JP2008241531A - Method and device for inspecting porous material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely and reliably detect a defect 17 in a porous material 10 without being affected by the length of the porous material 10, and the position or the size of the defect 17. <P>SOLUTION: In the inspecting method of porous material 10, fine particle gas 31 1-10 μm in diameter, generated by a fine particle generating means 30 at the lower end part 12 of the porous material 10, is induced from a chamber 21 which constitutes a fine particle gas inducing means 20. A light 41 having high directivity is generated by a light generating means 40 in appropriately parallel to the upper end part 13 of the porous material 10. The light 41 irradiates the fine particle gas 31 exhausted from the upper end part 13 of the porous material 10 to visualize the fine particle gas 31 to detect defect 17 inside the porous material 10. When the fine particle gas 31 is a glycol based alcohol vapor, generated by heating at not more than 400°C. the glycol based alcohol vapor is induced to the lower end part 12 of the porous material 10 in the state of 0 Pa by its ascending force to detect the defect 17 inside the porous material 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inspection method and an inspection apparatus for a porous body, and is particularly suitable for an inspection method for a honeycomb structure of a diesel particulate filter (DPF).

  An inspection method for detecting the position of a defect (hole) in a honeycomb structure of a porous body, for example, a diesel particulate filter (DPF), is described in Patent Document 1 below. In the following Patent Document 1, after generating the particulate gas, the particulate gas is introduced into the DPF which is the object to be inspected, and then light having strong directivity is generated so as to pass through the vicinity of the DPF. A defect in the DPF is detected by irradiating the particulate gas emitted from the DPF to visualize the particulate.

In the inspection method described above, a method of generating fine particles by burning fragrances or a method of generating by spraying glycols and / or water is described. The generated particulate gas is introduced into the DPF at a pressure of 1 to 30 Pa.
JP 2002-357562 A

  However, the inventor introduced a fine particle gas as an inspection gas at a certain pressure from the lower end of the porous body (DPF) as shown in FIG. When there is a defect, no difference in the detection rate was found in the change in the introduction pressure, but when the defect exists on the upper end (outlet) side, the detection rate decreased as the introduction pressure increased. I found it. This is because a pressure difference (pressure distribution) occurs between the lower end and the upper end of the porous body, and the pressure on the upper end becomes smaller. The fine particles on the upper end side and the lower end side are mixed through the fine holes on the lower end side in a state where the pressure is high (the state where there is almost no pressure drop). Therefore, only the fine particles that circulate through the defect on the upper end side cannot be found, and the detection rate is lower than when a defect exists on the lower end side.

  However, as shown in FIG. 7, even when the defect exists on the upper end (outlet) side, if the introduction pressure is set to a very low pressure such as less than 1 Pa (including the 0 Pa state), the defect is on the lower end side. The same detection rate was obtained as it was. That is, it has been found that if the introduction pressure is set to a very low pressure such as less than 1 Pa (including the 0 Pa state), the defect detection rate is not affected by the position in the length direction of the porous body. This is because when the introduction pressure of the particulate gas is lowered, even if there is a defect on the upper end side, the particulate gas does not circulate from the micropores on the lower end portion side because the introduction pressure is low and the ventilation resistance is not circulated. This is because the particulate gas flows from the small defect on the upper end side. When the introduction pressure is increased in this way, the pressure difference between the lower end and the upper end becomes large, and this phenomenon becomes prominent.In a porous body with a long axial length and defects on the upper end, It has been found that the detection accuracy decreases.

  In addition, when the fine particle gas is generated, as shown in FIGS. 8 and 9, for example, when a fine particle gas is generated by burning a fragrance containing carbon, 50 seconds after the generation of the fine particles, 50 seconds. It was found that the particle size of the fine particles became larger after 2 seconds. This is because the carbons thermally decomposed and activated at a high temperature aggregate in a short time and become large particles. For this reason, the fall of large particles is promoted, the dispersion of particles in the particle gas becomes non-uniform, and the detection accuracy varies. When the axial length of the porous body to be detected is long (high), the degree of dropping of large particles increases, and in the porous body in which the axial length is long and the defect exists on the upper end side, the defect detection is performed. We have found that the accuracy decreases.

