JP2003075070A - Continuous calcination furnace, and manufacturing method for sintered product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous calcination furnace capable of arbitrarily setting a temperature profile in a calcination chamber, and a manufacturing method for a sintered product using the former furnace. SOLUTION: A vacancy 16 as a flow passage for a cooling medium is formed in a heat insulation layer 12b surrounding a calcination chamber 13 of a continuous calcination furnace so as to extend peripherally (direction perpendicular to a longitudinal furnace direction). A sintered product is manufactured by irradiating an article 15 to be sintered conveyed from a loading inlet to an extraction outlet in the calcination chamber 13 with microwaves to heat and sinter the sintered product 15 using the continuous calcination furnace.

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 continuously firing an article to be fired formed of a ceramic material, a fine ceramics material or the like, and a method for producing a fired body using the same.

[0002]

2. Description of the Related Art FIG. 6 (a) is a plan sectional view schematically showing a part of a continuous firing furnace previously proposed by the present inventors. In the continuous firing furnace, a portion of which is shown in the figure, microwaves are irradiated to the body to be fired 22 which is conveyed from the charging port to the extraction port in the firing chamber 21 to heat and fire the body to be fired 22. It is a thing. The firing chamber 21 is partitioned and formed in the furnace (inside the furnace wall 24) by a partition wall 23 including a heat insulating layer 23a having a heat insulating property and a microwave transmitting property.

The inventors of the present invention have made a partition 23 surrounding the firing chamber 21.
By varying the thickness of the heat insulating layer 23a in the furnace length direction, the temperature distribution in the furnace length direction (conveying direction of the object to be fired 22) in the firing chamber 21 can be set to an arbitrary pattern (for example, FIG. 6B).
It was found that it can be formed into a pattern as shown in FIG. In addition, the pattern of the temperature distribution in the furnace length direction in the firing chamber 21 can also be obtained by partially changing the material of the heat insulation layer 23a and making the heat insulation characteristics and the microwave absorption characteristics of the heat insulation layer 23a different in the furnace length direction. It has been found that (hereinafter, the pattern of the temperature distribution in the firing chamber 21 in the furnace length direction is referred to as a temperature profile in the firing chamber 21) can be arbitrarily formed.

According to such knowledge, the temperature profile in the firing chamber 21 can be arbitrarily set when designing the furnace, and therefore the temperature profile of the firing target 22 is set.
Can be easily optimized for firing.

[0005]

The object to be fired 2
If the materials, shapes, and sizes of the two differ, the temperature profile in the firing chamber 21 that is optimal for the firing also changes accordingly. For this reason, in order to fire various objects 22 to be fired in one continuous firing furnace, it is required that a temperature profile suitable for firing each object 22 can be formed in the firing chamber 21. However, in the above conventional continuous firing furnace,
Since the temperature profile in the firing chamber 21 is adjusted by making the thickness, the heat insulation property, or the microwave absorption property of the heat insulating layer 23a different in the furnace length direction, once the furnace is designed, the temperature profile in the firing chamber 21 can be changed. It is difficult to set it arbitrarily.

The present invention has been made by paying attention to the problems existing in the prior art as described above. An object of the invention is to provide a continuous firing furnace in which the temperature profile in the firing chamber can be arbitrarily set and a method for producing a fired body using the continuous firing furnace.

[0007]

In order to achieve the above object, the invention according to claim 1 has a firing chamber defined by a partition wall including a heat insulating layer having heat insulating property and microwave transmitting property. In the continuous firing furnace for irradiating the object to be fired conveyed from the charging port toward the extraction port in the baking chamber with microwaves to heat and fire the object to be fired, a channel of a cooling medium is provided in the heat insulating layer. The main point is to provide.

A second aspect of the present invention is characterized in that the object to be fired is fired by using the continuous firing furnace according to the first aspect to manufacture the fired body.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is embodied in a roller hearth type continuous firing furnace for firing an object to be fired formed of a ceramic material or a ceramic material will be described with reference to the drawings.

