JPH09318271A - Tunnel furnace and method for heating and cooling baked item using the furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tunnel furnace capable of changing a baking curved line pattern in the longitudinal direction of the furnace, and not generating any irregular baking and cooling crack is a sintered material. SOLUTION: A tunnel furnace 1 in which a baked material 6 is passed from one inlet port to the other outlet port is constructed such that each of some burners 11A,..., 11B... is spaced apart in a predetermined interval along a moving direction of the baked material 6 within the tunnel furnace 1, each of a pair of burners 11A, 11B positioned at an opposing surface perpendicular to a moving direction of the baked material 6 is controlled in such a way that when one of them is kept at a state where combustion gas is injected from the burner into the furnace, the other discharges the combustion gas from in the furnace and them heat flow in the furnace is flowed in a width of the furnace. Accordingly, it is possible to perform a fine temperature adjustment within a range of each of the preheating-baking-cooling processes for the baked material 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel furnace in which a material to be fired moves from one inlet to the other outlet, and a tunnel furnace capable of performing temperature control according to the firing conditions of the material to be fired. The present invention relates to a method for heating and cooling an object to be fired using the same.

[0002]

2. Description of the Related Art For example, roof tiles, tiles, and other ceramic product manufacturers are actively promoting rationalization of production due to the recent stagnation of domestic demand, but each product has its own characteristics in addition to the improvement in productivity. We are working on a production plan for high-quality, low-volume, high-volume items. Taking the tile industry as an example, the weaknesses of buildings with traditional roof tiles have been highlighted in the recent earthquake disaster, and among producers, we have focused on the development of "lightweight tile" products using new raw materials. There is. Above all, the improvement of the function of the firing tunnel furnace, which is the core of the production process, is the most important issue.

FIGS. 4 and 5 show an example of a conventional tunnel furnace of this type, FIG. 4 is a plan view showing a part of the tunnel furnace in a see-through state, and FIG. It is the center sectional view which followed. As shown in FIGS. 4 and 5, the tunnel furnace 1 is generally divided into a preheating zone 1A, a firing zone 1B, and a cooling zone 1C from one inlet 1a toward the other outlet 1b. A plurality of burners 2 are arranged on the left and right sides of the furnace wall of the tunnel furnace 1 in the central burning zone 1B, and the burning gas ejected from the plurality of burners 2 causes the burning zone 1B to reach a high temperature. Held in.

On the other hand, in the preheating zone 1A of the entrance 1a of the tunnel furnace 1, exhaust pipes 3a, 3b are provided on the left and right sides and the upper side of the furnace wall.
Are arranged so as to draw in the combustion gas ejected to the central firing zone 1B, and the fired product can be preheated by generating a temperature gradient with respect to the central firing zone 1B.

In the cooling zone 1C, an air curtain is formed by arranging a cooling air injection pipe 4 above the furnace wall near the firing zone 1B to form an air curtain, and exhaust pipes 5 on the left and right of the furnace wall near the outlet.
Is arranged and the cooling air sent into the cooling zone 1C by the driving pipe 4 is exhausted.

In such a structure, the trolley 7 on which the material to be fired 6 is placed is moved and passed sequentially from one inlet 1a of the tunnel furnace 1 to the other outlet 1b thereof, whereby a temperature gradient is generated. In the formed preheating zone 1A, the article to be fired 6 is preheated, and when the article to be fired 6 passes through the firing zone 1B, the article to be fired 6 is fired by the combustion gas ejected from the burner 2. Then, the material 6 to be fired that has been subjected to the firing treatment is cooled in the cooling zone 1C by the cooling air fed by the driving pipe 4, and is fed out from the outlet 1b of the tunnel furnace 1.

[0007]

By the way, in the above-mentioned conventional tunnel furnace, the combustion gas from the burner is
It is designed to be discharged from the inlet side of the truck to form a preheating zone due to the temperature gradient on the inlet side. Combustion gas flows from the high temperature side of the furnace temperature in the longitudinal direction (reactor length direction) of the furnace. It was basically flowing to the low temperature side.

