JPH059048Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a filter medium support for supporting a filter medium in a polymer filter used in the production of thermoplastic resin films and fibers such as polyester and polyamide.

[Conventional technology]

When extruding molten polymer through a die or die to produce fibers or films, removing foreign matter, gel, etc. from the polymer is an extremely important issue in terms of product quality, and various filters have been developed and used in the past. . As an example, a leaf filter 1 shown in FIG. 6 is known. This leaf filter 1 has the outer periphery of a pair of disc-shaped filter media 2, 2 made of a sintered body of a nonwoven fabric of thin metal fibers fixed by, for example, welding, and supports the filter media 2, 2 inside. 2, a coarse wire mesh 3 for forming a gap 6 between them, and perforated plates 4, 4 are arranged, and a hub ring 5 is attached to the center.
Such leaf filters 1 are stacked using a central hub ring 5 around a polymer discharge pipe (not shown) having a polymer introduction hole on its outer circumferential surface to form a filter unit. The polymer to be filtered enters the cavity 6 in the leaf filter 1 from the outside of the leaf filter 1 through the filter media 2, 2, flows radially inward within the cavity 6, and is removed through the hub ring 5 into the polymer discharge pipe. It can be done. Here, as the wire mesh 3 for forming the void 6, 8 mesh wire mesh (wire diameter 1.2 mm) is usually rolled and flattened to a thickness of about 2 mm.

[The problem that the idea attempts to solve]

However, such leaf filters for polymers have the problem of requiring high filtration pressure.

Passage resistance in the leaf filter includes (a) filtration resistance of the filter medium 2 itself, (b) resistance when the polymer passes through the hub ring, and (c) polymer passing through the filter medium 2 passes through the perforated plate 4 and passes through the wire mesh 3. There are resistances such as . However, when the present inventors confirmed these passing resistances through experiments, they found that the ratio of the above (a), (b), and (c) was 1 to 2:2 to 3:7.
It was found that the resistance due to the wire mesh 3 was extremely large. The reason for this is thought to be that, as shown in Fig. 7, in the wire mesh 3, the passage of the horizontal wire 3a is blocked by the vertical wire 3b, resulting in a small opening ratio (for example, about 20%). . Therefore, reducing the resistance in (c) is effective in reducing the resistance of the leaf filter as a whole.

The present invention was made based on this knowledge, and an object of the present invention is to provide a filter medium support that has lower resistance to polymer passage than conventional wire meshes.

[Means to solve the problem]

The present invention, which was made to achieve the above object, curves a wire having at least two mutually parallel flat surfaces in a wavy manner in a direction perpendicular to the flat surfaces, and curves the wire on a surface parallel to the flat surfaces. The gist is a filter medium support formed by rolling it into a flat plate shape.

Here, the wire constituting the filter media support is as follows:
A flat one with an oval cross-sectional shape is preferable.

〔Example〕

Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 is a schematic sectional view showing a leaf filter 11 using a filter media support according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a part thereof, and FIG. It is a diagram. This leaf filter 1
1 is a pair of disc-shaped filter media 12, 12 made of a sintered body of non-woven fabric of thin metal fibers, sintered metal plates 13, 13 arranged inside the disc-shaped filter media 12, and this sintered metal plate 1.
3, 13, and the sintered metal plates 13, 13
It has a filter medium support 14 for maintaining the filter medium at a predetermined interval, a central hub ring 15, etc., and the outer periphery of the filter medium and sintered metal plate is closed by welding or the like.

The filter medium support 14 has flat surfaces 17a that are vertically parallel to each other, as shown in a cross section and a side view in FIGS. 2 and 3, and as a schematic perspective view of a portion thereof is shown in FIG. A wire 17 having an oval cross section is curved into a wave shape in a direction perpendicular to the flat surface, and the wire is spirally wound on a surface parallel to the flat surface to form a flat plate shape. With this configuration, each vertex 17b of the wavy curved wire 17 is connected to the sintered metal plate 1.
3 and the filter medium 12 outside thereof, the wire valley portion 17c forms a polymer passageway in the leaf filter radial direction. When winding this wire 17 in a spiral, the troughs of radially adjacent wires do not necessarily have to match, and even if they are randomly shifted, a continuous polymer passage in the radial direction is formed, so there is no problem. There is no problem. Further, the wires 17 adjacent to each other in the radial direction may be spaced apart by a suitable distance l as in the illustrated embodiment, or the space may be zero.

