JP4528185B2 - Honeycomb structure extrusion molding equipment - Google Patents

Description

  The present invention relates to an apparatus for extrusion forming a honeycomb structure.

  A ceramic filter is a filter using a ceramic porous body, and is excellent in physical strength, durability, corrosion resistance, and the like. For example, in a wide range of fields such as water treatment, exhaust gas treatment, and pharmaceutical / food fields, It is used to remove suspended matter, bacteria, dust, etc.

  The porous body (honeycomb structure) used in the above ceramic filter is a kneaded material in which a dispersion medium, an organic binder, and a surfactant, a plasticizer, etc. are added if necessary in addition to an aggregate and a sintering aid. Can be obtained by extruding and drying, cutting it into a predetermined length perpendicular to the flow path direction, and firing it.

  Here, in the extrusion molding of the porous body (honeycomb structure), as shown in FIGS. 4 and 5, for example, as shown in FIGS. 4 and 5, a slit (discharge passage) of the die that contributes to the formation of the outer wall of the honeycomb structure at the time of extrusion molding. ) Among the spaces between the inclined surface 16 of the peripheral edge portion having the taper of the discharge portion 17 and the presser plate 12 facing the inclined surface, the innermost circumferential space is made narrower than the other spaces. That is, it is mainly performed to form a reservoir portion (outer peripheral inclined portion) 26 of the molding material in a space on the inclined surface 16 having a taper. As a result, the local pressure on the molding material (kneaded clay) in the space is relieved, and the honeycomb structure has a uniform outer wall thickness even when the outer wall thickness is within 5 times the cell wall and the cell wall thickness is thin. The body (porous body) can be easily formed without causing cell deformation in the outer peripheral portion (see Patent Document 1).

  In particular, in the case of a ceramic filter for water treatment, it is necessary to grind the outer wall of the honeycomb structure (porous body) in post-treatment, so that the outer wall thickness can be increased as much as possible without causing cell deformation. It was essential. If the outer wall thickness is too thin, the cell portion may be exposed by grinding to the outer wall in the peripheral grinding of the post-processing.

  In Patent Document 1, partial cells (non-standard cells existing at the boundary surface between the outer wall and the normal cell portion) or cells are formed on the outermost peripheral portion of the honeycomb structure (porous body) obtained after extrusion. There is a problem that cell defects such as deformation are likely to occur.

In particular, in the case of a ceramic filter for water treatment, a filtration membrane may be formed on the inner wall surface (that is, the support) of the main flow path of the honeycomb structure (porous body). When using a solid body (porous body), a honeycomb structure in which filtration membranes could not be formed (particularly at the interface between the outer wall and the cell part) or membrane defects occurred, while cell deformation occurred When a filter body (porous body) is used, after forming the filter membrane, the cell shape is distorted, resulting in a filter membrane defect such as a crack in the firing process that solidifies the filter membrane, and it does not function as a ceramic filter. There was a problem that the yield of the ceramic filter as a product was poor.
Japanese Patent No. 2925893

  The present invention has been made in view of such problems of the prior art, and its object is to form a membrane filter by preventing partial cells and cell deformation of a honeycomb structure having a thick outer wall. To provide a honeycomb structure extrusion molding apparatus that can contribute to the improvement of the yield and productivity of ceramic filters, which can prevent film defects such as defective film formation and cracks at the time. It is in.

  In order to achieve the above object, the present invention provides the following honeycomb structure extrusion molding apparatus.

[1] In addition to the base plate and the press plate that defines the outer wall of the honeycomb structure disposed on the outer peripheral side of the base, a back press plate that is also disposed on the outer peripheral side of the base and adjusts the amount of clay to be pushed out. A honeycomb structure extruding apparatus provided with a slit that discharges a cell structure in which the die is composed of thin walls connected to each other and an outer wall formed on the outermost peripheral side of the cell part. (Discharge passage) is opened at one end, and the other end is connected to a number of supply passages independently provided up to a certain depth, and a slit portion (discharge portion) having a slit (discharge passage) is a flat base. And an outer edge portion formed with an inclined surface inclined in the outer peripheral direction of the base portion, and the base portion constituting the slit disposed at the boundary between the base portion and the outer edge portion of the slit portion Before removing the material A back spacer having a thickness of 1.0 to 3.5 mm is inserted between the mouthpiece and the back presser plate, and the slit ratio of the slit of the base (the slit length / the slit width) is 7 As described above, for the honeycomb structure extrusion molding, the diameter of the outer edge portion is 1.2 times or less the diameter of the base portion, and the inner diameter of the backing plate is 1.0 to 1.1 times the diameter of the base portion. apparatus.

