JPH06273055A - Roller hearth furnace - Google Patents

Abstract

PURPOSE:To provide a roller hearth furnace which has excellent area productivity and can simply treat exhaust gas. CONSTITUTION:A roller hearth furnace comprises a pair of burning passages 3A, 3B horizontally formed to be aligned in upper and lower parts in a body 2 in such a manner that one ends of the passages 3A, 3B are opened at one end 2a of the body 2, material-to-be-burned conveying rotary roller groups 5A, 5B reverse in rotating directions between the passages and arranged in the passages 3A, 3B, and material-to-be-burned elevating mechanisms 22, 23 provided at inner ends of the passages 3A, 3B to receive and deliver a material 40 to be burned between the passages 3A and 3B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller hearth furnace which conveys an object to be fired by rotating a group of rollers arranged in a furnace body.

[0002]

2. Description of the Related Art Conventionally, a roller hearth furnace of this kind is known as shown in FIG. FIG. 4 is a plan view and a side view of a conventional roller hearth furnace. In this roller hearth furnace 100, a firing passage 102 is formed horizontally in a furnace body 101, and in the firing passage 102,
A rotary roller group 103 for transporting the material to be fired and a heater 104 are arranged. Further, the roller hearth furnace 100 includes a return device 106 that returns the transfer table 105 that has reached the outlet 102b of the transfer passage 102 to the inlet 102a of the transfer passage 102 again. The return device 106 includes a transfer passage outlet 102b and an inlet 10 outside the furnace body 101.
2a is connected to form a rotary roller group 107.

[0003]

By the way, the above-mentioned roller hearth furnace 100 has a problem that the occupied area is large and the area productivity is poor. That is, the roller hearth furnace 100 of this type is usually designed to perform three firing steps of degreasing, firing, and cooling on the object to be fired,
The firing passage 102 needs a length adapted to these steps, and it is difficult to shorten it. Further, the roller hearth furnace 100 is provided with a returning device 106 for endlessly carrying the carrier 105. The returning device 106 is arranged by connecting the inlets and outlets 102b and 102a of the carrier passage 102. Since the inlets / outlets 102b and 102a are provided on the opposite side surfaces of the furnace body 101, the return device 106 has to be provided side by side in the width direction of the furnace body 101. For this reason, the area occupied by the roller hearth furnace 100 is increased and the area productivity is deteriorated.

[0004] Further, a substance to be fired such as a ceramic body fired in the roller hearth furnace 100 generates degreasing gas during the degreasing process of the substance to be fired, but since such degreasing gas becomes a pollution source, it remains as it is. It cannot be released into the atmosphere in the form of. Therefore, an exhaust gas treatment device (not shown) is separately provided so that the degreased gas is burnt here and then released into the atmosphere. Therefore, there is a problem that the initial cost and the running cost increase due to the provision of such an exhaust gas treatment device. Furthermore, even if an exhaust gas treatment device is provided, the exhaust pipe that guides the exhaust gas from the furnace to the exhaust gas treatment device must pass through the outside air once, so that the exhaust gas is cooled while passing through the exhaust pipe. There is also a problem that it takes a lot of time to clean it because it solidifies and becomes tar and sticks inside the exhaust pipe.

Therefore, it is an object of the present invention to provide a roller hearth furnace which has good area productivity and can treat exhaust gas easily.

[0006]

In order to achieve such an object, according to the present invention, a pair of firing passages are formed horizontally in the furnace body and arranged vertically above each other, and one end of these firing passages is formed. A rotary roller group for transporting the material to be fired, which is opened on one side surface of the furnace body and whose rotation direction is reversed between the firing passages, is arranged in these firing passages. A roller hearth furnace was constructed by providing an object-to-be-baked lifting mechanism for transferring the object to be baked between the baking passages at the inner end. Incidentally, an exhaust gas discharge pipe is arranged in the furnace body, the suction port of the exhaust gas discharge pipe is opened in a low temperature heating zone provided in one firing passage, and the discharge port of the exhaust gas discharge pipe is opened outside the furnace, In addition, it is preferable that the middle part of the exhaust gas discharge pipe is passed near the high temperature heating zone provided in the other burning passage.

[0007]

According to the above construction, since the firing passages are vertically stacked, the length of the furnace is half that of the conventional one.

