JP3839177B2 - Pinhole inspection device for porous ceramic members - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inspection device for detecting pinholes in a porous ceramic member partition wall.
[0002]
[Prior art]
Recently, it has been a problem that particulates contained in exhaust gas discharged from internal combustion engines such as vehicles such as buses and trucks and construction machines cause harm to the environment and the human body.
Various ceramic filters that purify exhaust gas by collecting particulates in the exhaust gas by passing the exhaust gas through a porous ceramic have been proposed.
[0003]
The porous ceramic member 10 has a large number of through holes 11 arranged in the longitudinal direction, and a partition wall 13 that separates the through holes 11 functions as a filter.
That is, as shown in FIG. 1B, the through-hole 11 formed in the porous ceramic member 10 is sealed with the filler 12 at either the exhaust gas inlet side or the outlet side end. The exhaust gas that has flowed into the through-hole 11 always passes through the partition wall 13 separating the through-holes 11 and then flows out from the other through-holes 11. When the exhaust gas passes through the partition wall 13, the particulates Is captured by the partition wall 13 and the exhaust gas is purified.
At this time, if the pinhole 14 exists in the partition wall 13, the particulates pass through the pinhole 14, and the ceramic filter using such a porous ceramic member 10 cannot sufficiently purify the exhaust gas. .
[0004]
Therefore, before manufacturing the ceramic filter, it must be confirmed that the pinhole 14 does not exist in the partition wall 13.
Conventionally, as a method for confirming the presence or absence of such pinholes, a method of irradiating the porous ceramic member 10 with X-rays and confirming the presence or absence of pinholes from the transmittance of the X-rays has been used.
[0005]
However, in the method using X-rays, if the thickness of the partition wall 33 is different as shown in FIG. 3, the change in the transmittance due to the presence of the pinhole 34 can be detected because the X-ray transmittance is different. could not. That is, even when the pinhole 34 exists in the partition wall 33, if the thick partition wall portion 33 a exists in the X-ray irradiation direction of the pinhole 34, the increase in transmittance due to the presence of the pinhole 34 increases the thickness of the thick partition wall portion 33 a. This is offset by a decrease in transmittance due to the presence. As a result, there is a problem that the presence of the pinhole 34 may not be detected.
Further, as shown in FIG. 4, since X-rays spread radially, the end portions and the central portion of the partition wall 43 constituting the porous ceramic member 40 have different thicknesses in the X-ray irradiation direction and the same thickness. Regardless of the partition wall 43 having a thickness, the measured transmittance is different. Therefore, the detection of the pinhole 44 can be performed only in a spot portion, and there is a problem that productivity is poor.
[0006]
[Problems to be solved by the invention]
Things present invention has been made in order to solve these problems, that can detect a pin hole of the partition walls of the porous ceramic member accurately, and an object thereof is to provide an inspection apparatus of the porous ceramic member It is.
[0008]
[Means for Solving the Problems]
The porous ceramic member pinhole inspection apparatus according to the present invention includes a gas blowing portion, a powder storage portion for storing inspection powder, and a ceramic member mounting portion for mounting a porous ceramic member for inspection. And a detection unit for detecting the powder mixed in the gas, and further, during the inspection, the gas blown from the gas blowing unit is allowed to pass through the powder storage unit, thereby the inspection powder. The body is guided to the porous ceramic member mounted on the ceramic member mounting portion together with the gas, and a pipe for guiding the gas discharged from the other end of the ceramic member mounting portion to the detection portion, and after the inspection is completed, The gas blown from the gas blowing portion is guided to the other end of the ceramic member mounting portion, and the inspection powder captured by the porous ceramic member is powdered together with the gas. It and a pipe for returning the housing part and is characterized in.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a pinhole inspection method and a pinhole inspection apparatus for a porous ceramic member according to the present invention will be described with reference to the drawings.
[0010]
A pinhole inspection method for a porous ceramic member according to the present invention is a pinhole inspection method for detecting a pinhole in a partition wall separating a through hole of a porous ceramic member using a powder having a constant particle diameter, The porous ceramic member has a large number of through-holes arranged in the longitudinal direction thereof, one end of the through-hole is filled with a filler in a checkered pattern, and the other end is filled with a filler at one end. Is a columnar porous ceramic member filled with a filler in a through hole not filled with, the detection of pinholes in the partition wall does not pass through the pores formed in the porous ceramic member, and The method is characterized in that after a gas mixed with a powder having a recoverable size is introduced from one end of the through hole, the powder discharged from the other end is detected by a detection device. To do.
