JP2002537100A - Improved method of manufacturing multicellular filters - Google Patents

Abstract

  (57) [Summary] A method of plugging a honeycomb cell (12) includes providing a honeycomb having an inlet end and an outlet end, and having a number of cells (12) extending from the inlet end to the outlet end, wherein a preselected honeycomb cell opening is provided. Each step of guiding the sealing material (16) by capillary action to form a plug at the preselected cell opening. The seal may also be a thermoplastic polymer preform having an area corresponding to the cell openings on a particular surface of the honeycomb. The preform is placed on the surface of the honeycomb having the preselected cell openings, and the preform is inserted into the preselected cell openings. The preselected cell opening is heated and the preform transforms into a thermoplastic sealant, which has a plug that joins to the inner wall of the preselected cell opening and is securely positioned within the selected cell opening. A plugged honeycomb is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to an improved plugging method for manufacturing a multicellular (multicellular) filter.

[0002] The such multicellular structure background honeycomb invention find use as filters for fluids. By plugging the cells or channels of the honeycomb, the flow of fluid is forced through the cell walls, which can perform the filtering action of the particles. The flow pattern through this wall takes advantage of the high surface area / volume ratio of the honeycomb. These honeycomb filters, particularly ceramic honeycombs, have been used extensively for gas phase filtration, such as filtration of diesel particles, due to their high temperature capabilities.

Conventional plugging methods, for example, using a removable mask, pushing the plug into the unmasked cell and then removing the mask, or plugging the plug directly into the cell to be plugged The method of infusion is a very slow process. Some other disadvantages of these methods are that the cell dense structure (> 200 cells / 6.45 cm ² (i
n ² )) is difficult to apply for plugging.

[0004] Honeycomb has not yet found wide applications such as liquid filters. Since many liquid filtrations do not need to be plugged with hot materials, different solutions are needed for the methods and possibilities of plugging honeycombs for such applications. A new solution to the problem of plugging honeycombs in liquid filtration must be applicable without considering whether the honeycomb is ceramic, carbon, polymer, or some combination thereof. All filtrations show that the plug in the honeycomb exhibits a bypass (leakage of fluid around the plug) to maintain the filter's particulate, contaminant, and parasite removal properties. must not.

The present invention describes various plugging methods for plugging honeycombs used for fluid filtration. This method satisfies the requirement to completely plug the groove of a particular cell to a controlled depth to prevent leakage around the plug.

[0006] In accordance with one aspect of the Summary of the Invention invention, a method for plugging the honeycomb cell, which has an inlet end and an outlet end, providing a honeycomb having a plurality of cells extending from the inlet end to the outlet end Guiding the sealing material by capillary action to the preselected honeycomb cell openings,
Forming the plug at the preselected cell opening as described above.

According to another aspect of the invention, the seal may be a thermoplastic polymer preform having an area corresponding to a cell opening on a particular surface of the honeycomb, corresponding to the opening to be plugged. That region has a thermoplastic sealant. The sealing material has dimensions that can be fixedly fitted into the cell opening of the honeycomb to be plugged. The preform is located on the honeycomb surface having the preselected cell openings such that the sealant is inserted into the preselected cell openings. The preselected cell opening is plugged with a plug that is heated to deform the thermoplastic sealant and adheres to the inner wall of the preselected cell opening and is securely positioned within the selected cell opening. Honeycombs are manufactured.

[0008] DETAILED DESCRIPTION OF THE INVENTION The present invention, then capped honeycomb for filtration of fluids, a method for producing a filter having a wall flow. In particular, the present invention relates to various methods of applying a sealant to a controlled depth and through pores in a honeycomb cell to form a plug. The sealing material forms a plug integral with the cell walls and the pores in the walls.

[0009] The honeycomb can be made from any material, such as ceramic, metal, polymer, carbon or activated carbon, glass, glass ceramic, or a combination thereof.

[0010] The honeycomb can have any cell density, but the cell density is typically 23
5 cells / cm ² (about 1500 cells / in ² ) to 1.5 cells / cm ² (about 10 cells / cm ² )
Cells / in ² ). They have variable wall thickness, but the wall thickness typically ranges from about 0.1 to about 1.5 mm (about 4 to about 60 mils). The present invention is particularly useful for honeycombs having a high density of 31 cells / cm ² (200 cells / in ² ) or more.

The sealing material is selected according to the material of the honeycomb. A strong chemical, mechanical or frictional bond must be made with the honeycomb cell surface so that there is no leakage around the formed plug. It is to be understood that some examples of typical sealants or plugs are not limited to the invention, but are polymeric materials such as epoxies, silicones, waxes, thermoplastic polymers, and the like. Inorganic / organic blends such as ceramic / polymer blends, and the like.

