JP3346991B2 - 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 metal filter and a method of manufacturing the same, and more particularly, to a metal filter formed by sintering metal particles into a cylindrical shape and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a metal filter has been used in which the entire wall thickness is formed by a filtration layer having a uniform distribution of pore diameters over the entire area. Then, in controlling the diameter distribution of the perforated holes in the production, adjustment of the particle size distribution of the metal particles to be sintered and the degree of sintering (that is, the degree of baking) are performed.
Had been adjusted.

[0003]

However, the degree of sintering depends on the sintering temperature at which the metal filter to be sintered is heated and the holding time at the sintering temperature. When sintering the sintering body, it is difficult to accurately grasp the temperature of the individual sintering body, so that the adjustment is also difficult, and as a result, the sintering degree of the metal filter is adjusted. Is extremely difficult, and the distribution of the through-hole diameters is affected by the sintering degree. Therefore, there is a problem that the yield is extremely deteriorated if the accuracy of the through-hole diameter is to be improved. That is, when the preformed body of metal particles is maintained at a high temperature for sintering, the gap between the metal particles gradually decreases with the progress of sintering between the metal particles, for example, a metal filter having a fine pore diameter. When sintering metal particles having a small particle size in order to form a sintered body, excessive sintering reduces the diameter of the permeation hole, or causes the permeation hole to be crushed, resulting in a decrease in the air permeability, and a decrease in the air permeability. If the sintering temperature is lowered for maintenance or the sintering time is shortened to lower the sintering degree, there is also a problem that insufficient sintering leads to insufficient strength of the metal filter. Therefore,
In order to compensate for the insufficient strength, if the thickness of the filtration layer formed of metal particles having a small particle diameter is increased in order to impart sufficient strength to the metal filter, the ventilation resistance increases, and the ventilation pressure loss is appropriately maintained. Therefore, there is a problem that the filtration area must be increased. The present invention solves the above-mentioned problems, and can control the distribution of the transmission hole diameter while maintaining the strength as a sintered body, and can reduce the size of equipment such as dust removal equipment. An object of the present invention is to provide a filter and a manufacturing method thereof.

[0004]

[Operation and effect of first characteristic configuration]

