JPH0474298B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for firing oxidized tiles using a tunnel furnace.

(Prior art) The firing of oxidized tiles using a tunnel furnace is described, for example, in Minoru Tanaka's "Clay Tile Handbook" (November 25, 1980).
As shown in Gihodo Publishing Co., Ltd., p. 368, it has been known for a long time that tunnel furnaces for making oxidized roof tiles have a pressure inside the furnace that is 0.1 to 0.3 mmAq higher than atmospheric pressure. The furnace was being operated. This is due to structural constraints in the case of tunnel furnaces for producing oxidized roof tiles, such as the distance between the exit door of the furnace and the tip of the cart to avoid collisions of at least 50 mm, and the incomplete sand seal. This is because the seal between the bottom part of the trolley and the inside of the furnace is incomplete, and if the pressure inside the furnace is increased any further, heat will tend to flow to the bottom of the trolley, increasing troubles such as seizure of the wheels of the trolley. It was hot. Due to the low pressure inside the furnace, when firing oxidized tiles using a conventional tunnel furnace, the temperature distribution inside the furnace tends to be uneven, and the yield is only about 80%. The variation R in the water absorption rate of tiles also showed a large value of 1.0%.

(Problem to be solved by the invention) The present invention solves these conventional problems, and
This was completed with the aim of creating a method for firing oxidized tiles using a tunnel furnace, which can be used to fire oxidized tiles with a high yield and with less uneven temperature distribution.

(Means for Solving the Problems) The present invention maintains the pressure inside the tunnel furnace for firing oxidized tiles at a pressure higher than atmospheric pressure by 1.0 mmAq or more, and the pressure under the cart is lower than the pressure inside the furnace by 0.5 mmAq.
This method is characterized in that the oxidized roof tiles are fired while maintaining the temperature at a temperature not lower than that. Further, in the present invention, it is preferable that a flow stop plate is provided at the bottom of the car of the tunnel furnace and that the pressure under the car is adjusted by injecting air into the compartment partitioned by the flow stop plate. Furthermore, it is preferable to adjust the pressure under the cart by keeping the gap between the exit door of the tunnel furnace and the tip of the cart at 20 mm or less and preventing airflow from flowing under the cart from this gap.

As described above, the reason why the pressure inside the furnace is set to be 1.0 mmAq or more higher than atmospheric pressure in the present invention is because a sufficient temperature distribution uniformity effect cannot be obtained below this pressure. Also, the pressure difference between the pressure inside the furnace and the pressure below the trolley is
The reason why it is set to 0.5 mmAq or less is because if it exceeds this value, the high temperature atmosphere inside the furnace will get under the cart, making it easy to cause damage to the bottom of the cart. In addition, the pressure inside the furnace is preferably atmospheric pressure + 1 to 5 mmAq for furnace operation.
Further, it is preferable to maintain the pressure inside the furnace higher than the pressure under the truck.

The present invention will be explained in more detail below with reference to the drawings.

Figure 1 Furnace body 1 of tunnel furnace for firing ibushi tiles
is a horizontal cross-sectional view, where 2 is the entrance, 3
is the outlet, and the oxidized tile material is loaded on a cart 4 as shown in FIG. 2, and fired while being intermittently moved inside the furnace body 1 from the inlet 2 to the outlet 3. , immediately after exiting exit 3, a fumigation box is placed over the roof to produce oxidized roof tiles, as in the past. The tunnel furnace shown in the embodiment of the present invention is a tunnel furnace with a length of approximately 60 m that can accommodate 20 carts each having a length of 3 m, and is operated on a 40-minute schedule.

In the embodiment of the present invention, as shown in FIG. 2, flow prevention plates 7 are provided in the lower part of the furnace body 1 at intervals of several carts 4, and two to three blocks are provided near the outlet. 5 to 5 per unit and in other parts
It is preferable to provide a flow stop plate 7 for every six units.
This flow stop plate 7 increases the flow resistance in the area under the truck, making it possible to maintain a high pressure under the truck. As shown in the diagram, the flow prevention plate 7
is erected from the floor so as to fill most of the cross section of the trolley 4 excluding the wheels 8 and the like.

