JPH07136435A - Filter for exhaust gas purifying apparatus and production thereof - Google Patents

Abstract

PURPOSE:To enhance the production efficiency, in a filter of an exhaust gas purifying device in a diesel engine, by spirally providing the passages demarcated so as to be surrounded by a porous flat plate and a porous corrugated plate and alternately sealing the start and terminal end parts of the passages. CONSTITUTION:A heat resistant metal net 1 is passed through a slurry 2 composed of a mixture of a heat-resistant metal powder and an org. binder and further passed through a slit 4 to adjust the thickness of the slurry 2 to definite quantity and, subsequently, the impregnated metal net is dried by a fan 3 to obtain a plate-shaped green member 5. A part of the plate-shaped green members is passed through a pair of corrugated plate rolling rolls to form a corrugated plate-shaped green member. Both green members are superposed one upon another to constitute a composite green member having passages 9 and, thereafter, the composite green member is wound and the start and terminal end parts of the passages 9 surrounded by both green members are alternately sealed with a plastic substance 10 to complete a cylindrical filter 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for an exhaust gas purifying apparatus for collecting soot and the like contained in exhaust gas from diesel engines and a method for manufacturing the same.

[0002]

2. Description of the Related Art Diesel engine exhaust gas contains a large amount of soot due to incomplete combustion. Some diesel vehicles, such as tunnel work trucks and large city buses, remove soot from the exhaust gas. The exhaust gas purifying device is installed.

The exhaust gas purifying apparatus has a filter built therein. When soot is deposited on the filter, the deposited soot is burned to regenerate the filter.

A ceramic filter is usually used as the above filter, but when the soot accumulated on the filter is burned and regenerated, it is rapidly heated and may be damaged by thermal shock. Therefore, in recent years, a porous heat-resistant metal filter that is hardly damaged by thermal shock has been developed (see Japanese Patent Laid-Open No. 3-178303).

[0005]

In the conventional filter for exhaust gas purifying apparatus described above, a plurality of filter plates produced by sintering in advance are laminated, and the end portions of the filter plates are alternately joined via a stirrup. Since it is manufactured by various processes such as sintering process and plastic working process, the production efficiency is poor and the price is high, so replacement is costly even when the filter reaches the end of its life. The current situation is to operate or run without doing.

[0006]

Therefore, the present inventors have
As a result of conducting research to manufacture a filter for an exhaust gas purifying apparatus at a lower cost than before, two flat green bodies made of a mixture of heat-resistant metal powder and an organic binder were produced. Of the above two flat green bodies, One piece is corrugated to produce a corrugated green body, the flat green body and the corrugated green body are superposed to produce a composite green body, and the composite green body is wound to form a corrugated sheet. A wound green body having a passage composed of a flat portion and a flat portion is manufactured, and the passage end portion of the wound green body is made of one or more of heat-resistant metal powder, ceramic powder, and heat-resistant glass powder and an organic binder. Alternately plugged with a paste-like plastic composition consisting of a mixture of the above and the sintered wound green body, and sintering the plugged portion, the exhaust gas purifying apparatus is entirely porous except for the plugged portion. F Luther is the finding that can be produced only by the sintering process were obtained. This invention was made on the basis of the results of such research.
A filter for an exhaust gas purifying apparatus, in which passages surrounded by a porous flat plate and a porous corrugated plate are arranged in a spiral shape, and the start end and the end are alternately plugged, (2) Heat-resistant metal powder And a step of producing a flat green body composed of a mixture of an organic binder, a step of corrugating the flat green body to produce a corrugated green body, the flat green body and the corrugated green body are stacked. A step of producing a composite green body having a passage together, a step of producing a wound green body having a passage by winding the composite green body, a passage end portion of the winding green body, a heat-resistant metal powder,
Alternately plugging with a paste-like plastic composition (hereinafter referred to as the paste-like plastic composition) consisting of a mixture of one or more of ceramic powder and heat-resistant glass powder and an organic binder, and this plugging The method for producing a filter for an exhaust gas purifying apparatus comprises the steps of: sintering the stopped wound green body; and a step of sintering the wound green body.

Further, according to the method of manufacturing a filter for an exhaust gas purifying apparatus of the present invention, the wound green body is manufactured by winding the composite green body and simultaneously plugging the passage ends alternately. It is also characterized in that a filter for an exhaust gas purifying apparatus is manufactured by sintering a green body.

The exhaust gas purifying apparatus filter and the method for producing the same according to the present invention will be described more specifically with reference to the drawings.

