JPS6171815A - Composite ceramic filter and preparation therefor - Google Patents

Abstract

PURPOSE:To obtain a composite ceramic filter having relatively large mechanical strength and easy to manufacture, by providing a bottomed cylindrical ceramic filter layer between two porous bottomed cylindrical ceramic supports. CONSTITUTION:A ceramic filter 1 consists of an outer cylindrical part 2 as a first bottomed cylindrical support, an inner cylindrical part 3 as a second bottomed cylindrical support and the filter layer 4 provided between the outer cylindrical part 2 and the inner cylindrical part 3. The filter layer 4 is filled with a ceramic powder. As the ceramic constituting the supports and the filter layer, alumina or cordierite is used.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a bottomed filter that allows selective outflow or passage of a fluid having predetermined characteristics from a fluid-like mixture. Such filters include filters or filters that allow selective passage of particles of a given chemical composition in a fluid mixture, and particles of a given chemical composition in a fluid mixture. An example of this is a catalytic filter that converts a fluid with certain characteristics (such as incomplete combustion products) into a complete combustion product form and allows it to flow out. [Prior art] Ceramic filter Ceramic filters for temperature control consisting of a porous bottomed cylindrical body are known (for example, Japanese Patent Laid-Open No. 55-1
19412-4 and JP-A-55-137021-
Publication No. 2). In this known ceramic filter made of a bottomed cylindrical body, the wall portion of the cylindrical body is thick at each portion in the thickness direction. has a uniform pore diameter, composition, etc. In other words, in the above-mentioned known ceramic filter made of a bottomed cylindrical body,
The wall of the cylindrical body has substantially uniform filter characteristics throughout its thickness. [Problems to be Solved by the Invention] However, in this type of conventional bottomed cylindrical ceramic filter, the wall of the cylindrical body is substantially uniform throughout the thickness direction of the filter. However, if a large mechanical strength is to be achieved, it becomes necessary to increase the P overpressure, etc. The present invention was developed in view of the above-mentioned points. The object is to provide a composite ceramic filter made of a bottomed cylindrical body that has a filtration layer with desired filter characteristics, has relatively high mechanical strength, and is easy to manufacture. [Means for Solving the Problems] According to the present invention, the above object is to provide a ceramic porous first bottomed cylindrical support whose outer surface is supported on the inner surface of the ceramic porous first bottomed cylindrical support. Achieved by a composite ceramic filter having a ceramic bottomed cylindrical filtration layer provided between the first and second supports so that the inner surface is supported on the outer surface of the second bottomed cylindrical support. be done. [Operations and Effects] The composite ceramic filter of the present invention has 1. ### The outer surface is supported on the inner surface of a first ceramic porous cylindrical support, and the inner surface is supported on the outer surface of a second ceramic porous cylindrical support. 5 has a bottomed ceramic cylindrical filtration layer provided between the first and second supports. 211- and the second support can impart sufficient mechanical strength to the filtration layer, so the mechanical strength of the filtration layer itself can be increased by I
The filtration layer can be made thin or made of ceramic having the desired catalytic activity or chemical properties without sacrificing quality, and the desired filter characteristics can be imparted. Moreover, the composite ceramic filter of the present invention is. The inner surface of the ceramic B5 porous qt first bottomed cylindrical support and the ceramic fissure porous second bottomed cylindrical support - and &
5. It can be easily manufactured by applying a combustible binder to form a ceramic M filter 1 between two supports. [Example] Next, a preferred example according to the present invention will be described based on the drawings.

