JP2008120653A - Placing table for firing ceramic honeycomb-formed body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently, uniformly degrease multiple ceramic honeycomb-formed bodies, to shorten the time required for firing and to reduce the cost of energy by improving the placing table for firing the honeycomb body. <P>SOLUTION: The placing faces 2 for placing the ceramic honeycomb-formed bodies 11 are composed by arranging a plurality of rod-like support members 21 in parallel. The placing face 2 has the openings 22 for air flowing between adjacent support members 21 to abut on the axial end faces of the formed bodies 11 to support them. A lightweight carriage 1 with good air permeability is prepared by stacking a plurality of the placing faces 2, fixing them by a fixing member 3 and providing the wheels 4 on the undersurface of the fixing member 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mounting table for mounting and supporting a ceramic honeycomb molded body when firing a ceramic honeycomb molded body applied to a ceramic filter, a ceramic carrier, or the like.

  Conventionally, a ceramic honeycomb structure made of cordierite or the like has been used as a filter base material for a particulate filter installed in an exhaust passage of a vehicle engine or a carrier for an exhaust gas purification catalyst. A ceramic honeycomb structure generally includes a honeycomb material having a large number of cells arranged in parallel in the axial direction by adding an auxiliary material such as an organic binder and water to a ceramic raw material and kneading the mixture, and extruding the obtained clay. It is manufactured by drying and firing a shaped product.

When firing a ceramic honeycomb formed body, a ceramic flat plate is usually used as a shelf board, and the ceramic honeycomb formed body is placed thereon. It arrange | positions in a baking furnace in this state, it heats, it heats up to predetermined baking temperature, and the sintered compact is obtained by hold | maintaining for predetermined time. When firing a plurality of ceramic honeycomb formed bodies at the same time, a plurality of shelf boards on which the formed bodies are mounted can be further stacked vertically to form a mounting table. Such a mounting table is described in Patent Documents 1 and 2, for example. Patent Document 3 describes a firing apparatus provided with a firing jig made of a container-like ceramic sheath filled with a molded body for small parts such as a plug insulator.
JP 2004-51469 A JP 2004-75458 A Japanese Patent Laid-Open No. 2000-100500

  FIG. 5A is a schematic view showing an example of a mounting table 100 used when simultaneously firing a large number of ceramic honeycomb formed bodies 11. The mounting table 100 has a configuration in which a plurality of flat shelf plates 101 are stacked in the vertical direction, and a plurality of ceramic honeycomb molded bodies 11 are mounted on the upper surface of each shelf plate 101 with the axial direction as the vertical direction. ing. The plurality of shelf boards 101 are connected to each other by columns 102 arranged at four corners.

  By the way, the organic auxiliary agent containing the binder is decomposed in the process of gradually raising the temperature of the molded body to the firing temperature and removed by burning (degreasing step). At this time, if the gas generated by decomposition or combustion does not diffuse quickly and stays in the cells of the ceramic honeycomb molded body, the temperature of the molded body becomes non-uniform, and cracks may occur due to stress due to the temperature difference. is there. In particular, on the bottom surface side of the ceramic honeycomb formed body, the cell opening is blocked by contact with the shelf board, and therefore, the degreasing gas is difficult to diffuse. For this reason, normally, the temperature increase rate in the degreasing process is reduced to suppress the temperature difference, which is a factor in increasing the firing time.

On the other hand, in the firing of small ceramics such as electronic parts, it is known to use a shelf plate having irregularities on the surface for the purpose of preventing deformation and contamination due to contact with the body to be fired. For example, in Patent Document 4, as shown in FIGS. 5B and 5C, firing setters 104 and 106 in which a plurality of V-shaped grooves 105 are formed in parallel in one direction or two directions on the mounting surface. Is described. Therefore, also in firing the ceramic honeycomb formed body, for example, a corrugated shelf plate provided with parallel grooves as shown in FIG. 5B is used to reduce the contact area, improve air permeability, and from the bottom side. It is possible to promote gas diffusion.
Japanese Patent Laid-Open No. 2004-250241

  However, by changing the shelf shape, gas diffusion from the bottom surface side becomes possible, but it cannot always be said that a sufficient effect is obtained. In order to ensure air permeability, it is better to increase the groove width and depth of the shelf board. However, since this lowers the strength of the shelf board, the upper limit of the groove width and depth is limited. by. On the other hand, in order to make the groove sufficiently large, it is only necessary to increase the thickness of the shelf, but not only the weight of the mounting table increases, but also the supplied heat is taken away by the shelf, so There is a problem that the fuel required for the increase increases and the energy cost increases.

