JP2012210581A - Ceramic filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic filter capable of reducing the clogging of cells due to local deposition of particulate when treating exhaust gas including the particulate.SOLUTION: The ceramic filter 1 has: a honeycomb structure part having porous partitioning walls 3 containing ceramics as a main component; and a plurality of cells 5, a center part of the honeycomb structure part is a one face-sealed honeycomb structure part 15 including: cells 5 in which only one end faces 7a are sealed; and cells 5 which is not sealed anywhere, the outer peripheral part of the honeycomb structure part is a both face sealed honeycomb structure part 17 including a structure in which cells 5 in which only one end faces 7a are sealed and cells 5 in which only the other end faces 7b are sealed are alternately lined.

Description

  The present invention relates to a ceramic filter that can be used as a filter for exhaust gas purification.

  The exhaust gas generated from the internal combustion engine contains particulate matter. After removing the particulate matter to a certain concentration or less, the exhaust gas must be released to the environment. In order to meet this requirement, it is common to remove particulate matter using a ceramic filter. In a ceramic filter, a plurality of cells are defined by porous partition walls mainly composed of ceramics, and a honeycomb shape (honeycomb structure) is formed. And in this ceramic filter, the cell penetrated from one end to the other end, and furthermore, only one end was plugged and the other end was plugged. The cells are arranged alternately. When exhaust gas is allowed to flow into a cell that opens at one end with respect to the ceramic filter, the other end on the opposite side of the cell is plugged. It is possible to pass through. Here, when passing the exhaust gas through the porous partition, the particulate matter in the exhaust gas is captured by the partition, and the particulate matter is reduced from the exhaust gas. Finally, exhaust gas is discharged from the other end to the outside with the concentration of the particulate matter reduced. That is, in this ceramic filter, when exhaust gas is applied to one end, each of the plurality of cells captures the exhaust gas and collects the particulate matter, and finally exhausts the exhaust gas with a reduced concentration of the particulate matter. (For example, Patent Documents 1 and 2).

JP 2009-195805 A JP 2006-326381 A

  However, in the ceramic filter, some cells may take in a larger amount of exhaust gas than the remaining cells. In such a case, an excessive amount of particulate matter is collected in the cell that takes in a large amount of exhaust gas. Clogging may occur.

  In view of the above problems, an object of the present invention is to provide a ceramic filter in which clogging of cells due to particulate matter is unlikely to occur when exhaust gas containing particulate matter is treated.

  The present invention achieves the above-mentioned object. Specifically, the following ceramic filter is provided.

[1] It has a honeycomb structure part including a porous partition wall mainly composed of ceramics and a plurality of cells that are partitioned by the partition wall and communicate from one end face to the other end face, and the center of the honeycomb structure part The portion is a single-side plugged honeycomb structure including the cells plugged only in the one end surface and the cells not plugged in any of the outer peripheral portions of the honeycomb structure. The double-sided plugged honeycomb structure including a structure in which the cells plugged only in the one end face and the cells plugged only in the other end face are alternately arranged, In the end face, the ceramic in which the width of the double-sided plugged honeycomb structure part is equal to or more than the number of the cells in any direction from the center of the other end face toward the outer periphery of the other end face Filter.

[2] The ceramic filter according to [1], wherein the number of the cells plugged on the other end face is 5 to 15% of the number of all the cells.

[3] With respect to the cell having the other end face plugged, the length of the plugged portion along the direction that the cell passes is 3 to 30 mm according to [1] or [2] The ceramic filter as described.

[4] In the cross section of the double-sided plugged honeycomb structure perpendicular to the direction in which the cells communicate, the cross-sectional area of the cell in which only the one end face is plugged is plugged only in the other end face. The ceramic filter according to any one of [1] to [3], which is smaller than a cross-sectional area of the stopped cell.

[5] A plurality of honeycomb segments each including a plurality of honeycomb segments each including a porous partition wall mainly composed of ceramics and a plurality of cells formed by partitioning from one end surface to the other end surface. The segment is plugged only on the one end face, the single-side plugged honeycomb segment including the cells plugged only on the one end face, and the cells not plugged in any one of them. A state in which one or more single-sided plugged segments are disposed in the center portion, including the cells and double-sided plugged honeycomb segments in which the cells plugged only in the other end face are alternately arranged. A ceramic filter in which the plurality of honeycomb segments are joined adjacent to each other with their side surfaces facing each other.

[6] The above [5], wherein the total number of the cells plugged at the other end face of the one-side plugged honeycomb segment is 5 to 15% of the number of all the cells in all the honeycomb segments. ] Ceramic filter as described in.

[7] In the above-mentioned [5] or [6], in the double-sided plugged honeycomb segment, the length of the plugged portion on the other end surface along the direction of the cell is 3 to 30 mm. The ceramic filter as described.

[8] In the cross section of the double-sided plugged honeycomb segment perpendicular to the direction in which the cells communicate, the cross-sectional area of the cell in which only the one end face is plugged is plugged only in the other end face. The ceramic filter according to any one of [5] to [7], which is smaller than a cross-sectional area of the formed cell.

  The ceramic filter of the present invention is less likely to cause clogging of cells due to particulate matter when exhaust gas containing particulate matter is treated.

