JP2859987B2 - Temperature control device for continuous firing furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous firing furnace for firing a product to be fired while being conveyed, and more particularly to a method for controlling the temperature in a continuous furnace such as a roller hearth kiln or a tunnel kiln.

[0002]

2. Description of the Related Art Conventionally, a roller hearth kiln for firing small and lightweight ceramic products such as tiles has a tunnel-shaped furnace body made of refractory bricks, ceramic fibers and the like. A large number of rollers for conveying the article to be fired are arranged side by side in the furnace length direction, and are rotationally driven by a driving device provided outside the casing. The inside of the furnace of the roller hearth kiln is heated by blowing a combustion gas by a burner or the like, and a gas flow is generated by a blower fan.

[0003]

However, according to the conventional roller hearth kiln, the heat curve from the furnace inlet to the furnace outlet indicates that the starting time of loading, the stopping time of loading, or the change in the weight of the firing target. It fluctuates greatly due to load fluctuation. In order to make the product to be fired uniform and of good quality, an appropriate heat curve such as A shown in FIG. 3, for example, is required. In the case of an overload, the temperature distribution in the furnace is as shown in FIG.

[0004] For example, at the time of initial startup of a furnace, in order to obtain a high-quality fired product, a dummy fired product used for applying a load to the furnace is inserted into the furnace, or a dummy fired product is removed. If not, firing of the fired product is performed after admitting the occurrence of defective products until the heat curve is stabilized. Such firing by the dummy or the occurrence of an initial defective product causes energy loss or product waste, and lowers production efficiency.

An object of the present invention is to provide a temperature control device for a continuous firing furnace capable of arbitrarily adjusting the temperature distribution in the furnace without being affected by load fluctuations.

[0006]

Means for Solving the Problems A temperature control apparatus for a continuous firing furnace according to the present invention for solving the above-mentioned problems includes a preheating zone,
In a continuous firing furnace comprising a firing zone and a cooling zone, a preheating zone having cooling air supply means for introducing cooling air and a furnace gas discharging means for discharging furnace gas, a heating means for introducing combustion gas, and cooling air And a cooling zone having a heating unit for introducing combustion gas, a cooling air supply unit for introducing cooling air, and a residual heat air recovery unit for recovering residual heat air. It is characterized by the following. The first, second, and third cooling air supply means;
The in-furnace gas discharge unit, the first and second heating units, and the residual heat air recovery unit are connected to the preheating zone, the firing zone, and the cooling zone.
By adjusting each region, temperature control can be performed for each region.

[0007]

According to the temperature control apparatus for a continuous firing furnace of the present invention, cooling air supply means, furnace gas discharge means, heating means and residual heat air recovery means are provided in the preheating zone, firing zone or cooling zone as described above. Therefore, it is possible to precisely control the temperature of each region, so that an appropriate heat curve is always maintained during operation of the furnace without receiving a load change.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. An embodiment in which the present invention is applied to a roller hearth kiln will be described. In a roller hearth kiln, a tunnel-shaped furnace body is housed in a casing formed of heat-resistant steel or the like. The furnace body is made of ceramic fiber, refractory brick, and the like. When one roller is viewed, a ceramic roller is bridged from one side wall of the furnace body to the other side wall. Many such rollers are arranged in parallel in the furnace length direction at predetermined intervals. One end of each roller is taken out of the side wall. A sprocket to which a driving force is transmitted by, for example, a chain is attached to an end of each of the extracted rollers.

For example, as shown in FIG. 1, a roller hearth kiln 1 includes a preheating zone 3, a first firing zone 4, a second
It comprises a sintering zone 5, a first cooling zone 6, a second cooling zone 7, a third cooling zone 8, and a furnace outlet 9, and the furnace length is, for example, several tens of meters. A cooling air supply port 12 is formed in the preheating region 3.
The cooling air supply port 12 supplies cooling air into the furnace through the control damper 13 by the cooling fan 14. A furnace gas outlet 15 is formed in the preheating zone 3, and a part of the furnace gas is discharged to the outside by an exhaust fan 16 via the furnace gas outlet 15.

In the first firing zone 4, a burner 17 is provided and a cooling air supply port 12 is formed. A burner 17 is provided in the second firing zone 5. In the first cooling zone 6, a burner 17 is provided, and a cooling air supply port 18 for introducing cooling air is formed. Cooling fan 22
Thus, cooling air is supplied into the furnace from the cooling air supply port 18 via the control damper 20. In the first cooling zone 6, a residual heat recovery port 24 for recovering residual heat air in the furnace is formed. The residual heat recovery fan 24
Thereby, the residual heat air in the furnace is discharged to the outside.

In the second cooling zone 7, a burner 17 is provided and a residual heat recovery port 24 is formed. Similarly, a part of the residual heat air is discharged from the residual heat recovery port 24 to the outside by the residual heat recovery fan 26. The third cooling zone 8 includes a cooling fan 3
0 to supply cooling air into the furnace.
Is formed.

The burner 17 controls the gas temperature in the furnace, and its output is controlled by an external signal. Further, the air volume of the cooling fans 14, 22, 30, the exhaust fan 16, and the residual heat recovery fan 26 is adjusted by an external signal. The opening of the control damper 13 and the control damper 20 is adjusted by an external signal. Next, the operation will be described.

