JP2014057938A - Method of producing cylindrical filter, and cylindrical filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-performance cylindrical filter that has no internal structural defects and high reliability, and a method of producing the same.SOLUTION: A method of producing a cylindrical filter includes a winding step 101 in which nonwoven metal fabric is wound in plural layers to form a cylindrical shape, a sintering step 102 in which the wound nonwoven fabric undergoes sintering, and a compression step 103 in which the sintered nonwoven fabric is compressed.

Description

  The present invention relates to a method for manufacturing a cylindrical filter and a cylindrical filter, and more particularly, to a high-performance cylindrical filter having a filtration opening of a micron to submicron order size and a method for manufacturing the same.

  Conventionally, it is known that a cylindrical filter is made of a sheet-like material, and is manufactured by a method in which the material is formed into a cylindrical shape and then welded in the vertical direction (see Patent Document 1, paragraph 0003).

  In addition, a method of manufacturing a cylindrical filter that is integrally molded as a seamless porous metal filter by welding by compressing and sintering metal particles in a molding apparatus is known (for example, Patent Document 1). , Paragraph 0006).

JP-A-6-114220 (see, for example, claim 1, paragraphs 0003 and 0006)

Tosei Steel Pipe Co., Ltd. Homepage, pipes are made in this way, various steel pipe manufacturing flows (see medium and small diameter welded pipe making) (http://www.tohsei.co.jp/02/pipe.html) JFE Steel Corporation homepage, product information, manufacturing process (see UOE steel pipe manufacturing process) (http://www.jfe-steel.co.jp/products/koukan/kuutei/01/index.html) JFE Steel Corporation website, product information, manufacturing process (see bending steel pipe manufacturing process) (http://www.jfe-steel.co.jp/products/koukan/kuutei/02/index.html)

  However, in the case of a conventional cylindrical filter manufacturing method in which a sheet-shaped material molded into a cylindrical shape is welded in the vertical direction, the weld quality of the welded seam portion (seam portion) varies, resulting in internal variation. It has been difficult to produce a high-performance cylindrical filter with no defects in structure and high reliability. In addition, in the case of a conventional cylindrical filter manufacturing method in which metal particles are compression-molded and sintered in a molding apparatus, a static press that deforms and molds metal particles with different diameters at an ultra-high pressure in the pre-sintering molding process. In addition to the necessity of special molding equipment such as equipment, it is difficult to control the particle size of metal particles, and it is difficult to control sintering so that thermal cracking does not occur in the sintering process, etc. The manufacturing process has become complicated and difficult. The present invention has been made in view of these problems, and an object of the present invention is to provide a highly reliable high-performance cylindrical filter having no internal structural defect and a manufacturing method thereof.

  In order to solve the above-mentioned problem, a cylindrical filter manufacturing method according to the first aspect of the present invention is, for example, a cylindrical filter manufacturing method 100 shown in FIG. 1 and FIG. 2 is wound around the plurality of layers 2a and 2b to form a cylindrical shape; a sintering step 102 for sintering the wound nonwoven fabric 2; and a compression step 103 for compressing the sintered nonwoven fabric 2 Prepare.

  If comprised in this way, a highly reliable high performance cylindrical filter without the defect of an internal structure resulting from a joint, joint welding, etc. can be manufactured easily.

  Moreover, the manufacturing method of the cylindrical filter which concerns on the 2nd aspect of this invention is a manufacturing method of the cylindrical filter which concerns on the 1st aspect of this invention, for example, as shown in FIG.1 and FIG.2, winding. Step 101 includes a step 101 b of winding the nonwoven fabric 2 on the mandrel 10.

  When comprised in this way, since a nonwoven fabric can be wound along the outer peripheral surface of a mandrel and it can form in a cylinder shape, the cylindrical filter which has arbitrary dimensions and cross-sectional shapes can be manufactured with sufficient precision. .

  Moreover, the manufacturing method of the cylindrical filter which concerns on the 3rd aspect of this invention is a compression process as shown in FIG.1 and FIG.5 in the manufacturing method of the cylindrical filter which concerns on the 2nd aspect of this invention, for example. 103 includes a step 103 a of swaging the nonwoven fabric 2 between the mandrel 10 and the swaging jig 13; and further includes a step 103 b of releasing the swung nonwoven fabric 2 from the mandrel 10.

  When comprised in this way, since the nonwoven fabric 2 can be accurately compressed in the thickness direction of a cylindrical filter between the mandrel 10 and the swaging jig 13, the thickness of the cylindrical filter (thickness of the cylinder) Can be manufactured with a predetermined dimension t (see FIG. 6) with high accuracy. Moreover, the completed cylindrical filter can be obtained by removing the swung nonwoven fabric 2 from the mandrel 10.

  Moreover, the manufacturing method of the cylindrical filter which concerns on the 4th aspect of this invention is a manufacturing method of the cylindrical filter which concerns on any one aspect of the 1st thru | or 3rd aspect of this invention, for example, FIG. As shown, the diameter da of the non-woven fabric metal fiber forming the inner circumferential layer 2a of the multiple layers 2a, 2b is different from the diameter db of the non-woven fabric metal fiber forming the outer circumferential layer 2b of the multiple layers 2a, 2b. It is comprised so that it may become.

  When configured in this way, when the diameter db of the metal fiber of the outer peripheral layer 2b is smaller than the diameter da of the metal fiber of the inner peripheral layer 2a, the inner periphery 2i (see FIG. 6) from the outer periphery 2o (see FIG. 6) side. It is suitable for flowing the fluid to be filtered in the direction of thickness t (see FIG. 6) toward the side. At this time, in the case of producing a high-performance cylindrical filter with a fine filter opening size (size), a fine filtration surface (periphery 2o) having a fine filter opening size in the outer peripheral layer 2b of the cylindrical filter. ) Can be formed. On the other hand, in the inner peripheral layer 2a of the cylindrical filter that comes into contact with a jig such as the mandrel 10, a contact surface (inner periphery 2i) that has a smaller contact area (a larger diameter of the metal fiber) and is easy to be released can be formed. it can. For this reason, a high performance cylindrical filter can be easily manufactured compared with the conventional manufacturing method. When the diameter da of the metal fiber of the inner peripheral layer 2a is smaller than the diameter db of the metal fiber of the outer peripheral layer 2b, it is suitable for flowing the fluid to be filtered from the inner periphery 2i side to the outer periphery 2o side of the cylindrical filter.

  Moreover, the manufacturing method of the cylindrical filter which concerns on the 5th aspect of this invention is a manufacturing method of the cylindrical filter which concerns on the 4th aspect of this invention, for example, as shown in FIG.4 (B), winding In step 101 (see FIG. 1), a nonwoven fabric 2c is used in which the nonwoven fabric 2a forming the inner circumferential layer and the nonwoven fabric 2b forming the outer circumferential layer are configured as one continuous nonwoven fabric.

  When comprised in this way, since the cylindrical filter can be manufactured by continuously winding the single nonwoven fabric 2c, the cylindrical filter can be manufactured efficiently.

  Moreover, the manufacturing method of the cylindrical filter which concerns on the 6th aspect of this invention is a manufacturing method of the cylindrical filter which concerns on the 4th aspect of this invention, for example, as shown to FIG. 4 (A), winding In step 101 (see FIG. 1), a plurality of nonwoven fabrics 2a and 2b made of metal fibers having different diameters da and db are overlapped and wound.

