JP5528247B2 - Electron beam irradiation device - Google Patents

Description

  The present invention relates to an electron beam irradiation apparatus that irradiates a resin container with an electron beam, and more particularly to an electron beam irradiation apparatus provided with a means for detecting the amount of electron beam irradiation.

  2. Description of the Related Art Conventionally, an apparatus that sterilizes a container by irradiating an electron beam from an electron beam irradiating means during conveyance of a plastic container such as a PET bottle is widely known. In such an apparatus that sterilizes by irradiation with an electron beam, if an irradiation failure occurs due to a decrease in the amount of irradiation of the electron beam for some reason, such as occurrence of sparks in the electron beam irradiation means, a resin Sterilization of the container made will be insufficient. When a container with insufficient sterilization is generated in this way, the container must be rejected outside the line before performing a process such as subsequent filling. Then, the electron beam sterilizer which can detect this when the irradiation amount of the electron beam with respect to a container is insufficient has already been proposed (for example, refer patent document 1 or patent document 2).

  The invention of an electron beam sterilization inspection system for food containers described in Patent Document 1 includes a food container transport device that transports food containers, and an electron beam irradiation device that irradiates the food containers transported by the food container transport device with an electron beam. And a physical property detection unit for detecting at least one physical property value changed by irradiating the food container with an electron beam by an electron beam irradiation device, and the physical property value (temperature, ozone concentration, charge amount) detected by the physical property detection unit , Color, etc.) or a physical property determination unit that determines whether or not the amount of change of the physical property value before and after electron beam irradiation is within a preset range.

  The invention described in Patent Document 2 measures the amount of electron beam irradiation by a current value. The electron beam irradiation apparatus described in Patent Document 2 is provided outside the irradiation window of the electron beam accelerator. A bar-shaped collector electrode along the short side of the irradiation window, a drive mechanism for moving the collector electrode in the electron beam irradiation region in the direction along the long side of the irradiation window, and a current flowing through the collector electrode And a current measuring unit. The collector electrode is electrically insulated from the ground by insulators provided at both ends thereof.

JP 2007-126171 A Japanese Patent Laid-Open No. 11-248893

  The invention described in Patent Document 1 examines whether or not the amount of the electron beam irradiated to the food container is appropriate, and measuring the amount of electrons transmitted through the material of the resin container Can not. The invention described in Patent Document 2 measures the dose distribution of an electron beam emitted from an electron beam irradiation apparatus, and cannot measure the amount of electrons transmitted through the material for each resin container. .

The present invention has been made in order to solve the above-described problems, and an electron beam that can be measured for each resin container by irradiating the resin container and penetrating the material into the inside. In an electron beam irradiation apparatus for irradiating a resin container with an electron beam from an electron beam irradiation means, an electron capturing member made of a conductive material that can be inserted from the mouth of the resin container; The current measuring means for measuring the current flowing through the electron capturing member is provided, and an electron beam is irradiated with the electron capturing member inserted into a resin container, and the current flowing through the electron capturing member is measured by the current measuring means. Thus, the amount of electrons reaching the inside of the resin container can be measured.

Further, the second invention includes a container transport unit provided with a plurality of support units for supporting the resin container, and an electron beam irradiation unit for irradiating the resin container with an electron beam. In an electron beam irradiation apparatus for irradiating a resin container with an electron beam from an electron beam irradiation means in a predetermined irradiation section, a conductive material provided corresponding to each of the support means and inserted into the inside from the mouth of the resin container. An electron capturing member comprising: elevating means for moving each electron capturing member up and down to enter and exit from the mouth of the resin container; and current measuring means for individually measuring the current flowing through each electron capturing member. In the irradiation section in the transport path of the transport means, the electron container is irradiated with an electron beam in a state where the electron capture member is inserted into a resin container supported and transported by the support means. Current flowing through By measuring, it is characterized in that it is possible to measure the amount of electrons reaching the interior of the individual resin vessel to be conveyed.

  In the electron beam irradiation apparatus of the present invention, the electron container is irradiated with an electron beam in a state where the electron capturing member is inserted into the resin container, and the current flowing through the electron capturing member is measured by the current measuring means. The amount of electrons reaching the inside of the resin container can be measured for each individual resin container.

FIG. 1 is a plan view schematically showing the entire configuration of the electron beam irradiation apparatus. Example 1 FIG. 2 is a longitudinal sectional view showing a main part of the electron beam irradiation apparatus. FIG. 3 is a graph showing an example of the measured current value.

