JP2859846B2 - Metal filter and method for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant metal filter suitable as a high-temperature gas filter, and more particularly to a method of manufacturing a metal filter having flexibility in a shape of a molded product and hardly deforming at a relatively low cost. About.

[0002]

2. Description of the Related Art Sintered metal materials are produced by press-forming and sintering metal raw material powders, and can be applied to filters, bearings, electrodes and the like by utilizing the porosity. Sintered metal filters have various materials ranging from bronze to stainless steel and noble metals, and are used not only for filtration / separation but also for diffusion and buffering.

[0003] The sintered metal filter can contain a large amount of a filter substance without lowering the air permeability, as compared with a filter made of a resin, a ceramic, or the like. It can be used repeatedly and has excellent mechanical properties such as heat resistance, thermal shock resistance and strength, and is suitable as a filter for a combustion furnace gas.

[0004]

SUMMARY OF THE INVENTION A sintered metal filter is
Although having the above-mentioned advantages, it is very expensive as a whole since it uses metal powder which is considerably more expensive than the raw material for dissolving the metal and requires a precise and expensive mold. In the sintered metal filter, the powder compact is heated to a high temperature below the melting point during the sintering process to form a solid by bonding, so that the molded product does not lose its shape, but its shape is flexible. In addition, since the dimensional tolerance between the filter mounting member and the filter mounting member is extremely small, it is necessary to increase the dimensional accuracy of the mounting member.

The present invention has been proposed as a filter material that replaces a sintered metal filter in which the above-described essential problems are inherent, and has excellent mechanical properties close to that of a sintered metal filter. Moreover, it is an object of the present invention to provide a metal filter which has flexibility in the shape of a molded product and is hardly deformed. It is another object of the present invention to provide a method for manufacturing a metal filter formed into a predetermined shape at a relatively low cost.

[0006]

In order to achieve the above object, a metal filter 1 according to the present invention has a cylindrical shape as shown in FIG. 1 and has an inner cylindrical wire mesh 2 and a metal fiber felt. The filter comprises a filter body 3 in which a sheet is wound around an inner cylindrical wire net to a predetermined thickness, and an outer cylindrical wire mesh 4. Although the shape of the metal filter 1 is typically a cylinder, a cylinder having a shape of a triangle or more or a cylinder having an irregular shape such as an ellipse can be manufactured.

The material of the filter body 3 may be any metal fiber that can be plastically deformed, and examples thereof include stainless steel, iron, copper, aluminum, silver, bronze, and brass, and may be a noble metal. In order to manufacture the felt sheet 7 (FIG. 3) for the filter body 3, for example, the wrapping of the metal fiber is oriented in the thickness direction by needle punching, and further pressed as needed.
Fine felting by water jet treatment.

[0008] The inner and outer cylindrical wire meshes 2, 4 are formed by welding a vertical overlapping portion after bending a sheet-like body into a circular shape,
This welding may be either continuous welding or spot welding at appropriate intervals. As the wire meshes 2 and 4, fine meshes are used so as not to affect the air permeability and pressure loss of the metal filter 1, and for example, a stainless steel net having a wire diameter of about 0.2 mm is preferable.

In the method for manufacturing a metal filter according to the present invention, first, in FIG.
And the overlapping portion 10 is fixed. This fixing means is generally welded or brazed, but may be fixed by sewing or mounting hardware. Next, as shown in FIG. 4, a thin metal fiber sheet 7 (FIG. 3) obtained by needle punching is wound around the tubular wire mesh 2 several times and laminated to a predetermined thickness. Further, as shown in FIG. It is wound into a shape and the overlapping portion 12 is fixed.

The obtained tubular filter material is impregnated with a heat-resistant resin liquid by dipping, spraying, coating or the like. The resin liquid used is generally a heat-resistant acrylic resin such as a silica acrylic resin or an inorganic resin such as a silicon oxide resin or a water glass resin. The resin-impregnated filter material needs to be heated at a relatively high temperature for a long time because the resin solvent is vaporized and evaporated to be cured by heating.

