Inspection device and inspection method for columnar honeycomb filters

Abstract

To provide a device for inspecting a columnar honeycomb filter, having high inspection accuracy of collection performance and allowing downsizing.SOLUTION: A device 100 for inspecting a columnar honeycomb filter 1 includes: a storage part 10 capable of storing the columnar honeycomb filter; an introduction pipe 20 and an exhaust pipe 30 capable of circulating gas and connected to the storage part 10; a particle generator 40 for generating particles; a particle introduction part 50 for introducing the particles generated in the particle generator 40 into the introduction pipe 20; a gas agitation part 60 placed in the introduction pipe 20 on the upstream side of the particle introduction part 50 in a gas flow direction X; a particle concentration controller 70 placed in the introduction pipe 20 on the downstream side of the particle introduction part 50 in the gas flow direction X; and particle counters 80a and 80b placed in the introduction pipe 20 and the exhaust pipe 30 on the downstream side of the particle concentration controller 70 in the gas flow direction X and measuring the number of the particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inspection device and an inspection method for a columnar honeycomb filter. [Background technology]

[0002] Exhaust gas emitted from internal combustion engines such as diesel and gasoline engines contains particulate matter (hereinafter referred to as PM) such as soot. PM such as soot is harmful to the human body, and its emission is regulated. Currently, in order to comply with exhaust gas regulations, filters such as diesel particulate filters (DPFs) and gasoline particulate filters (GPFs) are widely used, which filter out PM such as soot by passing exhaust gas through porous partition walls.

[0003] A known filter for capturing PM such as soot is a wall-flow type columnar honeycomb structure (hereinafter also referred to as a "columnar honeycomb filter") that has partition walls that define a plurality of first cells and second cells extending from a first end face to a second end face, the first cells and the second cells being adjacently arranged with the partition walls in between, the first end faces of the first cells and the second end faces of the second cells being open, and plugging portions being provided on the second end faces of the first cells and the first end faces of the second cells.

[0004] In recent years, with the strengthening of exhaust gas regulations, stricter PM emission standards (PN regulations: Particulate Matter number regulations) have been introduced, and there is a demand for improved inspection accuracy of filters' PM collection performance (PN collection efficiency). A known conventional inspection method is to supply soot particles with a median diameter of 300 nm to a filter, measure the number of soot particles before and after supplying them to the filter using a particle counter, and calculate the difference (Patent Document 1). Another known method is to supply a gas containing fine particles to a first end face of a columnar honeycomb filter, irradiate the second end face with a sheet-like light parallel to the second end face so as to cover the entire second end face, and capture an image of the entire second end face using a camera (Patent Document 2).

[0005] However, with the inspection method of Patent Document 1, the amount of soot particles supplied tends to vary depending on the location within the filter. This is because the inspection method of Patent Document 1 makes it difficult to agitate the soot particles, resulting in a biased concentration distribution of soot particles in a plane perpendicular to the soot particle supply direction. Therefore, even when inspecting the same product, variations in measurement values ​​occur depending on the orientation and installation of the filter, reducing the inspection accuracy of the filtering performance. Furthermore, the inspection method of Patent Document 2 simply evaluates differences in brightness on the image based on the scattering of sheet-like light when it hits fine particles, and therefore does not provide sufficient inspection accuracy for filtering performance.

[0006] Therefore, in Patent Document 3, the present applicant proposed an inspection device for a columnar honeycomb filter, the inspection device comprising: a storage section capable of storing a columnar honeycomb filter; an inlet pipe and an outlet pipe through which gas can flow and which are connected to the storage section; a particle generating section that generates particles; a particle introducing section that introduces the particles generated in the particle generating section into the inlet pipe; a gas agitating section that is installed in the inlet pipe upstream of the particle introducing section in the gas flow direction; and particle measuring devices that are installed in the inlet pipe and the outlet pipe downstream of the particle introducing section in the gas flow direction. This inspection device effectively agitates particles using the gas agitating section installed in a predetermined position, thereby suppressing bias in the particle concentration distribution in a plane perpendicular to the gas flow direction, thereby improving the inspection accuracy of the collection performance. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US Patent Application Publication No. 2020 / 0254435 [Patent Document 2] Patent No. 6756939 [Patent Document 3] Patent No. 7022241 Summary of the Invention [Problem to be solved by the invention]

[0008] In the inspection device described in Patent Document 3, when the diameter of the columnar honeycomb filter to be inspected is large, the diameter of the inlet pipe connected to the housing portion in which the columnar honeycomb filter is housed must also be large. However, if the diameter of the inlet pipe is increased, the inlet pipe must be made longer in order to suppress bias in the particle concentration distribution in a plane perpendicular to the gas flow direction, which poses a problem of increasing the size of the inspection device. Furthermore, even if the diameter of the columnar honeycomb filter is not large, the inspection device for the columnar honeycomb filter is relatively large (for example, the introduction pipe is long), and therefore the installation space is currently limited.

[0009] The present invention has been made to solve the above problems, and has an object to provide a columnar honeycomb filter inspection device that has high accuracy in inspecting filtering performance and can be made compact. Another object of the present invention is to provide a columnar honeycomb filter inspection method that has high accuracy in inspecting filtering performance and can be performed in a compact environment. [Means for solving the problem]

[0010] The inventors discovered that by providing a particle concentration adjustment section in addition to a gas agitation section at a predetermined position in a columnar honeycomb filter inspection device, it is possible to suppress bias in the particle concentration distribution in a plane perpendicular to the gas flow direction without having to lengthen the inlet pipe, thereby improving the inspection accuracy of the collection performance, and thus completed the present invention. That is, the present invention is exemplified as follows.

[0011] [1] A housing portion capable of housing a columnar honeycomb filter; an inlet pipe and an outlet pipe through which a gas can flow and which are connected to the storage section; a particle generating unit that generates particles; a particle introduction section that introduces the particles generated in the particle generation section into the introduction pipe; a gas agitator disposed in the gas inlet pipe upstream of the particle inlet in the gas flow direction; a particle concentration adjusting unit disposed in the inlet pipe downstream of the particle introducing unit in the gas flow direction; a particle counter that is installed in the inlet pipe and the outlet pipe downstream of the particle concentration adjusting unit in the gas flow direction and that measures the number of particles; Equipped with 、 The gas agitation unit is a gas agitation plate having a pair of flat surfaces perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of flat surfaces, and the plurality of openings of the gas agitation plate are provided in a region from the outer periphery of the flat surfaces to 1 / 2 of the diameter of the flat surfaces, The particle concentration adjustment unit is a particle concentration adjustment plate having a pair of flat surfaces perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of flat surfaces, and the plurality of openings of the particle concentration adjustment plate are provided in an area extending from the center of the flat surfaces to 4 / 5 of the diameter of the flat surfaces. ,Inspection equipment for columnar honeycomb filters.

[0014] [ 2 The particle concentration adjustment plate has an opening ratio of 30% or more. [1] An inspection device for the pillar-shaped honeycomb filter according to claim 1.

[0015] [ 3 The diameter of the opening of the particle concentration adjustment plate is 10,000 to 200,000 times the average particle size of the particles. [1] or [2] An inspection device for the pillar-shaped honeycomb filter according to claim 1.

[0016] [ 4 ] The distance between the downstream end of the introduction pipe and the particle introduction part in the gas flow direction is 5 to 10 times the diameter of the introduction pipe, [1] to [ 3 ] The inspection device for a pillar-shaped honeycomb filter according to any one of the above.