It is a perspective view of one embodiment of the ceramics filter of the first invention. It is a perspective view when the ceramics filter shown in FIG. 1 is turned upside down. FIG. 2 is a cross-sectional view taken along line A-A ′ in FIG. 1. It is a figure for demonstrating a HAC structure. It is a perspective view of one embodiment of the ceramic filter of the second invention. It is a perspective view of a honeycomb segment. It is a schematic diagram of the exit side end face of the honeycomb filter (Example 14) of one embodiment of the second invention. It is a schematic diagram of the exit side end face of the honeycomb filter (Example 15) of one embodiment of the second invention. It is a schematic diagram of the exit side end face of the honeycomb filter (Example 16) of one embodiment of the second invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the present invention.

1. Ceramic filter of the first invention:
The ceramic filter of the first invention of the present application has a honeycomb structure portion including a porous partition wall mainly composed of ceramics and a plurality of cells that are partitioned by the partition wall and communicate from one end surface to the other end surface, The center part of the honeycomb structure part is a single-sided plugged honeycomb structure part including cells plugged only on one end face and cells not plugged in any of them, and the outer peripheral part of the honeycomb structure part Is a double-sided plugged honeycomb structure including a structure in which cells plugged only on one end face and cells plugged only on the other end face are alternately arranged.

  In the ceramic filter of the first invention, the honeycomb structure part is composed of a single-side plugged honeycomb structure part and a double-sided plugged honeycomb structure part. When the gas is applied from one end face to the double-sided plugged honeycomb structure, the gas can flow into the cell opening one end face. At this time, the gas flowing into the cells of the double-sided plugged honeycomb structure portion is plugged at the other end surface on the opposite side, so that the gas passes through the porous partition wall and is transferred to the adjacent cell. And finally exhaust the gas from the other end face. Here, when the gas passes through the porous partition walls, the particulate matter that cannot pass through the partition walls is captured. Therefore, when a gas is allowed to flow into the double-sided plugged honeycomb structure, the gas with a reduced concentration of particulate matter is discharged. That is, the gas can be purified by the double-sided plugged honeycomb structure.

  In the first invention, the single-side plugged honeycomb structure includes cells that are not plugged anywhere. When a gas is allowed to flow into such a cell, it passes through the cell as it is, and the gas is discharged from the opposite side. Thus, since the gas is only passed through the same cell from one end face to the other end face, the pressure loss is unlikely to increase. For this reason, even if the entire honeycomb structure is considered, pressure loss does not become excessively large when a gas flows through the inside of the honeycomb structure from one end face toward the other end face.

  The porous partition which has ceramics as a main component as used in this specification means that the partition contains 50 mass% or more of ceramics. In the ceramic filter of the first invention, the porous partition can contain cordierite or SiC as a main component. The plugging of the cells can be performed by, for example, closing the end portions of the cells with a plugging material containing ceramic as a main component. At this time, the same ceramic type as the main component of the partition wall can be used as the ceramic type as the main component of the plugging material.

  In general, in a ceramic filter with a honeycomb structure, when a gas is applied to one end face, the flow rate of the gas flowing into the cell is larger in the cell in the central part of the ceramic filter than in the cell in the outer peripheral part. Tend to be. Along with this, a large amount of particulate matter is more likely to flow into the central portion of the ceramic filter than to the outer peripheral portion. When the center portion of the ceramic filter includes a cell that is not plugged anywhere like the ceramic filter of the first invention, the particulate matter can be discharged as it is in this non-plugged cell. As a result, even when a large amount of gas flows, the collection of particulate matter can be kept small. Therefore, even when a large amount of gas flows into the ceramic filter, the cells in the central portion of the ceramic filter are unlikely to be clogged early by the particulate matter.

  In the ceramic filter according to the first aspect of the invention, since the center portion of the ceramic filter includes a cell whose one end face is plugged, when the gas is applied to the one end face, the ceramic filter Before flowing into the cell, the end of the cell is plugged to prevent the hand from going, and as a result, it can be distributed to flow to the outer peripheral portion of the ceramic filter. The outer peripheral portion of the ceramic filter to which the gas is distributed in this manner is a double-sided plugged honeycomb structure, and this double-sided plugged honeycomb structure has a high ability to collect particulate matter as described above. The particulate matter contained in can be reliably collected.

  Furthermore, in the ceramic filter of the first invention, the width of the double-sided plugged honeycomb structure portion is 2 in terms of the number of cells in the other end face in any direction from the center of the other end face toward the outer periphery of the other end face. There are more than that. The double-sided plugged honeycomb structure includes a structure in which cells plugged only at one end face and cells plugged only at the other end face are alternately arranged. That is, in the double-sided plugged honeycomb structure portion, when two or more cells are arranged, one or more cells always open at one end face of the ceramic filter. Based on this structure, the characteristics of the width of the double-sided plugged honeycomb structure portion on the other end face described above, in other words, focusing on one end face, in the ceramic filter of the first invention, In any direction from the center toward the outer periphery of one end face, at least one cell included in the double-sided plugged honeycomb structure portion is opened. Therefore, regardless of the location of the outer peripheral portion of the ceramic filter, the gas can be allowed to flow into the cells of the both-sealed honeycomb structure at the tip of the distribution by the above-described gas distribution. As a result, the particulate matter can be reliably collected by this double-sided honeycomb structure.