  Moreover, as shown in FIG. 5A, when a plurality of shelf boards 101 are stacked and fired simultaneously, a plurality of ceramic honeycomb molded bodies 11 are fired simultaneously, the inside of the firing furnace is vertically moved by the plurality of shelf boards 101. Since it is divided, it is difficult for the entire firing furnace to have a uniform atmosphere. As a result, the atmosphere may vary depending on the position in the firing furnace, or a temperature difference is likely to occur, which may reduce the quality of the product.

  On the other hand, for example, in Patent Document 1, the microwave heating furnace is used and the mounting table is made of a specific material. However, it cannot be applied to a normal gas baking furnace or the like. Although it is possible to control the temperature by further providing convection / radiation heating means as in Patent Document 2, the configuration of the apparatus becomes complicated.

  Moreover, in patent document 3, the dispersion | variation in baking is reduced by filling a molded object in the box-shaped baking jig | tool, and baking it, conveying on a roller conveyor. However, this method is based on the premise that the firing jigs are not stacked but placed flat, and cannot be applied to a structure in which shelves are stacked. In particular, not only the weight of the mounting table increases but also the supplied heat is taken away by the shelf board, so the apparatus of the firing furnace is large, and the ceramic honeycomb molded body has a significantly reduced substrate strength due to the burning of the binder For this reason, it is difficult to fire while transporting.

  Therefore, normally, as shown in FIG. 5A, in order to improve the air permeability of the mounting table 100, the ceramic honeycomb molded bodies 11 are arranged on the shelf board 101 with a space therebetween, and also in the vertical direction. It is necessary to stack the shelves 101 with a sufficient interval. Furthermore, it is necessary to form a space 103 for ventilation between the mounting table 100 and the mounting table 100 so that the decomposition gas and the atmospheric gas can flow, and the space in the firing furnace should be fully utilized. I could not.

  In order to solve the above problems, the present invention improves a mounting table used when firing a ceramic honeycomb molded body, and can efficiently and uniformly degrease a large number of ceramic honeycomb molded bodies in a firing furnace. The purpose is to shorten the firing time, reduce the energy cost, and achieve both high quality and improved productivity.

  The invention of claim 1 for solving the above-mentioned problem is a mounting table for mounting and firing a ceramic honeycomb formed body having a large number of cells arranged in parallel in the axial direction, and a plurality of rod-shaped supports. A member, a mounting surface in which the plurality of supporting members are arranged in parallel, and a fixing member that holds each supporting member constituting the mounting surface. The mounting surface forms a ventilation gap between the adjacent support members, and allows the axial end surface of the ceramic honeycomb molded body to be fired to be abutted and supported by the upper surface of the support member. It is formed by arranging the plurality of support members at intervals.

  According to the said structure, the air permeability of a mounting surface can be improved significantly, supporting a ceramic honeycomb molded object. Therefore, the firing atmosphere can be made uniform, the degreasing gas can be diffused well, and the firing time can be shortened. And since it is lightweight, energy cost can be reduced significantly and high quality and productivity can be made compatible.

  In a second aspect of the invention, the plurality of support members have at least an upper surface in contact with the ceramic honeycomb formed body as a flat surface, a curved surface, or an uneven surface.

  If the contact surface is a flat surface, it can be stably supported. Alternatively, the contact area can be reduced by using a curved surface or an uneven surface.