There are several ways in which a plug can be plugged.

In one embodiment, the preselected cell is a liquid-based sealing material that is plugged by capillary action. The top of the cell opening to be plugged is in contact with the seal and the seal is capillarized (as opposed to pushing the seal into the cell by injection, pressurization, or some other conventional method). Forces can be drawn into the cell to a predetermined depth. The present invention does not require that the seal be placed exactly at the center of the cell to be plugged. As long as most of the end of the seal is at the top of the required cell, misalignment is not a problem as the seal is drawn into the cell by capillary action. The sealant can be applied to individual cells, or can be applied in a continuous, diagonal, linear pattern. The latter approach is more efficient because it facilitates the sealing of a large number of cells.
The degree to which the sealing material enters the cell is determined by the size of the cell, the viscosity of the sealing material, and the wettability of the sealing material with the cell. Depending on the cell size, the properties of the sealing material
It can be adjusted so as to penetrate into the pores up to a predetermined plugging depth. For example, the depth at which the plug enters can be adjusted by the viscosity of the sealing material. The greater the viscosity of the sealing material, the shorter the depth of the plug. Low viscosity sealing materials
In addition, a plug having a short depth can be produced by using it together with an ultraviolet (UV) curing initiator in a sealing material and exposing the portion to ultraviolet irradiation.

In another embodiment, a seal is applied to the entire end of the honeycomb. As the sealing material is drawn into the cells, each cell is filled to a predetermined depth (as opposed to completely filling the entire groove of the cell). The sealed honeycomb end then:
After being removed from the sealing material, a rod having a diameter smaller than the cell size and arranged in a predetermined open cell pattern is inserted into the honeycomb. High viscosity seals adhere to these rods and are removed from the cells as the rods are pulled up from the honeycomb. This process is repeated to create an opposite pattern on the other side of the honeycomb.

In another embodiment, cells that are left open are masked with a removable, or temporary, masking material. The entire surface of the honeycomb is exposed to the sealing material, and the sealing material fills the unmasked cells by capillary action. In this approach, particularly suitable as masking materials, it should be understood that the present invention is not limited to such, but silicones that are removed during processing, waxes that melt at low temperatures, and thermoplastic elastomers. The melting point of the wax used as the temporary masking material must be low enough so that the epoxy or other plug can remove low melting compounds without damage. Particularly suitable as a sealing material is a two-part epoxy. The density of each cell requires a different viscosity, with higher cell densities requiring lower viscosities. The temporary masking material is removed by heating.

In yet another embodiment, the honeycomb cells to be plugged are plugged at once with a preformed mask. Mask plugs, which ultimately become honeycomb plugs, are made of the aforementioned plugging materials, for example, molded thermoplastic elastomers, waxes, epoxies having only an epoxy jacket that has been cured by UV or heat. The mask is physically pressed into the honeycomb and all desired cells are plugged at once. In the case of a thermoplastic elastomer or wax, the insertion into the honeycomb is hot enough to at least partially melt the plug of the mask seal, resulting in a tight, leak-tight mechanical connection. In the case of a plug with an epoxy sealant, the mechanical operation of pressing breaks the hardened jacket of the plug and allows some uncured epoxy to flow out and form a chemical bond.

In order to more fully describe the present invention, the following non-limiting examples are set forth in conjunction with the accompanying drawings.

Example 1 Use of Capillary Action on a Plugged Cell Example 1 FIGS. 1 and 1a show a honeycomb cell in contact with a sealing material and the sealing material being drawn into the cell by the force of capillary action . FIG. 1 is a schematic view showing the length of the honeycomb cell (12). The cell wall is shown as (14). Sealing material (16
) Is located at the opening of the cell. FIG. 1a is similar to FIG. 1, but shows the seal (16a) exposed to the force of the capillary action pulling the seal into the cell. FIG.
In addition to being applied to a large number of individual cells, as shown in Figure 5, it can be applied in a diagonal pattern to facilitate the process. FIG. 2 is a schematic view of a cross section of a honeycomb cell (20) having a sealing material (22) applied as a continuous line obliquely across the cross section of the honeycomb cell. FIG. 2a shows the plug (22a) of the seal in the cell (20), similar to FIG. 2, but after the seal has been able to plug the cell by capillary action. A particularly suitable seal for the foregoing embodiments is, for example, a two-part epoxy having a viscosity of about 250,000 centipoise.