  When configured in this manner, a plurality of metal fiber nonwoven fabrics 2a and 2b having different structural characteristics are sequentially wound around the mandrel 10 to produce a functional cylindrical filter having desired inclined internal structural characteristics. it can.

  A cylindrical filter manufacturing method according to a seventh aspect of the present invention is the cylindrical filter manufacturing method according to any one of the first to sixth aspects of the present invention. For example, FIG. As shown, a step 301 of plating palladium or palladium alloy on the inner or outer surface of the cylinder after the compression step 103 is provided.

  When comprised in this way, the high performance cylindrical filter which can be used as a hydrogen permeable filter for fuel cells, for example can be manufactured suitably.

  Moreover, the cylindrical filter according to the eighth aspect of the present invention is a cylindrical filter 1 that is seamlessly formed into a cylindrical shape by a nonwoven fabric 2 of metal fibers, for example, as shown in FIG. 6; An inner peripheral layer 2a (see FIG. 2) that forms the inner periphery 2i of the outer peripheral layer 2b (see FIG. 2) that forms the outer periphery 2o of the cylindrical filter, and a non-woven metal fiber that forms the inner peripheral layer 2a And a peripheral layer 2b made of metal fibers having a diameter db different from the diameter da; the nonwoven fabric 2 is compressed in the thickness t direction; and is provided as a cylindrical filter.

  When comprised in this way, a cylindrical filter can be provided as a highly reliable cylindrical filter which does not have an internal structural defect resulting from a seam. Moreover, since the outer peripheral layer 2b and the inner peripheral layer 2a are respectively constituted by non-woven fabrics having different metal fiber diameters da and db and are compressed in the thickness t direction, the cylindrical filter is provided in the thickness t direction. It can have an inclined internal structure and porosity corresponding to changes in the stiffness of the nonwoven fabric. For this reason, the cylindrical filter which has a desired filtration characteristic can be provided. In addition, since the nonwoven fabric 2 is provided by being compressed in the thickness t direction, the cylinder is oriented so that the opening direction (normal direction of the opening surface) of the filtration opening of the compressed nonwoven fabric 2 faces the thickness t direction. A shape filter can be provided. For this reason, it is possible to provide an excellent cylindrical filter with low permeation resistance (pressure loss) during filtration and high filtration performance.

  Moreover, the cylindrical filter according to the ninth aspect of the present invention is the same as the cylindrical filter according to the eighth aspect of the present invention, for example, as shown in FIG. The palladium or palladium alloy layer 3 is provided.

  When configured in this manner, a high-performance cylindrical filter that can be used, for example, as a hydrogen permeation filter for a fuel cell can be provided. At this time, the layer comprised with the nonwoven fabric can be used as the support structure of a palladium layer. The palladium layer is preferably formed on the surface of a nonwoven fabric composed of metal fibers having a small wire diameter among a plurality of nonwoven fabrics composed of metal fibers having different wire diameters (diameters). If comprised in this way, since the palladium or palladium alloy layer can be formed thinly, the transmittance | permeability of hydrogen can be made high.

  According to the method for manufacturing a cylindrical filter and the cylindrical filter according to the present invention, it is possible to provide a highly reliable high-performance cylindrical filter having no internal structural defect and a method for manufacturing the same.

FIG. 1 is a flowchart showing an example of a method of manufacturing a cylindrical filter according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of a winding process according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram showing an example of a winding process according to the first embodiment of the present invention. FIG. 4A is an explanatory diagram showing an example of a winding process according to the first embodiment of the present invention. FIG. 4B is an explanatory diagram illustrating an example of a winding process according to another embodiment. FIG. 5A is an explanatory diagram showing an example of the compression process according to the first embodiment of the present invention. FIG. 5B is an explanatory diagram showing an example of a mold release process according to the first embodiment of the present invention. FIG. 6 is an explanatory view showing an example of a cylindrical filter according to the second embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or similar members are denoted by the same or similar reference numerals, and redundant description is omitted. Further, for easy understanding, each drawing is shown in an exaggerated dimension shape different from the actual size as appropriate.

  With reference to FIG. 1, the manufacturing method of the cylindrical filter which concerns on the 1st Embodiment of this invention is demonstrated. The manufacturing method 100 of the cylindrical filter shown in FIG. 1 is equipped with the winding process 101 which winds the nonwoven fabric of a metal fiber and forms it in a cylinder shape. The winding process 101 includes, as its main process, an outer peripheral surface of a solid cylindrical mandrel 10 (see FIG. 2) made of unsintered stainless steel, for example, SUS316L nonwoven fabric 2 (see FIG. 2) or the like. It has the nonwoven fabric winding process 101b wound along the top. In other embodiments, a hollow cylindrical mandrel having an outer diameter having sufficient strength for use may be used. Preferably, the mandrel is made of a ceramic such as zirconia or alumina, which has a smaller coefficient of thermal expansion than stainless steel, which is a non-woven metal fiber wire. When the release material is added to the mandrel surface, the mandrel may be made of stainless steel. Further, it is preferably provided by a sintered body of partially stabilized zirconia (PSZ) or alumina. As described above, when the nonwoven fabric 2 is wound along the mandrel 10, the nonwoven fabric can be wound into a desired dimension and formed into a cylindrical shape with high accuracy. The “tubular shape (cylindrical shape)” is preferably a cylindrical shape. However, the “cylindrical shape (cylindrical shape)” can be arbitrarily changed according to the shape of the outer peripheral surface of the mandrel, and in other embodiments, for example, has a square cross section, a regular polygon cross section, etc. A filter may be formed in a cylindrical shape.

  Moreover, as long as the metal fiber of a nonwoven fabric is a material which can mutually sinter (diffusion joining), the fiber of arbitrary metal materials can be used. Further, a slightly semi-sintered nonwoven fabric may be used as long as it is within a limit range in which the nonwoven fabric can be wound and formed into a cylindrical shape. In general, a nonwoven fabric refers to a fabric in which fibers are accumulated in a certain direction or randomly and bonded or entangled by thermal, mechanical or chemical action. Therefore, in the present application, when referred to as “metal fiber nonwoven fabric”, metal fibers are accumulated in a certain direction or randomly and entangled to form a sheet (particularly referred to as “unsintered nonwoven fabric”, It can also be regarded as cotton made of metal fibers that are thinly stretched and formed into a sheet shape), and also includes a slightly semi-sintered sheet-like non-woven fabric as described above.

  The material of the metal fiber constituting the nonwoven fabric is typically stainless steel. Austenitic stainless steel is particularly preferable. It is because it is excellent in corrosion resistance and heat resistance. Further, since the linear expansion coefficient is relatively large (about 1.7 times that of carbon steel) as will be described later, it is easy to extract the mandrel after swaging. It is good also as a ferrite type and a martensite type. In particular, the martensite system is inferior to the austenite system in terms of corrosion resistance, but is excellent in terms of high strength. The material is appropriately selected according to the application.