  In the invention of claim 3, the plurality of support members have a substantially rectangular, substantially circular, substantially elliptical or substantially H-shaped cross-sectional shape, or a hollow shape.

  If it is substantially rectangular, the molded body can be supported stably. Further, when the shape is approximately circular, approximately elliptical, or approximately H-shaped, the contact area can be further reduced. By using a hollow shape, the weight can be further reduced.

  According to a fourth aspect of the present invention, there is provided a multi-layered structure in which a plurality of the mounting surfaces are stacked in the vertical direction.

  Since the mounting surface is lightweight, a laminated structure can be easily formed, and a large number of ceramic honeycomb formed bodies can be fired simultaneously.

  In invention of Claim 5, it has a some wheel which supports the said mounting surface so that a movement is possible.

  By setting it as the movable trolley | bogie structure, conveyance becomes easy and a degreasing process and a baking process can be performed continuously.

  As in the invention of claim 6, the plurality of support members may be made of ceramic. Preferably, when the plurality of support members are made of high-strength SiC as in the seventh aspect of the invention, the support members can be made thinner and the opening area can be made wider.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The firing mounting table of the present invention is for placing and firing a ceramic honeycomb formed body, has a light weight and good air permeability, and generates a uniform firing atmosphere and occurs in the ceramic honeycomb formed body. Allows good diffusion of degreasing gas. The ceramic honeycomb structure obtained by firing can be suitably used as a ceramic filter for collecting exhaust particulates, a ceramic carrier for exhaust gas purification catalyst, and the like.

  Fig.1 (a) is the schematic which shows the whole structure of the beam trolley | bogie 1 as a mounting base for baking to which this invention is applied, and FIG.1 (b)-(c) is the elements on larger scale. In FIG. 1A, the beam carriage 1 includes a plurality of mounting surfaces 2 on which the ceramic honeycomb molded body 11 is mounted, and a fixing member 3 that holds and fixes these mounting surfaces 2, and is provided on the fixing member 3. The plurality of wheels 4 are configured to be movable. The fixing member 3 rotatably holds the plurality of wheels 4 on the bottom surface of the base 31 and is mounted on the mounting surface 2 by four columns 32 (only two of which are shown in the figure) fixed to the top surface of the base 31. Holding. The ceramic honeycomb formed body 11 is transported into a firing furnace 5 to be described later in detail with reference to FIGS.

  As shown in FIGS. 1B to 1C, each mounting surface 2 is formed by arranging a plurality of rod-shaped support members 21 in parallel at equal intervals. Each support member 21 constituting the mounting surface 2 is made of a ceramic rod-like member (beam), and an opening 22 serving as a ventilation gap is formed between the support members 21. The ceramic honeycomb formed body 11 has a structure in which a large number of cells 12 are arranged in the axial direction inside a cylindrical outer cylinder, and one end surface (bottom surface in the figure) 13 where the large number of cells 12 open is a mounting surface. 2 is supported by contact. Here, for example, each ceramic honeycomb formed body 11 is disposed so as to be supported by a plurality of adjacent support members 21 with the opening 22 interposed therebetween. At this time, as shown in FIG. 1C, a large number of cells 12 of the ceramic honeycomb formed body 11 communicate with the outside (the firing furnace space) through the openings 22 formed between the adjacent support members 21. It becomes possible to ventilate.

  In the present embodiment, for example, an SiC (silicon carbide) beam having a substantially rectangular cross-sectional shape is used as the support member 21. Thus, when the support member 21 is rectangular, the contact surface with the ceramic honeycomb formed body 11 is a flat surface, and stable support is possible while ensuring air permeability. In addition, stability when the support member 21 is held by the fixing member is also improved. The material of the support member 21 is not particularly limited, but if high-strength SiC is used, the strength of the mounting surface 2 is improved, so that the size can be increased, or the support member 21 is made thin. There are advantages that the weight can be reduced and the air permeability can be improved by widening the opening 22. Other ceramic materials such as cordierite, mullite, and alumina may be used, and may be appropriately selected according to the type of the ceramic honeycomb formed body 11 and the like.