In the method of the present invention, the metal filter to be manufactured can be formed not only in a cylindrical body but also in a dish-shaped body or a bowl-shaped body, for example. In this case, although not shown, a flat or preformed wire mesh is placed on a predetermined form, a metal fiber sheet is laminated, and a flat or preformed wire mesh is placed on the upper side. The obtained filter material may be impregnated with a heat-resistant resin liquid, and may be press-formed into a predetermined shape when the filter material is cured by applying pressure and heat. If necessary, the upper and lower metal meshes may be welded to each other so as not to be separated, or a separate metal fitting may be attached.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A metal filter 1 shown in FIG. 1 is, for example, a cylindrical body having an outer diameter of 70 mm and a thickness of 5 mm. The metal filter 1 has an inner cylindrical wire mesh 2 welded with a vertical overlapping portion 10, a filter body 3 in which a thin felt sheet of metal fibers is wound around the inner cylindrical wire mesh 2 to a predetermined thickness, and The overlapped portion 12 is constituted by a welded outer cylindrical wire mesh 4. Wire meshes 2 and 4 are about 25 mesh and fine
Moreover, since the wire diameter is 0.2 mm or less, the influence on the air permeability and pressure loss of the metal filter 1 is small.

As a material of the filter body 3, for example,
A stainless steel fiber having a wire diameter of 5 to 30 μm is used.
In this case, the wire diameter 2 obtained by drawing stainless steel
A mat having a diameter of 5 to 30 μm or a wrap having a wire diameter of 5 to 13 μm is obtained by carding a tow obtained by concentrating and drawing the wire, and their thickness is usually about 10 to 30 mm.

The mat or wrap is thinned by needle punching two or three times to form a sheet having a thickness of 1.5 to 3 mm. Subsequently, the fiber is pressed once or twice at a normal temperature at a pressure of 5 to 100 kg / cm ² , and particularly at a high rigidity, three times at a pressure of 5 to 100 kg / cm ² to obtain a thickness of 0.4.
To 0.7 mm. Thin felt sheet 7
Is wound around the cylindrical wire mesh 2 5 to 10 times to determine a predetermined thickness.

The obtained cylindrical filter material is impregnated with a silica acrylic resin solution or the like by dipping, and then pressure is applied to adjust the impregnation amount. The amount of impregnation of this resin may be 1 to 3% by weight owf if it is formed flexibly only for shape retention, and up to about 10% by weight owf if a predetermined hardness is imparted to the filter. The resin-impregnated filter material needs to be heated at least at about 150 ° C. for at least 30 minutes in order to promote the vaporization and evaporation of the resin solvent and the curing of the resin, and cut to a predetermined length when the curing of the resin is completed. .

In the metal filter 1, the density and thickness of the filter main body may be adjusted according to the size of impurities in the high-temperature gas to be filtered.
100 μm impurities, finer felt
Even impurities of about 2 μm can be collected by filtration. Metal filter 1
Can be applied as a filter for an inflator of an automobile airbag, a filter for a high-temperature strainer, a filter for a combustion furnace gas, and the like.

[0017]

Next, the present invention will be described based on embodiments. Example 1 In order to manufacture the metal filter 1 shown in FIG. 1, as shown in FIG.
m stainless steel net 2 is wound around a cylindrical core material 6 having a diameter of 60 mm. When the net 2 is completely wound, the net 2 becomes circular and both ends are overlapped by about 5 mm. Therefore, the overlapped portions 10 are spot-welded at appropriate intervals in the vertical direction. The pressure loss of the net 2 is about 10 mmH ₂ O / l · sec.