In the preheating zone 3, when the load is large, the amount of cooling air supplied from the cooling air supply port 12 is reduced or stopped. This suppresses a temperature decrease in the furnace.
When the load is small, the control damper 13 or the cooling fan 14 is adjusted so as to increase the amount of cooling air supplied from the cooling air supply port 12. This suppresses a temperature rise in the furnace.

In the first firing zone 4, when the load is large, the amount of cooling air supplied from the cooling air supply port 12 is reduced, and the combustion amount of the burner 17 is increased. Conversely, when the load is small, the amount of cooling air is increased, and the amount of combustion of the burner 17 is reduced. In the second firing zone 5, the temperature inside the furnace is adjusted by the burner 17. In the first cooling zone 6, when the load is large, the amount of cooling air supplied from the cooling air supply port 18 is increased, and the combustion amount of the burner 17 is reduced. When the load is small, the amount of cooling air is reduced and the amount of combustion by the burner 17 is increased.

In the second cooling zone 7, the combustion amount of the burner 17 is reduced when the load is large, and the combustion amount by the burner 17 is increased when the load is small. In the third cooling zone 8, the temperature in the third cooling zone 8 is lowered by cooling air sent into the furnace from the cooling air supply port 28 by the cooling fan 30. Next, FIG. 4 shows a comparative example for comparing the embodiment shown in FIG. This comparative example 4 is different from the embodiment shown in FIG. 1 in the following point. The cooling air supply port 12 is not formed in the preheating area 3. The cooling air supply port 12 is not formed in the first firing area 4. The control damper 20 and the burner 17 are not provided in the first cooling area 6. The burner 17 is not provided in the second cooling area 7.

According to the configuration of this comparative example, since no cooling air supply device is provided in the preheating region, when the load in the preheating region is small or large, excessive rise or fall of the furnace temperature is suppressed. It is difficult. Further, a part of the cooling air into which the flow of the gas in the furnace is sent from the cooling air supply port 28 is recovered from the residual heat residual heat recovery port 24 by the residual heat recovery fan 26, but the remaining air flows to the upstream side. For this reason, precise control of the temperature in the cooling zone and the firing zone becomes difficult.

On the other hand, according to the above-described embodiment, since the temperature control is performed for each area, the heat curve due to the load fluctuation is changed to an appropriate heat curve such as A shown in FIGS. Regardless, it can be controlled precisely. For example, when a product to be fired having a large weight or the like is introduced from the furnace inlet 2, the load becomes large. In such a case, the control damper 13 is closed and the cooling air from the cooling air supply port 12 is supplied into the furnace. Stop introduction to. Conversely, for example, when a light weight product to be fired is introduced from the furnace inlet 2, the temperature is likely to rise excessively, so that the opening degree of the control damper 13 is increased and the supply of the cooling air from the cooling air supply port 12 Increase the amount and control to draw an appropriate heat curve.

As described above, according to the above embodiment, since the temperature can be controlled for each region, the heat curve due to the load variation can always be maintained at an appropriate heat curve. There is an effect that can be.

[0019]

As described above, the temperature control device for a continuous firing furnace according to the present invention has an effect that the heat curve can be arbitrarily adjusted. In particular, when the loading of the article to be fired is started or stopped, or when there is a load change such as weight, the heat curve in the furnace can always be maintained without being affected by these load changes. Thus, there is an effect that a high-quality article to be fired can be uniformly produced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a roller hearth kiln according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an example of an appropriate heat curve of a roller hearth kiln according to an embodiment of the present invention.

FIG. 3 is a characteristic diagram showing an example of a heat curve by a conventional roller hearth kiln.

FIG. 4 is a schematic configuration diagram illustrating a roller hearth kiln according to a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roller hearth kiln 3 Preheating area 4 First sintering area (sintering area) 5 Second sintering area (sintering area) 6 First cooling area (cooling area) 7 Second cooling area (cooling area) 8 Third cooling area (cooling) 12) Cooling air supply port (cooling air supply means) 15 Furnace gas discharge port (furnace gas discharging means) 17 Burner (heating means) 18 Cooling air supply port (cooling air supply means) 24 Residual heat air recovery port (residual heat) Air recovery means) 28 Cooling air supply port (Cooling air supply means)

Claims (1)

(57) [Claims] In a continuous firing furnace comprising a preheating zone, a firing zone and a cooling zone, a preheating zone having first cooling air supply means for introducing cooling air and furnace gas discharge means for discharging furnace gas is provided. A sintering zone having a first heating means for introducing a combustion gas and a second cooling air supply means for introducing a cooling air, a second heating means for introducing a combustion gas, and a third heating means for introducing a cooling air; A cooling zone having cooling air supply means and residual heat air recovery means for recovering residual heat air, wherein the first, second, and third cooling air supply means, the furnace gas discharge means, first and second Heating means, residual heat air recovery means for each area of the preheating zone, the firing zone and the cooling zone
A temperature control device for a continuous firing furnace, wherein the temperature is controlled for each of the regions by adjusting the temperature.