WO2009093690A1

WO2009093690A1 - Sintering method for honeycomb compact

Info

Publication number: WO2009093690A1
Application number: PCT/JP2009/051079
Authority: WO
Inventors: Yukihisa Wada
Original assignee: Ngk Insulators, Ltd.
Priority date: 2008-01-24
Filing date: 2009-01-23
Publication date: 2009-07-30

Abstract

Provided is a method for sintering a ceramic honeycomb compact having many cells juxtaposed in the axial direction, by using a truck for a sintering furnace of a framework of a beam structure. The honeycomb compact sintering method for sintering a honeycomb compact, in which the framework (1) of the beam structure includes posts (3), bridge girder members (5a) bridged on the posts, and bridge girder members (5b) further bridged on the bridge girder members (5a), in which the bridge girder members (5b) bridged on the bridge girder members are so arranged as are spaced from the adjacent bridge girder members, and in which the honeycomb body is placed over the bridge girder members. Clearances are left between prism members so that the gases decomposed during the sintering operation can be prevented from leaving the bottom of the honeycomb compact thereby to suppress the defects such as cracks, which might otherwise be abruptly caused by a heat generation. The honeycomb compact can be reduced in size deformation thereby to improve the packing efficiency.

Description

Method for firing honeycomb formed body

The present invention relates to a method for firing a honeycomb formed body.

Conventionally, as a method for firing a honeycomb formed body, a firing furnace trolley made of a shelf assembly composed of support columns and shelf plates (hereinafter referred to as “conventional shelf assembly” as appropriate) is used, and shelves with four corners supported by support columns. A ceramic honeycomb formed body (hereinafter referred to as “fired object” as appropriate) was placed on the plate and fired.

For example, in the conventional shelf assembly shown in FIG. 4, the ceramic honeycomb molded body is fired by using a so-called multi-lag system shelf assembly that is generally composed of a column 101 and a plate-like (plate-like) shelf plate 103. I was going.

However, in a method of firing a honeycomb molded body using a conventional shelf assembly, that is, a firing furnace carriage composed of a support and a flat (plate-like) shelf board (hereinafter referred to as “conventional” In the case of firing a ceramic honeycomb formed body, there is no sufficient gap between the ceramic honeycomb formed body (fired object) and the shelf board, so that the fired body is fired during firing. The organic binder component contained in the product is thermally decomposed and gasified, and it is difficult for the decomposed gas generated inside to escape, and the temperature difference between the surface layer part and the inside of the molded body increases, resulting in a difference in the degreasing progress rate. As a result, distortion occurs in the molded body, and cracks occur. For this reason, it is common to degrease over time by lowering the rate of temperature rise, the production efficiency is poor, and a lot of energy is required for heating.

For example, when firing a ceramic honeycomb molded body using a conventional shelf assembly, as shown in FIG. 5, the support column 101 is provided with a mounting table 105 that supports the shelf plate 103 while mounting it, A shelf board 103 is placed on the mounting table 105. Further, the tochi 107 is placed on the shelf plate 103, and the honeycomb formed body 100 is placed on the aforementioned tochi 107. Thus, when a conventional shelf assembly is used, a sufficient gap is not formed between the ceramic honeycomb molded body and the shelf board (or between the ceramic honeycomb molded body and the shelf board via Tochi). As a result, the above-mentioned gas is accumulated in the object to be fired, and when the gas is fired at the time of firing, sudden heat generation occurs, and the temperature difference between the surface layer portion and the inside of the molded body increases, There has been a problem in that defects such as cracks occur.

Further, in the conventional firing method of the honeycomb formed body, since the area of the ground contact surface between the shelf board to be assembled and the bottom surface of the honeycomb formed body is large, the frictional resistance is reduced due to the shrinkage of the honeycomb formed body that occurs during firing. Therefore, there has been a problem that the honeycomb formed body has a variation in dimensions. For this reason, in order to suppress a dimensional deformation in the temperature range which a molded object raise | generates contraction, it heated over time with the temperature increase rate.

Furthermore, in the conventional method for firing a honeycomb formed body, since the four corners of the shelf board on which the object to be fired is placed are supported by the pillars, the distance between the pillars and the pillars is narrow. In such a case, the packing efficiency is low, the production efficiency is low, and the production cost is increased.

There are the following patent documents 1 to 3 for such various problems.

In patent document 1, it is a baking cart provided with the fire-resistant material shelf structure which can be used at the temperature of about 1300 degreeC or more in a ceramic industry, Comprising: A horizontal beam longitudinal beam is supported by the fire-resistant material shelf structure as needed. A firing cart in which a firing floor is provided on the beams is disclosed. Further, in Patent Document 2, the above-mentioned contents of Patent Document 1 are disclosed in the United Kingdom. However, in the refractory material shelf structure provided in these firing carts, in the firing cart, even if the strength of the firing cart is improved, the decomposition gas generated during firing of the honeycomb molded body is trapped in the honeycomb molded body. As a result, sudden heat generation occurs, causing defects such as cracks in the fired object, and by using the firing floor, the area of the ground contact surface with the bottom surface of the honeycomb molded body is large, and the friction resistance is increased. Dimensional deformation is likely to increase. Furthermore, since the four corners of the shelf board on which the object to be fired is placed are supported by the support columns, the packing efficiency is low, the production efficiency is low, and the production cost is likely to increase. Therefore, no specific solution has been taken for the aforementioned problem.

In Patent Document 3, a cart and a beam-structured shelf are disclosed on the cart, and the beam-structured shelf is composed of a triangular plate. This is insufficient for any of the above-mentioned problems.

As described above, the contents disclosed in any of the patent documents are not yet sufficient for solving the above-mentioned problems, and further improvements are required.