A stainless steel fiber sheet 7 (FIG. 3) having a thickness of 0.6 mm is wound around the tubular net 2 five times. The fiber sheet 7 has a wire diameter of about 25 μm and a fiber length of 2
0-100mm stainless steel fiber (SUS-3
16L). This stainless steel fiber has a thickness of about 20 obtained by drawing stainless steel.
mm a lap, needle punching in the lap (needle number 30 present / cm ²⁾ by performing three times to reduce the thickness 2 mm, then the thickness and pressed at room temperature 2 times at a pressure 5 to 100 kg / cm ² It is reduced to 0.6 mm, and is further cut and used as a fiber sheet 7 in a 160 mm wide band.

On the filter body 3 wound in a cylindrical shape,
A stainless steel net 4 having a width of 160 mm and the same 24 mesh as described above is wound. When the net 4 is completely wound, it becomes circular and both ends are polymerized by about 5 mm.
The overlapping portion 12 is spot-welded at appropriate intervals in the vertical direction. The obtained cylindrical filter material has an inner diameter of 60 mm, an outer diameter of 70 mm, and a wall thickness of 5 mm.

The cylindrical filter material is impregnated with a silica acrylic resin solution by dipping, and then a pressure of 20 kg / cm ² is applied to adjust the resin impregnation amount to about 5% by weight owf. Next, the cylindrical core material 6 is pulled out, and the resin-impregnated filter material is placed in an oven and heated. The heating temperature and time are 80 ° C. for 30 minutes and 150 ° C.
For 30 minutes, thereby evaporating and evaporating the resin solvent and curing the resin. When the curing of the resin is completed, the resin is cut to a length of 150 mm with a diamond cutter.

When the obtained metal filter 1 is used for a high-temperature strainer, it is possible to filter out impurities of 50 to 100 μm. The metal filter 1 has flexibility in the shape of the molded product, is hardly deformed, and can be installed even if there is some dimensional error with the filter mounting member.

Embodiment 2 In order to manufacture the metal filter 1, as shown in FIG.
A stainless steel net 2 having a wire diameter of 0.2 mm and 24 mesh is wound around a cylindrical core material 6 having a diameter of 30 mm. The net 2 is completely wound in a circular shape, and the overlapped portion 10 is spot-welded at appropriate intervals in the longitudinal direction.

A 0.7 mm thick stainless steel fiber sheet 7 (FIG. 3) is wound on the cylindrical net 2 six times. The fiber sheet 7 is manufactured from stainless steel fibers having a wire diameter of 5 to 13 μm and a fiber length of 20 to 100 mm. This stainless steel fiber has a wire diameter of 5-1 which is obtained by focusing and drawing stainless steel material and then carding.
A wrap having a thickness of 3 μm and a thickness of 30 mm. The wrap was subjected to needle punching (30 needles / cm ² ) three times to reduce the thickness to 3 mm.
Pressing at room temperature three times at cm ² reduces the thickness to 0.7.
mm.

On the filter body 3 wound in a cylindrical shape,
24 mesh stainless steel net 4 as above
Is wound in a circle. When the net 4 is completely wound, the net 4 becomes circular, and the overlapped portion 12 is spot-welded at appropriate intervals in the vertical direction. The obtained cylindrical filter material has an inner diameter of 3
0 mm, outer diameter 40 mm, wall thickness 5 mm.

The cylindrical filter material is impregnated with a silica acrylic resin solution by dipping, and then a pressure of 30 kg / cm ² is applied to adjust the resin impregnation amount to about 3% by weight owf. Next, the cylindrical core material 6 is pulled out, and the resin-impregnated filter material is placed in an oven and heated. The heating temperature and time are 80 ° C. for 30 minutes and 150 ° C.
For 30 minutes, thereby curing the resin.

When the obtained metal filter 1 is used as a filter for a combustion furnace gas, it is possible to filter soot up to about 1 to 2 μm. The metal filter 1 has flexibility in the shape of the molded product, and can be installed even if there is some dimensional error with the filter mounting member.

Example 3 In order to manufacture a dish-shaped metal filter having a curved surface,
A stainless steel net preformed in a shallow dish shape is placed on a predetermined formwork. Next, five metal fiber sheets used in Example 1 are laminated, and a net preformed in the same manner as described above is placed on the upper side. Separate fixing brackets are attached so that the upper and lower nets do not separate.

