JP3884133B2 - Laminated metal filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminated metal filter which is suitably used for filtering a high viscosity fluid such as a molten polymer, and which enables low pressure loss.
[0002]
[Prior art]
In the field of chemical fibers, the quality of spinning and film formation is improved by removing foreign substances in the molten polymer with a metal filter.
[0003]
As a filter currently used in such applications, for example, a leaf-shaped filter is proposed by Japanese Utility Model Publication No. 64-980 and the like, and as illustrated in FIG. And a support member B such as a net-like body that is directly or indirectly supported on the downstream side thereof, and a disk-like one integrated by welding the outer periphery of the filter medium A is often used. .
[0004]
In this case, the support member B has a mesh of about several mesh that is plain-woven with a fine metal wire of about 0.8 mmφ, for example, in order to secure the strength to support the filtration pressure applied to the filter medium A and the outflow passage through which the filtered molten polymer passes. A relatively coarse mesh is used.
[0005]
In the conventional filter as well, in order to prevent the convex portion C of the mesh body, which is a bent portion of the fine metal wire, from pressing the filter medium and locally crushing and clogging the pores of the filter medium, the filter medium A and the support member In some cases, an insertion member D such as a punching plate or a powder sintered body is disposed between B and B.
[0006]
[Problems to be solved by the invention]
By the way, especially when the fluid to be treated is a chemical polymer that is likely to change with time, for example, a smooth discharge of the fluid to be treated filtered with a filter medium and a decrease in flow resistance are desired. Have found that it is important to be able to improve this support and improve the performance.
[0007]
That is, when the filter medium is directly supported by the mesh body, the filter medium is directly supported by the convex portion formed by the intersection of the mesh body with the meridian and the latitude line, so that the meridian and the latitude line intersect at a relatively narrow pitch interval. Therefore, it is necessary to increase the number of intersections and reduce the load pressure applied to each intersection.
[0008]
However, such a thing increases the number of wires, and accordingly, the effective passage area occupied in the outflow passage decreases, impedes the outflow of the fluid to be treated, and sometimes increases the chance of generating its retention, etc. It has been difficult to obtain high quality filtered melt polymers.
[0009]
Note that simply increasing the line spacing and reducing the number of pipes used to increase the outflow passage will reduce the number of support points for supporting the filter medium, thereby increasing the contact pressure with the filter medium and reducing the filter holes. Clogging occurs, and sometimes the filter medium itself cannot withstand the filtration pressure, resulting in deformation and breakage.
[0010]
In addition, such conventional support members are manufactured by machine weaving (plain weaving), and it is difficult to completely remove the processing foreign matter and impurities generated during the net making due to residual impurities remaining in the intersections. There is also a problem that it is peeled off and mixed with the fluid to be treated to lower the quality.
[0011]
As other support members other than the net-like body, for example, a corrugated metal flat wire formed into a spiral state (for example, Japanese Utility Model No. 1-148813), and an inverted metal flat wire arranged side by side in the outflow direction (for example, Japanese Laid-Open Patent Publication No. 64-4210) is also known. However, such a support member requires labor for assembling and is difficult to handle due to its increased weight, and the former support member has a flat projection and a filter medium. This is not suitable for filtration of molten polymer and the like.
[0012]
An object of the present invention is to provide a multilayer metal filter capable of solving such a problem on the basis of weaving a bent portion of a wavy line by crossing thin lines.
[0013]
[Means for Solving the Problems]
The invention of claim 1 of the present invention is a laminated metal filter formed by laminating a metal filter medium and a support member that directly or indirectly supports the filter medium, and the support member uses a fine metal wire. A wavy line that is formed of a wavy line that is formed by a wavy line formed by repeating a concave portion and a convex bent portion is used for at least one of the meridian and the latitude line. One or more bent portions are skipped and woven with the other fine metal wires intersecting the bent portions.