[0011]
First, a porous ceramic member to be inspected in the present invention will be described with reference to FIGS. 1 (a) and 1 (b).
Fig.1 (a) is a perspective view which shows one form of the said porous ceramic member, FIG.1 (b) is the sectional view on the AA line of Fig.1 (a).
As shown in FIG. 1A, the porous ceramic member has a large number of through holes 11 arranged in the longitudinal direction, and one end of the through hole 11 is filled with a filler 12 in a checkered pattern. And the other end is a columnar one in which the filler 12 is filled in the through hole 11 in which the filler 12 is not filled in the one end.
Inside the porous ceramic member, a partition wall 13 is formed as shown in FIG. For this reason, the gas flowing into one through-hole 11 always passes through the partition wall 13 separating the through-holes 11 and then flows out from the other through-holes 11. When there is a substance that cannot pass through, the substance that cannot pass through the partition wall 13 is captured by the partition wall 13 when the gas passes through the partition wall 13.
In addition, the porous ceramic member 10 shown in FIG. 1A has a quadrangular prism shape, but the shape of the porous ceramic member to be subjected to the pinhole inspection is not limited to the quadrangular prism shape, and a triangular prism or five It may have a prismatic shape or a cylindrical shape.
[0012]
The porous ceramic member 10 is prepared, for example, by preparing a mixed composition of a ceramic powder, a binder, and a dispersion medium, and then molding the obtained mixed composition using an extruder, and drying the obtained molded body. It is prepared by degreasing and firing.
The ceramic powder is not particularly limited, and examples thereof include non-oxide ceramic powders such as silicon carbide, silicon nitride, aluminum nitride, boron nitride, titanium nitride, and titanium carbide; alumina, cordierite, mullite, silica, zirconia, Examples thereof include oxide ceramic powders such as titania.
[0013]
Next, the pinhole inspection method of the present invention will be described with reference to FIG.
In the pinhole inspection method of the present invention, a gas mixed with powder 15 is introduced from one end of through-hole 11, and then powder 15 in the gas discharged from the other end of through-hole 11 is detected by a detection device. Thus, the presence or absence of the pinhole 14 is inspected.
[0014]
That is, when the pinhole 14 exists in the partition wall 13, the powder introduced from one end portion of the through hole 11 passes through the pinhole 14 and is then discharged together with the gas from the other end portion of the through hole 11. (Flow path α). Therefore, pinholes can be detected by detecting the powder in the gas with a detection device.
[0015]
On the other hand, when the pinhole 14 does not exist in the partition wall 13, the powder 15 introduced from one end portion of the through hole 11 cannot pass through the partition wall 13, and therefore, from the other end portion of the through hole 11. The powder 15 is not mixed in the discharged gas (flow path β). Therefore, it can be seen that no powder is detected even if the discharged gas is introduced into the detection device, and no pinhole 14 exists in the partition wall 13.
By performing the pinhole inspection method, it is possible to inspect whether or not there is a pinhole in the partition wall 13 of the porous ceramic member 10.
[0016]
The material of the powder 15 is not particularly limited, and examples thereof include inorganic compounds such as glass, organic compounds such as resins, metals, and the like.
If the particle size of the powder 15 is constant, the size thereof is not particularly limited, and may be appropriately set according to the size of the pinhole to be inspected. For example, the exhaust gas using the porous ceramic member 10 In the case of producing a ceramic filter that purifies the water, a powder having a particle size of 50 to 60 μm is used in consideration of the required performance of the ceramic filter. In the present specification, the powder having a constant particle size does not mean that all the powders have the same particle size, but means that the powder has a narrow particle size distribution. Examples thereof include JIS test powder II made of glass beads, white fused alumina, or the like described in JIS Z 8901.
[0017]
The detection device is not particularly limited as long as it can determine the presence / absence of powder, but a particle counter is preferable because it can easily determine the presence / absence of powder.
This particle counter crosses a gas containing fine particles that pass through a narrow space with light from a laser or the like, and measures the intensity of light scattered by the fine particles generated at that time using a so-called light scattering method. This is a device for measuring the size, and by introducing the gas in which the fine particles are suspended into the particle counter, the number of fine particles can be continuously measured, so that it has excellent immediate response.
