JP2007297068A - Method of irradiating open container with electron beams, and device for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of irradiating open containers with electron beams, according to which the overall surface of each open container having a neck portion is uniformly irradiated with electron beams during high-speed transfer operation, and to provide a device for use in the method. <P>SOLUTION: According to the method, when the open containers 1 each having the neck portion are sequentially transferred by a rotary transfer body 11, electron beams EB are emitted from an electron beam irradiation means 40 to irradiate the open containers 1 which are transferred in a negatively pressurized atmosphere, thereby carrying out sterilizing processing. During the electron beam irradiation, in order to mount an irradiation protective plate 4 in the vicinity of the neck portion of each open container, the device for use in the method is provided with an attaching/detaching mechanism 5. The attaching/detaching mechanism 5 is operable according to rotational movement of the rotary transfer body 11, and has the irradiation protective plate 4 mounted in the vicinity of the neck portion of the open container during the electron beam irradiation while has the irradiation protective plate removed after the electron beam iradiation. Further the device has a magnetic field deflecting means 8 for converging electron beams and a cooling means 9 arranged on the lower surface of the irradiation protective plate 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electron beam irradiation method and apparatus for an open container, and more particularly to an electron beam irradiation method for an open container suitable for sterilizing the inner and outer surfaces of an open container made of plastic and having a narrow neck with an electron beam, and the apparatus. Relates to the device.

  Recently, many plastic open containers are used for filling beverages, foods, medicines, and cosmetics. These open containers are sterilized by sterilizing the inside before filling the contents, and then the contents are filled and sealed. As for the sterilization treatment of the open container, it has been proposed to sterilize the inner and outer surfaces of the open container by using an electron beam instead of using a chemical that requires a large amount of equipment.

  In general, an open container having a narrow neck such as a PET bottle is transported at a high speed on the production line, and therefore, an electron beam irradiation apparatus having a large scale and poor energy efficiency cannot be incorporated into the bottle production line. . For this reason, it has been proposed to incorporate an electron beam irradiation apparatus for generating a low energy electron beam that is reduced in size and energy efficiency into the bottle production line.

  When this type of low energy electron beam irradiation apparatus is used, since an electron beam transmission effect cannot be expected, a magnetic field deflecting means or the like is used to uniformly irradiate the open container with an electron beam. However, in the case of an open container such as a plastic bottle with a narrow neck, an electron beam is introduced into the inside through the opening of the neck and the inner surface is irradiated. In such electron beam irradiation, the amount of electron beam entering from the opening of the neck of the opening container is small, and further, because of electron divergence in the electron transmitting material used for the electron beam generating means and the gas in the atmosphere to which the electron is irradiated, further Since the electron dose decreases, it is necessary to secure a certain irradiation time. However, if the irradiation time is lengthened, the narrow opening portion of the opening container and the so-called neck portion around the opening container are excessively irradiated with the electron beam, and the electron beam irradiation portion of the opening container is discolored or deformed in an extreme case. Can not withstand use.

  In order to improve this, for example, a 100 kV class electron beam generating means is used, and an electron beam irradiation section by this electron beam generating means is provided in the transfer path of the open container, and the open container continuously transported is an electron. It has been proposed that an electron absorption cooling mask is disposed above the neck of an open container to partially limit the irradiated electron beam when performing irradiation sterilization treatment with a line (see Patent Document 1).

  In addition, when performing electron beam irradiation in the production line, a mask member that is semi-transparent to the electron beam is attached to the neck of the open container that is close to the electron beam generating means and increases the electron beam irradiation dose. It has also been proposed to suppress the amount of electron beam irradiation in this portion and prevent alteration of the open container (see Patent Document 2).

Special table 2001-524056 JP-A-2005-249671

  However, in a soft drink production line using an open container such as a plastic bottle, the open containers are transported at a high speed of 600 bottles per minute. Irradiation will be performed. In a production line that continuously conveys such an open container at a high speed, when using a mask as in Patent Documents 1 and 2, a mask made of a thin metal or resin is used. The energy which is not transmitted is accumulated and becomes heat, and the mask may be deformed by this heat, and there is a problem that it cannot be easily applied to the continuous production line of the open container.

  An object of the present invention is to provide an electron beam irradiation method and apparatus for an open container that can sterilize by uniformly irradiating the entire surface of the open container having a neck with an electron beam during high-speed conveyance.