[2] the base member is removed, a honeycomb structure extrusion molding apparatus according to the counterbore portion formed is formed to be flat [1].

[ 3 ] The honeycomb structure extrusion molding apparatus according to [2], wherein a slit ratio (slit length / slit width) of a slit in the counterbore part is 0 to 6.

[ 4 ] The honeycomb structure extrusion molding device according to any one of [1] to [ 3 ], wherein an outer wall thickness ratio (minimum outer wall thickness / cell wall thickness) of the honeycomb structure is 1.3 or more.

  The honeycomb structure extrusion molding apparatus of the present invention prevents membrane defects such as film formation defects and cracks during filtration membrane formation by preventing partial cells and cell deformation of the honeycomb structure having a thick outer wall. Therefore, it is possible to contribute to the improvement of the yield and productivity of the ceramic filter as a product.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and may be appropriately selected based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that design changes, improvements, etc. may be made.

  FIG. 1 is a partial cross-sectional view showing the main part of the honeycomb structure extrusion molding apparatus of the present invention, FIG. 2 shows the main part of the honeycomb structure extrusion molding apparatus of the present invention, and (a) Sectional drawing of a principal part, (b) is a partially enlarged view of (a).

  The honeycomb structure extrusion molding apparatus according to the present invention includes, for example, a base 10 and a presser for defining an outer wall of the honeycomb structure disposed on the outer peripheral side of the base 10 as shown in FIGS. In addition to the plate 12, the honeycomb structure extruding apparatus is also provided with a back presser plate 15 that is disposed on the outer peripheral side of the base 10 and adjusts the amount of clay to be extruded. The base 10 has, at one end, slits (discharge passages) 17 and 18 for discharging a cell portion composed of thin walls connected to each other and a honeycomb structure having an outer wall formed on the outermost peripheral side of the cell portion. An end is connected to a number of supply passages 19 that are independently provided up to a certain depth, and a slit portion (discharge portion) 20 having slits (discharge passages) 17 and 18 is a flat base portion 21 and an outer periphery of the base portion 21 And an outer edge portion 22 on which an inclined surface 16 inclined in the direction is formed.

Here, as shown in FIGS. 1 and 2A, the main feature (1) of the honeycomb structure extrusion molding apparatus of the present invention is that the base 10 includes a base 21 and an outer edge portion 22 of the slit portion 20. is to remove the base member 2 5b constituting the slit 18 disposed at the boundary 24 of the. At this time, the inclined surface 16, after removing the base member 2 5b, so that the flat formed a counterbore portion 28 to form the outer edge 22 (see removal unit 29 of FIG. 2 (a)) that However, it is preferable for suppressing generation of partial cells during molding, supplying sufficient clay for forming the outer wall, and securing a target outer wall thickness. The counterbore part 28 is more preferably formed, for example, in the black paint part shown in FIG.

  Thereby, the honeycomb structure extrusion molding apparatus of the present invention exists in the cell outermost peripheral portion of the porous body (honeycomb structure) obtained after the extrusion molding, and is present at the boundary surface between the outer wall and the cell portion. Generation of non-standard cells) can be prevented.

  The main feature (2) of the honeycomb structure extrusion apparatus of the present invention is that a back spacer 14 is provided between a base 10 and a back presser plate 15 as shown in FIGS. 1 and 2A. Is to insert. At this time, it is preferable that the thickness t of the back spacer 14 used in the present invention is, for example, 1.0 to 3.5 mm (more preferably, 1.5 to 3.0 mm).

  As a result, the honeycomb structure extrusion molding apparatus of the present invention has a uniform outer wall thickness because the local pressure on the molding material (soil) in the space is relieved even when the outer wall thickness is increased. Can be easily formed without causing cell deformation on the outer peripheral portion thereof.

The honeycomb structure extrusion molding apparatus of the present invention has a slit ratio (slit length b ₁ / slit width a) of the slit 17 of the base portion 21 as shown in FIGS. 2 (a) and 2 (b). , 7 or more (more preferably, 8 to 15).

  This is because, when the slit ratio is smaller than 7, after the supplied clay is discharged from the slit portion, the pressure of the clay is low in the process of forming the cell wall of the molded body and This is because the pressure-bonding property is deteriorated and cracks are generated in the extruded molded body. On the other hand, when the slit ratio is more than 15, it is difficult to manufacture the die, and a sufficient effect cannot be obtained for the high cost.

In addition, as shown in FIG. 2 (b), the honeycomb structure extrusion molding apparatus of the present invention has a slit ratio (slit length b ₂ / slit width a) of the slit 18 of the counterbore portion 28 of 0 to 6. Preferably there is.