FIG. 1A is a sectional view (plane sectional view) in the furnace length direction schematically showing a part of the continuous firing furnace of this embodiment, and FIG. 2 is a sectional view taken along line 2-2 of FIG. 1A. It is a schematic diagram which shows. As shown in these figures, the continuous firing furnace is provided with a tunnel-shaped furnace wall 11 extending in a plane straight shape, and a cylindrical partition wall 12 extending in a plane straight shape along the furnace length direction inside the furnace wall 11. It is provided with a firing chamber 13 partitioned by. In this continuous calcination furnace, the furnace is continuously charged into the furnace through a charging port (not shown), and a roller conveyor (not shown; however, FIG. 2 shows the rollers 14 constituting the roller conveyor) is used to extract the extraction port (not shown). The inside of the furnace (inside the furnace wall 11) is output from a microwave oscillator (not shown) with respect to the object to be baked 15 that is conveyed in the baking chamber 13 in the direction (right side in FIG. Is irradiated with the microwave incident on the object to be fired 15, and the object to be fired 15 is heated and fired.

The inner surface of the furnace wall 11 is made of a material that reflects microwaves. Specific examples of the material that reflects the microwave include metals such as stainless steel.

The partition wall 12 has a two-layer structure comprising a heat generating layer 12a and a heat insulating layer 12b surrounding the heat generating layer 12a. The heat generating layer 12a is formed of a material that self-heats by microwaves. Specific examples of the material that self-heats by the microwave include a mullite material, a silicon nitride material, and alumina. On the other hand, the heat insulating layer 12b is formed of a material having a heat insulating property and a microwave transmitting property. Specific examples of the material having the heat insulating property and the microwave transmitting property include alumina fiber and foamed alumina.

As shown in FIG. 1A, the partition wall 12 has
A region A in which the thickness of the heat insulating layer 12b gradually increases toward the extraction port side, a region B in which the thickness of the heat insulating layer 12b is maximum and which is constant in the furnace length direction, and the thickness gradually decreases toward the extraction port side. The region C to be formed is in order along the conveyance direction of the body to be fired 15. Of these, in the heat insulating layer 12b in the regions A and C, the circumferential direction (direction orthogonal to the furnace length direction)
A large number of holes 16 (corresponding to the flow path of the cooling medium) extending to the are formed.

As shown in FIG. 2, each of the holes 16 is open at two locations, an upper side and a lower side, and pipes 17 and 18 are connected to the respective openings. The lower pipe 17 is connected via a valve (not shown) to a cylinder (not shown) in which compressed air is sealed, and the air in the cylinder (normal temperature air) is connected according to the opening of the valve. (Corresponding to the cooling medium) is introduced into the holes 16 via the pipe 17. Piping 17
The air introduced into the air holes 16 via the above flows through the air holes 16 toward the upper opening, and is led out of the furnace via the upper pipe 18.

The operation and effect obtained by this embodiment will be described below. Heating layer 12 by microwave
When a is self-heated and the temperature inside the firing chamber 13 is high,
Air (normal temperature air) is introduced from a cylinder into the holes 16 formed in the heat insulating layer 12b. Then, when the air introduced into the holes 16 exchanges heat with the heat generating layer 12a near the holes 16 when flowing through the holes 16, the air is fired in a limited region near the holes 16. The temperature inside the chamber 13 decreases. The degree of temperature decrease in the firing chamber 13 due to the air flowing through the holes 16 is adjusted by adjusting the amount of air introduced into the holes 16 (introduction speed) to change the heat exchange efficiency. Can be controlled. Therefore, according to the present embodiment, the temperature profile in the firing chamber 13 can be set arbitrarily by adjusting the amount of air (introduction speed) introduced into each hole 16 even in a furnace after design. You can Therefore, by optimizing the temperature profile in the firing chamber 13 according to the material, shape, and size of the body to be fired 15, it is possible to handle various firing of the body to be fired 15 in one continuous firing furnace. .

