JPH0755347A - Burning furnace - Google Patents

Abstract

PURPOSE:To enable a stable control of an upper stage burner and a lower stage burner installed at a furnace wall to be carried out and a sufficient distribution of temperature within the furnace to be attained. CONSTITUTION:An upper stage burner 28 and a lower stage burner 29 are arranged at a furnace wall 22 within each of its zones. An output adjusting device 33 for the upper stage burner is arranged at a midway part of an air supplying passage 30 of the upper stage burner 28. An output adjusting device 41 for the lower stage burner is arranged at the midway part of an air supplying passage 36 of the lower stage burner 29. There is provided an adjusting meter 43 for controlling separately control motors 35 and 40 through each of positioners 44 and 45. The adjusting meter 43 controls the control motor 40 on the basis of a detected temperature of a temperature sensor 42 at a ceiling part of the zone and further controls the control motor 35 in such a manner that a heating output of the upper stage burner 28 becomes a predetermined rate in respect to a heating output of the lower stage burner 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a firing furnace in which a burner installed above and below a wall of a furnace heats a predetermined zone in the furnace to a set temperature.

[0002]

2. Description of the Related Art For example, in a firing furnace such as a tunnel furnace or a roller hearth kiln, the heating output of a burner is controlled so as to maintain a set temperature for each zone. Further, generally, in a high temperature zone (the latter half of the pre-tropical zone or the firing zone), burners are installed in two stages above and below the furnace wall. FIGS. 4 and 5 show a conventional example of a configuration for controlling each burner when the burners are installed in the upper and lower two stages.

That is, in the first conventional example shown in FIG. 4, the upper burner 2 and the lower burner 3 provided on the side wall of the tunnel-shaped furnace wall 1 are respectively provided in the combustion air supply passage. The dampers 4 and 5 control the amount of combustion air supplied. Gas is supplied to each of the burners 2 and 3 by a pressure equalizing valve 6 and 7 at a constant ratio with respect to the amount of combustion air supplied. Then, the temperature inside the furnace is detected by a temperature sensor 8 such as a thermocouple provided on the ceiling of the furnace wall 1 and is input to the temperature controller 9, and the temperature is detected based on the comparison result between the detected temperature and the set temperature. A control signal is output from the regulator 9,
Thus, the opening degrees of the dampers 4 and 5 are controlled.

Further, in the second conventional example shown in FIG. 5, the opening degree of each damper 4 and 5 is controlled by separate temperature controllers 10 and 11, of which the temperature for controlling the upper burner 2 is controlled. The controller 10 outputs a control signal based on the temperature detected by the upper temperature sensor 12 provided on the ceiling of the furnace wall 1, and the temperature controller 11 that controls the lower burner 3 is located in the middle of the furnace wall 1. A control signal is output based on the temperature detected by the lower temperature sensor 13 provided.

[0005]

However, the conventional configurations shown in FIGS. 4 and 5 have the following drawbacks, respectively. That is, first, in the case shown in FIG. 4, the same control is applied to the upper burner 2 and the lower burner 3, so that the upper part in the furnace has a higher temperature than necessary than the lower part. There is a problem that the lower part of the inside does not become sufficiently hot as compared with the upper part, and the temperature distribution state deteriorates.

On the other hand, in the case shown in FIG. 5, the temperature detected by the upper temperature sensor 12 is greatly affected by not only the combustion gas from the upper burner 2 but also the combustion gas from the lower burner 3. For example, the lower temperature sensor 13
When the heating output of the lower burner 3 is increased based on the detected temperature of the upper burner 3, the upper temperature sensor 12 detects a high temperature and the heating output of the upper burner 2 is lowered, and stable control is performed. There was a problem that was not done.

The present invention has been made in view of the above circumstances, and an object thereof is to install burners vertically on a furnace wall and to perform stable control of burners on the upper stage side and the lower stage side. It is an object of the present invention to provide a calcination furnace capable of achieving good temperature distribution in the furnace.

