JP5939750B2 - Honeycomb filter defect inspection method and honeycomb filter manufacturing method - Google Patents

Description

  The present invention relates to a honeycomb filter defect inspection method, a honeycomb filter defect inspection apparatus, and a honeycomb filter manufacturing method.

  DESCRIPTION OF RELATED ART Conventionally, the defect inspection method of the honey-comb filter used as a diesel particulate filter (DPF: Diesel particulate filter) is known. For example, Patent Document 1 discloses that a gas flow containing particles is provided on the inlet end face of a honeycomb filter, and the gas flow emitted from the outlet end face of the honeycomb filter is irradiated with light to illuminate the particles.

  2A of Patent Document 1, particles are generated by the nozzle 412 in the lower chamber 436, and the gas from the upper chamber 434 is supplied into the lower chamber 436, whereby the particle-containing gas is supplied to the honeycomb filter 300. I was supplying.

Special table 2009-503508 gazette

  However, in the conventional method, the detection accuracy of defects is not sufficient.

  The present invention has been made in view of the above problems, and provides a method for inspecting a honeycomb filter for a defect, a honeycomb filter defect inspection apparatus, and a method for manufacturing a honeycomb filter, which can further improve defect detection accuracy. The purpose is to do.

One aspect of the inspection method for defects of the honeycomb filter according to the present invention is as follows.
Producing particles,
Transferring the gas containing the particles to a mixer via a pipe;
Mixing the gas containing the particles and another gas in the mixer to obtain a mixed gas;
Supplying the mixed gas in the mixer to one end face of the honeycomb filter;
Detecting a concentration distribution of particles in the gas discharged from the other end face of the honeycomb filter.

One aspect of the inspection device for defects of the honeycomb filter according to the present invention,
A particle generator for generating particles;
Piping for transferring the gas containing the particles;
A mixer connected to the pipe for mixing the gas containing the particles and another gas to provide a mixed gas;
A supply path for supplying the mixed gas in the mixer to one end face of the honeycomb filter;
A detection unit that detects a concentration distribution of particles in the gas discharged from the other end surface of the honeycomb filter.

  According to the present invention, the gas containing the particles is supplied to the mixer via the pipe, and then mixed with other gas in the mixer, so that the mixing is performed as compared with the case where the particles are generated in the mixer. Sufficiently easy to perform, the concentration of particles in the gas supplied to the honeycomb filter can be made more uniform.

  Here, it is preferable that the particles are generated by mixing water and dry ice, and the particles are generated by a two-fluid nozzle (a nozzle that mixes two fluids, gas and liquid, inside or outside the nozzle and sprays liquid fine particles). It is also preferable to generate

  Further, the concentration distribution of the particles in the exhausted gas may be detected by irradiating the exhausted gas with light and detecting the scattered light from the particles in the exhausted gas with a camera. preferable. Furthermore, it is also preferable that a scale is disposed in the field of view of the camera. In this case, where the honeycomb filter is defective can be easily grasped based on the scale in the image of the camera.

  In addition, the partition wall of the honeycomb filter is preferably porous.

  One aspect of the method for manufacturing a honeycomb filter according to the present invention includes a step of inspecting a honeycomb filter for defects by the defect inspection method of the present invention and selecting a honeycomb filter having no defect.

  According to the present invention, since the concentration of particles in the gas that reaches the honeycomb filter can be made more uniform, the detection accuracy of defects can be increased.

FIG. 1A is a perspective view of a honeycomb filter 100 to be inspected, and FIG. 1B is a view taken along the arrow Ib-Ib in FIG. FIG. 2 is a schematic cross-sectional view of a defect inspection apparatus 400 for the honeycomb filter 100. FIG. 3 is a top view around the honeycomb filter 100 of the device 400 of FIG.

  An embodiment of the invention will be described with reference to the drawings. First, the honeycomb filter 100 to be inspected in the present embodiment will be described. The honeycomb filter 100 can be used as, for example, a diesel particulate filter.

  As shown in FIGS. 1A and 1B, the target honeycomb filter 100 in the present embodiment includes partition walls 112 that form a plurality of flow paths 110 that extend in parallel to each other, and a plurality of flow paths 110. A cylinder having a sealing portion 114 that closes one end of the inside (the left end in FIG. 1B) and the other end of the remaining portion of the plurality of flow paths 110 (the right end in FIG. 1B). Is the body.