[0017] [ 5 ] The diameter of the introduction pipe is 150 to 270 mm, [1] to [ 4 ] The inspection device for a pillar-shaped honeycomb filter according to any one of the above.

[0018] [ 6 ] the distance between the downstream end of the introduction pipe and the particle introduction part in the gas flow direction is 1400 to 2600 mm, [1] to [ 5 ] The inspection device for a pillar-shaped honeycomb filter according to any one of the above.

[0019] [ 7 ] The diameter of the columnar honeycomb filter is 90 to 356 mm, [1] to [ 6] The inspection device for a pillar-shaped honeycomb filter according to any one of the above.

[0021] [ 8 The gas stirring plate has an opening ratio of 5 to 50%. One of [1] to [7] An inspection device for the pillar-shaped honeycomb filter according to claim 1.

[0022] [ 9 ] Further comprising a calculation unit that calculates the particle collection efficiency based on the number of particles measured by the particle measuring instruments installed in the inlet pipe and the outlet pipe, [1] to [ 8 ] The inspection device for a pillar-shaped honeycomb filter according to any one of the above.

[0023] [ 10 ] the particles are one or more selected from soot particles, carbon particles, oil particles, NaCl particles, and resin particles, [1] to [ 9 ] The inspection device for a pillar-shaped honeycomb filter according to any one of the above.

[0024] [ 11 a particle generating step of generating particles; a particle introducing step of introducing the particles generated in the particle generating step into the gas stirred by the gas stirring unit; The concentration of particles in the gas is By particle concentration adjustment unit a particle concentration adjusting step of adjusting the particle concentration; a particle supplying step of supplying the gas having the particle concentration adjusted to a columnar honeycomb filter; a particle measuring step of measuring the number of particles in the gas on the upstream side and downstream side of the columnar honeycomb filter in the gas flow direction; Including fruit, The gas agitation unit is a gas agitation plate having a pair of flat surfaces perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of flat surfaces, and the plurality of openings of the gas agitation plate are provided in a region from the outer periphery of the flat surfaces to 1 / 2 of the diameter of the flat surfaces, the particle concentration adjustment unit is a particle concentration adjustment plate having a pair of flat surfaces perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of flat surfaces, and the plurality of openings of the particle concentration adjustment plate are provided in an area extending from the center of the flat surfaces to 4 / 5 of a diameter of the flat surfaces. Inspection method for columnar honeycomb filters.

[0027] [ 12 The particle concentration adjustment plate has an opening ratio of 30% or more.

[11] 2. A method for inspecting the columnar honeycomb filter according to claim 1.

[0028] [ 13 The diameter of the opening of the particle concentration adjustment plate is 10,000 to 200,000 times the average particle size of the particles.

[11] or

[12] 2. A method for inspecting the columnar honeycomb filter according to claim 1.

[0029] [ 14 ] further comprising a step of calculating a particle collection efficiency of calculating the particle collection efficiency from the number of particles obtained in the particle measurement step, 11 ]~[ 13 ] The method for inspecting a pillar-shaped honeycomb filter according to any one of the following:

[0030] [ 15 ] the particles are one or more selected from soot particles, carbon particles, oil particles, NaCl particles, and resin particles; [ 11 ]~[ 14 ] The method for inspecting a pillar-shaped honeycomb filter according to any one of the following: [Effects of the Invention]

[0031] According to the present invention, it is possible to provide a columnar honeycomb filter inspection device that has high accuracy in inspecting the filtering performance and that can be made compact. Also, according to the present invention, it is possible to provide a columnar honeycomb filter inspection method that has high accuracy in inspecting the filtering performance and that can be performed in a compact environment. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a schematic view of an inspection device for a columnar honeycomb filter according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a columnar honeycomb filter used in an inspection device for a columnar honeycomb filter according to an embodiment of the present invention. [Figure 3] FIG. 3 is an end view of the pillar-shaped honeycomb filter of FIG. 2. [Figure 4] FIG. 2 is an enlarged view of the particle introduction section and its surroundings in FIG. [Figure 5] 1 is a plan view of a gas stirring plate used in an inspection device for a columnar honeycomb filter according to an embodiment of the present invention. FIG. [Figure 6] FIG. 6 is a cross-sectional view of the gas agitating plate taken along line aa' in FIG. 5. [Figure 7] 1 is a plan view of a particle concentration adjustment plate used in an inspection device for a columnar honeycomb filter according to an embodiment of the present invention. [Figure 8] 8 is a cross-sectional view of the particle concentration adjusting plate taken along line bb' in FIG. 7. [Figure 9] FIG. 10 is a schematic view of another columnar honeycomb filter inspection device according to an embodiment of the present invention. [Figure 10] FIG. 2 is a cross-sectional view of an introduction pipe for explaining measurement positions of particles in the introduction pipe in an example. DETAILED DESCRIPTION OF THE INVENTION

[0033] The following is a detailed description of the embodiments of the present invention. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also within the scope of the present invention.

[0034] (1) Inspection equipment for columnar honeycomb filters FIG. 1 is a schematic diagram of an inspection device for a pillar-shaped honeycomb filter according to an embodiment of the present invention. As shown in FIG. 1, the inspection device 100 for a columnar honeycomb filter includes a storage section 10 capable of storing a columnar honeycomb filter, an inlet pipe 20 and an outlet pipe 30 through which gas can flow and which are connected to the storage section 10, a particle generating section 40 which generates particles, a particle introducing section 50 which introduces the particles generated in the particle generating section 40 into the inlet pipe 20, a gas agitating section 60 which is installed in the inlet pipe 20 upstream of the particle introducing section 50 in the gas flow direction X, a particle concentration adjusting section 70 which is installed in the inlet pipe 20 downstream of the particle introducing section 50 in the gas flow direction X, and particle measuring devices 80a, 80b which are installed in the inlet pipe 20 and the outlet pipe 30 downstream of the particle concentration adjusting section 70 in the gas flow direction X and which measure the number of particles. The gas agitator 60 installed upstream of the particle introduction section 50 facilitates particle diffusion in the gas. However, to ensure this effect, the length of the introduction pipe 20 must be set according to its diameter. Therefore, for example, if the diameter of the introduction pipe 20 is large, the introduction pipe 20 must be lengthened. However, by installing the particle concentration adjuster 70 downstream of the particle introduction section 50, the particle concentration distribution in the plane perpendicular to the gas flow direction X can be adjusted without lengthening the introduction pipe 20. Therefore, with the above configuration, even if the length of the introduction pipe 20 is shortened, the deviation in the particle concentration distribution in the plane perpendicular to the gas flow direction X can be sufficiently suppressed, thereby enabling the miniaturization of the inspection device 100. Furthermore, since the particle counters 80a and 80b use particles with this suppressed deviation in the concentration distribution to measure the number of particles, the accuracy of the collection performance inspection can be improved. Although FIG. 1 shows an example in which components such as the inlet pipe 20 and the outlet pipe 30 are arranged horizontally, it should be noted that these components may also be arranged vertically.

[0035] The columnar honeycomb filter to be inspected and each component of the inspection device 100 for the columnar honeycomb filter will be described in detail below.

[0036] <Columnar honeycomb filter 1> The pillar-shaped honeycomb filter used in the pillar-shaped honeycomb filter inspection device 100 is a wall-flow type pillar-shaped honeycomb structure. The pillar-shaped honeycomb filter can be used as a DPF or GPF that captures PM such as soot and is installed in an exhaust gas line from a combustion device, typically an engine mounted on a vehicle.