Therefore, by directing the gas discharged after passing through the partition wall 13 directly to the particle counter, it is possible to inspect whether powder is mixed in the gas and to determine the presence or absence of a pinhole.
[0018]
The pinhole inspection method of the present invention, as described above, determines whether or not a pinhole is present depending on whether or not the powder has passed through the porous ceramic member. Since it can be measured in time, it has advantages such as high productivity, low maintenance cost, and inspection powder can be reused.
[0019]
Next, a pinhole inspection apparatus for a porous ceramic member according to the present invention will be described with reference to FIG.
The porous ceramic member pinhole inspection apparatus according to the present invention includes a gas blowing portion, a powder storage portion for storing inspection powder, and a ceramic member mounting portion for mounting a porous ceramic member for inspection. And a detection unit for detecting the powder mixed in the gas, and further, during the inspection, the gas blown from the gas blowing unit is allowed to pass through the powder storage unit, thereby the inspection powder. The body is guided to the porous ceramic member mounted on the ceramic member mounting portion together with the gas, and a pipe for guiding the gas discharged from the other end of the ceramic member mounting portion to the detection portion, and after the inspection is completed, The gas blown from the gas blowing portion is guided to the other end of the ceramic member mounting portion, and the inspection powder captured by the porous ceramic member is powdered together with the gas. And a pipe for returning the housing portion.
[0020]
FIG. 2 is an explanatory view showing an embodiment of a pinhole inspection apparatus for a porous ceramic member of the present invention.
The pinhole of the porous ceramic member to be inspected in the pinhole inspection apparatus for the porous ceramic member of the present invention is the same as that described in the method for inspecting the porous ceramic member of the present invention.
As shown in FIG. 2, the pinhole inspection device 20 for a porous ceramic member according to the present invention includes a gas blowing portion 21, a powder storage portion 22 for storing inspection powder, and a porous body for inspection. A ceramic member mounting portion 23 for mounting the ceramic member and a detection portion 24 for detecting powder mixed in the gas are provided.
[0021]
The gas blowing part 21 is not particularly limited as long as gas can be blown, and examples thereof include an air pump. Moreover, although the gas blown in is not specifically limited, Usually, air (dry air) is used.
The amount of gas fed from the gas blowing section 21 is not particularly limited, and may be set according to the shape of the porous ceramic member to be inspected, and is usually preferably set to 20 to 40 l / min.
[0022]
The powder storage unit 22 is a member for storing the inspection powder, and is removable. The powder storage unit 22 may be attached after the inspection powder is stored therein.
The powder storage unit 22 not only stores the inspection powder at the time of inspection, but also has a role of collecting the inspection powder for reuse after the end of the inspection. Therefore, usually, after the inspection is performed, the inspection powder can be collected, so that the inspection can be performed any number of times using the same inspection powder.
[0023]
Therefore, a filter (not shown) is provided at the end of the powder storage unit 22 on the side of the valve 25 so that the inspection powder can be collected when the inspection powder to be described later is collected. The filter is not particularly limited as long as the filter has an opening smaller than the particle size of the detection powder and is configured to prevent the powder from clogging.
[0024]
The ceramic member mounting portion 23 is a portion for mounting the porous ceramic member 10 to be inspected according to the present invention during inspection.
The ceramic member mounting portion 23 is configured so that the gas blown into the porous ceramic member does not leak to the outside by mounting the porous ceramic member 10 to be inspected. That is, for example, if a pair of mask-like mounting tools 23a and 23b as shown in FIG. 2 are mounted on both ends of the porous ceramic member 10, the gas blown into the porous ceramic member 10 leaks to the outside. There is no such thing. Further, the porous ceramic member 10 is sequentially transported to the vicinity of the mounting tools 23a and 23b, and the mounting tools 23a and 23b are automatically mounted by a signal from the sensor that detects the porous ceramic member 10. It has become.
[0025]
The ceramic member mounting portion 23 may have a container shape that can accommodate the porous ceramic member 10. In this case, it is desirable that an elastic body or the like is attached to the inside of the storage container so that the gas does not pass outside the porous ceramic member 10 when the porous ceramic member 10 is stored.
The detection unit 24 includes a detector, and the detector is not particularly limited, but a particle counter is preferable.
