpiece input hopper, a transport path and a workpiece discharge hopper. We proposed an electron beam irradiator that attaches a vibration mechanism to the metal cylinder as a sealed space, vibrates the metal cylinder obliquely up and down, so that the particles can be raised, rolled, and advanced while rotating. ing. The vibrating conveyor itself is well known, but there has never been a structure in which it is inserted into an electron beam irradiation device. Since the vibration of the vibrating conveyor is obliquely up and down and asymmetrically vibrated, even if the vibrating conveyor trough is horizontal, the granular material soars and moves forward while rolling. This is a dynamic transport mode, and has an advantageous effect that not only the object to be processed is sent to the front but also the electron beam hits the entire surface by rotating. In addition, since a tubular metal trough can be sealed to allow nitrogen gas to flow, ozone can be prevented from being generated. Nitrogen gas leaks from the processing object input hopper and the processing object discharge hopper, but the pressure of the nitrogen gas can be adjusted by adjusting the charging and discharging speed. This is suitable for continuous processing because it can be continuously transported, and is suitable for large-volume processing. (2) Japanese Patent Application Laid-Open No. 2000-106855, entitled "Rolling device and sterilizing method for granules", proposes a structure suitable for batch processing instead of continuous processing. A rotating shaft is set up in the middle of a large circular dish-shaped metal container, and four thin stirring arms are attached to the rotating shaft to slowly rotate the stirring arm. A granular object to be treated, such as grain, is placed in a dish-shaped metal container. When the rotating shaft is rotated by the motor, the stirring arm rakes on the grain processing object, so that the processing object is stirred, and sometimes it is reversed and rotated. A rail is provided from the outside (starting point) directly below the irradiation window (end point) of the electron beam irradiation apparatus, and the above-mentioned dish-shaped stirring vessel is placed on the rail, and the starting point (the object to be treated is charged). It is possible to reciprocate between the discharge point) and the end point (just below the irradiation window). Externally, a granular object to be treated is put in a stirring vessel, and is run on a rail to be sent directly below an irradiation window of an electron beam irradiation apparatus, and is irradiated with an electron beam while rotating a stirring arm. Then, the object to be processed is sometimes rotated by the stirring arm, so that the entire surface is irradiated with the electron beam. Since this is a batch process, it is suitable for a small amount of processing. [0014] Two conventional examples have been described for the purpose of rotating a granular material and uniformly applying an electron beam to the entire surface. The conventional example (1) using a vibrating conveyor is capable of continuously irradiating an object to be processed with an electron beam and is suitable for mass processing. However, since the vibrating conveyor is built in the shielding mechanism of the electron beam irradiation device, the entire electron beam irradiation device becomes large. Since it is a large-sized device, the device cost is large. The cost for operation is also high, and it is not suitable for processing when the amount of the object to be processed is small.
As a result, when used for sterilizing grains and the like, there is a disadvantage that the processing cost becomes too high. The prior art (2), in which an object to be treated is put in a stirring vessel, is fed under an irradiation window of an electron beam irradiation device, and emits an electron beam while rotating a stirring arm, is a small device. Equipment cost can be reduced. There is an advantage that the cost does not increase even when the processing amount is small. However, since the object to be processed is manually put into the container and the object to be processed is manually removed from the container, automation cannot be performed. The operation of inserting and extracting the container into and from the electron beam irradiation apparatus is performed by a worker, which is a troublesome operation. In addition, since humans are involved in removing the sterilized object, there is a possibility that the object will be newly contaminated at that time. It is a first object of the present invention to provide an apparatus capable of reducing the apparatus cost and automating the charging and removing of the object to be processed into and from the container. It is a second object of the present invention to provide an apparatus capable of performing low-cost processing so that processing cost does not increase even in a small amount of processing. It is a third object of the present invention to provide an apparatus which cuts out a granular material as an object to be treated by a fixed amount and automatically supplies the cut-out object to a stirring vessel so as to be able to carry out a quantitative treatment and recover. According to the present invention, there is provided a batch processing apparatus for an electron beam irradiation apparatus, in which a rotary valve is installed at a workpiece input port of a housing of the electron beam irradiation apparatus, and a rotary valve is provided inside the housing. A transport mechanism that transports the granular workpiece and a stirring mechanism that is provided immediately below the electron beam irradiation window following the transport mechanism are provided, and a mechanism that automatically removes the workpiece from the stirring mechanism to the outside of the housing is provided. ing. The objects to be processed are introduced into the housing by a fixed amount through the rotary valve. The object to be processed advances inside the housing by the transport mechanism and is sent to the stirring mechanism. The electron beam is irradiated while the granular material rolls and rotates by the stirring mechanism. The processed object after the electron beam processing is taken out of the housing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a stirring mechanism, a cylindrical vibrating plate is moved right and left to roll and rotate a granular material left and right.