According to the first characteristic configuration, the diameter of the permeation hole (determining the minimum inhibitor particle size) of the filtration section can be easily controlled, and at the same time, the filter has sufficient strength and can reduce the ventilation pressure loss without increasing the filtration area. A metal filter that can be kept low can be easily manufactured.
Further, since it has heat resistance, clogging due to combustible dust can be removed by burning inside by heating. In other words, since the metal filter is formed by sintering the filtration part and the support part integrally on the front and back, the filtration part is formed of small-diameter filtration part forming material particles corresponding to the diameter of the transmission hole to control the diameter of the transmission hole. In order to easily maintain the strength of the supporting portion, the supporting portion is formed of metal particles having a larger diameter than the filtering portion forming material particles corresponding to the transmitting hole diameter larger than the transmitting hole diameter of the filtering portion. Thus, sufficient strength can be imparted to the metal filter while lowering the ventilation resistance of the support portion. For example, if a material having a high sintering temperature is used for the filtration portion forming material particles and sintering is performed without increasing the sintering degree, the diameter of the permeation hole of the filtration portion can be easily controlled, and the support portion forming metal can be easily formed. If a sufficient sintering degree is maintained by using a material having a lower sintering temperature as compared to the material of the filtration part forming material particles,
The strength of the supporting portion can be sufficiently ensured, and at the same time, the filtering portion can be sufficiently supported. In particular, the filtration unit and the support unit are integrally formed by sintering under isostatic pressure, and when sintering under high pressure, it sinters sufficiently at a relatively low temperature. The strength of the metal filter can be sufficiently maintained. Therefore,
Since the thickness of the filtration section can be reduced and the ventilation resistance of the support section can be kept low, it is possible to keep the ventilation pressure loss of the metal filter low without increasing the filtration area. Therefore, it is possible to reduce the size of equipment using a metal filter, such as dust removal equipment. Also, the support part forming gold
Genus particles, 3 times or less of the average particle diameter of the filtration part forming material particles
By having an average particle diameter of
Similar to the fourth feature configuration, different roles are assigned to the filtration unit and the support unit.
While maintaining low ventilation pressure loss,
Integrated with high filtration accuracy and high strength
It is possible to easily manufacture a metal filter that has been manufactured.
In other words, the average particle diameter of three times or less the average particle diameter
If the supporting part is composed of metal particles, the filtering part forming particles are supported
While preventing it from entering between the part forming metal particles.
It is possible to maintain the strength of the holding portion suitably. As a result, it is possible to control the transmission hole diameter distribution while maintaining the strength of the metal filter, thereby facilitating the manufacture of a metal filter capable of downsizing equipment. Also, increase the strength of the metal filter.
Increase the filtration area of the metal filter while maintaining an appropriate level
Without this, the increase in the ventilation pressure loss can be suppressed. [Second characteristic configuration and operation and effect] The second characteristic configuration of the metal filter of the present invention is described in claim 2.
As described in the above, the sintering is performed integrally in a state where a mesh-like metal body having an opening of not more than the minimum particle diameter of the filtration part forming material particles is interposed between the filtration part and the support part in the first characteristic configuration. This is because the formed body before sintering is easy to handle even if the filtration part is formed thin, and a metal filter with low airflow resistance can be manufactured. That is, by interposing a mesh-like metal body between the filtration unit and the support unit, mixing of the filtration-section-forming material particles into the support-section-forming metal particles is prevented by the mesh-like metal body. And the support portion can be easily separated into layers. In particular, if the mesh metal body is formed of a wire mesh, a gap can be ensured by the weave of the wire mesh, so that the air permeability is further improved. In addition, after the preforming before sintering, the reticulated metal body functions as a shape retainer for the preformed body, so that the presintered body is easily handled. If the particle size of the filtration unit is adjusted to a predetermined minimum blocking particle size and the support unit is set to a particle size that can maintain sufficient air permeability after sintering, the filtration supported by the mesh metal body Even if the portion is thin, it can be formed by sintering, and a metal filter with low airflow resistance can be manufactured. Further, by selecting the material of the net-like metal body, it becomes easy to form the support portion and the filtration portion with metal particles made of different materials. In this case, if the reticulated metal body is formed of a material having good bonding properties to both the filtering part and the support part, the integration of the two parts is further strengthened.
That is, the filtering section is formed of metal particles made of a material whose transmission hole diameter can be easily controlled, and metal particles made of a material having good sinterability can be easily used for the support section. As a result, it is possible to control the distribution of the permeation pores while maintaining the strength of the metal filter suitably, and it becomes easy to manufacture a metal filter capable of maintaining a low ventilation pressure loss without increasing the filtration area. [Third characteristic configuration and operation and effect] In the third characteristic configuration of the metal filter according to the present invention, as described in claim 3, the filtering unit in the first or second characteristic configuration is provided with a distribution width of a transmission hole diameter. The ratio to the average transmission pore size,
That is, in the volume-based cumulative distribution curve of the through-hole diameter, the through-hole diameter D ₉₅ at the cumulative frequency of ₉₅ % and the air-through hole diameter D at the cumulative frequency of 5%.
_The ratio of the difference from ₅ to the permeation pore diameter D ₅₀ (corresponding to the average permeation pore diameter) at a cumulative frequency of 50% (hereinafter referred to as the permeation pore diameter distribution ratio) is (D ₉₅ −D ₅ ) / D ₅₀ ≦ 1. In this respect, it is possible to prevent the ventilation resistance from increasing more than necessary even if the minimum blocking particle size is reduced. In other words, it is possible to narrow the distribution of the diameters of the permeation holes in the filtration unit, thereby preventing the formation of permeation holes having a permeation hole diameter smaller than necessary with respect to the minimum blocking particle diameter.
That is, the minimum blocking particle diameter in the filtration section is the cumulative frequency 1
By preventing formation of a transmission hole having a small diameter, which corresponds to a transmission hole diameter of 00%, it is possible to prevent the airflow resistance from being increased while exhibiting the characteristics of the filter. The distribution ratio of the permeation pore diameters is the particle size R ₉₅ of the cumulative frequency of 95% and the particle size R ₅ of the cumulative frequency of 5% in the volume-based cumulative distribution curve of the particles to be sintered obtained in the same manner as described above. difference, relative cumulative frequency of 50% particle size R ₅₀ (corresponding to the average particle diameter.), shows a strong correlation particle size distribution ratio expressed by _{(R 95 -R 5) / R} 50, By controlling the average particle size and the particle size distribution ratio, the distribution of the permeation pore size can be easily controlled. This is based on the inventors' new knowledge. In addition, it is preferable that the transmission hole diameter distribution ratio is suppressed to 1 or less.
It is preferably within the range of 1. As a result, the filtration accuracy can be increased while maintaining the ventilation pressure loss of the metal filter low more easily. [Fourth characteristic configuration and operation and effect] According to a fourth characteristic configuration of the metal filter of the present invention, as described in claim 4, the mesh of the mesh-like metal body in the second or third characteristic configuration is removed by the filtration. This is at least 30% of the average particle diameter of the part forming material particles. In this case, the ventilation resistance of the metal filter does not increase even if the mesh metal body is interposed. That is, the diameter of the permeation hole formed in the sintered body is usually 30% or less of the average particle diameter of the particles to be sintered. If it does above, it will not become smaller than the diameter of the permeation hole of the said filtration part, and the air permeability will be better. As a result, a metal filter that can maintain low ventilation pressure loss is obtained. Fifth characterizing feature and advantages] The fifth characterizing feature of the metal filter of the present invention, as described in claim 5, the filtration section-forming material particles in any of the first characterizing feature to the fourth characterizing feature And the supporting portion forming metal particles are both made of a high-temperature corrosion-resistant metal. By doing so, it is possible to easily manufacture a metal filter that can also be used for filtering hot corrosive raw gas. Now you can. That is, by forming the metal filter with a high-temperature corrosion-resistant metal such as Inconel or Hastelloy, for example, a filter having sufficient high-temperature corrosion resistance can be obtained. Incidentally, sintering of Inconel, Hastelloy, and the like is considered to be extremely difficult, but sintering under isostatic pressure enables sintering of such a metal filter. As a result, for example, it was possible to obtain a metal filter capable of removing high-temperature exhaust gas from a waste incineration furnace without cooling it without cooling.