[0026]
Furthermore, the pinhole inspection apparatus 20 for a porous ceramic member according to the present invention allows the gas blown from the gas blowing portion 21 to pass through the powder storage portion 22 during the inspection, thereby allowing the inspection powder together with the gas to the ceramic member. A pipe for guiding the gas discharged from the other end of the ceramic member mounting portion 23 to the detection portion 24 while being guided to the porous ceramic member 10 mounted on the mounting portion 23, and blown from the gas blowing portion 21 after completion of the inspection. And a pipe for guiding the gas to the other end of the ceramic member mounting portion 23 and returning the inspection powder captured by the porous ceramic member 10 to the powder storage portion 23 together with the gas.
[0027]
Specifically, as shown in FIG. 2, the pipe exiting from the gas blowing section 21 branches in two directions in the middle, and the pipe branched to the left side in the figure includes the three-way valve 25, the powder storage section 22 and The valve 26 is connected to the mounting tool 23 a, and further branches after passing through the valve 26, and is connected to the detection unit 24 via the valve 28.
[0028]
Further, in the drawing, the pipe branched to the right side is connected to the mounting portion 23 b via the valve 27, further branched after passing through the valve 27, and connected to the detection portion 24 via the valve 29. That is, the pipe passing through the valve 28 and the pipe passing through the valve 29 become one pipe on the way and are connected to the detection unit 24.
Further, another pipe coming out from the detection unit 24 is connected to a pipe between the powder storage unit 22 and the valve 26, and a discharge pipe having a valve 201 is connected to the middle of this pipe. Yes. Note that a filter (not shown) is provided at the branch port of the discharge pipe so that the powder does not leak outside.
[0029]
Next, a pinhole inspection method using the inspection apparatus of the present invention will be described.
First, the three-way valve 25 is in a state in which gas passes through pipes connected to both ends, the valves 26, 29, and 201 are in an open state, and the valves 27, 28, and 202 are in a closed state. Thereby, a gas such as air blown from the gas blowing section 21 is guided to the porous ceramic member 10 through the flow paths a and b, further passed through the flow path e and guided to the detection section 24, and then the valve It is discharged to the outside through 201.
[0030]
At this time, since the gas passes through the powder storage unit 22, the inspection powder in the powder storage unit 22 is guided to the porous ceramic member 10 together with the gas. When no pinholes are present in the partition walls of the porous ceramic member 10, since the whole amount of the inspection powder is captured by the partition wall portions, no powder is detected by the detection unit 24.
On the other hand, if the partition wall is present in the pinhole, a part of the inspection powder reaches the detection unit 24 via the flow path e, and thus the inspection powder is detected by the detection unit.
However, since the discharge pipe is provided with a filter, the inspection powder is collected by this filter.
[0031]
After the inspection is completed, the three-way valve 25 is in a state where the piping on the powder container 22 side is electrically connected to the outside, the valves 26, 29, 201 are closed, and the valves 27, 28, 202 are opened. In this state, gas is blown, and the gas passes through the flow paths a and c to be guided to the porous ceramic member 10. As a result, the gas flows into the porous ceramic member 10 from the direction opposite to the direction in which the gas or the like first passes, so that the inspection powder captured by the porous ceramic member 10 flows out into the pipe together with the gas. After passing through the path d, the detection unit 24, and the flow path f, the powder is collected by the filter of the powder storage unit 21 and returns to the powder storage unit 21. Thereafter, the gas is discharged to the outside through the three-way valve 25. Even when the inspection powder is collected in the filter of the discharge pipe, it is recovered at the time of the powder recovery.
[0032]
As described above, the pinhole inspection apparatus for porous ceramic members according to the present invention can detect a pinhole that cannot be detected by X-ray irradiation because it determines the presence or absence of a pinhole based on the presence or absence of the passage of powder. it can. Also, unlike destructive inspection, 100% inspection can be performed. In addition, after introducing the gas and the inspection powder from the through hole, the presence or absence of the inspection powder is immediately determined by the detection unit, so that productivity is high.
[0033]
The inspection apparatus of the present invention is configured such that operations such as mounting of a porous ceramic member to a ceramic mounting portion, switching of a valve, blowing of gas, etc. can be performed by transmitting a signal from the control device. . In addition, the control device stores information on sensors for detecting whether or not each operation has been performed and operation procedure information. By operating this control device, pinhole inspection of the porous ceramic member is performed. It is possible to automatically perform the pinhole inspection of the porous ceramic member.