[0014]
As a result, the crossing pitch of the fine metal wires can be increased as compared to the conventional mesh body in which the fine metal wires are crossed for each bent portion, the number of the fine metal wires can be reduced, and the support portion by the wavy lines, That is, while maintaining the number of convex portions on one side of the bent portion and providing substantially the same support strength, the number of meridians and parallels, or the number of intersections is reduced, thereby increasing the area of the outflow passage and fluid Reduces flow resistance and smoothes the flow. In addition, since the number of tubes used can be reduced substantially, it also helps to reduce the weight of the filter itself. Therefore, the two contradictory characteristics of lowering the resistance to filtrate flow and improving the resistance to filtration pressure can be achieved without sacrificing one of them. Which can be improved,
The invention of claim 2 is characterized in that an insertion member made of a punching plate or a metal powder sintered plate is disposed between the metal filter medium and the support member. Thereby, the convex portion at the intersection of the thin lines of the support member presses the filter medium locally by the filtration pressure, and the support strength can be increased while reliably preventing the occurrence of indentation, and the outflow passage can be enlarged.
[0015]
The invention of claim 3 is characterized in that the support member is woven by crimp weaving. At this time, since a wavy line that is preliminarily shaped in a wavy shape is used for both the meridian and the latitude line, there is no generation of foreign matters during weaving, biting into an intersection, etc., and the wavy line is washed in advance. Helps to clean the filter.
[0016]
Preferred Embodiment of the Invention
1 and 2 show an embodiment in which the laminated metal filter 1 of the present invention is used as a leaf filter. The laminated metal filter 1 includes a hollow disk-shaped filter medium 2 and a hollow that supports the filter medium 2. An insertion member 4 is disposed between the filter medium 2 and the support member 3 to prevent direct contact between the filter medium 2 and the support member 3. The insertion member 4 is supported by the convex portions of the support member 3 so as to prevent deformation, blocking, or clogging of the filter holes of the filter medium 2 due to the filtration pressure.
[0017]
Further, the outer peripheral edge of the filter medium 2 and the interposing member 4 is clamped at a portion exceeding the outer peripheral edge of the support member 3, and the peripheral edge of the clamped portion is welded and joined by melting. Further, the inner peripheral edge of each filter medium 2 is reinforced by a reinforcing ring 6 having a U-shaped cross section, and an inner ring 9 having lateral holes 7 arranged in parallel is interposed between the reinforcing rings 6 and 6 on both sides. The inner peripheral edge of the insertion member 4 may also be welded to the inner ring 9.
[0018]
Such a laminated metal filter 1 is stacked in multiple stages via spacers 10 indicated by a one-dot chain line in FIG. 2 and is placed in a filter tank (not shown), and a treatment liquid, for example, a high-pressure polymer is allowed to flow therethrough. Is passed through the filter medium 2 and the interposing member 4, flows through the support member 3, and is collected through the lateral hole 7.
[0019]
As the filter medium 2, a plate-like sintered body is preferably used which is sintered by randomly entwining fine metal fibers such as stainless steel and nickel steel with predetermined filter hole characteristics. In addition, a sintered body of a metal powder or a sintered body of a mixture of a metal powder and a short metal fiber can also be employed as the filter medium 2. Furthermore, depending on the type of the liquid to be treated and the processing conditions, such as those in which multiple layers of sintered bodies with different specifications such as filter pores and materials are laminated, and those in which a fine mesh wire mesh is laminated on the surface to protect the filter material surface layer Various settings can be made.
[0020]
Moreover, although the punching plate in which the several small hole was formed is used as the insertion member 4, the plate-shaped metal powder sintered compact of a coarse pore rather than the said filter medium 2 etc. can also be used.
[0021]
As shown in FIGS. 3 and 4, the support member 3 is formed of a mesh body in which meridians 11 and latitude lines 12 using fine metal wires are woven. Examples of the fine metal wires include heat-resistant metals such as stainless steel wires and nickel wires. In addition, a round wire having a thickness of 0.3 to 3.0 mm, a deformed wire, or the like is used. In addition, each part specification of a metal fine wire can be variously changed according to the use and state to be used. Further, the arrangement pitches P11 and P12 of meridians or latitudes may be the same or different, and it is usually preferable that the number per inch is about 2 to 5. When the number decreases, it is better to increase the thickness and improve the strength of the fine metal wire itself.
