JP5877740B2 - Bonded honeycomb filter - Google Patents

Description

  The present invention relates to a honeycomb filter and a bonded honeycomb filter. More specifically, the present invention relates to a honeycomb filter that has a low pressure loss and can suppress excessive accumulation of soot and ash, and a bonded honeycomb filter using such a honeycomb filter.

  Gases discharged from internal combustion engines such as diesel engines and direct-injection gasoline engines and various combustion apparatuses contain a large amount of particulate matter mainly composed of soot. If such particulate matter is released into the atmosphere as it is, it may cause environmental pollution. Therefore, an exhaust gas purification filter is mounted on an exhaust system in an internal combustion engine, a combustion apparatus, or the like to collect particulate matter. As such an exhaust gas purification filter, a diesel particulate filter (hereinafter sometimes referred to as “DPF”) may be mentioned.

  As such a DPF, for example, “a porous partition wall defining a plurality of cells is provided, and plugged portions are provided at one end portion of a predetermined cell and the other end portion of the remaining cells. A honeycomb structure is used.

  In such a DPF, the excessive purification of soot and ash (ash) on the surface of the partition wall significantly reduces the filter purification function. Moreover, when soot and ash (ash) accumulate excessively on the surface of a partition, pressure loss will also increase. For this reason, a honeycomb structure has been proposed in which measures are taken to alleviate excessive accumulation of soot and ash (see, for example, Patent Documents 1 and 2).

JP 2009-236067 A JP 2009-154124 A

  In recent years, exhaust gas regulations tend to be stricter, but in some emerging countries, exhaust gas regulations may be relaxed compared to developed countries. In particular, the conventional plugged honeycomb structure has a high manufacturing cost, and development of an exhaust gas purification filter that meets the needs (in other words, exhaust gas regulations) of each country is desired.

  Further, in order to mount an exhaust gas purification filter on an automobile already used in an emerging country or the like, an exhaust gas purification filter for retrofit (that is, retrofit) is required. Such a retrofit exhaust gas purification filter is generally not equipped with a regeneration control device that regenerates the function of the filter by heating and burning collected soot and the like. For this reason, in the conventional exhaust gas purification filter, if soot accumulates excessively, there is a problem that the purification performance of the filter deteriorates. There is also a problem that the pressure loss of the exhaust gas purification filter significantly increases due to excessive accumulation of soot. In emerging countries where such an exhaust gas purification filter for retrofit is required, fuel that generates more ash by combustion may be used as fuel for automobiles. In such a case, more ash accumulates on the exhaust gas purification filter, and thus the problem that the purification performance of the filter deteriorates or the pressure loss increases becomes more conspicuous.

  Although the honeycomb structures described in Patent Documents 1 and 2 described above can suppress excessive accumulation of soot and ash to some extent, the honeycomb structure of the exhaust gas purification filter that can further suppress excessive accumulation of soot and ash. Development is desired. In addition, the honeycomb structures described in Patent Documents 1 and 2 described above are required to develop an exhaust gas purification filter that has a large pressure loss in an initial use state and has a reduced pressure loss.

  The present invention has been made in view of the above-described problems. The present invention provides a honeycomb filter that has a low pressure loss and can suppress excessive accumulation of soot and ash, and a bonded honeycomb filter using such a honeycomb filter.

  According to the present invention, the following honeycomb filter and bonded honeycomb filter are provided.

[1] A polygonal cylindrical outer peripheral wall having a first end surface and a second end surface, and a plurality of outer peripheral walls disposed within the outer peripheral wall and having an opening on at least one end surface of the first end surface and the second end surface. A porous partition wall that defines a cell, the partition wall has a porosity of 40 to 70%, and the plurality of cells have a rotation axis extending in a direction extending from the first end surface to the second end surface. The outer periphery is defined by the partition so as to draw a spiral, and at least one cell located on the outer peripheral side of the plurality of cells is on the way from the first end surface to the second end surface. A joined type honeycomb comprising a plurality of honeycomb filters blocked by walls , wherein the plurality of honeycomb filters are joined in a state of being arranged adjacent to each other so that the surfaces of the outer peripheral walls face each other. filter .

[2] The joined honeycomb filter according to [1], wherein the outer peripheral wall has a quadrangular cylindrical shape or a triangular cylindrical shape.

[3] The outer peripheral wall has a rectangular tube shape, and a cell formed so as to draw a spiral from the first end surface to the second end surface with respect to the rotation axis from the first end surface to the second end surface The joined honeycomb filter according to [2], wherein the rotation angle is 30 to 240 °.

[4] The outer peripheral wall has a quadrangular cylindrical shape, and a cell formed so as to draw a spiral from the first end surface to the second end surface with respect to the rotation axis from the first end surface to the second end surface The joined honeycomb filter according to [2], wherein the rotation angle is 30 to 240 °.

[ 5 ] The bonded honeycomb filter according to [ 4 ], further including an outer wall that is ground so that the outer peripheral portions of the plurality of bonded honeycomb filters are ground and covers the ground side surfaces. .

Ha Nikamufiruta includes an outer peripheral wall of the polygonal tubular shape having a first end face and second end face, located inside the outer peripheral wall, a plurality of cells having an opening on at least one end face of the first end face and second end face And a porous partition wall that forms a partition . In Ha Nikamufiruta, the porosity of the partition walls is 40 to 70%. The plurality of cells are partitioned by the partition so as to draw a spiral with respect to the rotation axis in the direction extending from the first end surface to the second end surface, and at least one of the plurality of cells positioned on the outer peripheral side The cell is blocked by the outer peripheral wall on the way from the first end surface to the second end surface.

Ha Nikamufiruta can be suitably used as a filter of the low collecting efficiency emission standards particulate matter corresponding to the loose emission regulations. According to Ha Nikamufiruta, it is possible to suppress the reduction of pressure loss, and soot and ash is excessively deposited. For example, when the first end surface side of the honeycomb filter is an exhaust gas inflow surface, the exhaust gas flowing from the opening of the cell on the first end surface passes through the spiral cell and moves to the second end surface side. At this time, soot and ash in the exhaust gas flowing into the cell blocked by the outer peripheral wall on the way from the first end surface to the second end surface is trapped by the partition wall forming the cell or the outer peripheral wall blocking the cell. Be collected. Further, the exhaust gas that has flowed into the cell formed so as to draw a spiral from the first end surface to the second end surface moves along the spiral flow, and a part of the exhaust gas passes through the porous partition wall. Thereby, a part of soot and ash in exhaust gas is collected by the porous partition. Moreover, even if the exhaust gas does not permeate the partition, soot and ash having a mass greater than that of air is collected by being attached to the surface of the partition by the inertial force (in other words, centrifugal force) generated by the spiral flow. Sometimes. Further, the remaining soot and ash in the exhaust gas flowing into the cell formed to draw a spiral are discharged together with the purified gas from the opening of the cell on the second end face.

Thus, Ha Nikamufiruta the ends of cells other than the cells that are blocked by the outer peripheral wall, because of the opening at the first end face and second end face, the pressure loss is very low. In addition, a part of the soot and ash in the exhaust gas flowing into the cell formed so as to draw a spiral from the first end surface to the second end surface is collected by the partition walls that define the cell, and the remaining soot And ash are discharged from the opening of the second end face together with the purified gas. Therefore, excessive soot and ash are hardly deposited on the surface of the partition wall. As described above, Ha Nikamufiruta is on the surface of the partition wall, for soot and ash are not easily excessively deposited, the playback control for playing the function of the filter by heat burns the captured soot, etc. No equipment is required. Therefore, Ha Nikamufiruta can be used favorably as an exhaust gas purifying filter for retrofit. In the cells blocked by the outer peripheral wall, soot and ash accumulate over time, but the effect on the purification performance of the filter and the increase in pressure loss is extremely small.

Further, joined type honeycomb filter of the present invention, Ha Nikamufiruta described above, comprises a plurality, the plurality of honeycomb filter, in a state in which the surfaces on each of the outer peripheral wall of each other are disposed adjacent to face It has been joined. Joined type honeycomb filter of the present invention to achieve the same effect as c Nikamufiruta.

  In addition, the bonded honeycomb filter of the present invention may further include an outer wall disposed so as to cover the ground side surface by grinding the outer peripheral portion of the plurality of bonded honeycomb filters. . Thereby, the outer periphery shape of a joining type honeycomb filter can be made into a desired shape, maintaining the effect mentioned above.