[0008]

The firing furnace of the present invention is one in which a predetermined zone in the furnace is heated to a set temperature by burners installed above and below the wall of the furnace. The output controller for the upper burner that adjusts the heating output of the burner, the output controller for the lower burner that adjusts the heating output of the lower burner, the temperature sensor that detects the temperature of the zone, and this temperature sensor A control signal is output to the output controller for the lower burner by comparing the detected temperature with the set temperature, and the heating output of the upper burner becomes a predetermined ratio with respect to the heating output of the lower burner. And a burner control means for outputting a control signal to the output controller for the upper burner.

Further, in this case, the burner control means may be configured so that the ratio of the heating output of the upper burner to the heating output of the lower burner can be freely changed.

[0010]

According to the above means, the burners on the upper side and the lower side are controlled based on the temperature detected by one of the temperature sensors. Therefore, different controls are applied to the burners on the upper side and the lower side. Is eliminated, and stable control can always be performed. And the burner on the upper side is
The heating output is controlled so that it has a predetermined ratio to the heating output of the lower burner.Therefore, by setting the ratio appropriately, the temperature distribution in the upper and lower parts of the furnace is as uniform as possible. can do.

Further, by making it possible to freely change the ratio of the heating output of the upper burner to the heating output of the lower burner, it is possible to execute finer control.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a tunnel furnace will be described below with reference to FIGS. FIG. 2 schematically shows an entire tunnel furnace 21 which is a firing furnace according to the present embodiment. The tunnel furnace 21 extends linearly in the front-rear direction by a furnace wall 22 (see FIG. 1) made of refractory material. It is configured like a tunnel.

As is well known, the inside of the tunnel furnace 21 is, in order from the inlet side (the right side in FIG. 2), the pre-tropical zone 23, the firing zone 24,
Cooling zone 25, of which pretropical zone 23 and firing zone 2
In FIG. 4, a plurality of burners for supplying combustion gas into the furnace 21 are installed on the left and right side wall portions (only the left side is shown) of the furnace wall 22, as will be described later. Figure 1
As shown in a part of FIG. 2, the article to be fired 26 such as tiles, tiles, sanitary ware, tableware, etc. is placed on the firing carriage 27 by a pillar (not shown) in a state where a fire duct is secured, and the firing truck 27 Is moved in the tunnel furnace 21 in sequence so that heating and firing are performed.

At this time, each part in the tunnel furnace 21 is
The temperature is maintained at a predetermined temperature suitable for firing of the article to be fired 26. Here, so-called zone control for controlling the temperature by dividing the furnace 21 into several zones in the traveling direction of the firing carriage 27 is performed. It is supposed to be done. In this case, as shown in FIG.
In the two zones A and B, the firing zone 24, C and D
2 zones are constructed.

A plurality of burners (for example, six burners on each side) are provided in each of the zones, and in the zones B, C, and D, where the temperature is relatively high, the burners 28 are arranged vertically in two stages. And 29 are installed. As shown in FIG. 1, the upper burner 2
Numeral 8 is provided on the upper portion of the side wall of the furnace wall 22 near the ceiling, and ejects combustion gas toward the portion between the article to be fired 26 and the ceiling portion.

On the other hand, the lower burner 29 is provided at a position slightly higher than the height of the firing carriage 27 on the furnace wall 22,
The combustion gas is ejected toward a portion between the firing carriage 27 and the article to be fired 26. The upper burner 28 has, for example, a rated output of 70,000 Kcal / hr.
As the lower burner 29, one having a larger rated output, for example, a rated output of 160,000 Kcal / hr is used.

The zones are controlled so as to be maintained at different set temperatures (temperatures increase in the order of A, B, C, D), but the zones are provided with upper and lower burners 28 and 29. In the above, the burners 28 and 29 are controlled by the configuration shown in FIG.