[0022]
For at least one of the meridian 11 and the latitude line 12, a wavy line 20 is used that is preliminarily shaped into a wave shape and crimped to repeat a bent portion 16 composed of a concave portion 14 and a convex portion 15 when the fine metal wire is viewed from one side. By using such a wavy line 20, it is possible to improve the shape maintaining property as a net-like body, and to increase the pitch interval.
[0023]
Further, when the wavy line 20 is used for both the meridian 11 and the latitude line 12, the reticulated body can be woven by a so-called crimping machine assembled by fitting the two, and the wavy line 20 is sufficiently washed before fitting. By doing so, it is possible to prevent foreign matter from remaining on the surface and intersection of each line of foreign matter accompanying weaving, as compared with a conventional automatic machine weaving method that weaves while folding.
[0024]
Further, the concave / convex pitch P16 between the bent portions 16 including the concave portions 14 and the convex portions 15 of the wavy wire 20 is preferably as small as possible in the thin metal wire, and the wire diameter d is, for example, 0.6 to When it is about 2.5 mm, it is about 2 to 5 mm. Note that the concave / convex pitch of the bent portion can be changed in one thin metal wire, and can be different between the meridian and the latitude. In order to withstand a predetermined filtration pressure, the total amplitude height H is, for example, about 1.5 to 2.2 times the wire diameter d, and has an inclination with an average inclination angle θ of 30 to 80 °. preferable. At this time, the fact that the height H includes 2.0 or less assumes local cross-sectional deformation due to pressurization when forming the bent portion. It should be noted that the pitch of the bent portions can be changed in one thin metal wire, and can be different between meridians and latitudes.
[0025]
The wavy wire 20 is woven with the other metal thin wire, in this example, other wavy wires 20a, which crosses one or more of the bent portions 16, and forms a net-like body.
[0026]
Further, the interval between the metal thin wires intersecting each other to fly the bent portion 16 is 1 or more. In the case of FIG. 3, the two bent portions 16, 16 are skipped between the parallel thin wires. That is, a bent portion adjacent to one intersecting portion of the wavy lines is defined as the first, and the third bent portion 16 intersects with the next other wavy line 20a. The number of the bent portions 16 to be skipped between the parallel thin wires is usually about 2 to 10, and the intersecting pitch is such that the holding strength of the support member 3 is not lowered in consideration of the diameter d of the metal thin wires. In addition, the square of the dashed-dotted line in FIG.
[0027]
Furthermore, the number of skipped bent portions can be the same for both the meridian and the latitude, and can be arranged differently in the line direction or by changing the position. When the interval is different between the meridian and the latitude, the number of supporting points can be reduced without reducing the number of supporting points. This can contribute to weight reduction and flow characteristics.
[0028]
As described above, since the bent portion 16 is woven by being skipped, the weight can be reduced, and a larger number of bent portions can be formed than before, so that the pressure resistance of the wire itself has high characteristics. Therefore, the decrease in the number of bent portions as a whole can be suppressed, the load pressure acting on the bent portions can be reduced, and there is no insertion member as in the metal multilayer filter 1 shown in FIG. Occasionally, indentation on the filter medium can be reduced.
[0029]
Therefore, the number of support parts (the number of convex parts) that directly or indirectly support the filter medium per unit area in the support member is significantly larger than that of the conventional mesh body crossed for each bent part without flying. The number of meridians and latitudes and their intersections can be reduced without reducing the flow, and the flow passage resistance can be reduced by increasing the area of the outflow passage and reducing the fluid flow resistance. . In addition, since the number of use can be substantially reduced, the weight of the filter itself can be reduced, and handling is facilitated.