An embodiment of the Ha Nikamufiruta is a perspective view schematically showing. An embodiment of the Ha Nikamufiruta is a side view schematically showing. Fig. 3 is a plan view schematically showing a first end surface of the honeycomb filter shown in Fig. 2. It is sectional drawing which shows typically the A-A 'cross section in FIG. FIG. 3 is a cross-sectional view schematically showing a B-B ′ cross section in FIG. 2. It is sectional drawing which shows typically the C-C 'cross section in FIG. Fig. 3 is a plan view schematically showing a second end face of the honeycomb filter shown in Fig. 2. In one embodiment of the Ha Nikamufiruta, the cell is a schematic diagram for explaining a state of being formed so as to draw a spiral. Another embodiment of the Ha Nikamufiruta is a perspective view schematically showing. Another embodiment of the Ha Nikamufiruta is a side view schematically showing. Fig. 7 is a plan view schematically showing a first end surface of the honeycomb filter shown in Fig. 6. FIG. 7 is a cross-sectional view schematically showing a D-D ′ cross section in FIG. 6. It is sectional drawing which shows the E-E 'cross section in FIG. 6 typically. FIG. 7 is a plan view schematically showing a second end face of the honeycomb filter shown in FIG. 6. It is a perspective view showing a honeycomb structure body before grinding in the process of manufacturing a c Nikamufiruta. It is a top view which shows typically the 1st end surface of the honeycomb structure before the grinding process shown in FIG. FIG. 3 is a perspective view schematically showing a honeycomb filter in which an outer peripheral wall is disposed on an outer peripheral surface of a honeycomb structure after grinding. 1 is a perspective view schematically showing one embodiment of a bonded honeycomb filter of the present invention. It is a perspective view which shows typically other embodiment of the joining type honeycomb filter of this invention. It is a perspective view which shows typically other embodiment of the joining type | mold honeycomb filter of this invention.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. The present invention is not limited to the following embodiments. It should be understood that modifications and improvements as appropriate to the following embodiments are also included in the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It is.

(1) Honeycomb structure:
First, a description will be given of an embodiment of a wafer Nikamufiruta. Figure 1 is a perspective view schematically showing one embodiment of a c Nikamufiruta. Figure 2 is a side view schematically showing an embodiment of a wafer Nikamufiruta. 3A is a plan view schematically showing a first end surface of the honeycomb filter shown in FIG. FIG. 3B is a cross-sectional view schematically showing a cross section AA ′ in FIG. 2. 3C is a cross-sectional view schematically showing a BB ′ cross section in FIG. 2. 3D is a cross-sectional view schematically showing a CC ′ cross-section in FIG. 2. FIG. 3E is a plan view schematically showing a second end face of the honeycomb filter shown in FIG. Figure 4 shows, in an embodiment of the Ha Nikamufiruta, the cell is a schematic diagram for explaining a state of being formed so as to draw a spiral.

  As shown in FIGS. 1 to 4, the honeycomb filter 100 of the present embodiment includes a polygonal cylindrical outer peripheral wall 3 having a first end surface 11 and a second end surface 12, and a porous disposed inside the outer peripheral wall 3. Quality partition wall 1. In the honeycomb filter 100 shown in FIGS. 1 to 4, the outer peripheral wall 3 has a rectangular tube shape. A plurality of cells 2 are defined by partition walls 1 arranged inside the outer peripheral wall 3. In the honeycomb filter of the present embodiment, the porosity of the partition wall 1 is 40 to 70%.

  In the honeycomb filter 100 of the present embodiment, the plurality of cells 2 have an opening on at least one end face of the first end face 11 and the second end face 12. As shown in FIGS. 3A to 3E, the plurality of cells 2 are partitioned by the partition wall 1 so as to draw a spiral with respect to the rotation axis L in the direction extending from the first end surface 11 to the second end surface 12. . That is, the partition wall 1 that defines the cell 2 is disposed inside the outer peripheral wall 3 having a rectangular tube shape in a state twisted with respect to the rotation axis L. Hereinafter, the “direction extending from the first end surface 11 to the second end surface 12” may be referred to as “the axial direction of the honeycomb filter”. In the present invention, the term “spiral” refers to a spiral coil having a three-dimensional curved shape.

  For example, FIG. 3A is a plan view schematically showing the first end surface 11 of the honeycomb filter 100. On the first end surface 11, the lattice-like partition walls 1 that define the cells 2 are arranged so as to extend in parallel to the xy direction of the paper surface. FIG. 3B is a cross-sectional view showing a cross section perpendicular to the axial direction of the honeycomb filter in a portion having a length that is ¼ of the axial length from the first end surface 11 of the honeycomb filter 100. In the cross section shown in FIG. 3B, the grid-like partition walls 1 are arranged in a state of being rotated 15 ° clockwise (in other words, clockwise) with respect to the xy directions on the paper surface. . That is, from the first end surface 11 of the honeycomb filter 100, the cell 2 defined by the partition wall 1 has a spiral trajectory corresponding to 15 ° in a portion that is ¼ of the axial length. .

  FIG. 3C is a cross-sectional view showing a cross section perpendicular to the axial direction of the honeycomb filter in a portion having a length of 2/4 of the axial length from the first end surface 11 of the honeycomb filter 100. FIG. 3D is a cross-sectional view showing a cross section perpendicular to the axial direction of the honeycomb filter in a portion having a length that is 3/4 of the axial length from the first end surface 11 of the honeycomb filter 100. In the cross section shown in FIG. 3C, the grid-like partition walls 1 are arranged in a state of being rotated 30 ° clockwise with respect to the xy directions on the paper surface. Further, in the cross section shown in FIG. 3D, the grid-like partition walls 1 are arranged in a state of being rotated by 45 ° clockwise with respect to the xy directions on the paper surface. That is, from the first end surface 11 of the honeycomb filter 100, the cell 2 defined by the partition wall 1 has a spiral trajectory corresponding to 30 ° in a portion that is 2/4 of the axial length. . In addition, from the first end face 11 of the honeycomb filter 100, the cell 2 partitioned by the partition wall 1 in a portion having a length of 3/4 of the axial length has a spiral trajectory corresponding to 45 °. . The “rotation angle” in each cross section described above is a rotation angle with respect to the rotation axis L with respect to the position of the cell 2 on the first end surface 11.

  FIG. 3E is a plan view schematically showing the second end face 12 of the honeycomb filter 100. On the second end face 12, the grid-like partition walls 1 that define the cells 2 are arranged in a state of being rotated by 60 ° in the clockwise direction with respect to each of the xy directions on the paper surface. As described above, in the honeycomb filter 100 of the present embodiment illustrated in FIGS. 1 to 4, the plurality of cells 2 draw a spiral with respect to the rotation axis L in the direction extending from the first end surface 11 to the second end surface 12. Is formed. In the honeycomb filter 100 of the present embodiment, the rotation angle from the first end surface 11 to the second end surface 12 with respect to the rotation axis L is 60 °. Hereinafter, the “rotation angle with respect to the rotation axis L from the first end surface 11 to the second end surface 12” may be referred to as “spiral rotation angle”. This helical rotation angle can be said to be the phase of the cell with respect to the rotation axis L in the first end face 11 and the second end face 12.

  And in the honey-comb filter 100 of this embodiment, the outer peripheral wall 3 is a polygonal cylinder shape (in FIGS. 1-4), it is a square cylinder shape. Therefore, at least one cell 2 b located on the outer peripheral side of the plurality of cells 2 is blocked by the outer peripheral wall 3 on the way from the first end surface 11 to the second end surface 12. That is, as described so far, in the honeycomb filter 100 of the present embodiment, all the cells 2 are formed so as to draw a spiral in the axial direction of the honeycomb filter 100 with the rotation axis L as the rotation center. ing. Here, in at least one cell 2b located on the outer peripheral side, the spiral orbit having the rotation axis L as the rotation center is cut off by the outer peripheral wall 3 having a square cylindrical shape. For this reason, at least one cell 2b located on the outer peripheral side is blocked by the outer peripheral wall 3 on the way from the first end surface 11 to the second end surface 12. Hereinafter, the “cell 2b blocked by the outer peripheral wall 3” may be referred to as “blocking spiral cell 2b”. The “cell 2a formed so as to maintain a spiral trajectory from the first end surface 11 to the second end surface 12” may be referred to as “spiral cell 2a”. A cell in which a part of the cell 2 is partitioned by the outer peripheral wall 3 and the flow path of the cell 2 is not completely blocked is included in the “spiral cell”.