The rolling rotation becomes more active than in the conventional example (2), in which the stick rotating the dish-shaped container scratches the surface. When the treatment is over, the cylindrical diaphragm of the stirring mechanism can be tilted to flow the granules into the discharge port. An air cylinder, for example, can be used as a mechanism for holding the cylindrical diaphragm in the forwardly inclined posture and the horizontal posture. A hydraulic cylinder may be used. It is also possible to move the cylindrical diaphragm by rotating the motor output at a reduced speed. With respect to the stirring mechanism, if the cylindrical diaphragm vibrates right and left just below the irradiation window, the air pulse (the flight distance of the electron beam in the air) can be shortened. The air pulse can be shortened and the electron beam energy loss can be reduced as compared with the conventional example (2). As the transport mechanism, various transport mechanisms such as an electromagnetic feeder, an endless orbiting conveyor, and a vibrating conveyor can be used. In the conventional example (2) in which the granules are manually charged into a stirring vessel, the stirring vessel is charged into the electron beam irradiation apparatus, and then manually carried out after the treatment, the air needs to be replaced with nitrogen every time the carrying-in is performed. However, since the granules are automatically charged, transported, and discharged, no air enters the housing, and there is no need for air replacement. Since a fixed amount is measured by a rotary valve provided in the charging hopper, a batch sterilization system with constant quality can be realized. FIG. 1 is a vertical sectional side view of a stirring device of an electron beam irradiation apparatus according to an embodiment of the present invention, and FIG. 2 is a vertical sectional front view of the same. The box-shaped X-ray shield 1 is a thick metal casing that covers the entire device so that X-rays do not leak to the outside. An area type (non-scanning type) electron beam irradiation device 2 that generates an electron beam is accommodated above the inside of the X-ray shield 1. The area type electron beam irradiation apparatus 2 has a cylindrical shield 3 inside a cylindrical vacuum chamber. The shield 3 has a plurality of filaments 4 inside. An alternating current flows through the filament 4 by a filament power supply. At the same time, a negative high voltage serving as an acceleration voltage is applied to the filament 4. An opening directly below the vacuum chamber becomes an irradiation window 5. A window foil 6 is provided on the irradiation window 5. A negative voltage is applied to the filament 4 to heat the filament 4 to generate thermoelectrons. Thermoelectrons are accelerated between negative and ground voltages.
The electron beam 7 is accelerated to become a beam-like electron beam 7 and passes through the window foil 6 of the irradiation window 5 and exits to the atmosphere. On the upper part of the X-ray shield 1, an inverted conical input hopper 8 for inputting a granular object to be processed is provided.
A rotary valve 9 is provided near the top of the cone of the input hopper 8.
Is provided. This means that a disk with several compartments is rotating and passes a certain amount of granular material. This ensures quantitativeness. Subsequent to the rotary valve 9, a supply pipe 10 for an object to be processed is provided vertically through the upper wall of the X-ray shield 1. An electromagnetic feeder 11 is provided which extends laterally from immediately below the opening at the lower end of the supply pipe 10. This is to vibrate the flat transport surface 12 by the action of the alternating magnetic field, and transport the object on it in one direction. This simply transports the object from the supply pipe 10 to a stirring mechanism provided near the irradiation window of the electron beam irradiation apparatus.