[0005] Sixth, characterized Configuration of producing how the metal filter of the present invention, as described in claim 6, to form a filtered portion formed particle layer in the filtration section-forming material particles in a cylindrical mold on the inner surface A mesh metal body having an aperture of 30% or more of the average particle diameter of the filtration part forming material particles and not more than the minimum particle diameter of the filtration part formation material particles is arranged inside the filtration part formation particle layer; On the inside of the reticulated metal body, 2 to the average particle diameter of the filtration portion forming material particles
Forming a support part forming particle layer with a support part forming metal particle having an average particle diameter of twice or more, temporarily forming the filtration part forming particle layer, the reticulated metal body, and the support part forming particle layer integrally. A point is that a cylindrical molded body is formed, and the cylindrical molded body is sintered under isotropic pressure. According to the sixth characterizing feature [effects of the sixth characterizing feature], so the metallic filter can be easily manufactured. That is, it is possible to easily manufacture an integrally formed metal filter while assigning different roles to the filtering unit and the supporting unit. In other words, while the different roles in the a support section Filtration section, the transmission hole diameter of the support portion is sufficiently large, while maintaining a low Sekiri without ventilation pressure loss in the thickness of the support portion, depending on the purpose It is possible to easily manufacture an integrally molded metal filter having high filtration accuracy and high strength. Therefore, it is possible to sufficiently maintain the strength of the metal filter while keeping the ventilation resistance sufficiently low. As a result, the ventilation pressure loss of the metal filter can be kept lower.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the above-described metal filter of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of the metal filter of the present invention used for exhaust gas dust removal of a waste incinerator, and FIG. 2 shows a cross section of a main part thereof. As shown in FIG. 1, a metal filter F is a filter body 1 formed by sintering metal particles into a cylindrical shape.
And a bottom plate 2 made of Inconel for closing one end of the filter body 1 and a flange 3 also made of Inconel attached to the other end, are integrally formed by nickel brazing. The metal filter F distributes exhaust gas from the waste incinerator from the outside to the inside.
With this configuration, the bag filter can be used in place of the bag of the bag filter, so that dust removal in high-temperature exhaust gas and back-pressure cleaning with high-pressure gas can be performed. Moreover, as described later, since the ventilation pressure loss is low, the filtration area can be reduced as compared with the conventional bag filter, and there is no possibility that the aperture will be changed by back pressure cleaning, so that the filter can be stably used for a long time. Can be used as dust removing means.