  An electron beam irradiation apparatus that performs sterilization by irradiating an electron beam from the outside of a resin container with an electron beam irradiation means, and in particular, an electron capturing member that can be inserted into the inside of a resin container from the mouth, Current measuring means such as an ammeter for measuring the current flowing through the capturing member. When the electron container is irradiated with an electron beam from the electron beam irradiation means, if an electron capturing member is inserted into the resin container from the mouth, the electron beam irradiated to the resin container from the outside Since the current passes through the wall of the container and reaches the inside, is captured by the electron capturing member and flows to the ground side, this current is measured by a current measuring means provided between the electron capturing member and the ground. With this configuration, the object of measuring the electron beam irradiation amount for each individual resin container was achieved.

  Hereinafter, the present invention will be described with reference to embodiments shown in the drawings. A container 2 filled with contents such as a liquid in a subsequent process is irradiated with an electron beam by the electron beam irradiation apparatus according to this embodiment, and is a resin container such as a plastic bottle (see FIG. 2 described later). It is. The resin container 2 is supported on the lower surface side of the flange 2a formed on the neck portion by a support rail of an air conveyance conveyor (not shown), and air is blown from behind to be continuously conveyed to the electron beam irradiation device. . The transported resin container 2 is carried into the introduction chamber 4 and delivered to a carry-in wheel 6 disposed in the introduction chamber 4.

  The carry-in wheel 6 in the introduction chamber 4 is provided with a plurality of container holding means 8 at equal intervals in the circumferential direction, and receives and rotates and conveys the resin container 2 delivered from the upstream air conveyor. .

  Following the introduction chamber 4, when the resin container 2 is sterilized by irradiation with an electron beam, a shield chamber 10 composed of a lead wall that shields the electron beam and X-rays (braking X-rays) from leaking outside. Is installed. Inside the shield chamber 10, the supply chamber 14 on the inlet side where the supply wheel 12 is arranged and the resin container 2 received from the supply wheel 12 are transported, and an electron beam irradiation of an electron beam irradiation means 16 described later is performed. A main chamber 22 provided with a rotary-type container transport device 20 that moves in front of the window 18, and a discharge wheel that receives and discharges the resin container 2 sterilized by being irradiated with an electron beam from the electron beam irradiation means 16. 24 is partitioned into a discharge chamber 26 in which 24 is installed.

  An opening 10a through which the resin container 2 can pass is formed in a portion of the wall surface of the shield chamber 10 where the resin container 2 is transferred from the carry-in wheel 6 of the introduction chamber 4 to the supply wheel 12 in the supply chamber 14. ing. The supply wheel 12 that has received the resin container 2 from the carry-in wheel 6 of the introduction chamber 4 delivers the resin container 2 to the container transfer device 20 installed in the main chamber 22. An opening (not shown) through which the resin container 2 can be delivered is also formed in the partition wall 14 a between the supply chamber 14 and the main chamber 22. In the container transfer device 20 installed in the main chamber 22, a number of grippers 28 (see FIG. 2 described later) are provided as container holding means on the outer peripheral portion of the rotating body 30 at equal intervals in the circumferential direction. Also, a plurality of supply wheels 12 that receive the resin container 2 from the container holding means 8 of the carry-in wheel 6 disposed in the introduction chamber 4 and deliver it to the gripper 28 of the container transfer device 20 are arranged at equal intervals in the circumferential direction. The container holding means 32 is provided.

  An electron beam irradiation means 16 is arranged adjacent to one side wall (upper side wall in FIG. 1) of the lead shield chamber 10. As is well known, the electron beam irradiation means 16 heats the filament in a vacuum in a vacuum chamber to generate thermoelectrons, accelerates the electrons with a high voltage to form a high-speed electron beam, The article to be irradiated (resin in this embodiment) is taken out into the atmosphere through a metal window foil made of Ti or the like attached to the irradiation window 18 provided on the irradiation window 18 and positioned in the electron beam irradiation area A in front of the irradiation window 18. Processing such as sterilization is performed by applying an electron beam to the container 2).