  In addition, in a ceramic filter with a honeycomb structure, when clogging occurs in some cells due to particulate matter, the gas flow changes due to clogging, and the gas flow rate is biased toward a predetermined cell. Cheap. In the ceramic filter according to the first aspect of the present invention, since the gas flow can be distributed before flowing into the ceramic filter by the function of plugging as described above, even when clogging occurs in some cells, Gas distribution according to the state in which such clogging occurs is easily performed, and as a result, the gas flow rate is less likely to be biased toward a predetermined cell.

  In the ceramic filter of the first invention, the number of cells plugged on the other end face is preferably 5 to 15% of the number of cells in all the figures. In the first invention, when the number of cells plugged on the other end face is 5% or more of the total number of cells, the particulate matter containing the particulate matter is sufficiently contained in the gas. It becomes possible to collect. In the first invention, if the number of cells plugged on the other end face is 15% or less of the number of all cells, the pressure loss when passing the gas through the ceramic filter is excessive. It will not grow.

  Moreover, in the ceramic filter of the first invention, from the viewpoint of not excessively increasing the pressure loss when the gas is passed through the ceramic filter, the plugged portion of the cell whose other end face is plugged is used. It is preferable that the length along the direction which a cell leads is 3-30 mm. Further, when removing the particulate matter collected by the ceramic filter by burning, the length along the direction of the plugged portion of the cell is 3 mm or more. Since the heat capacity of the portion is increased, the temperature of the filter is not easily increased rapidly, and as a result, the problem that the particulate matter is locally burned is less likely to occur.

  Further, in the ceramic filter of the first invention, from the viewpoint of enhancing the ability to collect particulate matter contained in the gas, one end face in the cross section of the double-sided plugged honeycomb structure perpendicular to the direction in which the cells pass It is preferable that the cross-sectional area of the cell plugged only in the cell is smaller than the cross-sectional area of the cell plugged only in the other end face. In the case of such a form, since the ratio of the total area of the part opened at one end surface increases, it becomes possible to flow more gas into the cell from one end surface, Since the area of the partition which contributes to collecting particulate matter increases, the amount of particulate matter to be collected can be increased.

  In addition, when a conventional ceramic filter is used, in order to avoid clogging of the cell, it must be used in combination with a technique for arranging a bypass path in parallel with the ceramic filter (for example, see Japanese Patent Laid-Open No. 3-15615). There are things that must be done. However, this conventional technique increases the size of the apparatus by newly adding a bypass path, and requires a mechanism for switching the flow of exhaust gas between the ceramic filter and the bypass path, resulting in a complicated structure. End up. Under such circumstances, there are cases where the technology for arranging the bypass path cannot be applied. According to the ceramic filter of the first aspect of the present invention, the clogging of the cell is less likely to occur, so the number of cases in which the technique of arranging the bypass path is not required increases, and as a result, the application range is expanded compared to the conventional ceramic filter be able to.

  Hereinafter, the content will be described in detail with reference to the embodiment of the ceramic filter of the first invention.

  FIG. 1 is a perspective view of an embodiment of the ceramic filter of the first invention. As shown in the figure, the ceramic filter 1 has a cylindrical outer peripheral wall 2, and the inside of the cylinder of the outer peripheral wall 2 is partitioned by partition walls 3 to form a honeycomb structure. As a result, the ceramic filter 1 has a partition wall 3 extending in the X direction and a Y direction perpendicular to the X direction when viewed from a cross section perpendicular to the direction in which the cylindrical outer peripheral wall 2 is removed (Z direction). A portion surrounded by the outer peripheral wall 3 is partitioned into quadrangular shapes like a grid paper by the extending partition walls 3, and cells 5 are formed in each partition. The cell 5 penetrates the inside surrounded by the outer peripheral wall 2 in the Z direction.

  Further, in the present ceramic filter 1, both ends in the Z direction are flattened by the edges of the partition walls 3 partitioned like the grid of the graph paper as described above, and form the end face 7a and the end face 7b. ing.

  As shown in FIG. 1, on the end surface 7a of the ceramic filter 1, the end portions of the cells 5 plugged by the plugging material 9 and the end portions of the cells 5 that are not plugged are alternated. The checkered pattern is formed by being lined up in a row.

  FIG. 2 is a perspective view when the ceramic filter 1 shown in FIG. 1 is turned upside down. In this figure, an end face 7b opposite to the end face 7a appears. As shown in the figure, on the end face 7 b of the ceramic filter 1, none of the end portions of the cell 5 in the center portion is plugged. Further, in the end face 7b of the present ceramic filter 1, at the outer peripheral portion surrounding the central portion, the end portion of the cell 5 plugged by the plugging material 9 and the end portion of the cell 5 that is not plugged A checkerboard pattern is formed by alternating the lines. In this outer peripheral portion, the cell 5 whose end portion is plugged with the end surface 7b is not plugged with the end surface 7a on the opposite side, while the end portion is plugged with the end surface 7b. The cell 5 that is not sealed is plugged at the end on the opposite end surface 7a. Therefore, in the outer peripheral portion of the honeycomb filter 1, the cells 5 plugged only on one end face 7a and the cells 5 plugged on the other end face 7b are alternately arranged.

