JPS6050648B2 - Electron beam sterilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam sterilizer that sterilizes packaging materials that are intermittently conveyed by irradiating them with electron beams.

Generally, when packaging materials are sterilized, H is used as a chemical method.

O. Immersion sterilization and EOG (ethylene oxide gas)
Sterilization, etc. However, O2 sterilization has been practiced for a long time and has become a common sterilization method. This method allows for in-line sterilization inside the packaging machine, as well as heat H. O.
Although it is possible to perform reliable sterilization including cleaning effects, H2O2 may remain in the product due to wet sterilization. Although this residual amount is so small that it cannot be detected, some consumers may be concerned about H. I have a psychological allergy to 02, which makes it difficult for me to use it.

Furthermore, since EOG is gaseous, batch sterilization is required, making in-line sterilization impossible and EOG remaining in products, making it difficult to use.
Furthermore, physical sterilization methods include gamma ray sterilization and ultraviolet sterilization.

Furthermore, since gamma ray sterilization can penetrate plastic packaging materials, it is an effective sterilization method that can perform sterilization in the final step, similar to gas sterilization. However, this method has drawbacks such as a decrease in heat sealing strength after irradiation with gamma rays and deterioration of physical properties such as odor. Also,
Cobalt-60 is often used as a radiation source, and it has social disadvantages such as difficulty in handling, limited use period (half-life of 5 years), need for shielding plates, and radiation allergy unique to Japanese people. There it is. On the other hand, ultraviolet sterilization has the advantage that it has less effect on the human body and is easier to handle than other radiation rays, and because it is a dry sterilization, there is no residual chemical agent or the like, so there are fewer problems. However, in the past, UV lamps were not used alone due to their weak sterilizing power and were used as an auxiliary means, but in recent years, ultraviolet lamps with strong sterilizing power have been developed, and there is no problem in practical use. It has become more and more powerful. However, although it is a sumo wrestler, it has the disadvantage that ultraviolet rays only act on the surface of the packaging material, and if there is dust etc. on that part, it cannot be sterilized in that area, and it is said that complete sterilization cannot be achieved. As described above, the reality is that there is no perfect and safe sterilization method at present.

Here, in contrast to the above-mentioned sterilization method, an electron beam is artificially created and the energy is increased to achieve material penetration of the electron beam, thereby sterilizing not only the surface but also the back and inner surfaces of the packaging material. This method has emerged as a powerful method in recent years. However, during electron beam irradiation, X
Because lines are generated, it is necessary to adopt a shielding structure or form a maze, which poses problems in transporting packaging materials. In general, sheet-shaped packaging materials can be formed into a labyrinth structure relatively easily and are easy to transport.

However, there is a need for connection with a filling and packaging machine, etc., and continuous conveyance is not possible, but intermittent conveyance has become necessary. For this reason, uniform irradiation was not achieved, which usually resulted in deterioration of the packaging material. In other words, if the packaging material is transported continuously, there will be little variation in the absorbed dose and uniform sterilization is possible, but if the packaging material is transported intermittently, the packaging material will receive an excessive amount of absorbed radiation due to irradiation while it is stopped, which may cause deterioration of the packaging material. , there is a risk of losing its performance as a packaging material. This invention was made in view of the above-mentioned circumstances, and is designed to uniformly sterilize packaging materials that are intermittently conveyed with electron beams.

This invention will be explained below.

1 and 2 are diagrams showing an embodiment of the present invention, in which a packaging material 1 is intermittently conveyed along an uneven path forming a labyrinth along a large number of conveyance rollers 2. Lead shielding plates 3 and 4 are arranged along the route.