Therefore, in the conventional tunnel furnace, since the installation sites of the preheating zone, the firing zone and the cooling zone are fixed, there is a limit in changing the temperature change pattern in the furnace length direction, that is, the so-called firing curve pattern, Therefore, there was a technical problem that it had to be fixed only in the baking of almost a single variety or a variety similar to it.

Further, since the flow of the combustion exhaust gas is in the furnace length direction, the temperature distribution between both wall sides and the center of the furnace becomes non-uniform in the width direction of the furnace, resulting in uneven burning of the material to be fired. Had.

Further, a temperature difference is locally generated due to the action of the air curtain at the portion where the final zone of firing is switched to the cooling zone, and cooling cracks (cracks) occur on the article to be fired located outside.
There is a technical problem that is likely to occur.

The present invention has been made in order to solve the technical problems of the conventional ones described above, and makes it possible to change the firing curve pattern in the furnace length direction, thereby causing uneven firing and cooling sharpness on the object to be fired. It is an object of the present invention to provide a tunnel furnace which does not generate and a heating and cooling method of a material to be fired using the tunnel furnace.

[0012]

A tunnel furnace according to the present invention made to achieve the above object is a tunnel furnace in which a material to be fired moves from one inlet to the other outlet. A plurality of burners are arranged at a predetermined interval along the moving direction of the object to be burned, and one of the burners forming a pair located on the facing surface perpendicular to the moving direction of the object to be burned is one of the combustion gas. Is controlled so that the other side is in a state of exhausting combustion gas when it is in the state of jetting, so that the heat flow in the furnace flows in the width direction of the furnace.

It is desirable that one of the burners that is in a state of ejecting the combustion gas is constructed so that the combustion temperature can be controlled individually, and that the pair of burners ejects the combustion gas. It is desirable to be configured such that the operating state and the exhausting state of the combustion gas can be switched alternately.

The pair of burners is preferably arranged on the left and right of the furnace wall, and the burners radiate heat when ejecting combustion gas and store heat when exhausting the combustion gas. It is desirable to have a heat storage exchanger that operates.

The tunnel furnace according to the present invention made to achieve the above object is a tunnel furnace in which a material to be burned passes from one inlet toward the other, and the moving direction of the material to be burned in the tunnel furnace is A plurality of burners are arranged at predetermined intervals along with, and one of the burners forming a pair positioned on the facing surface perpendicular to the moving direction of the object to be fired is in a state of ejecting combustion gas. At the same time, the other is controlled to exhaust the combustion gas so that the heat flow in the furnace flows in the width direction of the furnace and the fuel is supplied to the burner arranged near the exit of the tunnel furnace. It is configured such that it can be shut off and a cooling zone is formed.

In order to achieve the above object, the method for heating an object to be fired in a tunnel furnace according to the present invention is a method for heating an object to be fired in a tunnel furnace in which the object to be fired moves from one inlet to the other outlet. In the heating method, at a predetermined interval along the moving direction of the material to be fired in the tunnel furnace, and on the facing surface perpendicular to the moving direction of the material to be fired,
When one is in the state of ejecting the combustion gas, the other is in the state of exhausting the combustion gas, and a pair of burners is arranged to individually control the combustion temperature of each burner according to the firing conditions of the object to be fired. The object to be fired is heated.

The method for cooling an object to be fired in a tunnel furnace according to the present invention, which has been made in order to achieve the above-mentioned object, is an object to be fired in a tunnel furnace in which the object to be fired passes from one inlet toward the other outlet. In the cooling method, at a predetermined interval along the moving direction of the object to be fired in the tunnel furnace, and on the facing surface perpendicular to the moving direction of the object to be fired,
When one is in a state of ejecting combustion gas, the other is arranged as a pair of burners that will be in a state of exhausting combustion gas so that the heat flow in the furnace flows in the furnace width direction,
The supply of fuel to each burner arranged near the exit of the tunnel furnace is cut off, and only the air is supplied to form a cooling zone to cool the material to be fired.