In the continuous firing furnace of this embodiment, when microwaves are made to enter the furnace without introducing air into the holes 16, the thickness of the heat insulating layer 12b is made different in the furnace length direction. A temperature distribution as shown by a solid line α in FIG. At this time, when air is introduced into the holes 16 in the regions A and C of the partition wall 12 from the cylinder at a predetermined speed, the temperature in the firing chamber 13 decreases in that region, and the two-dot chain line β in FIG. A temperature distribution as shown by is formed. Further, when the air introduction speed is increased, the temperature in the firing chamber 13 in that region further decreases, and a temperature distribution as shown by a chain double-dashed line β ′ in the figure is formed.

The above embodiment may be modified as follows. In the above embodiment, the present invention is embodied in the roller hearth type continuous firing furnace that conveys the body to be fired 15 by the roller conveyor, but the method of conveying the body to be fired 15 is not limited thereto. For example, it may be embodied as a trolley-type continuous firing furnace in which the article to be fired 15 is transported by a trolley.

Although the thickness of the heat insulating layer 12b is made different in the furnace length direction in the above embodiment, the thickness of the heat insulating layer 12b may be constant in the furnace length direction. In the above-described embodiment, the holes 16 are formed only in the heat insulating layer 12b at the portions corresponding to the regions A and C of the partition wall 12, but the holes 16 may be formed throughout the furnace length direction. . Further, even when the holes 16 are provided only in a limited part of the heat insulating layer 12b, the position thereof is not particularly limited to the aspect of the embodiment.

In the above-mentioned embodiment, each hole 16 is formed so as to make one round in the circumferential direction of the partition wall 12, but it does not necessarily have to make one round, and need not fill one round. As shown in FIG. 3, the heat insulating layer 12b is changed to a structure in which plate-shaped members are bonded together, and a groove is formed in the bonding surface of the plate-shaped member, and the groove is formed in the holes 16 of the above-described embodiment. The configuration may be changed so that it is used as the flow path of the cooling medium.

In the above-described embodiment, the holes 16 are formed so as to extend in the circumferential direction (direction orthogonal to the furnace length direction), but they may be formed so as to extend in the furnace length direction. In the case of this configuration, for example, as shown in FIGS. 4 (a) and 4 (b), the diameters of the holes 16 are made different stepwise or continuously (stepwise in the example shown in FIG. 4) in the furnace length direction. Partition wall 1 as shown in FIG.
2, the position of the hole 16 in the radial direction, that is, the hole 16
If the distance between the heating layer 12a and the heating layer 12a is made different in the furnace length direction, the temperature in the firing chamber 13 is made different in the furnace length direction even if the thickness of the heat insulating layer 12b is constant in the furnace length direction. You can

In the above embodiment, the present invention is embodied in a continuous firing furnace including a firing chamber 13 defined by a cylindrical partition wall 12 extending in a straight line in a plane, but a tube extending in a circular plane shape or a plane bow shape. It may be embodied in a continuous firing furnace provided with a firing chamber 13 partitioned by a partition wall 12.

In the above-described embodiment, air is introduced into the holes 16, but other gas may be introduced instead of air. Alternatively, cooling air (cooling gas) may be introduced into the holes 16 instead of room temperature air.

The holes 16 of the above embodiment may be omitted, and an air cooling jacket may be attached to the outside of the heat insulating layer 12b. In this case, the combination of the air cooling jacket and the heat insulating layer 12b corresponds to the "heat insulating layer" in claim 1.

The heat generating layer 12a may be omitted in the above embodiment. In this case, the air introduced into the holes 16 exchanges heat with the air inside the baking chamber 13 when flowing through the holes 16, so that the baking chamber is limited to a limited region near the holes 16. The temperature inside 13 drops. Therefore, it is possible to obtain substantially the same effect as that of the above embodiment.

Next, the technical idea which can be understood from the above embodiment will be described below. The continuous firing furnace according to claim 1, wherein the partition wall includes a heating layer that generates heat by microwaves. According to this structure, radiative cooling of the body to be fired at the time of firing can be suppressed, so that a thermal gradient can be prevented from being generated in the body to be fired by the radiative cooling.