  It has also been found that the particulate gas to be introduced needs to be filled in the test object at a low pressure as described above in a predetermined volume with respect to the volume of the test object.

  The present invention has been made in view of the above points, and does not thermally decompose the particulate gas containing carbon by introducing the particulate gas at a pressure of less than 1 Pa from the lower end surface of the porous body as the object to be inspected. By generating the temperature below the temperature and introducing it from the lower end surface of the porous body, it is possible to detect defects with high accuracy without being affected by the length of the porous body that is the object to be inspected, the position of defects inside the porous body, and the defect size. The object is to provide a method for examining a body. Moreover, it is providing the inspection apparatus.

  The present invention is characterized in that the introduction pressure of the particulate gas is less than 1 Pa (including the 0 Pa state). In another invention, the particulate gas to be introduced is glycol alcohol vapor generated by heating glycol alcohol at a temperature of 400 ° C. or lower.

In the invention according to claim 1, fine particle gas having a diameter of 1 to 10 μm is introduced from the lower end of the porous body, light having high directivity is generated substantially parallel to the upper end of the porous body, and the light is A method for inspecting a porous body that detects the defects in the porous body by irradiating the particulate gas discharged from the upper end portion of the porous body to visualize the particulate gas,
The fine particle gas is introduced at less than 1 Pa from the lower end of the porous body to detect defects in the porous body.

  According to the above configuration, since the particulate gas is introduced at an extremely low pressure, a defect in the porous body can be accurately and reliably detected without being affected by the position and the size of the defect. Therefore, it is a porous body having a long axial length and a defect on the upper end side, and the defect can be detected accurately and reliably.

  The invention according to claim 2 is characterized in that the introduction of the particulate gas from the lower end portion of the porous body at less than 1 Pa is introduced by the ascending force of the particulate gas itself in a 0 Pa state.

  According to the above configuration, since the fine particle gas itself is introduced by the ascending force in the 0 Pa state, the pressure difference between the lower end portion and the upper end portion of the porous body does not occur, and the fine particle gas has fine pores in the porous body. Can be suppressed, and can be detected more accurately and reliably.

  The invention according to claim 3 is characterized in that the fine particle gas is glycol alcohol vapor generated by heating glycol alcohol at a temperature of 400 ° C. or lower.

  According to the above configuration, since the fine particle gas is a glycol-based alcohol vapor generated by heating at a temperature of 400 ° C. or lower, the fine particles are enlarged and fall due to agglomeration of activated carbon by thermal decomposition in addition to the above effects. This makes it possible to make the dispersion of the fine particle gas uniform, prevent variations in inspection accuracy, and exhibit an effect in detecting a defect in a porous body having a long axial length.

In the invention according to claim 4, a fine particle gas having a diameter of 1 to 10 μm is introduced from the lower end portion of the porous body, and light having high directivity is generated substantially parallel to the upper end portion of the porous body, and the light is A method for inspecting a porous body that detects the defects in the porous body by irradiating the particulate gas discharged from the upper end portion of the porous body to visualize the particulate gas,
A glycol alcohol vapor generated by heating the particulate gas at a temperature of 400 ° C. or lower is introduced, and the glycol alcohol vapor is introduced to detect defects in the porous body.

  According to the above configuration, since the particulate gas is a glycol-based alcohol vapor generated by heating the particulate gas at a temperature of 400 ° C. or lower, it is possible to prevent large particulates from becoming large and falling due to activated carbon aggregation caused by thermal decomposition. Thus, the dispersion of the fine particle gas can be made uniform, and variations in inspection accuracy can be prevented. Therefore, the axial length is long and the defect exists on the upper end side, and the effect of accurately and reliably detecting the defect is exhibited. To do.

  The invention according to claim 5 is characterized in that the glycol alcohol vapor reacts with water vapor.

  According to the said structure, the glycol-type alcohol vapor | steam produced | generated can be made into a reliable particle form. Therefore, the detection accuracy by visualization is improved.

  The invention according to claim 6 is characterized in that at least half of the volume of the porous body of the particulate gas is filled in the porous body.