  In the honeycomb filter 100 of the present embodiment, it is preferable that all the cells 2 are formed so as to draw a spiral in the same rotation direction with respect to one rotation axis L. In addition, at the same position in the axial direction of the honeycomb filter 100, it is preferable that the rotation angles of the spirals of all the cells 2 are the same. That is, as shown in FIG. 4, when the spiral rotation angle from the first end surface 11 to the second end surface 12 is 60 °, all the cells 2 are in the same rotation direction with respect to the rotation axis L, and It is preferable to draw spirals that have the same rotation angle at the same position in the axial direction. Here, it demonstrates still in detail, referring FIG. 4 that the cell 2 is formed so that a spiral may be drawn. In FIG. 4, the spiral trajectories of the cells 2p, 2q, 2r, 2s, 2t, and 2u from the first end surface 11 to the second end surface 12 (see FIG. 1) are indicated by broken lines. And in FIG. 4, the opening position in the 2nd end surface of cell 2p, 2q, 2r, 2s, 2t, 2u is shown by the rectangle to which the wavy line was attached | subjected. For example, the cell 2p in FIG. 4 is the cell having the shortest distance from the rotation axis L. On the other hand, cells such as the cell 2s and the cell 2t are cells whose distance from the rotation axis L is longer than that of the cell 2p. The rotation angles of the respective spirals in the cells 2p, 2q, 2r, 2s, 2t are all 60 °. The cell 2u is the above-described blocking spiral cell, and the flow path of the cell 2u is blocked by the outer peripheral wall 3 on the way from the first end surface 11 to the second end surface 12 (see FIG. 1).

  The honeycomb filter 100 of the present embodiment as shown in FIGS. 1 to 4 can be suitably used as a filter with low collection efficiency corresponding to exhaust gas regulations in which particulate matter emission standards are loose. According to the honeycomb filter 100 of the present embodiment, pressure loss can be reduced, and excessive accumulation of soot and ash can be suppressed. For example, when the first end face 11 side of the honeycomb filter 100 is an exhaust gas inflow face, the exhaust gas flowing in from the opening of the cell 2 on the first end face 11 passes through the spiral cell 2 and passes through the second end face 12. Move to the side. At this time, soot and ash in the exhaust gas flowing into the blocking spiral cell 2b are collected by the partition wall 1 that defines the blocking spiral cell 2b or the outer peripheral wall 3 that blocks the blocking spiral cell 2b.

  The exhaust gas that has flowed into the spiral cell 2a moves along the spiral flow, and a part thereof passes through the porous partition wall 1. That is, the exhaust gas moving along the spiral flow from the first end surface 11 to the second end surface 12 has an inertial force in the axial direction of the honeycomb filter and an inertial force (in other words, centrifugal force) due to the spiral trajectory. Arise. Due to the inertial force, the exhaust gas moving in the spiral cell 2a passes through the partition wall 1 partitioning the outside of the spiral cell 2a, and at the same time, part of the soot and ash in the exhaust gas is porous partition wall 1 Collected by. Even if the exhaust gas does not permeate the partition wall 1, soot and ash having a mass greater than that of air may be collected by being attached to the surface of the partition wall 1 due to the inertial force generated by the spiral flow. Further, the remaining soot and ash in the exhaust gas flowing into the spiral cell 2a is discharged from the opening of the spiral cell 2a on the second end face 12 together with the purified gas.

  Thus, the honeycomb filter 100 of the present embodiment has a very low pressure loss because both ends of the spiral cell 2a other than the blocking spiral cell 2b are open at the first end surface 11 and the second end surface 12. It is. Further, in the honeycomb filter 100 of the present embodiment, not all the soot and ash in the exhaust gas are collected by the partition walls 1, but a part of the soot and ash is opened in the spiral cell 2a of the second end face 12. From the part, it is discharged together with the purified gas. Therefore, excessive soot and ash are difficult to deposit on the surface of the partition wall 1.

  In addition, since the honeycomb filter 100 according to the present embodiment is difficult to excessively accumulate soot and ash on the surface of the partition wall 1, a regeneration control device is not required. The regeneration control device regenerates the function of the filter by heating and burning the collected soot and the like. For this reason, the honeycomb filter 100 of this embodiment can be favorably used as an exhaust gas purification filter for retrofit. Although soot and ash are deposited over time in the blocking spiral cell 2b, the effect on the collection efficiency and pressure loss due to deposition of soot and the like is extremely small.

  The outer peripheral wall 3 having a polygonal cylinder shape is preferably a right-angle cylinder configured such that each side surface 13 is perpendicular to the first end surface 11 and the second end surface 12. Moreover, it is preferable that the outer peripheral wall 3 is a thing of a square cylinder shape or a triangular cylinder shape. In the honeycomb filter 100 of the present embodiment, at least one cell 2 located on the outer peripheral side is blocked by the outer peripheral wall 3 on the way from the first end surface to the second end surface, as in the cell 2u shown in FIG. ing. That is, the cell 2u is a blocking spiral cell 2b. When the outer peripheral wall 3 has a square tube shape or a triangular tube shape, when the cell 2 located on the outer peripheral side draws a spiral, the cell is formed by the outer peripheral wall 3 even if the rotation angle of the spiral is relatively small. The two flow paths are easily blocked. For example, even if the outer peripheral wall is a hexagonal cylinder shape or an octagonal cylinder shape, if the cells located on the outer peripheral side are blocked by the outer peripheral wall, the same as the honeycomb filter 100 shown in FIGS. An effect can be obtained. However, in the case of a hexagonal cylinder shape or an octagonal cylinder shape, it may be necessary to increase the rotation angle of the spiral. That is, the torsion of the partition wall 1 that defines the cell 2 with respect to the rotation axis L may increase, and the strength of the honeycomb filter 100 may decrease.

Here, a description of another embodiment of Ha Nikamufiruta. Figure 5 is a perspective view schematically showing another embodiment of Ha Nikamufiruta. Figure 6 is a side view schematically showing another embodiment of Ha Nikamufiruta. FIG. 7A is a plan view schematically showing a first end face of the honeycomb filter shown in FIG. FIG. 7B is a cross-sectional view schematically showing a DD ′ cross-section in FIG. 6. FIG. 7C is a cross-sectional view schematically showing the EE ′ cross-section in FIG. 6. FIG. 7D is a plan view schematically showing a second end face of the honeycomb filter shown in FIG. 6.

  A honeycomb filter 200 shown in FIGS. 5 to 7D includes a triangular cylindrical outer peripheral wall 23 having a first end surface 31 and a second end surface 32, and a porous partition wall 21 disposed inside the outer peripheral wall 23. It is provided. A plurality of cells 22 are defined by partition walls 21 arranged inside the outer peripheral wall 23. The plurality of cells 22 have an opening on at least one of the first end surface 31 and the second end surface 32. Similar to the honeycomb filter of the first embodiment, the porosity of the partition walls 21 is 40 to 70%.

  Also in the honeycomb filter 200 shown in FIGS. 5 to 7D, as shown in FIGS. 7A to 7D, the plurality of cells 22 spiral with respect to the rotation axis L in the direction extending from the first end face 31 to the second end face 32. A partition 21 is formed as shown. That is, the partition wall 21 defining the cell 22 is disposed inside the outer peripheral wall 23 having a triangular cylindrical shape in a state twisted with respect to the rotation axis L.

  For example, FIG. 7A is a plan view schematically showing the first end face 31 of the honeycomb filter 200. On the first end surface 31, lattice-like partition walls 21 that define the cells 22 are arranged so as to extend in parallel to the xy direction of the paper surface. FIG. 7B is a cross-sectional view showing a cross section perpendicular to the axial direction of the honeycomb filter in a portion having a length of 1/3 of the axial length from the first end surface 31 of the honeycomb filter 200. FIG. 7C is a cross-sectional view showing a cross section perpendicular to the axial direction of the honeycomb filter in a portion having a length that is 2/3 of the axial length from the first end surface 31 of the honeycomb filter 200. In the cross section shown in FIG. 7B, the grid-like partition walls 21 are arranged in a state of being rotated clockwise by 15 ° with respect to each of the xy directions on the paper surface. Further, in the cross section shown in FIG. 7C, the lattice-like partition walls 21 are arranged in a state of being rotated clockwise by 30 ° with respect to each of the xy directions on the paper surface.