Example 2 Approximately 0.71 mm (0.028) with fine pores (<10 micrometers)
A 200-cell / 6.45 cm ² (in ² ) porous ceramic honeycomb with an inch thick wall was plugged diagonally with a two-part epoxy having a viscosity of about 200,000 centipoise. . The epoxy beads were continuously fed in a diagonal linear pattern using a hand guided air injector. Opposing diagonal linear patterns were placed on both sides of the honeycomb, and the plugged portions were exposed to about 70 ° C. for about 1 hour. The final, hardened stopper depth was about 2 mm.

EXAMPLE 3 300 cells / 6.45 cm ² (in ² ) porosity with about 0.38 mm (0.015 inch) thick walls with fine pores (<2 micrometers) The ceramic honeycomb was plugged in a diagonal pattern using a two-part epoxy having a viscosity of about 100,000 centipoise. The epoxy beads were continuously fed in a diagonal linear pattern using a hand guided air injector. Opposing diagonal linear patterns were placed on both sides of the honeycomb, and the plugged portions were exposed to about 70 ° C. for about 1 hour. Final cured plug depth is about 2m
m.

Example 4 400 cells / 6.45 cm ² (in ² ) porosity with about 0.25 mm (0.010 inch) thick walls with fine pores (<3 micrometers) The ceramic honeycomb was plugged in a diagonal pattern using a two-part epoxy having a viscosity of less than about 40,000 centipoise. The epoxy bead was continuously fed in a diagonal linear pattern using an air injector guided by a computer controlled xyz table. Opposing diagonal linear patterns were placed on both sides of the honeycomb, and the plugged portions were exposed to about 70 ° C. for about 1 hour. The final, hardened stopper depth was less than 3 mm.

Example 5 Use of Capillary Action in Combination with Cell Masking FIGS. 3, 3a, 3b and 3c illustrate the use of a temporary or removable masking material for cells that are ultimately opened. The principle of masking and then exposing the entire surface of the honeycomb to the sealing material and filling the unmasked cells by capillary action is shown. FIG. 3 shows the length of the cell (32) with the mask (33) and the cell wall (34).
FIG. FIG. 3a shows a cell (32a) with a mask (33) and a cell (32a) immersed in a container (36) with a sealing material (38). FIG. 3b shows the resulting honeycomb cell (32) with mask (33) and plug of sealing material (38a).
A cell (32a) having The mask is then removed, such as by heating.
FIG. 3c is a schematic view of a honeycomb cell having a sealing material after the masking material has been removed. For example, two-part epoxies having a viscosity of about 150,000 centipoise have been used as sealants, but one suitable material for masking open cells is wax. Viscosity depends on cell geometry.

Example 6 Use of Preformed Mask with Mechanical Accessories All cells of the honeycomb to be plugged can be plugged at once using the preformed mask. The preformed mask can be made of a molded thermoplastic elastomer, or wax, or related material, and can be physically pressed into the honeycomb, as shown in FIG. A stopper is made. FIG. 4 is a schematic diagram showing the length of the honeycomb cell (42) and the cell wall (44), and a mask (46) having plugs (48) inserted into the honeycomb cell on both sides. The plugs are shown to plug the cells alternately. The application of heat to either the honeycomb or mask and the use of a wedge-shaped plug results in a mechanical seal integral with the porous honeycomb wall. FIG. 5 is a schematic view of a wedge-shaped plug (52) about to be inserted into a honeycomb cell (54) with a porous wall (56) having pores indicated by (58). FIG. 5a shows the cell after it has been plugged with a plug (52a) integrally sealed to the cell wall.

Example 7: Use of a Preformed Mask with Chemical Accessories All cells to be plugged use a preformed mask made from an epoxy having both UV and heat curable components. Can be plugged at once using.
Thin envelopes are generated using UV irradiation, allowing the material to maintain its shape. The preform is physically pressed into the honeycomb as described in Example 6. The mechanical action of pressing breaks the sheath of the wedge-shaped plug, allowing some uncured epoxy to flow into and along the cell walls. The entire preformed mask is then heat cured to allow for the creation of a chemical bond between the epoxy and the cell walls.

Example 8: Use of a plug to be fitted and then removed 100 cells / 6.45 cm with a wall of about 0.71 mm (0.028 inch) thickness with fine pores (5 μm) ^{The 2} (in ² ) porous ceramic honeycomb is immersed (1/4 inch) in a two-part epoxy having a viscosity of less than about 100,000 centipoise for less than 1 minute. The honeycomb is removed from the epoxy and a wooden rod is inserted into the cell from which the plug is to be removed and removed from the cell. The honeycomb was exposed at about 70 ° C. for about 1 hour. The final, hardened stopper depth was about 3 mm.