The sintered metal plate 13 is used in place of the perforated plate 4 used in the conventional leaf filter 1, but it can be used not only for simply supporting the filter medium 12 but also as a secondary filter. be. When used as a secondary filter, it is preferably a sintered body of metal powder or short metal fibers.
Such a sintered body is effective in crushing and trapping gel in a polymer.

The polymer leaf filter 11 having the above structure is also used in the same manner as the conventional leaf filter 1. That is, the polymer is transferred from the outside of the leaf filter 11 to the filter media 12, 12 and the sintered metal plate 13 inside thereof.
Foreign matter is removed through the leaf filter 11
radially inwardly of the leaf filter through the gap between the sintered metal plates 13, 13 formed by the filter media support 14, and flows into the central hub ring 1.
It is taken out from 5. At this time, in the filter medium support 14 having the above configuration, the valley portions 17c of the wire 17 curved in a wavy manner constitute a polymer passage, but unlike a wire mesh, there is no wire inserted into this space 17c. The aperture ratio is large, so the resistance to polymer passage is reduced compared to a wire mesh, and the filtration pressure can be lowered compared to a conventional leaf filter using a wire mesh. In particular, in this embodiment, since the flat wire 17 with an oval cross section is used, the valley portion 17
Since c can be made large and the end face of the wire is formed of a circular arc, the resistance to the flow of the polymer is extremely small, and the resistance to the passage of the polymer can be further reduced.

In addition, filter media 12, 12 and sintered metal plates 13, 1
The filtration pressure acting on the filter medium support 14 is supported by the filter medium support 14, but the pitch of the apex 17b formed by curving the wire 17 of the filter medium support 14 in a wavy manner is reduced, and the interval between the spirally wound wires is reduced. By reducing the size of the sintered metal plate 13, the sintered metal plate 13 can be supported by an extremely large number of vertices 17b. For example, in the conventional 8-mesh wire mesh 3 (see Figure 6), 1
An inch square is supported by 64 support points, and the wire 17 is 0.5 mm thick and 0.8 mm wide, and the pitch of the apex 17b in the length direction of the wire is 4 mm.
mm, and the pitch of the wire is 1.0 mm, the number of vertices 17b in a 1 inch square is approximately 150,
It can provide support at more points than 8-mesh wire mesh. By forming a large number of vertices 17b on the filter medium support 14 in this way, each apex 1
The support load at 7b can be dispersed to a small extent, and as shown in FIG.
Even if 7c is formed, the strength will not be insufficient and the sintered metal plate 13 can be supported well. Furthermore, since the wire 17 has its flat surface 17a in contact with the sintered metal plate 13 as shown in FIG. 2, it stably supports the sintered metal plate 13 even when subjected to vertical compressive loads. be able to. If a wire 20 with a circular cross section is used, as shown in FIG. 8, when subjected to a compressive load F, there is a risk that it will fall down as shown by the two-dot chain line, resulting in a low compressive load resistance. However, in this embodiment, the flat wire 17
Since this is used, this kind of thing is less likely to occur, and the compressive load resistance can be increased. In addition, if the structure is such that the wavy wire 17 does not fall laterally (that is, in the radial direction of the leaf filter) as shown in FIG.
It is possible to further increase the compressive load resistance,
To achieve this, the radial distance l between the wires may be set to zero (that is, the wires may come into contact with adjacent wires), or the adjacent wires may be welded together at one or more locations on the circumference. It is preferable to fix by brazing or the like.

In general, the sintered metal plate 13 is more easily deformed than conventionally used perforated plates, and when supported by a coarse wire mesh 3, there is a risk of deformation and trouble because there are fewer supporting points. be. However, the filter medium support 14 in this embodiment has far more support points, that is, apexes 17b, than the conventional coarse wire mesh 3, and since the apexes 17b are formed by the flat surface 17a, there is a line contact. Alternatively, since it can be supported by surface contact, it is possible to provide good support even to a thin sintered metal plate. Therefore, in the leaf filter 11 using the filter medium support 14 according to the embodiment of the present invention, the sintered metal plate 13 can be used in place of the perforated plate. The sintered metal plate 13 has less dead space than a perforated plate, so the filter medium 12
This has the advantage that the entire area can be used effectively.