  According to the above configuration, the required amount of the fine particle gas reliably circulates within the defect, and the directivity light can be reliably visualized, and the inspection accuracy is improved.

  In the invention which concerns on Claim 7, the length from the lower end part of the said porous body to an upper end part is 10-600 mm, It is characterized by the above-mentioned.

  According to the said structure, the detection of the defect of a porous body can be made applicable by setting the length of the said porous body to 10-600 mm. In particular, the application effect is exhibited when the length is long.

  The invention according to claim 8 is characterized in that the light is generated in a planar shape.

  According to the above configuration, defects can be detected two-dimensionally as well as one-dimensionally, and a wide range of occurrence positions of defects can be detected accurately and reliably.

  The invention according to claim 9 is characterized in that the wavelength of the light is 100 to 1,000,000 nm.

  According to the said structure, a defect can be visualized reliably.

  The invention according to claim 10 is characterized in that the porous body is a honeycomb structure for a diesel particulate filter.

  According to the said structure, it is optimal for the structure of the porous body in the method of this invention, and the detection effect of a defect is exhibited most.

In the invention according to claim 11, fine particle generating means for generating fine particle gas having a diameter of 1 to 10 μm, and fine particle gas introducing means for introducing the fine particle gas generated by the fine particle gas generating means from the lower end of the porous body. Generating light that irradiates the particulate gas emitted from the upper end of the porous body so that the particulate gas is made visible by generating light having high directivity substantially parallel to the upper end of the porous body A porous body inspection device comprising means,
The particulate gas introducing means is a means for introducing the particulate gas from the lower end of the porous body at less than 1 Pa.

  According to the above configuration, since the particulate gas is introduced at an extremely low pressure by the particulate gas introducing means, the length of the porous body and the defects in the porous body can be accurately and reliably affected by the position and the size of the defects. Can be detected.

  The invention according to claim 12 is characterized in that the introduction of the particulate gas from the lower end portion of the porous body at less than 1 Pa is introduced by the ascending force of the particulate gas itself in a 0 Pa state.

  According to the above configuration, since the fine particle gas itself is introduced by the ascending force in the 0 Pa state, the pressure difference between the lower end portion and the upper end portion of the porous body does not occur, and the fine particle gas has fine pores in the porous body. Can be suppressed, and can be detected more accurately and reliably.

  The invention according to claim 13 is characterized in that the particulate gas generating means is means for generating glycol alcohol vapor by heating glycol alcohol at a temperature of 400 ° C. or lower.

  According to the above configuration, since the particulate gas is a glycol-based alcohol vapor generated by heating at a temperature of 400 ° C. or less of the glycol-based alcohol, in addition to the above effects, large particles are formed by agglomeration of activated carbon by thermal decomposition. The fine particles can be prevented from becoming large and falling, the dispersion of the fine particle gas can be made uniform, and variations in inspection accuracy can be prevented. At the same time, it is effective for detecting defects in a porous body having a long axial length.

In the invention according to claim 14, fine particle generating means for generating fine particle gas having a diameter of 1 to 10 μm, and fine particle gas introducing means for introducing the fine particle gas generated by the fine particle gas generating means from the lower end of the porous body. Generating light that irradiates the particulate gas emitted from the upper end of the porous body so as to make the particulate gas visible by generating highly directional light substantially parallel to the upper end of the porous body A porous body inspection device comprising means,
The fine particle producing means is a means for producing glycol alcohol vapor by heating glycol alcohol at a temperature of 400 ° C. or lower.

  According to the above configuration, since the particulate gas is a glycol-based alcohol vapor generated by heating at a temperature of 400 ° C. or less of the glycol-based alcohol, the particles become large and fall due to aggregation of activated carbon by thermal decomposition. And the dispersion of the fine particle gas can be made uniform, and variations in inspection accuracy can be prevented. Therefore, the effect is exhibited in the defect detection of the porous body having a long axial length.

  The invention according to claim 15 is characterized in that the glycol alcohol vapor reacts with water vapor.

  According to the said structure, the glycol-type alcohol vapor | steam produced | generated can be made into a reliable particle form. Therefore, the detection accuracy by visualization is improved.