JP 59-197792 A British Patent Application Publication No. 2136100A U.S. Pat. No. 4,462,798

The present invention has been made to solve the above-described problems, and in a firing furnace carriage composed of a beam-structured shelf composed of columns and bridge members, a ceramic honeycomb formed body is placed on a prismatic member and fired. By doing so, since there is a gap between the prismatic member and the prismatic member, it is possible to suppress the decomposition gas generated inside the honeycomb molded body during firing from flowing out from the bottom of the honeycomb molded body, and abrupt heat generation. Further, it is possible to suppress the occurrence of defects such as cracks in the material to be fired. Further, when shrinking during firing, the dimensional deformation of the honeycomb formed body is reduced by reducing the frictional resistance, and the material to be fired has a large size. A method for firing a honeycomb formed body in which the packing efficiency is improved even in such a case.

According to the present invention, the following honeycomb molded body firing method is provided.

[1] A method of firing a ceramic honeycomb formed body having a large number of cells arranged in the axial direction by using a beam-structured shelf-fired bogie, wherein the beam-structured shelf includes a support, At least a bridge member to be bridged on a column, and a bridge member to be further bridged on the bridge member, the bridge member to be bridged on the bridge member is separated from an adjacent bridge member. A method for firing a honeycomb formed body, wherein the honeycomb formed body is placed and fired by placing the honeycomb body on the bridge member.

[2] The bridge member includes a first bridge member that is bridged on the support column and a second bridge member that is bridged on the first bridge member. The honeycomb structure according to [1], wherein the second bridge member is configured as a prism member formed of a rectangular column member, and the honeycomb body is placed on the second bridge member and fired. A method of firing the molded body.

[3] The method for firing the honeycomb formed body according to [2], wherein the first bridge member and the second bridge member are made of a composite material of silicon carbide and silicon nitride.

[4] The method for firing the honeycomb molded body according to [2] or [3], wherein a contact area between the second bridge member and a bottom surface of the honeycomb molded body is 20 to 70% of a bottom area of the honeycomb molded body.

[5] The fired honeycomb formed body according to any one of [2] to [4], wherein the second bridge members are arranged so that a distance between adjacent second bridge members is in a range of 10 to 150 mm. Method.

[6] The method for firing a honeycomb formed body according to any one of [2] to [5], wherein a torch is placed on the second bridge member, and the honeycomb formed body is placed and fired.

According to the present invention, since there is a gap between the prismatic member and the prismatic member, it is possible to prevent the decomposition gas generated inside the honeycomb molded body during firing from flowing out from the bottom of the honeycomb molded body and causing rapid heat generation. Moreover, it is possible to suppress the occurrence of defects such as cracks in the material to be fired.Furthermore, when shrinking during firing, the dimensional deformation of the honeycomb formed body is reduced by reducing the frictional resistance, and the material to be fired has a large size. Even if it becomes, the outstanding effect that the firing method of the honeycomb molded object which packing efficiency improves can be provided.

It is the figure which showed typically the shelf assembly in this embodiment, Comprising: It is a perspective view. It is the figure which showed typically the method of baking a ceramic honeycomb molded object using the shelf assembly in this embodiment. It is the figure which showed the honeycomb molded object typically. It is the perspective view which showed typically the conventional shelf assembly substantially comprised from a support | pillar and a flat plate (plate shape) shelf board. It is the figure which showed typically the method of baking a ceramic honeycomb molded object using the conventional shelf assembly.

Explanation of symbols

1: shelf assembly, 3: support column, 4: mounting table, 5: bridge member (5a: first bridging member, 5b: second bridging member), 7: reinforcing member, 10: central portion, 11: lower end portion, 13 : Gap, 100: honeycomb formed body, 101: support, 103: shelf board, 105: mounting table, 107: Tochi.

Hereinafter, the best mode for carrying out the method for firing a honeycomb formed body of the present invention will be specifically described. However, the present invention broadly includes a method for firing a honeycomb formed body having the invention-specific matters, and is not limited to the following embodiment.

[1] Configuration of firing method of honeycomb formed body of the present invention:
As shown in FIGS. 1 and 2, the method for firing a honeycomb formed body of the present invention is a ceramic having a large number of cells arranged in the axial direction using a beam-structured shelf firing furnace carriage (not shown). A method of firing a honeycomb formed body, in which a shelf 1 having a beam structure includes a column 3, a bridge member 5 to be bridged to the column 3, and a bridge member to be further bridged on the bridge member 5 5, the bridge member 5 to be bridged on the bridge member is disposed apart from the adjacent bridge member 5, and the honeycomb body 100 is placed on the bridge member 5 and fired. It is characterized by doing.

[1-1] Prop:
As shown in FIG. 1, the column 3 in this embodiment constitutes a part of the beam-structured shelf assembly 1 and is a support member in the vertical direction of the beam-structure shelf assembly. In the shelf structure of the beam structure, at least four support columns are fixed in a vertical direction and protruded from a support member disposed on a floor surface, a carriage top surface, or a car top. The number of struts is not limited to the above-mentioned number. For example, the size of the furnace and the honeycomb to be fired are as shown in FIG. A plurality of the molded bodies may be erected as required.

Examples of the material of the support include mullite, alumina, and silicon carbide. The column is also referred to as a bridge member 5 (also referred to as a “prism column member” or “beam”, hereinafter also referred to as a “prism column member” or “beam”), a load to be fired, and the like. It must be able to withstand high temperature firing. For this reason, it is preferable that the refractory material has high pressure resistance and high heat resistance.

More preferably, the support column is configured to contain silicon carbide and silicon nitride. A column formed containing silicon carbide and silicon nitride is preferable because it has high pressure resistance and excellent heat resistance.

Examples of the shape of the support include, but are not particularly limited to, a solid or hollow quadrangular or cylindrical support, a rectangular tube, and a prism.

In addition, since this support column is often provided with a plurality of through-holes for inserting and supporting a bridge member extending horizontally between the support columns, the shape of the through-holes may be elliptical or circular. preferable. Moreover, it is also one of the preferable forms that a mounting table is formed instead of the through hole and the bridging member is mounted.