FIG. 1 is an explanatory view for producing a flat plate-shaped green body composed of a heat-resistant metal powder and an organic binder. In order to produce a long flat plate-shaped green body which can be particularly put to practical use, FIG. 1, the refractory metal wire mesh 1 is passed through a slurry 2 composed of a mixture of heat resistant metal powder and an organic binder, and then the slurry 2 is passed through a slit 4 to a predetermined thickness on the surface of the heat resistant metal wire mesh 1. It is applied as described above and dried by a fan 3 or the like to produce a flat green body 5, which is wound and stored.

On the other hand, a part of the flat green body 5 is shown in FIG.
As shown in (3), the corrugated plate-shaped green body 6 is produced by passing between the corrugated plate rolling rolls 7 and 7 '.

The plate-shaped green body 5 and the corrugated plate-shaped green body 6 thus produced are overlapped with each other as shown in FIG. 3, and if necessary bonded, a composite green body 8 having a passage 9 is obtained. can get.

The composite green body 8 is wound, and the starting end portion and the end portion of the passage 9 surrounded by the flat plate-like green body 5 and the corrugated plate-like green body 6 are alternately filled with the paste-like plastic material 10 and plugged. After stopping and then sintering, a cylindrical filter 11 as shown in the perspective view of FIG. 4 is obtained.

As shown in FIG. 3, the paste-like plastic material 10 is piled up along the opposite ends of the front and back surfaces of the flat green body 5, and the corrugated plate-like green body 6 is laid on it to form a composite green. When the body 8 is produced and the composite green body 8 is wound in the same manner, a wound green body in which the start end and the end of the passage 9 are alternately plugged is obtained, and the wound green body is sintered. By doing so, the cylindrical filter 11 shown in FIG. 4 can be manufactured. The winding green body can be sintered by exactly the same method as a method for producing a porous sintered body by a normal doctor blade method.

In the cylindrical filter thus produced, as shown in FIG. 4, the passages 9 surrounded by the porous flat plate 17 and the porous corrugated plate 18 are spirally arranged. The start end and the end of 9 are plugged 19 alternately.

FIG. 5 is a sectional view showing the state where the cylindrical filter 11 is attached to the exhaust gas purifying apparatus. In FIG. 5, 12 is a package, 13 is a filter resistance measuring device, and 14
Is a heater, 15 is a battery, and 16 is a CPU.

The heater 14 is inserted into the center of the cylindrical filter 11 housed in the package 12, and the heater 1
4 is electrically connected to the battery 15. On the other hand, it is electrically connected to the filter resistance measuring device 13 so that the resistance of the cylindrical filter 11 can be measured. Furthermore, the filter resistance measuring device 13 and the battery 15
Are electrically connected to the CPU 16.

When exhaust gas is passed through the exhaust gas purifying apparatus having such a structure, the resistance value measured by the filter resistance measuring device decreases as the soot is collected and deposited on the cylindrical filter 11, and a predetermined resistance value is detected. At the same time, the CPU 16 commands the battery 15 to be energized and applies a current to the heater 14 to heat it, and at the same time, a current is also applied to the cylindrical filter 11 itself to generate Joule heat, and the cylindrical filter 11 is heated and collected. It can burn soot and regenerate the filter function.

When the composite green body 8 shown in FIG. 3 is spirally wound, one end is spirally dented into a mortar-like shape, and the other end is spirally raised to a cylindrical shape. A wound green body is obtained, and a spiral cylindrical filter is obtained by sintering the spiral wound green body.

FIG. 6 is a sectional view showing a state in which the spiral cylindrical filter is built in the exhaust gas purifying apparatus.

As shown in the sectional view of FIG. 6, an exhaust gas purifying apparatus is manufactured by mounting a spiral cylindrical filter 11 'in the package 12 with one end of the mortar shape facing the exhaust gas inflow direction. When soot is collected using the soot, the soot flows toward the bottom of the mortar, so that a large amount of soot is collected at the center of the spiral cylindrical filter 11 '.

However, since the heater 14 is provided in the central portion as shown in FIG. 6, the current density flowing through the spiral cylindrical filter 11 'is larger in the central portion than in the outer peripheral portion. , Spiral cylindrical filter 11 '
The central part of the is heated to a higher temperature than the outer part and is more likely to burn. Therefore, even if a large amount of soot is collected in the central portion of the spiral cylindrical filter 11 ', the soot is efficiently burned and the filter can be efficiently regenerated. 6 is the same as FIG. 5 except that the spiral cylindrical filter has a reference numeral 11 ′, and therefore the description of the reference numerals in FIG. 6 is omitted.

5 and 6, a heater is attached to the central portion of the cylindrical filter 11 and the spiral cylindrical filter 11 'as a means for burning the collected soot, but the present invention is not limited to this. Alternatively, a conventional linear heater or gas burner may be installed in front of the cylindrical filter.

Further, although the heat-resistant metal wire net was used in the production of the flat plate-shaped green body, the flat plate-shaped green body can also be produced by the ordinary doctor blade method without using the wire mesh.

