JP2606925Y2 - Laminated filter media - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated filter medium which can prevent the fluid to be treated from remaining on a protective screen and improve the bonding strength of each layer.

[0002]

2. Description of the Related Art For example, as a filter medium used in a filtration treatment for removing and separating fine particles in a liquid, materials and forms corresponding to the properties of the fluid to be treated have been developed. Sintered metal is
It is widely used due to its many advantages such as heat resistance, corrosion resistance, mechanical strength, and ease of processing.

As a device using such a filter medium made of a metal sintered body, the present applicant has disclosed, for example, Japanese Utility Model Application Laid-Open No. 59-176.
No. 615 proposes a laminated filter medium in which a protective screen is arranged on at least one side of a filter medium using a fine metal such as a metal fiber and sintered and integrated.

[0004] Such a protective screen of a laminated filter medium is
It is used for reinforcement of the filter medium and protection of the filter medium for preventing a change in properties such as a pore diameter due to a loss of fibers in the filter medium during handling or the like.

In recent years, in particular, in order to improve filtration accuracy and filtration efficiency, filter materials have been made as thin as possible to reduce flow resistance. In such a filter material, a protective screen is indispensable.

[0006]

However, due to recent demands for higher filtration performance, a sintered body obtained by sintering fine fibers having a fiber diameter of several μm may be used as a filter medium. When such a filter medium is used, the protective screen usually has a thickness of 0.1 to prevent the filtration characteristics from being impaired.
When a wire material forming a meridian and a latitude line of the protection screen is adopted, which is corrugated in the thickness direction, a thin wire material of about 1 to 0.5 mm is used.
The substantial joining surface between them is very small.

As a result, the two are inferior in bonding strength, easily peeled off during handling and post-processing, and cannot function as a protective screen. Further, such a tendency is increased by miniaturization and miniaturization of the constituent members of the filter medium as described above.

In order to solve these problems, it is conceivable to increase the bonding area by narrowing the protective screen and the filter medium so as to bite the filter medium into the protective screen in order to bond the two with a larger bonding area. In particular, immediately below the intersection, the filter medium is pressed and deformed to locally reduce the pore diameter, worsening the flow and impairing the filtration characteristics such as retention.

It has been tested experimentally that a protective screen flattened by pressing both sides, a reinforcing plate such as a punching plate, and the like, are used to increase the contact area and improve the bonding strength without deforming the filter medium. However, in such a reinforcing plate, the ratio of the non-opening portion to the entire area is considerably large, for example, about 40 to 50%. The fluid to be treated cannot be completely flowed in, and the substantial filtration process is limited only to the opening, so that satisfactory filtration efficiency cannot be obtained.

In addition, the stagnation phenomenon is liable to occur in the non-opening portion. For example, when the fluid to be treated is the high-viscosity polymer or the like, a gel is generated due to the deterioration of the polymer and is mixed therewith, which causes a problem that the product quality is deteriorated. .

[0011] The present invention solves the above-mentioned problems by interposing and integrating a dispersion layer having predetermined characteristics between the filter medium and the filter medium while using a protective screen, thereby providing a laminated filter medium having excellent mechanical strength and filtration characteristics. It is intended to be provided.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a filter material layer using fine elements on a protective screen in the form of a sheet formed by crossing wires and woven through a dispersion layer bonded to one surface of the protective screen. as well as integrally connected to, before
In the protective screen, at the intersection of the wire, the wire is
By being flattened in parallel with the sheet surface, the dispersion layer
A flat part is formed on at least one side to increase the bonding strength of the
In addition, the average pore diameter of the dispersion layer is larger than the average pore diameter of the filter medium layer, and the thickness thereof is 0.3 to 5 times the width W of the flat portion of the protective screen. It is a laminated filter medium.

[0013]

As described above, in the laminated filter medium of the present invention, the protective screen having the flat portion and the filter medium layer are connected via the dispersion layer having a predetermined thickness, and the dispersion layer is larger than the filter medium layer. By having a pore diameter, the fluid to be treated can easily flow into the inside of the laminated filter medium.

For this reason, even if a large non-opening portion is formed in the protective screen, the fluid to be treated easily enters immediately below the protective screen, and is substantially uniform before reaching the filter medium layer on the downstream side. Therefore, stagnation can be prevented by performing filtration using the entire surface of the filter medium layer effectively.

In addition, the dispersion layer can relieve the filtration pressure acting on the filter medium layer, and can also function as a pre-filter layer for removing relatively large foreign matters, thereby contributing to a longer life of the laminated filter medium.