Here, in the case of forming the mounting table in the present embodiment, not only the bridging member is simply mounted, but also the bridging member is mounted on the mounting table, and the bridging member is connected to the bridging member by a known fixing method or a known fixing tool. Fixing the mounting table is preferable because it can stably support a non-fired material such as a bridging member or a honeycomb.

In other words, a mounting table for bridging the bridge member that crosses the column may be formed, and the bridge member may be fixed on the mounting table by a known fixing method or fixed by a known fixing tool. Also good. It is more preferable to fix the mounting table than to mount the mounting table because the bridge member and the honeycomb body can be stably supported. By configuring the support in this way, it is possible to prevent cracks from occurring even when a load such as a fired body is applied via the bridge member and a stress such as twisting is applied to the support.

Further, when forming a through hole, the shape of the through hole is preferably, for example, elliptical or circular. In the case of forming a support column by combining the above mounting table and this through hole, for example, the surface of the through hole at the lower side of the support column is formed into a cylindrical surface, and a mounting table having a bottom surface shape substantially matching the cylindrical surface is provided. Then, the bridge member may be fixed in the through hole via the mounting table. If comprised in this way, since a support | pillar and a bridge member will contact in the whole cylindrical surface and can distribute and support a load, it is preferable.

1 and 2 show a support column 3 on which a mounting table 4 is specifically formed. Thus, it is preferable to form the mounting table 4 on the support column because the bridge member 5 can be easily mounted and the bridge can be easily bridged. Further, as described above, a known fixing method or fixture may be used in combination with the mounting table 4. When the bridge member 5 is fixed to the mounting table 4 through a known fixing method or a fixture, the bridge member, the honeycomb, and the like mounted on the mounting table can be stabilized, and a torsional stress or the like on the column This is preferable because the burden can be reduced and the strength of the column can be increased. FIG. 2 is a diagram schematically showing a method of firing a ceramic honeycomb formed body using the shelf assembly in the present embodiment.

When the column is hollow, the thickness of the column can be appropriately changed depending on the shape of the column, the weight of the object to be fired, the weight and dimensions of the shelf board to be used, etc., but usually 3 to 10 mm. The thickness is preferably about 3 to 5 mm.

In addition, an example of a method for manufacturing a support containing silicon carbide and silicon nitride will be described as a method for manufacturing the support. First, a predetermined amount of SiC powder, Si powder, a binder, water, or an organic solvent is kneaded and cast to obtain a molded body having a desired shape. Next, this molded body is dried at 90 ° C. and then fired in a nitrogen atmosphere to produce Si ₃ N ₄ by a reaction between Si and nitrogen, thereby producing a composite material of silicon carbide and silicon nitride. A method can be mentioned.

[1-2] Bridge members:
As shown in FIG. 1, the bridge member 5 in the present embodiment is a horizontal support member that constitutes a part of a beam-structured shelf assembly. There are bridge members that are used as members that are bridged to the columns and bridge members that are further used to bridge the bridge members that are bridged to the columns. The honeycomb formed body is placed on the latter bridge member and fired. Therefore, since the honeycomb formed body is placed on the bridge member in the beam-structured shelf, it is desirable that the bridge member is bridged in the horizontal direction. However, this horizontal direction does not require a horizontal state in a strict sense, and it is sufficient if the horizontal direction has a level enough to stably place the article to be fired.

It is desirable that the bridge member be arranged apart from the adjacent bridge member. This is because the adjacent bridge members are arranged without being separated from each other, so that no gas is trapped in the honeycomb structure, the contact area can be suppressed, and the effects of the present application can be achieved.

For example, as shown in FIG. 2, the column 3 is provided with a mounting table 4 that supports the bridge member 5 (first bridging member 5 a), and the bridge member 5 (second bridging member 5 b) on the mounting table 4. Is placed or fixed (via a fixture or the like). Further, the tochi 107 is placed on the bridge member 5 (second bridging member), and the honeycomb formed body 100 is placed on the tochi 107 described above. As described above, when the ceramic honeycomb formed body is fired by using the shelf assembly in the present embodiment, the ceramic honeycomb formed body 100 and the shelf board are connected between the ceramic honeycomb formed body 100 and the shelf board (or via Tochi. Gas) is not trapped in the fired product. Further, the contact area of the bottom surface of the honeycomb formed body is reduced, and the dimensional deformation of the honeycomb formed body can be controlled to be small by reducing the frictional resistance when shrinking during firing. Furthermore, the packing efficiency of the objects to be fired can be improved.

Here, “arranged apart from adjacent bridge members” means a relationship between a bridging member arranged on the same horizontal plane and a bridging member arranged on the same horizontal plane. “Disposed” means at least so as not to contact. This is because by arranging the bridging members arranged on the same horizontal plane so as not to contact each other at least, gas does not accumulate in the honeycomb structure and the effects of the present application can be achieved. In other words, the “adjacent bridge member” excludes a bridge member that is bridged by a column and a bridge member that is on the bridge member that is bridged by the column. This is because the bridging member that is bridged to the column and the bridging member that is on the bridge member bridged to the column are structurally in contact with each other and are not separated from each other.

It should be noted that the above-described horizontal plane does not require a horizontal plane state in a strict sense, and may be level enough to stably place the article to be fired.

For example, as shown in FIG. 2, the bridge member that is spaced apart from the “adjacent bridge member” is a relationship between the bridge member 5 b that is arranged on the same horizontal plane and the bridge member 5 b that is arranged on the same horizontal plane. The relationship between the bridging member 5a and the bridging member 5b is excluded.