As shown in FIG. 2, the filter body 1 has a filtering part 1a having a thickness of about 0.6 mm and a supporting part 1b having a thickness of about 1.4 mm disposed inside the filtering part 1a. An outer diameter of about 1 mm formed by sintering under pressure under isotropic pressure integrally with the front and back sides in a state where a mesh metal body 7 having a thickness of about 0.1 mm is interposed in the portion 1c.
It is a 00 mm cylinder.

The filtering portion 1a is formed by layering Hastelloy particles 5A as small-diameter filtering portion forming material particles 5, and the supporting portion 1b is formed of a supporting portion forming metal particle having a larger diameter than the Hastelloy particles 5A. Inconel particles 6 </ b> A serving as particles 6 are formed by laminating inside the reticulated metal body 7. The reticulated metal body 7 is formed of a nickel wire mesh 7A. Both Hastelloy and Inconel are nickel-based high-temperature corrosion-resistant metals, and are favorably sintered using the reticulated metal body 7 composed of a nickel wire mesh 7A interposed therebetween as an intermediate metal.

The Hastelloy particles 5A forming the filtration part 1a are manufactured by a gas atomizing method, and are classified to have a particle diameter (-145 + 170 mesh) within a range of 90 to 100 μm, and are sintered. The diameter of the transmission hole after the etching is 17 to 20 μm, and the minimum blocking particle size is 17 μm.
m. The nickel wire mesh 7A interposed inside is formed by knitting a nickel wire having a wire diameter of 0.053 mm, is smaller than 90 μm which is the minimum particle diameter of the Hastelloy particles 5A, and A mesh having a mesh size of 74 μm, which is larger than the transmission hole diameter of 1a (equivalent to JIS standard 200 mesh standard sieve) is used. Further, the Inconel particles 6A forming the support portion 1b formed inside thereof are also manufactured by a gas atomization method, and are classified by sieve to have a particle diameter of 300 to 420 μm.
m (-36 + 48 mesh).
The diameter of the through-hole after sintering is set to 50 to 100 μm so that the ventilation resistance does not increase even if the thickness of the support portion 1 b is increased.

By the way, if the diameter of the transmission hole is 100 μm,
If the nickel wire mesh 7A is not interposed, the Hastelloy particles 5A may enter the through-holes and close the through-holes. That is, when the nickel metal net 7A, which is the reticulated metal body 7, is not used, the particle size range of the Inconel particles 6A forming the support portion 1b is such that the Hastelloy particles 5A forming the filtration portion 1a are located between the Inconel particles 6A. It must be set so that it is not filled. For example, the average particle size of the filtration part forming material particles 6 is 100 μm, and the particle size distribution ratio (the particle size of the cumulative frequency 95% and the cumulative frequency 5% in the volume-based cumulative distribution curve of the particle size of the filtration part forming material particles 5) In the case of sintering Hastelloy particles 5A having a value obtained by dividing the difference from the average particle size by an average particle size) of about 1, the average particle diameter of the support-forming metal particles 6 should not exceed 300 μm. Is desirable. In addition, the diameter of the permeation hole formed in the above-mentioned filtration part 1a was 27 μm, and the distribution ratio of the permeation hole diameter was about 0.1. This makes it possible to easily produce a metal filter having a sufficient strength with a minimum blocking particle size of about 30 μm, low airflow resistance, and no risk of high-temperature corrosion.