  The length in the direction in which the flow path 110 of the honeycomb filter 100 extends is not particularly limited, but may be, for example, 40 to 350 mm. Moreover, the outer diameter of the honeycomb filter 100 is not particularly limited, but may be, for example, 100 to 320 mm. The size of the cross section of the flow path 110 can be set to 0.8 to 2.5 mm on a side in the case of a square, for example. The thickness of the partition 112 can be 0.05-0.5 mm.

  The material of the partition 112 of the honeycomb filter 100 is porous ceramics (fired body). The ceramic is not particularly limited, and examples thereof include alumina, silica, mullite, cordierite, glass, oxides such as aluminum titanate, silicon carbide, silicon nitride, and metal. The aluminum titanate can further contain magnesium and / or silicon.

  As described above, the left end of a part of the plurality of channels 110 of the honeycomb filter 100 is sealed by the sealing part 114, and the right end of the remaining part of the plurality of channels 110 of the honeycomb filter 100 is sealed by the sealing part 114. Has been. As the material of the sealing portion 114, the same ceramic material as that of the honeycomb filter 100 can be used. The “part of the plurality of flow paths 110” and the “remaining part of the plurality of flow paths 110” described above are preferably arranged in a matrix when viewed from the end face side as shown in FIG. Of the plurality of flow paths arranged in the vertical direction and the horizontal direction in the horizontal direction.

  Since the honeycomb filter 100 includes the porous partition 112, the gas supplied from the left end of the flow path 110 in FIG. 1B passes through the partition 112 and reaches the adjacent flow path 110. It is discharged from the right end of the flow path 110. At this time, particles in the inflowing gas are removed by the partition 112 and function as a filter.

  Such a honeycomb filter 100 can be manufactured as follows, for example.

  First, an inorganic compound source powder, an organic binder, a solvent, and additives to be added as necessary are prepared. These are mixed by a kneader or the like to obtain a raw material mixture. The obtained raw material mixture is extruded from an extruder having an outlet opening corresponding to the shape of the partition wall, cut to a desired length, and then dried by a known method. By doing so, a green honeycomb molded body is obtained. Then, the end of the flow path of the green honeycomb molded body is sealed with a sealing material by a known method and fired, or the green honeycomb molded body is fired and the end of the flow path is sealed by a known method. That's fine.

  Here, when the green honeycomb molded body is, for example, a green honeycomb molded body of aluminum titanate, the inorganic compound source powder is an aluminum source powder such as α-alumina powder, and anatase type or rutile type titania powder. A titanium source powder is contained, and if necessary, a magnesium source powder such as magnesia powder and magnesia spinel powder and / or a silicon source powder such as silicon oxide powder and glass frit can be further contained.

  Examples of the organic binder include celluloses such as methylcellulose, carboxymethylcellulose, hydroxyalkylmethylcellulose, and sodium carboxymethylcellulose; alcohols such as polyvinyl alcohol; and lignin sulfonate. The amount of the organic binder is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and still more preferably 6 parts by weight with respect to 100 parts by weight of the inorganic compound source powder. Moreover, it is preferable that the minimum amount of an organic binder is 0.1 weight part, More preferably, it is 3 weight part.

  Examples of the additive include a pore-forming agent, a lubricant and a plasticizer, a dispersant, and a solvent.

  Examples of the pore-forming agent include carbon materials such as graphite; resins such as polyethylene, polypropylene, and polymethyl methacrylate; plant materials such as starch, nut shells, walnut shells, and corn; ice; and dry ice. The amount of pore-forming agent added is preferably 0 to 40 parts by weight, more preferably 0 to 25 parts by weight with respect to 100 parts by weight of the inorganic compound source powder.

  Lubricants and plasticizers include alcohols such as glycerin; higher fatty acids such as caprylic acid, lauric acid, palmitic acid, arachidic acid, oleic acid and stearic acid; stearic acid metal salts such as Al stearate; polyoxyalkylene alkyl Examples include ether. The addition amount of the lubricant and the plasticizer is preferably 0 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the inorganic compound source powder.

