JPH0554037B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a tunnel furnace and a firing method in a tunnel furnace that improves the temperature distribution in the furnace.

(Prior Art) Conventionally, in tunnel furnaces, burner groups are often installed alternately on the left and right furnace walls. Therefore, as shown in Figure 3, the burner 1
The combustion gas discharged from the furnace collides with the furnace wall 2 on the opposite side as shown by the arrow, rises along this, flows along the ceiling 3 to the upper part of the furnace wall 2 on the burner 1 side, and from here the It was moving downward along the furnace wall 2.

(Problem to be Solved by the Invention) However, in the tunnel furnace configured as described above, the hot air tends to flow around the 5 groups of objects to be fired placed on the trolley 4. Heat transfer to the center of the 5th group is poor, and the 4th group
As shown in the temperature distribution diagram in the figure, there was a drawback that a so-called cold spot was generated in the center. Incidentally, although FIG. 4 shows the temperature distribution in the preheating zone of the tunnel furnace, the temperature distribution in the fired body also exhibits a similar tendency. This uneven temperature distribution in the preheating zone and firing zone causes uneven firing of the object to be fired.

On the other hand, a heating method has also been considered in which the burners are placed opposite each other and the combustion gas from each burner collides with each other at the center of the lower part of the furnace to generate an upward flow of hot air from there. However, in this case, much of the kinetic energy of the combustion gas is wasted and the upward force of the hot air is weak, so it is difficult to sufficiently eliminate the cold spot in the center of a tunnel furnace, especially in a tunnel furnace with a large height inside the furnace. This was insufficient to achieve uniform temperature distribution in the furnace.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a tunnel furnace and a firing method using a tunnel furnace, which can make the temperature distribution in the furnace uniform.

[Structure of the Invention] (Means for Solving the Problems) The tunnel furnace and the firing method in the tunnel furnace of the present invention are characterized in that a trolley carrying a refractory shelf assembly for placing objects to be fired passes through the inside. In a tunnel furnace configured to blow out burning gas downward from the group of burners provided on each of the left and right furnace walls, the burning gas ejected from the burners is received on a truck and directed upward. It is characterized by the provision of a guiding wind direction changing member.

In this case, a ventilation gap is provided above the wind direction changing member in the group of objects to be fired placed on the shelf assembly,
When the dimension D of the ventilation gap is defined as the gap dimension d ₁ between the group of objects to be fired and the furnace wall, it is desirable to set it so that D≧2d ₁ .

(Function) In the operation of a tunnel furnace, combustion gas is injected downward from the burner group provided on the furnace wall toward the group of objects to be fired. This combustion gas collides with a wind direction changing member installed on the truck, and is guided upward by this. Therefore, the kinetic energy of the combustion gas injected from the burner is not wasted, but is effectively used to create a strong rising hot air, and the central part of the group of objects to be fired is also efficiently heated. As a result, the temperature distribution inside the furnace becomes uniform.

In addition, if a ventilation gap is actively provided above the wind direction changing member in the group of objects to be fired placed on the shelf assembly, the momentum of the rising hot air will not be weakened, and the temperature distribution inside the furnace will be improved. It is more effective in making the temperature uniform. The hot air that reaches the ceiling of the furnace through the ventilation gap is divided into two parts, left and right, at the ceiling and returns to the burner side through the gap between the objects to be fired and the furnace wall. Therefore, when the ventilation gap dimension D is defined as the gap dimension between the group of objects to be fired and the furnace wall as d ₁ , D
When set to ≧2d ₁ , a sufficient cross-sectional area of the ascending hot air flow path is ensured, so that it is possible to more reliably prevent the momentum of the ascending hot air from being weakened.

(Example) A first example of the present invention will be described below with reference to FIG.

Figure 1 shows the structure inside the furnace as seen from the moving direction of the cart 11.
2 is constructed, and a large number of, for example, H-shaped pots 13, which house objects to be fired (not shown) inside, are stacked on the shelf assembly 12. Here, one set of 13 groups of pots stacked in multiple tiers is referred to as a pot stack S. As is well known, each pot stack S is arranged vertically and horizontally with gaps between each other. Six pot stacks S are erected on the cart 11 in its width direction.

The structure of the shelf assembly 12 is as follows. A plurality of flat supports 14 are arranged side by side on the trolley 11, and a plurality of rows of supports 14 are arranged on one trolley 11.
A line is formed. A horizontal support bar 15 is placed on each of the 14 rows of columns, and these horizontal support bars 15
A plurality of vertical support bars 16 are combined on top of the bar in a direction perpendicular thereto. Therefore, according to this shelf assembly 12, the horizontal support bar 15 and the vertical support bar 1
The hot air in the furnace can flow up and down through the combined parts 6, and the hot air can also flow back and forth and left and right (in the moving direction of the cart and in the orthogonal direction thereof) between the respective supports 14.

On the other hand, each of the left and right furnace walls 1 making up the tunnel furnace
7 and 18, a plurality of burners 19 are provided intermittently at the bottom along the moving direction of the trolley 11 (for example, when the length of the trolley 11 is approximately 2 m,
Place one at a time). these burners 1
9, the ejection direction of the combustion gas is set so that the ejected combustion gas is ejected above the truck 11 and below the group of objects to be fired, that is, toward the installation area of the group of columns 14. Note that the discharge speed of the combustion gas is 80 m/sec or more in this embodiment.