Further, the material to be fired carried from one side surface of the furnace body into one of the firing passages is conveyed to the inner end of the firing passage, and then is moved to the inner end of the other firing passage by the elevating mechanism for the fired material. It is moved, and this time, it will be conveyed to the one side of the furnace body through the other burning passage. In this way, since the material to be fired is carried in from one side surface of the furnace body and is then carried out again from one side surface of the furnace body, the object to be fired in and the outlet is brought close to each other.

Further, when the exhaust gas exhaust pipe is arranged in the furnace body, the exhaust gas generated in the low temperature heating zone passes through the vicinity of the high temperature heating zone because the midway part of the exhaust gas exhaust pipe passes.
It will be burned while passing through here. Further, since the low-temperature heating zone and the high-temperature heating zone are arranged in a stack, they are close to each other, and the exhaust gas does not cool down while being conveyed from the low-temperature heating zone to the high-temperature heating zone.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a roller hearth furnace according to a first embodiment of the present invention.

This roller hearth furnace 1 is used for firing a material to be fired such as a ceramic body, and is provided with a furnace body 2 arranged in a horizontal orientation.
A pair of firing passages 3A and 3B are formed therein. The firing passages 3A and 3B are formed in the furnace body 2 horizontally and in parallel with each other. Further, one end of each of the firing passages 3A and 3B is opened to one side surface 2a of the furnace body 2, and inner ends thereof are connected to each other by a connection passage 4. That is, in the furnace body 2, the firing passages 3A and 3B connected in a U-shape are laterally arranged.

Each firing passage 3A. 3B is provided with rotating roller groups 5A and 5B for conveying the material to be fired and a heater 6 for heating the firing passage. The rollers 7 constituting the rotary roller groups 5A and 5B are rotationally driven in the same direction by a driving unit (not shown), but the rotation directions of the rollers 7 are opposite in the lower firing passage 3A and the upper firing passage 3B. There is. That is, the rotary roller group 5A of the lower firing passage 3A is driven to rotate counterclockwise in the figure, and the object to be fired placed on this rotary roller group 5A is discharged from the opening 8 of the lower firing passage 3A. It will be conveyed toward the inner end 9. On the other hand, the rotating roller group 5B in the upper baking passage 3B is rotationally driven in the clockwise direction, and the object to be baked placed on this rotating roller group 5B is opened from the inner end 10 of the upper baking passage 3B to the opening 1
It will be conveyed toward 1. In addition, the connection passage 4
Also, the upper and lower firing passages 3A. Heater 12 similar to 3B
And a rotating roller group 13 are arranged. The rotating roller group 13 is provided at the lower end of the connecting passage 4, and is continuously arranged at the same height as the rotating roller group 5A of the lower firing passage 3A. The rotary roller group 13 is rotatably driven by a drive unit (not shown) so as to be freely rotatable in the forward and reverse directions. Further, among the rotary roller group 5A of the lower firing passage 3A, the rotary roller group 5A ₁ located at the inner end 9 is set to have a higher rotation speed than the other rotary roller group 5A ₂ .

The heaters 6 and 12 are adapted to heat the inside of the firing passage for each heating zone provided along the firing passages 3A and 3B. That is, the opening 8 side of the lower firing passage 3A is in the low temperature heating zone (low temperature heating zone) A, the inner end 9 side of the lower firing passage 3B is in the temperature rising zone B, and the inner end 10 side of the upper firing passage 3B is in high temperature. The heaters 6 and 12 heat the inside of each of the firing passages 3A and 3B so that the heating zone (main firing zone) C is located on the side of the opening 11 of the upper firing passage 3B and the cooling zone D is located on the upper side.

The roller hearth furnace 1 is provided with an object-to-be-fired lifting mechanism 20. That is, the furnace body 2 includes a main body furnace body 21 in which the firing passages 3A and 3B are formed, and an end furnace body 22 in which the connecting passage 4 is formed. 22 is separably provided. The end furnace body 22 is attached so as to be vertically movable along the main furnace body 21 by an elevating part 23 such as an air cylinder. In addition, thick-walled portions 24 and 25 are formed at the upper end and the lower end of the end furnace body 22. These thick parts 24, 25
Is provided so that the firing passages 3A and 3B are not exposed to the outside of the furnace even when the end furnace body 22 is lifted by the elevating part 23. In addition, the end furnace body 22 has a sensor 2 for detecting an object to be fired.
6 is provided. The to-be-baked object detection sensor 26 detects that the to-be-baked object has reached the connecting passage 4 by contact with the to-be-baked object, and sends a to-be-baked object arrival signal to a control unit (not shown). In this embodiment, the end furnace body 22 and the elevating / lowering portion 23 constitute the baking target elevating / lowering mechanism 20.