  As described above, the front side of the irradiation window 18 of the electron beam irradiation means 16 is an electron beam irradiation area A that defines an irradiation section in which the resin container 2 is irradiated with an electron beam. A discharge chamber 26 surrounded by a wall surface 26a and a top surface 26b is formed from the vicinity of the position where the resin container 2 transported by the container transport device 20 passes through the electron beam irradiation area A. The resin container 2 that has been irradiated with the electron beam in the electron beam irradiation area A that defines the irradiation section is delivered from the gripper 28 of the container transfer device 20 to the discharge wheel 24 installed in the discharge chamber 26. The discharge wheel 24 is provided with a plurality of container holding means 34 at equal intervals in the circumferential direction, and the resin container 2 held by the gripper 28 of the container transfer device 20 is taken out by the container holding means 34. Discharged.

  The discharge wheel 24 in the discharge chamber 26 also serves as a reject wheel. When it is determined that the resin container 2 is properly sterilized as described later, the discharge wheel 24 is received from the container transport means 20. The resin container 2 is delivered to the container holding means 38 of the carry-out wheel 36 installed in the next intermediate chamber 35 and sent to a downstream process such as a filler and a capper (not shown). An opening 10b through which the resin container 2 can pass is formed in a portion of the wall surface of the shield chamber 10 where the resin container 2 is transferred from the discharge wheel 24 of the discharge chamber 26 to the carry-out wheel 36 in the intermediate chamber 35. ing. On the other hand, when it is determined that the sterilization of the resin container 2 is incomplete due to an insufficient amount of electron beam irradiation, the shield chamber 10 is not transferred to the carry-out wheel 36 of the intermediate chamber 35. It discharges to the rejection part 39 arrange | positioned adjacently. The position indicated by the symbol B in FIG. 1 is the reject position. An opening 10c through which the resin container 2 can pass is also formed at a position B on the wall surface of the shield chamber 10 where the resin container 2 is discharged from the discharge wheel 24 of the discharge chamber 26 to the reject portion 39.

  The container transport device 20 is provided with an encoder 40, and a pulse signal of the encoder 40 is sent to the control device 42, and the rotational position of the rotating body 30 of the container transport device 20, that is, the resin held by each gripper 28. The position of the container 2 is always detected. Further, the discharge wheel 24 installed on the downstream side of the container transport device 20 is also provided with an encoder 44, and its pulse signal is input to the control device 42, and is delivered from the gripper 28 of the container transport device 20. Thus, the position of the resin container 2 held by the container holding means 34 can always be detected. Therefore, as will be described later, when the irradiation amount of the electron beam irradiated from the electron beam irradiation means 16 is insufficient or excessive, this irradiation failure is caused by a signal from the encoder 40 of the container transport device 20. The resin container 2 can be specified, and the resin container 2 can be traced by the pulse signal of the encoder 44 of the reject wheel (discharge wheel) 24 and extracted from the reject wheel 24.

  As shown in FIG. 2, the container transporting device 20 has grippers 28 provided at equal intervals in the circumferential direction on the outer peripheral portion of the rotating body 30, and in the resin container 2 corresponding to these grippers 28. Electron capturing members (earth rods) 60 made of an insertable electrical conductor are respectively disposed. A horizontal support member 64 facing the radially outer side is fixed on the outer peripheral portion of the rotating body 30 via an upright support column 62, and an actuator such as a linear slider or an air cylinder stands upright on the support member 64. The lifting / lowering means 66 is fixed. The earth rod 60 is supported by the elevating means 66 so as to be elevable. A horizontal support member 68 is connected to a drive part of the elevating means 66, for example, a piston rod of an air cylinder, and a holding member 70 is fixed to the tip of the support member 68 so as to face the vertical direction. It is held in an insulated state at the lower end of the holding member 70. When the earth rod 60 is raised by driving the elevating means 66, the lower end portion of the earth rod 60 comes out above the mouth portion 2b of the resin container 2, and when the earth rod 60 is lowered, the lower end portion 60a of the earth rod 60 is made of the resin container. Until the bottom surface 2c of 2 is reached. In addition, as a material of the electron capture member (earth rod) 60, metals such as stainless steel, aluminum, and titanium, and other conductive materials can be used. In addition to the round bar shape, the cross section may be rectangular, rectangular or polygonal, and it may be formed in a saw blade shape such as a large number of protrusions on the outer peripheral surface or a brush to induce charge. May be configured to be easier

