JPH0583836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for constructing a sintering furnace used for sintering pellets of nuclear fuel assemblies.

"Prior Art" Conventionally, a sintering furnace shown in FIG. 5 has been provided as an example of the above-mentioned sintering furnace.

In this figure, reference numeral 1 indicates the sintering furnace main body. This sintering furnace main body 1 has a U-shaped cross section and is constructed by stacking a large number of rectangular parallelepiped refractory bricks 2 vertically and horizontally. Therefore, inclined surfaces 3, 3 are formed which gradually approach each other. Square-shaped refractory bricks 4, 4 are closely attached to these inclined surfaces 3, 3, and the mutually opposing side surfaces of these refractory bricks 4, 4 form inclined surfaces 5, 5 that gradually approach each other as they go downward. It's summery. A trapezoidal refractory brick 6 is placed between these inclined surfaces 5, 5 with both sides thereof brought into close contact with the inclined surfaces 5, 5. Incidentally, heaters 7, 7 are provided on both sides of the sintering furnace main body 1.

"Problems to be Solved by the Invention" By the way, in the above-mentioned sintering furnace, when the inside of the sintering furnace main body 1 is heated by the heaters 7, 7, the refractory bricks 6
The lower part of the is hotter than the upper part. This fire brick 6
has heat shrinkability, and due to the difference in heat shrinkage due to the temperature gradient, a crack 8 extending horizontally is generated in the part indicated by the symbol A of the refractory brick 6, and the part located below this crack 8 is sintered. Furnace body 1
There were times when I fell inside.

``Object of the invention'' This invention was made in view of the above problems, and aims to prevent cracks from occurring in firebricks,
The object of the present invention is to provide a method for constructing a sintering furnace in which the refractory bricks do not fall into the sintering furnace body.

"Means for Solving the Problems" The method for constructing a sintering furnace of the present invention includes forming inclined surfaces on the upper inner surface of the concave sintering furnace body, which face each other and gradually approach each other toward the bottom. form,
In a method for constructing a sintering furnace, a heat-shrinkable refractory member is arranged between the inclined surfaces with both sides thereof in close contact with the inclined surface, the refractory member is composed of an upper refractory member and a lower refractory member, and The lower refractory member is placed in close contact with the lower part of the surface with its lower end positioned above the lower end of the slope, and the upper refractory member is placed on the lower refractory member with a gap between it and the slope. Then, by heating and contracting the lower refractory member, the lower refractory member is moved downward along the slope, and as the lower refractory member moves, the upper refractory member is moved downward, thereby reducing the upper refractory member. It is characterized by the fact that the fireproof member is brought into close contact with the upper part of the slope.

"Embodiment" An embodiment of the method for constructing a sintering furnace of the present invention will be described below with reference to FIGS. 1 to 4.

In these figures, reference numeral 10 indicates a sintering furnace constructed by the sintering furnace construction method of the present invention. This sintering furnace 10 is a tunnel-type furnace, and is composed of a sintering furnace body 11 having a U-shaped cross section, and a sealing part 12 for sealing an opening of this sintering furnace body 11.

The sintering furnace main body 11 is constructed by stacking a large number of rectangular parallelepiped refractory bricks 13 vertically and horizontally, and the inner surfaces of the upper part facing each other have bricks that gradually approach each other as they move downward. Slanted surfaces 14, 14 are formed.

The sealing portion 12 is located between the inclined surfaces 14 and 14.
are arranged with both sides thereof in close contact with the inclined surfaces 14, 14. This sealing part 12 has an inclined surface 14,
Rectangular refractory bricks 16, 16 having inclined surfaces 15, 15 that are in close contact with 14 and whose side surfaces facing each other gradually approach downward; and between these refractory bricks 16, 16, inclined surfaces 15, 15 and a refractory brick (refractory member) 17 placed in close contact with the refractory brick 15.

This refractory brick 17 includes a trapezoid-shaped lower refractory brick (lower refractory member) 18 that is in close contact with the lower part of the inclined surfaces 15, 15, and a lower refractory brick (lower refractory member) 18 that is located above the lower refractory brick 18 and is located at the upper part of the inclined surfaces 15, 15. It is composed of an upper refractory brick (upper refractory member) 19 which is in a trapezoidal shape and which are in close contact with each other.

In addition, the above refractory brick 16, the lower refractory brick 1
8 and the upper refractory brick 19 are made of a heat-shrinkable alumina-based refractory.

In addition, the above-mentioned refractory brick 16, lower refractory brick 1
8 and the dimensions of each part of the upper refractory brick 19 are as shown in FIG. (Unit: mm) The sintering furnace 10 having the above configuration is constructed as follows.