[0034]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0035]
Example 1
After kneading by adding an organic binder, water, etc. to silicon carbide powder, extrusion molding is performed to produce a honeycomb-shaped molded body, followed by drying, degreasing, and firing to obtain an average as shown in FIG. A porous ceramic member having a pore diameter of 5 to 20 μm, 200 cells per square inch, and a partition wall thickness of 0.3 mm was produced.
[0036]
Next, the obtained porous ceramic member is inspected for the presence or absence of pinholes using the porous ceramic member pinhole inspection apparatus 20 shown in FIG. Sorted into no porous ceramic members.
[0037]
Thereafter, each porous ceramic member was cut along the through hole in the longitudinal direction to obtain a measurement sample having one layer of partition walls. Then, the measurement sample was gradually moved while irradiating the obtained measurement sample with X-rays, and it was measured whether or not there was a pinhole in the partition wall.
[0038]
As a result, in the porous ceramic member in which no pinhole was detected in the measurement by the pinhole inspection method of the porous ceramic member of the present invention, no pinhole was detected in the measurement by X-ray irradiation. Further, in the porous ceramic member in which pinholes were detected in the method for inspecting a pinhole of a porous ceramic member according to the present invention, pinholes were also detected in measurement by X-ray irradiation.
[0039]
Comparative Example 1
For a porous ceramic member obtained by using the same method as in Example 1, instead of the pinhole inspection method of the present invention, the presence or absence of pinholes is inspected by irradiating with X-rays, and a porous material having pinholes Whether or not there is a pinhole in the partition wall was measured in the same manner as in Example 1 except that the porous ceramic member was separated into a porous ceramic member and a porous ceramic member without a pinhole.
[0040]
As a result, in the porous ceramic member in which pinholes were detected in the measurement by X-ray irradiation before cutting, pinholes were detected in the measurement by X-ray irradiation after cutting, but measurement by X-ray irradiation before cutting Among the porous ceramic members in which no pinholes were detected, there were those in which pinholes were detected in the measurement by X-ray irradiation after cutting.
Therefore, it has been found that the pinhole cannot be reliably detected by the method of inspecting the pinhole without cutting the porous ceramic member.
[0041]
【The invention's effect】
Since the method for inspecting a pinhole of a porous ceramic member according to the present invention is as described above, the pinhole in the partition wall of the porous ceramic member can be accurately detected, and the productivity is high.
[0042]
Moreover, since the pinhole inspection apparatus for porous ceramic members of the present invention is as described above, by using this inspection apparatus, pinholes in the partition walls of the porous ceramic member can be formed with high accuracy and high productivity. Can be detected.
[Brief description of the drawings]
FIG. 1A is a perspective view showing one embodiment of a method for drying a porous ceramic member to be inspected according to the present invention, and FIG. 1B is a sectional view taken along line AA in FIG. It is.
FIG. 2 is an explanatory view schematically showing an embodiment of a pinhole inspection apparatus for a porous ceramic member of the present invention.
FIG. 3 is an enlarged cross-sectional view of a main part for explaining detection of pinholes by X-ray irradiation performed conventionally.
FIG. 4 is a cross-sectional view schematically showing an embodiment of pinhole detection by X-ray irradiation that has been conventionally performed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Porous ceramic member 11 Through-hole 12 Filler 14 Pinhole 15 Powder 20 Porous ceramic member pinhole inspection apparatus 21 Gas blowing part 22 Powder storage part 23 Ceramic member mounting part 24 Detection part

Claims (3)

  A gas blowing section, a powder storage section for storing inspection powder, a ceramic member mounting section for mounting a porous ceramic member to be inspected, and for detecting powder mixed in the gas And a gas blown from the gas blowing part at the time of inspection to pass through the powder storage part, thereby mounting the inspection powder together with the gas on the ceramic member mounting part. A pipe for guiding the gas discharged from the other end of the ceramic member mounting portion to the detection portion while leading to the porous ceramic member, and the gas blown from the gas blowing portion after the inspection is finished, the ceramic member mounting portion And a pipe for returning the inspection powder captured by the porous ceramic member together with the gas to the powder storage unit. Pinhole inspection apparatus of the porous ceramic member. The test powder, the porous does not pass through the pores formed in the ceramic member, and, pinhole inspection apparatus of the porous ceramic member according to claim 1, wherein the powder of the recoverable size. The pinhole inspection apparatus for a porous ceramic member according to claim 1 or 2 , wherein the powder has a particle size of 50 to 60 µm.

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