In order to achieve the above-mentioned object, the method for heating and cooling an object to be fired in a tunnel furnace according to the present invention is the object to be fired in a tunnel furnace in which the object to be fired moves from one inlet to the other outlet. In the method for heating and cooling objects, a predetermined interval is set along the moving direction of the object to be fired in the tunnel furnace, and one of them is a state in which the combustion gas is ejected to the facing surface perpendicular to the moving direction of the object to be fired. At one time, the other burner is arranged so that the other one exhausts combustion gas, and the combustion temperature of each burner is individually controlled according to the firing conditions of the object to be fired, and the object to be fired is heated. The supply of fuel to each burner arranged near the exit of the tunnel furnace is cut off, and only the air is supplied to form a cooling zone, so that the material to be fired is cooled.

In the tunnel furnace configured as described above and the method for heating a material to be fired using the tunnel furnace, each pair of burners located on the opposing surfaces perpendicular to the moving direction of the material to be fired is one of them. Is configured to eject the combustion gas when the other is in the state of ejecting the combustion gas, the combustion temperature of each burner can be controlled individually according to the firing conditions of the object to be fired. It is possible.

Further, in the tunnel furnace configured as described above and the method for cooling a material to be fired using the tunnel furnace, the combustion temperature of each burner is individually controlled, and each burner arranged near the exit of the tunnel furnace. Since it is possible to cut off the fuel supply to the furnace and make only the air flow in the furnace width direction, it becomes possible to make the temperature distribution in the furnace width direction uniform and prevent local cooling during cooling. It is possible to improve the yield by eliminating burning unevenness and cooling sharpness.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A tunnel furnace according to the present invention will be described below with reference to the embodiments shown in the drawings. FIG.
Is a plan view showing a fracture of a part of a tunnel furnace,
Further, FIG. 2 is a side view along the furnace length direction. Further, FIG.
FIG. 2 is a cross-sectional view showing a portion AA in FIG. 1 in an enlarged manner. 1 to 3, parts common to those of the conventional device shown in FIGS. 4 and 5 are designated by the same reference numerals,
Detailed description thereof will be omitted.

1 to 3, a burner is provided in the tunnel furnace 1 so as to face each other on the left and right sides of the furnace wall at a predetermined interval along the moving direction of the material to be burned 6 in the tunnel furnace 1. 11A and 11B are arranged. The pair of burners 11A and 11B, which are located on opposite surfaces perpendicular to the moving direction of the object to be fired 6, are arranged such that when one is in a state of ejecting combustion gas, the other is in a state of exhausting combustion gas. It is configured.

That is, as shown in FIG. 3, a branch pipe 13A is connected to one of the pair of burners 11A through a heat storage box 12A, and the other pair of burners 1 is also connected.
A branch pipe 13B is connected to 1B via a heat storage box 12B. And a pair of branch pipes 13A and 13B
Each of the base ends of the two is connected to a four-way switching device 14 having a switching damper 14a housed therein. A combustion air supply pipe 15 and a combustion air exhaust pipe 16 are connected to the four-way switching device 14.

Therefore, in the four-way switching device 14, the combustion air supplied from the combustion air supply pipe 15 is supplied to one burner 11A via the branch pipe 13A and the heat storage box 12A in accordance with the rotating direction of the switching damper 14a. To be done. An air flow returning to the four-way switching device 14 via the heat storage box 12B and the branch pipe 13B is formed in the other pair of burners 11B, and the exhaust gas via the branch pipe 13B is exhausted by the four-way switching device 14 to the exhaust pipe. It is configured to be delivered to 16.

Although not shown, each burner 11A, 11B is configured to be supplied with gas as fuel, and the amount of gas as fuel supplied to each burner 11A, 11B is It is designed to be adjustable and the combustion temperature can be controlled individually. Also, each burner 11A, 11B and each branch pipe 13A,
Heat storage box 12A, 1 connected to 13B
A heat storage body (not shown) made of ceramics or the like is housed in each of the 2B, and the heat storage body radiates heat when ejecting combustion gas, and stores heat when inhaling combustion gas. It is designed to act as a body.

