JPH02181700A - Electron beam projector - Google Patents

Abstract

PURPOSE:To prevent the leakage of ozone without enlarging and complicating the entire part of the device by building adsorbents which adsorb the ozone generated in an electron beam projection space by the electron beam transmitted through a thin metallic film into the electron beam projection space. CONSTITUTION:An object 7 to be irradiated moves form the left to the right in the electron beam projection space 18 and the generated ozone moves together with the object 7 and is liable to leak to the outside from a drawing out port on the right side; therefore, the adsorbents 9 are arrayed continuously to the right side from the thin metallic film 11 up to the drawing out port on the front surface side of the object to be irradiated. The concn. of the ozone in the electron beam projection space is lowered inexpensively without enlarging and complicating the entire part of the device in this way and the leakage of the ozone in the electron beam projection space is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is used for sterilization of electric cable cable insulating coatings, beverage containers, etc., and is a vacuum container having a window frame closed by a single thin metal film. An object to be irradiated in an electron beam irradiation space defined outside the metal thin film with the metal thin film as part of the wall surface, by generating electrons within the space and accelerating the electrons with an electric field to transmit the metal thin film. The present invention relates to an electron beam irradiation device for irradiating.

[Conventional technology]

FIG. 3 shows an example of a conventional configuration of this type of electron beam irradiation device.

In a vacuum vessel 1 at ground potential and having a window frame 1a closed by a thin metal m11, a cathode 2 electrode surface to which a negative high voltage is applied from a power source on the atmosphere side (not shown) is directed toward the window frame la. On the other hand, a negatively charged grid 3 is arranged on the cathode 2 side of the window frame 1a, and a plasma raw material gas is introduced into the space between the grid 3 and the metal thin film 11. Plasma 4 is formed by applying a voltage from the atmosphere to a wire electrode (not shown) placed in the space. Ions in the plasma are drawn into the vacuum chamber 1 by the grid 3, accelerated by the cathode 2, collide with the cathode 2, and cause the cathode 2 to emit secondary electrons. The emitted secondary electrons are accelerated toward the window frame 1a by the negative potential of the cathode 2, pass through the grid 3, pass through the plasma 4, pass through the metal thin film 11, cross the atmosphere, and pass through the metal thin film 11. An irradiated object 7 moving in an electron beam irradiation space 8 having a part of the wall surface is irradiated, and a bridge 1
Perform treatments such as polymerization and sterilization. The metal thin film 11 has a thickness that maintains the vacuum of one circle of the vacuum container, and has a function of transmitting electrons. For example, pure aluminum foil is used. An exhaust duct 12 is provided in the electron beam irradiation space 8, and by exhausting air containing ozone in the electron beam irradiation space 8, the concentration of ozone generated in the electron beam irradiation space 8 during electron beam irradiation is kept low. , the effect of ozone inhibiting electron beam processing, and the effect of corroding the rotating parts of the drive unit 9 of the object to be irradiated (not shown) are suppressed. Further, since ozone generated in the electron beam irradiation space 8 oxidizes the surface of the metal thin film 11 and shortens its life, as shown in FIG. Countermeasures have been proposed, such as forming an acid-resistant film 2 on the surface of the space 8, such as a film of titanium or titanium nitride (see Japanese Patent Laid-Open No. 178700/1983).
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[The problem that the invention attempts to solve]

Even in an electron beam irradiation device configured in this way to suppress the harm caused by ozone, the following points can still be considered as problems. That is, in a device that exhausts ozone using an exhaust duct, the entire device becomes large and complicated. In addition, forming an acid-resistant film on a thin metal surface increases the cost of film formation because it is necessary to uniformly deposit the acid-resistant film on a large area (for example, several + α angle) of the thin metal film surface. Even if the oxidation of the metal thin film is prevented by the formation of a chemical film alone, the generated ozone, which is harmful to the human body, will pass from the electron beam irradiation space to the outside through the gap between the insertion or extraction port of the irradiated object. Due to leakage, there is a problem in that people cannot get close to the device during irradiation. Therefore, if an exhaust system including an exhaust duct is used in combination with a metal thin film coated with an acid-resistant film, the harm caused by ozone can be significantly reduced, but the system becomes large and expensive.

