JP2012083258A - Defect inspection method and defect inspection device for honeycomb filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defect inspection method and a defect inspection device for a honeycomb filter capable of an inspection in a short time.SOLUTION: The defect inspection method for a honeycomb filter comprises: a step of supplying gas to one end surface 100b of a honeycomb filter 100 comprising partition walls 112 forming multiple flow paths 110 from the one end surface 100b to the other end surface 100t and sealing parts 114 for closing either end of the multiple flow paths 110; a step of supplying the gas exhausted from the other end surface 100t of the honeycomb filter 100 to a gas receiving member 10 which is arranged so as to face the other end surface 100t and is heated; and a step of measuring temperature distribution of the gas receiving member 10.

Description

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

  Conventionally, a defect inspection method for a honeycomb filter used as a diesel particulate filter is known. For example, Patent Document 1 discloses a method of supplying a gas flow having a high temperature of about 140 ° C. to the inlet end face of a honeycomb filter and measuring the temperature of the outlet end face of the honeycomb filter with an infrared camera.

JP 2008-58119 A

  However, the conventional method has the following problems. That is, since the honeycomb filter is made of ceramics, its thermal conductivity is poor, and it takes several tens of seconds or more after the gas starts to be supplied to the inlet end face until the temperature of the outlet end face of the honeycomb filter changes. Furthermore, since the honeycomb filter is at a high temperature after the measurement, it takes a long time to cool the heated honeycomb filter before performing the post-process.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for inspecting a honeycomb filter for a defect and an inspection device for a honeycomb filter defect, which can be inspected in a short time. .

The honeycomb filter defect inspection method according to the present invention,
A step of supplying gas to the one end face of the honeycomb filter having a partition wall that forms a plurality of flow paths from one end face to the other end face, and a sealing portion that closes one end of each of the flow paths;
Supplying the gas discharged from the other end surface of the honeycomb filter to the gas receiving member, which is disposed so as to face the other end surface and heated;
Measuring a temperature distribution of the gas receiving member.

A defect inspection apparatus for a honeycomb filter according to the present invention,
A partition that forms a plurality of flow paths from one end face to the other end face, and a supply section that supplies gas to one end face of the honeycomb filter having a sealing portion that closes one end of each flow path,
A gas receiving member disposed to face the other end surface of the honeycomb filter;
A heater for heating the gas receiving member;
A temperature measuring unit that measures a temperature distribution of the gas receiving member.

  According to the present invention, since a larger amount of gas flows out from a flow path having a defective part such as a partition defect, compared to other normal parts, the temperature of the part of the gas receiving member facing the part is different. Lower than the part of. Therefore, by detecting the temperature drop portion of the gas receiving member, the defect of the honeycomb filter can be quickly measured, and the honeycomb filter is not unnecessarily heated.

  Here, it is preferable to measure the temperature distribution of the gas receiving member with an infrared camera. According to this, the temperature distribution can be easily measured.

  The gas receiving member preferably has a plurality of holes so as to allow gas to pass therethrough, and is particularly preferably a metal net, a metal porous plate, or a metal porous plate.

  Further, the gas supplied to one end face of the honeycomb filter is preferably a gas of 50 ° C. or lower.

  ADVANTAGE OF THE INVENTION According to this invention, the method for inspecting the defect of a honey-comb filter which can be test | inspected in a short time, and the inspection apparatus of the defect of a honey-comb filter are provided.

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 showing an embodiment of the gas flow detection unit 50 of the apparatus 400 of FIG. FIG. 4 is a top view showing another form of the gas flow detection unit 50 of the apparatus 400 of FIG. FIG. 5 is a top view showing another form of the gas flow detection unit 50 of the apparatus 400 of FIG. 6A and 6B are examples of temperature distribution images of the gas receiving member measured by the infrared camera of the apparatus 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 a partition wall 112 that forms a plurality of flow paths 110 extending in parallel from one end surface 100b to the other end surface 100t. And one end of a part of the plurality of flow paths 110 (left end of FIG. 1B) and the other end of the remaining part of the plurality of flow paths 110 (right end of FIG. 1B). It is a cylinder which has the sealing part 114 which closes.