  The invention according to claim 16 is characterized in that the particulate gas introducing means is provided with a chamber for filling the porous body with the particulate gas volume of at least half of the volume of the porous body.

  According to the above configuration, the required amount of the fine particle gas reliably circulates within the defect, and the directivity light can be reliably visualized, and the inspection accuracy is improved.

  In the invention which concerns on Claim 17, the length from the lower end part of the said porous body to an upper end part is 10-600 mm, It is characterized by the above-mentioned.

  According to the above configuration, since the introduction pressure of the particulate gas is set to less than 1 Pa, the introduction pressure distribution difference in the longitudinal direction of the porous body hardly occurs, and therefore the length of the porous body is small. Even in the case of a length of about 600 mm, it is possible to detect a defect accurately and reliably.

  The invention according to claim 18 is characterized in that the light generating means is means for generating the light in a planar shape.

  According to the above configuration, defects can be detected two-dimensionally as well as one-dimensionally, and a wide range of occurrence positions of defects can be detected accurately and reliably.

  The invention according to claim 19 is characterized in that the wavelength of the light is 100 to 1,000,000 nm.

  According to the said structure, a defect can be visualized reliably.

  The invention according to claim 20 is characterized in that the porous body is a honeycomb structure for a diesel particulate filter.

  According to the said structure, it is optimal for the structure of a porous body in this invention apparatus, and the detection effect of a defect is exhibited most.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an inspection apparatus for carrying out an inspection method according to the present invention. 2 and 3 are enlarged cross-sectional views of a porous body portion used for explaining the inspection method of the present invention.

  The porous body 10 that is a detection target is placed on a chamber 21 that constitutes a particulate gas introducing means 20. In this embodiment, the porous body 10 is a honeycomb structure DPF (diesel particulate filter) used in an exhaust gas purification device for a diesel engine. In the porous body 10, the cell holes 11 are arranged in the vertical direction, and one of both end portions is hermetically connected to the chamber 21 to the outside to form a lower end portion 12, and the other is an upper end portion 13. The cell hole 11 is formed by a thin partition 14. The cell hole 11 is alternately closed with plugs 15 at both ends 12 and 13. Innumerable fine holes 16 are formed in the partition wall 14 to form the porous body 10. The diameter of the fine hole 16 is about 10 to 20 μm (micron). In the embodiment, the DPF has a diameter of 160 mm and a shaft length L (the length between the lower end portion 12 and the upper end portion 13) of 100 mm, but the applicable length L is preferably 10 to 600 mm, which is desirable. Is 50 to 450 mm, more preferably 100 to 350 mm.

  The chamber 21 constituting the particulate gas introducing means 20 is integrally connected to the particulate gas generating means 30 that generates the particulate gas 31. The fine particle gas generating means 30 has a structure in which the generated fine particle gas 31 does not flow outside, and generates the fine particle gas 31 therein. In this embodiment, the particulate gas 31 is a mixture of glycol alcohol (propylene glycol) and distilled water, and is heated by a heater (not shown) built in a temperature of 400 ° C. or lower to generate glycol alcohol vapor. If glycol-based alcohol vapor is generated by heating glycol-based alcohol at a temperature of 400 ° C. or lower, as shown in FIGS. ) Is hardly seen.

  Also, by heating the glycol alcohol and distilled water together, the heated glycol alcohol gas acts with water vapor (the glycol alcohol gas dissolves in the water vapor) to generate glycol alcohol vapor. The glycol-based alcohol and distilled water may be separately heated in the fine particle gas generating means 30 to cause the glycol-based alcohol gas and water vapor to act. Further, by causing the glycol alcohol gas and water vapor to act, the glycol alcohol vapor can be surely made into particles. If the glycol-based alcohol vapor is made into reliable particles, distribution and visualization described later are improved. The heating temperature of the glycol alcohol is set to 400 ° C. or lower to suppress the activation of carbon by thermal decomposition, but preferably 300 ° C. or lower, and the carbon is activated and aggregated by thermal decomposition. It can be surely prevented from becoming large.