  In the nonwoven fabric winding step 101b, the nonwoven fabric 2 (see FIG. 2) is wound on the mandrel 10 (see FIG. 2) in multiple layers. “Wound in a plurality of layers” typically refers to forming a metal fiber nonwoven fabric into a cylindrical shape over a plurality of turns, but beyond the starting end (one turn) of the metal fiber nonwoven fabric. It includes the case where the nonwoven fabric is wound and formed into a cylindrical shape with the number of turns less than two rounds. Even when the nonwoven fabric is wound with less than two turns, a highly reliable joint with no defects in the internal structure is realized by covering the winding end of the nonwoven fabric with multiple layers. can do.

  The winding step 101 includes a release material winding step 101a for winding the release sheet material 11 of alumina paper (see FIG. 2) around the mandrel 10 (see FIG. 2) before the nonwoven fabric winding step 101b. The alumina paper 11 can be provided by binding (binding) alumina fibers with an organic substance of about 5% by weight of the total weight of the alumina paper. By separating the alumina paper 11 with the alumina paper 11, the nonwoven fabric inner peripheral layer 2a (see FIG. 2) is provided. ) And the mandrel 10 can be prevented from being fixed by sintering and by subsequent swaging. The organic substance can be, for example, paper fiber. Moreover, since the organic substance which couple | bonds an alumina fiber is thermally decomposed by the 1st sintering process 102, the alumina paper 11 becomes weak and can be easily removed from the sintered nonwoven fabric.

  In the present embodiment, the non-woven fabric is wound around the mandrel 10 by winding the alumina paper 11 (see FIG. 2) preliminarily cut to 1.2 times the outer peripheral length of the mandrel 10 (see FIG. 2). The inner peripheral layer 2a (see FIG. 2) and the outer peripheral surface of the mandrel 10 are completely separated from each other so as to be easily released. In another embodiment, the alumina paper 11 may be wound around the outer periphery of the mandrel 10 with a roll length less than one turn. Also in this case, the alumina paper 11 is made to have a mandrel 10 with a gap that is less than one full length, so long as the inner peripheral layer 2a of the nonwoven fabric and the outer peripheral surface of the mandrel 10 are not bonded by diffusion bonding. It can be wound around to form a release material. Alternatively, the alumina paper 11 may be wound around the mandrel 10 just once. Alternatively, when the nonwoven fabric 2 and the mandrel 10 are provided with materials (for example, stainless steel and zirconia) that are difficult to be sintered (diffusion bonded) to each other, it is not necessary to use the alumina paper 11 as a release material. . In these cases, the inner peripheral surface 2i of the nonwoven fabric formed in a cylindrical shape (see FIG. 6) (hereinafter, reference numeral 2i appropriately indicates simply the inner periphery, inner peripheral surface or innermost peripheral layer of the nonwoven fabric layer. Is simply an outer periphery, an outer peripheral surface, or an outermost peripheral layer of the nonwoven fabric layer), and a discontinuous step does not occur due to the overlapping portion of the alumina paper 11. For this reason, the inner peripheral surface 2i of the nonwoven fabric can be formed as a smoother continuous surface.

  The cylindrical filter manufacturing method 100 of the present embodiment includes a first sintering step 102 for sintering the wound nonwoven fabric. The first sintering step 102 is a first step in which the non-woven fabric 2 wound around the mandrel (see FIG. 2) is heated to diffusely bond the metal fibers contacting each other inside the non-woven fabric 2. Bonding sintering step 102c. In the first sintering step 102, the sintering environment is changed to an oxygen-free atmosphere or a reducing gas atmosphere so that the nonwoven fabric can be sintered more strongly before the first bonding sintering step 102c. You may have the 1st atmosphere adjustment process 102a adjusted beforehand. When sintering is performed in an oxygen-free atmosphere or a reducing gas atmosphere such as hydrogen or formic acid, sintering failure due to an oxide film formed on the surface of the metal fiber is prevented, and the metal fiber is sintered more firmly. Can conclude. In addition, it is possible to prevent the occurrence of problems such as oxidative fixation of the nonwoven fabric due to inclusions on the contact surface between the nonwoven fabric and the release material (or mandrel). The first sintering step 102 is a first step in which the nonwoven fabric is heated for a certain period of time at a relatively low temperature below the melting temperature of the nonwoven fabric metal fibers after the atmosphere adjustment step and before the bonding sintering step. It has a preheating step 102b. The heating temperature is in the range of 400 degrees Celsius to 900 degrees Celsius, preferably in the range of 600 degrees Celsius to 800 degrees Celsius, and in this embodiment, 750 degrees Celsius. Further, the fixed time is in the range of 30 minutes to 120 minutes, preferably in the range of 40 minutes to 90 minutes, and in this embodiment is 60 minutes (1 hour). In the case of having a preheating step, fats and oils, moisture, inclusions and the like that adhere to the surface of the metal fiber and hinder sintering can be thermally decomposed and removed. For this reason, metal fiber can be sintered more strongly in the subsequent joining and sintering step.

  In the sintering step 102 of the present embodiment, the nonwoven fabric (workpiece) 2 wound around the mandrel (see FIG. 2) is sealed, and the workpiece 2 is disposed in a sealed container (muffle) that is shielded from the outside air. The workpiece 2 is sintered using an electric sintering furnace (muffle furnace) (not shown) that heats the entire hermetic container from the outside. In the first atmosphere adjustment step 102a of the first sintering step 102, nitrogen gas is first flowed into the sealed container to replace the air in the container, and then hydrogen gas is injected as a reducing gas into the sealed container. Adjust the atmosphere. Further, in the first preheating step 102b included in the first sintering step 102, the work 2 is heated at 750 degrees Celsius for 1 hour to remove an inhibitory substance that inhibits the sintering. Since the organic matter contained in the alumina paper 11 (see FIG. 2) used as the release material can be previously thermally decomposed and removed by the preheating step, the organic matter contained in the release material is removed in the bonding sintering step. Stable metal fibers can be sintered without being affected by thermal decomposition (pyrolytic substance).

  In the first bonding sintering step 102c included in the first sintering step 102 of the present embodiment, the workpiece 2 is in the range of 1000 degrees Celsius to 1300 degrees Celsius, preferably in the range of 1100 degrees Celsius to 1200 degrees Celsius, In the embodiment, heating is performed at 1190 degrees Celsius for a predetermined time. The predetermined time is in the range of 1 hour to 3 hours and 30 minutes, preferably in the range of 1 hour to 3 hours, and in this embodiment, 2 hours. In this embodiment, sintering is performed at 1190 degrees Celsius for 2 hours. In addition, the first sintering step 102 is cooled after the first bonding sintering step 102c, the first cooling step 102d for cooling the airtight container containing the work 2 by air cooling with a fan blow for 40 minutes, and cooling. A first replacement step 102e for injecting nitrogen gas into the sealed container and discharging the hydrogen gas therein is further included. In the present embodiment, the first sintering step 102 has been described as having an atmosphere adjustment step, a preheating step, a cooling step, and a replacement step, but in other embodiments, these steps are included. Alternatively, a cylindrical filter may be manufactured. In this case, a cylindrical filter can be manufactured more easily. In another embodiment, according to the wire diameter, material, etc. of the metal fiber of the nonwoven fabric to be sintered, the above-described sintering conditions (temperature) exemplified for the first sintering step 102 of the present embodiment. , Time, etc.) may be appropriately changed to sinter the nonwoven fabric.