An example of a method for manufacturing the metal filter of the present invention will be described below with reference to FIGS. First, as shown in FIG.
m, while rotating the centrifugal molding die 20 at a high speed, a 145 mesh sieve was previously placed on the inner surface of the
Hastelloy particles 5A as filtration part forming material particles 5 classified on a mesh sieve (particle size range of about 90 to 100 μm)
Is injected as a slurry 12 for forming a filtration part in which a dispersant and a binder are blended using water as a dispersion medium L. The rotation speed of the centrifugal molding die 20 is set to such an extent that the centrifugal field exerted on the filtration part forming material particles 5 to be injected is sufficient. The centrifugal molding die 20 is attached to the rotating frame 20b by the die main body 20a.
And weirs 21 are arranged at both ends thereof,
The fixing members 20c are disposed on both sides of the fixing members 20c, 2c.
The mold body 20a is fixed to the rotary frame 20b by fastening the end plate 22 to the rotary frame 20b from both sides of the rotary frame 20b. The centrifugal molding die 20
Are supported by a pair of rollers 23 near both ends,
The roller 23 is driven to rotate by the driving rotation of the roller 23. A heater block H is provided to cover the mounting position of the mold main body 20a of the centrifugal mold 20. The heater block H is divided into two in the circumferential direction.
4, a heater 25 is arranged inside. A predetermined amount of the slurry 12 for forming a filtration part is supplied to a hopper 30b of an injection trough 30, and an injection port 30a is inserted from a material injection port 21a of the weir 21 while maintaining a suspension state. 20a, and the slurry 12 for forming the filtration section is injected.
When the injection is completed, the injection trough 30 is retired, the rotation of the centrifugal molding die 20 is maintained as it is, and the slurry 12 for forming the filtration portion is gravity-separated.
Is separated from the dispersion medium L and is deposited on the inner surface of the mold body 20a to form a settling layer D (see FIG. 4). When the sedimentation layer D starts to be formed, it is overheated by the heater 25 and at the same time the end plate 2 at the end of the centrifugal molding die 20.
2, an air blowing pipe 26 is inserted through the opening, and drying air is blown into the weir 21 (see FIG. 4) to evaporate the dispersion medium L of the filtration part forming slurry 12, thereby forming the die body. A filtration part forming particle layer 8 is formed on the inner surface of the substrate 20a (FIG. 5).
reference). When the formation of the filtration portion forming particle layer 8 is completed, the air blowing tube 26 is pulled out, and as shown in FIG. 5, a nickel wire mesh 7A equivalent to a JIS standard 200 mesh standard sieve as a finely wound mesh metal body 7 is formed. The end plate 22 is inserted into the weir 21 through the material injection port 21a through the opening, and rotated with the centrifugal molding die 20 to be developed by centrifugal force. A nickel wire mesh 7A is arranged as the mesh metal body 7. When the arrangement of the nickel wire mesh 7A is completed, as shown in FIG.
In the hopper 30b, similarly to the filtration part forming slurry 12,
Classification under 36 mesh sieve and 48 mesh sieve (about 300
４００400 μm) and a predetermined amount of the slurry 13 for forming the support portion is supplied, and the suspension trough 30 is maintained.
Is inserted from the material injection port 21a of the weir 21, and the support forming slurry 13 is injected into the nickel wire mesh 7A, and the centrifugal molding die 20 is kept rotating as it is. The support portion forming slurry 13 is gravity-separated, the support portion forming metal particles 6 are separated from the dispersion medium L, deposited on the inner surface of the nickel wire mesh 7A, and dried in the same manner as the filtration portion forming slurry 12. Then, the support portion forming metal particle layer 9 is formed. When the slurry 13 for forming the support portion is injected into the filter portion forming particle layer 8, the nickel wire mesh 7 </ b> A is present on the inner surface of the filter portion forming particle layer 8. No. 8 is not washed and a separated layer is surely formed with the layer thickness kept uniform. It is preferable that the dispersing agent to be blended in the slurry 12 for forming the filtering portion and the slurry 13 for forming the supporting portion is one which easily evaporates when the dispersion medium L is evaporated. It is necessary that the sintering of the part-forming material particles 5, the support part-forming metal particles 6, and the reticulated metal body 7 is not hindered, but a water-soluble binder, a water-soluble resin, or the like can be used. is there.

When the formation of the support-forming metal particle layer 9 is completed, the rotation of the centrifugal molding die 20 is stopped, the end plate 22 at one end is removed, and the fixing material 20 at the one end is further removed.
c and the weir 21 are extracted, and the cylindrical molded body 10 including the filtered part forming particle layer 8, the reticulated metal body 7, and the support part forming particle layer 9 after molding is taken out from the centrifugal molding die 20. The metal filter F is manufactured by charging into an isotropic pressure sintering apparatus, sintering the filter body 1 and brazing the flange 3 and the bottom plate 2 together.