  Although the length of the direction in which the flow path 110 of the honeycomb filter 100 extends is not particularly limited, it can be set to, for example, 30 to 500 mm. Moreover, the outer diameter of the honeycomb filter 100 is not particularly limited, but may be, for example, 30 to 500 mm. The size of the cross section of the channel 110 can be set to 0.5 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 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 channels 110” and the “remaining portion of the plurality of channels 110” described above are preferably viewed from the end face side as shown in FIG. Of the plurality of flow paths arranged in a matrix, a combination of flow paths selected every other in the vertical and horizontal directions.

  As shown in FIG. 1B, the gas supplied to the honeycomb filter 100 from the left end of the flow path 110 passes through the partition wall 112 and reaches the adjacent flow path 110, and the flow path 110 It is discharged from the right end. 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 pore-forming agent, 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.

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

  The inspection apparatus 400 includes a blower 14 that provides air, an air supply unit 56 that guides air supplied from the blower 14 to one end surface (hereinafter, also referred to as a lower end surface) 100b of the honeycomb filter 100, and gas flow detection. Unit 50 and an infrared camera 220.

  The air supply unit 56 has a pipe 54 connected to the blower 14 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 the lower end portion of the honeycomb filter 100 from the outside, and a space forming portion 52 that forms a space V in a portion facing the lower end surface 100b. Although the flow rate of the air 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 average linear velocity at the opening surface of the flow path on the inflow side can be set to 0.01 to 10 m / s.

  The gas flow detection unit 50 includes a gas receiving member 10, a frame member 20 that holds the gas receiving member 10 in a planar state, and a heater 30 that heats the gas receiving member 10.

  In the gas flow detection unit 50, the gas receiving member 10 is disposed at a position facing the other end surface (hereinafter sometimes referred to as the upper end surface) 100t of the honeycomb filter 100, and the gas discharged from the upper end surface 100t is gas receiving. The honeycomb filter 100 is held so as to hit the member 10. The distance between the gas receiving member 10 and the upper end surface 100t of the honeycomb filter 100 is not particularly limited, but is preferably 1 to 50 mm in order to increase the defect detection accuracy.

The material of the gas receiving member 10 is preferably excellent in thermal conductivity, and metals such as stainless steel and brass are preferable.
The gas receiving member 10 preferably has a plurality of holes so that gas can pass therethrough. It is preferable that the hole of the gas receiving member 10 is opposed to the opening of each flow path 110 opened to the other end face 100 t of the honeycomb filter 100 at a portion that is not a hole of the gas receiving member 10.

  Specifically, the gas receiving member 10 is preferably a metal net, a metal porous plate, or a metal porous plate. The metal net is a braided metal wire, and has a plurality of openings (eyes) of a predetermined size between the wires. The aperture ratio is, for example, 20 to 80%. For example, as shown in FIG. 3, a metal net 11 knitted with vertical wires 11a and horizontal wires 11b can be used. The mesh opening of the metal mesh can be set to 37 to 2830 μm, for example. In terms of the number of meshes, it can be 400 mesh to 7 mesh.

  When the metal net 11 is used, as shown in FIG. 3, it is preferable that the intersection points 11 c of the vertical wires 11 a and the horizontal wires 11 b are arranged to face the open flow paths 110, respectively. Note that the mesh intersection 11c need not face the sealing portion 114. Further, the intersection 11c may be opposed to a portion other than the open channel 110.

  A metal perforated plate is a plate in which a plurality of through holes that penetrate the front and back surfaces of the metal plate are formed in a square arrangement or a staggered arrangement, and the through holes are formed by a method such as punching, etching, or electroforming. Can be formed. The diameter of the through hole can be 0.1 to 2.5 mm. The aperture ratio is, for example, 20 to 80%. As shown in FIG. 4, the shape, size, and arrangement of the through holes are such that at least the portions 12 c that are not through holes are located at the portions facing the open flow path 110. preferable. In the present embodiment, the through holes 12 a having the same shape and size of the openings of the flow passage 110 are arranged at the same pitch as the pitch of the flow passage 110.

  As shown in FIG. 5, the metal porous plate is a sponge-like metal plate in which a plurality of pores 13 a communicating between the front and back sides are formed, and is also referred to as a foam metal plate. The diameter of the pores can be set to 1 to 100 μm, for example. The porosity is preferably 10 to 99%.