  The manufacturing method 100 of the cylindrical filter of this Embodiment is equipped with the 1st compression process 103 which compresses the sintered nonwoven fabric. In the first compression step 103, the thickness t (see FIG. 6) of the cylindrical filter from the outer periphery 2o (see FIG. 5 (A)) of the sintered nonwoven fabric toward the axis of the winding axis of the nonwoven fabric winding. ) Compress the nonwoven fabric along the direction. By compression-molding the sintered nonwoven fabric, a cylindrical filter having a desired porosity and filtration opening size can be manufactured. When the sintered nonwoven fabric is compression-molded in the thickness t direction of the cylindrical filter as shown in this embodiment, the sintered nonwoven fabric is uniformly plastically deformed while having anisotropy. That is, in the present embodiment, the nonwoven fabric is plastically deformed exclusively in the thickness t direction, which is the normal direction of the opening surface of the filtration opening, and is uniformly compression molded. In this case, as in the case of a cylindrical filter manufactured by a conventional cylindrical filter manufacturing method in which metal particles are deposited between an inner mold and an outer mold of a conventional molding apparatus and pressurized from an opening, There is no variation in the filtration characteristics due to the non-uniform filling rate of the metal particles in the cylindrical filter in the axial direction (longitudinal direction). For this reason, while having desired filtration characteristics (porosity and filtration opening size), it is possible to produce an excellent cylindrical filter having excellent transmission characteristics and low pressure loss (transmission resistance). In particular, the porosity in the surface layer (outer periphery 2o or inner periphery 2i (see FIG. 6)) of the cylindrical filter that is plastically deformed by contact with a tool (swaging jig or mandrel) that can be regarded as a rigid body is accurately adjusted. be able to. In addition, since it is not greatly plastically deformed in the axial direction (longitudinal direction), the completed cylinder has often been a problem in the cylindrical filter manufactured by the conventional method of compressing and sintering metal particles. Overcoming the brittleness problem of shaped filters, it is possible to produce cylindrical filters with excellent mechanical properties.

  In the present embodiment, a cylindrical filter is manufactured by compression-molding a sintered nonwoven fabric. Therefore, a cylindrical filter having a seam in which a conventional sheet-like material is molded into a cylindrical shape and welded in the axial direction. Thus, a highly reliable seamless cylindrical filter that does not have defects in the internal structure as in the case of the above can be produced. Here, “seamless” means that there is no seam by seam in the longitudinal direction (axial direction) of the cylinder. Furthermore, the thickness t (see FIG. 6) of the cylindrical filter can be made thinner as compared with a cylindrical filter manufactured by a conventional manufacturing method in which metal particles are compressed and sintered. While having filtration characteristics (porosity and filtration opening size), an excellent cylindrical filter having excellent transmission characteristics and small pressure loss (transmission resistance) can be produced. Moreover, there is no restriction | limiting in the length of the mandrel 10 (refer FIG. 2) used for manufacture of a cylindrical filter, and since the diameter of the mandrel 10 can be provided as small as possible, the conventional metal particle is compressed and sintered. A longer and thinner cylindrical filter can be easily manufactured compared to a cylindrical filter that can be manufactured by the method.

  The compression step 103 can include a first swaging step 103a for swaging (corrective compression molding) the sintered nonwoven fabric between the mandrel and the swaging jig. In the first swaging step 103a, the nonwoven fabric 2 (see FIG. 5 (A)) sintered between the swaging jig 13 (see FIG. 5 (A)) and the mandrel 10 (see FIG. 5 (A)) is used. Sweat the nonwoven fabric with a narrow pressure. Details of the swaging step 103a will be described later.

  Further, the compression step 103 may include a first release step 103b for releasing the compression-molded nonwoven fabric from a jig such as a mandrel. In the first release step 103b, the nonwoven fabric 2 (FIG. 5B) sintered from the mandrel 10 by applying a shearing force between the release material 11 (see FIG. 2) and the mandrel 10 (see FIG. 5B). (See below) and remove. The mold release process 103b can further include a mold release material removal process (not shown) for removing the mold release material (alumina paper) 11 from the nonwoven fabric. The organic matter contained in the release material (alumina paper) 11 of the present embodiment is thermally decomposed by sintering, and the release material 11 is made brittle by swaging. Therefore, the sintered nonwoven fabric 2 is easily separated from the mandrel 10. The mold release material (alumina paper) 11 can be easily removed from the sintered nonwoven fabric 2. Details of the mold release step 103b will be described later. The mold release process can be performed at room temperature (room temperature), but the whole including the mandrel and non-woven fabric layer is added to 100 degrees Celsius to 300 degrees Celsius using the difference in linear expansion coefficient between the non-woven fabric and the mandrel. You may go warm. The mandrel can be removed more easily.

  The cylindrical filter manufacturing method 100 of the present embodiment includes a second sintering step 201 similar to the first sintering step 102. In the second sintering step 201, the non-woven fabric is sintered by re-sintering the non-woven fabric of metal fibers that are more closely contacted to each other and increased in contact by being compression-molded in the first compression step 103. The result can be made stronger. In the second sintering step 201, the non-woven fabric from which the release material 11 (see FIG. 2) has already been removed in the first releasing step 103b can be inserted and sintered again on the mandrel 10 (see FIG. 2). .

  In the second bonding / sintering step 201c of the second sintering step 201, the non-woven fabric was joined and sintered (diffusion bonding) without using the release material 11 (see FIG. 2). In consideration of a decrease in the diameter (sintering) of the nonwoven fabric, the sintering can be performed at a sintering temperature lower than that of the first bonding sintering step 102c included in the first sintering step 102. In this case, joint sintering is performed at a slightly lower sintering temperature than that in the first sintering step 102, so that the mandrel 10 (see FIG. 5B) and the nonwoven fabric 2 (see FIG. 5B) after joint sintering. It has been confirmed by the present inventor that the mold can be easily released (see B). For example, this effect can be obtained by setting the bonding sintering temperature of the second sintering step 201 to a temperature that is 20 degrees Celsius lower than that of the first sintering step 102. The temperature range to be lowered to obtain this effect can be, for example, a range of 10 degrees Celsius to 120 degrees Celsius, and a narrower range of 20 degrees Celsius to 50 degrees Celsius. In the present embodiment, the cylindrical filter manufacturing method 100 has been described as including the second sintering step 201. However, in other embodiments, the cylindrical filter manufacturing method 100 includes the second sintering step 201 without including the second sintering step 201. A cylindrical filter may be manufactured by only one sintering step 102. In this case, a cylindrical filter can be manufactured more easily.