  The electron beam irradiation method for an open container according to the present invention continuously conveys an open container having a neck by a rotating transport body, and performs electron beam irradiation in a reduced-pressure atmosphere during transport of the open container during transport and the rotation. The irradiation protection plate attachment / detachment mechanism is operated in accordance with the rotational movement of the carrier, and the irradiation protection plate is mounted near the neck of the opening container while the electron beam is irradiated, and the irradiation protection plate is removed after the electron beam irradiation. It is characterized by doing.

  Further, the electron beam irradiation apparatus for an open container of the present invention includes a rotary transport body that continuously transports an open container having a neck, an electron beam irradiation means that emits an electron beam in a reduced-pressure atmosphere during the transport of the open container, The irradiation protection plate disposed near the neck of the open container, and the irradiation protection plate is supported by the rotary transport body, and is operated in accordance with the rotational movement of the rotary transport body to irradiate the irradiation protection plate with the electron beam. It is characterized in that it is equipped with an attachment / detachment mechanism that is mounted and removed after irradiation with an electron beam.

  Preferably, the irradiation protection plate is formed from a flat plate portion that is opaque to electron beams and a cylindrical portion that is inserted into the neck portion of the opening container, and provided with a magnetic field deflecting means for focusing the electron beam on the lower surface of the flat plate portion, It is characterized by comprising a cooling means.

  In the electron beam irradiation method for an open container according to the present invention, when an open container having a neck is irradiated with an electron beam, the irradiation protection plate can be easily attached and detached as the rotary carrier is rotated. Therefore, it can be used for a long period of time, and the entire surface including the neck portion of the open container can be efficiently sterilized by irradiation with an electron beam.

  In addition, when configured as the electron beam irradiation apparatus for an opening container of the present invention, the opening container is provided with an attaching / detaching mechanism that operates in accordance with the rotational movement of the rotary carrier and attaches / detaches the irradiation protection plate. It can be used by being easily incorporated into the transporting production line, and the electron beam irradiation of the open container can be effectively performed.

  In this invention, the opening container which has a neck part is continuously conveyed with a rotary conveyance body, and an electron beam is irradiated from an electron beam irradiation means with respect to the opening container currently conveyed in a pressure-reduced atmosphere. An irradiation protection plate disposed near the neck of the opening container is supported by the rotary transport body, and is operated along with the rotational movement of the rotary transport body to attach the irradiation protection plate during electron beam irradiation, and And an attachment / detachment mechanism for removal after electron beam irradiation.

  An electron beam irradiation apparatus for an open container to which the present invention is applied is shown in FIG. 1 (a), and is an example in which a plastic bottle is used as an open container having a neck. A front pressure adjusting tank 20 and a rear pressure adjusting tank 30 are disposed adjacent to the side surface of the irradiation processing tank 10 disposed in the center and are integrally connected. In each of these tanks 10, 20, and 30, rotationally transporting bodies 11, 21, and 31 that are rotated in synchronization with a drive mechanism as indicated by arrows are rotatably arranged. An annular conveyance path for sequentially conveying the open container 1 is formed. Therefore, in the production line of the open container 1, the pre-pressure adjusting tank 20 connected to the pre-processing line, the irradiation processing tank 10, and finally the post-pressure adjusting tank 30 connected to the post-processing line are sequentially arranged. .

  Each of the rotary transport bodies 11, 21, 31 is provided with a large number of holding mechanisms 2 that hold and transport the open container 1 on the outer surface at equal intervals. It is set as the structure which can be smoothly delivered in order with the open container 1 in the upright state between the rotation conveyance bodies 11, 21, and 31 in each tank 10, 20, and 30 until a processing line.

  The inside of the irradiation processing tank 10 is configured to have a pressure-resistant sealed structure for reducing the pressure inside, and a pipe 14 connected to an exhaust means including a vacuum evacuation device 13 is connected to the irradiation processing tank 10 to surround the open container 1 to be conveyed. The atmosphere is maintained at a predetermined negative pressure state. In addition, at least one electron beam generating means 40 for electron beams connected to a power source is provided in a portion corresponding to the transfer path serving as an electron beam irradiation chamber in the irradiation processing tank 10. Using this electron beam generating means 40, the irradiation container 10 is maintained in a negative pressure state, irradiated with an electron beam toward a transfer path serving as an electron beam irradiation chamber, and the transferred open container 1 is continuously provided. Thus, sterilization is performed.

