JPS6356816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a multilayer hollow filter having a plurality of filter layers having different particle size distributions.

(Prior art) Cylindrical hollow filters formed and fired with various granules have been used for the purpose of duct filtration of exhaust gas from garbage incinerators, etc.; Conventional molding methods could only produce a homogeneous single layer, so reducing the particle size of the filter layer to filter fine particles increases filtration resistance, and also reduces filtration resistance. There was a problem that when the wall thickness was reduced, the necessary strength could not be maintained.

(Purpose of the Invention) The present invention was completed with the aim of solving these problems and providing a method for manufacturing a multi-layer hollow filter having multiple filter layers with sufficient strength and high filtration efficiency. be.

(Structure of the Invention) The present invention produces a first filter layer by inserting an intermediate mold between an inner mold and an outer mold, filling one of the inner and outer double cavities with a filter molding material, and compression molding with a rammer. a second filter layer joined to the first filter layer by gradually pulling up the hollow space, filling the other gap with another filter molding material having a different particle size, and compression-molding this with a rammer. The method is characterized in that the molded body is molded, and after demolding, the molded body is fired.

(Example) Next, the present invention will be explained in detail using the illustrated molding apparatus. 1 is a cylindrical inner mold, and the inner mold 1 is combined with a cylindrical outer mold 2 which is divided into two parts. It is installed in the center of potter's wheel 3. Then, while rotating the potter's wheel 3 at a low speed, the filter molding material is gradually dropped and filled into the lower part of the cavity, and at the same time, the rammer 4
is moved up and down to compression mold the filter molding material to a constant degree of compaction. Filter molding materials include, for example, granular materials such as alumina, silicon carbide, porcelain, silica sand, and mullite with a particle size of approximately 50μ to 1000μ, in addition to water glass, CMC, dextrin, etc.
A mixture of a solidifying agent such as a ceramic flux or a glass flux at a ratio of 10 to 20% can be used, and the compression force of the rammer is, for example, 100 kg/
It should be about cm ² . When compression molding is performed to a predetermined height in this way, the inner mold 1
A thin cylindrical middle mold 5 is inserted between the outer mold 2 and the outer mold 2, and the middle mold 5 is sandwiched between the inner and outer molds to form double inner and outer voids 6 and 7. At this time, in order to stably hold the middle mold 5 with respect to the inner mold 1, it is preferable to interpose a guide 8 as shown in the figure. Next, a funnel 9 is placed on top of the outer mold 2, and while the inner mold 1, middle mold 5, and outer mold 2 are rotated simultaneously, the outer cavity 6 is filled with fine-grained filter molding material, and a rammer 10 is used. Compression molding is performed to form a first filter layer (A) of a predetermined length. Next, pull out the guide 8 as shown in Figure 3, cover the outer mold 2 with another guide 8' as shown in Figure 4, fix the lifting flange 11 to the upper end of the middle mold 5, and attach it to the lower surface. A lifting device 13 with a ball thrust bearing 12 is brought into contact with the inner mold 1, the middle mold 5, and the outer mold 2 while the inner mold 5 is gradually pulled up.
At the same time, the inner cavity 7 is filled with a coarse filter molding material having a different particle size from the filter molding material filled in the outer cavity 6, and compression molding is performed using the rammer 4 used earlier, and the second filter layer B is formed. will gradually form. At this time, medium size 5
If the pulling speed of the middle mold 5 and the filling speed of the filter molding material are controlled so that the pulling speed of the second filter layer B is almost equal to the molding speed of the second filter layer B, the filled filter molding material will be directly under the middle mold 5 and the rammer 4. The second filter layer B is pressed onto the circumferential surface of the first filter layer A by the compaction force and joined to the first filter layer A, thereby forming the second filter layer B. Thereafter, as shown in FIG. 5, if the end portion is formed using the end forming die 14, a multi-layer hollow molded body is obtained in the cavity portion, and when the molded body is finished forming, it is removed from the mold. This is fired at 1200-1450℃.
As shown in FIG. 6, the thus obtained multi-layer hollow filter has a first filter layer A with fine grains laminated integrally on the surface of a second filter layer B with coarse grains, and a second filter layer B with coarse grains. The first filter layer A filters fine particles because the filter layer B becomes a skeleton part that has a filtering function and maintains its strength.
can be made thinner, resulting in a multi-layer hollow filter with low filtration resistance and capable of filtering fine particles. In this example, the same filter molding material as the filter molding material initially introduced in the state shown in FIG. Molding was started from the inner cavity 6 first, but it is also possible to start molding from the inner cavity 7.Furthermore, a multilayer hollow filter having three or more layers can also be manufactured by the same means. Of course, as shown in the figure, the first filter layer A with fine grain size may be continuously formed not only on the peripheral surface but also over the end portion of the second filter layer B with coarse grain size.

(Effects of the Invention) As is clear from the above description, the present invention inserts a middle mold between an inner mold and an outer mold to form double internal and external voids, and utilizes either one of the voids. After the first filter layer was molded by rammer molding, the second filter layer was rammer molded into the other gap while gradually pulling up the middle mold.
The compressive force of the rammer when molding the second filter layer also acts on the first filter layer only in the lower portion of the medium mold, so that the second filter layer can be firmly bonded to the first filter layer. In addition, since the upper part of the first filter is protected by the middle mold during molding of the second filter, there is no risk of damage due to vibrations caused by the rammer, and a perfect multi-layer hollow filter can be manufactured at all times. A method for manufacturing a multi-layer hollow filter that can easily mass-produce multi-layer hollow filters with various filtration characteristics, such as a multi-layer hollow filter with low filtration resistance that can accurately filter fine particles. This is an extremely important contribution to the development of the industry.

[Brief explanation of drawings]

Figures 1, 2, 3, 4, and 5 are process explanatory diagrams of embodiments of the present invention;
FIG. 7 is a longitudinal sectional front view of a multilayer hollow filter obtained by the method of the present invention. 1: inner mold, 2: outer mold, 5: middle mold, 6: outer cavity, 7: inner cavity, A: first filter layer, B: second filter layer.

Claims (1)

[Claims] 1. A middle mold is inserted between an inner mold and an outer mold, and one of the inner and outer double voids is filled with a filter molding material and compression molded with a rammer to form a first filter layer. The second filter layer joined to the first filter layer is formed by molding, and then gradually pulling up the middle mold, filling the other gap with another filter molding material having a different particle size, and compression molding this with a rammer. A method for producing a multilayer hollow filter, which comprises molding, demolding, and then firing the molded body. 2. The method for manufacturing a multilayer hollow filter according to claim 1, wherein the pulling speed of the medium size is approximately equal to the molding speed of the second filter. 3. Claim 1, in which the cavity is cylindrical and the inner mold, middle mold, and outer mold are molded while rotating simultaneously.
A method for producing a multilayer hollow filter according to item 1 or 2.