The flat portion formed at the intersection of the wires of the protective screen increases the bonding area with the dispersing layer, and when the element of the dispersing layer is made larger in diameter than the element of the filter medium, the protective screen and the dispersing layer have a larger diameter. The bonding strength is further increased, and the above-described peeling due to insufficient bonding is reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged perspective view showing one embodiment of the laminated filter medium 1 according to the present invention, and FIG. 2 is a sectional view showing another embodiment.

As shown in FIG. 1, the laminated filter medium 1 has, for example, a dispersion of pores larger than the filter medium layer 3 between a protective screen 2 arranged on the upstream side and a filter medium layer 3 arranged on the downstream side. The layer 4 is arranged and the whole is sintered and integrated.

The protective screen 2 is in the form of a sheet formed by intersecting and weaving a wire 2 composed of a meridian 2A and a weft 2B. In the present example, the flattened protective screen 2 in which the wire 2 at the intersection 2C is deformed by pressing both surfaces of the sheet-like body and the flat portions 2D are provided on both surfaces is used. The protective screen 2 may be one in which the flat portion 2D is formed only on the surface in contact with the dispersion layer 4 by, for example, grinding or polishing.

The wire 2 of the protective screen 2 is, for example, a thin stainless steel wire of 0.1 to 0.5 mm.
A sheet-like woven body woven to about 00 # is preferred.

When the flat portion 2D is formed by, for example, pressing (rolling), the rolling reduction (T) is set to 10 to 50%.
The rolling reduction is defined as the difference (T0) between the woven thickness (T0) of the woven body and the thickness (T1) after pressing as shown in the following equation.
−T1) to the ratio of the woven thickness (T0). Reduction ratio (T) = (T0−T1) / TO × 100

When the rolling reduction is 10% or less, a flat portion having a size necessary to increase the bonding strength is not obtained, and a high bonding strength cannot be obtained. The widening reduces the area of the opening 5 between them, substantially reducing the flow area. When pressed (rolled), the height of each flat portion 2D becomes uniform over the entirety, and a flat portion having a desired thickness can be obtained. In particular, when stainless steel is used, a hard screen is formed by work hardening. . Also, since the woven body is used, the wire is less likely to expand and contract and is excellent in the reinforcing effect. Further, even at the intersection of the wires, the wires are dented and deformed and bite, so that the wires can be engaged with each other so that there is no screen misalignment.

From such a viewpoint, the rolling reduction T is 10
To 50%, preferably 20 to 50%, more preferably 30 to 45%.

The above reduction ratio (T) is 10 to 50%.
Therefore, the width W of the flat portion 2D is about 0.3 to 1.1 times the diameter d of the wire before rolling down, when the meridian 2A and the weft 2B have the same diameter and the same kind of circular cross-section wire. Become. The width W of the flat portion 2D refers to the maximum dimension of the flat portion 2D in a direction perpendicular to the longitudinal direction of the meridian 2A or the latitude line 2B.

The woven body may be of a general plain weave or of a different woven structure such as a twill weave, a tatami weave, or the like, in which pitches are changed, and wires of different thicknesses are used for the meridian and the weft. Adopted. In the case of wires with different thicknesses,
The flat width W is the maximum width.

On the other hand, the filter medium layer 3 substantially filters the fluid to be treated, and guarantees the filtration performance. The filter medium layer 3 has a single layer as shown in FIG. As shown in FIG. 2, a two-layer structure of a finest and thinner first filter medium layer 3A on the most downstream side and a second filter medium layer 3B slightly coarser and thicker than the first filter medium layer 3A on the upstream side, for example It can also be a body.

Further, a multi-layer structure may be used, and an increase in the number of layers generally improves the filtration efficiency. In the case of FIG. 2, the flat portion 2D is formed on the protective screen 2 only on one side (lower surface) by grinding.

The filter medium layer 3 may be made of, for example, stainless steel, a metal long fiber, a metal short fiber, a metal powder, or a mixture of any of various metals or alloy materials such as nickel, chromium, aluminum, and copper. The sintered body of the fine element is used.

When the liquid to be treated is a high-temperature and high-viscosity fluid such as a polymer, for example, a stainless steel short fiber sintered body, which is disclosed in JP-B-63-5443 and JP-B-63
No. 63645, Japanese Patent Publication No. 63-31521, and the like.
The one using about 5 short fibers can be preferably employed because a sintered body having a fine, uniform and high porosity can be obtained. When the filter medium layer 3 uses one filter layer as shown in FIG. 1, its thickness is about 0.02 to 2 mm, usually 0.3 to 1.0 mm, and is intended to improve the filtration efficiency. At times, for example, a membrane filter medium of about 0.5 to 0.02 mm is used.