It is not necessary to agitate the workpiece by rotational disturbance. So it is not limited to electromagnetic feeders. The transport mechanism may be an endless orbiting conveyor. A stirring mechanism 14 is provided at the end of the transport mechanism, which is located immediately below the irradiation window 5 of the electron beam irradiation apparatus 2. It is a mechanism for rolling the object to be processed, which is the granules 13, and for irradiating the entire surface with an electron beam. The stirring mechanism 14 includes a box-shaped lower frame 15 and a cylindrical diaphragm 16 provided above the lower frame 15. The cylindrical diaphragm 16 is supported by bearings (not shown) and can be repeatedly moved right and left. This is a large motion centered on the center of curvature of the cylinder. The shape is part of a cylinder to allow such movement. Immediately below the cylindrical diaphragm 16 is a lower arm 17, and joints 18 and 19 are connected to the lower arm 17.
To be fixed. The joints 18 and 19 support the bearing, and the bearing guides the left-right vibration of the cylindrical diaphragm 16. The rear end of the lower arm 17 is rotatably supported on the lower frame 15 by a pivot pin 20. The front end of the lower arm 17 is a movable support point 21. The tip of the rod 23 of the air cylinder 22 is attached to the support point 21 by a pin. The tail of the air cylinder 22 is fixed to a part of the lower frame 15 by a pin 24. When the rod 23 of the air cylinder 22 is extended, the cylindrical diaphragm 16 assumes a horizontal posture as shown by a solid line in FIG. The cylindrical diaphragm 16 vibrates left and right repeatedly by a motor 25 and a rack and pinion mechanism 26. That is, a curved rack is attached to the back surface of the cylindrical diaphragm 16, and the pinion is engaged with the rack. The rotation of the motor 25 is reduced to rotate the pinion. When the motor 25 rotates in the forward and reverse directions, the cylindrical diaphragm 16 also moves left and right. The radius of curvature of the cylindrical diaphragm 16 is R, and the module of the rack is m. Assuming that the central angle of the spread of the cylindrical diaphragm 16 is Θ, the number M of teeth of the rack is M = ΘR /
given by m. The module of the pinion is m and is the same as the module of the rack. Assuming that the number of teeth of the pinion is z, the reduction ratio by the combination of the pinion and the rack is mz / 2πR. There is a speed reduction mechanism between the motor and the pinion. If the speed reduction ratio is 1 / r, the overall speed reduction ratio is mz / 2πRr. The purpose of vibrating the cylindrical diaphragm 16 is not to stir the granules. Instead, it is to roll the granules to give a chance that all surfaces face the direction of the electron beam. Although not shown, a gas pipe for supplying a nitrogen gas or a rare gas is provided inside the housing 1. An outlet of a gas pipe is provided near the irradiation window 5, and a gas such as nitrogen or Ar is blown to the electron beam irradiation object. This is to prevent ozone from being generated by X-rays. Separately, a cooling mechanism (water cooling, air cooling) for cooling the cylindrical diaphragm 16 is provided, but is not shown. When the rod 23 of the air cylinder 22 is retracted, the cylindrical diaphragm 16 is inclined forward as shown by the dashed line in FIG. A discharge port 27 for the object to be processed is provided immediately in front of the forwardly inclined cylindrical diaphragm 16. When the cylindrical diaphragm 16 is tilted forward, the cylindrical diaphragm 16
The particles 13 on the rolls are rolled and taken out from the discharge port 27 to the outside. The operation of the above configuration will be described. A granular (grain) material 13 to be sterilized is charged into the charging hopper 8. Rotary valve 9 rotates and feed pipe 1
0. This enters the inside of the housing (X-ray shield) 1 and falls on the transport surface 12 of the electromagnetic feeder 11. The granular material 13 (object to be processed) moves forward by the vibration of the electromagnetic feeder. Then, it reaches the cylindrical diaphragm 16 of the stirring mechanism 14. When a single granular material 13 rides on the cylindrical diaphragm 16, the filament 4 of the electron beam irradiation device 2 is turned on to generate the electron beam 7. The electron beam 7 travels through the vacuum chamber, passes through the window foil 6 of the irradiation window 5, and hits the granules 13 on the cylindrical diaphragm 16. The cylindrical diaphragm 16 includes a motor 25 and a rack and pinion 26.
Performs a left-right vibration motion about the center of curvature of the cylindrical surface. Since the cylindrical diaphragm 16 holds the horizontal posture, the particles hardly move back and forth but move right and left. FIG. 3 is a plan view of the cylindrical diaphragm 16.
