JPH0719039Y2 - Short-circuit device for electron beam irradiation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an accelerating electrode short-circuit device used in an electron beam irradiation device.

(Prior Art) As is well known, in an accelerating tube of an electron beam irradiation device, a shield ring for relaxing an electric field is provided around the accelerating tube in correspondence with each stage of accelerating electrodes, and the same as the corresponding accelerating electrodes. It is electrically connected so as to have a potential.

By the way, in this type of apparatus, when operating at a voltage lower than the maximum voltage, the number of stages of the accelerating electrodes may be reduced and used. Therefore, conventionally, a short-circuit rod which is grounded is prepared, and the shield ring is short-circuited by rotating the short-circuit rod.

FIG. 2 shows the conventional structure, 1 is an accelerating tube, 2 is a shield ring, 3 is a short-circuit device, a short-circuit rod 4, a motor 5 for turning the same in a horizontal plane, and the motor 5 is installed at a required height. It is composed of a tower 6 and the like. Reference numeral 7 is a shield cover for covering the short-circuit device 3, and 8 is a pressure tank for housing the electron beam irradiation device.

According to this configuration, if the short-circuit rod 4 is swung by the motor 5, the shield ring 2 located at the same height as the short-circuit rod 4 comes into contact with the shield ring 2 as shown in the figure, and the shield ring 2 can be short-circuited. Like

(Problems to be solved by the invention) By the way, in such a configuration, for high voltage (for example,
In the electron beam irradiation device of 750 kV or more), the shield cover 7 can be installed in the pressure tank 8 even if the pressure tank 8 becomes large, but for low voltage (for example, 550 kV or less).
In this case, the pressure tank also becomes small, so that the space for installing the short-circuit device 3 may be lost.

Explaining this in detail, as shown in the figure, the shield cover 7
When the is installed in the pressure tank 8, it is necessary to secure a required insulation distance L between this and the shield ring 2.

However, if the pressure tank 8 becomes smaller as described above, the insulation distance L cannot be secured accordingly, and if the distance becomes shorter than this, discharge will occur between the two.

It is an object of the present invention to ensure a necessary insulation distance between the shield ring and the shield cover that covers the short-circuit device even if the pressure tank is downsized.

(Means for Solving the Problem) In this invention, a place located below a shield ring to be short-circuited is set as a rotation center of a short-circuiting rod of a short-circuiting device, and this is rotatably installed in a vertical plane. The short circuit device is covered by a shield cover.

(Operation) The short-circuit rod is installed below the shield ring which is going to be short-circuited, and is rotated in the vertical plane. By this rotation, the short-circuit bar comes into contact with the shield ring and short-circuits.

Since the short-circuit bar rotates about its lower part, its tip in the unused state can be rotated to a position sufficiently separated from the shield ring. Therefore, the shield cover that covers this can also be installed at a position sufficiently separated from the shield ring.

Therefore, even if the shield ring and the side wall of the pressure tank are narrow, a sufficient insulation distance can be secured between them.

(Embodiment) An embodiment of the present invention will be described with reference to FIG. The second
Portions with the same reference numerals as those in the figure indicate the same or corresponding portions. According to this invention, the motor 5 is installed below the acceleration tube 1, for example, near the shield ring 2 in the second stage from the bottom or a position lower than the shield ring 2.

As a result, the center of rotation of the short-circuit rod 4 is located at a position lower than that of the shield ring 2 which is about to be short-circuited. The miniaturization of the pressure tank 8 brings the motor 5, the tower 6, and hence the shield cover covering this portion closer to the shield ring, but this is not a problem because the potential of the lower shield ring is low.

The short-circuit rod 4 is rotated in the vertical plane by the motor 5.
This rotation makes contact with the shield ring 2 and short-circuits the shield ring 2. When the short-circuit device 3 is not used, the short-circuit device 3 is rotated to a position approaching the side wall of the pressure tank 8 as shown by the dotted line in the figure. At this position, it is covered by the shield cover 7.

In this case, as can be understood from the position in the drawing, the short-circuit bar 4 is close to the side wall of the pressure tank 8 and is sufficiently separated from the shield ring 2. Therefore, the shield cover 7 that covers it can also be installed at a position sufficiently separated from the shield ring 2. As a result, the insulation distance L can be sufficiently secured.

(Effect of the Invention) As described in detail above, according to the present invention, the center of rotation of the short-circuit rod of the short-circuit device is simply installed below the accelerating tube and is rotated in the vertical plane. Even if the pressure tank is downsized, the insulation distance between the shield cover and the shield ring that covers the short-circuit device can be sufficiently secured.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a front view showing a conventional example. 1 ... Accelerator tube, 2 ... Shield ring, 3 ... Short-circuit device, 4 ...
Shorting rod, 5 ... motor, 7 ... shield cover, 8 ... pressure tank,

Claims (1)

[Scope of utility model registration request] 1. A pressure tank is provided with an accelerating tube, a shield ring provided around the accelerating tube, and a short-circuiting device provided with a short-circuiting rod that comes into contact with the shield ring to short-circuit the shield ring. In a short-circuit device for an electron beam irradiation device, the short-circuit rod is rotatably installed in a vertical plane with a position located below a shield ring to be short-circuited by the short-circuit rod as a rotation center, and the short-circuit device is also provided. A short-circuit device for electron beam irradiation devices, which is covered with a shield cover.