In the present invention, the wire diameter of the wire 17 constituting the filter media support 14, the interval between the vertices 17b formed on the wire 17, the winding density of the wire 17, etc. It may be determined by taking into consideration the number, compressive load to be supported, etc. Here, the winding density of the wire does not need to be uniform throughout, and may be appropriately varied. For example, when the polymer flows from the outer periphery to the inner periphery of the filter media support 14, it is desirable that the resistance at the inner periphery be small, so it is preferable to determine the winding density so that the resistance at the inner periphery is small. Further, by appropriately determining the polymer passage resistance of each part of the filter medium support 14, it is possible to help equalize the flow of the polymer passing through the disc-shaped filter medium 12.

In the above embodiment, a flat wire with an oval cross section was used as the wire 17, but the wire used in the present invention is not limited to this cross section, and has at least two mutually parallel flat surfaces. It is sufficient as long as it has the following. For example, a wire 21 having a rectangular cross section as shown in FIG. 5a, a wire 22 having a rectangular cross section with rounded corners as shown in FIG. 5b, or the like can be used. Further, in the above embodiment, one wire 17 is spirally wound to form the disk-shaped filter medium support 14, but a plurality of wires may be spirally wound to form a disk-shape. A polygonal filter medium support may be obtained by winding a wire into a polygonal shape such as a rectangular shape.

In addition, in FIGS. 1 to 3, the filter medium support 14 of the present invention is used in a leaf filter equipped with a filter medium 12 made of a nonwoven fabric of metal fibers and a sintered metal plate 13, and the sintered metal plate 13 is Although the case where the filter medium 12 is supported through the sintered metal plate is shown, the present invention is not limited to this case, and the type of filter medium supported through the sintered metal plate is arbitrary. Furthermore, the filter medium may be supported through a conventional perforated plate instead of the sintered metal plate, and furthermore, the filter medium may be directly supported as long as the filter medium itself has an appropriate strength. Needless to say.

Further, in the above embodiment, the outer periphery of the pair of filter media 12, 12 is fixed to each other to form a leaf filter that has an integral structure, but the filter media support of the present invention is not limited to this type of filter. It may also be used in a decomposable filter in which filter media are laminated with filter media supports sandwiched between them. Further, although the shape of the filter media support is circular in the drawings, it is not limited to a circle, but may be any shape such as a rectangle or a polygon.

[Effect of idea]

As explained above, the filter medium support of the present invention has a wire having at least two mutually parallel flat surfaces curved in a wave shape in a direction perpendicular to the flat surfaces, and the wire is curved in a wave shape in a direction perpendicular to the flat surfaces. Since it is wound on a surface to form a flat plate, it is possible to stably support the filter medium when filtration pressure is applied to the filter medium supported by this filter medium support, and moreover, it is possible to stably support the filter medium when filtration pressure is applied to the filter medium supported by this filter medium support. This has the effect that the resistance of the polymer can be reduced, and the filtration resistance of the entire filter using this can be reduced.

In addition, the filter media support of the present invention has a large number of support vertices, and each of the vertices supports by line contact or surface contact, so it supports relatively low rigidity materials such as thin metal sintered plates. It is possible to
A metal sintered plate can be used instead of a conventional perforated plate to support the filter medium, increasing the effective area of the filter medium. Furthermore, if a material with appropriate rigidity, such as a sintered metal plate, is used as a filter medium, only that filter medium can be directly supported, which not only expands the effective area of the filter medium but also reduces the overall thickness of the filter. It also has the effect of being able to

Note that if a wire with a flat oval cross section is used as the wire constituting the filter medium support, there is an advantage that the polymer passage resistance can be further reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a leaf filter 11 using a filter media support according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a part thereof, and FIG. 4 is a perspective view schematically showing a part of the filter media support, FIGS. 5a and 5b are sectional views showing modified examples of the wire, and FIG. 6 is a schematic sectional view of a conventional leaf filter. FIG. 7 is an enlarged cross-sectional view of a part of the wire mesh used in the leaf filter, and FIG. 8 is a diagram illustrating the state when a compressive load is applied to the wavy wire 20. 11...Leaf filter, 12...Filtering material, 13
... Sintered metal plate, 14 ... Filter medium support, 17 ...
Wire, 17a...Flat surface, 17b...Vertex, 17
c... Valley part.

Claims (1)

[Claims for Utility Model Registration] (1) A wire having at least two mutually parallel flat surfaces is curved in a wavy manner in a direction perpendicular to the flat surfaces, and the wire is wound on a surface parallel to the flat surfaces. A filter medium support formed in a flat plate shape. (2) The filter medium support according to claim 1, wherein the wire has an oval cross section.