[0037] 2 and 3 are a schematic cross-sectional view (cross-sectional view parallel to the cell extension direction) and an end view (end view of the first end face) of a pillar-shaped honeycomb filter. 2 and 3, the columnar honeycomb filter 1 includes an outer peripheral wall 2, a plurality of first cells 4a arranged inside the outer peripheral wall 2 and extending from a first end face 3a to a second end face 3b, with the first end face 3a open and the second end face 3b provided with plugging portions 6, a plurality of second cells 4b arranged inside the outer peripheral wall 2 and extending from the first end face 3a to the second end face 3b, with the first end face 3a provided with plugging portions 6 and the second end face 3b open, and porous partition walls 5 that define the first cells 4a and the second cells 4b. The first cells 4a and the second cells 4b are arranged adjacent to each other alternately with the partition walls 5 sandwiched therebetween, so that the first end face 3a and the second end face 3b each have a honeycomb shape.

[0038] When exhaust gas containing PM such as soot is supplied to the first end face 3a on the upstream side of the columnar honeycomb filter 1, the exhaust gas is introduced into the first cells 4a and travels downstream within the first cells 4a. Because the first cells 4a have plugging portions 6 on the second end face 3b on the downstream side, the exhaust gas passes through the porous partition walls 5 that separate the first cells 4a and the second cells 4b and flows into the second cells 4b. PM cannot pass through the partition walls 5 and is therefore captured and deposited within the first cells 4a. After the PM is removed, the clean exhaust gas that has flowed into the second cells 4b travels downstream within the second cells 4b and flows out from the second end face 3b on the downstream side.

[0039] The material constituting the columnar honeycomb filter 1 is not particularly limited, but examples thereof include porous ceramics. Examples of ceramics include cordierite, mullite, zirconium phosphate, aluminum titanate, silicon carbide, silicon-silicon carbide composites (e.g., Si-bonded SiC), cordierite-silicon carbide composites, zirconia, spinel, indialite, sapphirine, corundum, titania, and silicon nitride. These ceramics can be used alone or in combination of two or more.

[0040] The columnar honeycomb filter 1 may have a catalyst supporting the combustion of PM supported on the surface of or inside the partition walls 5. Examples of the catalyst include noble metals (Pt, Pd, Rh, etc.), alkali metals (Li, Na, K, Cs, etc.), alkaline earth metals (Ca, Ba, Sr, etc.), rare earths (Ce, Sm, Gd, Nd, Y, Zr, Ca, La, Pr, etc.), and transition metals (Mn, Fe, Co, Ni, Cu, Zn, Sc, Ti, V, Cr, etc.).

[0041] The end face shape of the columnar honeycomb filter 1 is not particularly limited, and can be, for example, a round shape such as a circle, an ellipse, a racetrack shape, or an oval, or a polygonal shape such as a triangle or a rectangle. The end face shape of the columnar honeycomb filter 1 is the same as the cross-sectional shape perpendicular to the extension direction of the cells (first cells 4a and second cells 4b). The illustrated columnar honeycomb filter 1 is an example in which the end face shape is circular and the outer shape is cylindrical.

[0042] The diameter of the columnar honeycomb filter 1 is not particularly limited, but is preferably 90 to 356 mm. When inspecting the collection performance of a columnar honeycomb filter 1 having such a diameter, conventional inspection devices tend to require a long introduction pipe, which makes the device large. However, the columnar honeycomb filter inspection device 100 does not require a long introduction pipe 20, so the device can be made small. Here, in this specification, the "diameter of the columnar honeycomb filter 1" refers to the diameter (outer diameter) of the columnar honeycomb filter 1 in a cross section perpendicular to the extension direction of the cells (first cells 4a and second cells 4b). When the cross section of the columnar honeycomb filter 1 is not circular, the diameter of the columnar honeycomb filter 1 is defined as the diameter of the largest inscribed circle inscribed in the cross section.

[0043] The shape of the cells (first cells 4a and second cells 4b) in a cross section perpendicular to the flow direction is not particularly limited, but is preferably a rectangle, a hexagon, an octagon, or a combination thereof. Among these, a square and a hexagon are more preferable. By using such a cell shape, the pressure loss when a fluid flows through the columnar honeycomb filter 1 can be reduced.

[0044] The cell density (the number of cells per unit cross-sectional area) is not particularly limited, and may be, for example, 6 to 2000 cells / square inch (0.9 to 311 cells / cm 2 ), preferably 50 to 1000 cells / in² (7.8 to 155 cells / cm²) 2 ), more preferably 100 to 400 cells / in² (15.5 to 62.0 cells / cm²) 2 ) can be used.

[0045] The columnar honeycomb filter 1 can also be provided as an integrally molded product. The columnar honeycomb filter 1 can also be provided as a segment bonded body formed by bonding side surfaces of a plurality of columnar honeycomb segments, each having an outer peripheral wall 2, together to form an integrated body. By providing the columnar honeycomb filter 1 as a segment bonded body, it is possible to improve thermal shock resistance.

[0046] The pillar-shaped honeycomb filter 1 can be manufactured by a method known in the art. An example of a method for manufacturing the pillar-shaped honeycomb filter 1 will be described below. First, a raw material composition containing ceramic raw materials, a dispersion medium, a pore-forming material, and a binder is kneaded to form a clay, and then the clay is extruded to form the desired columnar honeycomb molded body. Additives such as a dispersant can be blended into the raw material composition as needed. During extrusion molding, a die having the desired overall shape, cell shape, partition wall thickness, cell density, etc. can be used.

[0047] After drying the columnar honeycomb formed body, plugging portions (uncured state) are formed on both end faces of the columnar honeycomb formed body, and then the plugging portions (uncured state) are dried to obtain a columnar honeycomb formed body having plugging portions (dry state). Thereafter, the columnar honeycomb formed body is degreased and fired to produce the columnar honeycomb filter 1.

[0048] As the ceramic raw material, a raw material capable of forming the above-mentioned ceramics after firing can be used. The ceramic raw material can be provided, for example, in the form of a powder. Examples of the ceramic raw material include raw materials for obtaining ceramics such as cordierite, mullite, zircon, aluminum titanate, silicon carbide, silicon nitride, zirconia, spinel, indialite, sapphirine, corundum, and titania. More specifically, examples include, but are not limited to, silica, talc, alumina, kaolin, serpentine, pyroferrite, brucite, boehmite, mullite, magnesite, and aluminum hydroxide. The ceramic raw material can be used alone or in combination of two or more types.

[0049] In the case of filter applications such as DPF and GPF, cordierite can be suitably used as the ceramic. In this case, a cordierite-forming raw material can be used as the ceramic raw material. The cordierite-forming raw material is a raw material that becomes cordierite when fired. The cordierite-forming raw material preferably has a chemical composition of 30 to 45 mass% alumina (Al2O3) (including aluminum hydroxide converted to alumina), 11 to 17 mass% magnesia (MgO), and 42 to 57 mass% silica (SiO2).

[0050] Examples of the dispersion medium include water and a mixed solvent of water and an organic solvent such as alcohol, with water being particularly preferred.

