JP3422568B2 - Leaf filter for polymer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer leaf filter which has an improved hub fitting and can be suitably used for filtering a high viscosity fluid such as a polymer.

[0002]

2. Description of the Related Art Filtration technology has been adopted in various fields including various liquids and gases, and the quality of the technology directly or indirectly affects the quality of the final product obtained. The development of various types of filtration devices that meet each of the above characteristics is underway.

For example, in the filtration of a high-viscosity fluid such as a molten polymer, in consideration of heat resistance, corrosion resistance, easiness of regeneration, etc., a metal sintered body obtained by sintering metal fibers, metal powder, etc. is used as a filter medium. Is used, the filtration characteristics,
Specifications such as pore characteristics and thickness are set from the aspect of efficiency.

Further, particularly in the case of the above-mentioned polymer, attempts have been made to improve the structure thereof in order to suppress the generation of a gel-like substance due to the retention during the filtration treatment.
In Japanese Patent Laid-Open No. 31129/1993, in a leaf filter formed by stacking 5 layers in which a mesh material for forming a filter chamber is arranged between a filter material that is hollowed out in a donut shape and a support member that supports the filter material from filtration pressure, In particular, it discloses that a sintered metal is used for the support member in order to suppress the retention between the filter medium and the support member.

On the other hand, in such a leaf filter, it is also necessary to improve the flow resistance of a hub fitting provided at the entrance to the outside of the filtration chamber, and various improvements have been made for this purpose. In Japanese Laid-Open Patent Publication No. 63-73115, as shown in FIG. 4, there is proposed a disc filter mouthpiece 22 in which wire rods 21 are spirally wound around a ring plate 20 at equal intervals.

The present applicant has already filed Japanese Utility Model Application No. 4-7011.
In the invention of No. 5, it is shown that a ring-shaped hub fitting in which a plurality of guide holes communicating from the outer peripheral surface to the inner peripheral surface are formed is used.

[0007]

However, in a filter using such a base or hub fitting,
It cannot be said that the cause of retention during the filtration process has been sufficiently improved, and with the recent trend toward higher quality, the need for even higher precision filters has arisen.

That is, in the former 22 formed by spirally winding the former wire, even if a plurality of openings toward the center are formed by the wire, the substantial openings are of a size formed by the wire pitch. However, there is a problem that a sufficient distribution area cannot be secured, and the winding wire moves with use and the arrangement interval changes.

Further, in the case of winding such two kinds of members, a minute gap is formed at the joint portion between the two members, which easily causes stagnation, and the manufacturing thereof, particularly the winding process of the wire, is very difficult. Therefore, there is a problem that it is unsuitable for mass production and contributes to high cost.

On the other hand, also in the latter hub fitting, it is difficult to reduce the processing cost because it is necessary to provide a large number of guide holes for post-processing, and since it is also a heavy product, the filter itself is easy to handle and the apparatus itself. It is necessary to strengthen.

Further, in such a hub metal fitting, the fluid to be processed around is concentrated in the guide hole, and it becomes clear that there is a factor that causes a stay due to a complicated flow due to the collision of the flows. is there.

Such a retention phenomenon causes a gel-like substance to be generated, which is mixed in the product and causes inconveniences such as stripes and fiber breakage.

In view of these circumstances, the inventor of the present invention adopts a hub fitting in which a twisted wire rod made of a metal strip having a non-circular cross section is formed in a ring shape as a new hub portion structure, so that it is easy to manufacture and has a large number of large pieces. We have completed a filtration device that has an opening and can improve the retention problem.

[0014]

According to the present invention, a porous sintered filter medium, or a pair of filter members formed by combining the filter medium and a support member for supporting the filter medium against the filtration pressure is melted. A spacer for forming a filtration chamber therebetween, and a hub fitting arranged at the mouth of the filtration chamber formed by the inner circumference or the outer peripheral edge which is not fusion-bonded, and the hub fitting is By twist forming a metal strip having a non-circular cross section, a twisting portion that repeatedly forms a convex portion and a concave portion in the length direction is provided on a projection plane parallel to the longitudinal axis of the metal strip material, and the filtering member is supported. It is a polymer leaf filter configured to be substantially formed on an upper portion of a convex portion of the hub fitting.

The invention of claim 2 is the long side d of the metal strip.
Is a polymer leaf filter having a substantially rectangular cross section having a ratio of 2 to 8 times the thickness t, and the invention according to claim 3 is the pitch length in which the convex portion of the hub fitting is formed. (L) is a polymer leaf filter which is 1 to 10 times the long side d of the metal strip and in which a twisted portion is formed for each range of a predetermined length.

[0016]

As described above, in the leaf filter according to the first aspect of the present invention, the hub fitting has the concave portion and the convex portion repeatedly formed along the longitudinal direction by twisting the metal strip having a non-circular cross section. Therefore, the contact between this and the filtering component is made by the convex portion, and both are substantially linear or dot-shaped in a small area. Therefore, it contributes to the suppression of the minute gaps and the retention due to the small gaps in the conventional products that have been conventionally used.

Further, in such a twist-formed hub fitting, the discharge port for the processing fluid formed by the concave portion is formed along the surface of the strip in different spiral directions above and below the strip, and has a large opening. Therefore, the mixing effect can be enhanced and the retention can be further prevented.

Such a hub fitting is not only easy to manufacture and lightweight, but also has a high pressure resistance in terms of structure.

Further, according to the inventions of claims 2 to 3, in addition to the above action, the substantial cross-sectional area of the metal strip is smaller than the circular area drawn by the long side thereof, so that a larger opening is possible. Therefore, the flow-through characteristic can be improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a polymer leaf filter of the present invention (hereinafter referred to as a leaf filter) will be described below with reference to the drawings.

