JP3065746B2 - Honeycomb filter sealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing an end opening of a predetermined through hole among a plurality of through holes provided in a porous honeycomb filter.

[0002]

2. Description of the Related Art Conventionally, as a method of sealing an end opening of a through-hole provided in a honeycomb filter, Japanese Patent Application Laid-Open Publication No.
A method disclosed in JP-A-7-7215 is known.
In this method, a sealing film made of paper or resin is attached to the end face of the filter. A plurality of holes are formed in the film to seal the end openings in a checkered pattern, and the sealant is pressure-introduced into the end openings through each hole. Thereby, only a predetermined end opening is sealed.

[0003]

However, when a sealing film is used, when the sealing agent is introduced under pressure, the film may be damaged, or the adhesion of the film may be deteriorated and the sticking position may be shifted. May be. In this case, the sealing agent may not sufficiently flow into the opening at the end to be sealed, and the sealing may be incomplete. In addition, from the gap formed between the film and the filter, there is a possibility that the sealing agent may flow into an end opening that does not require sealing by mistake, in which case, in removing the sealing agent, It was uneconomical to spend a lot of time and effort.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to ensure that a predetermined end opening of a through hole formed in a honeycomb filter can be reliably sealed, and that a sealing unnecessary portion can be formed. An object of the present invention is to provide a method for sealing a honeycomb filter which can easily and completely remove a sealant.

[0005]

According to the present invention, there is provided a method for sealing an end opening of a predetermined through hole among a plurality of through holes provided in a porous honeycomb filter. In the above, at both ends of the through hole, a sealant is supplied to at least all of the one end openings, and after closing them, a plurality of holes corresponding to the unsealed end openings are provided in advance. The mask is brought into intimate contact with one end face of the honeycomb filter, and the sealing agent in the unsealed end opening is caused to collide with sand blast through the hole of the mask to remove the sealing agent, thereby covering the mask with the mask. Only the closed end opening was kept in a sealed state.

[0006]

According to this method of closing all the end openings in advance, since the sealant is supplied non-selectively to each end opening, the supply of the sealant can be performed reliably. Along with
Each end opening can be uniformly and reliably closed. When the mask is arranged on the sealing-side end face of the filter, only the sealant of the end opening to be kept in the sealed state is protected by the mask, and it is not necessary to maintain the sealed state. Only the sealant is exposed to the outside through the holes in the mask. When sandblasting is performed in this state, the sandblast collides only with the sealing agent exposed to the outside, and the sealing agent is easily and completely removed by fine abrasive grains.

The sealing agent used in the sealing method is a viscous fluid containing silicon carbide as a main component, and is preferably sintered after being supplied to the end opening of the through hole. The reason is that without viscosity, it is not retained in the end opening. The reason for sintering after supplying the sealing agent is to complete the sealing and integrate the honeycomb filter with the honeycomb filter.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a honeycomb filter is manufactured by applying the sealing method of the present invention will be described below in detail with reference to FIGS.

FIG. 1 shows a porous honeycomb filter F to be subjected to the sealing method of the present invention. Generally, materials such as porous silicon carbide, cordierite, and mullite are used for the honeycomb filter F. A large number of through holes F _H are formed in the filter F along the longitudinal direction, and the through holes F _H open at both end surfaces of the filter F,
It has a rectangular cross section, a circular cross section, a hexagonal cross section, and the like. As these conditions are met in the present embodiment, is made of porous silicon carbide and length 15cm, the honeycomb molded body F (pitch of the through holes F _H is 2 mm, cross-sectional square shape) of the outer diameter of 15cm extrusion molding Manufactured by. Further, the molded body F is fired after drying and degreasing, sealing of the open end O ₁ is carried out thereafter by the sealing paste P.

The paste P has an average particle diameter of 0.3.
An average particle diameter of 1 part per 70 parts by weight of β-type silicon carbide powder of μm
A mixture of 30 parts by weight of α-type silicon carbide powder of 00 μm, 25 parts by weight of a binder composed of 6 parts by weight of methylcellulose and 19 parts by weight of α-terpineol was used as a raw material.
After kneading these compounds, the viscosity becomes 500,000 mpa.
Was adjusted to

Then, about 50 mm of the paste P was filled in a dipping container, and one end face of the compact F was immersed in the paste P for one minute. By this processing, the paste P having high viscosity is caused to penetrate into each end opening O ₁ , O ₂ of the molded body F, and as shown in FIG. 2, all the end openings O ₁ , O ₂ on one end face are securely formed. Closed. And the end opening O
₁ , The paste P filled in O ₂ was dried for 60 minutes. Thereafter, the paste P was temporarily calcined at 1700 ° C. for 4 hours in an inert atmosphere to fix the paste P in the end openings O ₁ and O ₂ . Next, the molded body F was subjected to sand blast.