[0051] The pore-forming material is not particularly limited as long as it forms pores after firing, and examples thereof include wheat flour, starch, foamed resin, water-absorbent resin, porous silica, carbon (e.g., graphite), ceramic balloons, polyethylene, polystyrene, polypropylene, nylon, polyester, acrylic, and phenol. The pore-forming material can be used alone or in combination of two or more. From the viewpoint of increasing the porosity of the fired body, the content of the pore-forming material is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of the ceramic raw material. From the viewpoint of ensuring the strength of the fired body, the content of the pore-forming material is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 4 parts by mass or less, per 100 parts by mass of the ceramic raw material.

[0052] Examples of binders include organic binders such as methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, it is preferable to use methyl cellulose and hydroxypropyl methyl cellulose in combination. Furthermore, from the viewpoint of increasing the strength of the honeycomb formed body, the content of the binder is preferably 4 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 6 parts by mass or more, per 100 parts by mass of the ceramic raw materials. From the viewpoint of suppressing cracks due to abnormal heat generation during the firing process, the content of the binder is preferably 9 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less, per 100 parts by mass of the ceramic raw materials. The binder may be used alone or in combination of two or more types.

[0053] Examples of dispersants that can be used include ethylene glycol, dextrin, fatty acid soap, and polyether polyol. The dispersants can be used alone or in combination of two or more. The content of the dispersant is preferably 0 to 2 parts by mass per 100 parts by mass of the ceramic raw material.

[0054] The method for plugging the end faces of the columnar honeycomb formed body is not particularly limited, and well-known methods can be used. The material for the plugging portions 6 is not particularly limited, but ceramics are preferred from the viewpoints of strength and heat resistance. The ceramic is preferably a ceramic material containing at least one selected from the group consisting of cordierite, mullite, zircon, aluminum titanate, silicon carbide, silicon nitride, zirconia, spinel, indialite, sapphirine, corundum, and titania. It is even more preferred that the plugging portions 6 have the same material composition as the main body of the honeycomb formed body, as this allows the expansion coefficients during firing to be the same, leading to improved durability.

[0055] After drying the honeycomb molded body, degreasing and firing are carried out to manufacture the columnar honeycomb filter 1. Known conditions may be adopted for the drying, degreasing and firing processes depending on the material composition of the honeycomb molded body, and no particular explanation is required, but examples of specific conditions are given below.

[0056] In the drying step, conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze drying can be used. Among these, a drying method that combines hot air drying with microwave drying or dielectric drying is preferred because it can quickly and uniformly dry the entire formed body. When forming plugging portions 6, it is preferable to form plugging portions (in an uncured state) on both end faces of the dried honeycomb formed body and then dry the plugging portions (in an uncured state).

[0057] Next, the degreasing step will be described. The combustion temperature of the binder is about 200°C, and the combustion temperature of the pore-forming material is about 300 to 1000°C. Therefore, the degreasing step can be carried out by heating the honeycomb formed body to a temperature in the range of about 200 to 1000°C. The heating time is not particularly limited, but is usually about 10 to 100 hours. The honeycomb formed body after the degreasing step is called a calcined body.

[0058] The firing step may be carried out by heating the calcined body to 1350 to 1600° C. and holding the calcined body for 3 to 10 hours, although this depends on the material composition of the honeycomb formed body.

[0059] The honeycomb formed body after firing may be used as a filter as it is, but in order to increase the PN collection efficiency, a porous film for capturing PM may be separately formed on the partition walls 5. Any known method can be used as a method for forming the porous film. In one embodiment, the porous film may contain 50 mass% or more in total of one or more types selected from silicon carbide, cordierite, alumina, silica, mullite, and aluminum titanate.

[0060] <Containment Unit 10> The housing portion 10 is a member capable of housing the columnar honeycomb filter 1 therein. The shape of the accommodating section 10 is not particularly limited and can be set appropriately depending on the shape of the pillar-shaped honeycomb filter 1. For example, when the pillar-shaped honeycomb filter 1 has a cylindrical outer shape, the accommodating section 10 can be cylindrical. In the accommodation portion 10, the columnar honeycomb filter 1 is accommodated with the first end face 3a facing the inlet pipe 20 side and the second end face 3b facing the outlet pipe 30 side. Materials that can be used for the housing unit 10 include, for example, metals and ceramics. Examples of metals include stainless steel, titanium alloys, copper alloys, aluminum alloys, brass, etc. Stainless steel is preferred as the material for the housing unit 10 because of its high durability and reliability.

[0061] <Inlet pipe 20 and outlet pipe 30> The inlet pipe 20 and the outlet pipe 30 are members through which gas can flow and which are connected to the storage unit 10. The inlet pipe 20 is located upstream of the storage unit 10 in the gas flow direction X. The outlet pipe 30 is located downstream of the storage unit 10 in the gas flow direction X. The shapes of the inlet pipe 20 and the outlet pipe 30 are not particularly limited, and may be cylindrical, with a circular cross section perpendicular to the gas flow direction X, a rectangular tube with a triangular, rectangular, pentagonal, hexagonal or other rectangular cross section, an elliptical tube with an elliptical cross section, etc. Among these, the inlet pipe 20 and the outlet pipe 30 are preferably cylindrical.

[0062] The diameter of the inlet pipe 20 is not particularly limited, but is preferably 150 to 270 mm. The inlet pipe 20 having a diameter in this range is suitable for the inspection device 100 for the columnar honeycomb filters 1 used in DPFs and GPFs of various sizes. The diameter of the discharge pipe 30 is not particularly limited, but may be the same as that of the introduction pipe 20 . Here, in this specification, the "diameter of the inlet pipe 20 and the outlet pipe 30" means the diameter (inner diameter) of the inlet pipe 20 and the outlet pipe 30 in a cross section perpendicular to the gas flow direction X. If the cross-sectional shape of the inlet pipe 20 and the outlet pipe 30 is not circular, the diameter (inner diameter) of the largest inscribed circle inscribed in the cross-sectional shape is defined as the diameter of the inlet pipe 20 and the outlet pipe 30. The diameters of the inlet pipe 20 and the outlet pipe 30 may be partially expanded and / or reduced. Such a configuration makes it easier to connect to other components or to arrange other components, for example. When partially expanding and / or reducing the diameter of the inlet pipe 20, it is preferable that the diameter of the inlet pipe 20 downstream of the gas agitator 60 in the gas flow direction X is kept constant, and the diameter of the other portions is expanded and / or reduced.

[0063] The inlet pipe 20 and the outlet pipe 30 may be made of, for example, metal or ceramic. Examples of metal include stainless steel, titanium alloy, copper alloy, aluminum alloy, brass, etc. Stainless steel is preferred as the material for the inlet pipe 20 and the outlet pipe 30 because of its high durability and reliability.

[0064] <Particle generating unit 40> The particle generating section 40 is a section that generates particles to be introduced into the columnar honeycomb filter 1. The particle generating section 40 can generate a gas containing particles. The gas in the gas containing particles is not particularly limited, and examples thereof include air, nitrogen, helium, hydrogen, and argon. Among these, air is preferred from the viewpoints of cost and safety. The particles generated by the particle generating unit 40 are not particularly limited, and examples thereof include soot particles, carbon particles, oil particles such as DEHS (bis(2-ethylhexyne) sebacate) particles, NaCl particles, and resin particles such as polystyrene latex particles. These can be used alone or in combination of two or more. When 100% inspection of the columnar honeycomb filters 1 is performed, particles remain in the columnar honeycomb filter 1 after the inspection, so it is desirable to perform a particle removal process (e.g., heat treatment). In particular, particles such as soot particles and carbon particles discolor the columnar honeycomb filter 1, so it is necessary to reliably remove the particles by heat treatment. However, heat treatment increases costs and may damage the columnar honeycomb filter 1 depending on the conditions. Therefore, when 100% inspection of the columnar honeycomb filters 1 is performed, it is preferable to select and use particles that are easy to remove (e.g., DEHS particles or resin particles). Since devices capable of generating the above-described particles are commercially available, such commercially available devices can be used as particle generating section 40 . There are no particular limitations on the particle generating unit 40, and for example, a soot particle generator capable of generating soot particles can be used. The soot particle generator is connected to, for example, a propane source, a nitrogen source, and an air source, and can generate soot particles by incompletely combusting propane.