  Since the electron beam generating means 40 is sterilized by irradiating the inner and outer surfaces of the open container 1 with an electron beam in a negative pressure atmosphere, an electron beam generating means 40 having an acceleration voltage of 150 kV or less with low energy can be used. If the inside of the irradiation processing tank 10 is in a decompressed state, the attenuation of the electron beam is greatly reduced, so even with a low-energy electron beam, the electron range (flight distance) becomes long, and the electron The amount of divergence of the line is small, and even the narrow open container 1 can effectively irradiate the inner surface with an electron beam.

  In order to effectively maintain the negative pressure state in the irradiation processing tank 10 so that the irradiation of the electron beam can be performed satisfactorily, it is connected to the pretreatment line side which is the opening container carry-in and the post-treatment line which is the carry-out side. The front pressure adjustment tank 20 and the rear pressure adjustment tank 30 are specially devised by the present invention. That is, partition walls 3 for separating the holding mechanisms 2 are provided on the rotary transport bodies 21 and 31 in the front pressure adjustment tank 20 and the rear pressure adjustment tank 30, respectively. Sometimes, a plurality of small compartments 22 and 32 are formed between the partition walls 3 on both sides of each holding mechanism 2 and the tank wall surface.

  Moreover, in order to depressurize the plurality of small sections 22 existing in the range where the open container 1 is moved from the position where the open container 1 is taken from the previous process line to the irradiation processing tank 10 on the side of the front pressure adjusting tank 20, a vacuum is applied to the wall surface in this range. A plurality of pipes 24 connected to the exhaust means including the exhaust device 23 are connected. As a result, the small section 22 in the range from the opening container 1 being carried into the front pressure adjustment tank 20 from the previous process line to the irradiation treatment tank 10 is a pressure adjustment range in which the state is from atmospheric pressure to a desired negative pressure. It can be managed effectively.

  Further, on the side of the rear pressure adjusting tank 30, in order to depressurize the small section 32 formed in the range in which the opening container 1 is moved from the irradiation processing tank 10 to the position of the post-process line, the vacuum exhaust is similarly applied to the wall surface in this range A plurality of pipes 34 connected to the exhaust means including the device 33 are connected. For this reason, the small section 32 in the range from the irradiation processing tank 10 to the post-process line of the post-pressure adjusting tank 30 until the open container 1 is carried out is reversely adjusted to a state from a desired negative pressure to an atmospheric pressure. It can be managed effectively as a range.

  The plurality of pipes 24 and 34 can be effectively decompressed by increasing the pipe diameter as they are closer to the irradiation treatment tank 10 or by increasing the number of pipes to be connected. The pressure change in the front pressure adjustment tank 20 and the rear pressure adjustment tank 30 can be smoothly performed. In addition, the range in which the small section 32 of the front pressure adjusting tank 20 or the rear pressure adjusting tank 30 is depressurized is opposite to the above as necessary, that is, in the front pressure adjusting tank 20, from the irradiation processing tank 10 to the front process line. Both the small section 32 in the moving range and the small section 32 in the range moving from the irradiation processing tank 10 to the post-process line in the rear pressure adjusting tank 30 can be decompressed by providing an exhaust means.

  Each partition 3 for forming the small sections 22 and 32 is provided so as to have a minute gap G between the outer walls of the tanks 20 and 30 as shown in FIG. A plurality of the partition walls 3 exist in each range from the irradiation treatment tank 10 to the front pressure adjustment tank 20 and the rear pressure adjustment tank 30 on the air release side. For this reason, the plurality of partition walls 3 have the same function as the labyrinth seal structure, and the flow resistance from the irradiation treatment tank 10 to the outside of the atmospheric pressure increases, so that the irradiation treatment can be performed without using a special seal or the like. The negative pressure state of the tank 10 can be maintained. As a matter of course, the capacity of the vacuum evacuation device 13 of the exhaust means provided in the irradiation processing tank 10 is set to allow for the amount of leakage, thereby maintaining the inside of the irradiation processing tank 10 within a predetermined negative pressure range. be able to.

  Moreover, the piping 16 from the clean air generator 15 provided with an appropriate filter is connected to the irradiation processing tank 10, the pre-pressure adjusting tank 20, and the post-pressure adjusting tank 30 using, for example, a dry pump, and the clean air is contained therein. Is configured to supply. Instead of the clean air generator 15, various gas supply devices that supply nitrogen gas, helium gas, or a mixed gas thereof can be connected in order to provide a gas atmosphere in which electron beam irradiation can be satisfactorily performed. .