  FIG. 3 is a cross-sectional view taken along the line A-A ′ in FIG. 1. As shown in the drawing, the plurality of cells 5 penetrates the inside surrounded by the outer peripheral wall 2 from the end surface 7a to the end surface 7b in the Z direction. Then, as described above, in the portion near the outer peripheral wall 2, that is, in the outer peripheral portion, only the end surface 7a is plugged with the plugging material 9, and only the end surface 7b is plugged with the plugging material 9. The plugged cells 5 are arranged alternately. That is, this outer peripheral portion is a double-sided plugged honeycomb structure 17. And in the center part, the cell 5 which plugged only the end surface 7b with the plugging material 9 and the cell 5 which is not plugged at all are located in a line. That is, this central portion is a single-side plugged honeycomb structure portion 15.

As shown, when exposed to the exhaust gas G ₁ to the end face 7a, the exhaust gas G ₁ is going to flow into the cells not plugged end face 7a. Here, as for the double-sided plugged honeycomb structure 17, when it proceeds in the Z direction as it is in the cell 5 into which the exhaust gas G ₁ flows, it reaches the plugging material 9 at the end face 7 b. Therefore, the exhaust gas G ₁ is forced to flow through the partition wall 3 and flow into the adjacent cell 5. In this case, particulate matter in the exhaust gas G ₁ are trapped in the partition wall 3, the exhaust gas G ₂ which has been purified to flow into the cell 5 of the next, and is discharged from the final end face 7b. Thus, double-sided plugged honeycomb structure portion 17, when the exhaust gases to flow therein G ₁ from the end face 7a, from the opposite end face 7b can be discharged exhaust gas G ₂ which has been purified.

In contrast, the one side-plugged honeycomb structure 15, the exhaust gas G ₁ is introduced from the end face 7a, as it is discharged from the opposite end faces 7b proceeds the same the cell 5 in the Z direction. Therefore, in one side-plugged honeycomb structure 15, by particulate matter in the exhaust gas G ₁ is attached to the partition wall 3, despite the fact that the small amount of particulate matter is trapped, many particulate matter It is discharged from the end face 7b. By suppressing the amount of particulate matter collected in this way, the single-side plugged honeycomb structure 15 in the central portion where a large amount of particulate matter is likely to flow in collects excessive particulate matter. As a result, it is possible to reduce the clogging of the cells 5 by the particulate matter.

In the present ceramic filter 1, the single-side plugged honeycomb structure 15 is plugged on the end surface 7 a side with the plugging material 9 in some cells 5, so that the single-side plugged honeycomb structure 15 is plugged. suppressing the flow rate of the exhaust gas G ₁ flowing into the structure 15, instead, is to increase the flow rate of the exhaust gas G ₁ to continue to flow into the high collecting capability sided plugged honeycomb structure portion 17. With such distributes the exhaust gas G ₁ to the double-sided plugged honeycomb structure portion 17, the double-sided plugged honeycomb structure 17 because of the high collecting capability and can trap particulate matter more effectively.

  FIG. 4 is an enlarged view of an end face of a honeycomb structure that can be used in the ceramic filter of the first invention. As shown in the drawing, in the present honeycomb structure, large cells 41 having a large cross-sectional area and small cells 43 having a small cross-sectional area are alternately arranged. When using this honeycomb structure, it is preferable to plug the end of the small cell 43 on one end face and plug the end of the large cell 41 on the other end face. In the case of such a configuration, a large amount of gas can be caused to flow into the large cell 41, and the surface area of the partition wall 3 constituting the large cell 41 is large, so that even if a large amount of gas flows. The particulate matter can be sufficiently collected.

2. Ceramic filter of the second invention:
The ceramic filter of the second invention of the present application has a plurality of honeycomb segments each including a porous partition wall mainly composed of ceramics and a plurality of cells that are partitioned by the partition wall and communicate from one end surface to the other end surface. A plurality of honeycomb segments, a single-side plugged honeycomb segment including cells plugged only at one end face and cells not plugged into any one end face, and plugging only one end face And a double-sided plugged honeycomb segment in which only the other end face is plugged, and a plurality of single-sided plugged segments are arranged in the central portion. The individual honeycomb segments are joined while adjoining each other with their side surfaces facing each other.

  In the ceramic filter according to the second aspect of the invention, the porous partition may contain cordierite or SiC as the main component. The plugging of the cells can be performed by, for example, closing the end portions of the cells with a plugging material containing ceramic as a main component. At this time, the same ceramic type as the main component of the partition wall can be used as the ceramic type as the main component of the plugging material.

  In the double-sided plugged honeycomb segment provided in the ceramic filter of the second invention, the gas is passed through the partition walls by the same mechanism as the double-sided honeycomb structure in the first invention described above, and particulate matter contained in the gas is collected. Is possible.

  In the second invention, the single-side plugged honeycomb segment includes cells that are not plugged anywhere. When gas flows into such a cell, the gas passes through the cell as it is and is discharged from the opposite side, so that the pressure loss can be kept small. Therefore, considering the entire ceramic filter, pressure loss does not become excessively large when a gas is flowed from one end surface to the other end surface inside the ceramic filter.