In addition, the bridge member of the present embodiment is the same for both (1) the bridge member bridged to the column and (2) the bridge member further bridged to the bridge member bridged to the column. It can be composed of shape, material, etc. However, it is preferable that the bridge member is composed of a first bridge member that is bridged on a support column and a second bridge member that is bridged on the first bridge member, and the first bridge member is a flat plate member. The second bridge member is configured as a rectangular column member made of a rectangular column member, and the honeycomb body is placed on the second bridge member and fired. The first bridge member is used as a member to be bridged on the support column, and the second bridge member is used by being further bridged on the first bridge member. Then, the honeycomb formed body is placed on the second bridge member and fired. The reason why the bridging member is configured as a separate member in this manner is that it is easier to achieve the effects of the present application when the bridging member is made of a configuration and material corresponding to each role. Here, it is desirable that the first bridging member and the second bridging member are also bridged in the horizontal direction, but this horizontal direction does not require a horizontal state in a strict sense, and the product to be fired is stabilized. It is sufficient if there is a level of horizontalness.

[1-2-1] First bridge member:
As shown in FIG. 1, the first bridge member 5 a is a member for bridging the support column 3 and constitutes a part of the shelf assembly. Examples of the shape of the first bridge member 5a include a prismatic member having a prismatic shape, a flat plate member, and the like. However, a flat member is more preferable. When the first bridge member is composed of a flat plate member, a second bridge member described later can be easily placed on the first bridge member. This is because it is easy to place the components stably. However, the shape of the second bridge member is not limited to such a shape. For example, even if the second bridge member has a cylindrical shape, the surface on which the second bridge member or the like is to be placed is processed to be easily placed. Is included in the shape of the first bridge member in the present embodiment.

As the cross-sectional shape of the first bridge member, for example, a solid or hollow triangular columnar or quadrangular columnar column can be cited. It is because it can comprise as a lightweight member by shape | molding in a hollow etc. and can reduce the weight load to a support | pillar. Moreover, since the whole shelf assembly can be reduced in weight, there is convenience in moving it into the furnace.

It is desirable that the material of the first bridge member is composed of a refractory material having high compressive strength and high heat resistance. Examples thereof include silicon-impregnated silicon carbide refractories. By forming the first bridge member from such a member, it is possible to withstand the load of the body to be fired and the like, and to withstand high-temperature firing in the firing furnace.

Further, it is more preferable that the first bridge member is made of a composite material of silicon carbide and silicon nitride. When a prismatic member is formed from a composite material of silicon carbide and silicon nitride, it can further withstand the load of the object to be fired, and can withstand high-temperature firing in a firing furnace. To preferred.

In addition, as for the size of the first bridge member, the cross-sectional shape includes, for example, 120 × 20 mm / thickness 5 mm, 160 × 30 mm / thickness 5 mm, 200 × 50 mm / thickness 5 mm, etc., but is not limited to these sizes. If the structural strength of about 5 times the generated stress can be secured, there is no particular problem, and it can be used as a bridging member of the present application.

Further, the size of the first bridge member is not particularly limited, but a suitably wide one is preferable. This is because the second bridge member and the honeycomb formed body can be easily placed on the first bridge member and can be easily stabilized. For example, it is preferable to form the mounting table 4 as shown in FIG. Further, when the through-hole is formed and the second bridge member is penetrated, for example, when a fixing tool having a recess or the like corresponding to the diameter of the bridge member is used, rattling in the through-hole is reduced. Therefore, it is possible to use a prism member thinner than the through-hole diameter, which is preferable. It should be noted that it is desirable to select a suitable size for the first bridge member according to needs such as the weight of the honeycomb to be placed.

In addition, by using the first bridge member and the mounting base of the first bridge member or the mounting base and the fixture in combination, the column and the mounting base of the bridge member are in contact with each other over the entire surface. This is preferable because the load can be dispersed and supported. Moreover, even when a torsional stress is applied to the support column, the mounting table of the first bridge member rotates along the cylindrical surface to absorb the torsion, so that the support column can be prevented from being damaged by a crack.

As a method of attaching (assembling) the first bridge member to the support column, for example, the first bridge member is inserted into a through hole formed in the support column, and the first bridge member is mounted on the upper surface of the mounting table formed on the support column. It is preferable to mount and assemble (assemble) at least two first bridge members in parallel between the columns. If necessary, the first bridge member may be fixed to the upper surface of the mounting table by a known fixture or fixing method. Alternatively, a mounting base (a protruding portion of a support column) made of a columnar protrusion may be provided at a place where the first bridging member is placed, and a hole may be formed in the first bridging member to be inserted and fixed. A hole can be made in the first bridging member and the column, and a cylindrical pin can be inserted and fixed.

Furthermore, the second bridging member can be attached to the first bridging member by providing semicircular protrusions on both sides of the large bridging member to prevent the second bridging member from shifting. Moreover, a hole can be made in the first bridging member and the second bridging member, and a cylindrical pin can be inserted and fixed.

[1-2-2] Second bridge member:
As shown in FIG. 1, the second bridge member 5 b is a member for bridging on the first bridge members 5 a facing each other, and constitutes a part of the shelf assembly. The honeycomb formed body is placed on the second bridge member and fired. Examples of the shape of the second bridge member include a prismatic member having a prismatic shape, a flat plate member, and the like.

However, a prism member having a prismatic shape is more preferable. This is because, when the second bridge member is composed of a prismatic member, the surface on which the torch, the honeycomb formed body, etc. are placed is horizontal and easy to place stably. In addition, if it is not horizontal, the load applied to the honeycomb mounting surface is not uniform, and the honeycomb is likely to be deformed, or harmful effects such as cracks during firing are likely to occur, and the characteristics of the honeycomb are also impaired. Because. The above-mentioned horizontal does not require a horizontal state in a strict sense, and it is sufficient if the horizontality is sufficient to stably place a torch, a honeycomb formed body, and the like.