An electron beam irradiation device 7 having an electron beam heater 5 and a scanning electromagnetic deflection section 6 is provided in the recessed portion of the shielding plate 3. At the same time, the electron beam 8 from the electron beam irradiation device 7 is cut by a lead plate 9 disposed on the opposite side of the shielding plate 4. Further, between the packaging material 1 and the electron beam irradiation device 7, a pair of drive rollers 12 around which an irradiation belt 11 is wound,
A shutter mechanism 110 consisting of 12 is provided, and the drive rollers 12, 12 are driven in a single pulse in response to the conveyance of the packaging material 1. The irradiation belt 11 has a closed portion 11A as shown in FIG. 3, and short openings 11B are provided at regular intervals.
1A is a structure that cuts transmission of the electron beam 8, for example 0.
It is made of stainless steel plate that can be used for 1 min to 0.5 min.
Further, the upper and lower portions of the irradiation belt 11 are in a positional relationship such that the openings 11B exactly overlap each other, as shown in FIG. Further, a slit nozzle 20 for supplying sterile air is arranged near the electron beam irradiation section of the shutter mechanism 10. The operation of such a configuration will be explained with reference to the time charts of FIGS. 4A to 4E and the state diagrams of FIGS. 5A to 5H. Note that ST in FIG. 5 indicates the sterilization state of the packaging material 1. The packaging material 1 is intermittently conveyed via the conveyance roller 2, and the conveyance timing is as shown in FIG. A clock as shown in Figure B is generated, and the shutter mechanism 10 is thereby driven in a single pulse (C in the same figure).
.

However, packaging material 1 has stopped. At the time shown in FIG. 4, the state of the irradiation belt 11 of the shutter mechanism 10 is as shown in FIG. 5A, and the state at time T2, just before the shutter mechanism 10 is driven by the clock and the shutter is opened, is the same. It will look like Figure B. Immediately after the shutter mechanism 10 is driven in a single pulse manner for a predetermined time as shown in FIG. 4C, and the shutter is opened as shown in FIG. 4D, the state as shown in FIG. 5C is obtained. The packaging material 1 also undergoes a conveying operation, whereby the packaging material 1 is sterilized by the electron beam 8 (FIG. 4E). and,
This sterilization state continues at times T4, t5, and t6, and the state also becomes as shown in FIG. 5 D, E, and F, and the packaging material 1 is effectively sterilized. Such sterilization continues, and just before the conveyance of the packaging material 1 is stopped, the shutter mechanism 10 is driven by the clock in a single pulse for a predetermined period of time (FIGS. 4B and 4C). 5
The shutter closes as shown in Figure G, and at time T8, the shutter closes as shown in Figure H, and the sterilization operation ends. Similarly, the shutter mechanism 10 is driven in a single pulse in conjunction with the conveyance and stopping of the packaging material 1, thereby performing uniform sterilization. Note that sterile air is blown from the slit nozzle 20 onto the packaging material just before being sterilized with electron beams to prevent contamination of the shutter mechanism 10.
Further, the lead plate 9 promotes the backscattering effect of the electron beam 8.
As described above, according to the sterilizer of the present invention, packaging materials that are intermittently conveyed can be effectively and uniformly sterilized with electron beams.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a schematic perspective view thereof, FIG. 3 is a diagram showing an example of a belt of a shutter mechanism used in this invention, and FIG. 5A to 5H are diagrams showing the relationship between the shutter mechanism and the packaging material at the timing. 1... Packaging material, 2... Conveyance roller,
3, 4... Shielding plate, 5... Electron beam heater, 6... Electromagnetic deflection unit for scanning, 7...
Electron beam irradiation device, 8...Electron beam, 9...
・Lead plate, 10...Shutter mechanism, 11...
Irradiation belt, 12... Drive roller, 20...
...Slit nozzle.

Claims (1)

[Scope of Claims] 1. In an apparatus for sterilizing packaging materials that are intermittently conveyed by irradiating them with electron beams, a shutter mechanism is disposed between the electron beam irradiation section and the packaging materials, and An electron beam sterilizer characterized in that the shutter mechanism is opened and closed in accordance with the timing of transporting and stopping packaging materials. 2. The electron beam sterilizer according to claim 1, wherein the shutter mechanism is constituted by an irradiation belt having a structure in which open and closed portions are arranged alternately. 3. The electron beam sterilizer according to claim 1 or 2, further comprising a slit nozzle for supplying sterile air to the packaging material before it passes through the electron beam sterilization section.