DETAILED DESCRIPTION OF THE INVENTION The figure shows a composite ceramic filter 1 according to a preferred embodiment of the present invention. The ceramic filter l has an outer cylinder part 2 as a first bottomed cylindrical support and an inner cylinder part 3 as a second bottomed cylindrical support. It also includes a filtration layer 4 provided between the outer cylinder part 2 and the inner cylinder part 3. The outer cylinder part 2 made of porous ceramic has a hemispherical bottom part 7 on one end 6 side of the cylindrical main body part 5, and has a flange part 9 at the open end 11I8@. A filtration layer 41 filled with ceramic powder is closely supported by the entire inner surface 11 of the outer cylindrical portion 2 at its outer surface 10, and has a hemispherical shape on the one end 13 side of the cylindrical main body 12. It has a bottom portion 14 and is open at the other end 15 side. In addition, 1g of t-1 superlayer! The ceramic powder constituting the outer and cylindrical portion 2.4 may be partially or wholly sintered.
It may be sintered and fixed to the porous ceramic constituting No. 3. The cylindrical portion 3 made of porous ceramic supports the entire inner surface 17 of the filtration layer 4 with its entire outer surface 16, and has a hemispherical bottom portion 20 at one end 19 of its cylindrical body portion 18; The pore diameter of the outer cylinder part 2 and the inner cylinder part 3, which are open on the other end 21 side and are made of porous ceramic, is formed between the filled ceramic material powder forming the F:i static layer 4. If the size of the passage that allows the selective passage of fluid is smaller than C, it is larger than the "pore diameter of F1 layer 4 (made of powder)", and the composite ceramic filter l
The upper limit of the particle size of particles in the fluid that can pass through the filtration layer 4 is
It is defined by the pore size of d) Ceramic powder constituting the hot water layer 4 is easily 2.3
When the ceramic powder is filled in between the particles, the particle size of the ceramic powder is larger than the pore size of the outer cylinder part 2 and the inner cylinder part 3, so that the filtration layer 4 is 4J [during filtration and backwashing]. There is no possibility that the ceramic powder will flow out through the pores of the outer cylindrical part 2 and the inner cylindrical part 3. In addition, even if the pore diameter of the outer cylinder part 2 is the same as the pore diameter of the inner cylinder part 3,
It may be larger or smaller than the pore i of the inner cylinder part 3.
・. During filtration, the pore diameters of the outer cylinder part 2 and the inner fg part 3 are set so that the pressure loss in the pores of the outer cylinder part 2 and the pores of the inner cylinder part 3 can be substantially ignored. Sufficiently larger than the pore diameter. -1 The outer cylinder part 2 and the inner cylinder 1153 are made of materials that have sufficient mechanical strength to withstand the filtration pressure. Apply the desired σ and thickness depending on the degree of sintering, pore diameter, etc. The pore diameter of the filtration layer 4 can be adjusted by changing the average particle size of the ceramic particles constituting the FA eyebrow 4 and the blending ratio of large and small particles. The thickness of the filtration layer 4, in other words, the distance between the inner surface 11 of the outer cylinder 2 and the outer surface 16 of the inner cylinder 3 is the thickness of the filtration layer 4 that penetrates between the inner and outer surfaces 17 and 10 of the FlA layer 4. Preferably, the size of the smallest diameter portion of each pore is smaller than a given size, and among the pores that are open on one surface of the filtration layer 4, for example, one inner surface, preferably as much as possible. The pores are selected so that they penetrate to the outer surface 10. The type of ceramic that constitutes the outer cylinder 2, inner cylinder 3, and filtration rt44 is determined according to the type and size of the slurry to be FA. ,
Particles in a fluid that should not be treated 〒Flow 1 body h14
It is selected according to the type and size of the filter, the temperature of the fluid to be subjected to FA during filtration, and the KF filtration pressure, and even if they are the same,
They may be different from each other or may be partially the same. Outer cylinder 2. For example, alumina or cordierite is used as the ceramic material constituting the inner cylinder 3, and alumina or cordierite is used as the ceramic material constituting the first layer. Note that the flange portion 9 is a portion to which the composite ceramic filter 1 is to be supported or fixed, and may be omitted depending on the case. Also, the cross-sectional shape of the tube 2.3 is oval instead of circular.