[0065] The closer the particle size distribution of the particles generated by the particle generating unit 40 is to the particle size distribution of PM contained in actual exhaust gas, the higher the inspection accuracy. For example, PM contained in automobile exhaust gas has a number-based median diameter D50 (hereinafter, this median diameter D50 will be referred to as the "average particle size") of 50 to 100 nm in the cumulative particle size distribution determined using an electrostatic particle classifier, agglomeration particle counter, or the like. Therefore, it is ideal that the average particle size of the particles generated by the particle generating unit 40 also falls within this range. However, even particles with a particle size distribution different from that of PM contained in actual exhaust gas can be used because the collection mechanism is the same up to a particle size of 1,000 nm.

[0066] Particle collection can be divided into four main categories: (I) Diffusion (particles move differently from the flow due to Brownian motion and are collected) (II) Interception (even if they are in the flow, they are physically contacted and captured) (III) Sedimentation (large particles are pulled out of the flow by gravity and do not pass through) (IV) Inertia (large particles cannot ride the current even if the flow direction changes, and they collide and are collected) For particles up to 1000 nm in diameter, diffusion and interception are dominant, so using smaller particles makes it possible to simulate actual collection performance.

[0067] Therefore, the average particle size of the particles generated by particle generating unit 40 is preferably 100 to 1000 nm. By controlling the average particle size of the particles within this range, it is possible to stably improve the accuracy of testing the collection performance. Furthermore, when testing the filtering performance of a columnar honeycomb filter 1 with a general filtering ability, the average particle size may be within the above range. However, when testing the filtering performance of a columnar honeycomb filter 1 with a high filtering ability, if the average particle size is 300 nm or more, the test results will be almost the same, making it difficult to obtain detailed information about the filtering performance. Therefore, in such cases, the average particle size is preferably 30 nm or more but less than 300 nm, and more preferably 100 to 250 nm. By controlling the average particle size within this range, detailed information about the filtering performance can be obtained even when testing a columnar honeycomb filter 1 with a high filtering ability, thereby improving the accuracy of the filtering performance test.

[0068] <Particle introduction section 50> The particle introduction section 50 is a section that introduces particles generated in the particle generation section 40 into the introduction pipe 20. The particle introduction section 50 and the particle generation section 40 can be connected using a tubular member such as a tube. The particle introduction section 50 is not particularly limited, but from the viewpoint of uniformly introducing particles into the introduction tube 20, it is preferable to use a sprayer.

[0069] As shown in FIG. 4, the particle introduction direction in particle introduction section 50 preferably has an angle θ greater than 90°, more preferably an angle θ between 100 and 180°, even more preferably an angle θ between 150 and 180°, and particularly preferably an angle θ of 180°, relative to the gas flow direction X. FIG. 4 is an enlarged view of the periphery of particle introduction section 50 shown in FIG. 1. By controlling the particle introduction direction in this manner, particles are more easily dispersed in the gas, thereby effectively suppressing bias in the particle concentration distribution in a plane perpendicular to the gas flow direction X. Then, particles with this suppressed bias in the concentration distribution are used to count the particles using particle counters 80a and 80b, thereby further improving the accuracy of the collection performance inspection. The particle introduction section 50 preferably has a particle outlet facing the gas flow direction X, and more preferably has a particle outlet facing the gas flow direction X. By providing the outlet in such a position, the particles can be introduced at an angle θ of more than 90° with respect to the gas flow direction X. Various conditions such as the amount and speed of particles introduced into particle introduction part 50 may be appropriately set depending on the type of particle introduction part 50, the size of introduction pipe 20, etc., and are not particularly limited.

[0070] <Gas agitation unit 60> The gas agitator 60 is a member having a function of agitating the gas, and is installed in the introduction pipe 20 on the upstream side of the particle introduction part 50 in the gas flow direction X. The gas agitator 60 is not particularly limited, but is preferably a gas agitator plate. Here, a plan view of a typical gas agitating plate (a plan view seen from the upstream side in the gas flow direction X) is shown in Fig. 5. Also, a cross-sectional view taken along line aa' in Fig. 5 is shown in Fig. 6. 5 and 6, the gas agitating plate 61 has a pair of flat surfaces 62a and 62b perpendicular to the gas flow direction X, and a plurality of openings 63 are formed through the pair of flat surfaces 62a and 62b. The openings 63 of the gas agitating plate 61 are provided in an area extending from the outer periphery of the pair of flat surfaces 62a and 62b to 1 / 2, preferably 2 / 5, and more preferably 3 / 10 of the diameter of the pair of flat surfaces 62a and 62b. By using the gas agitation plate 61 having the above-described structure as the gas agitation unit 60, negative pressure is created on the downstream side of the gas agitation plate 61 (the side of the flat surface 62b), causing a backflow of gas and forming a recirculation flow. In particular, by providing multiple openings 63 in the outer peripheral region of the gas agitation plate 61, a recirculation flow is easily formed on the downstream side of the gas agitation plate 61. By introducing particles into this region through the particle introduction section 50, the particles are entrained in the recirculation flow and diffuse into the gas, thereby suppressing unevenness in the particle concentration distribution in a plane perpendicular to the gas flow direction X. As a result, it is possible to uniformly supply particles to the columnar honeycomb filter 1 to be inspected. Furthermore, the gas agitation plate 61 has a simpler structure than an agitation device having a rotating blade mechanism and does not require external power, thereby reducing various costs.

[0071] The opening ratio of the gas agitating plate 61 is preferably 5 to 50%, and more preferably 10 to 40%. By controlling the opening ratio to such an extent, a recirculation flow is easily formed on the downstream side of the gas agitating plate 61, which increases the effect of diffusing particles into the gas. Here, the opening ratio of the gas agitating plate 61 means, for example, the ratio of the area of ​​the openings 63 to the total area of ​​the plane 62a and the openings 63 in the plan view of FIG.

[0072] The shape of the opening 63 of the gas agitating plate 61 is not particularly limited, and for example, the cross-sectional shape perpendicular to the gas flow direction X can be a polygon such as a circle, an ellipse, a triangle, a rectangle, etc. Among these, the cross-sectional shape of the opening 63 is preferably a circle.

[0073] The diameter of the opening 63 of the gas agitation plate 61 is not particularly limited and may be set appropriately depending on the size of the gas agitation plate 61. Specifically, the diameter of the opening 63 in the gas agitation plate 61 may be large enough to cause a backflow of gas and form a recirculation flow. Here, the diameter of the opening 63 of the gas agitation plate 61 means the diameter of the opening 63 in a cross section perpendicular to the gas flow direction X. If the cross-sectional shape of the opening 63 of the gas agitation plate 61 is not circular, the diameter of the opening 63 of the gas agitation plate 61 is the diameter of the largest inscribed circle inscribed in the cross-sectional shape.