  FIG. 7D is a plan view schematically showing the second end face 32 of the honeycomb filter 200. On the second end face 32, the grid-like partition walls 21 defining the cells 22 are arranged in a state of being rotated 45 ° clockwise relative to the xy directions on the paper surface. As described above, in the honeycomb filter 200 shown in FIGS. 5 to 7D, the rotation angle with respect to the rotation axis L from the first end surface 31 to the second end surface 32 is 45 °. The honeycomb filter 200 of the present embodiment configured as described above has the same effect as the honeycomb filter 100 shown in FIGS. 1 to 4E.

That, Ha Nikamufiruta, as long as it satisfies the configuration of the following (1) to (3), in which the same effect as the honeycomb filter 100 shown in FIGS. 1 to 4E. (1) A polygonal cylinder-shaped outer peripheral wall having a first end face and a second end face, and a plurality of cells arranged in the outer peripheral wall and having an opening on at least one end face of the first end face and the second end face A honeycomb filter provided with porous partition walls to be formed. (2) The porosity of the partition wall is 40 to 70%. (3) A plurality of cells are defined by partition walls so as to draw a spiral with respect to the rotation axis, and at least one cell located on the outer peripheral side is on the way from the first end surface to the second end surface. Be blocked by a wall. The honeycomb filter 200 shown in FIGS. 5 to 7D is configured in the same manner as the honeycomb filter 100 shown in FIGS. 1 to 4E, except that the shape of the outer peripheral wall 23 is different and the spiral rotation angle is different. . Further, the direction of rotation when the cell draws a spiral may be clockwise or counterclockwise.

  In the honeycomb filter 100 of the present embodiment as shown in FIGS. 1 to 4E, the porosity of the porous partition wall 1 is 40 to 70%. When the porosity of the partition walls is less than 40%, the exhaust gas flowing through the spiral cells 2a is difficult to permeate the partition walls 1 that form the compartments of the spiral cells 2a, and a sufficient collection performance cannot be obtained. Further, when the porosity of the partition walls is less than 40%, the pressure loss of the honeycomb filter 100 increases. On the other hand, when the porosity of the partition wall exceeds 70%, the strength of the honeycomb filter 100 is lowered. In particular, since the honeycomb filter 100 of the present embodiment is arranged in a state where the partition walls 1 are twisted with respect to the rotation axis L, the compressive strength in the axial direction is compared with a conventional honeycomb filter in which the partition walls 1 are not twisted. Tend to be low. By setting the porosity of the partition wall 1 to 70% or less, even if the partition wall 1 is arranged in a twisted state with respect to the rotation axis L, sufficient strength as a filter can be obtained. In the honeycomb filter 100 of the present embodiment, the porosity of the partition walls 1 is preferably 42 to 66%, and more preferably 45 to 61%. By comprising in this way, it can be excellent in intensity | strength, maintaining collection performance. The porosity is a value measured by a mercury porosimeter.

  In the honeycomb filter 100 shown in FIG. 1 to FIG. 4E, the central axis connecting the central points of the first end surface 11 and the second end surface 12 is the rotation axis L of the spiral trajectory of the cell 2. The rotation axis L is a virtual axis for explaining the spiral trajectory of the cell 2 in the honeycomb filter 100 of the present embodiment. The rotation axis L in the honeycomb filter 100 of the present embodiment is preferably an axis formed by connecting the first point on the first end surface 11 and the second point on the second end surface 12. Further, the rotation axis L connects a point existing inside the inscribed circle inscribed in the outer peripheral wall of the first end face 11 and a point existing in the inscribed circle inscribed in the outer peripheral wall of the second end face 12. More preferably, the shaft is formed of Further, the rotation axis L is more preferably an axis formed by connecting two points existing in the following two circles. The first circle is a circle that is concentric with an inscribed circle inscribed in the outer peripheral wall of the first end surface 11 and has a radius that is ½ of the inscribed circle. The second circle is a circle that is concentric with the inscribed circle inscribed in the outer peripheral wall of the second end face 12 and has a radius that is ½ of the inscribed circle.

  In addition, the rotation axis L is preferably an axis that is parallel to each side surface of the outer peripheral wall 3 when the outer peripheral wall 3 is the right-angle cylinder described above. By configuring in this way, some of the plurality of cells 2 can be cut-off spiral cells 2b, and the remaining cells of the plurality of cells 2 can be spiral cells 2a. In the honeycomb filter 100 of the present embodiment, the outer peripheral wall 3 is a right angle cylinder, and the rotation axis L of the spiral orbit of the cell 2 connects the center points of the first end surface 11 and the second end surface 12. It is particularly preferable that the shaft is formed.

In the honeycomb filter 100 of the present embodiment, the ratio of the number of spiral cells 2a to the total number (number) of cells 2 opened in the first end surface 11 is preferably 30 to 95%. By comprising in this way, pressure loss can be reduced, maintaining favorable collection performance. The ratio of the number of spiral cells 2a to the total number (number) of cells 2 is more preferably 45 to 90%, and particularly preferably 60 to 85%. Cells 2 other than the spiral cell 2a are blocking spiral cells 2b. If the ratio of the number of spiral cells 2a to the total number of cells 2 is less than 30%, the number of blocked spiral cells 2b may be reduced, and the collection performance may be reduced . On the other hand, when the ratio of the number of spiral cells 2a to the total number of cells 2 exceeds 95%, the pressure loss of the honeycomb filter increases .

  Moreover, in the honey-comb filter 100 whose outer peripheral wall 3 is a square cylinder shape as shown in FIGS. 1-4, the helical rotation angle from the 1st end surface 11 of the spiral cell 2a to the 2nd end surface 12 is 30. It is preferably ˜240 °. By comprising in this way, pressure loss can be reduced, maintaining favorable collection performance. When the spiral rotation angle of the spiral cell 2a is less than 30 °, the collection performance may not be sufficiently exhibited. Moreover, when the spiral rotation angle of the spiral cell 2a exceeds 240 °, the pressure loss may increase. In the case where the outer peripheral wall 3 has a rectangular tube shape, the rotation angle of the spiral of the spiral cell 2a is more preferably 60 to 150 °, and particularly preferably 60 to 90 °.

  Moreover, in the honeycomb filter 200 in which the outer peripheral wall 23 has a triangular cylindrical shape as shown in FIGS. 5 to 7D, the spiral rotation angle from the first end surface 31 to the second end surface 32 of the spiral cell 22a is 20 It is preferably ˜210 °. By comprising in this way, there exists an effect similar to the case where an outer peripheral wall is a square cylinder shape. When the outer peripheral wall 23 has a triangular cylindrical shape, the spiral rotation angle of the spiral cell 22a is more preferably 30 to 210 °, and particularly preferably 30 to 90 °.

  In the honeycomb filter 100 of the present embodiment as shown in FIGS. 1 to 4, the thickness of the partition wall 1 is not particularly limited. The thickness of the partition wall 1 is preferably 0.01 to 0.9 mm, more preferably 0.02 to 0.7 mm, and particularly preferably 0.03 to 0.6 mm. When the thickness of the partition wall 1 is less than 0.01 mm, the strength of the honeycomb filter may be lowered. When the thickness of the partition wall 1 exceeds 0.9 mm, the partition wall permeation resistance increases, the collection efficiency may not be sufficiently obtained, and the pressure loss may increase. The thickness of the partition wall 1 is a value measured by a method of observing a cross section perpendicular to the rotation axis L of the honeycomb filter 100 with a microscope.

The cell density of the honeycomb filter 100 is not particularly limited, but is preferably 20 to 100 / cm ² . If the cell density is less than 20 cells / cm ² , the strength may decrease. Further, when the cell density exceeds 100 cells / cm ² , the pressure loss may increase. The cell density is the number of cells per unit area in the first cross section of the honeycomb filter 100. The cell density is more preferably 25 to 80 cells / cm ² , and particularly preferably 30 to 50 cells / cm ² .

  There is no restriction | limiting in particular about the average pore diameter of the porous partition wall 1. FIG. The average pore diameter of the partition wall 1 is preferably 5 to 100 μm, more preferably 7 to 80 μm, and particularly preferably 9 to 50 μm. When the average pore diameter of the partition walls is less than 5 μm, the pressure loss may increase even when there is little accumulation of particulate matter on the partition walls. When the average pore diameter of the partition wall exceeds 100 μm, the partition wall 1 may become brittle and easily missing. The average pore diameter of the partition wall 1 is a value measured with a mercury porosimeter.