  The size of the mounting surface 2 of the beam carriage 1, the number of stacked layers, the interval between the plurality of support members 21 constituting the mounting surface 2 (that is, the size of the opening 22), and the like of the ceramic honeycomb molded body 11 to be mounted. It can be arbitrarily set according to the number and size, the size of the firing furnace 5, and the like. As shown in FIG. 3A, each mounting surface 2 is formed sufficiently large with respect to the ceramic honeycomb formed body 11 and has a plurality of support members 21 at intervals slightly smaller than the outer peripheral diameter of the ceramic honeycomb formed body 11. If the two are arranged in parallel, the two outer peripheral portions of the ceramic honeycomb formed body 11 can be stably supported by the two adjacent support members 21. Of course, the interval between the plurality of support members 21 may be made narrower, and the ceramic honeycomb formed body 11 may be supported by three or more support members 21.

  If the support member 21 is formed as thin as possible within a range where the strength can be maintained, the width of the opening 22 can be relatively widened. For example, when a SiC beam is used, the width of the upper surface of the support member 21 may be in the range of about 20 to 40 mm, the contact area with the ceramic honeycomb formed body 11 is reduced, and the cell is opened to the outside. It is possible to improve the escape of the degreasing gas. In addition, defective firing due to contact is less likely to occur. The ceramic honeycomb formed body 11 is appropriately arranged on the mounting surface 2 so that a space that allows ventilation is formed between adjacent ceramic honeycomb formed bodies 11. In the present invention, since the opening 22 of the mounting surface 2 is sufficiently large and has a sufficient space in the vertical direction, the ceramic honeycomb molded body 11 can be disposed relatively densely on the mounting surface 2. .

  As shown in FIG. 3B, the fixing member 3 that holds the placement surface 2 has a rod-shaped fixing portion 33 that extends in the width direction of the support member 21. The fixing portion 33 is installed between a pair of opposing support columns 32 (only one is shown in the figure), and supports one end of a plurality of support members 21 forming the mounting surface 2 on a flat upper surface thereof. ing. The other end of the support member 21 is also supported by a similar fixing portion (not shown). At this time, if a large number of linear protrusions are provided on the upper surface of the fixing portion 33 as shown in FIG. The linear protrusions that become the locking portions 34 are provided, for example, in the width direction of the fixing portion 33 at substantially the same interval as the width of the support member 21, and hold the support member 21 between a pair of adjacent locking portions 34. It is like that. If it does in this way, according to the magnitude | size of the ceramic honeycomb molded object 11, the latching position of the supporting member 21 can be changed easily and the magnitude | size of the opening part 22 can be adjusted.

  In addition, when it is desired to arbitrarily change the interval between the support members 21, it is not always necessary to provide the locking portion 34. Further, the shape and fixing method of the locking portion 34 are not limited to the illustrated configuration, and can be arbitrarily changed. The interval between the support members 21 is preferably, for example, 2/3 or less of the diameter of the ceramic honeycomb formed body 11 to be fired.

  In the present embodiment, the support member 21 has a substantially rectangular cross-sectional shape. However, the support member 21 may have an arbitrary shape such as a circle, an ellipse, a triangle, or a shape having irregularities on the surface. FIG. 4A shows the support member 21 having a hollow, substantially rectangular cross-sectional shape, and the weight can be further reduced by making the support member 21 hollow. Or as shown in FIG.4 (b), when it is set as substantially H cross-sectional shape, the area of the upper surface which contacts the ceramic honeycomb molded object 11 can be made smaller. As shown in FIG. 4C, when the hollow circular cross-sectional shape is adopted, the contact surface becomes a curved surface, and the contact area with the ceramic honeycomb formed body 11 can be reduced and the weight can be reduced. Also in these shapes, the size (width, height or diameter) of the support member 21 is preferably about 20 to 40 mm as described above. For example, FIG. 4A shows 25 × 20 mm (width × height). 4), FIG. 4B can be 25 × 35 mm (width × height), and FIG. 4C can be 25 mm (diameter).