  In the present invention, the particle diameter of the particulate gas 31 generated by the particulate gas generating means 30 is preferably 1 to 10 μm according to the experiment shown in FIG. When the particle diameter exceeds 10 μm, the detection rate (accuracy) decreases.

  The chamber 21 constituting the fine particle gas introduction means 20 maintains a sufficiently large volume as compared with the volume of the porous body 10, and requires at least half of the volume of the porous body 10. The glycol alcohol vapor generated by the particulate gas generation means 30 is supplied into the chamber 21 and the chamber 21 is filled with the glycol alcohol vapor. Even in the filled state, the pressure of the glycol alcohol vapor is maintained below 1 Pa.

  Even if the pressure in the chamber 21 is 0 Pa, the glycol-based alcohol vapor in the chamber 21 rises in the cell hole 11 from the lower end portion 12 of the porous body 10 that is a detection body by its own lifting force due to its buoyancy. . When the fine particle gas 31 as the inspection gas is introduced from the lower end portion 12 of the porous body 10 by its ascending force, a pressure difference between the lower end portion 12 and the upper end portion 13 of the porous body 10 is not required, but the present invention. Then, as described with reference to FIG. 7, the introduction pressure of the particulate gas 31 from the lower end portion 12 of the porous body 10 may be set to less than 1 Pa. When the introduction pressure of the particulate gas 31 is set to less than 1 Pa including the 0 Pa state, the particulate gas 31 may be water vapor as well as glycol alcohol vapor, smoke such as fragrance, etc. Any diameter may be used.

  On the upper end portion 13 of the porous body 10, a light generating means 40 for irradiating light 41 having strong directivity such as laser light is disposed. Light 41 from the light generating means 40 is irradiated almost in parallel with the upper end portion 13 of the porous body 10, and the irradiation position height H with respect to the upper end portion 13 of the porous body 10 is preferably 3 to 5 mm. As will be described later, the light 41 is irradiated onto the fine particle gas 31 derived from the upper end portion 13 of the porous body 10 to visualize the fine particle gas.

  The light generating means 40 is set so as to irradiate light 41 in a planar shape parallel to the surface of the upper end portion 13 of the porous body 10. The wavelength of the light 41 is 100 to 1,000,000 nm (nanometers) and can be visualized by setting within this range, preferably 300 to 4,000 nm, and more preferably 400 to 700 nm.

  A camera 50 for recording the visualized particulate gas 31 is disposed on the light generating means 40. The camera 50 crosses the light 41 at the upper end 13 of the porous body 10 from above so that the line of sight 51 faces the irradiation direction of the irradiation line of the light 41 at a predetermined angle (0 ° to 90 °). It is attached to. If the line of sight 51 of the camera 50 is set so as to face the irradiation line of the light 4, the visualization accuracy is improved as compared with the forward direction.

  Next, an inspection method in which the introduction pressure of the particulate gas 31 is set to less than 1 Pa (including the 0 Pa state) in the inspection method of the present invention will be described with reference to FIGS. FIG. 2 shows a case where a defect (pore diameter of about 0.1 mm) 17 is present on the lower end 12 side (inlet side) of the porous body 10 that is an object to be inspected, and FIG. The case where it exists in the part 13 side (exit side) is shown.

  First, the detection state when the defect 17 exists on the lower end portion 12 side of the porous body 10 will be described. The glycol-based alcohol vapor as the particulate gas 31 generated in the particulate gas generating means 30 and filling the chamber 21 forming the particulate gas introducing means 20 is raised from the cell hole 11 at the lower end portion 12 of the porous body 10 by the rising force. It is introduced from the A direction. When the fine particle gas 31 is introduced with its ascending force, the introduction pressure is 0 Pa, but the fine particle gas 31 may be introduced at a pressure of less than 1 Pa. Here, the introduction pressure of the particulate gas 31 means the pressure on the lower end portion 12 side with respect to the upper end portion 13 side of the porous body 10, that is, the differential pressure between the upper end portion 13 side and the lower end portion 12 side (the lower end portion 12 side is high). The 0 Pa state means a state in which the differential pressure between the upper end 13 side and the lower end 12 side is zero.