  Generally, in a ceramic filter in which a plurality of honeycomb segments are joined as in the second invention, when the gas is applied to one end face, the flow rate of the gas flowing into the honeycomb segment is There is a tendency that the number of segments is larger than the number of honeycomb segments in the outer peripheral portion. Along with this, the particulate matter tends to flow in a larger amount in the honeycomb segment in the central part of the ceramic filter than in the honeycomb segment in the outer peripheral part. If the single-side plugged honeycomb segment is included in the central part of the ceramic filter as in the ceramic filter of the second invention, even if a large amount of gas flows, the single-side plugged in the central part The honeycomb segment is less likely to locally collect a large amount of particulate matter. As a result, in the single-side plugged honeycomb segment in the central portion, it becomes difficult for cells to be clogged early by particulate matter.

  In the ceramic filter of the second invention, the total number of cells plugged at the other end face of the single-side plugged honeycomb segment is equal to the number of all cells in all honeycomb segments (that is, all the ceramic filter 5 to 15% of the number of cells). Here, the total number of cells plugged at the other end face of the single-side plugged honeycomb segment is, for example, 2 when the ceramic filter includes two single-side plugged honeycomb segments. It means the total number of cells plugged at the other end face of each single-side plugged honeycomb segment. In the second invention, the total number of cells plugged at the other end face of the single-sided plugged honeycomb segment is the number of all cells in all honeycomb segments (that is, the number of all cells of the ceramic filter). ) Of 5% or more, the particulate matter can be sufficiently collected. In the second invention, the total number of cells plugged on the other end face of the single-side plugged honeycomb segment is equal to the number of all cells in all honeycomb segments (that is, all cells of the ceramic filter). In the case of 15% or less of the number), the pressure loss when passing the gas through the ceramic filter does not become excessively large.

  In the ceramic filter of the second invention, from the viewpoint of not excessively increasing the pressure loss when the gas is passed through the ceramic filter, in the double-sided plugged honeycomb segment, the plugged portion of the other end face It is preferable that the length along the direction which a cell leads is 3-30 mm. Further, when removing the particulate matter collected by the ceramic filter by burning, the length along the direction of the plugged portion of the cell is 3 mm or more. Since the heat capacity of the portion is increased, the temperature of the filter is not easily increased rapidly, and as a result, the problem that the particulate matter is locally burned is less likely to occur.

  In addition, when a conventional ceramic filter is used, in order to avoid clogging of the cell, it must be used in combination with a technique for arranging a bypass path in parallel with the ceramic filter (for example, see Japanese Patent Laid-Open No. 3-15615). There are things that must be done. However, this conventional technique increases the size of the apparatus by newly adding a bypass path, and requires a mechanism for switching the flow of exhaust gas between the ceramic filter and the bypass path, resulting in a complicated structure. End up. Under such circumstances, there are cases where the technology for arranging the bypass path cannot be applied. According to the ceramic filter of the second invention, since clogging of the cell is less likely to occur, the number of cases in which a technique for arranging a bypass path is not required increases, and as a result, the application range is expanded as compared with the conventional ceramic filter. be able to.

  Hereinafter, the content will be described in detail with reference to the embodiment of the ceramic filter of the second invention.

  FIG. 5 is a perspective view of an embodiment of the ceramic filter of the second invention. As shown in the figure, the ceramic filter 40 has a cylindrical appearance whose outer periphery is covered with a coating material 34. The ceramic filter 40 is made by joining a total of 32 honeycomb segments 31 by joining the side surfaces 39 to each other via a joint portion 33.

  The honeycomb segment 31 constituting the ceramic filter 40 has a partition 3 extending in the X direction and a partition 3 extending in the Y direction perpendicular to the X direction when viewed in a cross section perpendicular to the length direction (Z direction). A portion surrounded by the outer peripheral wall 3 is divided into quadrilaterals like a grid of grid paper, and cells 5 are formed in each of the sections. The cell 5 penetrates the inside of the honeycomb segment 31 in the Z direction. Further, in the present ceramic filter 40, both ends in the Z direction are planar due to the edges of the partition walls 3 partitioned like a grid of square paper, and form an end face 7a and an end face 7b.

  These honeycomb segments 31 include a single-side plugged honeycomb segment 35 and a double-side plugged honeycomb segment 37. As shown in FIG. 5, in the ceramic filter 40, a total of 16 single-sided sealing segments 35 are arranged in the central portion in 4 rows in the vertical direction and 4 rows in the horizontal direction, and 4 on the outer sides of the four sides. Individual double-sided plugged honeycomb segments 37 are arranged.

As shown in FIG. 5, at the end surface 7b of the double-sided plugged honeycomb segment 37, the end portion of the cell 5 plugged by the plugging material 9 and the end portion of the cell 5 that is not plugged. A checkered pattern is formed by alternating and. In the double-sided plugged honeycomb segment 37, the end portions of the cells 5 that are not end-plugged with the end surface 7b are plugged with the end surface 7a. Therefore, in the double-sided plugged honeycomb segment 37, the cells 5 plugged only in the end surface 7a and the cells 5 plugged in the end surface 7b are alternately arranged. In duplex-plugged honeycomb segment 37, when exposed to the exhaust gas G ₁ to the end face 7a, the exhaust gas G1 is gradually flows into the cells which are not plugged end face 7a. Then, similarly to the double-sided plugged honeycomb structure 17 in the first invention described above, the exhaust gas G ₁ flowing into the cell 5 is forced to flow through the partition wall 3 and into the adjacent cell 5. At this time, the particulate matter in the exhaust gas G ₁ is captured by the partition walls 3, and the purified exhaust gas G ₂ flows into the adjacent cells 5. Thus, double-sided plugged honeycomb segment 37, when flowing a gas G ₁ from the end face 7a, from the opposite end face 7b can be discharged exhaust gas G ₂ which has been purified.