As the cross-sectional shape of the second bridge member, for example, a solid or hollow triangular columnar or quadrangular columnar column can be cited. It is because it can comprise as a lightweight member by shape | molding in a hollow etc. and can reduce the weight load to a support | pillar or a 1st bridge member. In addition, the weight of the entire shelf assembly can be reduced, which is convenient when moving into the furnace.

The material of the second bridge member is preferably composed of a refractory having high compressive strength and high heat resistance. For example, silicon-impregnated silicon carbide refractories can be used. By forming the first bridge member from such a member, it is possible to withstand the load of the body to be fired and the like, and to withstand high-temperature firing in the firing furnace.

It is more preferable that the second bridge member is made of a composite material of silicon carbide and silicon nitride. When a prismatic member is formed from a composite material of silicon carbide and silicon nitride, it can further withstand the load of the object to be fired, and can withstand high-temperature firing in a firing furnace. To preferred.

As the size of the second bridge member, for example, the cross-sectional shape of the bridge member may be 20 × 20 mm / thickness 5 mm, 30 × 30 mm / thickness 5 mm, 40 × 50 mm / thickness 5 mm, etc. There is no particular problem as long as a structural strength of about 5 times the generated stress can be ensured without being limited to a particular size, and it can be used as a bridging member of the present application.

As such a bridge member, for example, “nitride-bonded SiC” made by NGK Adrek or Saint-Gobain can be used.

Further, the size of the second bridge member is not particularly limited, but is preferably narrower than the size of the first bridge member but appropriately wide. If the width is too wide, the number of honeycomb molded bodies that can be mounted is reduced, and further, a gap between the second bridge member and the adjacent second bridge member cannot be formed, and gas tends to be trapped in the honeycomb molded body. This is because it becomes difficult to achieve the effects of the present application. Further, if the width is excessively narrow, it is difficult to stably place the honeycomb formed body. Further, the weight of the honeycomb formed body is locally concentrated on the contact surface with the second bridge member (or torch), and the like. This is because it may cause adverse effects. In addition, it is preferable to select a suitable size according to needs such as the weight of the honeycomb to be placed.

Further, in order to stably place the second bridge member, for example, when a fixture for the second bridge member having a recess corresponding to the diameter of the second bridge member is used, rattling is reduced. Can be mounted stably.

Further, the contact area between the second bridge member and the bottom surface of the honeycomb molded body is preferably 20 to 70% of the bottom area of the honeycomb molded body. It is preferable for the contact area to be within such a desired range because no gas is trapped in the honeycomb molded body, abnormal combustion of the molded body can be controlled, and the crack generation rate can be suppressed. That is, since the gap can be reliably formed between the second bridge member and the second bridge member, the effect of the present application can be achieved.

Furthermore, it is more preferable that the second bridge members are arranged so that the distance between adjacent second bridge members is in the range of 10 to 150 mm.

As a method for placing the second bridge member on the first bridge member, the second bridge member may be placed with a predetermined interval. For example, two or more prismatic members may be crossed and placed on the two members used as the first bridge member. However, it is desirable that the prism member used in (2) is placed so that an appropriate gap can be formed. This is because, if there is no gap, the honeycomb molded body is filled with gas, and the effects of the present application cannot be achieved. In addition, if the gap is large, the honeycomb formed body cannot be stably placed, and its own weight resulting from the inclination is concentrated locally, which may cause problems such as deformation of the honeycomb formed body.

[1-3] Beam structure shelf:
The shelf structure of the beam structure in the present embodiment includes at least the above-described support, a bridge member that is bridged to the support, and a bridge member that is further bridged on the bridge member. That is, a beam-structured shelf is configured by alternately stacking a pillar, a bridge member bridged by the pillar, and a bridge member further bridged on the bridge member.

For example, as shown in FIG. 1, as a beam-structured shelf structure, first, two columns × 2 columns = a total of four columns are erected, and the first bridge member is supported on the top of the column. The first bridge member is placed on the top of the column. In addition, you may arrange | position a reinforcement member as FIG. 1 shows as needed.

In addition, as shown in FIG. 1, a total of eight first bridge members 5a are arranged across the four levels in the length direction of the shelf assembly between the top of the column and the lowest part of the column. The second bridge member 5b is bridged and placed so as to bridge the pair of first bridge members 5a. In FIG. 1, the second bridge member 5b is mounted in a total of 24 pieces of 6 × 4 steps per step. Then, after placing the honeycomb formed body (or the honeycomb formed body through the torch) on the second bridge member that has been mounted, another column is set up at the four corners of the column in the same manner as described above. And the process of placing another first bridge member on the top of the column is repeated to complete the shelf assembly.

In addition, the member arrange | positioned at the top part of a support | pillar is not restricted to a 1st bridge member, If it can use as a beam and the durability which can respond to a calcination of a honeycomb is obtained, it will be 1st bridge. A widely known member may be used instead of the member.

Also, in this shelf structure, the number of columns used and the number of prism members used can be changed as appropriate depending on the shape of the shelf. In the shelf structure of the present invention, since the prismatic member containing silicon carbide and silicon nitride is used, the thickness of the prismatic member can be reduced. Specifically, the thickness can be reduced to about 25 to 50 cm × 25 to 50 cm × 5 mm (thickness). By being formed in this way, it is possible to reliably avoid the sticking between the support column and the shelf board, and it is possible to further improve the thermal efficiency and the firing efficiency.

[1-3-1] Platform for first bridge member:
A mounting base for the first bridge member, a fixture used in combination with the mounting base, etc. are not indispensable, but are preferably used because the first bridge member can be stably mounted and fixed. That is, the mounting member and the fixing member are in contact with the above-described prism member, support the load by dispersing, and the mounting table, the fixing tool, etc. become a so-called reinforcing member even when a torsional stress is applied to the column. It is possible to prevent damage to the support due to cracks.

