JPH0587749B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a tunnel furnace with an improved arrangement of burner groups.

(Prior Art) Conventionally, in a tunnel furnace, burner groups were installed alternately on the left and right furnace walls. Therefore, as shown in FIG. 5, the combustion gas discharged from the burner 1 collides with the furnace wall 2 on the opposite side as shown by the arrow, rises along this wall, and travels along the ceiling 3 to the burner 1. It flowed to the upper part of the furnace wall 2 on the side, and from there it moved downward along the furnace wall 2. In this way, in the conventional tunnel furnace, the hot air flows in a circular manner around the object to be fired 5 placed on the trolley 4, so that the furnace wall 2 is heated more than necessary and the heating effect on the object to be fired 5 is reduced. The drawback was that it was bad.

(Problem to be Solved by the Invention) However, in the field of so-called single kilns, a heating method has been implemented in which hot air from a burner collides at the lower part of the furnace to generate an upward flow of hot air from there. If this method is applied to tunnel furnaces,
Since heating can be performed from the center side of the furnace, that is, from the side of the object to be fired, the furnace wall will not be heated unnecessarily, and an improvement in heating efficiency can be expected.

However, simply causing the combustion gas from the burner to collide at the lower part of the furnace to generate rising hot air will still result in uneven temperature distribution within the furnace, resulting in uneven firing.

Therefore, in this case, as has been attempted in a single kiln, by temporally changing the ratio of the amount of combustion air supplied to both opposing burners, the collision point of the combustion gas discharged from each burner, and thus the hot air It is also possible to try to equalize the temperature distribution in the furnace by temporally moving the rising point of the temperature to the left or right.

However, while the above method was effective in a single kiln, in a tunnel furnace, when moving the collision point of combustion gas toward the furnace wall, rising hot air was not generated smoothly, and the temperature distribution in the furnace was not sufficiently uniform. Therefore, there was a problem in that the occurrence of uneven firing could not be sufficiently prevented.

Therefore, an object of the present invention is to efficiently heat the object to be fired instead of the furnace wall by colliding the combustion gases from both burners located opposite each other in the furnace and generating rising hot air from this, and also to prevent uneven firing. The objective is to provide a tunnel furnace that can prevent the occurrence of

[Structure of the invention]

(Means for Solving the Problems) The tunnel furnace of the present invention has burner groups provided on each of the left and right furnace walls so as to face each other to form a plurality of burner pairs, and each burner discharged from the pair of burners is The collision point of the gas is located below the object to be fired, the amount of combustion air supplied per hour to both burners in the pair is equal, and the aperture ratio of the combustion gas jet ports of both burners in the pair is adjusted. The feature is that by changing each burner pair, the collision points of the combustion gas of each burner pair are set to be dispersed in the width direction of the tunnel furnace along the moving direction of the truck.

Further, in this case, it is preferable to set the opening ratio of the shelf assembly in the moving direction of the cart so that at least a portion thereof is 30% or less.

(Function) Since the combustion gases discharged from the pair of burners collide below the shelf assembly of the truck, rising hot air rises from there, and the material to be burned on the shelf assembly is efficiently heated. In addition, since the collision points of each combustion gas are set to be distributed in the width direction of the tunnel furnace along the moving direction of the cart, each combustion gas is Even if the point of gas collision, that is, the point of generation of rising hot air, does not move temporally in the width direction of the tunnel furnace, uneven firing will not occur.

By the way, according to research by the present inventors, when trying to shift the collision point of combustion gas from the center of the tunnel furnace in the width direction by varying the amount of air supplied to both opposing burners, The collision state of combustion gas became unstable, causing a problem in which sufficient rising hot air was not generated. The reason for this is thought to be that the combustion gas discharged from the burner with a smaller air supply amount among the opposing burners loses the momentum of the combustion gas discharged from the other burner. Further, in a tunnel furnace, since the furnace wind flows, this furnace wind also causes an unstable collision state of the combustion gases. That is, in a tunnel furnace, a large amount of air is forced into the furnace in the cooling zone, firing, etc., and this air flows from the cooling zone, firing, etc. to the tropical side. In this way, the speed of the wind flowing toward the preheating zone was 4 to 4 sec.
It can reach up to about 5m. For this reason, the momentum of the combustion gas discharged from the burner with a smaller air supply of the two opposing burners rapidly decreases, so it has a tendency to be bent downstream by the furnace wind. will be presented.