In the present invention, the pressure inside the furnace is maintained at a pressure higher than atmospheric pressure by, for example, 1.5 mmAq, and by injecting air into the lower part of the truck 4 of the furnace body 1, the pressure under the truck is increased to 1.1 mmAq higher than the atmospheric pressure, for example. Maintain mmAq high pressure. As shown in FIG. 1, the air injection nozzle 5 for this purpose is provided on the floor or lower part of the side wall of the furnace body within the compartment partitioned by the flow stop plate 7. An air suction nozzle 6 for sucking air is provided closer to the inlet than the air injection nozzle 5. The reason why air is injected from the side near the outlet 3 and air is sucked from the inlet 2 side is because the gradient of the pressure inside the furnace is higher on the outlet 3 side and the air is sucked from the inlet 2 side.
This is because the pressure is lower on the side, and it is important to adjust the pressure under the truck accordingly. Note that it is preferable to provide more air injection nozzles 5 near the outlet.
By injecting air into the lower part of the truck 4 in this manner, the pressure under the truck can be increased freely.

In order to increase the pressure under the carriage, it is preferable to keep the gap between the exit door 9 of the tunnel furnace and the tip of the carriage 4 at 20 mm or less to prevent airflow from flowing under the carriage. For this purpose, after stopping the cart 4, push the exit door 9 of the tunnel furnace toward the cart 4 so that the distance between the door 9 and the tip of the cart 4 is 20 mm or less, or after stopping the cart 4, It is possible to adopt a method of slowly advancing the robot toward the exit door 9. If this distance exceeds 20 mm, it will be difficult to effectively prevent airflow from flowing under the truck from this distance.

In the present invention, by such a means, even when the pressure inside the furnace is set to be 1.0 mmAq or more higher than atmospheric pressure, the pressure below the bogie can be maintained so as not to fall below the furnace pressure by 0.5 mmAq or more, and the high temperature It is possible to prevent the atmosphere inside the furnace from entering the truck and causing the wheels of the truck 4 to seize. In addition, by increasing the pressure inside the furnace much higher than before, it is possible to make the temperature distribution inside the furnace more uniform, which greatly increases the product yield from about 80% to 90-95%. can be done. Furthermore, the variation R in the water absorption rate of fired roof tiles is an indicator of the uniformity of temperature distribution.
can also be reduced from the previous 1.0% to 0.5%.

(Effects of the Invention) As is clear from the above description, the present invention maintains the pressure inside the tunnel furnace for firing oxidized tiles at a pressure higher than atmospheric pressure by 1.0 mmAq or more, while reducing the pressure under the cart inside the furnace. By ensuring that the pressure does not fall below 0.5 mmAq, the uniformity of the temperature distribution inside the furnace is improved, and damage to the area under the cart due to the high temperature atmosphere inside the furnace getting under the cart is prevented. It was extremely successful. According to the present invention, not only can the product yield be greatly improved, but also the variation in quality of fired ibushi roof tiles can be reduced by half compared to the conventional method. Therefore, the present invention greatly contributes to the development of industry as a method for firing oxidized roof tiles using a tunnel furnace that eliminates the problems of the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a horizontal sectional view of a tunnel furnace illustrating an embodiment of the present invention, and FIG. 2 is a vertical sectional view of the lower part of the truck. 1: Furnace body, 4: Cart, 5: Air injection nozzle,
6: Air suction nozzle, 7: Stop plate.

Claims (1)

[Scope of Claims] 1. Maintaining the pressure inside the furnace of a tunnel furnace for firing oxidized tiles at a pressure higher than atmospheric pressure by 1.0 mmAq or more, and maintaining the pressure under the cart so that it does not fall below the pressure inside the furnace by 0.5 mmAq or more. A method for firing oxidized tiles using a tunnel furnace, which is characterized by firing oxidized tiles. 2. The oxidized tile for a tunnel furnace according to paragraph 1, in which a flow stop plate is provided at the bottom of the tunnel furnace car and the pressure under the car is adjusted by blowing air into the compartment partitioned by the flow stop plate. firing method. 3. Between the exit door of the tunnel furnace and the tip of the trolley.
The method for firing oxidized tiles using a tunnel furnace according to item 1, wherein the pressure under the truck is adjusted by keeping the pressure at 20 mm or less and preventing airflow from flowing under the truck from this gap.