Further, none of the cells 5 is plugged on the end surface 7 b of the single-side plugged honeycomb segment 35. FIG. 6 is a perspective view of the single-side plugged honeycomb segment 35. As shown in the figure, at the end surface 7a of the single-side plugged honeycomb segment 35, the end portions of the cells 5 plugged by the plugging material 9 and the end portions of the cells 5 that are not plugged are included. A checkered pattern is formed by alternating the lines. That is, in the single-side plugged honeycomb segment 35, the cells 5 plugged only on the end surface 7a with the plugging material 9 and the cells 5 that are not plugged anywhere are arranged alternately. In one side-plugged honeycomb segment 35, when flowing a gas G ₁ from the end face 7a, as it discharges the exhaust gas G ₁ to the same the cell 5 from the opposite side to the end face 7b proceeds in the Z direction. Therefore, in the single-side plugged honeycomb segment 35, a small amount of particulate matter may be collected due to the particulate matter in the exhaust gas G1 adhering to the partition wall 3, but a large amount of particulate matter is collected on the end face 7b. It will be discharged from. By suppressing the amount of particulate matter collected in this way, the particulate matter is excessively collected by the single-side plugged honeycomb segment 35 in the central portion where a large amount of particulate matter is likely to flow. As a result, it is possible to reduce the clogging of the cells 5 by the particulate matter.

Further, in the present ceramic filter 40, the single-side plugged honeycomb segment 35 is plugged with the plugging material 9 in the end faces 7 a of some cells 5. suppressing the flow rate of the exhaust gas G ₁ flowing into the interior, but instead, are increasing the flow rate of the exhaust gas G ₁ to continue to flow into the high collecting capability sided plugged honeycomb segments 37. As a result, the particulate matter is distributed to the double-sided plugged honeycomb segments 37 so that the particulate matter can be reliably collected.

  Each of FIG. 7 to FIG. 9 is a plan view of an end face of the ceramic filter of one embodiment of the second invention. These ceramic filters 50a to 50c are made by combining honeycomb segments 31 having the same arrangement with respect to the shapes of cells and partition walls. As shown in the figure, each of the ceramic filters 50a to 50c has a single-sided honeycomb segment 35 in the center. And when increasing the ability to collect the particulate matter contained in the exhaust gas, the ratio of the number of the double-sided plugged honeycomb segments 37 may be increased. Regarding the ceramic filters 50a to 50c, the ratio of the double-sided plugged honeycomb segments 37 increases in the order of the ceramic filter 50a (FIG. 7), the ceramic filter 50b (FIG. 8), and the ceramic filter 50c (FIG. 9). As a result, the ability to collect particulate matter increases.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Examples 1 to 10 and Comparative Examples 1 and 2)
An inorganic powder containing alumina, kaolin, talc, and silica so as to have a cordierite composition after firing is mixed with an appropriate amount of an organic binder (methylcellulose), a pore-forming agent, and water, and then kneaded to prepare a clay. did. This kneaded material was formed into a honeycomb shape having a cylindrical appearance by extrusion molding to produce a molded body, and this molded body was dried and then fired to manufacture a honeycomb structure. In this honeycomb manufactured body, the inside surrounded by a cylindrical outer peripheral wall (thickness 6 mm) is partitioned by perpendicular partition walls, and has a diameter of 190.5 mm, a length of 304.8 mm, and a partition wall thickness of 0.3 mm. The cell pitch was 1.8 mm. Further, when viewed from a cross section perpendicular to the longitudinal direction of the honeycomb structure, the inside of the outer peripheral wall is partitioned into squares like a grid of grid paper by partition walls (in Table 1, “Square” Notation).

  For the honeycomb structure described above, the end portions of the cells are arranged on the end surface on the inlet side so that the end portions of the plugged cells and the end portions of the cells that are not plugged appear alternately. It was plugged with plugging material. As the plugging material, a material having cordierite as a main component was used as in the honeycomb structure. For the end face on the outlet side, plug the end of the cell so that the ratio (%) of the number of cells plugged on the end face on the outlet side to the number of all cells is the value shown in Table 1. Closed with materials. Plugging is performed from the outermost periphery of the end face on the outlet side, and when the outermost peripheral cells are plugged one by one, the plugging is performed on the cells in the inner row. Then, the treatment was sequentially performed from the outer peripheral side toward the center until the above-described ratio of the number of cells was reached. Therefore, as the ratio (%) of the number of cells plugged in the end face on the outlet side with respect to the number of all cells increases, the portion closer to the central portion is plugged. Note that the cells plugged at the end face on the outlet side were limited to the cells not plugged at the inlet side. Also. Table 1 shows the length of the plugged portion [the length of the plugging material in the length direction of the ceramic filter (direction in which the cells pass)]. The length of the plugged portion is measured by inserting a round bar (1.0 mm in diameter) longer than the length of the honeycomb structure into the cell and measuring the length of the round bar protruding from the honeycomb structure on a scale. This was done by measuring. At this time, 9 cells were randomly measured, and the arithmetic average value was taken as the length of the sealed portion.