  Examples of the dispersant include inorganic acids such as nitric acid, hydrochloric acid and sulfuric acid; organic acids such as oxalic acid, citric acid, acetic acid, malic acid and lactic acid; alcohols such as methanol, ethanol and propanol; ammonium polycarboxylate Surfactant etc. are mentioned. It is preferable that the addition amount of a dispersing agent is 0-20 weight part with respect to 100 weight part of an inorganic compound source powder, More preferably, it is 2-8 weight part.

  As the solvent, for example, alcohols such as methanol, ethanol, butanol and propanol; glycols such as propylene glycol, polypropylene glycol and ethylene glycol; and water can be used. The amount of the solvent used is preferably 10 to 100 parts by weight, more preferably 20 to 80 parts by weight with respect to 100 parts by weight of the inorganic compound source powder. Moreover, the weight of the solvent with respect to the weight of the whole green honeycomb molded body is not particularly limited, but is preferably 10 to 30% by weight, and more preferably 15 to 20% by weight.

  Subsequently, an embodiment of an inspection apparatus for the honeycomb filter 100 will be described with reference to FIGS. 2 and 3.

  The inspection apparatus 400 is connected to a two-fluid nozzle (particle generator) 20 that generates a gas containing mist (particles) P, a pipe 30 that transfers a gas containing mist generated by the two-fluid nozzle 20, and a pipe 30. 2 is mixed with a gas containing mist and another gas to provide a mixed gas, and the mixed gas supplied from the mixer 40 is supplied to one end of the plurality of flow paths 110 of the honeycomb filter 100 (lower end in FIG. 2). A mist supply path 56 and a particle concentration detection unit 200. Here, the mist means fine particles of liquid dispersed in a gas, and is generated by mixing two fluids, gas and liquid, inside or outside the nozzle by the two-fluid nozzle 20.

  The two-fluid nozzle 20 receives the liquid supplied from the tank 10 via the pump 12 and receives a gas supplied from the gas source 14, for example, air via the valve V <b> 1 and the line L <b> 2, and contains mist. Is generated. The form of the two-fluid nozzle is not particularly limited. Moreover, although the diameter of mist is not specifically limited, For example, it can be set as about 0.1-10 micrometers.

  As the liquid, considering the ease of removal after the inspection, a volatile liquid is preferable, and water is particularly preferable.

  The pipe 30 supplies a gas including mist generated by the two-fluid nozzle 20 to the mixer 40. The diameter of the pipe 30 is not particularly limited, but can be 20 to 100 mm. Moreover, although the length of the piping 30 is not specifically limited, It is preferable that the distance which the mist produced | generated by the 2 fluid nozzle 20 moves is 10-1000 mm.

  The mixer 40 is for sufficiently mixing the mist supplied from the pipe 30 and the other gas supplied from the gas source 24. The shape of the mixer 40 is not particularly limited. For example, the mixer 40 has a configuration in which another gas is allowed to flow into the container at a high speed (for example, 1 to 10 m / s), or has a stirring blade in the container. Various things can be used, such as a mixer that causes turbulence of flow due to the interior provided in the container.

  Another gas (for example, air) is supplied to the mixer 40 from the gas source 24 via the valve V2. The mist concentration in the mixed gas after mixing is preferably 0.0001 to 0.01 g / L. In addition, the mist concentration in the gas containing the mist before mixing in the mixer 40 is preferably 0.0001 to 50 g / L, and more preferably 0.0001 to 5 g / L. The ratio of the mist concentration in the mixed gas after mixing to the mist concentration in the gas including the mist before mixing (mist concentration in the mixed gas after mixing / mist concentration in the gas including mist before mixing) is: Preferably it is 0.001-0.999, More preferably, it is 0.002-0.99. Moreover, the mixing ratio (ratio of supply amount) of the gas containing mist before mixing and other gas is a volume ratio (volume of gas containing mist / volume of other gas), preferably 0.001 to 0.001. It is 999, More preferably, it is 0.002-499.