On the other hand, a return device 30 is provided on one side surface 2a of the furnace body 2. The returning device 30 is the upper firing passage 3
When the material to be fired reaches the opening 11 which is the terminal end of the upper firing passage 3B after the conveyance in B is completed, the transfer table 105 on which the material to be fired is placed is opened again as the conveyance start end of the lower firing passage 3A. And a return table 31 disposed outside the opening 11 of the upper firing passage 3B, and the return table 3
1 is composed of an elevating part 32 that elevates and lowers between the upper firing passage 3B and the lower firing passage 3A. In addition, return platform 3
1 is provided with a rotation roller group 33 that can rotate normally and reversely, and a conveyance table detection sensor 34 that detects that the conveyance table 105 has arrived on the return table 31.

Next, firing of the object to be fired by the roller hearth furnace 1 will be described with reference to FIGS. 2 (a) and 2 (b). The article 40 to be fired placed on the carrier 105 is sequentially carried into the lower firing passage 3A from the opening 8. The article to be fired 40 carried in passes through the low temperature heating zone A provided in the lower firing passage 3A by being conveyed by the rotary roller group 5A, and is subjected to the firing process (degreasing process) in the previous step. The object 40 to be fired in the low temperature heating zone A in the previous step further passes through the temperature raising zone B, and then the inner end 9 of the lower firing passage 3A.
Reach The rotating roller group 5A ₁ provided at the inner end 9 of the lower baking passage 3A is rotating at a higher speed than the other rotating roller groups 5A ₂ , and the object to be baked 40 that has reached here is shown in FIG.
As shown in FIG. 3, the object 40 to be fired is separated from the rear article 40 to be carried into the connection passage 4. At this time, the rotating roller group 13 of the connecting passage 4 is rotationally driven in the same direction as the rotating roller group 5A of the lower baking passage 3A, so that the object 40 to be fired carried into the connecting passage 4 is surely fired. It is carried into the connection passage 4 until it comes into contact with the detection sensor 26.

When the article 40 to be baked is carried into the connecting passage 4, the article-to-be-baked detection sensor 26 detects the carrying-in of the article 40 to be baked and informs a control unit (not shown) of this fact. The control unit, which has been notified of the arrival of the to-be-baked object 40, temporarily stops the driving of the rotary roller group 13 in the connection passage 4, and
As shown in (b), the elevating part 23 is driven to burn the object 4 to be burned.
The end furnace body 22 is raised until 0 reaches the inner end 10 of the upper firing passage 3B. At this time, since the thickened portions 24 and 25 are formed in the end furnace body 22, the firing passage 3A,
3B is not exposed outside the furnace.

When the raising of the end furnace body 22 is completed, the rotating roller group 13 in the connecting passage 4 is reversely rotated, that is, rotated clockwise. Then, the article 40 to be fired is carried into the upper firing passage 3B. After carrying out the to-be-baked object 40 to the upper baking passage 3B, the end furnace body 22 is lowered to the original position by the elevating part 23, and the next to-be-baked object 40 is baked.
In preparation for loading into the connection passage 4. Here, the end furnace body 22
It is necessary to finish the transfer operation of the preceding baking object 40 and return to the original position by the time the next baking object 40 reaches the inner end 9 of the lower baking passage 3A. In this roller hearth furnace 1, the conveying speed of the rotating roller group 5A ₁ at the inner end 9 of the lower baking passage 3A is set to be higher than that of the other rotating roller group 5A ₂ so that the object 40 to be baked is moved backward. It is separated from the article to be fired 40, and the transfer of the article to be fired 40 has a time margin accordingly. Therefore, the end furnace body 22 can be surely returned to the original position by the time the article 40 to be fired at the rear reaches the inner end 9 of the lower firing passage 3A.