[0030]
In addition to such a leaf shape, such a support member can be applied to various shapes and types according to various filters such as a plate shape and a cylindrical shape.
[0031]
"Concrete example"
As shown in FIG. 1, a laminated metal filter having a filter medium 2, a support member 3, and an insertion member 4 is used as a filter medium 2, and a sintered body is used in which fine metal fibers of stainless steel are randomly entangled and sintered. The punching plate was used as the insertion member 4. The support member 3 was woven by a crimping machine using wavy lines made of stainless steel having a diameter of 2 mm as meridians 11 and latitude lines 12.
[0032]
The corrugated wire 20 is formed by crimping (uneven corrugation) with a pitch P16 = 3 mm between the bent portions and a height H = 3.8 mm, and the formed wire material thus formed is used as the meridian 11 and the latitude 12. A net product was obtained by crossing and fitting two bent portions 16 every two.
[0033]
As a result, the weight of the support member 3 could be reduced to 30 g. Further, the corrugated wire itself has a high pressure resistance strength, which is the same as that of the conventional product since many uneven portions are formed as in the conventional plain weave mesh. Therefore, the load pressure applied to the convex portion can be reduced, and the generation of indentations on the filter medium can be reduced.
[0034]
A filtration test was performed by attaching 60 sheets of leaf filters 1 in which the outer peripheral edges were melt-bonded to prevent leakage to the filter of the test plant with spacers 10 interposed.
[0035]
The fluid to be treated was a molten polymer of P and P (polypropylene), and the treatment flow rate was 1000 to 1200 kg / hr. The filtration treatment was performed under the conditions described above, and the pressure loss before and after the filtration treatment was measured.
[0036]
As a comparative sample, a filter using a plain weave net product by automatic machine weaving, which has been used as a support member, was also tested and compared at the same time.
[0037]
(Composition of comparison product)
The comparative product was a plain woven net (6 mesh) made of stainless steel wire (wire diameter 2 mm) and formed to a thickness of 4 mm.
[0038]
As a result, the total pressure loss of the invention product was 67.9 kg / mm ² G, which was 10% or more less than that of the comparative product, and there was no deformation or the like with respect to the filtration pressure.
【The invention's effect】
As described above, the laminated metal filter according to the present invention uses a wavy line in which a bent portion is formed in advance as a supporting member, and further, the meridian and the intersection of the parallels are arranged by skipping the bent portion, The number of used filter media can be reduced without reducing the number of filter media support points, and as a result, the outflow characteristics of the fluid to be treated can be improved.
[0040]
In addition, it is possible to reduce the overall weight and to easily remove impurities remaining on the crossing portions of the support members, which have been pointed out in the past. Therefore, the present invention has high reliability, and the present invention has various forms. Industrial applicability is high, such as being applicable to filters.
[Brief description of the drawings]
FIG. 1 is a partial sectional view showing an embodiment of the present invention.
FIG. 2 is a plan view showing an upper half together with a spacer.
FIG. 3 is a plan view illustrating a support member.
FIG. 4 is a cross-sectional view illustrating a support member.
FIG. 5 is an enlarged sectional view showing another embodiment of the filter.
FIG. 6 is a cross-sectional view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laminated metal filter 2 Filter medium 3 Support member 4 Insertion member 11 Meridian line 12 Wet line 14 Concave part 15 Convex part 16 Bending part P16 Concave pitch

Claims (3)

A laminated metal filter formed by laminating a metal filter medium and a support member that directly or indirectly supports the filter medium,
The support member is composed of a meridian using fine metal wires and a mesh-like body woven with latitudes, and at least one of the meridians and latitudes is a wavy line that is shaped in a wavy shape in which concave and convex bent portions are repeated. In addition, the corrugated wire is woven with the other fine metal wire that intersects with one or more of the bent portions. The multilayer metal filter according to claim 1, wherein an insertion member made of a punching plate or a metal powder sintered plate is disposed between the metal filter medium and the support member. The multilayer metal filter according to claim 1, wherein the support member is woven by crimp weaving.

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