The continuous firing furnace according to claim 1, wherein a plurality of the flow paths are provided, and each flow path extends substantially orthogonal to the furnace length direction. According to this structure, the temperature in the firing chamber can be made different in the furnace length direction by adjusting the amount (introduction speed) of the cooling medium introduced into each flow path.

The continuous firing furnace according to claim 1, wherein the thickness of the heat insulating layer is different in the furnace length direction.
According to this structure, the temperature profile in the firing chamber can be roughly set by the thickness of the heat insulating layer, and can be finely adjusted by the amount (introduction speed) of the cooling medium introduced into the flow path.

[0028]

Since the present invention is constructed as described above, it has the following effects. According to the invention described in claim 1, the temperature profile in the firing chamber can be arbitrarily set.

According to the second aspect of the present invention, by setting the temperature profile in the firing chamber of the continuous firing furnace to one suitable for firing the article to be fired, a fired article of high quality can be obtained.

[Brief description of drawings]

FIG. 1A is a plan sectional view schematically showing a part of a continuous firing furnace according to an embodiment, and FIG. 1B is a graph showing the relationship between the temperature in the firing chamber and the position in the furnace length direction.

FIG. 2 is a schematic diagram showing a cross section taken along line 2-2 of FIG.

FIG. 3 is a plan sectional view schematically showing a part of a continuous firing furnace according to another embodiment.

FIG. 4A is a plan sectional view schematically showing a part of a continuous firing furnace according to another embodiment, and FIG.
The end view in the 4b line.

FIG. 5 is a plan sectional view schematically showing a part of a continuous firing furnace according to another embodiment.

FIG. 6A is a plan sectional view schematically showing a part of a conventional continuous firing furnace, and FIG. 6B is a graph showing the relationship between the temperature in the firing chamber and the position in the furnace length direction.

[Explanation of symbols]

Reference numeral 12 ... Partition walls, 12b ... Thermal insulation layer, 13 ... Firing chamber, 15 ... Firing object, 16 ... Voids.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) F27D 11/12 F27D 11/12 H05B 6/64 H05B 6/64 D (72) Inventor Motoyasu Sato Shiki City, Gifu Prefecture 322-6 Ishimachi Ministry of Education, Culture, Sports, Science and Technology, Institute of Fusion Science (72) Inventor Sadaji Takayama 3-11 Hoshigadai, Tajimi City, Gifu Prefecture Masatoshi Mizuno, Inventor Masatoshi Mizuno Tajimi City, Gifu Prefecture 3-11 Hosigadai, Gifu Prefectural Ceramics Research Laboratory (72) Inventor Toshio Hirai 3-11 Hosigadai, Tajimi Gifu Prefectural Ceramics Research Laboratory (72) Inventor Futo Kato Tajimi Gifu 3-11, Hoshigadai, Ichi, Gifu Prefectural Ceramics Research Laboratory (72) Inventor Toru Ochiai 719, Terakawado, Mizunami-shi, Gifu Pref., Minami Kiln Co., Ltd. (72) Kazumi Kato Address 719 F term in Mino Ceramics Co., Ltd. (reference) 3K090 AA01 AB 13 EB25 4K050 AA04 BA07 CA05 CB01 CD07 4K051 AA03 AB03 HA06 HA08 4K063 AA06 AA12 BA04 BA05 CA01 EA01 EA02 FA82

Claims (2)

[Claims] 1. A body to be fired, which has a firing chamber partitioned by a partition wall including a heat insulating layer having heat insulating properties and microwave permeability, and which is conveyed from the charging port toward the extraction port in the baking chamber. A continuous firing furnace for irradiating microwaves to heat and fire the article to be fired, wherein a flow path for a cooling medium is provided in the heat insulating layer. 2. A method for producing a fired body, which comprises firing a body to be fired by using the continuous firing furnace according to claim 1.