Now, on the upper surface of the truck 11, a wind direction changing member 20 made of a refractory material is installed. This has a long triangular prism shape and is installed in the center of the truck 11 parallel to the left and right furnace walls 17 and 18, and is located below the shelf assembly 12 and, therefore, the group of objects to be fired. and,
As shown in FIG. 1, the 13 groups of pots storing objects to be fired are stacked so as to positively secure a ventilation gap 21 between adjacent pot stacks S above the wind direction converting member 20. . The dimension D of the ventilation gap 21 is set so that D≧2d ₁ , where d ₁ is the dimension between the pot stack S located at the outermost position of the cart 11 and the oven walls 17, 18. Furthermore, the gap size d ₂ between each pot stack S is smaller than d ₁ , and in this example, d ₁ ≒100 mm, d ₂ ≒80 mm.
It is.

According to the above configuration, when the group of burners 19 is in operation, combustion gas is discharged from each burner 19 at high speed, and this gas is discharged from the wind direction converting member 2 installed on the trolley 11.
collides with 0. Since this wind direction changing member 20 has slopes on the left and right sides, the combustion gas is guided by the slopes and changes its direction upward as shown by the arrow in FIG. 1, becoming a strong rising hot wind. This rising hot air passes through the ventilation gap in the group of objects to be fired, that is, the ventilation gap 21 between the central pot stacks S, and reaches the ceiling of the tunnel furnace. It moves toward the 17 and 18 sides and descends near each furnace wall 17 and 18.
In consideration of such hot air circulation path, in this embodiment, the dimension D of the ventilation gap 21 is set to the dimension d between the bowl stack S located at the outermost position of the cart 11 and the furnace walls 17 and 18. Since it is set to more than twice ₁ , a sufficient cross-sectional area for the rising hot air is ensured, and the hot air is circulated without weakening its momentum. As a result, a sufficient amount of heat is supplied to the center of the group of objects to be fired by the rising hot air, and even if the vertical dimension inside the furnace is high, the amount of heat generated in the center of the group of objects to be fired will tend to increase. It is possible to eliminate cold spots and make the temperature distribution in the furnace uniform.

In the above embodiment, since the ventilation gap 21 between the pot stacks S is ensured to be particularly wide above the wind direction changing member 20, the uniformity of the temperature distribution in the furnace is significantly promoted. If the wind direction changing member 20 is provided to guide the wind upward, it is not necessary to ensure a particularly wide ventilation gap above the winding. FIG. 2 shows a second embodiment in which the gap size between the pot stacks S is kept constant as in the conventional case. For the sake of brevity, the same parts as in the first embodiment are given the same reference numerals and their explanations are omitted. However, from the temperature distribution curve drawn over the same figure, it is clear that compared to the conventional configuration shown in Fig. 4, It can be seen that the temperature distribution inside the furnace is sufficiently improved.

The burners may be arranged in a facing arrangement in which the left and right burners face each other, or in a staggered arrangement in which the left and right burners are alternated. Further, the wind direction converting member does not necessarily have to be triangular prism-shaped, but may be semicircular, for example, or may be formed by stacking refractory bricks in a pyramid shape in the center of the truck.

[Effects of the Invention] As described above, according to the present invention, the combustion gas ejected from the burner is guided upward by the wind direction changing member, so that rising hot air with a sufficient velocity is generated in the center of the furnace. As a result, a sufficient amount of heat can be supplied to the central part of the group of objects to be fired, and the temperature distribution in the furnace can be made uniform. In addition, if a ventilation gap is actively provided within the group of objects to be fired above the wind direction changing member, and the size of the gap is at least twice the size of the gap between the group of objects to be fired and the furnace wall, the increase in Since a sufficient cross-sectional area of the hot air flow path is ensured, the temperature distribution within the furnace can be made more uniform.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a tunnel furnace according to a first embodiment of the present invention, and FIG. 2 is a view corresponding to FIG. 1 according to a second embodiment of the present invention. FIG. 3 is a longitudinal sectional view showing a conventional tunnel furnace, and FIG. 4 is a temperature distribution diagram showing the temperature distribution inside the conventional tunnel furnace. In the drawing, 11 is a trolley, 12 is a shelf assembly, 17, 18
is a furnace wall, 19 is a burner, 20 is a wind direction changing member,
21 is a ventilation gap.

Claims (1)

[Scope of Claims] 1. A cart carrying a refractory shelf assembly for placing the objects to be fired passes through the interior, and directs downward from the burner groups provided on the left and right furnace walls. What is claimed is: 1. A tunnel furnace configured to blow out combustion gas, characterized in that a wind direction changing member is provided on the cart for receiving the combustion gas ejected from the burner and guiding it upward. 2. A ventilation gap is provided above the wind direction changing member in the group of objects to be fired placed on the shelf assembly, and the dimension D of the ventilation gap is the distance between the group of objects to be fired and the furnace wall. 2. The tunnel furnace according to claim ₁ , wherein D≧2d ₁ , where d1 is the gap size of the tunnel furnace. 3 A trolley carrying refractory shelves for placing the objects to be fired passes through the interior, and combustion gas is ejected downward from the burner groups installed on the left and right furnace walls. In the tunnel furnace of the configuration,
A firing method in a tunnel furnace, characterized in that the cart is run in the tunnel furnace with a wind direction changing member installed on the cart for receiving combustion gas from the burner and guiding it upward.