  The manufacturing method 100 of the cylindrical filter of this Embodiment is provided with the 2nd compression process 202 similar to a 1st compression process. The second compression step 202 is the last compression step in the cylindrical filter manufacturing method 100 of the present embodiment, and the dimensions of the inner peripheral surface and the outer peripheral surface of the sintered nonwoven fabric are set in the finished cylindrical filter. The dimensions of the peripheral surface 2i and the outer peripheral surface 2o (see FIG. 6) can be accurately finished. In the second swaging step 202a of the second compression step 202, since the release material (alumina paper) 11 has already been removed in the first release step 103b, the inner periphery 2i of the nonwoven fabric is the release material 11. Compressed so as to completely match the outer periphery of the mandrel 10 (see FIG. 5A) For this reason, the inner periphery 2i of the cylindrical filter can be formed smoothly and with high dimensional accuracy without being affected by the release material 11. Further, as already described, the mandrel can be pulled out relatively easily due to the difference in the linear expansion coefficient based on the difference in the metal fibers of the nonwoven fabric and the material of the mandrel. As described above, by repeating the sintering step and the compression step a plurality of times, it is possible to provide stronger sintering and more accurate dimensional shape of the cylindrical filter. In other embodiments, the number of repetitions of the sintering step and the compression step may be two times or more, for example, three times. Alternatively, in still another embodiment, the cylindrical filter may be manufactured only by the first compression step 103 without providing the second compression step 202. In this case, a cylindrical filter can be manufactured more easily.

  The cylindrical filter manufacturing method 100 according to the present embodiment includes any one of the inner peripheral layer and the outer peripheral layer surfaces 2i and 2o (see FIG. 6) of the cylindrical filter after the final compression step (second compression step 202). There is provided a palladium or palladium alloy plating step 301 for applying palladium or palladium alloy plating 3 (see FIG. 6) to the crab (particularly on the side of the layer using metal fibers having a small wire diameter). When the filtration opening on the surface of the cylindrical filter is sealed with palladium or palladium alloy plating, the palladium or palladium alloy plating layer functions as a hydrogen permeable membrane. Can be used as The palladium alloy can be, for example, an alloy of palladium and silver, copper or the like. According to the manufacturing method 100 of the cylindrical filter of the present embodiment, since the filtration opening size of the cylindrical filter can be manufactured in a micron order or a submicron order, a very thin film thickness is formed on the surface of the cylindrical filter. By simply performing palladium or palladium alloy plating, a filtration opening can be suitably sealed to produce a hydrogen permeable filter. In this case, the amount of rare metal palladium or palladium alloy used can be reduced. In other embodiments, the cylindrical filter may be manufactured without applying palladium or palladium alloy plating. Also in this case, an excellent cylindrical filter having desired filtration characteristics (porosity and filtration opening size) and excellent permeation characteristics and low pressure loss can be produced.

  With reference to FIG. 2, the winding process which concerns on this Embodiment is demonstrated in detail. The mandrel 10 provided in the winding device 20 that realizes the winding step 101 (see FIG. 1) of the present embodiment, and the mandrel chuck 10a that supports the mandrel so as to be detachable and rotatable with respect to the winding device 20 are free. FIG. 2 shows the first and second winding rollers 12a and 12b that are rotatably supported. The winding rollers 12a and 12b are further arranged with a third winding roller 12c (see FIG. 3) around the mandrel 10 at an angular interval of 120 degrees. The first to third winding rollers 12a, 12b, and 12c are each driven by an air cylinder (not shown) so as to be capable of moving forward and backward (stroke) toward the axis of the rotating shaft of the mandrel 10. Note that the winding device can be provided with a difference different from the example shown in the range within which the winding process of the present embodiment can be realized. In the present embodiment, the cylindrical filter 1 having a diameter of the outer periphery 2o of 12.7 mm, a diameter of the inner periphery 2i of 11.04 mm, a thickness t of about 0.8 mm, and an axial length of 200 mm (see FIG. 6). The mandrel 10 is provided at 11.04 mm where the outer diameter of the mandrel 10 coincides with the diameter of the inner circumference 2i of the tubular filter 1.

  In the present embodiment, first, alumina paper 11 as a release sheet material is wound around the mandrel 10. In order to wind the alumina paper 11, the winding rollers 12a and 12b are moved backward to provide a gap between the mandrel 10 and the winding rollers 12a and 12b. In the present embodiment, an elastic sheet (not shown) is overlapped on the brittle alumina paper 11 from the outside, and the alumina paper 11 and the elastic sheet are wound between the winding rollers 12a and 12b and the mandrel 10 with a narrow pressure. Start winding. In this case, the winding rollers 12a and 12b do not come into direct line contact with the alumina paper 11, and the load to which the elastic sheet is applied can be distributed over a wider range. There is no end to it. For this reason, the alumina paper 11 can be uniformly wound around the mandrel 10. The elastic sheet may be provided transparently. In this case, the state of the alumina paper 11 being wound can be wound while being visually recognized from the outside of the elastic sheet. In addition, it is good also considering the nonwoven fabric used as an inner peripheral layer instead of an elastic sheet. In that case, the process of removing the elastic sheet can be omitted.

  In the present embodiment, the pressure applied by the winding rollers 12a and 12b when winding the alumina paper 11 is set to a pressure lower than the pressure applied when winding the nonwoven fabric 2 of metal fibers. This is because when the pressure is increased, the alumina fiber is broken and the shape cannot be maintained. In the present embodiment, the pressure applied by the winding roller can be set to, eg, 0.05 MPa (equivalent to 140 N per narrow pressure length of 270 mm). With this applied pressure, the winding rollers 12 a and 12 b are advanced toward the axis of the mandrel 10, and the mandrel 10 is rotated while the elastic sheet (not shown) and the alumina paper 11 are compressed between the mandrel 10. The alumina paper 11 is wound around a mandrel.

  In the present embodiment, the mandrel 10 is provided so as to be rotated by applying a necessary rotational torque by a manual handle (not shown) connected to the mandrel chuck 10a. In this case, the manufacturer of the cylindrical filter can appropriately perform the winding while confirming the processing reaction force transmitted to the manual handle. On the other hand, in another embodiment, the mandrel 10 may be mechanically rotated by a motor (not shown) that is optionally rotationally controlled. In this case, the winding process can be realized more efficiently. After the alumina paper 11 is rounded by winding, pressure is applied by the third winding roller 12c (see FIG. 13) and the mandrel 10 is rotated to cause the alumina paper 11 to move to the mandrel 10. Process to adhere. The elastic sheet (not shown) can be removed from the winding device 20 after the alumina paper 11 is wound.

Subsequently, the non-woven fabric 2a (weight per unit area 150 g / m ² ) made of metal fibers made of stainless steel (SUS316L) with a wire diameter (average cross-sectional diameter) da = 6.5 μm forming the inner peripheral layer of the cylindrical filter is described above. As described above, the paper is wound on the mandrel 10 from above the wound alumina paper 11. In FIG. 2, the nonwoven fabric 2a which cuts out a part of nonwoven fabric 2b which forms the outer peripheral layer of a cylindrical filter for description, and forms an inner peripheral layer is shown. The wire diameter da of the metal fiber can be arbitrarily selected together with the material and the basis weight so as to obtain desired filtration characteristics (porosity and filtration opening size), rigidity, and transmission characteristics. The non-woven fabric 2a forming the inner peripheral layer of the cylindrical filter is previously wound with a roll width of 270 mm sufficient for manufacturing the axial length of the cylindrical filter of 200 mm, and the roll length is wound around the mandrel by 7.5 turns. It is cut into a length (300 mm) that can be prepared.