In contrast, by making the amount of combustion air supplied per hour to both burners in the pair the same, and by changing the aperture ratio of the combustion gas jet ports of both burners in the pair, the collision point of the combustion gas can be shifted. By doing so, sufficient momentum of the combustion gas can be secured, and a stable collision state of the combustion gas can be obtained. In this case, if the opening ratio of at least part of the shelf assembly is set to 30% or less, the force of the wind inside the furnace will be weakened in the combustion gas discharge area, resulting in even more stable combustion gas collision. You will be able to obtain the status.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

Figure 2 shows the structure inside the furnace as seen from the direction of movement of the trolley 11.
2 is constructed, and a product to be fired (not shown) is mounted on the shelf assembly 12, housed in, for example, an H-shaped sagger 13.

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. Here, in this embodiment, in particular, one row of the 14 rows of columns configured on one truck 11 is
The opening ratio of the shelf assembly in the first movement direction is set to be 30% or less.

On the other hand, each of the left and right furnace walls 1 making up the tunnel furnace
7, 18, as shown in FIG.
When the length is 2m, install one at every 1m).
These burner 19 groups are located opposite to each of the left and right furnace walls 17 and 18 so as to constitute a plurality of burner 19 pairs, and the combustion gas discharged from these burners is discharged within the shelf assembly 12, that is, below the products to be fired. The orientation axes are aligned so that there will be a head-on collision. Also,
The amount of combustion air supplied per hour to the two burners 19 provided in pairs on the left and right furnace walls 17 and 18 is equal to each other, but depending on the pair of burners 19, the diameter ratio of the openings through which combustion gas is ejected may be different. differ. That is, as schematically shown in FIG. 1, for the 19 pairs of burners in the first row located on the near side in the figure, the diameter of the burners 19 provided on the furnace wall 17 and the burners provided on the furnace wall 18 are different. For example, the ratio of the diameter of the burner 19 to the burner 19 in the second row is 5:5, and the ratio of the diameter of the burner 19 in the second row to the burner 19 in the third row is 5:5.
For the pair, the aperture ratio is 4:6. In this embodiment, each burner pair 19 is set so that the aperture ratio changes repeatedly in the order shown in FIG.

According to the above configuration, since the burners 19 provided on the left and right furnace walls 17 and 18 face each other, when the burner 19 group is in operation, the combustion gas from the same burner 19 is transferred to the space where the support column 14 is arranged, that is, to be fired. It collides head-on with force below the object, generating rising hot air. Here, the two burners 1 that form a pair
For example, for the 19 pairs of burners in the second row from the front in FIG. 1, the aperture ratio is 5:5, so the discharge speeds of combustion gas are approximately equal. . Therefore,
The collision point of the combustion gases from both burners 19 is located approximately at the center between the two furnace walls 17 and 18, as shown in the figure. However, for the 19 pairs of burners in the first row from the front in the figure, the aperture ratio is 6:4, so
The discharge speed of the combustion gas is slower at the burner 19 provided on the left furnace wall 17 and faster at the burner 19 provided on the right furnace wall 18. Therefore, due to the difference in momentum between the two combustion gases, the collision point is closer to the furnace wall 17 as shown in the figure. Regarding the 19 pairs of burners in the third row, the aperture ratio is 4:6, and the combustion gas discharge speed is slower for the burner 19 on the left side and faster for the burner 19 on the right side. Due to the difference in momentum, the collision point becomes closer to the furnace wall 18, as shown in the figure. Hereinafter, over the entire area where the burner pairs 19 are arranged, the collision point of both combustion gases, that is, the generation point of the ascending hot air, is located so as to be repeatedly shifted in the width direction of the tunnel furnace along the moving direction of the truck 11. (The collision point of the combustion gas is indicated by a circle in Figure 3). In this way, the combustion gas does not flow along the furnace wall, and the objects to be fired are heated by the rising hot air rising from below. This means that the heat can be effectively used to heat the object to be fired, so thermal efficiency can be improved. In addition, as mentioned above, since the point where the rising hot air is generated is repeatedly shifted in the width direction of the tunnel furnace, the objects to be fired can be heated evenly under the circumstances where the cart 11 moves sequentially within the furnace. This allows for even firing. In this case, the amount of combustion air supplied per hour to the two burners 19 in the pair is the same, and the aperture ratio of both burners 19 is made different to create a difference in combustion gas velocity, thereby reducing the collision point. It was made to disperse in the width direction inside the furnace.
According to this, since a sufficient amount of combustion gas on the low-speed side is secured, a stable collision state of combustion gas can be obtained without being overwhelmed by the momentum of the combustion gas on the high-speed side.