  This is because, when the slit ratio is larger than 6, the supplied clay is discharged from the slit portion and the outer wall of the molded body is formed in the process of forming the outer wall of the molded body. This is because the occurrence of (non-standard cells existing on the boundary surface between the outer wall and the cell portion) increases. Note that the slit ratio of 0 suggests that the counterbore part does not need to have a slit.

  Furthermore, in the honeycomb structure extrusion molding apparatus of the present invention, as shown in FIG. 1, the diameter C of the outer edge portion 22 is 1.20 times or less (more preferably 1.02-1) of the diameter A of the base portion 21. .15 times).

  This is because when the diameter C is smaller than 1.02 of the diameter A of the base portion, the supply amount of the clay for forming the outer wall cannot be secured, and the outer wall thickness becomes thin. On the other hand, when the diameter C is larger than 1.20 of the diameter A of the base portion, the amount of clay supplied at the outer peripheral portion is too large, and it is difficult to adjust the outer wall thickness by suppressing the deformation of the cells at the outer peripheral portion. It is.

  In the honeycomb structure extrusion molding apparatus of the present invention, as shown in FIG. 1, the inner diameter D of the backing plate is 1.00 to 1.10 times the diameter A of the base (more preferably 1.01 to 1.01). 1.05) is preferred. Specifically, when the diameter A of the base is 185.0 mm, the inner diameter D of the backing plate is preferably 185.0 to 203.5 (more preferably 186.9 to 194.3 mm). This is because when the inner diameter D of the backing plate is smaller than 1.00 times the diameter A of the base portion, the supply amount of the clay for forming the outer wall cannot be secured, the outer wall thickness becomes thinner, and the partial cell It will occur. On the other hand, when the inner diameter D of the backing plate is larger than 1.10 times the diameter A of the base portion, the amount of the clay supplied at the outer peripheral portion becomes too large, and the deformation of the cells at the outer peripheral portion is suppressed to reduce the outer wall thickness. It is difficult to adjust.

  From the above, the honeycomb structure extrusion molding apparatus of the present invention inserts the back spacer 14 between the base 10 and the back pressing plate 15 as shown in FIG. 1 and FIG. By setting the thickness t of the back spacer and the inner diameter D of the back retainer plate 15 from the center of the base 10 so as to satisfy the above conditions, the outer wall thickness ratio (minimum outer wall thickness can be obtained without generating a partial cell in the outer peripheral portion. / Cell wall thickness) can be 1.3 or more (more preferably, 2.0 to 4.0), and the cell deformation rate (inscribed circle of the maximum deformation cell among cells excluding partial cells) A honeycomb structure having a diameter conversion / converting the inscribed circle diameter of the average cell in the center 5 cell part) from 0.7 to 1.0 can be manufactured.

  In addition, when the honeycomb structure obtained in the present invention is used as a substrate for a ceramic filter for water treatment, it is excellent in film formation of a filtration membrane (especially at the interface between the outer wall and the cell portion). Moreover, since the film thickness of the filtration membrane is uniform and cracks can be significantly suppressed in the filtration membrane, the yield of the ceramic filter as a product can be greatly improved.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(Examples 1-20, Comparative Examples 1-8)
As the aggregate, alumina screened to have a particle size of 5 to 300 μm is used, and feldspar with a particle size of 0.5 to 5 μm is used as a sintering aid, water is used as a dispersion medium, and methylcellulose is used as an organic binder. The clay obtained by adding and kneading was extruded using a honeycomb structure extrusion molding apparatus having the conditions shown in Table 1 to obtain honeycomb shaped bodies having a plurality of main flow paths. After drying this molded body, it is cut perpendicularly to the flow path direction so as to have a predetermined length, and is fired to obtain an outer diameter of φ180 mm, an inscribed circle diameter of the flow path cell of φ2.5 mm, and a length of 1000 mm. A honeycomb-like porous body having about 2000 main channels was obtained. The average pore diameter of the porous body measured by the mercury intrusion method was 10 μm. Next, the number of cracked cells, the number of partial cells, the cell deformation rate, and the outer wall thickness ratio were measured for each of the obtained honeycomb structures. The results are shown in Table 1.

(Discussion: Examples 1 to 20 and Comparative Examples 1 to 8)
From the results of Table 1, in Examples 1 to 20, the dimensional ratio (C / A) is 1.01 to 1.2, the slit ratio is 7 to 15, and is arranged at the boundary between the base portion and the outer edge portion of the slit portion. has been removed to that base part member constituting the slits, to form a counterbore portion, using a back spacer, the thickness of the back spacer is 1.0～3.5Mm, and the dimensional ratio (D / a ) Is extruded under a condition of 1.01-1.10, so that cracks are not generated, partial cells are suppressed, and cell deformation is not caused. A structure was obtained.