The base ceramic of the ceramic honeycomb formed body 11 is not particularly limited, and various ceramic materials such as cordierite, alumina, silica, titania, silicon nitride, silicon carbide, oxides, nitrides, carbides, etc. Can be used. Preferably, when a cordierite (theoretical composition: 2MgO · 2Al ₂ O ₃ · 5SiO ₂ ) is mainly used, a filter or catalyst carrier having low thermal expansion and high thermal shock resistance can be obtained. As the cordierite raw material, aluminum hydroxide, silica, talc, kaolin, alumina or the like is used, and these cordierite-forming raw materials are blended in advance so as to have a cordierite composition to obtain a ceramic raw material powder.

  The ceramic honeycomb formed body 11 is obtained by blending a molding aid containing an organic binder and water in a predetermined ratio with the ceramic raw material powder, mixing, and kneading, using a known extrusion molding machine. It can be obtained by extrusion molding into a honeycomb shape. As the organic binder, for example, a commonly known material such as methyl cellulose can be used, and a pore former, a lubricant and other auxiliary agents may be appropriately added. The pore former is for controlling the porosity, pore diameter, etc. of the filter base material, and is burned away during the firing process of the ceramic honeycomb formed body 11, and the volume of the pores becomes pores.

  The ceramic honeycomb formed body 11 is further dried using a known dryer or the like, and then cut into a predetermined size and placed on the beam carriage 1 of the present invention shown in FIG. 1 and fired. . At this time, when the ceramic honeycomb formed body 11 is arranged on the mounting surface 2 via the ring-shaped setter 14 as shown in FIG. 1C, the ceramic honeycomb formed body 11 comes into direct contact with the support member 21. It is possible to avoid problems such as defective firing due to.

  FIGS. 2A and 2B show a firing furnace 5 having a tunnel furnace structure, and includes a transport unit 52 in which the beam carriage 1 is transported in a furnace body 51. In FIG. 2 (b), a gas burner 54 for heating is provided at the upper part of the conveying part 52, and a vent hole 53 is provided at the lower side surface so that the atmospheric gas circulates. 51 is forcibly exhausted by a blower 55 provided on the top surface of 51. An introduction pipe 56 for introducing outside air is provided at a position opposite to the gas burner 54. As shown in FIG. 2B, the beam carriage 1 is conveyed from the entrance 5a side of the firing furnace 5 toward the exit side while moving on a rail (not shown). The temperature in the firing furnace 5 is controlled using a temperature sensor or the like so that each part has a predetermined temperature, and the temperature is gradually increased at a predetermined temperature increase rate while passing through the illustrated degreasing process region. Thereafter, in the firing step region, the ceramic honeycomb structure is obtained by holding at a predetermined firing temperature for a predetermined time.

  Degreasing gas is generated in the ceramic honeycomb molded body 11 in this temperature raising step, particularly in a degreasing temperature region where organic substances such as an organic binder added to the ceramic honeycomb molded body 11 are decomposed and burned. In the present invention, since the mounting surface 2 of the beam carriage 1 on which the ceramic honeycomb molded body 11 is mounted has the large opening 22, this degreasing gas is diffused well and does not accumulate inside. Even in the structure in which the mounting surfaces 2 are stacked on the top and bottom, the air permeability is not impaired by the opening 22 of each mounting surface 2, so that the degreasing gas that has escaped to the outside is quickly exhausted. Is done. Therefore, the entire firing furnace 5 has a uniform atmosphere, and a large number of ceramic honeycomb molded bodies 11 can be efficiently and uniformly degreased. As a result, the firing time can be shortened, and the occurrence of firing defects due to temperature differences can be suppressed to reduce the energy cost.