  Since the defect 17 exists on the lower end 12 side of the porous body 10, the particulate gas 31 is not affected by the detection rate even if the introduction pressure exceeds 1 Pa as described in FIG. Therefore, the defect 17 having a small ventilation resistance flows as shown by an arrow B and is led out from the upper end 13 side of the porous body 10. At this time, since the ventilation resistance is large from the fine hole 16 on the lower end 12 side, the particulate gas does not flow at a low pressure of less than 1 Pa.

  The particulate gas derived from the upper end portion 13 side is irradiated with light 41 having strong directivity generated from the light generating means 40 and emits light to be visualized. The emission state of the particulate gas 31 visualized by light emission is recorded by the camera 50, and the presence of the defect 17 can be detected. Since the light 41 is irradiated in a planar shape, the visualization state of the particulate gas can be viewed two-dimensionally, and the position of the defect 17 on the plane can be detected more reliably on the lower end 12 side.

  Next, a detection state when the defect 17 exists on the upper end portion 13 side of the porous body 10 will be described with reference to FIG. Glycol-based alcohol vapor as fine particle gas 31 generated by the fine particle gas generating means 30 and filled in the chamber 21 is introduced from the cell hole 11 at the lower end portion 12 of the porous body 10 from the direction of arrow A by its ascending force. When the fine particle gas 31 which is glycol alcohol vapor is introduced by its ascending force, the introduction pressure is 0 Pa, but the fine particle gas 31 may be introduced at a pressure of less than 1 Pa. Even when the defect 17 is present on the upper end 13 side of the porous body 10, since the introduction pressure of the fine particle gas 31 is a low pressure of less than 1 Pa, the fine particle gas 31 is present from the lower end 12 side to the upper end 13 side. Since the air flow resistance is large from the hole 16, it does not flow, and the particulate gas 31 flows through the defect 17 on the upper end 13 side of the porous body 10 as shown by the arrow B as described with reference to FIG. To derive.

  The particulate gas 31 led out from the upper end 13 side is irradiated with light 41 having strong directivity generated from the light generating means 40 and emits light to be visualized. The emission state of the particulate gas visualized by light emission is recorded by the camera 50, and the presence of the defect 17 can be detected.

  In the present invention, since the detection of the defect is made possible by setting the introduction pressure of the particulate gas 31 to less than 1 Pa as described above, if the particulate gas 31 to be introduced has a particle size in the range of 1 to 10 μm, the glycol system is used. It is not limited to alcohol vapor, and may be fine particle gas such as smoke caused by steam or fragrance combustion.

  Further, in the present invention, since the introduction pressure of the particulate gas 31 is set to be less than 1 Pa as described above, there is almost no difference in the introduction pressure distribution in the length L direction of the porous body 10 that is the inspection body. Since the difference in the introduction pressure distribution increases as the length L of the porous body 10 increases, the effect is exhibited when the length L of the porous body 10 is long if the introduction pressure is set to a low pressure of less than 1 Pa. Therefore, even if the porous body 10 has a length of about 600 mm, the defect 17 on the upper end portion 13 side can be detected accurately and reliably. Further, if the introduction pressure of the fine particle gas 31 is introduced by the ascending force of the fine particle gas 31 in the state of 0 Pa, no pressure distribution is generated, and there is no circulation of the fine particle gas 31 from the fine holes 16, so that the defect 17 is further improved. It can be detected with high accuracy.

  Further, in the inspection method of the present invention, when the fine particle gas is heated and the glycol alcohol vapor (propylene glycol) is heated to a temperature of 400 ° C. or lower as described above, the glycol alcohol vapor carbon is introduced. Almost no thermal decomposition, therefore carbon is not activated, and the dispersion of the glycol alcohol vapor can be made uniform by preventing the carbon from agglomerating and becoming large glycol alcohol vapor, thereby preventing variation in inspection accuracy. At the same time, dropping by large particles can be suppressed. The degree of the drop of the large particles increases as the length L (height) of the porous body 10 increases. Therefore, the effect is exhibited when the length L of the porous body 10 is long. Therefore, even if the length L of the porous body 10 is about 600 mm, the defect 17 on the upper end 13 side can be detected. In this case, the introduction pressure of the glycol alcohol vapor is preferably less than 1 Pa, but is not limited thereto.