Although the present invention has been described in detail with reference to the specific embodiments illustrated, it should not be considered as being limited to these, and without departing from the spirit of the invention and the scope of the appended claims. It should be understood that it may be used in the method described above.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing selected honeycomb cells that are plugged by capillary action.

1a is a schematic diagram showing a selected honeycomb cell plugged by capillary action.

FIG. 2 is a schematic diagram showing the sealing material applied as a continuous line obliquely across the cross section of the honeycomb.

FIG. 2a is a schematic diagram showing the seal applied as a continuous line obliquely across the honeycomb cross section.

FIG. 3 schematically shows a honeycomb cell which is plugged by masking the cell to be finally opened with a temporary material, and the cell to be plugged is filled with a sealing material by capillary action and then removed. Figure

FIG. 3a is a schematic showing a honeycomb cell that is plugged by masking the cell that is ultimately opened with a temporary material, and the cell to be plugged is filled with sealing material by capillary action and then removed. Figure

FIG. 3b schematically shows the honeycomb cells which are plugged by masking the cells which are finally opened with a temporary material and which cells to be plugged are filled with sealing material by capillary action and then removed. Figure

FIG. 3c is a schematic showing a honeycomb cell that is plugged by masking the cell that is ultimately opened with a temporary material, and the cell to be plugged is filled with sealing material by capillary action and then removed. Figure

FIG. 4 shows the honeycomb cell with the cell masked and plugged, FIGS. 3 to 3
Fig. 4c is a schematic view similar to Fig. c, wherein the mask is in the form of a single part.

FIG. 5 is a schematic diagram showing a honeycomb cell with a plug having a wedge-shaped sealing material.

FIG. 5a is a schematic diagram showing a honeycomb cell with a plug having a wedge-shaped sealing material.

──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D019 AA01 BA01 BA05 BA13 BA16 BB01 BB07 BC05 CA01

Claims (12)

[Claims] 1. A method of plugging a honeycomb cell, comprising: (a) providing a honeycomb having an inlet end and an outlet end, and having a number of cells extending from the inlet end to the outlet end; b) providing a sealant; and (c) guiding the sealant to the preselected honeycomb cell opening by capillary action to form a plug at the preselected cell opening. And b. A method comprising: 2. The method of claim 1, wherein said sealant is selected from the group consisting of epoxy, silicone, cement, ceramic, urethane, thermoplastic, and combinations thereof. 3. The method according to claim 2, wherein the sealing material is an epoxy material. 4. The sealing material is supplied as a continuous linear pattern that crosses openings of a plurality of preselected cells, and is guided to the openings of the preselected cells to form the sealing material. 2. A method according to claim 1, wherein a plurality of cells can be drawn into openings of the plurality of cells. 5. The sealing material according to claim 4, wherein said sealing material is an epoxy material.
The described method. 6. The method of claim 4, wherein the seal comprises a heat treated, substantially entirely ceramic filter. 7. The entire end of the honeycomb is plugged, the plug is sucked into all of the cells, and selected cells are inserted and filled after the cells are filled. The method of claim 1 including a rod that is removed to empty the cell. 8. The method of claim 7, wherein said rod is wooden and disposable. 9. The cell opening that should not be plugged is masked with an instable material before the seal is directed to the preselected cell opening, and a seal is applied to the preselected cell opening. 2. The method of claim 1 wherein said unstable material is removed after being applied. 10. The method of claim 9, wherein said unstable material is selected from the group consisting of low melting waxes and thermoplastics. 11. A method for plugging a honeycomb cell, comprising: (a) having an inlet end surface and an outlet end surface, defining a cell wall, extending from the inlet end surface to the outlet end surface; Providing a honeycomb having a number of cells having a preselected cell opening to be plugged and plugged; and (b) having a region corresponding to the opening on a particular surface of the honeycomb, As a thermoplastic polymer preform, a region corresponding to the opening to be plugged has a thermoplastic sealing material, and the sealing material has a dimension that can be securely fitted to the opening of the honeycomb cell to be plugged. And (c) positioning the preform on the surface of the honeycomb having the preselected cell openings and inserting the thermoplastic sealant into the preselected cell openings. The pre-selected cell openings are heated to deform the thermoplastic seal and join the pre-selected cell openings, thereby ensuring that the selected cell openings are positioned. Producing a plugged honeycomb having a closed plug. 12. The sealing material is an epoxy having the cured outer coating over an uncured material in a cured outer coating, wherein the outer coating is formed of the pre-formed cell. 12. The method of claim 11, wherein the mantle breaks when inserted into the cell, thereby allowing the uncured material to plug the preselected cell.