  The shape of the cell 2 of the honeycomb filter 100 is not particularly limited. The shape of the cell 2 in the cross section perpendicular to the axial direction of the honeycomb filter 100 is preferably a polygon such as a triangle, a quadrangle, a pentagon, a hexagon, an octagon, a circle, or an ellipse. Further, the shape of the cell 2 in the cross section may be other indefinite shape. In the honeycomb filter 100 of the present embodiment, since the cells 2 are formed so as to form a spiral in the axial direction of the honeycomb filter 100, the shape of the cells 2 in the cross section perpendicular to the axial direction is the cell on the first end surface 11. The shape of 2 may be slightly distorted. Moreover, the shape of the cell 2 in the cross section is the shape of the cell 2 when a part of the periphery of the cell 2 is not blocked by the outer peripheral wall 3.

  The porous partition wall 1 is preferably made mainly of ceramic. The material of the partition wall 1 is selected from the group consisting of silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, and aluminum titanate. At least one kind is preferred. Among these, cordierite having a small thermal expansion coefficient and excellent thermal shock resistance is preferable. “Ceramic is the main component” means that the ceramic is contained in an amount of 80% by mass or more.

  The outer peripheral wall 3 constitutes the outer peripheral portion of the honeycomb filter 100 of the present embodiment. At least one cell 2 located on the outer peripheral side of the plurality of cells 2 is blocked by the outer peripheral wall 3, and the blocked cell 2 becomes a blocked spiral cell 2b. In the honeycomb filter 100 of the present embodiment, it is preferable that the outer peripheral wall 3 has a polygonal cylindrical shape, and has a quadrangular cylindrical shape or a triangular cylindrical shape.

  The thickness of the outer peripheral wall 3 is not particularly limited. The thickness of the outer peripheral wall 3 is preferably 0.2 to 9 mm, more preferably 0.4 to 6 mm, and particularly preferably 0.6 to 2 mm. When the thickness of the outer peripheral wall 3 is thinner than 0.2 mm, the strength of the honeycomb filter 100 may be lowered. If the thickness of the outer peripheral wall 3 is greater than 9 mm, the pressure loss of the honeycomb filter 100 may increase.

  It is preferable that the outer peripheral wall 3 is mainly composed of ceramic. Specifically, the material of the outer peripheral wall 3 is silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, and aluminum titanate. It is preferably at least one selected from the group consisting of Among these, cordierite having a small thermal expansion coefficient and excellent thermal shock resistance is preferable. The material of the partition wall 1 and the outer peripheral wall 3 is preferably the same, but may be different. It is preferable that the outer peripheral wall 3 is not formed integrally with the partition wall 1 but separately disposed so as to cover the outer peripheral portion of the partition wall 1 that is twisted so as to draw a spiral. “Integrally formed” means, for example, that the partition wall 1 and the outer peripheral wall 3 are formed at the same time by a single extrusion and are continuously formed so that there is no boundary portion.

  There is no restriction | limiting in particular about the magnitude | size of the 1st end surface 11 and the 2nd end surface 12 of the outer peripheral wall 3 of a polygonal cylinder shape. In the polygonal first end face 11 and second end face 12, the length of the longest polygonal line is preferably 15 to 800 mm, more preferably 20 to 200 mm, and more preferably 30 to 60 mm. Particularly preferred.

  Here, the diameter of the inscribed circle having the same center as the rotation axis L and inscribed in the outer peripheral wall is defined as a “cylindrical inscribed diameter”. Also, the diameter of the circumscribed circle that is centered on the rotation axis L and circumscribed on the outer peripheral wall is referred to as “cylinder circumscribed diameter”. In the honeycomb structure of the present embodiment, the ratio of the “cylinder inscribed diameter” to the “cylinder inscribed diameter” is preferably 10 to 90%, and more preferably 30 to 80%. If the ratio of the “cylindrical inscribed diameter” to the “cylindrical inscribed diameter” is less than 10%, it may be difficult to form the shut-off spiral cell 2b. The pressure loss may become too large.

  The length from the first end surface 11 to the second end surface 12 of the outer peripheral wall 3 is not particularly limited. The “length from the first end surface 11 to the second end surface 12” of the outer peripheral wall 3 is hereinafter referred to as “axial length”. The axial length of the outer peripheral wall 3 can be appropriately determined according to the size of the space in which the honeycomb filter 100 is installed. The length of the outer peripheral wall 3 in the axial direction is preferably 15 to 1200 mm, more preferably 40 to 800 mm, and particularly preferably 60 to 400 mm. The axial length of the outer peripheral wall 3 affects the degree of twisting of the partition wall 1 when realizing the same spiral rotation angle. That is, when the axial length of the outer peripheral wall 3 is short, the degree of twist of the partition wall 1 increases when the same spiral rotation angle is realized. On the other hand, when the length of the outer peripheral wall 3 in the axial direction is long, the degree of twisting of the partition wall 1 becomes small when realizing the same spiral rotation angle. If the degree of twist of the partition wall 1 becomes too large, the compressive strength in the axial direction of the honeycomb filter 100 may decrease. By setting the length of the outer peripheral wall 3 in the axial direction within the above numerical range, the honeycomb filter 100 can be made compact and has high compressive strength in the axial direction.

(2) Manufacturing method of honeycomb filter:
Next, a method for producing the Ha Nikamufiruta, how the outer peripheral wall, as shown in FIGS. 1 to 4 to manufacture a honeycomb filter of a square tube shape as an example.

  When manufacturing the honeycomb filter of the present embodiment, first, a honeycomb structure 500 as shown in FIGS. 8 and 9 is manufactured. A honeycomb structure 500 shown in FIGS. 8 and 9 includes a partition wall 501 that partitions and forms a plurality of cells 502 extending from one end surface 511 to the other end surface 512, and an outer peripheral wall 543 disposed so as to surround the partition wall 501. I have it. The honeycomb structure 500 has a cylindrical shape. In this honeycomb structure 500, a plurality of cells 502 are partitioned by partition walls 501 so as to draw a spiral with respect to a rotation axis extending in a direction extending from one end surface 511 to the other end surface 512.

  By grinding the outer peripheral portion of such a honeycomb structure 500 to obtain a prismatic structure, and by arranging the outer peripheral wall again on the side surface of the obtained prismatic structure, A honeycomb filter can be manufactured. A broken line J in FIGS. 8 and 9 indicates a position (grinding position) where the honeycomb structure 500 is ground.

  The honeycomb structure 500 shown in FIGS. 8 and 9 can be manufactured as follows. First, a forming raw material containing a ceramic raw material is mixed and kneaded to obtain a clay. The ceramic raw material is at least one selected from the group consisting of silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, and aluminum titanate. Is preferably used. The cordierite forming raw material is a ceramic raw material blended so as to have a chemical composition that falls within the range of 42 to 56% by mass of silica, 30 to 45% by mass of alumina, and 12 to 16% by mass of magnesia. The cordierite forming raw material is fired to become cordierite.

  The forming raw material is preferably prepared by further mixing the ceramic raw material with a dispersion medium, an organic binder, an inorganic binder, a surfactant, a pore former, and the like. The composition ratio of each raw material is not particularly limited, and is preferably a composition ratio in accordance with the structure and material of the honeycomb structure to be manufactured.

  Water can be used as the dispersion medium. It is preferable that the addition amount of a dispersion medium is 10-30 mass parts with respect to 100 mass parts of ceramic raw materials.

  The organic binder is preferably methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, or a combination thereof. Moreover, the addition amount of the organic binder is preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the ceramic raw material.

  As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type and may be used in combination of 2 or more type. The addition amount of the surfactant is preferably 0.5 to 2 parts by mass with respect to 100 parts by mass of the ceramic raw material.

  As the pore former, resin particles, starch, carbon and the like can be used. The pore former is for forming pores in the partition walls of the honeycomb structure to be manufactured. It is preferable to adjust the addition amount of the pore former so that the partition walls of the honeycomb structure are 40 to 70%. If the porosity of the partition walls of the obtained honeycomb structure can be made 40 to 70% without adding the pore former, it is not necessary to add the pore former.

  There is no restriction | limiting in particular as a method of kneading | mixing a shaping | molding raw material and forming a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  Next, the obtained clay is formed to form a cylindrical honeycomb formed body. The honeycomb formed body has partition walls that partition and form a plurality of cells. A method for forming a kneaded clay to form a honeycomb formed body is not particularly limited, and a known forming method such as extrusion molding or injection molding can be used. For example, a preferable example includes a method of extrusion molding using a die for extrusion molding having a desired cell shape, partition wall thickness, and cell density. As a material of the die for extrusion molding, a cemented carbide which does not easily wear is preferable.