  The winding of the nonwoven fabric 2a forming the inner circumferential layer is a state in which the alumina paper 11 wound between the first and second winding rollers 12a and 12b and the mandrel 10 and the nonwoven fabric 2a are overlapped and narrowed. By rotating the mandrel 10, the nonwoven fabric 2a is first wound on the alumina paper 11 only once. After the nonwoven fabric 2a is wound once, the third winding roller 12c (see FIG. 13) is added and the nonwoven fabric 2a is moved to the mandrel 10 (alumina paper 11 by the first to third winding rollers 12a, 12b, 12c. ) The entire length (7.5 laps) of the nonwoven fabric 2a is wound around the outer circumference of the mandrel 10 while being pressed upward. After the entire length (7.5 laps) of the nonwoven fabric 2a is wound on the outer circumference of the mandrel 10, the applied pressure of each of the first to third winding rollers 12a, 12b, 12c is 0.2 MPa (narrow pressure length). The pressure is increased to about 600 N per 270 mm, and the mandrel is rotated about 20 times to form the nonwoven fabric 2a into a cylindrical shape. Thus, until the full length of the nonwoven fabric 2a which forms the inner peripheral layer of the cylindrical filter is wound around the mandrel 10, the pressure applied by the first to third winding rollers is wound as a relatively low pressure. Thereby, it can prevent that the nonwoven fabric 2a which forms the alumina paper 11 and an inner peripheral layer is crushed (plastically deformed).

Similarly, the non-woven fabric 2b (weight per unit area 150 g / m ² ) made of metal fibers made of stainless steel (SUS316L) with a wire diameter (average cross-sectional diameter) db = 2 μm forming the outer peripheral layer of the cylindrical filter is as described above. The tubular filter wound on the mandrel 10 is further overlapped on the nonwoven fabric 2a forming the inner peripheral layer of the cylindrical filter. Similarly, the wire diameter db of the metal fiber can be arbitrarily selected together with the material and the basis weight so that desired filtration characteristics (porosity and filtration opening size), rigidity and permeation characteristics can be obtained. The non-woven fabric 2b forming the outer peripheral layer of the cylindrical filter is previously wound around the mandrel by a roll length of 22.6 rounds so that the roll width is 270 mm sufficient to manufacture the axial length of 200 mm of the cylindrical filter. It is cut into a length (900 mm) that can be prepared. When the non-woven fabric 2b forming the outer peripheral layer of the cylindrical filter is wound around the mandrel 10, the alumina paper 11 already wound on the mandrel 10 and the non-woven fabric 2a forming the inner peripheral layer are first to thru. The pressure applied by the third winding rollers 12a, 12b, and 12c (see FIG. 3) is dispersed. For this reason, the alumina paper 11 and the nonwoven fabric 2 are crushed even if the pressure applied by the winding roller when winding the nonwoven fabric 2b forming the outer peripheral layer is 0.2 MPa (equivalent to 600 N per narrow pressure length of 270 mm) from start to finish ( There is no plastic deformation in the thickness direction).

  With reference to FIG. 3, the winding process which concerns on this Embodiment is further demonstrated. FIG. 3 shows an alumina paper 11 as a release material, a non-woven fabric 2a forming an inner peripheral layer of a cylindrical filter, and a non-woven fabric 2b forming an outer peripheral layer in the thickness direction by first to third winding rollers 12a, 12b and 12c. It is shown that it is pressed and is overlapped on the mandrel 10. The non-woven fabric 2a forming the inner peripheral layer and the non-woven fabric 2b forming the outer peripheral layer are wound around a plurality of layers, and the metal fibers are in contact with each other across the layers without causing a gap on the contact surface between the layers. In this manner, the nonwoven fabric 2 is pressed in the direction of the thickness t (see FIG. 6) of the cylindrical filter between the mandrel 10 and the first to third winding rollers and is formed into a cylindrical shape.

  With reference to FIG. 4, the winding process which concerns on this Embodiment is further demonstrated. As shown in FIG. 4A, in the winding step 101 (see FIG. 1) of the present embodiment, a plurality of nonwoven fabrics 2a made of metal fibers having different wire diameters (average cross-sectional diameters) da and db. 2b are sequentially stacked and wound on the outer peripheral surface of the mandrel 10. When a plurality of different types of non-woven fabrics 2a and 2b are wound in such a manner, a functional cylindrical filter having a desired inclined internal structure characteristic according to the difference in mechanical properties of the non-woven fabrics 2a and 2b is used. Can be manufactured. Moreover, there is no restriction | limiting in the number of the nonwoven fabrics to overlap | superpose, In other embodiment, the inner peripheral layer 2a of a cylindrical filter, the intermediate | middle layer (not shown), and the outer peripheral layer 2b are piled up, for example by overlapping three nonwoven fabrics. The cylindrical filter may be manufactured by arbitrarily changing the filtration characteristics (porosity and filtration opening size) and the permeation characteristics.

  Moreover, in the winding process of other embodiment, as shown, for example in FIG.4 (B), the nonwoven fabric 2a which forms an inner peripheral layer, and the nonwoven fabric 2b which forms an outer peripheral layer are comprised as one continuous nonwoven fabric. A non-woven fabric is wound on the mandrel 10 using the non-woven fabric 2c. In this case, a plurality of different types of nonwoven fabrics 2a and 2b can be wound around the mandrel 10 more efficiently. In yet another embodiment, a single continuous nonwoven fabric is formed from the first part that forms one end of the winding that forms the innermost circumferential layer 2i (see FIG. 6) of the cylindrical filter, from the first part of the cylindrical filter. Structures such as the material of the fibers forming the nonwoven fabric, the fiber diameter (average cross-sectional diameter), and the size of the filter opening up to the second part forming the other end of the winding end forming the outer peripheral layer 2o (see FIG. 6) You may comprise so that a characteristic may change continuously. Alternatively, one continuous nonwoven fabric may be a single nonwoven fabric having uniform mechanical properties.

  After winding the nonwoven fabric 2 around the mandrel 10, the mandrel 10 can be removed from the mandrel chuck 10a (see FIG. 2) of the winding device. In this Embodiment, the diameter of the outer periphery of the nonwoven fabric 2 after winding will be 19 mm. Winding is performed by sticking the ends of the wound nonwoven fabric 2 (both ends in the axial direction of the roll of the nonwoven fabric 2 after winding and the terminal portion of the nonwoven fabric 2) to the surfaces of the winding rollers 12a, 12b, 12c (see FIG. 3). When the finished (lower layer) nonwoven fabric 2 is lifted from the surface of the roll, the end of the nonwoven fabric 2 that has been lifted may be lightly pressed with a finger to remove the lift. In the subsequent first sintering step 102 (see FIG. 1), the nonwoven fabric 2 is placed in the sintering furnace so that the end portion of the wound nonwoven fabric 2 is positioned vertically upward, and sintering is performed. Also good. In this case, since the end portion can be sufficiently brought into contact with the lower layer nonwoven fabric 2 by the dead weight of the end portion in the winding direction of the nonwoven fabric 2, the non-woven fabric 2 is baked firmly by diffusion bonding the metal fibers in contact with each other. Can conclude. In the present embodiment, the diameter of the outer periphery of the nonwoven fabric 2 after the first sintering step 102 is reduced by 1 mm to 18 mm due to baking.