  Unlike FIG. 3 and FIG. 4, the diameter of the opening of the metal mesh, the diameter of the through hole of the metal porous plate, and the pitch thereof are sufficiently smaller than the diameter and pitch of the flow path of the honeycomb filter. A mode in which a plurality of openings and through holes of the gas receiving member 10 are arranged to face each of the opened flow paths 110 is also possible.

  When the cross-sectional shape of the flow path of the honeycomb filter 100 or the cross-sectional shape of the hole of the gas receiving member 10 is not a circle, the diameter can be defined by a diameter obtained by converting the cross-sectional area into a circle.

  Although the thickness of the gas receiving member 10 is not specifically limited, For example, it can be set as about 0.01-30 mm.

  The outer shape of the gas receiving member 10 is not particularly limited as long as it is a size that can cover the upper end surface of the honeycomb filter 100, and is not particularly limited to a circular shape, a rectangular shape, or the like. In this embodiment, as shown in FIGS.

  The shape and structure of the frame member 20 are not particularly limited as long as the gas receiving member 10 can be held. In particular, as shown in FIGS. 2, 3, etc., a ring shape arranged so as to sandwich the outer peripheral portion of the gas receiving member 10 is preferable. The frame member 20 is preferably made of metal so as to transfer heat from the heater to the gas receiving member 10 satisfactorily.

  The heater 30 is disposed so as to surround the outer periphery of the frame member 20. The type of the heater 30 is not particularly limited, and a heater such as a ribbon heater or a flexible heater that can easily control the heating amount and temperature by power control is preferable. The heater 30 is preferably arranged and controlled so as to maintain the gas receiving member 10 uniformly at a predetermined temperature.

  The infrared camera (temperature measurement unit) 220 is disposed to face the upper surface of the gas receiving member 10, detects the intensity of infrared rays emitted from the gas receiving member 10, and acquires a temperature distribution image of the gas receiving member 10. Such an infrared camera is also called a thermographic device. A computer 230 that performs image processing is connected to the infrared camera 220. The computer 230 analyzes an image captured by the infrared camera 220 and detects a portion having a relatively low temperature. For example, a portion having a temperature lower than a predetermined threshold value may be extracted from the image, and this portion may be set as a place having a defect. 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.

  First, the filter connecting portion 53 is attached to the lower portion of the honeycomb filter 100. Further, the heater 30 is driven to heat the gas receiving member 10. Although heating temperature is not specifically limited, It is preferable to set it as 100-500 degreeC, and it is preferable to set it as 200-400 degreeC. At this time, in the vicinity of the upper end surface 100t of the honeycomb filter 100, it is preferable that the flow of the atmospheric gas is almost absent, for example, a flow rate of 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.

  Next, the blower 14 is driven to supply room temperature air to the lower end surface 100b of the honeycomb filter 100 via the air supply unit 56 (supply process). The temperature of the supplied air is preferably 0 to 50 ° C, and more preferably 0 to 30 ° C.

  Thereby, the gas flows out from the upper end surface 100t of the honeycomb filter 100. When a hole h as shown in FIG. 2 exists between the flow paths 110, a direct flow path that connects the upper end surface 100t and the lower end surface 100b is formed by the flow path 110x, the hole h, and the flow path 110y. Therefore, as shown by the arrow G, air flows out from the upper end of the defective flow path 110 y intensively at a higher flow rate or flow velocity than the other flow paths 110. Similarly, when the sealing portion 114 is missing, or when there is a defect such as a gap between the sealing portion 114 and the flow path 110, air flows out in a concentrated manner.

  The gas flowing out from the upper end surface 100t of the honeycomb filter 100 flows through the gas receiving member 10, but the temperature of the gas flow rate and the high velocity part of the gas receiving member 10 is higher than that of the other parts. It will be strongly cooled. As a result, temperature unevenness is generated in the gas receiving member 10. This temperature unevenness can be detected by the infrared camera 220 (temperature distribution detection step).

  At this time, as shown in FIG. 6A, when there is no defect in the honeycomb filter 100, there is almost no temperature unevenness in the region A corresponding to the gas receiving member 10 in the image of the infrared camera. When the honeycomb filter 100 has holes h, as shown in FIG. 6 (b), a low temperature region B is observed in the region A corresponding to the gas receiving member 10, and thus there is no defect. The location can be specified. Determination of the presence / absence of a defect and identification of a location can be automated by the computer 230 using a known image processing method. In FIG. 6, the darker the color, the higher the temperature.