  Moreover, it is desirable that the glycol alcohol vapor works with water vapor generated from atmospheric water or distilled water (dissolves in the water vapor), so that a stable glycol alcohol vapor can be obtained. Note that it is not always necessary to react with water vapor, and it may be heated and vaporized only with glycol-based alcohol and then vaporized.

  In the above-described inspection method in which the introduction pressure of the fine particle gas 31 is set to less than 1 Pa and the inspection method in which the fine particle gas 31 is heated at a temperature of 400 ° C. or less to produce glycol alcohol vapor, the following methods are used. The defect can be detected with higher accuracy.

  If the volume of the particulate gas 31 is filled in the porous body 10 by more than half of the volume of the porous body 10, the amount necessary for visualization of the particulate gas 31 circulates in the defect 17 and is visualized by the directional light 41. Can be reliably performed and inspection accuracy is improved.

  Further, if the light 41 is irradiated in a planar shape, the visualization state of the particulate gas 31 can be viewed two-dimensionally, so that the position of the defect 17 on the plane can be detected more reliably on the lower end 12 side.

  Moreover, since the wavelength of the light 41 is set to 100 to 1,000,000 nm, the visualization of the particulate gas 31 can be realized with certainty.

  Further, if a honeycomb structure for a diesel particulate filter is used as the porous body 10 in the present invention, it is suitable for the structure of the porous body in the present invention, and the effect of detecting defects is maximized.

  In the present invention, the porous body as the detection target may be a porous body other than the DPF honeycomb structure, and can also be applied to a non-porous body.

  Moreover, the defect of a porous body is not restrict | limited to said pore diameter and shape.

It is a schematic diagram of the inspection apparatus which uses for description of this invention inspection method and implements this invention inspection method. FIG. 5 is an enlarged cross-sectional view when the defect 17 is present on the lower end 12 side of the porous body 10 for explaining the inspection method of the present invention. FIG. 5 is an enlarged cross-sectional view when the defect 17 is present on the upper end portion 13 side of the porous body 10 for explaining the inspection method of the present invention. FIG. 5 is a graph illustrating a particle size distribution 10 seconds after generation of glycol alcohol vapor, which is used for explaining the inspection method of the present invention. 7 is a graph showing the particle size distribution 50 seconds after the generation of glycol alcohol vapor, which is used for explaining the inspection method of the present invention. It is for use in the description of the inspection method of the present invention, and is a graph showing the relationship of the detection rate to the fine particle diameter. FIG. 5 is a graph for explaining the inspection method of the present invention, and showing the relationship between the introduction pressure of the particulate gas and the defect detection rate using the position where the defect exists as a parameter. It is a graph which shows the fine particle diameter distribution 10 seconds after burning and producing | generating fragrance | flavor in the conventional inspection method. It is a graph which shows fine particle size distribution 50 seconds after burning and producing | generating fragrance | flavor in the conventional inspection method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Porous body 11 Cell hole 12 Lower end part 13 Upper end part 14 Partition 15 Plug 16 Micro hole 17 Defect 20 Particulate gas introduction means 21 Chamber 30 Particulate gas generation means 31 Particulate gas 40 Light generation means 41 Light 50 Camera 51 Camera 50 line of sight L Axial length of porous body 10

Claims (20)