  When forming a honeycomb formed body, it is preferable to apply a helical twist to the obtained honeycomb formed body by extruding the kneaded material while rotating the extrusion forming die described above. At this time, it is preferable that the tip portion of the extruded honeycomb molded body is received by a cradle or the like so that the extruded portion does not rotate in synchronization with the rotation of the extrusion molding die. Accordingly, a honeycomb formed body can be obtained by partitioning the plurality of cells so as to draw a spiral with respect to the rotation axis extending in the direction from one end face to the other end face.

  By adjusting the rotation speed of the extrusion molding die and the extrusion speed of the clay, the helical rotation angle in the honeycomb molded body can be adjusted.

  Alternatively, the obtained honeycomb formed body may be twisted after obtaining a honeycomb formed body in which cells extending from one end face to the other end face are formed without rotating the extrusion forming die. That is, a twisted honeycomb formed body is prepared by twisting the obtained honeycomb formed body so that a plurality of cells draw a spiral with the direction extending from one end face to the other end face as a rotation axis. May be.

  Next, the obtained honeycomb formed body is dried. Next, the dried honeycomb formed body is fired. As a result, a honeycomb structure 500 including porous partition walls 501 for partitioning a plurality of cells 502 serving as fluid flow paths as shown in FIGS. 8 and 9 can be obtained. In this honeycomb structure 500, all the cells 502 are partitioned by partition walls 501 so as to draw a spiral from one end surface 511 to the other end surface 512. That is, in the honeycomb structure 500, all the cells 502 are “spiral cells”.

  Examples of the drying method include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, and the like. Among them, it is preferable to perform dielectric drying, microwave drying, or hot air drying alone or in combination.

  Prior to firing the honeycomb formed body, the honeycomb formed body is preferably calcined. Calcination is performed for degreasing. There is no particular limitation on the method of calcination. For example, it is sufficient that at least a part of the organic matter in the honeycomb formed body can be removed. Examples of the organic material include an organic binder, a surfactant, and a pore former. The combustion temperature of the organic binder is about 100 to 300 ° C. For this reason, calcination is preferably performed at about 200 to 1000 ° C. for about 10 to 100 hours in an oxidizing atmosphere.

  The firing of the honeycomb formed body is performed in order to sinter and densify the forming raw material constituting the calcined formed body to ensure a predetermined strength. Since the firing conditions differ depending on the type of molding raw material, appropriate conditions may be selected according to the type. For example, when the cordierite forming raw material is used, the firing temperature is preferably 1350 to 1440 ° C. In addition, the firing time is preferably 3 to 10 hours as the keep time at the maximum temperature. Examples of the apparatus for performing calcination and main firing include an electric furnace and a gas furnace.

  Next, the outer peripheral portion of the obtained honeycomb structure 500 is ground to obtain a prismatic structure (a prismatic structure 600).

  Next, as shown in FIG. 10, an outer peripheral wall 703 is disposed on the outer periphery of the obtained prismatic structure 600, thereby manufacturing a honeycomb filter 700 having an outer peripheral wall of a rectangular tube shape. The prismatic structure 600 has a porous partition wall 701, and a plurality of cells 702 are partitioned by the partition wall 701. In the honeycomb filter 700 shown in FIG. 10, the plurality of cells 702 are partitioned by the partition 701 so as to draw a spiral with respect to the rotation axis in the direction extending from the first end surface 711 to the second end surface 712.

  In the honeycomb filter 700 shown in FIG. 10, at least one cell 702 located on the outer peripheral side of the plurality of cells 702 is blocked by the outer peripheral wall 703 on the way from the first end surface 711 to the second end surface 712. Yes. That is, by grinding the honeycomb structure 500 shown in FIGS. 8 and 9, at least one cell 502 located on the outer peripheral side of the obtained prismatic structure 600 is cut off in the middle of the spiral trajectory. . Then, by newly disposing the outer peripheral wall 703 on the outer peripheral side of the prismatic structure 600, the cell 702 cut off in the middle of the spiral trajectory is blocked by the outer peripheral wall 703.

  Examples of a method of forming the outer peripheral wall 703 include a method of applying a slurry-like coating material to the outer periphery of the prismatic structure 600 and drying the applied coating material. After the coating material is dried, it may be further baked. Examples of such a coating material include those having the same components as the clay for producing a honeycomb structure. The coating material may be a cement coating material using ceramic cement or the like.

  As described above, the honeycomb filter of the present embodiment can be manufactured. 8 and 9 show an example in which the honeycomb structure 500 has a cylindrical shape. However, the honeycomb structure 500 has a shape that allows twisting of the green body before firing so that the plurality of cells 502 draw a spiral. Any shape other than a cylindrical shape may be used. That is, if the honeycomb structure can twist the formed body before firing and grind the outer peripheral portion of the obtained honeycomb structure to obtain a prismatic prismatic structure, There is no particular limitation on the shape of the honeycomb structure. In addition, since it is easy to apply a uniform twist to the rotating shaft when twisting the formed body, the honeycomb structure 500 is preferably cylindrical.

  8 and 9 show an example in which the shape of the prismatic structure 600 is a quadrangular prism, but other polygonal prisms such as a triangular prism may be used. When the number of corners of the end face in the polygonal column increases, the shape of the prismatic structure 600 becomes close to a cylinder. When the shape of the prismatic structure 600 is close to a cylinder, the cell 502 on the outer peripheral side of the prismatic structure 600 may not be easily cut off. For this reason, it is preferable that the shape of the prismatic structure 600 is a triangular prism or a quadrangular prism.

(3) Joined honeycomb filter:
Next, an embodiment of the bonded honeycomb filter of the present invention will be described. Joined type honeycomb filter of the present embodiment is provided with a plurality of Ha Nikamufiruta described so far. Here, the bonded honeycomb filter of the present embodiment will be described by taking as an example a bonded honeycomb filter including a plurality of honeycomb filters 100 shown in FIGS. FIG. 11 is a perspective view schematically showing one embodiment of a bonded honeycomb filter of the present invention.

As shown in FIG. 11, joined type honeycomb filter 800 of the present embodiment is provided with a plurality of wafer Nikamufiruta 100 described so far. In the bonded honeycomb filter 800 of the present embodiment, a plurality of honeycomb filters 100 are bonded in a state of being arranged adjacent to each other so that the surfaces of the outer peripheral walls 3 face each other. When viewed from the first end face 11 side, the bonded honeycomb filter 800 shown in FIG. 11 has a total of 9 honeycomb filters 100 bonded, 3 each in length and width. The surfaces of the outer peripheral walls 3 of the honeycomb filter 100 are bonded together by a bonding layer 811.

  The bonding layer 811 is preferably formed of a bonding material for bonding the surfaces of the outer peripheral walls 3 of the honeycomb filter 100 to each other. Examples of the bonding material include those prepared by dispersing fillers such as inorganic fibers, colloidal silica, clay, SiC particles, organic binders, and foamed resins in a dispersion medium such as water. Such a bonding material is applied to the surface (that is, the bonding surface) of the outer peripheral wall 3 of the honeycomb filter 100, and the surface of the outer peripheral surface 3 of another honeycomb filter 100 is applied to the surface on which the bonding material is applied. The surfaces of the outer peripheral walls 3 are joined to each other. A material obtained by drying and solidifying the bonding material becomes the bonding layer 811 described above.

  There is no particular limitation on the thickness of the bonding layer. The thickness of the bonding layer is preferably 0.1 to 9 mm, more preferably 0.2 to 5 mm, and particularly preferably 0.4 to 3 mm. “Thickness of the bonding layer” refers to the bonding type honeycomb filter bonded from the surface (bonding surface) of the outer peripheral wall of one honeycomb filter in the cross section perpendicular to the axial direction of the honeycomb filter via the bonding layer. It means the length to the surface (joint surface) of the outer peripheral wall of the honeycomb filter. When the thickness of the bonding layer is too thick, the area through which the exhaust gas passes in the cross section perpendicular to the axial direction of the honeycomb filter of the bonded honeycomb filter may be relatively small, and the pressure loss may increase. If the thickness of the bonding layer is too thin, the bonding force for bonding the honeycomb filters may not be sufficiently obtained. In addition, by arranging the bonding layer between the honeycomb filters, the volume change can be buffered by the bonding layer when each honeycomb filter is thermally expanded or contracted. If the thickness of the bonding layer is too thin, the above-described effect of buffering the volume change may not be sufficiently exhibited.