[0074] The recirculation flow on the downstream side of the gas stirring plate 61 is more easily formed as the flow velocity (flow rate) of the gas flowing through the inlet pipe 20 increases. Therefore, the flow rate of the gas is preferably 500 to 20,000 L / min.

[0075] The size of the gas agitation plate 61 is not particularly limited and may be adjusted appropriately depending on the size of the introduction pipe 20 in which the gas agitation plate 61 is installed. For example, the outer diameter of the gas agitation plate 61 may be set to correspond to the inner diameter of the introduction pipe 20. The material for the gas agitating plate 61 may be, for example, metal or ceramic. Examples of metal include stainless steel, titanium alloy, copper alloy, aluminum alloy, brass, etc. The material for the gas agitating plate 61 is preferably stainless steel because of its high durability and reliability.

[0076] The distance between particle introduction section 50 and gas agitation section 60 in gas flow direction X is preferably no more than 3 times, and more preferably no more than 2.5 times, the inner diameter of introduction pipe 20 at the position where gas agitation section 60 is located. By controlling the distance between particle introduction section 50 and gas agitation section 60 within this range, particles can be stably introduced into the region where a recirculation flow is formed, thereby increasing the effectiveness of diffusing the particles into the gas.

[0077] The gas agitated by the gas agitation unit 60 (gas that serves as a particle carrier) is not particularly limited, and examples thereof include air, nitrogen, helium, hydrogen, argon, etc. Among these, air is preferred from the viewpoints of cost and safety.

[0078] <Particle concentration adjustment section 70> The particle concentration adjusting unit 70 is a member that adjusts the particle concentration distribution in a plane perpendicular to the gas flow direction X. The particle concentration adjusting unit 70 is installed in the introduction pipe 20 downstream of the particle introduction unit 50 in the gas flow direction X. The particle concentration adjusting section 70 is not particularly limited, but is preferably a particle concentration adjusting plate. A plan view of a typical particle concentration adjusting plate (as viewed from the upstream side in the gas flow direction X) is shown in Fig. 7. A cross-sectional view taken along line bb' in Fig. 7 is shown in Fig. 8. As shown in FIGS. 7 and 8, the particle concentration adjusting plate 71 has a pair of flat surfaces 72a and 72b perpendicular to the gas flow direction X, and a plurality of openings 73 penetrating the pair of flat surfaces 72a and 72b are formed. By using the particle concentration adjusting plate 71 as the particle concentration adjusting section 70, even if the length of the inlet pipe 20 downstream of the gas agitator 60 in the gas flow direction X is shortened, the particle concentration distribution in the plane perpendicular to the gas flow direction X can be adjusted, and bias in the particle concentration distribution in the plane perpendicular to the gas flow direction X can be suppressed. As a result, it becomes possible to supply particles uniformly to the columnar honeycomb filter 1 to be inspected. Furthermore, the particle concentration adjusting plate 71 has a simpler structure than concentration adjusting devices having various drive mechanisms and does not require external power, thereby reducing various costs.

[0079] In the particle concentration adjusting plate 71, the plurality of openings 73 are preferably provided in an area on the inner periphery of the particle concentration adjusting plate 71. By providing the plurality of openings 73 in such an area, it becomes easier to adjust the particle concentration distribution in a plane perpendicular to the gas flow direction X. Here, the inner peripheral side of the particle concentration adjusting plate 71 refers to the region from the center of the pair of flat surfaces 72a, 72b to 4 / 5 of the diameter of the pair of flat surfaces 72a, 72b (for example, the radius if the surface is disk-shaped).

[0080] The particle concentration adjusting plate 71 preferably has an opening ratio of 30% or more, more preferably 40 to 80%, and even more preferably 50 to 70%. By controlling the opening ratio to such an extent, it becomes easier to stably adjust the particle concentration distribution in a plane perpendicular to the gas flow direction X. Here, the opening ratio of the particle concentration adjusting plate 71 means, for example, the ratio of the area of ​​the openings 73 to the total area of ​​the plane 72a and the openings 73 in the plan view of FIG.

[0081] The shape of the opening 73 of the particle concentration adjusting plate 71 is not particularly limited, and for example, the cross-sectional shape perpendicular to the gas flow direction X can be a polygon such as a circle, an ellipse, a triangle, a rectangle, etc. Among these, the cross-sectional shape of the opening 73 is preferably a circle.

[0082] The diameter of openings 73 of particle concentration adjusting plate 71 may be set appropriately depending on the size of particle concentration adjusting plate 71, but is preferably 10,000 to 200,000 times the average particle size of the particles generated in particle generating section 40. By controlling the diameter of openings 73 to fall within this range, it becomes easier to adjust the particle concentration distribution in a plane perpendicular to gas flow direction X. Here, the diameter of the opening 73 of the particle concentration adjusting plate 71 means the diameter of the opening 73 in a cross section perpendicular to the gas flow direction X. If the cross-sectional shape of the opening 73 of the particle concentration adjusting plate 71 is not circular, the diameter of the largest inscribed circle inscribed in the cross-sectional shape is defined as the diameter of the opening 73 of the particle concentration adjusting plate 71. The shape and diameter of the opening 73 of the particle concentration adjusting plate 71 may be different from or the same as the shape and diameter of the opening 63 of the gas agitating plate 61. By making the shape and diameter of the opening 73 of the particle concentration adjusting plate 71 and the opening 63 of the gas agitating plate 61 the same, the particle concentration adjusting plate 71 and the gas agitating plate 61 can be manufactured easily.

[0083] The size of the particle concentration adjusting plate 71 is not particularly limited and may be adjusted appropriately depending on the size of the introduction pipe 20 in which the particle concentration adjusting plate 71 is installed. For example, the outer diameter of the particle concentration adjusting plate 71 may be set to correspond to the inner diameter of the introduction pipe 20. Examples of materials that can be used for particle concentration adjustment plate 71 include metals and ceramics. Examples of metals include stainless steel, titanium alloys, copper alloys, aluminum alloys, brass, etc. Stainless steel is preferred as the material for particle concentration adjustment plate 71 because of its high durability and reliability.

[0084] By using the particle concentration adjusting section 70 (particle concentration adjusting plate 71) as described above, the length of the introduction pipe 20 downstream of the gas agitating section 60 in the gas flow direction X can be shortened. Specifically, the distance between the downstream end of the introduction pipe 20 and the particle introduction section 50 in the gas flow direction X is preferably 5 to 10 times the diameter of the introduction pipe 20. More specifically, the distance between the downstream end of the introduction pipe 20 and the particle introduction section 50 in the gas flow direction X is preferably 1400 to 2600 mm. With such a distance, it is possible to suppress bias in the particle concentration distribution in a plane perpendicular to the gas flow direction X, and to stably supply particles uniformly to the columnar honeycomb filter 1 to be inspected.

[0085] <Particle measuring instruments 80a, 80b> The particle measuring instruments 80a and 80b are devices that measure the number of particles in the gas flowing through the inlet pipe 20 and the outlet pipe 30. The particle measuring instrument 80a is disposed in the inlet pipe 20 downstream of the particle introducing section 50 in the gas flow direction X. The particle measuring instrument 80b is disposed in the outlet pipe 30. The particle measuring instruments 80a and 80b are not particularly limited as long as they can measure the number of particles contained in the gas. However, when inspecting the collection performance of the columnar honeycomb filter 1 with high collection capacity, it is preferable to use particles with a small average particle size as described above. In order to measure such particles with a small average particle size, it is preferable to select the particle measuring instruments 80a and 80b that can measure the number of particles with a particle size of 100 nm or more.