On the other hand, the object 40 to be fired carried into the upper baking passage 3B is conveyed to the opening 11 of the upper baking passage 3B by the rotating roller group 5B, while the high temperature heating zone C and the cooling zone D are being transferred. In this case, the firing process in the subsequent step is performed. The article 40 to be fired, which has been subjected to the firing process in the subsequent step, is conveyed to the opening 11 of the upper firing passage 3B, and the article 40 to be fired, which has been fired, is separated from the carrier 105 and is stored in another storage box or the like. Be transferred. Transport platform 1 with the object to be baked 40 separated
05 is further conveyed to the return table 31. At this time, the transport table 105 has the rotary roller group 33 of the return table 31 which is rotationally driven in the same direction as the rotary roller group 5B of the upper firing passage 3B.
As a result, the paper is conveyed on the return table 31 until it surely contacts the carriage detection sensor 34.

When the carrier 105 is loaded onto the return table 31, the carrier detection sensor 34 detects the loading of the carrier 105 and informs a control unit (not shown) of this fact. The control unit, which has been notified of the arrival of the transport table 105, temporarily stops the driving of the rotating roller group 33 of the return table 31 and causes the lifting unit 3
2 to drive the carrier 105 to open the opening 8 of the lower firing passage 3A.
The return table 31 is lowered until the temperature reaches. When the lowering of the return table 31 is completed, the rotating roller group 33 of the return table 31 is rotated in the reverse direction, that is, counterclockwise. Then, the carrier 105 is carried toward the inside of the lower firing passage 3A. After the carrier 105 is carried out into the lower baking passage 3A, the raising / lowering unit 32 raises the return table 31 to the original position to prepare for the arrival of the next carrier 105. In this manner, the carrier 105 is repeatedly used for the firing passages 3A, 3A.
B will be transported. Further, the firing in the roller hearth furnace 1 is performed by repeating the series of operations as described above.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a sectional view of the second embodiment of the present invention.
The basic structure of the roller hearth furnace 50 of this embodiment is the same as that of the first embodiment, and the same or similar parts are designated by the same reference numerals and detailed description thereof will be omitted.

The roller hearth furnace 50 is characterized by having an exhaust gas discharge pipe 51. That is, the exhaust gas discharge pipe 51 includes the suction pipe 52 arranged in the lower firing passage 3A and the incinerator pipe 5 arranged in the upper firing passage 3B.
3 and a connecting pipe 54 arranged in the furnace body 2 and connecting the suction pipe 5 and the incinerator pipe 52. An external lead-out pipe 55 is connected to the incinerator pipe 53, and the external lead-out pipe 5
The tip of 5 is led out of the furnace, and an exhaust fan 56 is attached to the tip. A plurality of suction pipes 52 are arranged in the ceiling portion from the low temperature heating zone A to the temperature rising zone B provided in the lower firing passage 3A.
An exhaust gas suction hole 57 is formed on the peripheral surface of the. The incinerator pipe 53 is a high temperature heating zone C provided in the upper firing passage 3B.
Is provided on the ceiling part of the, and fins 58 for enhancing heat conduction are formed on the peripheral surface thereof. In addition, a honeycomb 59 made of ceramic is arranged in a required place inside the incinerator pipe 53 in order to prolong the residence time of the exhaust gas. In addition to the honeycomb 59, for example, a metal net made of heat-resistant metal can be used for such a purpose. Furthermore, in the incinerator tube 53,
An incineration air supply pipe 60 is connected, and a tip of the incineration air supply pipe 60 is led out to the outside of the furnace, and a flow rate adjusting valve 61 is attached to the leading end.