Furthermore, as mentioned above, there is a situation in which the wind inside the tunnel furnace flows toward the preheating zone side, but in this embodiment, the opening ratio of the shelf assembly 12 in the moving direction of the cart 11 is 30% or less. Because of this setting, the force of the wind inside the furnace is weaker than before (the conventional opening ratio was about 50% or more). As a result, the combustion gas discharged from each burner 19 is less likely to be bent downstream by the furnace wind, and the combustion gases from both burners 19 forming a pair collide head-on. It becomes like this. Thereby, the collision points of the combustion gas, that is, the generation points of the rising hot air, can be stably dispersed over a wide range in the width direction of the furnace, contributing to uniform heating of the object to be fired.

Note that the arrangement of the collision points of combustion gas, that is, the points of generation of rising hot air, is not limited to that shown in Fig. 3, but may be arranged in a zigzag pattern as shown in Fig. 4, in other words, the positions are distributed in the width direction within the furnace. It is preferable to use an embodiment in which uniform heating of the object to be fired is possible.

〔Effect of the invention〕

As described above, according to the present invention, the object to be fired is heated by the rising hot air rising from the lower part of the furnace, so thermal efficiency is improved compared to the conventional tunnel furnace in which the hot air flows along the furnace wall. Moreover, since the points where the rising hot air is generated are dispersed in the width direction of the furnace, the object to be fired can be heated uniformly. In this case, the amount of combustion air supplied per hour to both burners in the pair is the same, and the collision point of the combustion gas is shifted by changing the diameter ratio of the combustion gas jet ports of both burners in the pair. Therefore, sufficient momentum of the combustion gas can be secured and a stable collision state of the combustion gas can be obtained. Furthermore, when the opening ratio of the shelf assemblies is set so that at least part of it is 30% or less in the moving direction of the cart, the momentum of the furnace air in the combustion gas discharge area can be suppressed, and the rising hot air generation point can be suppressed. can be more stably dispersed in the width direction of the furnace, which has an excellent effect of contributing to more uniform heating of the object to be fired.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, FIG. 1 is a partially cutaway perspective view of a tunnel furnace, FIG. 2 is a vertical sectional view of the tunnel furnace, and FIG. 3 is a combustion gas FIG. FIG. 4 is a view corresponding to FIG. 3 showing a different embodiment of the present invention, and FIG. 5 is a longitudinal sectional view showing a conventional tunnel furnace. In the drawing, 11 is a truck, 12 is a shelf assembly, 14 is a support, 17 is a furnace wall, and 19 is a burner.

Claims (1)

[Claims] 1. A trolley carrying a refractory shelf assembly for placing components to be burnt passes through the furnace, and combustion gas is ejected into the furnace from a group of burners provided on the furnace wall. The burner groups are provided on the left and right furnace walls so as to face each other to form a plurality of burner pairs, and the collision point of each combustion gas discharged from the pair of burners is below the object to be burned. Located in
In addition, by making the amount of combustion air supplied per hour to both burners in the pair the same, and by changing the diameter ratio of the combustion gas jet ports of both burners in the pair, each burner pair is A tunnel furnace characterized in that collision points of combustion gas are set so as to be dispersed in the width direction of the tunnel furnace along the moving direction of the truck. 2. The tunnel furnace according to claim 1, wherein at least part of the opening ratio of the shelf assembly is set to 30% or less in the moving direction of the truck.