Further, even when the fluid to be treated is a polymer,
When a high-quality polymer, for example, a polymer for a film (video film), is used, it is necessary to completely remove even fine foreign substances.
μm or less (preferably 5 μm or less),
The porosity may be free.

As shown in FIG. 2 , the filter medium layer 3 has two layers.
When using the filtration layer, the first filtration layer 3A, for example, the following atomized powder particles having a particle diameter 5 [mu] m,
Or 0.1 to 20 μm in diameter and average aspect ratio of 2 to 50
A sintered product using short metal fibers or the like can be used. In particular, a sintered product using short metal fibers has three-dimensional pores and low pressure loss. Note that a sintered product of a mixture of short metal fibers and powder particles can also be used.

Further, the use of the short fibers can reduce the variation in the pore diameter, so that the thickness can be reduced to 10 to 500 μm, preferably 20 to 100 μm.
Further, the pressure loss can be further reduced by reducing the thickness.

The second filtration layer 3B is formed of the filtration layer 3A.
It has a hole with a larger diameter than that of the first filter layer 3A and supports relatively large impurities prior to the filter layer 3A, thereby increasing the pressure loss while extending the filtration life of the filter layer 3A. Suppress.

For this purpose, the pore size of the second filtration layer 3B is preferably gradually increased toward the upstream side. For this reason, two or more layers having different fiber diameters and filtration diameters are sequentially laminated. It may be formed as a laminate.

As the second filtration layer 3B, similarly to the first filtration layer 3A, a sintered product such as metal particles, metal fibers, metal short fibers or a mixture thereof can be used. The height is about 0.2 to 2 mm.

In order to form such a thin first filtration layer 3A having a small pore diameter integrally with the second filtration layer 3B, Japanese Patent Application No. 3-289087 proposed by the present applicant has been proposed. That is, a method in which a suspension in which metal particles are suspended in advance is suction-attached to one surface of the second filtration layer 3B manufactured in advance with a predetermined thickness, and then sintered.

On the other hand, the dispersion layer 4 is in contact with the flat portion 2D of the protective screen 2 and has an average pore diameter larger than that of the filter medium layer 3 as described above to prevent clogging. 4 is preferably stainless steel fiber,
Nickel fiber, Hastelloy fiber, etc.
It is formed by sintering a fibrous nonwoven fabric made of a metal fiber having a thickness of 0 μm, preferably about 15 to 50 μm to a predetermined thickness under pressure. The average pore diameter can also be known by measuring the cross section with a microscope or the like, for example.

The thickness of the dispersion layer 4 is 0.3 to 5 times the width W of the flat portion 2D formed on the protective screen 2, and is about 0.1 to 1.0 mm. If it is less than 0.3 times, a sufficient gap for uniform flow between the protective screen 2 and the filter medium layer 3 cannot be provided, and the entire surface of the filter medium layer 3 cannot be effectively utilized. If it exceeds 5 times, the total thickness increases, more preferably about 0.5 to 3 times.

In the case of FIG. 1, the dispersing layer 4 is made of a sintered material of stainless steel fiber in the same
mm, and the thickness corresponds to about 0.9 times the width W of the flat portion 2D. Also, as described above, an element made of relatively thick metal fiber is used, and
By randomly distributing these in a plane, the pore diameter is made larger than the pore diameter of the filter medium layer 3 on the downstream side.

In the dispersion layer 4 composed of such metal fibers, the porosity is larger than that of the sintered body using the powder by 50 to 50%.
It is about 80% and has excellent flexibility, so even if it is relatively thin, there is no problem such as cracking,
Also, it can exhibit the function of filtration pressure buffering. Furthermore, since the pore diameter is larger than the pore diameter of the filter medium layer 3 on the downstream side, the flow of the liquid to be treated is improved by filtering, and problems such as stagnation are improved.

More preferred specific examples of the dispersion layer 4 include:
A 316L stainless steel fiber having a fiber diameter of 20 μm is porosity 55
%, And the pore diameter is reduced to about 17 μm. As shown in FIG. 1, the pores 2D are interposed and integrally connected between the uneven plane 2D of the protective screen 2 and the filter medium 3.