The mounting table, the fixture used in combination with the mounting table, etc. may be configured separately from the column, and may be installed, for example, in an elliptical or circular through-hole formed in the column. Moreover, you may form in a support | pillar as integral. By being configured in this way, the mounting table, the fixture, etc. can be used as a support member for mounting the prism member on the upper surface thereof, and to play a role of buffering the torsional stress of the column.

[1-4] Tochi:
Tochi (Tochi) is a member to prevent defects and malfunctions such as chipping of the lower end outer periphery of the ceramic honeycomb that is a fired body, or cutting of the end face of the ceramic honeycomb, cracking of cells, rib cutting, etc. It is generally used and is preferably used also when firing the honeycomb formed body in the present embodiment. Here, tochi is also called a setter and refers to a so-called underlay-like member that supports the fired product on the cross-linking member. The tochi (tochi) is used between the honeycomb formed body and the first bridge member (square column member) when the honeycomb formed body is fired, and is configured as a plate-like member. The ceramic honeycomb structure is manufactured by firing a honeycomb formed body obtained by forming a green body in an upright state in a firing furnace with one end face down. During the firing, the honeycomb formed body contracts in the cell length direction and the direction orthogonal to the cell length direction, and if the honeycomb formed body is placed directly on the first bridge member, the first bridge is formed. Due to the frictional resistance between the member and the honeycomb formed body and the adhesion of the bridge member on the end face of the honeycomb formed body, the above-described adverse effects may occur. Therefore, in order to prevent such defects and defects, it is preferable to use Tochi (Tochi).

This tochi (tochi) is basically a sintered torch with no firing shrinkage, or an unfired torch with the same firing shrinkage made of the same material as the material to be fired. A certain “raw tochi / co-tochi” is common, but a tochi (tochi) suitably used in the present embodiment is “raw tochi / co-tochi”. Costs since the torch can be used repeatedly if “baked tochi” is used instead of unfired “raw tochi / co-tochi” made of the same material as the material to be fired and having the same firing shrinkage. However, since the “baked torch” becomes a so-called lid when the honeycomb formed body is fired, the gas generated from the binder cannot be completely removed and may be trapped in the honeycomb. Accordingly, since the effect of the present application cannot be sufficiently achieved, it is preferable to use “raw tochi / co-tochi”.

If this raw torch / co-torch is used, the cost can be increased because it can be used only once, but the occurrence of ribs, cells, etc. in the ceramic honeycomb is suppressed, so that the quality can be improved. Further, since the material is made of the same material as the honeycomb, the contact surface does not become a so-called lid of the honeycomb, and gas can be prevented from being trapped in the honeycomb.

It should be noted that not only the above-mentioned “raw torch / co-torch” but also “baked torch” is formed so that gas does not flow into the honeycomb molded body on its contact surface, for example, mounting As long as the contact surface of the honeycomb formed body is formed so as not to be damaged, it can be used as a torch in the present embodiment. However, it is preferable to use the “raw tochi / co-tochi” described above.

[1-5] Cart for firing furnace:
The calcination furnace trolley in the present embodiment is a pedestal (trolley) used by placing a honeycomb formed body, which is a product to be fired, on a beam-structured shelf on the calcination furnace trolley and moving the kiln in a predetermined direction. That is. The carriage for the firing furnace is formed so that a moving means can be attached. Needless to say, the present invention is not limited to such a baking table, and can be used as a baking table of the present application as long as it is a known baking table and can mount the beam structure of the present application.

[2] Ceramic honeycomb formed body:
The ceramic honeycomb formed body fired by the honeycomb formed body firing method of the present embodiment is a ceramic honeycomb formed body having a large number of cells arranged in the axial direction. The honeycomb formed body of the present embodiment is prepared by kneading a predetermined forming raw material to prepare a kneaded material, forming the prepared kneaded material to produce a honeycomb-shaped formed body, and drying it to form a honeycomb formed body Can be obtained by firing the honeycomb formed body obtained.

The method of kneading the forming raw material to prepare the kneaded material is not particularly limited, and examples thereof include a method using a kneader, a vacuum kneader or the like. The predetermined forming raw material can be appropriately selected according to a desired material.

The method for producing the honeycomb-shaped molded body is not particularly limited, and a conventionally known molding method such as extrusion molding, injection molding, or press molding can be used. Among them, a preferable example is a method of extruding the clay prepared as described above using a die having a desired outer peripheral wall thickness, partition wall thickness, and cell density. In order to manufacture the honeycomb structure of the present embodiment, it is necessary to form the outer peripheral wall thickness at a specific position thinner than other positions, and the method is as follows. In other words, the supply of soil to the place to be thinned is reduced by changing the diameter and arrangement of the back hole of the base and the shape of the press plate used to form the outer peripheral wall, thereby forming a specific position thinly. Make a difference in the outer wall thickness.

The drying method is not particularly limited, and conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, vacuum drying, vacuum drying, freeze drying and the like can be used. Especially, the drying method which combined hot air drying, microwave drying, or dielectric drying is preferable at the point which can dry the whole molded object rapidly and uniformly. The drying conditions can be appropriately selected according to the shape, material and the like of the honeycomb formed body.

The honeycomb formed body dried by the above-described method can be fired in a firing furnace to obtain the honeycomb structure of the present embodiment. The firing furnace and firing conditions can be appropriately selected according to the shape, material, and the like of the honeycomb formed body. Prior to firing, organic substances such as a binder may be burned and removed by temporary firing.

The material of the honeycomb formed body in the present embodiment is silicon-carbonized formed from silicon carbide (SiC), silicon carbide (SiC) as an aggregate and silicon (Si) as a binder from the viewpoint of strength and heat resistance. At least one selected from the group consisting of silicon-based composite materials, silicon nitride, cordierite, mullite, alumina, spinel, silicon carbide-cordierite-based composite materials, lithium aluminum silicate, aluminum titanate, and Fe-Cr-Al based metals The thing comprised from this can be mentioned. Among these, those composed of silicon carbide (SiC) or a silicon-silicon carbide based composite material are preferable.