  According to the present invention, in the defective channel, the amount of gas is increased as compared with the normal channel, so that the gas receiving member 10 is cooled more strongly than the other portions, and temperature unevenness occurs in the gas receiving member. Then, by detecting the temperature distribution of the gas receiving member, it is possible to easily detect the presence / absence and location of the channel. Further, since it is not necessary to heat the honeycomb filter 100 and it is not necessary to cool the honeycomb filter 100 after the inspection, the inspection can be performed quickly.

  Further, when a metal is used as the gas receiving member 10, since the heat conductivity is high, the gas receiving member 10 can be quickly heated, and the gas receiving member 10 can be quickly cooled based on the defective portion of the honeycomb filter 100. Is called. Therefore, a quicker inspection is possible.

  Further, when a plate having a plurality of holes is used as the gas receiving member 10, the gas can be transmitted, so that the position detection accuracy of the defective part is also improved.

The present invention is not limited to the above-described embodiment, and various modifications can be made.
For example, in the above embodiment, the gas supplied to the honeycomb filter 100 is air, but the present invention can also be implemented using a gas other than air, such as nitrogen.

  In addition, the gas receiving member 10 is not a net woven of metal wires, but a wire group extending in parallel with each other in a direction parallel to each other on a wire group extending in parallel in one direction, or in one direction. The present invention can be implemented even with only a group of wires extending in parallel to each other.

  In the above embodiment, a member having a plurality of holes is used as the gas receiving member 10. However, the gas receiving member 10 may be implemented using a plate having no holes.

  Further, when the gas receiving member 10 has sufficient strength, the frame member 20 may not be used.

  Further, the heater 30 may heat the gas receiving member by directly contacting the gas receiving member 10 instead of through the frame member 20. Further, for example, it is possible to use a heater that energizes and heats the wire of the net itself.

  In the above embodiment, the temperature distribution of the gas receiving member is measured in a non-contact manner by an infrared camera. However, for example, a temperature sensor such as a thermocouple is arranged on the gas receiving member to measure the temperature distribution. Is possible.

  In the above embodiment, the gas receiving member 10 is heated to a predetermined temperature and then the gas from the honeycomb filter 100 is applied to the gas receiving member 10. However, the present invention is not limited to this. The heating of the gas receiving member 10 can be performed for the first time in a state where it is applied to the gas receiving member 10, and can be performed even if these are started simultaneously.

  Further, 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 with a non-porous green body that has not been fired and has been sealed. In this case, there is no outflow of gas from the channel without defects.

  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.

  DESCRIPTION OF SYMBOLS 10 ... Gas receiving member, 11 ... Metal net | network, 12 ... Metal porous board, 13 ... Metal porous board, 30 ... Heater, 53 ... Supply part, 100 ... Honeycomb filter, 100t ... The other end surface of a honeycomb filter, 100b ... Honeycomb filter , One end face, 110, a flow path, 112, a partition, 114, a sealing part, 220, an infrared camera (temperature measurement part), 400, an inspection device.

Claims (6)

A step of supplying gas to the one end face of the honeycomb filter having a partition wall that forms a plurality of flow paths from one end face to the other end face, and a sealing portion that closes one end of each of the flow paths;
Supplying the gas discharged from the other end surface of the honeycomb filter to the gas receiving member, which is disposed so as to face the other end surface and heated;
And a step of measuring a temperature distribution of the gas receiving member.   The method according to claim 1, wherein the temperature distribution of the gas receiving member is measured by an infrared camera.   The method of claim 1, wherein the gas receiving member has a plurality of holes.   The method according to claim 1, wherein the gas receiving member is a metal net, a metal porous plate, or a metal porous plate.   The method according to any one of claims 1 to 3, wherein the gas supplied to one end face of the honeycomb filter is a gas of 50 ° C or lower. A partition that forms a plurality of flow paths from one end face to the other end face, and a supply section that supplies gas to one end face of the honeycomb filter having a sealing portion that closes one end of each flow path,
A gas receiving member disposed to face the other end surface of the honeycomb filter;
A heater for heating the gas receiving member;
A honeycomb filter defect inspection apparatus comprising: a temperature measurement unit that measures a temperature distribution of the gas receiving member.