In view of the problems of the conventional device as described above, the purpose of this invention is to suppress the ozone concentration in the electron beam irradiation space at low cost without increasing the size of the device, and to prevent ozone leakage to the outside of the electron beam irradiation space. An object of the present invention is to provide an electron beam irradiation device that can substantially prevent the above.

[Means to solve the problem]

In order to solve the above problems, in the present invention, electrons are generated in a vacuum container having a window frame closed by a metal thin film, and the electrons are accelerated by an electric field to pass through the metal thin film. In an electron beam irradiation device that irradiates an object in an electron beam irradiation space defined with the metal thin film as part of the wall surface on the outside of the An adsorbent that adsorbs ozone generated in the space is built into the electron beam irradiation space.

[Effect]

Activated carbon, which is found in refrigerator deodorizers and cigarette filters, is a familiar adsorbent that is built into the electron beam irradiation space. Activated carbon has a strong gas adsorption effect and is porous, so it has a large adsorption surface area (and can adsorb a large amount of gas).

Therefore, by incorporating such an adsorbent in an appropriate amount and position in the electron beam irradiation space in accordance with the electron beam dose, the ozone concentration in the electron beam irradiation space can be kept low and the ozone to the outside can be prevented. Leakage can also be substantially prevented, as mentioned above.

Suppression of ozone damage in the electron beam irradiation space.

It becomes possible for people to approach the device during electron beam irradiation at low cost.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In the figure, the same members as in FIG. 3 are designated by the same reference numerals, and their explanations will be omitted. Inside the electron beam irradiation space 18, the irradiated object 7 moves from left to right, and the generated ozone moves with the irradiated object 7 and easily leaks to the outside from the right drawer opening. The agent 9 is continuously arranged on the right side of the metal thin film 11 and on the upper surface of the object to be irradiated up to the outlet. In addition to the configuration of this embodiment, if adapters are provided at the insertion and extraction ports of the irradiated object in the electron beam irradiation space to further reduce the gap between the irradiated object and the irradiated object, ozone leakage can be prevented. You can get even more reliable effects with this method.

〔Effect of the invention〕

As described above, according to the present invention, electrons are generated in a vacuum container having a window frame closed by a metal thin film, and the electrons are accelerated by an electric field to pass through the metal thin film. In an electron beam irradiation device that irradiates an object to be irradiated in an electron beam irradiation space defined as a part of the wall surface with the metal thin film on the outside of the metal thin film, an electron beam transmitted through the metal thin film is used to irradiate the object in the electron beam irradiation space. Since an adsorbent that adsorbs the generated ozone is built into the electron beam irradiation space, the ozone concentration in the electron beam irradiation space can be reduced and the electron beam Ozone leakage to the outside of the irradiation space can be prevented, the life of the metal thin film can be extended without the need for expensive acid-resistant migration formation on large-area metal thin films through which electron beams can pass, and at the same time There is no danger to the human body outside, and it becomes possible to approach the equipment even during electron beam irradiation.

[Brief explanation of the drawing]

FIG. 1 is an overall sectional view of an electron beam irradiation device showing an embodiment of the present invention, FIG. 2 is a sectional view showing an example of a conventional means for preventing oxidation of a metal thin film, and FIG. FIG. 2 is an overall sectional view showing a configuration example. DESCRIPTION OF SYMBOLS 1... Vacuum container, 1a... Window frame, 2... Cathode, 6... Electron beam, 7... Irradiated object, 8, 18...
Electron beam irradiation space, 9...adsorbent, 10...ozone,
11.21...Metal thin film.

Claims (1)

[Claims] 1) Electrons are generated in a vacuum container having a window frame closed by a metal thin film, and the electrons are accelerated by an electric field to pass through the metal thin film, and the metal thin film is placed on a part of the wall surface outside the metal thin film. In an electron beam irradiation device that irradiates an object to be irradiated in an electron beam irradiation space defined as An electron beam irradiation device characterized by being built into an irradiation space.