Therefore, in FIG. 3, the switching damper 14a housed in the four-way switching device 14 is rotated to switch the switching damper 14a in the opposite direction to that shown in FIG. Is formed. At this time, gas as fuel is supplied to each burner 11A or 11B according to the rotational position of the switching damper 14a of the four-way switching device 14, and an ignition device (not shown) operates to burn one of the pair of burners. When the gas is ejected, the other is controlled to exhaust the combustion gas. Therefore, the combustion gas is ejected and exhausted between the pair of opposing burners, so that the heat flow in the furnace flows in the width direction of the furnace.

By the operation of the four-way switching device 14, the pair of burners is configured to alternately switch between a state of ejecting combustion gas and a state of exhausting combustion gas. By adjusting the amount of gas supplied to each pair of burners 11A or 11B and the amount of combustion air supplied from the combustion air supply pipe 15, respectively, as shown in FIG. A preheating zone and a firing zone 1D for gradually heating the article to be fired 6 are formed toward the portion. Also in the firing region, the temperature region can be set arbitrarily by adjusting the gas supply amount to the pair of burners 11A or 11B and the combustion air supply amount supplied from the combustion air supply pipe 15, respectively. Therefore, the firing curve pattern in the furnace length direction can be changed very easily.

Further, the pair of burners 11 is controlled by cutting off the supply of fuel (gas) to each of the burners 11A and 11B arranged near the exit 1b of the tunnel furnace.
Between A and 11B, only air is circulated, so that a cooling zone 1E for the article to be fired 6 is formed as shown in FIG.

In this case, the amount of fuel (gas) supplied to each of the burners 11A and 11B existing from the central burning zone to the cooling zone 1E is adjusted so as to gradually decrease, so that the burned material 6 can be drastically reduced. It is possible to solve problems such as uneven baking, cooling sharpness, etc., on the object to be fired 6 without giving a special cooling effect.

[0030]

As is apparent from the above description, according to the tunnel furnace of the present invention and the method for heating an object to be fired using the tunnel furnace, the pair of members located on the opposing surfaces perpendicular to the moving direction of the object to be fired are used. Each of the burners is configured so that when one of them is in the state of ejecting combustion gas, the other is in the state of exhausting combustion gas. It is possible to control the temperature individually. Therefore, it is possible to finely adjust the temperature in each range of the preheating-baking-cooling process, and it is extremely quick to respond to conditions such as the properties and shape of the raw material of the material to be baked, or the production amount. A tunnel furnace can be provided.

As described above, since the firing curve pattern in the furnace length direction can be easily set, for example, it is possible to immediately deal with a small amount of products of various types. Moreover, the temperature distribution in the furnace width direction can be made uniform by making the flow of the combustion exhaust gas in the furnace width direction, and further by changing the flow in the furnace width direction to the left and right directions, and therefore the object to be fired It is possible to prevent the occurrence of uneven burning.

Further, according to the tunnel furnace of the present invention and the method of cooling the object to be fired using the tunnel furnace, the fuel supply to each burner is gradually reduced and shut off as the outlet of the tunnel furnace is approached. As described above, it becomes possible to make the temperature distribution in the furnace width direction uniform and prevent local cooling during cooling. Therefore, it is possible to reduce the degree of occurrence of cooling cracks on the object to be fired, not only to improve the yield, but also to support the object to be fired resulting from a sudden temperature change, such as refractory columns and shelves. It is possible to greatly reduce the damage of the tool material of.

Further, according to the tunnel furnace of the present invention and the heating / cooling method of the object to be fired using the tunnel furnace, both effects of the above-described heating method and cooling method can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a tunnel furnace according to the present invention with a part thereof cut away.

FIG. 2 is a side view along the furnace length direction of the tunnel furnace shown in FIG.

FIG. 3 is a cross-sectional view showing a portion AA in FIG. 1 in an enlarged manner.

FIG. 4 is a plan view showing a part of a conventional tunnel furnace in a see-through state.

5 is a central sectional view taken along the furnace length direction of the tunnel furnace shown in FIG.