  A fixed contact 72 is provided on the upper surface of the distal end portion of the support member 64 that supports the elevating means 66, while the horizontal attachment member 68 to which the earth rod 60 is attached corresponds to the fixed contact 72 vertically. A movable contact 74 is provided at a position, and when the earth rod 60 is lowered, the movable contact 74 is lowered to contact the fixed contact 72 and these contacts are conducted. Inside the holding member 70 holding the earth rod 60, the horizontal mounting member 68, the support member 64, the support column 62, the rotating body 30, and the like, a covered insulated wire 75 is disposed. The earth rod 60 and the current measuring means (ammeter) 76 are connected to each other. When the electron beam irradiated from the outside of the resin container 2 passes through the wall surface of the resin container 2 and is captured by the earth rod 60 inserted inside, the inside of the holding member 70 and the horizontal mounting member 68 A current flows to the ground side through the insulated wire 75, the contact (the fixed contact 72 and the movable contact 74), the support member 64, the support 62, and the insulated wire 75 in the rotating body 30. An ammeter 76 is used for measurement. The current value measured by the ammeter 76 is input to the control device 42.

  The current value sent from the ammeter 76 to the control device 42 is compared with a predetermined reference value in the comparison means 54. Based on the comparison result by the comparison means 54, the irradiation amount of the electron beam irradiated from the electron beam irradiation means 16, penetrates the material of the resin container 2, penetrates the wall surface and reaches the inside, that is, the amount of electrons is appropriate. The determination means 56 determines whether or not there is. When the determination by the determination means 56 is inappropriate, the resin container 2 having an inappropriate amount of electron beam transmitted through the reject wheel (discharge wheel 24) is extracted and rejected by a command from the command means 58. The electron beam irradiating means 16 is provided with a current monitor 78 as a supply current recognizing means to constantly monitor the output value of the current, and the comparing means 54 recognizes the electron beam irradiation recognized by the current monitor 78. The reference value is changed according to the fluctuation of the supply current value to the means 16. Thus, in the present invention, the amount of electrons that have reached the inside of the resin container 2 can be measured by measuring the value of the current flowing through the earth rod 60 with the ammeter 76.

  The operation of the electron beam irradiation apparatus according to the above configuration will be described. The resin container 2 conveyed by an air conveyance conveyor (not shown) enters the introduction chamber 4 and is delivered to the container holding means 8 of the carry-in wheel 6. After being rotated and conveyed by the carry-in wheel 6, the resin container 2 is delivered to the supply wheel 12 installed in the supply chamber 14 of the lead shield chamber 10 and is held by the container holding means 32 of the supply wheel 12. It is rotated and transferred to the gripper 28 of the container transfer device 20 in the main chamber 22.

  The resin container 2 held by the gripper 28 of the container transport device 20 and rotated and transported as the rotating body 30 rotates is placed in the electron beam irradiation zone A located on the front side of the irradiation window 18 of the electron beam irradiation means 16. To reach. In this electron beam irradiation zone A, an electron beam is irradiated from the irradiation window 18 of the electron beam irradiation means 16, and the resin containers 2 held respectively by grippers 28 provided at predetermined intervals on the container transport device 20. Is irradiated with an electron beam. A part of the electron beam irradiated from the outer surface side of the resin container 2 passes through the wall surface of the resin container 2 and enters the inner side, and the inner surface of the resin container 2 is sterilized. In this embodiment, when each resin container 2 reaches the electron beam irradiation zone A, the earth rod 60 is lowered by the elevating means 66 so that the electron beam is emitted while the earth rod 60 is inserted into each resin container 2. Since the light is irradiated, the electrons that have passed through the wall surface of the resin container 2 and have reached the inside are captured by the ground rod 60, and then the insulated wires 75 and contacts (fixed) in the holding member 70 and the horizontal mounting member 68. It flows to the ground side through the contact 72 and the movable contact 74), the support member 64, the support 62, and the insulated wire 75 in the rotating body 30. This current is measured by an ammeter 76. Thereafter, when the resin container 2 passes through the electron beam irradiation zone A, the earth rod 60 is raised by the elevating means 66 and extracted from the resin container 2.

  The current value E1 (see FIG. 3) measured by the ammeter 76 is sent to the control device 42 and compared with the reference value by the comparison means 54. The determination by comparison with the reference value of the measured current value E1 is determined to be excessive when the peak of the maximum value exceeds the upper limit reference value S1, and insufficient when the peak is lower than the lower limit reference value S2. When the current value indicated by the solid line E1 in FIG. 3 is measured, the peak of the maximum value falls between the upper limit reference value S1 and the lower limit reference value S2, and it is determined that the electron beam irradiation amount is appropriate. . The resin container 2 determined to have an appropriate electron beam irradiation amount is transferred from the gripper 28 of the container transport device 20 to the container holding means 34 of the discharge wheel 24 and further installed in the next intermediate chamber 35. It is delivered to the container holding means 38 of the carry-out wheel 36 and sent to the next process such as a filler and a capper. Note that the current value E1 shown in FIG. 3 temporarily decreases at the peak because the irradiation window 18 of the electron beam irradiation means 16 is divided into two, and the electron beam irradiation is temporarily interrupted between the two.