[0024]

[Examples] Metal powder: SUS310S powder (average particle size 20 μm) ... 1,000 g Binder: Polyvinyl butyral resin ... 50 g Plasticizer: Di-n-butyl phthalate ...・ ・ ・ 25 g Solvent: Ethanol / toluene mixed solution ・ ・ ・ ・ ・ ・ 400 g was kneaded and defoamed to prepare a metal powder slurry.

Further, a wire mesh made of SUS310S having a width of 20 cm and a length of 10 m of 60 mesh was prepared.

The metal mesh was passed through the metal powder slurry, the metal powder slurry was applied to the metal mesh, and the metal mesh was dried by passing through a slit to prepare a flat green body having a thickness of 0.4 mm. On the other hand, metal powder: SUS310S powder (average particle size 20 μm) ... 1,000 g Binder: Water-soluble methyl cellulose ... 10 g Plasticizer: Di-n-butyl phthalate ... ........ 23 g Solvent: water ........................ 300 g was kneaded and defoamed to prepare a paste-like plastic composition.

Amplitude: 3 mm on a part of the flat green body
The corrugated plate was processed to prepare a corrugated green body.

A corrugated plate-shaped green body was superposed on and bonded to the flat plate-shaped green body to prepare a composite green body.

Among the wound green bodies produced by winding this composite green body, one end and the other end of the passage of the wound green body are alternately filled with the above-mentioned paste-like plastic composition to seal the plugs. Then, when the plugged wound green body was sintered in a hydrogen atmosphere at a temperature of 1200 ° C. for 1 hour, a passage formed by a porous flat plate and a porous corrugated plate was formed. A cylindrical filter was obtained, which was arranged in a spiral shape and in which the beginning and the end of the passage were alternately plugged.

When the above-mentioned cylindrical filter was built in an exhaust gas purifying apparatus and the exhaust gas purifying apparatus was attached to an exhaust pipe of a 2000cc direct injection type diesel engine and tested, a soot trapping efficiency superior to the conventional one was obtained.

[0031]

As described above, according to the present invention, since the filter can be manufactured only by the sintering process, the filter can be manufactured at a lower cost than the conventional one, and the soot of the filter incorporated in the exhaust gas purifying apparatus can be manufactured. Because of its excellent collection efficiency, it can greatly contribute to the improvement of the environment.

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining a method of manufacturing a flat green body.

FIG. 2 is a cross-sectional view for explaining a method of manufacturing a corrugated plate-shaped green body.

FIG. 3 is a perspective view for explaining a method of manufacturing a composite green body.

FIG. 4 is a perspective view of the cylindrical filter of the present invention.

FIG. 5 is a sectional view of an exhaust gas purifying apparatus to which the cylindrical filter of the present invention is attached.

FIG. 6 is a cross-sectional view of an exhaust gas purifying apparatus equipped with the cylindrical filter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat-resistant metal wire mesh 2 Slurry 3 Fan 4 Slit 5 Flat green body 6 Corrugated green body 7 Corrugated sheet rolling roll 7'Corrugated sheet rolling roll 8 Composite green body 9 Passage 10 Paste-like plastic material 11 Cylindrical filter 11 'Spiral Cylindrical filter 12 Package 13 Filter resistance measuring device 14 Heater 15 Battery 16 CPU 17 Porous flat plate 18 Porous corrugated plate 19 Plugging

Claims (3)

[Claims] 1. An exhaust gas, characterized in that a passage surrounded by a porous flat plate and a porous corrugated plate is arranged in a spiral shape, and a start end portion and an end portion of this passage are alternately plugged. Filter for purification device. 2. A flat green body made of a mixture of a heat-resistant metal powder and an organic binder is produced, and the flat green body is corrugated to produce a corrugated green body. A composite green body having a passage is manufactured by superposing green green bodies, and the composite green body is wound to produce a wound green body having a passage. , A ceramic powder, a heat-resistant glass powder, or a mixture of an organic binder and one or more of them, and the mixture is alternately plugged with a paste-like plastic composition (hereinafter referred to as the paste-like plastic composition). A method for producing a filter for an exhaust gas purifying apparatus, comprising: sintering a wound green body having alternately plugged ends. 3. After manufacturing the flat plate-shaped green body and the corrugated plate-shaped green body, the paste-like plastic composition is piled up along the opposite ends of the front and back surfaces of the flat plate-shaped green body, and the corrugated plate-shaped green body is waved thereon. A composite green body with plugged end portions of the passage is manufactured by stacking plate-shaped green bodies, and the composite green body with plugged end portions of the passage is wound,
Manufacture a wound green body in which the passage ends are plugged alternately.
Next, the method for producing a filter for an exhaust gas purifying apparatus according to claim 2, wherein the wound green body in which the passage ends are alternately plugged is sintered.