  With reference to FIG. 5, the compression process which concerns on this Embodiment is demonstrated in detail. In the first swaging step 103a (see FIG. 1) included in the first compression step 103 (see FIG. 1) shown in FIG. 5 (A), the first sintering step is performed at the rotation center of the rotating swaging jig 13. The nonwoven fabric 2 sintered at 102 (see FIG. 1) is inserted in the axial direction. The first pair of dies 13 a and the second pair of dies 13 b included in the swaging jig 13 are provided so as to be alternately reciprocated by a predetermined distance toward the rotation center of the swaging jig 13. For this reason, the sintered nonwoven fabric 2 inserted into the swaging jig 13 can be compressed by a predetermined amount along the thickness t (see FIG. 6) direction of the cylindrical filter to be manufactured. Further, the swaging jig 13 is provided so as to swage the sintered nonwoven fabric 2 by rotating the first and second die pairs 13a and 13b alternately and reciprocally while rotating. For this reason, the thickness t of the cylindrical filter manufactured by compressing the nonwoven fabric 2 can be manufactured as a uniform thickness t with no bias. In this Embodiment, the diameter of the outer periphery 2o of the nonwoven fabric 2 after the 1st swaging process 103a is compressed 3 mm, and becomes 15 mm.

  Here, the reciprocating motion of the swaging jig 13 is performed as follows. First, the first pair of dies 13 a is struck onto the nonwoven fabric 2 wound around the mandrel 10. In that state, that is, in a state where the first pair of dies 13 a holds the roll of the nonwoven fabric 2, the second pair of dies 13 b is separated from the layer of the nonwoven fabric 2 and then the nonwoven fabric 2 wound around the mandrel 10. Nailed to. Next, the first pair of dies 13 a is separated from the layer of the nonwoven fabric 2 while the second pair of dies 13 b holds the roll of the nonwoven fabric 2. In this way, the reciprocating motion is repeated.

  In the first release step 103b (see FIG. 1) of the first compression step 103 (see FIG. 1) shown in FIG. 5 (B), the sintered and compressed nonwoven fabric 2 is released from the mandrel 10. Remove. For example, in the first release step 103b, the mandrel 10 and the nonwoven fabric 2 (release sheet material 11 () are used by using a release tool 14 having a through hole 14a that fits with a small gap from the outer diameter of the mandrel 10. (See FIG. 2)) and release the mold by applying a shearing force. In the present embodiment, the nonwoven fabric 2 (release sheet material 11) and the mandrel are pressed by pressing the upper end portion of the mandrel 10 with, for example, a press press machine (not shown) while the nonwoven fabric 2 is supported by the release jig 14. 10 is released by applying a shearing force to the contact surface. Alternatively, in another embodiment, the mandrel 10 may be released by applying an intermittent hit by hitting the mandrel 10 with a resin hammer (not shown). In this case, a cylindrical filter can be manufactured more easily.

  In the present embodiment, the nonwoven fabric 2 and the mandrel 10 are sintered (diffusion bonding) because the nonwoven fabric 2 is wound on the mandrel 10 via alumina paper which is a release sheet material 11 (see FIG. 2). ) And will not stick. Alumina paper is brittle and easy to release because the organic matter that binds the alumina fibers is thermally decomposed in the first sintering step 102 (see FIG. 1). Moreover, since the wire diameter (average cross-sectional diameter) da of the metal fibers forming the inner periphery 2i (see FIG. 6) of the nonwoven fabric is provided at a relatively large wire diameter, the contact area of the nonwoven fabric 2 on the inner periphery 2i is large. It is small and is provided so that the frictional force generated on the contact surface at the time of mold release can be reduced. Further, since the nonwoven fabric 2 (release sheet material 11) is swaged and plastically deformed in the first swaging step 103a (see FIG. 1), the mandrel is formed on the inner circumference 2i (release sheet material 11) of the nonwoven fabric. The portion in contact with 10 is deformed and moved so that it can be easily released. For this reason, the nonwoven fabric 2 can be easily released from the mandrel 10 and removed. Moreover, after releasing the nonwoven fabric 2 from the mandrel 10, the alumina paper 11 which is a release material remaining on the inner periphery 2i of the nonwoven fabric can be easily removed by air blowing and wiping.

  In the tubular filter manufacturing method 100 (see FIG. 1) according to the present embodiment, as described above, after the first release step 103b (see FIG. 1), the second heating is performed again at 750 degrees Celsius for 1 hour. And a second sintering step 201 (see FIG. 1) having a pre-heating step 201b and a second bonding sintering step 201c heated at 1170 degrees Celsius for 2 hours. In addition, as described above, the second sintering step 201 includes the second cooling step 201d that is air-cooled with a blower fan for 40 minutes and then gradually cooled, and nitrogen gas is injected into the sealed container to completely discharge the hydrogen gas. The second replacement step 201e. By passing through the 2nd sintering process 201, the nonwoven fabric 2 is sintered more firmly. The diameter of the outer periphery 2o of the nonwoven fabric after the second sintering step 201 is reduced by 0.5 mm to 14.5 mm due to baking. As described above, the shrinkage in the second sintering step 201 is reduced more than the shrinkage in the first sintering step 102 (see FIG. 1) by reducing the bonding sintering temperature by 20 degrees Celsius. .

  In addition, as described above, the cylindrical filter manufacturing method 100 according to the present embodiment 100 (see FIG. 1) is followed by the second swaging step 202a (FIG. 1) after the second sintering step 201 (see FIG. 1). And a second compression step 202 (see FIG. 1) having a second release step 202b (see FIG. 1). As described above, in the second swaging step 202a, in order to compress the nonwoven fabric 2 directly onto the mandrel 10 without the release sheet material 11 (see FIG. 2), the inner periphery 2i of the nonwoven fabric (see FIG. 6). The cylindrical filter can be manufactured with high accuracy by completely matching the shape and size of the filter with the outer periphery of the mandrel 10. In addition, the second compression step 202 can accurately manufacture a cylindrical filter having an arbitrary porosity. Swaging in the second swaging step 202a is performed using two pairs of dies 13a and 13b having an inner diameter different from that in the first swaging step 103a. The diameter of the outer periphery 2o of the non-woven fabric after the second swaging step 202a is reduced by 1.8 mm to be manufactured as 12.7 mm which is the size of the outer diameter of the finished cylindrical filter. The porosity is 27.12% and is manufactured with high accuracy.

  In the second release step 202b (see FIG. 1) following the second swaging step 202a (see FIG. 1), the nonwoven fabric 2 can be easily released from the mandrel 10 and removed. This is because, in the second sintering step 201 (see FIG. 1), the mandrel 10 of the present embodiment is made of zirconia, and the nonwoven fabric 2 is made of stainless steel, so that it is difficult to perform diffusion bonding with each other. This is because it is once sintered and swaged. Further, in the second swaging step 202a, when the nonwoven fabric 2 is further plastically deformed, a certain shearing force can be applied to the contact surface between the nonwoven fabric 2 and the mandrel 10. In another embodiment, the second mold release step 202b uses a difference in thermal expansion between the mandrel and the non-woven fabric, which are made of different materials, and heats them. A heat separation step (not shown) for applying a shearing force to the surface and separating both in the radial direction may be further included. In particular, as described above, the difference in coefficient of linear expansion between the non-woven metal fiber and the mandrel material may be used. In this case, for example, the mandrel and the nonwoven fabric are heated together by heating at a temperature in the range of 100 degrees Celsius to 300 degrees Celsius, preferably in the range of 150 degrees Celsius to 250 degrees Celsius, in this embodiment, 200 degrees Celsius. Using the difference, the mandrel and the nonwoven fabric can be separated and released.