This shows a state in which it is shifted to the left from the fixed center line m. The granules are carried to the left, but the left half is inclined rightward, so the granules roll to the right. FIG. 4 shows a state shifted to the right from the fixed center line. The granules are moved to the right, but the right half becomes a left-facing slope, and the granules begin to roll to the left. When the cylindrical diaphragm 16 moves left and right in this manner, the particles 1 move in the opposite direction.
3 tries to roll. With the movement of the cylindrical diaphragm 16,
Since the granules 13 roll or jump, the surface facing upward changes. Therefore, the electron beam hits the surface of the granules thinly and uniformly, and is sterilized. After a certain period of time, the electron beam irradiation is stopped. The horizontal vibration of the cylindrical diaphragm is also stopped. Air cylinder 2
The second rod 23 is retracted. The front end of the cylindrical diaphragm 16 is lowered to assume an inclined posture as shown by a dashed line in FIG. The sterilized particles 13 slide down and are taken out of the housing 1 (X-ray shield) through the outlet 27. When the processing for one time is completed, the rotary valve 9 is operated to drop the next time for the granules 13 onto the electromagnetic feeder 11. The following processing is exactly the same as the previous processing. Such a batch sterilization process is repeated. According to the present invention, the particles can be exposed to an electron beam while rolling and rotating the particles. Sterilization treatment of grains such as wheat with an electron beam can be performed. Batch processing is performed by a fixed amount by a rotary valve. Since the processing amount and the processing time are constant, the effect of the sterilization treatment is constant. Since the electron beam energy may be low, a small electron beam irradiation device can be used. It is not a large device as in the conventional example (1) using a vibrating conveyor. The device is smaller, cheaper and easier to use. However, the processing time may be shorter because the rolling performance of the granules is superior to that of the conventional example (2) in which the granules are intermittently turned over with a stirring rod. As in the conventional example (2), it is troublesome to put the stirring container on a rail, pull it out, push it in, or manually operate it. In each case, the air must be replaced with nitrogen, which is inefficient. The present invention does not require manual operation and often does not require nitrogen replacement. The supply, processing and discharge of the granules can be performed automatically. Good work efficiency. There is a possibility that the particles will be contaminated if an operator works manually. However, since the present invention uses no manual operation, there is no concern about the contamination. This is also superior to the conventional example (2).

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical side view of a batch processing apparatus used for an electron beam irradiation apparatus according to an embodiment of the present invention. FIG. 2 is a vertical sectional front view of a batch processing apparatus used in the electron beam irradiation apparatus according to the embodiment of the present invention. FIG. 3 is a plan view of the cylindrical diaphragm when the cylindrical diaphragm is on the left in the batch processing apparatus of the present invention. FIG. 4 is a plan view of the cylindrical diaphragm in the case where the cylindrical diaphragm is on the right in the batch processing apparatus of the present invention. [Description of Signs] 1 X-ray shield 2 Electron beam irradiation device 3 Shield 4 Filament 5 Irradiation window 6 Window foil 7 Electron beam 8 Input hopper 9 Rotary valve 10 Supply pipe 11 Electromagnetic feeder 12 Transfer surface 13 Granules (object to be processed) 14) Stirring mechanism 15 Lower frame 16 Cylindrical diaphragm 17 Lower arm 18 Joint 19 Joint 20 Pivot pin 21 Support point 22 Air cylinder 23 Rod 24 Pin 25 Motor 26 Rack and pinion mechanism 27 Discharge port

Claims (1)

Claims: 1. An electron beam irradiation device 2 for generating an electron beam,
A stirring mechanism for rolling the granules by vibrating a cylindrical diaphragm 16 provided below the electron beam irradiation window 5 of the electron beam irradiation device to the left and right, and a charging hopper for charging a granular object to be processed. 8 and a rotary valve 9 provided in the charging hopper
A transport mechanism for transporting the granular workpiece that has passed through the rotary valve to the stirring mechanism 14, a mechanism for holding the cylindrical diaphragm 16 in a horizontal posture or a forward inclined posture, and a cylindrical diaphragm 1
It comprises a discharge port 27 provided at a position where the granular material flows from the cylindrical diaphragm 16 when the particle 6 is tilted forward, and an X-ray shield 1 which houses therein an electron beam irradiation device, a transport mechanism, and a stirring mechanism. A small batch processing system for use in electron beam irradiation equipment.