  Regarding the ceramic filters of Examples 1 to 10 and Comparative Examples 1 and 2, in Table 1, when exhaust gas having a particulate matter (PM) concentration of 8 g / L was allowed to flow into the ceramic filter from the end face on the inlet side Particulate matter collection efficiency (%) (represented as “collection efficiency at 8 g / L of PM deposit” in Table 1), and each example and each comparative example for the pressure loss of the ceramic filter of Comparative Example 1 The pressure loss ratio (shown as “pressure loss ratio” in Table 1) is shown. The collection efficiency referred to in this specification is the ratio of the amount of particulate matter collected by the ceramic filter without being discharged from the end face on the outlet side to the amount of particulate matter flowing in from the end face on the inlet side (% ). Moreover, from the results of these collection efficiencies and pressure loss ratios, evaluation was made according to three levels of “excellent”, “good”, and “impossible”. “Excellent” has a collection efficiency of over 30%, a pressure loss ratio of less than 10%, and the length of the plugged portion is 3 mm or more, “Good” has a collection efficiency of over 30% and a pressure loss ratio of When the length of the plugged portion is 10% or more and 15% or less and less than 3 mm, “impossible” is when the collection efficiency is 30% or less and the pressure loss ratio is more than 15%.

(Examples 11 to 13 and Comparative Example 3)
An inorganic powder containing alumina, kaolin, talc, and silica so as to have a cordierite composition after firing is mixed with an appropriate amount of an organic binder (methylcellulose), a pore-forming agent, and water, and then kneaded to prepare a clay. did. This kneaded material was formed into a honeycomb shape having a cylindrical appearance by extrusion molding to produce a molded body, and this molded body was dried and then fired to manufacture a honeycomb structure. In this honeycomb manufactured body, an interior surrounded by a cylindrical outer peripheral wall (thickness: 6 mm) is partitioned by partition walls so that a cell has a square or octagonal cross section. The cells having the cross-sections are arranged so as to be alternately arranged (indicated as “HAC” in Table 1). The area of the cross section of the square cell is smaller than the area of the cross section of the octagonal cell. The honeycomb structure had a diameter of 190.5 mm, a length of 304.8 mm, a partition wall thickness of 0.3 mm, a cell pitch of 1.3 mm (octagonal cell), and 1.0 mm (square cell).

  For the above-described honeycomb structure, only cells having a square cross section on the end face on the inlet side are arranged in a checkered pattern by the end portions of the plugged cells and the end portions of the non-plugged cells. Was plugged. As the plugging material, a material having cordierite as a main component was used as in the honeycomb structure. For the end face on the outlet side, plug the end of the cell so that the ratio (%) of the number of cells plugged on the end face on the outlet side to the number of all cells is the value shown in Table 1. Closed with materials. Plugging is performed from the outermost periphery of the end face on the outlet side, and when the outermost peripheral cells are plugged one by one, the plugging is performed on the cells in the inner row. Then, the treatment was sequentially performed from the outer peripheral side toward the center until the above-described ratio of the number of cells was reached. Therefore, as the ratio (%) of the number of cells plugged in the end face on the outlet side with respect to the number of all cells increases, the portion closer to the central portion is plugged. Note that the cells plugged at the end face on the outlet side were limited to cells having an octagonal cross section. The length of the plugged portion [the length of the plugging material in the length direction of the ceramic filter (direction in which the cells pass)] was 10 mm (Table 1). In addition, about the measurement of the length of the plugged part, it is the same as that of Example 1 etc. which were mentioned above.

  For the ceramic filters of Examples 11 to 13 and Comparative Example 3, Table 1 shows particles when exhaust gas having a particulate matter (PM) concentration of 8 g / L is allowed to flow into the ceramic filter from the end face on the inlet side. Collection efficiency (%) of the particulate matter (in Table 1, “collection efficiency at 8 g / L of PM deposit”), pressure loss of each example and each comparative example relative to the pressure loss of the ceramic filter of Comparative Example 3 Ratio (indicated as “pressure loss ratio” in Table 1). Table 1 also shows the three-stage evaluation of the results of the collection efficiency and pressure loss ratio.

(Examples 14 to 16)
An appropriate amount of an organic binder (methylcellulose), a pore-forming agent, and water was mixed with the SiC powder, and then kneaded to prepare a clay. The kneaded material was formed into a honeycomb shape having a quadrangular prism-like appearance by extrusion molding to produce a formed body, and the formed body was dried and then fired to prepare a honeycomb segment. The honeycomb segment is partitioned so that the cross section of the cell is square (denoted as “Square” in Table 1) by partition walls surrounded by a rectangular column-shaped cylindrical outer peripheral wall (thickness 0.5 mm). The end surface was 36 mm long × 36 mm wide, the length was 304.8 mm, the partition wall thickness was 0.3 mm, and the cell pitch was 1.8 mm.