  In the electron beam irradiation apparatus for an opening container having the above-described configuration, the opening container 1 fed into each of the front pressure adjustment tanks 20 in an upright state from the previous process line sequentially passes through the irradiation treatment tank 10 from the front pressure adjustment tank 20, Although it is carried out from the post-pressure adjusting tank 30 to the post-process line, it is sterilized by electron beam irradiation from the electron beam generating means 40 in the negative pressure atmosphere of the irradiation processing tank 10 partway. At this time, when the rotary carrier 21 in the front pressure adjustment tank 20 rotates in the clockwise direction, it is formed in a range closer to the irradiation treatment tank 10 from the position where it is taken into the front pressure adjustment tank 20 from the previous process line of the open container 1. The small compartment 22 holding the open container 30 inside is in a state where the pressure is gradually reduced from the atmospheric pressure by the exhaust means, and when it moves to the rotary carrier 11 in the irradiation processing tank 10, The negative pressure is almost the same.

  Conversely, the rotary carrier 31 in the rear pressure adjusting tank 30 rotates in the clockwise direction, and the opening container 1 is formed in a range approaching the discharge position from the irradiation processing tank 10 to the subsequent process line, and the opening container 30 is formed inside. In the small section 32 that holds the pressure, the exhaust means gradually approaches the atmospheric pressure from the negative pressure state in the irradiation processing tank 10, and the atmospheric pressure is reached when the open container 1 is discharged to the post-process line side. .

  Since the electron beam irradiation apparatus for an open container is configured as described above, the pressure management inside each tank can be appropriately and appropriately managed by the irradiation processing tank 10, the front pressure adjustment tank 20, and the rear pressure adjustment tank 30, so that the negative In the irradiation treatment tank 10 maintained at a pressure, the opening container 30 can be effectively sterilized with an electron beam using the low energy electron beam generating means 40.

  Furthermore, in this electron beam irradiation apparatus for open containers, the irradiation processing tank 10, the front pressure adjustment tank 20, and the rear pressure adjustment tank 30 are integrally connected, and each open container remains in an upright state with a rotary conveyance body inside each tank. Since it can be conveyed at high speed in order and is irradiated with an electron beam within an area provided in the irradiation treatment tank 10, the sterilization treatment of the open container incorporated in a production line for beverages or the like can be performed continuously.

  In the electron beam irradiation apparatus for an opening container of the present invention, as shown in FIG. 2, when the electron beam EB is irradiated from the electron beam generating means 40 to the opening container 1 having the neck portion being conveyed, the irradiation protection plate 4 is used as the opening container. It is arranged in the vicinity of the neck portion of this, thereby preventing excessive irradiation of the electron beam and effectively shielding the electron dose.

  The irradiation protection plate 4 is disposed on the rotary transport body 11 that does not hinder the transport of the open container 1 and is supported by the rotary transport body 11 via the attachment / detachment mechanism 5. In addition, the attachment / detachment mechanism 5 moves up and down as the rotary transport body 11 rotates, and the irradiation protection plate 4 is mounted near the neck of the opening container 1 during the electron beam irradiation and is removed after the electron beam irradiation. It is configured to do.

  In order to operate the attachment / detachment mechanism 5 in the vertical direction indicated by the arrow, for example, a guide guide 6 is provided on the outer surface of the rotary carrier 11, and one end of the attachment / detachment mechanism 5 is slidably arranged in this portion. In addition, a roller 7A and a cam-type guide rail 7B having an upper surface protruding in an arc shape are provided on the lower surface of the attaching / detaching mechanism 5 in combination. With these rollers 7A and guide rails 7B, the attachment / detachment mechanism 5 moves up and down as the rotary carrier 11 rotates, and the irradiation protection plate 4 is mounted near the neck of the opening container 1 during electron beam irradiation. The structure is such that it can be maintained and removed after electron beam irradiation.

  As shown in FIG. 3, the irradiation protection plate 4 is composed of a flat plate portion 4A provided with a small hole 4C and a hollow cylindrical portion 4B having a size capable of inserting a part or all of the neck portion of the opening container 1 at the upper end. It is integrally formed in a cylindrical shape having a portion. Since the flat plate portion 4A of the irradiation protection plate 4 generates heat when irradiated with an electron beam, a material having good thermal conductivity such as copper or aluminum is used, and the hollow cylindrical portion 4B has a plurality of holes or mesh shapes. By using a material having good electrothermal property or a material that transmits an electron beam, the electron dose to which the neck portion of the open container 1 is irradiated is made appropriate.