That is, the combustion air is supplied to the upper burner 28 from an air supply source (not shown) through the air supply passage 30, and the gas supply passage 3 is supplied from a gas supply source (not shown).
The gas is supplied through 1. A pressure equalizing valve 3 is provided between the air supply passage 30 and the gas supply passage 31.
2 is provided so that combustion air and gas are always supplied to the upper burner 28 at a constant ratio.

An output controller 33 for the upper stage burner for adjusting the supply amount of combustion air to the upper stage burner 28, and thus the heating output, is provided at an intermediate portion of the air supply passage 30 (upstream of the pressure equalizing valve 32). Has been. The upper burner output adjuster 33 includes a damper 34 located in the air supply passage 30, a control motor 35 for freely controlling the opening degree of the damper 34, and the like. In this case, one upper burner output controller 33 adjusts the heating output of all the upper burners 28 in one zone.

Similarly, regarding the lower burner 29, a pressure equalizing valve 38 is provided between the air supply passage 36 and the gas supply passage 37, and a damper 39 and a control motor 40 are provided in the middle of the air supply passage 36. An output controller 41 for the lower burner is provided. Again, one lower burner power regulator 41 regulates the heating power of all lower burners 29 in that zone.

On the other hand, on the ceiling of each zone, one temperature sensor 42, for example, a thermocouple, for detecting the temperature of the zone is provided. The detection signal of the temperature sensor 42 is input to the controller 43 with a proportional setting function. The controller 43 uses the electric positioner 4 based on the temperature detected by the temperature sensor 42.
The output controller 33 for the upper burner via 4 and 45
The control motor 35 and the lower burner output controller 41 (control motor 40) are controlled.

At this time, the controller 43 includes the temperature sensor 42.
The detected temperature of the lower burner 29 is compared with a preset temperature, and the control motor 40 for the lower burner 29 is controlled according to the comparison result, and at the same time, the heating output of the lower burner 29 is heated by the upper burner 28. The control motor 35 for the upper burner 28 is controlled so that the output becomes a predetermined ratio. In this case, the ratio can be set for each zone. Therefore, the controller 43 functions as the burner control means according to the present invention.

Next, the operation of the above configuration will be described. When performing the firing work, the operator sets the set temperature of each zone according to the type of the product to be fired 26, and the lower burner in each zone according to the stacking state of the product to be fired 26. The ratio of the heating output of the upper burner 28 to the heating output of 29 is set.

FIG. 3 shows an example of the set temperature and the ratio of the heating output of the upper burner 28 to the heating output of the lower burner 29 in the zones B, C and D. In FIG. 3, an example of the absolute value of the heating output is shown instead of the ratio, but this is the ratio as it is and B
The ratio is set to 4: 1 in the zone, 13: 4 in the C zone, and 7: 2 in the D zone.

When the burners 28 and 29 are operated and the firing work is started, the upper and lower burners 28 and 29 are controlled by the controller 43 in each zone. This control is performed when the detected temperature of the temperature sensor 42 is lower than the set temperature, the lower burner output controller 4
The opening degree of the damper 39 of No. 1 is increased to increase the heating output of the lower burner 29, and at the same time, the opening degree of the damper 34 of the output controller 33 for the upper burner is adjusted to obtain the heating output of the lower burner 29. On the other hand, the heating output of the upper burner 28 is set to a predetermined ratio (for example, 25% in the B zone). When the temperature detected by the temperature sensor 42 is higher than the set temperature, the heating output of the lower burner 29 is reduced, and the heating output of the upper burner 28 is set to a predetermined ratio with respect to the heating output of the lower burner 29.

Such upper and lower burners 28, 29
By controlling the temperature of each zone, the temperature of each zone can be maintained near the set temperature, and the firing carriage 27 is set in the tunnel furnace 21.
The object to be fired 26 is fired while being moved by. At this time, in each zone, the upper and lower burners 28 and 29 are controlled based on the temperature detected by one of the temperature sensors 42.
No different control is applied to 8 and 29, and stable control is always performed. And
The upper burner 28 is controlled so that the heating output always has a predetermined ratio with respect to the heating output of the lower burner 29, so that the upper and lower portions in the zone can have a temperature distribution as uniform as possible. .