  Finally, both end portions (both ends 35 mm) of the axial length (manufacturing length 270 mm) of the nonwoven fabric after release according to the present embodiment are cut off to obtain an axial length 200 mm when completed. In this case, since only the central part with the highest manufacturing reliability among the manufactured nonwoven fabrics can be formed into a completed cylindrical filter, a high-quality cylindrical filter can be manufactured. In other embodiments, the length in the axial direction at the time of manufacturing the non-woven fabric may be made to coincide with the length in the axial direction of the cylindrical filter at the time of completion from the beginning. In this case, a cylindrical filter can be manufactured more easily. As described above, according to the cylindrical filter manufacturing method of the present embodiment, a high-performance cylindrical filter can be easily manufactured.

  With reference to FIG. 6, the cylindrical filter which concerns on the 2nd Embodiment of this invention is demonstrated. The cylindrical filter 1 is provided by the cylindrical filter manufacturing method 100 (see FIG. 1) of the first embodiment described above. As described above, the cylindrical filter 1 is a cylindrical filter 1 that is seamlessly formed into a cylindrical shape with a non-woven fabric 2 of metal fibers, and an inner peripheral layer 2a that forms an inner periphery 2i of the cylindrical filter (see FIG. 2). ) And an outer peripheral layer 2b (see FIG. 2) that forms the outer periphery 2o of the cylindrical filter, and is an outer peripheral layer formed of metal fibers having a diameter db different from the diameter da of the non-woven fabric metal fibers that form the inner peripheral layer 2a 2b, and the nonwoven fabric 2 is provided as a cylindrical filter compressed in the thickness t direction.

  For this reason, the cylindrical filter 1 can be provided as a highly reliable cylindrical filter that does not have an internal structural defect due to a seam. Further, the cylindrical filter 1 can be provided as an excellent cylindrical filter having an inclined internal structure and porosity corresponding to a change in rigidity of the nonwoven fabric in the thickness t direction and having desired filtration characteristics. Further, the opening direction (the normal direction of the opening surface) of the filtration opening of the nonwoven fabric 2 compressed with the cylindrical filter 1 is oriented so as to face the thickness t direction, and the permeation resistance (pressure loss) during filtration is small. It can be provided as a high performance cylindrical filter.

When a bubble point test was performed on the cylindrical filter 1 of the present embodiment, a high initial bubble point value (according to ISO regulations) of 2.5 kPa to 25 kPa and a high burst bubble point value of 3 kPa to 36 kPa (in this industry) It was possible to confirm the excellent performance of having (according to a standard measurement method). Based on this measurement value, using the filtration accuracy calculation formula of Bekaert, a representative manufacturer of metal fiber nonwoven fabrics, the absolute filtration accuracy (maximum filtration opening size) of the cylindrical filter 1 is It can be estimated that the average pore diameter (average filter opening size) is 1.03 μm to 12.3 μm.
Absolute filtration accuracy = 37 kPa / initial bubble point value Average pore size = 37 kPa / burst bubble point value

In the cylindrical filter 1 of the present embodiment, the inner circumferential layer 2a (see FIG. 2) is wound around 7.5 turns (roll length 300 mm), and the outer circumference layer 2b (see FIG. 2) is wound around 22.6 turns (see FIG. 2). Roll length 900 mm), basis weight 150 g / m ² , volume 6.1903 cm ³ (inner diameter 11.04 mm, outer diameter 12.7 mm, axial length 200 mm), weight 36 g, porosity 27.12% It was. By providing palladium or palladium alloy plating 3 on the surface of the inner periphery 2i or outer periphery 2o of the cylindrical filter 1 (particularly the surface on the smaller side of the fiber system), a hydrogen permeation filter for fuel cells having excellent performance is provided. Can do. In other embodiments, for example, the porosity is changed by changing the number of turns of the outer peripheral layer 2b to 7.5 (300 mm), 15 (600 mm), and 30.1 (1200 mm), respectively. May be provided with different cylindrical filters of 63.56% (weight 18 g), 45.34% (weight 27 g), and 8.9% (weight 45 g). Similarly, a hydrogen permeation filter for fuel cells having excellent performance may be provided by applying palladium or palladium alloy plating 3 on the inner peripheral surface 2i or outer peripheral surface 2o of these cylindrical filters.

DESCRIPTION OF SYMBOLS 1 Tubular filter 2 Metal fiber nonwoven fabric 2a Inner circumference layer 2b Outer circumference layer 2c One continuous nonwoven fabric 2i Inner circumference 2o Outer circumference 3 Palladium or palladium alloy plating layer 10 Mandrel 10a Mandrel chuck 11 Release sheet material (alumina paper)
12a First winding roller 12b Second winding roller 12c Third winding roller 13 Swaging jig 13a First pair of dies 13b Second pair of dies 14 Release jig 14a Through hole 20 Winding device

Claims (9)

A winding step of winding a metal fiber nonwoven fabric into a plurality of layers to form a cylinder;
A sintering step of sintering the wound nonwoven fabric;
A compression step of compressing the sintered nonwoven fabric;
Manufacturing method of cylindrical filter.   The said winding process is a manufacturing method of the cylindrical filter of Claim 1 including the process of winding the said nonwoven fabric on a mandrel. The compressing step includes a step of swaging the nonwoven fabric between the mandrel and a swaging jig;
And a step of releasing the swung nonwoven fabric from the mandrel;
The manufacturing method of the cylindrical filter of Claim 2.   The diameter of the metal fiber of the nonwoven fabric that forms the inner peripheral layer of the plurality of layers is configured to be different from the diameter of the metal fiber of the nonwoven fabric that forms the outer peripheral layer of the plurality of layers. The manufacturing method of the cylindrical filter of any one of Claim 1 thru | or 3.   The manufacturing method of the cylindrical filter of Claim 4 using the nonwoven fabric comprised in the said winding process as the nonwoven fabric which forms the said outer peripheral layer and the nonwoven fabric which forms the said outer peripheral layer as one continuous nonwoven fabric. .   The method for manufacturing a cylindrical filter according to claim 4, wherein in the winding step, a plurality of nonwoven fabrics composed of metal fibers having different diameters are overlapped and wound.   The manufacturing method of the cylindrical filter of any one of Claim 1 thru | or 6 provided with the process of plating palladium or a palladium alloy on the inner surface or outer surface of the said cylinder after the said compression process. A cylindrical filter seamlessly formed into a cylindrical shape from a nonwoven fabric of metal fibers;
An inner circumferential layer forming an inner circumference of the cylindrical filter;
An outer peripheral layer forming an outer periphery of the cylindrical filter, the outer peripheral layer including metal fibers having a diameter different from the diameter of the metal fibers of the nonwoven fabric forming the inner peripheral layer;
The nonwoven was compressed in the thickness direction;
Tubular filter.   The cylindrical filter according to claim 8, comprising a palladium or palladium alloy layer formed on a surface of the inner peripheral layer or the outer peripheral layer.

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