When the plugs are formed in the cells of the honeycomb formed body in the present embodiment, the same material as the honeycomb formed body can be used as the filler used for the plugging. For plugging with a filler, for example, cells that are not plugged are masked, so that the end face of the honeycomb segment is immersed in a slurry-like filler and filled into open (unmasked) cells. This can be done. The filling of the filler may be performed before or after firing after forming the honeycomb, but it is preferable to perform the filling before firing because the firing step is completed once.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In the following Examples and Comparative Examples, “%” means parts by mass and mass% unless otherwise specified. Various evaluations and measurements in the examples were performed by the following methods.

[1] Experiment 1:
By setting the interval between the prismatic member and the prismatic member within a desired range, the temperature difference between the inside and outside of the molded body and the crack generation rate were measured.

Specifically, the temperature difference between the center portion and the lower end portion of the honeycomb molded body during burning of the organic binder was examined, and whether cracks were generated was examined visually or with a magnifying glass. Here, the temperature difference between the inside and outside of the formed body refers to a temperature difference during combustion of the organic binder between the center portion 10 and the lower end portion 11 of the honeycomb formed body as shown in FIG. FIG. 3 is a diagram schematically showing the honeycomb formed body, in which a large number of cells arranged in the axial direction are omitted.

[1-1] Preparation of honeycomb formed body (raw honeycomb structure) before firing:
As a raw material, cordierite-forming raw materials mainly composed of talc, kaolin, and alumina are mixed with water and binder, and then the mixed raw materials are extruded into a cylindrical shape by a kneader, and then extruded. Was extruded to obtain a raw honeycomb structure (honeycomb molded body) having a large number of cells of Φ320 mm × 300 mmL arranged in the axial direction.

[1-2] Production of beam-structured shelves in Examples 1 to 6:
Silicon carbide 75%, silicon nitride 25%, bulk specific gravity 2.5-3.0 g / cc, length 130 × width 70 (100 or 130) × total length 2000 mm (however, the values in parentheses above are (1) a column having a size of a mounting table (a size including a protruding portion of a column on which the first crosslinking member is mounted) for placing the crosslinking member, 75% silicon carbide, 25% silicon nitride, and a bulk specific gravity of 2.5 to 3 A first bridging member having a size of 0.0 g / cc and a length of 160 × width of 30 mm × length of 1500 mm and a diameter of 30 mm (length of 30 × width of 30 mm) × length of length of 1000 mm are prepared in advance, A four-tiered beam-structured shelf structure in which struts are arranged at four corners, two first bridging members are bridged on the struts, and the first bridging member is bridged with the second bridging member. Is shown in Table 1. Was set shelves are a second bridge member of Examples 1-6 so as to be the distance between the second cross member.

These columns and prism members are kneaded with a predetermined amount of SiC powder, Si powder, binder, water or organic solvent, and cast to obtain a molded body having a desired shape. Next, this molded body was dried at 90 ° C. and then fired in a nitrogen atmosphere to produce Si ₃ N ₄ by a reaction between Si and nitrogen, thereby producing a composite material of silicon carbide and silicon nitride. Is.

[1-3] Production of beam-structured shelf structure in Comparative Example 1:
Silicon carbide 75%, silicon nitride 25%, bulk specific gravity 2.5-3.0 g / cc, length 80 x width 60 (90, 120) x length 2000 mm (however, the figures in parentheses are the shelf boards) A column having a size of a mounting table (size including a protruding portion of the column on which the first bridging member is mounted), silicon carbide 75%, silicon nitride 25%, bulk specific gravity 2.5 to 3.0 g / A shelf board made of cc and having a size of 25 to 80 cm x 25 to 80 cm x 5 to 15 mm (thickness) is prepared in advance, the columns are arranged in 3 columns x 3 columns, and one shelf plate A four-tiered shelf assembly consisting of four bridges per unit was produced.

After drying the green honeycomb molded body, the green honeycomb structure was fired using the beam-structured shelf structures of Examples 1 to 6 and Comparative Example 1 to obtain a honeycomb fired body. The results are shown in Table 1.

[2] Experiment 2:
It was measured using calipers whether dimensional deformation occurred when the contact area between the prismatic member and the honeycomb formed body was within a desired range.

[2-1] Honeycomb compact (raw honeycomb structure):
The honeycomb formed body (raw honeycomb structure) before firing was prepared in the same manner as the honeycomb formed body (raw honeycomb structure) obtained in [1-1] above.

[2-2] Production of beam-structured shelves in Examples 7 to 11:
Silicon carbide 75%, silicon nitride 25%, bulk specific gravity 2.5-3.0 g / cc, length 130 × width 70 (100 or 130) × total length 2000 mm (however, the values in parentheses above are (1) a column having a size of a mounting table (a size including a protruding portion of a column on which the first crosslinking member is mounted) for placing the crosslinking member, 75% silicon carbide, 25% silicon nitride, and a bulk specific gravity of 2.5 to 3 A first bridging member having a size of 0.0 g / cc and a length of 160 × width of 30 mm × length of 1500 mm and a diameter of 30 mm (length of 30 × width of 30 mm) × length of length of 1000 mm are prepared in advance, A four-tiered beam-structured shelf structure in which struts are arranged at four corners, two first bridging members are bridged on the struts, and the first bridging member is bridged with the second bridging member. Is shown in Table 2. Is the Tanakumi so that the contact area between prism member and the honeycomb molded bodies of Examples 7-11.

In addition, the pillars and prismatic members of Examples 7 to 11 were molded in a desired shape by kneading and molding a predetermined amount of C powder, SiC powder, Si ₃ N ₄ , binder, water or organic solvent, as described above. After the body was obtained, the compact was prepared by placing the compact in an inert gas or vacuum under reduced pressure in a metal Si atmosphere and impregnating the compact with metal Si.