  The honeycomb segment is plugged with a plugging material so that the end face on the inlet side has a checkered pattern in which the cell opening portions plugged and the opening portions of the cells not plugged appear alternately. gave. As the plugging material, a material mainly composed of SiC was used. Further, for some of the honeycomb segments whose end faces on the inlet side were plugged, the end faces on the outlet side were plugged so as to have a checkered pattern. In addition, the plugging of the outlet end face was performed on a cell whose inlet side end face was not plugged. Here, a honeycomb segment in which end faces on the inlet side and the outlet side are plugged is referred to as a double-sided plugged honeycomb segment, and a honeycomb segment in which only the end face on the inlet side is plugged is referred to as a single-side plugged segment. Also. The length of the plugged portion [the length of the plugging material in the length direction of the ceramic filter (direction in which the cells pass)] was 6 mm (Table 1). The measurement of the length of the plugged portion is the same as in Example 1.

  Subsequently, a total of 36 honeycomb segments, 6 in the vertical direction and 6 in the horizontal direction, were arranged, and the side surfaces were bonded to each other with a bonding material to prepare a bonded honeycomb body. A ceramic filter having a diameter of 190.5 mm and a length of 304.8 was manufactured by grinding the outer periphery of the bonded honeycomb body into a cylindrical shape and then coating the outer periphery. 7 (Embodiment 14), FIG. 8 (Embodiment 15), and FIG. 9 (Embodiment 16) are plan views of the outlet side end face of the honeycomb filter. Regarding the total ratio (%) of the number of cells plugged at the end face on the outlet side of the single-side plugged honeycomb segment with respect to the number of all cells of the honeycomb filter, Example 16 is 8%, Example 15 is 15% and Example 16 was 41%.

(Comparative Example 4)
A ceramic filter was manufactured in the same manner as in Example 14, except that a total of 36 honeycomb segments were made into single-side plugged honeycomb segments to prepare a honeycomb joined body.

  For the ceramic filters of Examples 14 to 16 and Comparative Example 4, trapping of the particulate matter when exhaust gas having a particulate matter (PM) concentration of 8 g / L was allowed to flow into the ceramic filter from the end face on the inlet side. Collection efficiency (%) (in Table 1, “collection efficiency at 8 g / L of PM deposit”), ratio of pressure loss of each example and each comparative example to pressure loss of ceramic filter of comparative example 4 (table Table 1 shows “pressure loss ratio” in FIG. Table 1 also shows the three-stage evaluation of the results of the collection efficiency and pressure loss ratio.

  The present invention can be used as a ceramic filter that can be used as a filter for exhaust gas purification.

1: ceramic filter, 2: outer peripheral wall, 3: partition wall, 5: cell, 7, 7a, 7b: end face, 9: plugging, 10: center of gravity, 11: central portion, 13: outer peripheral portion, 15: one side Sealed honeycomb structure, 17: Double-sided plugged honeycomb structure, 31: Honeycomb segment, 33: Joined part, 34 :, 35: Single-sided plugged honeycomb segment, 37: Double-sided plugged honeycomb segment, 39: Side 40: Ceramics filter, 41: Large cell, 43: Small cell, 50a-50c: Ceramics filter.

Claims (8)

Having a honeycomb structure part comprising a porous partition wall mainly composed of ceramics and a plurality of cells defined by the partition wall and extending from one end surface to the other end surface;
The central part of the honeycomb structure part is a single-sided plugged honeycomb structure part including the cells plugged only on the one end face and the cells not plugged in any of them.
A double-sided plugged honeycomb in which the outer peripheral portion of the honeycomb structure portion includes a structure in which the cells plugged only in the one end face and the cells plugged only in the other end face are alternately arranged. Structure part,
In the other end face, a ceramic in which the width of the double-sided plugged honeycomb structure part is equal to or more than the number of the cells in any direction from the center of the other end face toward the outer periphery of the other end face. filter.   2. The ceramic filter according to claim 1, wherein the number of the cells plugged on the other end face is 5 to 15% of the number of all the cells.   The ceramic filter according to claim 1 or 2, wherein the length of the plugged portion of the cell plugged at the other end surface is 3 to 30 mm along a direction in which the cell communicates.   In the cross-section of the double-sided plugged honeycomb structure perpendicular to the direction in which the cells communicate, the cross-sectional area of the cell plugged only on the one end face is plugged only on the other end face. The ceramic filter as described in any one of Claims 1-3 smaller than the cross-sectional area of the said cell. A plurality of honeycomb segments each including a porous partition wall mainly composed of ceramics and a plurality of cells that are partitioned by the partition wall and communicate from one end surface to the other end surface;
The plurality of honeycomb segments are:
A single-side plugged honeycomb segment comprising the cells plugged only on the one end face, and the cells not plugged in any one of them,
The double-sided plugged honeycomb segments in which the cells plugged only in the one end surface and the cells plugged only in the other end surface are alternately arranged,
A ceramic filter in which the plurality of honeycomb segments are bonded to each other with their side surfaces facing each other in a state where one or more single-side plugged segments are arranged in a central portion.   The total number of the cells plugged at the other end face of the single-side plugged honeycomb segment is 5 to 15% of the number of all the cells in all the honeycomb segments. Ceramic filter.   7. The ceramic filter according to claim 5, wherein in the double-sided plugged honeycomb segment, a length of the plugged portion on the other end surface along the direction of the cell is 3 to 30 mm.   In the cross section of the double-sided plugged honeycomb segment perpendicular to the direction in which the cells communicate, the cross-sectional area of the cell plugged only on the one end face is plugged only on the other end face. The ceramics filter as described in any one of Claims 5-7 smaller than the cross-sectional area of a cell.

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