Next, another embodiment of the present invention will be described. <1> In the above-described embodiment, Hastelloy particles are used as the filtration part forming material particles 5 and the support part forming metal particles 6 are used.
As an example, inconel particles were used, but the material of the filtration portion forming material was SUS304 or SUS304 depending on the purpose.
316, 316L stainless steel, titanium, titanium alloy, chromium, chromium alloy and other corrosion-resistant metal materials, heat-resistant metal materials, or one or more metals selected from high-temperature corrosion-resistant metal materials Or may be made of one or more kinds of ceramics selected from ceramic materials such as cordierite, and further, a mixture of ceramic particles and metal particles having good compatibility. May be done. Further, the support portion forming material particles 6 may be made of the same material as the filtration portion forming material particles 5. <2> In the above-described embodiment, an example in which the nickel metal mesh 7A is used as the mesh metal body 7 has been described, but SUS3 is used as the metal material forming the mesh metal body 7 according to the purpose.
04, SUS316, SUS316L, etc., one or more metal materials selected from corrosion-resistant metal materials such as titanium, titanium alloys, chromium, chromium alloys, heat-resistant metal materials, and high-temperature corrosion-resistant metal materials May be used. <3> In the above-described embodiment, an example has been described in which the particle size of the filtration portion forming material particles 5 is set to a particle size falling within a range of 90 to 100 μm, but the particle size is set arbitrarily. Therefore, the average particle size or the maximum particle size and the particle size range may be set according to the required minimum blocking particle size, and the above-mentioned permeation hole size distribution ratio is set according to the purpose, and corresponding thereto. What is necessary is just to set the particle size distribution ratio of the filtration part forming material particles 5 to be performed. As described above, the transmission pore size distribution ratio shows a strong correlation with the particle size distribution ratio. According to the measurement results, the regression coefficient of the particle size distribution ratio with respect to the transmission pore size distribution ratio is about 0.5.
The contribution ratio was about 0.04, and the regression line and the measured permeation hole diameter were in very good agreement. <4> In the above embodiment, an example was described in which the nickel metal mesh 7A was used as the mesh metal member 7, but the mesh metal member 7 may be omitted. The aperture, the wire diameter, and the like of the reticulated metal body 7 are set mainly by the particle size distribution of the filtration portion forming material particles. <5> In the above-described embodiment, an example has been described in which the particle diameter of the support portion forming metal particles 6 is set to a particle diameter falling within the range of 300 to 450 μm. The average particle diameter of the support-portion-forming metal particles 6 is equal to or less than three times the average particle diameter of the filtration-portion-forming material particles 5 as in the above embodiment. The diameter is preferably smaller than twice the minimum particle diameter of the filtration portion forming material particles 5, and more preferably larger than 1.2 times. Within this particle size range, the particles of the filtering portion forming material particles 5 do not enter between the particles of the supporting portion forming metal particles 6, and the formation of the supporting portion 1b does not impair the air permeability of the metal filter. In addition, by providing the support portion 1b, it is possible to avoid increasing the ventilation resistance of the metal filter. <6> In the above embodiment, an example is shown in which the support portion 1b is disposed inside the filtration portion 1a and formed in a cylindrical shape.
The support part 1b may be formed outside the filtration part 1a. Further, the filter 1a may be a filter formed in a plane with the support 1b. <7> In the above embodiment, the filtration part forming particle layer 8
And an example in which the support-forming particle layer 9 is formed by centrifugal molding,
Both or one of them may be formed by applying a paste of forming particles, or may be formed on a molding surface of a sintered mold by dry centrifugal molding. <8> In the above embodiment, the filtration part forming particle layer 8
Although an example in which the mesh-like metal body 7 made of a wire mesh is attached to the inner surface of the mesh by centrifugal force accompanying rotation, the mesh-like metal body 7 may be a porous metal plate or a metal film formed in a mesh shape, The arrangement of the filtration section forming particle layer 8 on the inner surface may be applied to the stationary inner surface of the filtration section forming particle layer 8 even in the above-described centrifugal molding. In this case, when used for the filtration part forming particle layer 8, it may be attached using a binder of the same quality or a different adhesive substance. <9> The setting of the acceleration of the centrifugal field exerted on the filtration part forming material particles 5 injected by the rotation speed of the centrifugal molding die 20 is arbitrary, and depends on the properties of the filtration part forming material particles 5 and the dispersion medium L. It must be determined. For example, when the specific gravity difference between the filtration part forming material particles 5 and the dispersion medium L is small, or when the kinematic viscosity of the dispersion medium L is high, it is advisable to use a high rotation speed in order to shorten the molding time. It is.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view of a main part of a metal filter according to the present invention.