On the other hand, in Comparative Example 1, since the slit ratio was less than 7, many cracks were generated in the obtained honeycomb structure. In Comparative Example 2, since the base portion member is not removed, a number of partial cells in the honeycomb structures obtained occurs. In Comparative Example 3 , since there was no back spacer, a large number of partial cells were generated in the obtained honeycomb structure. In Comparative Example 4 , since the thickness of the back spacer was less than 1.0 mm, a large number of partial cells were generated in the obtained honeycomb structure. In Comparative Example 5 , since the thickness of the back spacer exceeded 3.5 mm, cell deformation of the outer peripheral portion of the obtained honeycomb structure could not be sufficiently suppressed. In Comparative Example 6 , since the dimensional ratio (C / A) exceeded 1.2, cell deformation in the outer peripheral portion of the obtained honeycomb structure could not be sufficiently suppressed. In Comparative Example 7 , since the dimensional ratio (D / A) was less than 1.00, a large number of partial cells were generated in the obtained honeycomb structure. In Comparative Example 8 , since the dimensional ratio (D / A) exceeded 1.10, cell deformation in the outer peripheral portion of the obtained honeycomb structure could not be sufficiently suppressed.

  The honeycomb structure extrusion molding apparatus of the present invention is suitable for removing suspended substances, bacteria, dust, etc. in liquids and gases, for example, in a wide range of fields such as water treatment, exhaust gas treatment, and medicine / food. A honeycomb structure used for a ceramic filter that can be used can be preferably manufactured.

It is a fragmentary sectional view which shows the principal part of the apparatus for honeycomb structure extrusion molding of this invention. The main part of the apparatus for honeycomb structure extrusion molding of this invention is shown, (a) is principal part sectional drawing, (b) is the elements on larger scale of (a). FIG. 2 is a partially enlarged plan view of a die used in the honeycomb structure extrusion molding apparatus of the present invention. FIG. 6 is a partial cross-sectional view showing a main part of a conventional honeycomb structure extrusion apparatus. The main part of the apparatus for honeycomb structure extrusion molding of this invention is shown, (a) is principal part sectional drawing, (b) is the elements on larger scale of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Clasp, 12 ... Presser plate, 13 ... Front spacer, 14 ... Back spacer, 15 ... Back presser plate, 16 ... Inclined surface, 17, 18 ... Slit (discharge passage), 19 ... Supply passage, 20 ... Slit Part, 21 ... base part, 22 ... outer edge part, 24 ... boundary, 25a, 25b ... base member (pin), 26 ... outer peripheral inclined part (space), 28 ... counterbore part, 29 ... removal part.

Claims (4)

In addition to a base and a press plate that defines the outer wall of the honeycomb structure disposed on the outer peripheral side of the base, a honeycomb having a back press plate that is also disposed on the outer peripheral side of the base and adjusts the amount of clay to be extruded. An apparatus for extruding a structure,
The base has a cell portion composed of thin walls connected to each other and a slit (discharge passage) for discharging a honeycomb structure having an outer wall formed on the outermost peripheral side of the cell portion at one end and the other end at the other end. Connected to a number of supply passages independently provided up to a certain depth, a slit portion (discharge portion) having a slit (discharge passage) forms a flat base portion and an inclined surface inclined in the outer peripheral direction of the base portion. And an outer edge portion,
It said mouthpiece, to remove the base member constituting the slit disposed at the boundary between the base portion and the outer edge of the slit portion, between the back pressing plate and the die, thickness 1.0 Insert a back spacer of ~ 3.5mm, and
The slit ratio of the slit of the base portion (the slit length / the slit width) is 7 or more, the diameter of the outer edge portion is 1.2 times or less of the diameter of the base portion, and the inner diameter of the back pressing plate is the base portion The honeycomb structure extrusion molding apparatus is 1.0 to 1.1 times the diameter of the honeycomb structure. Said base member is removed, a honeycomb structure extrusion molding apparatus according to claim 1, counterbore portion formed is formed to be flat. The honeycomb structure extrusion molding apparatus according to claim 2, wherein a slit ratio (the slit length / the slit width) of the slits in the counterbore part is 0 to 6 . The honeycomb structure extrusion molding apparatus according to any one of claims 1 to 3 , wherein an outer wall thickness ratio (minimum outer wall thickness / cell wall thickness) of the honeycomb structure is 1.3 or more .

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