[Explanation of symbols]

 1 Tunnel Furnace 1a Inlet 1b Outlet 6 Burned Material 7 Truck 11A Burner 11B Burner 12A Heat Storage Box 12B Heat Storage Box 13A Branch Pipe 13B Branch Pipe 14 Four-way Switching Device 14a Switching Damper 15 Combustion Air Supply Pipe 16 Combustion Air Exhaust Pipe

Claims (9)

[Claims] 1. A tunnel furnace in which a material to be fired moves from one inlet to the other outlet, and a plurality of burners are arranged at predetermined intervals along a moving direction of the material to be fired in the tunnel furnace. , And each of the paired burners located on the facing surface perpendicular to the moving direction of the object to be fired is controlled so that when one is in the state of ejecting combustion gas, the other is in the state of exhausting combustion gas. The tunnel furnace is characterized in that the heat flow in the furnace flows in the width direction of the furnace. 2. The tunnel furnace according to claim 1, wherein one of the burners in a state of ejecting the combustion gas is configured so that the combustion temperature can be controlled individually. 3. The pair of burners is configured such that a state of ejecting combustion gas and a state of exhausting combustion gas can be switched alternately. Tunnel furnace described in 2. 4. The tunnel furnace according to claim 1, wherein the paired burners are arranged on the left and right of the furnace wall. 5. The heat exchanger according to claim 1, wherein each of the burners is provided with a heat storage exchanger that radiates heat when ejecting combustion gas and stores heat when ejecting combustion gas. Tunnel furnace described in any of. 6. A tunnel furnace in which a material to be fired passes from one inlet toward the other outlet, and a plurality of burners are arranged at predetermined intervals along a moving direction of the material to be fired in the tunnel furnace. The burners, which are paired with each other and face each other in the direction perpendicular to the moving direction of the object to be burned, are controlled so that when one is in the state of ejecting combustion gas, the other is in the state of exhausting combustion gas. Thus, the heat flow in the furnace is made to flow in the width direction of the furnace, and the fuel supply to the burner arranged near the exit of the tunnel furnace is cut off to form the cooling zone. A tunnel furnace characterized by the fact that 7. A method for heating an object to be fired in a tunnel furnace, wherein an object to be fired moves from one inlet to the other outlet, wherein a predetermined interval is provided along a moving direction of the object to be fired in the tunnel furnace. In addition, a pair of burners are arranged on the facing surfaces perpendicular to the moving direction of the object to be burned, one of which is in the state of ejecting the combustion gas and the other of which is in the state of exhausting the combustion gas. A method for heating an object to be fired in a tunnel furnace, wherein the burning temperature of each burner is individually controlled according to the firing conditions to heat the object to be fired. 8. A method for cooling an object to be fired in a tunnel furnace, wherein the object to be fired passes from one inlet to the other outlet, wherein a predetermined interval is provided along a moving direction of the object to be fired in the tunnel furnace. In addition, a pair of burners are arranged on the surfaces facing each other perpendicular to the moving direction of the object to be burned so that when one is in the state of ejecting combustion gas, the other is in the state of exhausting combustion gas, and the heat flow in the furnace is set. Flow in the width direction of the furnace, the fuel supply to each burner arranged near the exit of the tunnel furnace is shut off, and only the air is supplied to form a cooling zone to cool the material to be fired. A method for cooling an object to be fired in a tunnel furnace characterized by the above. 9. Heating a material to be fired in a tunnel furnace in which the material to be fired moves from one inlet to the other outlet,
In the cooling method, when one is in a state of ejecting combustion gas, the other is provided at a predetermined interval along the moving direction of the burning object in the tunnel furnace, and the opposite surface is perpendicular to the moving direction of the burning object. The burners are arranged in pairs to exhaust the combustion gas, and the combustion temperature of each burner is individually controlled according to the firing conditions of the object to be fired to heat the object to be fired and the tunnel furnace An article to be fired in a tunnel furnace, characterized in that the supply of fuel to each burner arranged near the outlet is cut off, a cooling zone is formed by supplying only air, and the fired article is cooled. Heating and cooling methods.