FIG. 2 is a sectional view of an essential part for explaining an example of a configuration of a metal filter of the present invention.

FIG. 3 is a schematic longitudinal sectional view of a forming apparatus showing an example of a preforming step of a method for manufacturing a metal filter.

FIG. 4 is a schematic longitudinal sectional view of a molding apparatus illustrating a preforming step following the step shown in FIG. 3;

FIG. 5 is a schematic vertical sectional view of a molding apparatus for explaining a preforming step following the step shown in FIG. 4;

FIG. 6 is a schematic vertical sectional view of a molding apparatus for explaining a preforming step following the step shown in FIG. 5;

FIG. 7 is a schematic explanatory view of a step after preforming of the present invention.

[Explanation of symbols]

The volume of transmission hole diameter D ₅₀ transmission aperture diameter of the cumulative frequency 5% in volume-based distribution curve of 1a filtering portion 1b supports 7 mesh metal body 8 filtration unit forming particle layer 9 supporting part particle layer 10 cylindrical molded body D ₅ permeation pore diameter Permeation pore diameter with a cumulative frequency of 50% in the reference distribution curve D ₉₅ Permeation pore diameter with a cumulative frequency of 95% in the volume-based distribution curve of the permeation pore diameter

──────────────────────────────────────────────────続 き Continuing on the front page (72) Atsushi Funakoshi 1-1-1, Nakamiya Oike, Hirakata City, Osaka Prefecture Inside Kubota Hirakata Plant (72) Inventor Takashi Nishi 1-1-1, Nakamiya Oike, Hirakata City, Osaka Prefecture No. Kubota Corporation, Hirakata Factory (72) Inventor Akira Kosaka 1-1-1, Nakamiya Oike, Hirakata City, Osaka Prefecture Inside Kubota Corporation, Hirakata Factory (56) References JP-A-6-327920 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B01D 39/00-39/20

Claims (6)

(57) [Claims] 1. A metal filter formed by sintering metal particles in a cylindrical shape, the filter comprising a filter member forming material having a small diameter;
A support part (1b) made of support part formation metal particles having a diameter larger than that of the filtration part formation material particles is formed by sintering the front and back parts integrally under isostatic pressure, and the support part formation metal particles are Said
Average particles less than 3 times the average particle size of the filtration part forming material particles
Metal filters are assumed diameter. 2. The filter (1a) and the support (1)
2. The metal filter according to claim 1, wherein the metal filter is integrally formed by sintering with a mesh metal body (7) having an opening of not more than the minimum particle diameter of the filtration portion forming material particles between the filter member and b). 3. The method according to claim 1, wherein the filtering section (1a) is provided with a transmission hole diameter D _{5 having} a cumulative frequency of 5% in a volume-based cumulative distribution curve of the transmission hole diameter.
When a cumulative frequency of 50% of the transmission hole diameter D _50, the cumulative frequency 95%
Transmission hole diameter D ₉₅ and _{is, (D 95 -D 5) /} D metal filter according to claim 1 or 2 is as an indication of the transmission hole distribution satisfying the relationship of ₅₀ ≦ 1.5 in. 4. The metal filter according to claim 2, wherein the openings of the mesh-like metal body (7) are set to 30% or more of the average particle diameter of the filtration part forming material particles. Wherein said filtration unit forming material particles and the metal filter according to any one of claims 1-4 wherein the support portion forming metal particles in which both consist of high temperature corrosion resistant metal. 6. A filtration part forming material layer (8) is formed from the filtration part forming material particles on the inner surface of a cylindrical mold, and the filtration part forming material particles are formed inside the filtration part formation particle layer (8). A mesh metal body (7) having an opening of 30% or more of the particle diameter and equal to or less than the minimum particle diameter of the filtration part forming material particles is disposed, and the filtration part formation is formed inside the mesh metal body (7). The support-forming particle layer (9) is formed of the support-forming metal particles having an average particle diameter that is twice or more the average particle diameter of the material particles, and the filtration unit-forming particle layer (8) and the reticulated metal Body (7),
Manufacture of a metal filter in which a cylindrical molded body (10) is formed by temporarily forming the support-forming particle layer (9) integrally, and the cylindrical molded body (10) is sintered under isotropic pressure. Method.