[2-3] Production of beam-structured shelf structure in Comparative Example 2:
The beam-structured shelf structure in Comparative Example 2 here is the same as the beam-structured shelf structure (shelf structure in Comparative Example 1) produced by the beam structure shelf structure of [1-3] described above. In Comparative Example 2, it means not the contact area between the prismatic member and the honeycomb formed body, but the contact area between the shelf board and the honeycomb formed body.

After the green honeycomb molded body is dried, the green honeycomb molded body is placed on the prismatic member so as to have a desired contact area using the beam structure shelves in Examples 7 to 11 and Comparative Example 2. Then, the fired honeycomb bodies of Examples 7 to 11 and Comparative Example 2 were obtained. The results are shown in Table 2. In Comparative Example 2, as described above, “the contact area between the prism and the honeycomb formed body” shown in Table 2 is read as “the contact area between the shelf board and the honeycomb formed body”.

(Discussion 1)
As shown in Table 1, the honeycomb formed body of Example 1 was obtained by forming a shelf with a spacing of 10 mm between the prisms and placing the honeycomb formed body on the shelf and firing it. . In the honeycomb molded body of Example 1, the temperature difference inside and outside the molded body was 65 ° C. and the crack generation rate was 1.5%, but this is not until the characteristics of the honeycomb molded body are greatly impaired. Results were obtained. The honeycomb molded bodies of Examples 2 to 6 were shelved with the intervals between the prisms being 30 mm, 60 mm, 90 mm, 120 mm, and 150 mm, respectively. As a result, the temperature difference between the inside and outside of the molded body of Example 2 was 54 ° C., the temperature difference between the inside and outside the molded body of Example 3 was 54 ° C., the temperature difference between the inside and outside of the molded body of Example 4 was 52 ° C. The difference is 48 ° C., the temperature difference between the inside and outside of the molded body of Example 6 is 48 ° C., the temperature difference between the inside and outside the molded body can be suppressed within a suitable range, and the occurrence rate of each crack is also 0%. It was.

On the other hand, in the honeycomb molded body of Comparative Example 1, since the shelf plate on which the honeycomb molded body is placed is a flat plate, there is no space between the prisms as shown in the above-described embodiments. Therefore, the temperature difference inside and outside the molded body was 95 ° C., and the crack generation rate was 3.2%, and it was proved as a result that it could not withstand the use that greatly deteriorated the characteristics of the honeycomb molded body.

(Discussion 2)
As shown in Table 2, in the honeycomb molded body of Example 7, the prismatic members are arranged and shelves so that the contact area between the prisms and the honeycomb molded body is 90%, and the honeycomb molded body is provided thereon. Was obtained by placing and firing. In the honeycomb formed body of Example 7, dimensional deformation occurred 1.0 mm, but this was not until the characteristics of the honeycomb formed body were greatly impaired, and a reasonable result was obtained. In addition, the honeycomb molded bodies of Examples 8 to 11 were arranged with shelves by placing prismatic members such that the contact area between the prisms and the honeycomb molded body was 70%, 50%, 30%, and 20%, A honeycomb formed body was placed thereon and fired. As a result, the dimensional deformation could be suppressed within a suitable range of 0.7 to 0.5 mm in all of Examples 8 to 11, and good results were obtained.

On the other hand, in the honeycomb molded body of Comparative Example 2, since the shelf plate on which the Nicam molded body is placed is a flat plate, the contact area between the prism and the honeycomb molded body as shown in each of the above embodiments cannot be adjusted. That is, in Comparative Example 1, the contact area between the shelf board and the honeycomb molded body is 100%, resulting in a dimensional deformation of 1.5 mm, which cannot be used to greatly impair the characteristics of the honeycomb molded body. It was proved as a result.

A method for firing a honeycomb formed body of the present invention is a method for firing a ceramic honeycomb formed body using a firing furnace carriage composed of a beam-structured shelf composed of columns and bridge members, the ceramic honeycomb formed body By placing and firing on the prismatic member, there is a gap between the prismatic member and the prismatic member, so the decomposition gas generated inside the honeycomb molded body during firing escapes from the bottom of the honeycomb molded body and suddenly Generation of defects such as cracks due to heat generation can be suppressed, dimensional deformation of the honeycomb formed body can be reduced, and the honeycomb formed body can be suitably used as a firing method for improving packing efficiency.

Claims

A method of firing a ceramic honeycomb formed body having a large number of cells arranged in the axial direction using a beam-structured shelf firing furnace carriage,
The beam structure shelf includes at least a support, a bridge member to be bridged to the support, and a bridge member to be further bridged on the bridge member,
The bridge member to be bridged on the bridge member is disposed apart from the adjacent bridge member,
A method for firing a honeycomb formed body, wherein the honeycomb body is placed on the bridge member and fired.
The bridge member is composed of a first bridge member bridged on the support column and a second bridge member bridged on the first bridge member,
The first bridge member is configured as a square member,
The second bridge member is configured as a prism member made of a prismatic column member,
The method for firing a honeycomb formed body according to claim 1, wherein the honeycomb body is placed on the second bridge member and fired.
The method for firing a honeycomb formed body according to claim 2, wherein the first bridge member and the second bridge member are made of a composite material of silicon carbide and silicon nitride.
The method for firing a honeycomb molded body according to claim 2 or 3, wherein a contact area between the second bridge member and a bottom surface of the honeycomb molded body is 20 to 70% of a bottom area of the honeycomb molded body.
The method for firing a honeycomb formed body according to any one of claims 2 to 4, wherein the second bridge members are arranged so that an interval between adjacent second bridge members is in a range of 10 to 150 mm.
The method for firing a honeycomb formed body according to any one of claims 2 to 5, wherein a torch is placed on the second bridge member, and the honeycomb formed body is placed and fired.