Next, the firing process of the object 40 to be fired by the roller hearth furnace 50 will be described. The firing process of the roller hearth furnace 50 is basically the same as that of the roller hearth furnace 1 of the first embodiment. Therefore, the description will not be repeated. This roller hearth furnace 50 is characterized by processing exhaust gas during firing. That is, during the firing process, exhaust gas such as degreasing gas is generated from the article to be fired (ceramic body) 40 on the opening 8 side of the lower firing passage 3A which is the low temperature heating zone A. Such exhaust gas is exhausted by the exhaust fan 56.
After being sucked through the exhaust gas suction hole 57 provided in the suction pipe 52 by driving, the gas is introduced into the incineration pipe 53 through the connecting pipe 54. Exhaust gas such as degreasing gas is 80
Although it burns when it reaches a high temperature of about 0 to 1000 ° C., the temperature of the high temperature heating zone C provided with the incinerator pipe 53 is usually set to 1000 to 1300 ° C. when firing the ceramic body. Therefore, the exhaust gas introduced into the incinerator pipe 53 is combusted. Further, outside air is supplied to the inside of the incinerator pipe 53 through the incinerator air supply pipe 60, and further, since the honeycomb 59 is provided, the residence time of the exhaust gas in the incinerator pipe is long. Therefore, the exhaust gas is almost completely incinerated by sufficiently supplying the combustion air and prolonging the residence time of the exhaust gas in the incinerator. The supply amount of combustion air can be adjusted by opening / closing the flow rate adjusting valve 61 according to the incineration conditions. The exhaust gas that has been incinerated is discharged to the outside of the furnace through the external outlet pipe 55.

[0024]

As described above, according to the first aspect of the present invention, since the firing passages are stacked and arranged, the furnace length is halved, and the occupied area is reduced accordingly. In addition, since the loading / unloading port for the material to be fired is arranged on one side surface of the furnace body, the loading / unloading ports for the material to be fired are close to each other, and the return device disposed between them is downsized. I was able to do it. Therefore, the area occupied by the roller hearth furnace can be reduced to improve the area productivity.
Since the surface area of the roller hearth furnace is small, the amount of heat dissipated can be reduced, and the energy consumption can be reduced accordingly.

If the exhaust gas discharge pipe according to claim 2 is provided in the furnace body, the incineration treatment is performed by passing the exhaust gas generated in the low temperature heating zone outside the furnace in the vicinity of the high temperature heating zone. You will be able to do it. Therefore, it is not necessary to separately provide an exhaust gas treatment device to treat the exhaust gas, and the effect that the initial cost and running cost of the exhaust gas treatment device can be reduced accordingly is obtained.

Further, when the exhaust gas is treated by using the heat of the high temperature heating zone of the roller hearth furnace, the exhaust gas is cooled and tarted during transportation to the high temperature heating zone and sticks to a pipe or the like, which is troublesome to clean. However, in the case of the present invention, the high-temperature heating zone and the low-temperature heating zone are stacked and arranged close to each other due to the structure, so that there is an effect that the exhaust gas is cooled during transportation and hardly tarred.

In addition, since the heat in the firing passage is removed along with the combustion treatment of the exhaust gas, the cooling efficiency of the cooling zone provided adjacent to the high temperature heating zone can be enhanced.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a roller hearth furnace according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an operation during a firing step of the roller hearth furnace of the first embodiment.

FIG. 3 is a sectional view showing a structure of a roller hearth furnace according to a second embodiment of the present invention.

FIG. 4 is a plan view and a side view showing a structure of a conventional roller hearth furnace.

[Explanation of symbols]

 2 Furnace body 3A Lower firing path 3B Upper firing path 5A Lower rotation roller group 5B Upper rotation roller group 22 End furnace body 23 Lifting section A Low temperature heating zone C High temperature heating zone

Claims (2)

[Claims] 1. A pair of firing passages (3A, 3A) in a furnace body (2).
3B) are formed horizontally and vertically above each other, and one end of each of the firing passages (3A, 3B) is opened to one side surface (2a) of the furnace body (2), and these firing passages (3B) are formed. 3A, 3B) in the firing passage (3
A and 3B) are provided with a group of rotary rollers (5A, 5B) for conveying the material to be fired whose rotation directions are opposite to each other, and at the inner ends of these firing passages (3A, 3B), a firing passage (3A, 3B) is provided. Three
A roller hearth furnace provided with an object-to-be-baked lifting mechanism (22, 23) for transferring the object (40) to be baked between (A, 3B). 2. An exhaust gas discharge pipe (5) in the furnace body (2).
1) is provided, and the exhaust gas discharge pipe (51) has an inlet opening at a low temperature heating zone (A) provided in one firing passage (3A) and an outlet opening outside the furnace. The roller hearth furnace according to claim 1, characterized in that the middle part of the exhaust gas discharge pipe (51) is passed near the high temperature heating zone (C) provided in the other firing passage (3B). .