Tables 1 and 2 use the conventional flat plate-like shelf plate or corrugated shelf plate for the generation ratio of firing failure (cracking) when the ceramic honeycomb formed body 11 is fired using the beam carriage 1. It is shown in comparison with the case where there was. Table 1 shows the case where the firing time is 55 hours, and Table 2 shows the case where the firing time is 72 hours. Moreover, the height in a table | surface is the height of the groove | channel of a corrugated sheet, and 0 mm in height is a flat shelf board. As is apparent from Table 1, when the firing time is short, a flat shelf or a corrugated shelf with a groove having a height lower than 8 mm has insufficient air permeability, and therefore a temperature difference. Due to this, cracks are likely to occur. Moreover, as shown in Table 2, it is possible to suppress cracks by increasing the firing time and taking time for degreasing, but the energy cost required for heating increases. On the other hand, in the present invention using the beam carriage 1, even if the firing time is shortened, cracks are not generated, and no energy is wasted for heating due to the light weight of the beam carriage 1, so that high quality and production are achieved. It is possible to achieve both improvement in property.

  Further, by using the beam carriage 1, the degreasing step and the firing step can be continuously performed while transporting the tunnel furnace as shown in FIG. 2, and the working efficiency is greatly improved. Furthermore, since the mounting surface 2 is configured using the lightweight support member 21, many ceramic honeycomb molded bodies 11 can be fired simultaneously by stacking the mounting surface 2. In addition, in the said embodiment, although the beam trolley | bogie 1 which laminated | stacked the mounting surface 2 was shown in two steps, it can also be set not only to this but three steps | paragraphs or more.

(A) is a schematic diagram of the entire configuration of a beam carriage, which is a mounting table for firing the ceramic honeycomb molded body of the present invention, (b) is a partially enlarged perspective view of (a) in an upper view of the mounting surface, and (c). FIG. 4 is a partially enlarged perspective view of FIG. (A), (b) is a schematic block diagram of the kiln used in the baking process of a ceramic honeycomb molded object. (A) is the elements on larger scale of the mounting surface of a beam trolley, (b) is the elements on larger scale for demonstrating the fixing member structure of a beam trolley. (A)-(c) is a figure which shows the other example of the cross-sectional shape of a supporting member. (A) is a figure which shows the conventional mounting base structure, (b) is a figure which shows the conventional shelf board structure.

Explanation of symbols

1 Beam cart (mounting table for firing)
DESCRIPTION OF SYMBOLS 11 Ceramic honeycomb molded body 12 Cell 2 Mounting surface 21 Support member 22 Opening part 3 Fixing member 31 Base | substrate 32 Support | pillar 4 Wheel 5 Firing furnace

Claims (7)

A mounting table for mounting and firing a ceramic honeycomb formed body having a large number of cells arranged in parallel in the axial direction,
A plurality of rod-shaped support members;
A mounting surface formed by arranging the plurality of support members in parallel;
A fixing member for holding and fixing each supporting member constituting the placement surface,
The mounting surface forms a ventilation gap between the adjacent support members, and allows the axial end surface of the ceramic honeycomb molded body to be fired to be abutted and supported by the upper surface of the support member. A firing stage for firing a ceramic honeycomb molded body, wherein the plurality of supporting members are arranged with intervals. The mounting table for firing a ceramic honeycomb molded body according to claim 1, wherein at least an upper surface of the plurality of supporting members that contacts the ceramic honeycomb molded body is a flat surface, a curved surface, or an uneven surface.   The mounting table for firing a ceramic honeycomb molded body according to claim 2, wherein the plurality of support members have a substantially rectangular, substantially circular, substantially elliptical or substantially H-shaped cross-sectional shape, or a hollow shape.   The mounting table for firing a ceramic honeycomb molded body according to any one of claims 1 to 3, wherein the mounting surface has a multilayer structure in which a plurality of the mounting surfaces are stacked at intervals in the vertical direction.   The mounting table for firing the ceramic honeycomb molded body according to any one of claims 1 to 4, further comprising a plurality of wheels that movably support the mounting surface.   The mounting table for firing a ceramic honeycomb molded body according to any one of claims 1 to 5, wherein the plurality of support members are made of ceramic.   The mounting table for firing a ceramic honeycomb molded body according to claim 6, wherein the plurality of support members are made of SiC.