In order to use the laminated filter medium 1, when the protective screen 2 is used alone as the upstream side, for example, a filter plate 7 having a wire mesh or a sintered body as a support member is provided on the downstream side. You can also. As shown in FIG. 3, as the support member 9, for example, a support plate 10 formed of a punching plate, a screen 12 supported by the support plate 10, a sintered layer 13 of metal fine particles such as short metal fibers and atomized powder, Can be used. At this time, the screen 12 having the same configuration as the above-described protective screen 2 can be used.

The sintered layer 13 can be a filter medium layer 15 similar to the filter medium layer 3 and a fiber layer 16 similar to the dispersion layer 4.

The filter medium layer 15 includes the first and second filter medium layers 3.
A, 3B, first and second filter medium layers 15A, 15B
The first filter medium layer 15A for microfiltration is disposed on the most upstream side.

With such a structure, a hole structure is formed as a whole that becomes coarser from coarser to denser, and a rapid change in flow velocity can be prevented to prevent stagnation, and adopted for various filters such as a leaf filter and a tube filter. Can. Also, each member can be variously deformed, for example, by mixing both at the boundary of each layer or forming an uneven shape.

(Specific Example) In order to evaluate the characteristics of the filter medium of the present invention as a filter member,
First, as shown in Table 1, an example product, a comparative example product 1 (a protective screen having no flat portion and a filtration layer were directly laminated and sintered ... no dispersion layer), and a comparative example product 2 (the flat portion was A protective screen that does not have a filter screen that cuts into the filter medium layer, sinters it with a sufficient bonding area ... no dispersion layer), Comparative example product 3
(A protective screen having an uneven plane due to pressing both sides, laminated on a filter medium layer and sintered; no dispersion layer) was prepared.

The laminated filter medium is a leaf filter having an outer diameter of 300 mm by arranging two filter plates 7 and 7 each having a support member 9 as shown in FIG. Was formed, and the leaf filter was set on a center post having a height of 100 mm to constitute a filtration device.

On the other hand, the fluid to be treated has a temperature of 300 ° C.
5 hours / hour using polyethylene terephthalate polymer
Table 1 also shows the results of continuous filtration at a flow rate of 0 kg.

[0049]

[Table 1]

In Table 1, the term "pressure loss" refers to the pressure difference before and after the filtration device, and the term "easiness of washing" refers to the fact that polyethylene terephthalate is filtered, then immersed in triethylene glycol, heat treated, and polymer ash remaining in the filter The judgment is made based on the length of time (the number of times of processing) required for removing foreign matter and the like by ultrasonic cleaning.

As is clear from Table 1, which is the measurement results under the same conditions, the time required for gel generation of the laminated filter medium of the present invention is 202 hours, which is the longest. It turns out that it is excellent. In addition, the protective screen of the example product has an uneven flat surface, and a dispersion layer that can relatively increase the bonding area is interposed between the protective screen and the filter medium layer. Did not occur.

[0052]

As described above, the laminated filter medium of the invention of the present invention has a high dispersion strength and a high filtration efficiency by providing a dispersion layer between the protective screen and the filter medium layer. It can be used effectively for filtration of viscous fluids.

[Brief description of the drawings]

FIG. 1 is an enlarged perspective view showing one embodiment of a laminated filter medium of the present invention.

FIG. 2 is a sectional view showing another embodiment of the laminated filter medium.

FIG. 3 is a perspective view illustrating an example of using a laminated filter medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated filter medium 2 Protective screen 2C Crossing part 2D Flat part 3 Filter medium layer 4 Dispersion layer

Claims (3)

(57) [Scope of request for utility model registration] 1. A filter material layer using fine elements is integrally bonded to a sheet-like protective screen formed by crossing wires and woven into a sheet through a dispersion layer bonded to one surface of the protective screen. And at the intersection of the wires,
Is flattened in parallel with the sheet surface so that the dispersion layer
Flat section is formed on at least one side to increase the bonding strength
In addition, the average pore diameter of the dispersion layer is larger than the average pore diameter of the filter medium layer, and the thickness thereof is 0.3 to 5 times the width W of the flat portion of the protective screen. Laminated filter media. 2. The filter medium layer according to claim 1, wherein the filter medium layer is a single filter layer or a first filter layer.
A filtration layer and a first filtration layer having a large diameter hole
2. The laminated filter medium according to claim 1, comprising two filter layers including a second filter layer . 3. The protective screen according to claim 1, wherein the rolling reduction is 10 to 50.
The laminated filter medium according to claim 1, wherein the flat portions are formed on both surfaces by pressing the filter media in%.