  The mist supply path 56 has a pipe 54 connected to the mixer 40 and a filter connection part 53 connected to the tip of the pipe 54. The filter connecting portion 53 includes a cylindrical seal portion 51 that surrounds and seals one end portion (the lower end portion in FIG. 2) in the axial direction of the honeycomb filter 100 (the axial direction of the plurality of flow paths 110) from the outside, and a plurality of flow paths. A space forming portion 52 that forms an inverted conical space V in a portion facing the lower end 110b of the path 110 is provided. Although the flow rate of the mixed gas supplied with respect to the honey-comb filter 100 is not specifically limited, For example, it can be set as 100-500 L / min.

  The gas of the gas supply sources 14 and 24 is not particularly limited, but air is preferable from the viewpoint of economy. The gases of the gas supply sources 14, 24 may be the same as each other or different from each other.

  Moreover, it is preferable that the temperature of the gas of the gas supply sources 14 and 24 is 0-50 degreeC, and it is more preferable that it is 0-30 degreeC.

  2 includes a laser light source 210 that generates a laser sheet LS, a camera 220 that captures the laser sheet LS, a computer 230 that analyzes an image acquired by the camera 220, and a field of view acquired by the camera 220. Scales 260A and 260B are provided at the entry positions.

  In the present embodiment, as shown in FIG. 2, the laser sheet LS is irradiated in parallel to an XY plane that is perpendicular to the Z direction in which the plurality of flow paths 110 of the honeycomb filter 100 extend, and the camera 220 is a laser sheet. A portion of the laser sheet LS facing the upper end surface 110t of the honeycomb filter 110 is photographed from a direction perpendicular to the LS (Z direction).

  A field of view FV of an image captured by the camera 220 is shown in FIG. Scales 260A and 260B are disposed in the field of view FV. The scales 260A and 260B extend in the Y direction and the X direction, respectively, and have marks 261 at positions corresponding to the central axes of the plurality of flow paths 110 of the honeycomb filter 100, respectively.

  Returning to FIG. 2, the computer 230 analyzes an image captured by the camera 220 and detects a portion where particles are discharged. For example, a portion brighter than a predetermined threshold value may be extracted from the image, and this portion may be set as a place where particles are discharged. The computer acquires and outputs the coordinates of this part as necessary.

  Next, an inspection method for the honeycomb filter 100 using the above-described inspection apparatus 400 will be described.

  Here, as an example, as shown in FIG. 2, the partition wall 112 of the honeycomb filter 100 has, as a defect, a hole h that communicates the flow path 110x with the upper end sealed and the flow path 110y with the lower end sealed. It shall be. Here, as shown in FIG. 3, the channel 110x is at the position of the leftmost mark 261 on the scale 260B and at the position of the third mark 261 from the bottom on the scale 260A. On the other hand, it is assumed that the flow path 110y is at the position of the second mark 261 from the left on the scale 260B, and is at the position of the third mark 261 from the bottom on the scale 260A.

  Returning to FIG. 2, first, the filter connecting portion 53 is attached to the lower portion of the honeycomb filter 100. Then, the valve V1 is opened and the pump P12 is driven to generate gas containing mist from the two-fluid nozzle 20 (step of generating particles). The gas containing the generated mist is supplied to the mixer 40 via the pipe 30 (transfer process). Subsequently, the valve V2 is adjusted to supply the gas from the gas source 24 to the mixer 40 via the line L3. Thereby, in the mixer 40, the gas containing the mist from the piping 30 and the gas from the line L3 are mixed, and a mixed gas with high uniformity of the mist concentration is obtained (mixing step). And this mixed gas is supplied to the honey-comb filter 100 via the mist supply path 56 (supply process). Thereby, gas flows out from the upper ends 110t of the plurality of flow paths 110 of the honeycomb filter 100. At this time, in the vicinity of the upper ends 110t of the plurality of flow paths 110 of the honeycomb filter 100, it is preferable that the atmosphere gas hardly flow, for example, the flow rate is 1 m / s or less. Moreover, it is preferable that the temperature of atmospheric gas is 0-30 degreeC from the ease of experiment. The atmospheric gas is preferably air.