In the bonded honeycomb filter 800 of the present embodiment, each honeycomb filter 100 to be bonded is provided with the outer peripheral wall 3 having a polygonal cylindrical shape in advance, so that the bonding of the honeycomb filter 100 by the bonding layer 811 is extremely easy. Joined type honeycomb filter 800 of the present embodiment is obtained by a plurality bonded Ha Nikamufiruta, in which the same effects as Ha Nikamufiruta.

  In FIG. 11, nine honeycomb filters 100 are joined by the joining layer 811, but the number of honeycomb filters 100 to be joined is not particularly limited. Depending on the size of the bonded honeycomb filter 800 and the size of the honeycomb filter 100, the number of the honeycomb filters 100 to be bonded can be appropriately determined.

  The bonded honeycomb filter may further include an outer wall disposed so as to cover the side surfaces subjected to grinding by grinding the outer peripheral portions of the plurality of bonded honeycomb filters. FIG. 12 is a perspective view schematically showing another embodiment of the bonded honeycomb filter of the present invention.

  A bonded honeycomb filter 801 shown in FIG. 12 is obtained by grinding an outer peripheral portion of a bonded honeycomb filter 800 as shown in FIG. 11 and further arranging an outer wall 810 so as to cover the ground side surface. . By comprising in this way, the whole shape of the joining type honeycomb filter 801 can be made into a desired shape. Since each honeycomb filter 100 constituting the bonded honeycomb filter 801 includes the outer peripheral wall 3 having a polygonal cylindrical shape, a bonded honeycomb filter 800 (see FIG. 11) in which a plurality of honeycomb filters 100 are bonded is as follows. The overall shape is a polygonal cylindrical shape. After the honeycomb filter 100 is bonded by the bonding layer 811, the outer peripheral portion thereof is ground and further provided with the outer wall 810, so that the bonded honeycomb filter 801 is desired while maintaining the effects expressed by the individual honeycomb filters 100. It can be made into the shape.

  The outer wall 810 of the bonded honeycomb filter 801 is preferably formed using the same material as the outer peripheral wall 3 of each honeycomb filter 100.

  In addition, the bonded honeycomb filter may be a honeycomb filter provided with an outer peripheral wall having a polygonal cylindrical shape other than the rectangular cylindrical shape, bonded by a bonding layer. FIG. 13 is a perspective view schematically showing still another embodiment of the bonded honeycomb filter of the present invention. A bonded honeycomb filter 802 illustrated in FIG. 13 is obtained by bonding the honeycomb filter 200 including the outer peripheral wall 23 having a triangular cylindrical shape illustrated in FIGS. In the bonded honeycomb filter 802 shown in FIG. 13, six honeycomb filters 200 are bonded by a bonding layer 811. In the bonded honeycomb filter 802 shown in FIG. 13, the outer peripheral portion of the bonded honeycomb filter 802 is not ground, and the outer periphery of the bonded honeycomb filter 802 is constituted by the outer peripheral wall 23 of the honeycomb filter 200. Also in the bonded honeycomb filter 802 shown in FIG. 13, the outer peripheral portion thereof may be ground to further dispose an outer wall 810 as shown in FIG. 12.

  Further, the honeycomb filters constituting the bonded honeycomb filter may have the same outer peripheral shape or may have different outer peripheral shapes. In other words, the bonded honeycomb filter of the present invention may include a plurality of honeycomb filters having different outer peripheral shapes, and these honeycomb filters may be bonded by the bonding layer.

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

Example 1
First, a kneaded material for forming a honeycomb formed body was prepared using a forming raw material containing a ceramic raw material. As a ceramic raw material, a cordierite forming raw material was used. A clay for molding was prepared by adding a dispersion medium, an organic binder, a dispersant and a pore former to the cordierite forming raw material. The addition amount of the dispersion medium was 3 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The addition amount of the organic binder was 5 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The addition amount of the pore former was 10 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The obtained ceramic forming raw material was kneaded using a kneader to obtain clay.

As cordierite-forming material, talc, kaolin, alumina, silica, MgO 13.5 wt%, _Al 2 _{O 3} is 36.0 wt%, SiO ₂ was prepared to have the composition of 50.5 wt% .

  Next, the obtained kneaded material was extruded using a vacuum extrusion molding machine to obtain a honeycomb formed body. When forming the honeycomb formed body, the extrusion was performed while rotating the extrusion forming die of the vacuum extrusion molding machine on the surface perpendicular to the extrusion direction of the clay. The tip portion of the extruded honeycomb formed body was received by a cradle so that the extruded portion did not rotate in synchronization with the rotation of the extrusion die.

  In Example 1, the extrusion molding of the vacuum extrusion molding machine was rotated so that the spiral rotation angle of the obtained honeycomb filter was 15 °. The shape of the honeycomb formed body was a cylindrical shape, and the diameter of the end face was 70 mm.

  Next, the obtained honeycomb formed body was dried by high frequency dielectric heating, and then dried at 120 ° C. for 2 hours using a hot air dryer. Then, it fired at 1350-1450 degreeC for 10 hours, and obtained the honeycomb structure.

In the obtained honeycomb structure, the partition wall thickness at one end face was 0.3 mm, and the cell density was 40 cells / cm ² . Further, the length from one end face of the honeycomb structure to the other end face was 150 mm. The porosity of the partition walls of the honeycomb structure was 60%. The porosity is a value measured by a mercury porosimeter.

  The outer peripheral portion of the obtained honeycomb structure was ground to produce a prismatic structure having a square end face. The prismatic structure is ground so that one end face and the other end face of the honeycomb structure are square. The prismatic structure has a regular quadrangular prism shape with one side of a square end face being 50 mm.

  A slurry-like coating material was applied to the outer peripheral surface of the obtained prismatic structure. The coating material applied to the outer peripheral surface of the prismatic structure was dried to prepare the outer peripheral wall. The thickness of the outer peripheral wall was 3 mm. Thus, the honeycomb filter of Example 1 was produced. The spiral rotation angle of the honeycomb filter of Example 1 is 30 °. Table 1 shows “shape of outer peripheral wall”, “spiral rotation angle (°)”, and “porosity (%)” of the honeycomb filter of Example 1.

  The honeycomb filter of Example 1 was evaluated for “collecting performance”, “pressure loss”, “strength”, and [ash deposition] by the following methods. The results are shown in Table 1.

[Capture performance]
The honeycomb filter of Example 1 was mounted on an exhaust system of a diesel engine, and the collection performance was measured. About the measurement result, it evaluated in five steps of A, B, C, Y, and Z. The case where the collection efficiency was 30% or more and less than 50% was evaluated as A. The case where the collection efficiency was 15% or more and less than 30% was evaluated as B. The case where the collection efficiency was 10% or more and less than 15% was evaluated as C. A case where the collection efficiency was 70% or more was evaluated as Y. The case where the collection efficiency was 0% or more and less than 10% was evaluated as Z.

[Pressure loss]
The honeycomb filter of Example 1 was mounted on an exhaust system of a diesel engine, and pressure loss was measured. About the measurement result, it evaluated in four steps of A, B, C, and Z. The measured pressure loss value is equivalent to the pressure loss of Comparative Example 3 (specifically, from the value of 20% decrease in the pressure loss value of Comparative Example 3, the pressure loss value of Comparative Example 3). The case of up to a value of 20% increase in value) was designated as evaluation A. A case where the measured pressure loss value was an increase of 30% or more and less than 60% with respect to the pressure loss value of Comparative Example 3 was evaluated as B. Evaluation C was defined when the measured pressure loss value was an increase of 60% or more and less than 200% with respect to the pressure loss value of Comparative Example 3. The case where the measured pressure loss value was an increase of 200% or more with respect to the pressure loss value of Comparative Example 3 was evaluated as Z.

[Strength]
The strength of the honeycomb filter of Example 1 was measured using a compression tester. About the measurement result, it evaluated in four steps of A, B, C, and Z. Compared to the strength of Comparative Example 3, the case of the same (specifically, from the value of 15% decrease in strength of Comparative Example 3 to the value of 15% increase in strength of Comparative Example 3) did. The case where the measured intensity value was a decrease of more than 15% and not more than 35% with respect to the intensity value of Comparative Example 3 was defined as evaluation B. A case where the measured intensity value was a decrease of more than 35% and not more than 60% with respect to the intensity value of Comparative Example 3 was evaluated as C. The case where the measured intensity value was a decrease of more than 60% with respect to the intensity value of Comparative Example 3 was defined as evaluation Z.