  On the other hand, when the peak of the maximum value of the measured current value E1 is below the lower limit reference value S2, there is a risk that complete sterilization will not be performed because the amount of electron beam irradiation to the resin container 2 is insufficient. Therefore, the determination unit 56 determines that the container is defective. When the peak of the measured current value E1 exceeds the upper limit reference value S1, the electron dose applied to the resin container 2 is excessive, and the resin container 2 is deformed or discolored. The determination means 56 determines that the container is defective. In addition, when the irradiation amount of the electron beam irradiated from the electron beam irradiation means 16 is constant, when the conveyance speed of the resin container 2 is low, the irradiation is excessive, and when the conveyance speed is high, the irradiation is excessive. The appropriate dose is changed according to the transport speed. Therefore, the amount of irradiation commanded to the electron beam irradiation means 16 is recognized by measuring the current value supplied to the electron beam irradiation means 16 by the supply current recognition means (current monitor) 78, and the reference value is determined accordingly. To change.

  The resin container 2 determined as a defective container by the determination means 56 of the control device 42 is specified by the number of pulses of the encoder 40 provided on the rotating body 30 of the container transport device 20. Thereafter, the resin container 2 is delivered from the gripper 28 of the container transport device 20 to the container holding means 34 of the discharge wheel 24. The discharge wheel 24 is also provided with an encoder 44, and the resin container 2 determined to be a defective container in the container transport device 20 is tracked after being delivered to the discharge wheel 24 and removed at the reject position B. And discharged to the reject unit 39. In this embodiment, not only the resin container 2 itself determined that the measured current value E1 deviates from the reference values S1 and S2, but also the resin containers 2 before and after that are extracted. .

  In the apparatus according to this embodiment, the electron beam is irradiated with each electron-contained member (earth rod) 60 inserted into each resin container 2, so that each resin container 2 is transmitted through the wall surface. Thus, the amount of electrons of the electron beam reaching the inside can be measured. By rejecting those below the reference value using this individual irradiation amount, the state of sterilization in units of one resin container can be confirmed. In the above-described embodiment, the ammeter 76 is provided for each earth rod 60. However, it is not always necessary to provide the ammeters individually, and one or a plurality of ammeters 76 are provided to reach the electron beam irradiation zone A. It is also possible to configure such that each rod 60 is switched and connected by a relay, and current values are individually measured.

2 Resin container 16 Electron beam irradiation means 60 Electron capture member (earth rod)
76 Current measuring means (ammeter)

Claims (2)

In an electron beam irradiation apparatus that irradiates a resin container with an electron beam from electron beam irradiation means,
An electron capturing member made of a conductive material that can be inserted into the inside of the resin container from the mouth, and a current measuring means for measuring the current flowing through the electron capturing member,
Measure the amount of electrons that have reached the inside of the resin container by irradiating an electron beam with the electron capture member inserted into the resin container and measuring the current flowing through the electron capture member with the current measuring means. An electron beam irradiation apparatus characterized in that A container transport means provided with a plurality of support means for supporting the resin container; and an electron beam irradiation means for irradiating the resin container with an electron beam, and the resin container in a predetermined irradiation section in the transport path of the container transport means In the electron beam irradiation apparatus for irradiating the electron beam from the electron beam irradiation means,
An electron capturing member made of a conductive material provided corresponding to each of the support means and insertable into the inside of the resin container from the mouth, and each electron capturing member is moved up and down to enter and exit from the mouth of the resin container. Elevating means, and current measuring means for individually measuring the current flowing through each electron capturing member,
In the irradiation section in the transport path of the container transporting means, a resin container supported by the supporting means and transported is irradiated with an electron beam while the electron capturing member is inserted, and each electron is measured by the current measuring means. An electron beam irradiation apparatus characterized by being able to measure the amount of electrons that have reached the inside of each resin container to be conveyed by individually measuring the current flowing through the capturing member.

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