As described above, according to this embodiment, the burners 28 and 29 installed in the upper and lower stages of each zone have a problem that stable control is not performed. Unlike the above, stable control of the upper and lower burners 28 and 29 can always be performed. Moreover,
Unlike the conventional example shown in FIG. 4 in which the temperature distribution in the furnace deteriorates, the temperature distribution in the furnace 21 (each zone) can be made good, and as a result, a uniform fired product can be stably obtained. Is what you can get.

In the above embodiment, the ratio of the heating output of the upper burner to the heating output of the lower burner is fixed, but the heating output of the lower burner is controlled by program control using, for example, a microcomputer. Alternatively, the ratio may be varied according to the temperature detected by the temperature sensor, and in this case, finer temperature control can be executed. Further, in the above embodiment, the so-called proportional control method is adopted in which the heating output is adjusted while keeping the ratio of the combustion air and the gas supplied to the burner constant. It is also possible to adopt a gas control system that adjusts.

In addition, a potentiometer or the above-mentioned microcomputer may be adopted as the burner control means, and the temperature sensor may be provided at the side wall of the furnace. Further, it is not limited to the tunnel furnace. For example, the present invention can be applied to all firing furnaces that perform zone control, and the present invention can be implemented with appropriate changes within the scope not departing from the gist.

[0030]

As is apparent from the above description, according to the firing furnace of the present invention, the burner installed above and below the furnace wall portion heats the predetermined zone in the furnace to the set temperature. The temperature sensor for detecting the temperature of the zone and the detected temperature of this temperature sensor are compared with the set temperature to output a control signal to the output controller for the lower burner and the heating output of the lower burner. In comparison with the burner control means for outputting a control signal to the output controller for the upper burner so that the heating output of the upper burner has a predetermined ratio, stable control of the upper and lower burners is provided. It has an excellent practical effect that the temperature distribution in the furnace can be improved and the temperature distribution in the furnace can be improved.

Further, in this case, if the burner control means is constituted so that the ratio of the heating output of the upper burner to the heating output of the lower burner can be freely changed, a finer control can be achieved. Is something that can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, showing a configuration for controlling a burner.

FIG. 2 is a diagram schematically showing the configuration of a tunnel furnace.

FIG. 3 is a diagram showing an example of set temperatures and burner heating outputs in each zone.

FIG. 4 is a diagram corresponding to FIG. 1 showing a first conventional example.

FIG. 5 is a view corresponding to FIG. 1 showing a second conventional example.

[Explanation of symbols]

Reference numeral 21 is a tunnel furnace (firing furnace), 22 is a furnace wall, 23 is a pre-tropical zone, 24 is a firing zone, 25 is a cooling zone, 26 is an article to be fired, 2
7 is a baking carriage, 28 is an upper burner, 29 is a lower burner, 33 is an output controller for the upper burner, 34 and 39 are dampers, 35 and 40 are control motors, 41 is an output controller for the lower burner, and 42 is a temperature sensor. , 43 are controllers (burner control means).

Claims (2)

[Claims] 1. A burner installed above and below the wall of a furnace to heat a predetermined zone in the furnace to a set temperature, wherein an output control for an upper burner for adjusting a heating output of the burner on the upper stage side. And an output controller for the lower burner that adjusts the heating output of the lower burner, a temperature sensor that detects the temperature of the zone, and the lower burner that compares the temperature detected by this temperature sensor with the set temperature. And a control signal to the output controller for the upper burner so that the heating output of the burner on the upper stage has a predetermined ratio to the heating output of the burner on the lower stage. And a burner control means for controlling the firing furnace. 2. The burner control means is configured to be able to freely change the ratio of the heating output of the upper burner to the heating output of the lower burner. The firing furnace described.