A fine particle gas having a diameter of 1 to 10 μm is introduced from the lower end of the porous body,
Generating highly directional light substantially parallel to the upper end of the porous body;
A method for inspecting a porous body, wherein the light is irradiated with the particulate gas discharged from the upper end portion of the porous body to visualize the particulate gas and detect a defect in the porous body,
A method for inspecting a porous body, wherein the fine particle gas is introduced from the lower end of the porous body at less than 1 Pa to detect a defect in the porous body.   The method for inspecting a porous body according to claim 1, wherein the introduction of the particulate gas from the lower end portion of the porous body at less than 1 Pa is caused to be introduced by the ascending force of the particulate gas itself in a 0 Pa state.   3. The method for inspecting a porous body according to claim 1, wherein the fine particle gas is glycol alcohol vapor generated by heating glycol alcohol at a temperature of 400 ° C. or lower. A fine particle gas having a diameter of 1 to 10 μm is introduced from the lower end of the porous body,
Generating highly directional light substantially parallel to the upper end of the porous body;
A method for inspecting a porous body, wherein the light is irradiated with the particulate gas discharged from the upper end portion of the porous body to visualize the particulate gas and detect a defect in the porous body,
A method for inspecting a porous body comprising detecting a defect in the porous body by introducing a glycol-based alcohol vapor generated by heating the particulate gas at a temperature of 400 ° C. or less and introducing the glycol-based alcohol vapor. .   5. The method for inspecting a porous body according to claim 3, wherein the glycol alcohol vapor is allowed to act on water vapor.   The method for inspecting a porous body according to any one of claims 1 to 5, wherein the fine particle gas is filled in the porous body at least half the volume of the porous body.   The length from the lower end part of the said porous body to an upper end part is 10-600 mm, The inspection method of the porous body as described in any one of Claims 1-6 characterized by the above-mentioned.   The method for inspecting a porous body according to claim 1, wherein the defect is detected two-dimensionally or one-dimensionally by generating the light in a planar shape.   The method for inspecting a porous body according to any one of claims 1 to 8, wherein the wavelength of the light is 100 to 1,000,000 nm.   The said porous body is a honeycomb structure for diesel particulate filters, The inspection method of the porous body as described in any one of Claims 1-9 characterized by the above-mentioned. Fine particle generation means for generating a fine particle gas having a diameter of 1 to 10 μm;
A particulate gas introducing means for introducing the particulate gas generated by the particulate gas generating means from the lower end of the porous body;
Light generating means for irradiating the particulate gas emitted from the upper end of the porous body so as to make the particulate gas visible by generating light having high directivity substantially parallel to the upper end of the porous body A porous body inspection apparatus comprising:
The inspection apparatus for a porous body, wherein the particulate gas introduction means is a means for introducing the particulate gas from the lower end of the porous body at less than 1 Pa.   12. The inspection apparatus for a porous body according to claim 11, wherein the introduction of the particulate gas from the lower end portion of the porous body at less than 1 Pa is introduced by the ascending force of the particulate gas itself in a 0 Pa state.   13. The inspection apparatus for a porous body according to claim 11 or 12, wherein the fine particle gas generating means is means for generating glycol alcohol vapor by heating glycol alcohol at a temperature of 400 ° C. or lower. Fine particle generation means for generating a fine particle gas having a diameter of 1 to 10 μm;
A particulate gas introducing means for introducing the particulate gas generated by the particulate gas generating means from the lower end of the porous body;
Light generating means for irradiating the particulate gas emitted from the upper end portion of the porous body so as to make the particulate gas visible by generating light having high directivity substantially parallel to the upper end portion of the porous body. A porous body inspection apparatus comprising:
The fine particle generating means is a means for generating glycol alcohol vapor by heating glycol alcohol at a temperature of 400 ° C. or lower.   15. The inspection apparatus for a porous body according to claim 13, wherein the glycol-based alcohol vapor is allowed to act on water vapor.   16. The chamber according to claim 11, wherein the particulate gas introduction means is provided with a chamber that fills the porous body with the particulate gas volume of at least half of the volume of the porous body. The inspection apparatus for porous bodies according to 1.   The length from the lower end part of the said porous body to an upper end part is 10-600 mm, The inspection apparatus of the porous body as described in any one of Claims 11-16 characterized by the above-mentioned.   The said light generation means is a means to generate | occur | produce the said light planarly, The inspection apparatus of the porous body as described in any one of Claims 11-17 characterized by the above-mentioned.   The inspection apparatus for a porous body according to any one of claims 11 to 18, wherein the wavelength of the light is 100 to 1,000,000 nm. The said porous body is a honeycomb structure for diesel particulate filters, The inspection apparatus of the porous body as described in any one of Claims 11-19 characterized by the above-mentioned.