That is, as shown in FIG. 3, after constructing the sintering furnace main body 11, the refractory bricks 16, 16 are brought into close contact with the inclined surfaces 14, 14 formed on the upper inner surface of the sintering furnace main body 11, and , mutually opposing inclined surfaces 15,1 of these refractory bricks 16,16
Between 5 and 5, a lower refractory brick 18 is placed in close contact with the lower part of the inclined surfaces 15, 15 so that its lower end is located above the lower end of the inclined surfaces 15, 15. Then, the upper refractory brick 19 is placed on the lower refractory brick 18 with a gap between it and the inclined surfaces 15, 15. Here, the width of this gap is determined by the shape, size, etc. of each firebrick, but in this example, it is set to 2 mm.

Next, the inside of the sintering furnace body 11 is heated by the heaters 7, 7. Then, the lower refractory brick 18 contracts due to this heat, and as shown in FIG.
5 and 15, and as the lower part refractory brick 18 moves, the upper refractory brick 19 moves downward and comes into close contact with the upper part of the inclined surfaces 15 and 15. In this way, the sintering furnace 10 is constructed.

According to the above method for constructing a sintering furnace, refractory brick 1
Since the lower refractory brick 18 is placed closely under the inclined surfaces 15, 15 of Nos. 6 and 16, with its lower end positioned above the lower end of the inclined surfaces 15, 15,
Even if the lower refractory brick 18 shrinks due to heat contraction,
The lower refractory brick 18 moves downward along the inclined surfaces 15, 15 and stops at an appropriate position on the inclined surfaces 15, 15, so that the lower refractory brick 18 moves downwards along the sintering furnace main body 1.
It will not fall within 1.

In addition, since the lower refractory brick 18 is thinner than the conventional refractory brick 6 shown in FIG. 5, the temperature gradient in the thickness direction of the lower refractory brick 18 is smaller than that of the refractory brick 6. This can prevent cracks from occurring.

Further, the upper refractory brick 19 is placed on the lower refractory brick 18 with a gap between it and the inclined surfaces 15, 15, and the upper refractory brick 19 is tilted by moving downward as the lower refractory brick 18 moves. Since the surfaces 15, 15 are placed in close contact with the upper portions thereof, the heat retention effect within the sintering furnace 10 does not deteriorate compared to the conventional case.

In addition, in the above embodiment, the lower refractory brick 18,
Although the upper refractory brick 19 is made of alumina-based refractory material, the present invention is not limited to this, and may be made of other materials as long as they are heat-shrinkable.

"Effects of the Invention" As explained above, according to the method for constructing a sintering furnace of the present invention, the lower refractory member is placed at the lower part of the inclined surface formed at the opening of the sintering furnace main body. Since the lower refractory member is positioned above the lower end of the lower refractory member and is closely spaced, even if the lower refractory member contracts due to heat contraction, the lower refractory member moves downward along the slope and stops at an appropriate position on the slope. , the lower refractory member will not fall into the sintering furnace main body.

Furthermore, since the lower refractory member is thinner than the conventional refractory brick, the temperature gradient in the thickness direction of the lower refractory member is smaller than that of the conventional refractory brick, thereby preventing the occurrence of cracks due to differences in thermal contraction.

Furthermore, the upper refractory member was placed on the lower refractory member with a gap between it and the slope, and by moving it downward as the lower refractory member moved, the lower refractory member was brought into close contact with the top of the slope. Therefore, the heat retention effect inside the sintering furnace does not deteriorate compared to the conventional method.

[Brief explanation of the drawing]

1 to 4 are for explaining one embodiment of the method for constructing a sintering furnace according to the present invention. FIG. 1 is a schematic perspective view of the sintering furnace, and FIG. Figure 3 is a cross-sectional view showing the process of constructing a sintering furnace; Figure 4 is a cross-sectional view of the sintering furnace;
The figure is a sectional view showing an example of a conventional sintering furnace. 11... Sintering furnace main body, 15... Inclined surface, 18...
...Lower refractory brick (lower refractory member), 19... Upper refractory brick (upper refractory member).

Claims (1)

[Claims] 1 Slanted surfaces that face each other and gradually approach each other toward the bottom are formed on the upper inner surface of the concave sintering furnace body, and between these sloped surfaces, a heat-shrinkable refractory material is formed. In the method for constructing a sintering furnace, in which a member is arranged with both sides thereof in close contact with the inclined surface, the refractory member is composed of an upper refractory member and a lower refractory member, and the lower refractory member is placed at the bottom of the inclined surface. is brought into close contact with the lower end of the sloping surface above the lower end of the inclined surface, and the lower refractory member has a
The upper refractory member is placed with a gap between it and the inclined surface, and then the lower refractory member is heated and contracted to move the lower refractory member downward along the inclined surface. A method for constructing a sintering furnace, characterized in that the upper refractory member is moved downward as the lower refractory member is moved, thereby bringing the upper refractory member into close contact with the upper part of the inclined surface.