The obtained shallow dish-shaped filter material is impregnated with a silica acrylic resin solution by dipping, and then a pressure of 30 kg / cm ² is applied to reduce the resin impregnation amount to about 5%.
Adjust to wt% owf. Remove the fixing bracket,
When the filter material is cured by heating at 80 ° C. and then at 150 ° C. for 1 hour, the filter material is pressed into a predetermined dish shape. The obtained dish-shaped filter material has a thickness of 5 mm.
And cut to a diameter of 60 mm.

The obtained dish-shaped metal filter can be attached to a vent or an exhaust hole in various furnaces. This metal filter has versatility in the shape of the molded product, and can be installed even if there is some dimensional error with respect to vent holes and exhaust holes.

[0030]

Although the metal filter of the present invention is much less expensive than known sintered metal filters, it has excellent mechanical properties comparable to sintered metal filters. This metal filter is relatively flexible in the shape of the molded product, and it is hard to lose its shape, so it can be installed even if there is some dimensional error with the filter mounting member, reducing the occurrence of defective products due to dimensional error. Is possible.

In the metal filter of the present invention, the density and thickness of the filter main body can be adjusted according to the size of impurities in the high-temperature gas to be filtered. If the felt is fine, impurities of about 1 to 2 μm can be collected by filtration. This metal filter can be applied in various fields as a filter for an inflator of an automobile airbag, a filter for a high-temperature strainer, a filter for a combustion furnace gas, and the like.

According to the method of the present invention, a metal filter that can be formed into a desired shape can be easily manufactured. Further, the method of the present invention has an advantage that a metal filter can be manufactured at a low cost since inexpensive raw materials are used, and the number of manufacturing steps is relatively small and simple.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view of a metal filter according to the present invention.

FIG. 2 is a schematic perspective view showing a state in which an inner cylindrical wire mesh is wound around a cylindrical core material.

FIG. 3 is a schematic perspective view of a metal fiber sheet used in the present invention.

FIG. 4 is a horizontal sectional view showing a next manufacturing process of the present invention.

FIG. 5 is a horizontal sectional view showing a further next manufacturing step of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal filter 2 Inner cylindrical wire mesh 3 Filter body 4 Outer cylindrical wire mesh 6 Cylindrical core material 7 Metal fiber sheet

Claims (4)

(57) [Claims] 1. A filter in which a longitudinally overlapped portion is welded to an inner cylindrical wire mesh, and a felt sheet of metal fiber is wound around the inner cylindrical wire mesh to a predetermined thickness and impregnated with a heat-resistant resin and dried. A cylindrical body that consists of a main body and an outer cylindrical wire mesh that welds a vertical overlapping portion, and adjusts the density and thickness of the filter main body according to the size of impurities in the high-temperature gas to be filtered. Metal filter. 2. A thin felt sheet is formed from a wrapping of the metal fiber by needle punching and pressing, using a plastically deformable metal fiber such as stainless steel, iron, copper, aluminum, silver, bronze or the like as a material of the filter body. The metal filter according to claim 1, wherein 3. A flat wire mesh is wound around a cylindrical core material in a circular shape, the overlapping portion is fixed, and then a needle-punched thin metal fiber sheet is wound around a tubular wire mesh and laminated to a predetermined thickness. After winding a flat wire mesh in a circular shape and fixing the overlapping portion, the obtained tubular filter material is impregnated with a heat-resistant resin liquid, and the filter material is dried by heating and then cut into a predetermined length. Manufacturing method of metal filter. 4. A flat or preformed wire mesh is placed on a formwork, a needle-punched thin metal fiber sheet is laminated to a predetermined thickness, and a flat or preformed wire mesh is further placed on the upper side. A method of manufacturing a metal filter in which a filter material obtained is impregnated with a heat-resistant resin liquid after being placed, and is formed into a predetermined shape when the filter material is cured by applying pressure and heat.