[0086] For example, an optical particle counter, a laser photometer, or a dust collector can be used as the particle measuring instruments 80a and 80b. Among these, it is preferable to use an optical particle counter. By using an optical particle counter, the number of particles can be measured easily and accurately. Optical particle counters are commercially available (for example, KC-24 or KC-22B manufactured by Rion Co., Ltd.), and therefore such commercially available products can be used as the particle measuring instruments 80a and 80b.

[0087] The distance between particle introduction part 50 and particle measuring instrument 80a installed in introduction pipe 20 in gas flow direction X is preferably at least twice the inner diameter of introduction pipe 20 at the position where particle measuring instrument 80a is placed. By placing particle measuring instrument 80a in such a range, the number of particles contained in the gas can be accurately measured.

[0088] The inspection device 100 for the columnar honeycomb filter 1 according to the embodiment of the present invention may further include a diluter 90 for adjusting the particle concentration, if necessary, in the middle of the connecting pipe connecting the inlet pipe 20 and the particle measuring instrument 80a, and in the middle of the connecting pipe connecting the outlet pipe 30 and the particle measuring instrument 80b, as shown in Fig. 9. Diluters 90 having such a function are commercially available (for example, Model 3332 manufactured by TSI), and therefore, such commercially available products can be used. When optical particle counters are selected as the particle measuring instruments 80a and 80b, it is desirable to lower the particle concentration in the gas because optical particle counters are easily contaminated by particles. Therefore, by providing the diluter 90 at the above position, the particle concentration can be adjusted, thereby suppressing contamination of the optical particle counters.

[0089] The diluter 90 preferably dilutes the concentration of particles in the gas by a factor of 2 to 1000. Such a dilution factor can stably suppress contamination of the optical particle counter.

[0090] The inspection device 100 for the columnar honeycomb filter 1 according to the embodiment of the present invention may further include, as necessary, a calculation unit 95 that calculates the particle collection efficiency based on the number of particles measured by particle measuring instruments 80a, 80b installed in the inlet pipe 20 and the outlet pipe 30, as shown in Fig. 9. An example of the calculation unit 95 having such a function is a computer. By providing such a calculation unit 95, the collection efficiency can be calculated in real time, and therefore the test can be carried out quickly.

[0091] (2) Inspection method for columnar honeycomb filter 1 The inspection method for a columnar honeycomb filter 1 according to an embodiment of the present invention includes a particle generating step (S1), a particle introducing step (S2), a particle concentration adjusting step (S3), a particle supplying step (S4), and a particle measuring step (S5). By performing these steps, the collection performance of the columnar honeycomb filter 1 can be inspected in a compact environment, and the inspection accuracy can be improved. This inspection method can be performed using the inspection device 100 for the columnar honeycomb filter 1 described above.

[0092] The particle generating step (S1) is a step of generating particles. This step can be performed by starting the particle generating unit 40 in the inspection device 100 for the columnar honeycomb filter 1.

[0093] The particle introduction step (S2) is a step of introducing the particles generated in the particle generation step (S1) into the gas stirred by the gas stirring section 60. This step can be performed by using the particle introduction section 50 in the inspection device 100 for the columnar honeycomb filter 1 to introduce the particles generated in the particle generation section 40 into the introduction pipe 20. By introducing the particles into the gas in this way, the particles are more easily diffused in the gas, and therefore bias in the particle concentration distribution can be suppressed. The particle introduction direction in the particle introduction step (S2) preferably has an angle θ of more than 90° with respect to the gas flow direction X. By controlling the particle introduction direction in this way, the particles are more easily diffused in the gas, which increases the effect of suppressing bias in the particle concentration distribution in a plane perpendicular to the gas flow direction X.

[0094] The particle concentration adjusting step (S3) is a step of adjusting the particle concentration in the gas. This step can be performed in the inspection device 100 for the columnar honeycomb filter 1 by passing the gas into which particles have been introduced through a particle concentration adjusting plate 71 having a pair of flat surfaces 72a, 72b perpendicular to the gas flow direction and having a plurality of openings 73 penetrating the pair of flat surfaces 72a, 72b. By adjusting the particle concentration in this manner, even if the length of the inlet pipe 20 is shortened, the particle concentration distribution in the plane perpendicular to the gas flow direction X can be adjusted, and bias in the particle concentration distribution in the plane perpendicular to the gas flow direction X can be suppressed.

[0095] The particle supply step (S4) is a step of supplying gas with an adjusted particle concentration to the columnar honeycomb filter 1. Since the particles in the gas supplied to the columnar honeycomb filter 1 have a reduced bias in concentration distribution, it is possible to make the amount of particles supplied to the columnar honeycomb filter 1 uniform. As a result, even if the orientation or installation method of the columnar honeycomb filter 1 is different, there is less variation in the measurement values, improving the accuracy of the collection performance inspection.

[0096] The particle measuring step (S5) is a step of measuring the number of particles in the gas on the upstream side and downstream side of the columnar honeycomb filter 1 in the gas flow direction X. This step is performed using particle measuring devices 80a and 80b in the inspection device 100 for the columnar honeycomb filter 1.

[0097] The inspection method for the columnar honeycomb filter 1 according to the embodiment of the present invention may further include diluting the particle concentration in the gas in the particle measurement step (S5), if necessary. The dilution of the particle concentration is performed using a diluter 90 in the inspection device 100 for the columnar honeycomb filter 1. As described above, the particle concentration is preferably diluted by a factor of 2 to 1000. This step makes it possible to adjust the particle concentration, thereby suppressing contamination of the optical particle counter.

[0098] The inspection method for the columnar honeycomb filter 1 according to the embodiment of the present invention may further include a particle collection efficiency calculation step (S6) for calculating the particle collection efficiency from the number of particles obtained in the particle measurement step (S5), as necessary. The particle collection efficiency can be calculated by the following formula: Collection efficiency [%] = (number of particles in the gas upstream of the columnar honeycomb filter 1 - number of particles in the gas downstream of the columnar honeycomb filter 1) / number of particles in the gas upstream of the columnar honeycomb filter 1 × 100 The collection efficiency calculation step (S6) can be performed after the particle measurement step (S5), and is performed using the calculation unit 95 in the inspection device 100 for the columnar honeycomb filter 1. This step allows the collection efficiency to be calculated in real time, allowing the inspection to be carried out quickly. [Example]

[0099] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0100] Example 1 An inspection device having the structure shown in Figure 1 was fabricated as an inspection device for a columnar honeycomb filter having a diameter of approximately 330 mm. In this inspection device, a gas stirring plate and a particle concentration adjusting plate were used as the gas stirring unit and the particle concentration adjusting unit. The detailed conditions for this inspection device were as follows: Diameter of the inlet pipe (where the gas agitator and particle concentration adjustment plate are located): Approximately 261 mm Distance between the particle introduction part installed in the introduction pipe and the particle measuring device (optical particle counter): Approximately 2000 mm The area where the openings of the gas agitator plate are formed: the area from the outer periphery of the flat surface of the gas agitator plate to 2 / 5 of the diameter of the flat surface Shape of the opening of the gas agitator plate (shape of the cross section perpendicular to the gas flow direction X): circular, approximately 24 mm in diameter Opening rate of gas agitator plate: approx. 19% The area where the openings of the particle concentration adjustment plate are formed: the area from the center of the plane of the particle concentration adjustment plate to 4 / 5 of the diameter of the plane Shape of the opening of the particle concentration adjustment plate (shape of the cross section perpendicular to the gas flow direction X): circular, approximately 24 mm in diameter Particle concentration adjustment plate aperture ratio: approx. 35%