It may also be a polygonal shape. Furthermore, in the composite filter 1, the bottom 14 of the filtration layer 4 is made thicker than the cylindrical main body 12, or the pore diameter of the bottom s14 is made extremely small, so that only the cylindrical main body 12 actually functions as a filtration layer. It's okay. In the composite ceramic filter 1 configured as above,
Since the FMS 4, which defines the filter characteristics, is supported from both sides by the ceramic inner and outer cylinders 3.2, the ceramic filter layer is made of suitable material and thickness to satisfy only the requirements regarding the filter characteristics. may be used. As a result, the composite ceramic filter l has relatively high mechanical strength, yet can exhibit the desired filter properties suitable for a wide range of applications. 5. The composite ceramic filter configured as above 1.
Preferably, one example can be easily produced by the following procedure. First, ceramic material powder hardened with a suitable combustible binder is filled into the space between the inner and outer cylinders 3.2 held in a predetermined positional relationship by appropriate holding means (hereinafter referred to as [
When the binder-bonded ceramic] has fluidity, the binder-bonded ceramic is appropriately pressed into the outer cylinder 2, and then the inner cylinder 3 is pushed into the binder-bonded ceramic to an appropriate depth to form the inner and outer cylinders 3. , a drop of binder-bonded ceramic may be placed between the two. A binder-bonded ceramic is then placed between the inner and outer cylinders 3.2, and the composite ceramic filter is formed by heating the material to an appropriate temperature to burn off the combustible binder. In the above, one example of a combustible binder is ``e''. PVA, waste liquid, etc. are used. In addition, in the above-mentioned firing and chopping steps, the ceramic material powder is sintered at a temperature of It is also possible to use ceramic material powder (which may be flammable) (which can be thermally decomposed into the desired ceramic in one step after firing the indica). (Even if the composite ceramic filter contains particles, it may be burned out at the same time in the indashing and chopping steps to artificially form pores in the filtration layer.) Layer +-2 as shown in Figure 1 (instead of being a single layer 4, it can also be made of 2N or 2N layered as shown in Figure 2) or 3 layers (instead of a single layer 4) as shown in Figure 2. In the extraction of the i2 diagram, the Ramic filter 22 has two 11-pass I so 23, 2
No. 4 differs from each other in terms of the characteristics as a catalyst filter, the characteristics as a +WI Eat filter, and the filter characteristics regarding the particle size that is passed through yI. Therefore, the JQ composite filter 22 can have multiple filter functions that cannot be fulfilled by a single filtration 1 (1) in a compact configuration. , by using a hollow cylindrical jig having the same external shape as I#24 in place of the inner cylinder 3, and if desired, after reducing the fluidity of the binder bonded ceramic by heating etc. Furthermore, in the same manner as above, another binder-bonded ceramic layer for the filtration layer 24 is placed between the binder-bonded ceramic layer for the filtration layer 23 and the inner cylinder 3, and the combustible binder is burned off. be done.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory view of a composite ceramic filter according to a preferred embodiment of the present invention, and FIG. 2 is a cross-sectional explanatory diagram of a composite ceramic filter according to another preferred embodiment of the present invention. 1.22...Composite ceramic filter. 2... Outer tube. 3...Inner cylinder. 4.23.24...filtration layer. Figure 2

Claims (5)

[Claims] (1) The outer surface is supported on the inner surface of a first ceramic porous cylindrical support, and the inner surface is supported on the outer surface of a second ceramic porous cylindrical support. A composite ceramic filter having a ceramic bottomed cylindrical filtration layer provided between first and second supports so as to (2) The filter according to claim 1, wherein the filtration layer consists of one substantially homogeneous layer. (3) The filter according to claim 1 or 2, wherein the filtration layer is a laminate of two or more bottomed cylindrical layers having different filtration characteristics. (4) Ceramic integrated with a combustible binder between the inner surface of the first ceramic porous cylindrical support and the outer surface of the second ceramic porous cylindrical support. A method for manufacturing a composite ceramic filter, comprising the steps of: arranging material granules in a bottomed cylinder; and burning off a combustible binder to form a ceramic filter between first and second supports. (5) The method of claim 4, wherein the ceramic material particles include combustible particles.