FIG. 3 shows a disk-shaped mask M used for sandblasting. The mask M
Are formed with a plurality of holes _MH communicating with each other in the vertical direction. Each hole M _H are formed corresponding to the arrangement interval and the cross-sectional shape of the end opening O ₂ without sealing, the hole M _H in the mask M in the present embodiment the length D of the cross-section quadrilateral a and one side
Is set to 2 mm. The material of the mask M needs to be able to withstand sandblasting. As such a material, for example, a metal, a ceramic, a polymer material, or the like is suitable. In this embodiment, a metal is used.

[0013] The mask M in a state of being aligned and forming position of the end opening O ₁ of the compact F side and the formation position of the holes M _H, are closely arranged on the end face of the molded body F. Therefore, only the end opening O ₁ to be kept sealed is covered by the mask M, and the end opening O _{2 that} does not need to be kept sealed.
Is exposed to the outside through each hole _MH .

In the sand blast treatment, α-type silicon carbide (made by Fujimi Abrasive Co., Ltd., GC # 200) was used. Then, while setting the conditions for the sandblaster, the molded body F
The sandblasting treatment was performed by disposing the mask M mounting side of the above in opposition to the abrasive grain projection port (see FIG. 3). Through this process, portions exposed to the outside, i.e. the paste P in the end opening O ₂ without sealing is completely removed by the fine abrasive particles. Then, after sealing and sandblasting the other end face of the molded body F by the above-described method, main firing is performed at 2200 ° C. for 4 hours under an inert atmosphere, and both end faces are in a checkered pattern as shown in FIG. A desired sealed honeycomb filter F was manufactured.

[0015] In the filter F was prepared by a sealing method described above, the end portion in the opening O ₁ are uniformly filled paste P, gaps and peeling the sealing portion was observed.
Further, the paste P in the end opening O ₂ which does not require sealing is used.
Had been completely removed.

As a comparative example with respect to this embodiment, a sealing film in which a plurality of paste passage holes were previously formed was adhered, and the paste P was filled under pressure by a press-fitting method.
Further, in this method, the sealing paste P having the same composition as that of the embodiment was used, and the honeycomb molded body having the same standard was used. As a result, it was observed that a part of the film was damaged, and that the paste P had penetrated into the end openings other than the end openings to be sealed. Further, due to the non-uniformity of the holes formed in the film, the filling amount of the paste P slightly varied, and gaps and peeling were observed in some of the sealing portions.

The present invention is not limited to the above embodiment, but can be modified without departing from the spirit of the invention. For example, instead of supplying the paste P to the open end portions O ₁ and O ₂ by the dipping method as in the embodiment, it is of course possible to introduce the paste P by press-fitting.

[0018]

As described above in detail, according to the method for sealing a honeycomb filter of the present invention, the end opening of a predetermined through hole formed in the honeycomb filter can be reliably sealed, and sealing is not required. This provides an excellent effect that the sealant in the portion can be easily and completely removed.

[Brief description of the drawings]

FIG. 1 is a partial side sectional view showing a honeycomb filter before paste supply.

FIG. 2 is a partial sectional side view of a honeycomb filter in a state where all end openings on one end face are sealed.

FIG. 3 is a partial side sectional view showing a honeycomb filter and a mask at the time of sandblasting.

FIG. 4 is a partial side sectional view showing the honeycomb filter after sealing is completed.

[Explanation of symbols]

F (honeycomb) filter, F _H through-hole, O ₁ (to be sealed) end opening, O ₂ (not sealed) end opening,
M mask, M _H hole (s), P Paste as sealant.

Claims (2)

(57) [Claims] 1. A filter provided on a porous honeycomb filter (F).
Through holes (F_H) Out of the predetermined through hole
(F_H) End opening (O₁), Wherein the through hole (F_H) At both ends (O₁, O_Two)
In addition, at least one end opening (O₁, O_TwoSealed for all)
Do not seal after supplying agent (P) and closing them
End opening (O_Two) Corresponding to a plurality of holes (M_H) Is set in advance.
The mask (M) that has been shaken is removed from the honeycomb filter (F).
The end opening (O _TwoSealing inside
Sand blasting the agent (P) with the holes (M) in the mask (M)
_H) To remove the sealant (P)
As a result, the end covered by the mask (M) is opened.
Mouth (O₁) Is kept in a sealed state.
A method for sealing a honeycomb filter. 2. The sealant (P) contains silicon carbide as a main component.
Viscous fluid having a through hole (F _H) End opening (O
₁3. The honeycomb according to claim 1, wherein the honeycomb is sintered after being supplied.
Cam filter sealing method.