  Further, the irradiation protection plate 4 is fitted with a ring-shaped magnetic field deflecting means 8 made of a permanent magnet in the hollow cylindrical portion 4B on the lower surface. The magnetic field deflecting means 8 converges the electron beam from the electron beam generating means 40 so that the electron beam enters the opening container 1 having the neck from the small hole 4C, and the irradiation sterilization treatment inside the opening container 1 with the electron beam. Can be performed satisfactorily. Since the upper surface of the irradiation protection plate 4 generates heat due to irradiation with the electron beam EB, a cooling means 9 such as a cooling pipe is installed when further measures against heat generation are required even if a material with good thermal conductivity is used. To suppress the temperature rise and endure long-term use.

  An electron beam deflector 41 that deflects the electron beam EB from the electron beam generating means 40 is disposed in the transfer path portion serving as the electron beam irradiation chamber of the irradiation processing tank 10. The electron beam deflector 41 is arranged at a position facing the electron beam generating means 40 and at a different position with respect to the height direction of the opening container 1. With this arrangement of the electron beam deflector 41, even when the electron beam EB is irradiated from above, the electron beam EB is deflected on the inner and outer surfaces of the opening container 1 and the entire surface in the height direction of the opening container 1 is irradiated well. Can do. The electron beam deflector 41 uses a permanent magnet, appropriately devise the electron beam EB, and devise the number and the arrangement position so that the entire surface of the open container 1 can be effectively irradiated.

  Furthermore, if the rotation carrier 11 is provided with a rotation mechanism for rotating the opening container 1, the opening container 1 can be rotated at the time of irradiation with the electron beam EB, and in addition to the use of the electron beam deflector 41 described above. The inner and outer surfaces can be irradiated more uniformly with the electron beam EB.

It is the schematic which shows the principle of the electron beam irradiation apparatus for open containers to which this invention is applied. It is a schematic longitudinal cross-sectional view which shows the principal part of the electron beam irradiation apparatus for open containers which is one Example of this invention. It is a schematic longitudinal cross-sectional view which shows the example of the irradiation protection board used for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Opening container, 2 ... Holding mechanism, 3 ... Partition, 4 ... Irradiation protection plate, 4A ... Flat plate part, 4B ... Hollow cylindrical part, 4C ... Small hole, 5 ... Desorption mechanism, 6 ... Guide guide, 7A ... Roller, 7B ... guide rail, 8 ... magnetic field deflecting means, 9 ... cooling means, 10 ... irradiation treatment tank, 11, 21, 31 ... rotating carrier, 13, 23, 33 ... vacuum exhaust device, 14, 24, 34 piping, 20 ... front pressure adjusting tank, 22, 32 ... small section, 30 ... rear pressure adjusting tank, 40 ... electron beam generating means. EB ... Electron beam.

Claims (3)

  An opening container having a neck portion is continuously conveyed by a rotating conveyance body, and the electron beam is irradiated in a reduced-pressure atmosphere during conveyance of the opening container during conveyance, and the irradiation protection plate of the irradiation conveying plate is rotated along with the rotational movement of the rotation conveyance body. A method for irradiating an electron beam of an opening container, comprising operating an attachment / detachment mechanism, mounting an irradiation protection plate near the neck of the opening container during electron beam irradiation, and removing the irradiation protection plate after electron beam irradiation.   A rotating transport body for continuously transporting the open container having a neck, an electron beam irradiation means for irradiating an electron beam in a reduced-pressure atmosphere during transport of the open container, and an irradiation protection plate disposed near the neck of the open container, An attachment / detachment mechanism for supporting the irradiation protection plate on the rotary transport body, and operating the rotary transport body along with the rotational movement of the rotation transport body to attach the irradiation protection plate during the electron beam irradiation and to remove it after the electron beam irradiation. An electron beam irradiation apparatus for an open container characterized by comprising: 3. The irradiation protection plate according to claim 2, wherein the irradiation protection plate is formed of a flat plate portion that does not transmit an electron beam and a cylindrical portion that is inserted into a neck portion of the opening container, and a magnetic field deflecting means for focusing the electron beam is provided on a lower surface of the flat plate portion. In addition, an electron beam irradiation apparatus for an open container characterized by comprising a cooling means.

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