  And when the hole h as shown in FIG. 2 exists between the flow paths 110, the flow path which connects the upper end 110t and the lower end 110b of the some flow path 110 by the flow path 110x, the hole h, and the flow path 110y. Therefore, as shown by the arrow G, the mixed gas containing mist flows out from the upper end of the defective flow path 110y intensively at a higher flow rate and flow velocity than the other flow paths 110. Similarly, when the sealing part 114 is missing or when there is a defect such as a gap between the sealing part 114 and the flow path 110, the mixed gas containing mist flows out in a concentrated manner. Therefore, above such a flow path 110y, the concentration of mist is relatively higher than in other portions.

  When the gas flowing out from the upper end of the honeycomb filter 100 has non-uniform mist concentration, the high-density portion scatters laser light strongly when passing through the laser sheet LS, and the image captured by the camera 220 is Appears as a relatively bright area. Depending on the presence or absence of this bright portion, it is possible to detect particle density unevenness (particle concentration distribution detection step).

  Then, as shown in FIG. 3, in the field of view FV of the image, for example, bright spots are generated on the third mark 261 from the bottom of the scale 260A and on the second mark 261 from the left of the scale 260B. In some cases, data of coordinates (3, 2) can be obtained, which makes it easy to identify the defect location.

  When there is no defect such as communication between the channels 110, the mixed gas flows through the partition walls 112, which are porous bodies, and flows out from the upper end outlet, as indicated by an arrow H in FIG. At this time, the mist in the mixed gas may be collected entirely, partially collected, or not collected at all depending on the diameter of the mist, the size of the pores of the partition 112, etc. Even so, the flow velocity and flow rate of the gas flowing out from the upper ends of the respective flow paths 110 are substantially uniform with each other, and therefore, the mist concentration is not likely to be uneven on the upper end 110 of the flow path 110.

  According to the present invention, by detecting the concentration distribution of particles in the gas flowing out from the flow path 110, the presence or absence and location of the flow path can be easily detected.

  In particular, in the present embodiment, when a gas containing mist is supplied to the mixer 40 via the pipe 30 and then mixed with other gas in the mixer 40, the mist is generated in the mixer 40. In comparison, it is easy to sufficiently mix mist in the gas, and the concentration of mist in the gas supplied to the honeycomb filter 100 can be made more uniform. For this reason, problems as described below are reduced, and the presence or absence of a channel defect can be detected with high accuracy. For example, if the concentration of mist in the gas supplied to the honeycomb filter 100 is not uniform, the supply gas is included in the gas discharged through the honeycomb filter 100 even though there is no defect in the flow path. There may be a mist concentration unevenness based on the mist concentration unevenness inside. In this case, based on this unevenness, there is a possibility of misidentifying that there is a defect. In addition, even if there is a defect in the flow path, there may be a case where it is difficult to produce mist from the defect due to uneven mist concentration in the supply gas. There is a case.

  Since gas containing mist is discharged from this apparatus, it is preferable to provide exhaust means for collecting these gases and exhausting them to the outside.

  Further, when manufacturing a honeycomb filter, a honeycomb filter having no defect is obtained by performing a process of inspecting the honeycomb filter for defects by the above-described inspection method and selecting a honeycomb filter having no defect in the manufacturing process. Can be selectively obtained.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the above embodiment, a two-fluid nozzle is adopted as a method for generating mist, but the present invention is not limited to this. For example, other nozzles may be used, and water and dry ice are mixed. A mist may be produced by the use of a glycol alcohol (for example, propylene glycol). Further, for example, a mist may be generated using a four-fluid nozzle or a nebulizer. The 4-fluid nozzle is a nozzle having two liquid flow paths and two gas flow paths, and causes the fluids coming out of the two liquid flow paths and the two gas flow paths to collide at the collision focus at the tip of the nozzle edge. Thus, atomized droplets are generated. By using a four-fluid nozzle, a large number of droplets of several microns can be sprayed. In addition, although it does not specifically limit as a kind of edge nozzle (4 fluid nozzle), For example, a straight edge nozzle and a circle edge nozzle are mentioned. The type of the nebulizer is not particularly limited, and examples thereof include a jet type that generates mist with compressed air, an ultrasonic type that generates mist with ultrasonic waves, and a mesh type. In the above embodiment, mist, that is, liquid particles are employed as the particles. However, the present invention is not limited to this, and the present invention can also be implemented using solid particles such as carbon black.