[Ash deposition]
The honeycomb filter of Example 1 was mounted on an exhaust system of a diesel engine, and a running test equivalent to 100,000 km was performed to measure the ash accumulation mass. About the measurement result, it evaluated in four steps of A, B, C, Y, and Z. A case where ash of 0% by mass or more and less than 20% by mass was deposited with respect to the total amount of ash flowing into the honeycomb filter was evaluated as A. Evaluation B was defined as a case where 20% by mass or more and less than 40% by mass of ash was deposited with respect to the total amount of ash flowing into the honeycomb filter. Evaluation C was defined as 40% by mass or more and less than 60% by mass of ash deposited on the total amount of ash flowing into the honeycomb filter. The case where 60 mass% or more of ash was deposited with respect to the total amount of ash flowing into the honeycomb filter was evaluated as Z.

(Examples 2 to 9, Comparative Examples 1 and 2)
A honeycomb filter was manufactured in the same manner as in Example 1 except that the spiral rotation angle and the porosity of the partition walls were changed to those shown in Table 1. With respect to the obtained honeycomb filter, evaluation of “capturing performance”, “pressure loss”, “strength”, and [ash deposition] was performed in the same manner as in Example 1. The results are shown in Table 1. Moreover, the change of the spiral rotation angle was performed by adjusting the rotation speed of the die for extrusion molding of the vacuum extrusion molding machine. Further, the porosity of each partition wall was adjusted by the amount of pore former added.

(Comparative Example 3)
A honeycomb molded body in which cells extend straight from one end surface to the other end surface without rotating the extrusion molding die of the vacuum extrusion molding machine is prepared. Produced. With respect to the obtained honeycomb filter, evaluation of “capturing performance”, “pressure loss”, “strength”, and [ash deposition] was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
A honeycomb molded body in which cells extend straight from one end surface to the other end surface without rotating the extrusion molding die of the vacuum extrusion molding machine is prepared. Produced. In Comparative Example 4, a plugging member was disposed in an opening portion on one end face of each cell of the honeycomb filter. That is, a plugging member was disposed in the opening portion of the first end surface of a predetermined cell and the opening portion of the second end surface of the remaining cell, thereby manufacturing a honeycomb filter. With respect to the obtained honeycomb filter, evaluation of “capturing performance”, “pressure loss”, “strength”, and [ash deposition] was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 10)
In Example 10, a honeycomb filter having an outer peripheral wall with a triangular tube shape was manufactured. First, a honeycomb structure was produced by the same method as in Example 1. The outer peripheral portion of the obtained honeycomb structure was ground to produce a prismatic structure having a triangular end surface. The prismatic structure is ground so that one end face and the other end face of the honeycomb structure are triangular. The prismatic structure has a regular triangular prism shape with one side of a triangular end face of 45 mm.

  The coating material of the same material as what was applied to the outer peripheral surface of the prismatic structure of Example 1 was applied to the obtained prismatic structure. The coating material applied to the outer peripheral surface of the prismatic structure was dried to prepare the outer peripheral wall. The thickness of the outer peripheral wall was 40 mm. Thus, the honeycomb filter of Example 10 was produced. The spiral rotation angle of the honeycomb filter of Example 10 is 15 °. Table 2 shows “the shape of the outer peripheral wall”, “helical rotation angle (°)”, and “porosity (%)” of the honeycomb filter of Example 10.

  In addition, evaluation of “capturing performance”, “pressure loss”, “strength”, and [ash deposition] was performed in the same manner as in Example 1. The results are shown in Table 2.

(Examples 11 to 18, Comparative Examples 5 and 6)
A honeycomb filter was manufactured in the same manner as in Example 10 except that the spiral rotation angle and the porosity of the partition walls were as shown in Table 2. With respect to the obtained honeycomb filter, evaluation of “capturing performance”, “pressure loss”, “strength”, and [ash deposition] was performed in the same manner as in Example 1. The results are shown in Table 2. Moreover, the change of the spiral rotation angle was performed by adjusting the rotation speed of the die for extrusion molding of the vacuum extrusion molding machine. Further, the porosity of each partition wall was adjusted by the amount of pore former added.

(Comparative Example 7)
A honeycomb molded body in which the cells extend straight from one end surface to the other end surface without rotating the extrusion molding die of the vacuum extrusion molding machine is prepared. Produced. With respect to the obtained honeycomb filter, evaluation of “capturing performance”, “pressure loss”, “strength”, and [ash deposition] was performed in the same manner as in Example 1. The results are shown in Table 2.

(result)
As shown in Table 1 and Table 2, the honeycomb filters of Examples 1 to 18 were excellent in collection performance and low in pressure loss. In the honeycomb filters of Comparative Examples 3 and 7, since the cells partitioned by the partition walls extend straight from one end surface toward the other end surface, the collection performance was extremely poor. Therefore, Comparative Examples 3 and 7 were not used as filters.

  Further, in the honeycomb filters of Comparative Examples 1 and 5, the partition walls have a low porosity, so that the exhaust gas flowing into the spiral cells hardly passes through the partition walls that define the outside of the spiral cells, and the trapping performance is poor. It was. Moreover, since the exhaust gas hardly passes through the partition walls, the pressure loss has also increased. In addition, the honeycomb filters of Comparative Examples 2 and 6 had extremely low honeycomb filter strength because the partition wall porosity was too high.

  In addition, among Examples 1 to 9, the balance between the collection performance and the pressure loss was particularly good in Examples 2 to 6 in which the spiral rotation angle was 30 to 240 °. That is, when the shape of the outer peripheral wall is a square tube shape, it has been found that the spiral rotation angle is preferably 30 to 240 °. Further, among the honeycomb filters of Examples 10 to 18, Examples 11 to 15 having a spiral rotation angle of 20 to 210 ° had a particularly good balance between the collection performance and the pressure loss. That is, when the shape of the outer peripheral wall is a triangular tube shape, it has been found that the spiral rotation angle is preferably 20 to 210 °.

The bonded honeycomb filter of the present invention can be suitably used as a filter for purifying gas exhausted from an internal combustion engine, various combustion devices, and the like.

1, 2: 1 Partition, 2, 22: Cell, 2a: Cell (spiral cell), 2b: Cell (blocking spiral cell), 2p, 2q, 2r, 2s, 2t, 2u: Cell, 3, 23 outer peripheral wall, 11 , 31: first end face, 12, 32: second end face, 100, 200: honeycomb filter, 500: honeycomb structure, 501: partition wall, 502: cell, 511: one end face, 512: other end face, 543: Outer peripheral wall, 600: prismatic structure, 700: honeycomb filter, 800, 801, 802: bonding side honeycomb filter, 810: outer wall, 811: bonding layer, L: rotating shaft, J: grinding position.

Claims (5)

A polygonal cylinder-shaped outer peripheral wall having a first end surface and a second end surface, and a plurality of cells arranged inside the outer peripheral wall and having an opening on at least one end surface of the first end surface and the second end surface A porous partition wall to be formed,
The partition wall has a porosity of 40 to 70%,
A plurality of the cells are defined by the partition so as to form a spiral with respect to a rotation axis extending from the first end surface to the second end surface; and
At least one cell located on the outer peripheral side of the plurality of cells includes a plurality of honeycomb filters that are blocked by the outer peripheral wall in the middle from the first end surface to the second end surface ,
A joined honeycomb filter in which the plurality of honeycomb filters are joined in a state of being arranged adjacent to each other so that surfaces of the outer peripheral walls face each other. The bonded honeycomb filter according to claim 1, wherein the outer peripheral wall has a quadrangular cylindrical shape or a triangular cylindrical shape. The outer peripheral wall is a rectangular tube shape,
The rotation angle of the cell formed so as to draw a spiral from the first end surface to the second end surface with respect to the rotation axis from the first end surface to the second end surface is 30 to 240 °. The bonded honeycomb filter as described. The outer peripheral wall has a triangular tube shape,
The rotation angle with respect to the said rotating shaft from the said 1st end surface to the said 2nd end surface of the cell formed so that a spiral may be drawn from the said 1st end surface to the said 2nd end surface is 20-210 degrees. The bonded honeycomb filter as described. The bonded honeycomb filter according to claim 4 , further comprising an outer wall disposed so as to cover an outer peripheral portion of the plurality of bonded honeycomb filters that are ground and cover the ground side surfaces.

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