[0101] (Comparative Example 1) An inspection device was fabricated having the same structure as in Example 1, except that the particle concentration adjusting plate was not provided and the gas stirring plate was changed to one with the following conditions. The area where the openings of the gas agitator plate are formed: the area from the outer periphery of the flat surface of the gas agitator plate to 1 / 2 of the diameter of the flat surface Shape of the opening of the gas agitator plate (shape of the cross section perpendicular to the gas flow direction X): circular, approximately 24 mm in diameter Opening rate of gas agitator plate: approx. 34%

[0102] In the inspection devices prepared in Example 1 and Comparative Example 1, air containing particles with an average particle size of 200 nm was generated in the particle generating section and introduced into the introduction pipe from the particle introduction section. The introduction direction of the particles in the particle introduction section was set at an angle of 180° to the gas flow direction. The particle concentration in the air was 500 to 1000 particles / cm. 3The flow rate of the air flowing through the inlet pipe was set to 15,000 L / min (flow velocity: approximately 4.5 m / s). Using a particle counter installed in the inlet pipe, the number of particles in the air was measured at nine positions (Fig. 10) on the cross section of the inlet pipe perpendicular to the gas flow direction X.

[0103] As a result of the above measurements, it was confirmed that the particle count fluctuation was only -1.1 to 1.0% based on the average value of the measurement results at nine positions, and that the particle concentration distribution in the plane perpendicular to the gas flow direction was small with the inspection device of Example 1. In contrast, with the inspection device of Comparative Example 1, the fluctuation was -6.9 to 8.0% based on the measurement position at the center of the cross section of the introduction pipe.

[0104] As can be seen from the above results, the present invention can provide a columnar honeycomb filter inspection device that has high accuracy in inspecting the filtering performance and can be made compact. Also, the present invention can provide a columnar honeycomb filter inspection method that has high accuracy in inspecting the filtering performance and can be performed in a compact environment. [Explanation of symbols]

[0105] 1. Pillar honeycomb filter 2 Outer wall 3a 1st end surface 3b Second end surface 4a Cell 1 4b Second cell 5 Bulkhead 6 Plugging part 10 Storage section 20 Introductory tube 30 Discharge pipe 40 Particle generation unit 50 Particle introduction section 60 Gas mixing section 61 Gas stirring plate 62a,62b plane 63 Opening 70 Particle concentration adjustment section 71 Particle concentration adjustment plate 72a,72b plane 73 Opening 80a, 80b Particle counter 90 Diluter 95 Calculation Unit 100 Inspection equipment X Gas flow direction

Claims

1. a housing portion capable of housing a columnar honeycomb filter; an inlet pipe and an outlet pipe through which a gas can flow and which are connected to the storage section; a particle generating unit that generates particles; a particle introduction section that introduces the particles generated in the particle generation section into the introduction pipe; a gas agitator disposed in the gas inlet pipe upstream of the particle inlet in the gas flow direction; a particle concentration adjusting unit disposed in the inlet pipe downstream of the particle introducing unit in the gas flow direction; a particle counter that is installed in the inlet pipe and the outlet pipe downstream of the particle concentration adjusting unit in the gas flow direction and that measures the number of particles; Equipped with The gas stirring unit is a gas stirring plate having a pair of flat surfaces perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of flat surfaces, and the plurality of openings of the gas stirring plate are provided in a region from the outer periphery of the flat surfaces to 1 / 2 of the diameter of the flat surfaces, the particle concentration adjustment unit is a particle concentration adjustment plate having a pair of planes perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of planes, and the plurality of openings of the particle concentration adjustment plate are provided in an area extending from the center of the plane to 4 / 5 of the diameter of the plane.

2. The columnar honeycomb filter inspection device according to claim 1 , wherein the particle concentration adjusting plate has an opening ratio of 30% or more.

3. 3. The columnar honeycomb filter inspection device according to claim 1, wherein the diameter of the openings of the particle concentration adjusting plate is 10,000 to 200,000 times the average particle diameter of the particles.

4. The inspection device for a columnar honeycomb filter according to claim 1 or 2, wherein the distance between the downstream end of the inlet pipe and the particle inlet section in the gas flow direction is 5 to 10 times the diameter of the inlet pipe.

5. 3. The columnar honeycomb filter inspection device according to claim 1, wherein the diameter of the inlet pipe is 150 to 270 mm.

6. 3. The columnar honeycomb filter inspection device according to claim 1, wherein the distance between the downstream end of said introduction pipe and said particle introduction part in the gas flow direction is 1400 to 2600 mm.

7. 3. The inspection device for a pillar-shaped honeycomb filter according to claim 1, wherein the pillar-shaped honeycomb filter has a diameter of 90 to 356 mm.

8. 3. The columnar honeycomb filter inspection device according to claim 1, wherein the gas stirring plate has an opening ratio of 5 to 50%.

9. The inspection device for a columnar honeycomb filter as described in claim 1 or 2, further comprising a calculation unit that calculates the particle collection efficiency based on the number of particles measured by the particle measuring device installed in the inlet pipe and the outlet pipe.

10. 3. The inspection device for a pillar-shaped honeycomb filter according to claim 1 or 2, wherein the particles are one or more types selected from the group consisting of soot particles, carbon particles, oil particles, NaCl particles, and resin particles.

11. a particle generating step of generating particles; a particle introducing step of introducing the particles generated in the particle generating step into the gas stirred by the gas stirring unit; a particle concentration adjusting step of adjusting the particle concentration in the gas by a particle concentration adjusting unit; a particle supplying step of supplying the gas having the particle concentration adjusted to a columnar honeycomb filter; a particle measuring step of measuring the number of particles in the gas on the upstream side and downstream side of the columnar honeycomb filter in the gas flow direction; Including, The gas stirring unit is a gas stirring plate having a pair of flat surfaces perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of flat surfaces, and the plurality of openings of the gas stirring plate are provided in a region from the outer periphery of the flat surfaces to 1 / 2 of the diameter of the flat surfaces, a particle concentration adjustment unit that is a particle concentration adjustment plate having a pair of flat surfaces perpendicular to the gas flow direction and having a plurality of openings penetrating the pair of flat surfaces, and the plurality of openings of the particle concentration adjustment plate are provided in an area extending from the center of the flat surfaces to 4 / 5 of the diameter of the flat surfaces.

12. The method for inspecting a pillar-shaped honeycomb filter according to claim 11, wherein the particle concentration adjustment plate has an opening ratio of 30% or more.

13. The method for inspecting a pillar-shaped honeycomb filter according to claim 11 or 12, wherein the diameter of the openings of the particle concentration adjusting plate is 10,000 to 200,000 times the average particle size of the particles.

14. The method for inspecting a pillar-shaped honeycomb filter according to claim 11 or 12, further comprising a step of calculating a particle collection efficiency, which calculates a particle collection efficiency from the number of particles obtained in the particle measurement step.

15. The method for inspecting a pillar-shaped honeycomb filter according to claim 11 or 12, wherein the particles are one or more types selected from the group consisting of soot particles, carbon particles, oil particles, NaCl particles, and resin particles.

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