  Further, the direction of the laser sheet and the direction of the camera are not limited to the above embodiment.

  Further, the scales 260A and 260B may not be arranged in the visual field FV. For example, when the number of flow paths 110 is small, the defect location can be easily identified without arranging the scales 260A and 260B, or when only the presence or absence of defects is confirmed. If it is not necessary to specify the location, the scales 260A and 260B need not be used.

  In the above-described embodiment, the scattered light generated by applying light to the particle is detected as a method for detecting the concentration distribution of the particle. However, the present invention is not limited to this. For example, reflection generated by applying ultrasonic waves to the particle. A wave or the like may be detected.

  Moreover, in the said embodiment, although atmospheric gas is air, it cannot be overemphasized that other gas may be used as atmospheric gas.

  Moreover, in the said embodiment, although the flow path 110 of the honey-comb filter 100 is arrange | positioned at the up-down direction, it can implement in any direction, such as a horizontal direction.

  Moreover, in the said embodiment, although the cross-sectional shape of the flow path 110 is substantially square, it is not limited to this, It can be made into a rectangle, a circle, an ellipse, a triangle, a hexagon, an octagon, etc. Moreover, in the flow path 110, those with different diameters and those with different cross-sectional shapes may be mixed. In addition, the arrangement of the channels is also a square arrangement in FIG. 1, but is not limited to this, and may be an equilateral triangle arrangement, a staggered arrangement, etc. in which the central axis of the channel is arranged at the apex of the equilateral triangle in the cross section. it can. Further, the outer shape of the honeycomb filter is not limited to a cylinder, and may be, for example, a triangular column, a quadrangular column, a hexagonal column, an octagonal column, or the like.

  In the above-described embodiment, the honeycomb filter is a fired body in which the partition walls are porous. However, the honeycomb filter can also be implemented in a non-porous green body before firing. In this case, there is no outflow of gas from the channel without defects.

  In the above embodiment, the presence / absence of particles is determined by a computer based on an image obtained by the camera 220, but the presence / absence and position of a bright spot may be determined manually.

  As described above, according to the present invention, it is possible to provide a method for inspecting a defect in the honeycomb filter, a defect inspection apparatus for the honeycomb filter, and a method for manufacturing the honeycomb filter, which can further improve the detection accuracy of the defect. .

DESCRIPTION OF SYMBOLS 20 ... Particle generator, 30 ... Pipe, 40 ... Mixer, 53 ... Filter connection part, 56 ... Supply channel, 100 ... Honeycomb filter, 110 ... Channel, 110t ... Upper end (one end) of a channel, 110b ... Channel Lower end (the other end), 112 ... partition wall, 114 ... sealing part, 200 ... detection part, 260A, B ... scale, 400 ... inspection device, P ... mist (particle).

Claims (7)

Producing particles,
Transferring the gas containing the particles to a mixer via a pipe;
Mixing the gas containing the particles in the mixer and another gas supplied into the mixer via a line different from the gas containing the particles to obtain a mixed gas;
Supplying the mixed gas in the mixer to one end face of the honeycomb filter;
Detecting the concentration distribution of particles in the gas discharged from the other end face of the honeycomb filter ,
Irradiating the exhausted gas with light, detecting the scattered light from the particles in the exhausted gas with a camera to detect the concentration distribution of the particles in the exhausted gas;
A scale is arranged in the field of view of the camera,
Inspection method for defects in honeycomb filter.   The method of claim 1, wherein the particles are produced by mixing water and dry ice.   The method of claim 1, wherein the particles are generated by a two-fluid nozzle. The method according to any one of claims 1 to 3 , wherein the partition walls of the honeycomb filter are porous. In the step of obtaining the mixed gas, the mixing ratio of the gas containing the particles and the other gas is 0.001 to 999 in a volume ratio represented by the volume of the gas containing the particles / the volume of the other gas. The method according to any one of claims 1 to 4 , wherein The concentration of the particles in the mixed gas is 0.0001~0.01g / L, The method according to any one of claims 1-5. A method for manufacturing a honeycomb filter, comprising a step of inspecting a honeycomb filter for defects by the method according to any one of claims 1 to 6 and selecting a honeycomb filter having no defect.

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