The leaf filter 1 is, as shown in FIG.
A pair of upper and lower filtering members 2 and 2 hollowed out in a donut shape are arranged to face each other and overlap each other, and for example, a welded portion 6 is formed by welding and joining the outer peripheral edges thereof. Further, a spacer 4 is arranged to form the filtration chamber 3 between the filtration members 2 and 2, and in the case where fusion is not performed, a hub fitting 5 is provided at the mouth portion 7 formed on the inner circumference.

In FIG. 2, which is shown by enlarging the direction of arrow A in FIG. 1, the filter member 2 in this example has a fine element a such as metal fiber or metal powder having a predetermined pore characteristic and thickness. A porous sintered metal filter medium 2A formed in
It is constituted by a combination body which is superposed with a supporting member 2B which is located on the downstream side of the filter medium 2A and which directly or indirectly supports the filtration pressure acting on the filter medium 2A.

Further, the filter medium 2A itself may be mixed in addition to the case where it is composed of the single fine element a as described above.
Furthermore, a composite structure in which two or more layers having different physical properties are laminated may be used. Further, as in this embodiment, a rim 2a formed in a U shape by a thin plate may be fitted and reinforced at the mouth portion of the filter medium 2A, that is, the inner peripheral side.

On the other hand, as the supporting member 2B, in addition to the punching plate which has been conventionally used, for example, a sintered metal plate having larger holes than the filter medium 2A, a wire mesh or the like can be used. Further, if the filter medium 2A can withstand the filtration pressure by itself, the supporting member 2B can be omitted, and the filter member 2 can be constituted only by the filter medium 2A.

The mouth of the leaf filter 1 shown in FIG. 1 may be formed on the outer peripheral side, in which case the welded portion 6 is formed on the inner peripheral side.

A spacer 4 and a hub fitting 5 are interposed between the filtration members 2 and 2 to form a filtration chamber 3 and an opening 7 of the filtration chamber 3. As a result, the filtration members 2 are prevented from approaching each other due to the filtration pressure, and the space of the filtration chamber 3 is secured. In this example, the thicknesses of the two are made approximately the same.

As the spacer 4, for example, a wire mesh which has been used up to now (for example, 6 to 20) is used.
#) And the uneven plate with the uneven surface, and the actual flat 1-
The corrugated wire rod according to the proposal of No. 148713 formed in a flat spiral shape can be used.

As shown in FIGS. 1 to 3, the hub fitting 5 is formed by twist-forming a long metal strip 10 having a non-circular cross section so that a projection 5a is formed on a projection plane parallel to the axis of the metal strip 10.
And a concave portion 5b are repeated to form a twisted strip having a twisted portion 5A formed in the lengthwise direction, which is formed by a ring body wound once.

Considering various characteristics such as heat resistance, corrosion resistance, and strength, the metal strip 10 is made of, for example, stainless steel, nickel, chromium, or other metal alloys.
In particular, the stainless steel is preferable because it is excellent in pressure resistance due to work hardening by twisting.

As the metal strip 10 for the hub fitting 5, a continuous strip having a long side d and a predetermined thickness t is used in this example, and more preferably a long side d and a thickness t. It is also possible to set the dimensional ratio of 2 to 8 and to make the ridge part, for example, a sharp edge in order to make the contact surface with the filter member 2 in contact therewith smaller, for example, 0.2 to 0.5 mmR.
As a round surface to some extent, it can also serve to suppress the retention of untreated fluid.

When the dimensional ratio is less than 2, a large flow hole is not formed due to various twists, and the flow resistance of the processing fluid increases. On the contrary, when it exceeds 8 times, the pressure resistance decreases. However, the product is thicker than necessary, and more preferably about 2.5 to 5 times.

Further, by setting the cross-sectional area of the metal strip 10 to be about 1/3 to 1/10 times the circular area drawn by the long side d, a large flow path and sufficient pressure resistance can be obtained. Can be For example, elliptical cross section,
It is possible to employ a polygonal shape (for example, a star shape) curved in a concave shape toward the axis.

By twist forming using such a metal strip 10, as described above, the twisted portion 5A in which the projection 5a and the recess 5b are repeated in the lengthwise direction on the projection plane parallel to the axis Y thereof. Is formed as a twisted strip. Therefore, the contact with the filter member 2 is made only by the convex streak portion 5a, and the contact between the two becomes a line or point contact, which is effective in preventing retention and gelation.

Further, in this case, the concave portion 5b forms a substantial flow hole 5c. In this case, in order to further improve the flow resistance of the processing fluid, for example, on the side surface of the thickness of the strip 10. It is also possible to use a material having irregularities formed in advance or a material having auxiliary holes 8 as shown in FIG. 2 provided at predetermined intervals.

The twisted portions 5A may be provided continuously over the entire length thereof, may be provided intermittently only with an arbitrary length, and further, as shown in FIG.
Various modes are possible such as twisting rotation at every 90 °, and in particular, in the latter twisting rotation at every 90 °, the concave portion 5b is longer than the length of the convex portion 5a so as not to obstruct the flow of the fluid to be treated. It is preferable to make it long.

Further, in the present invention, the pitch length L at which the convex portion 5 is formed is preferably the length of the metal strip 10 constituting the pitch length L in view of the relationship between the flow resistance of the fluid to be treated and the pressure resistance. About 1 to 10 times (more preferably about 1.5 to 5 times) the side d, and if necessary, the twist may change the pitch for each position in the filter, or 2 as described above.
The above twists may be mixed.

In particular, since the hub metal fitting 5 arranged at the mouth portion 7 of the filtration chamber 3 concentrates a large amount of the processing fluid processed by the filtration member 2, the pressure loss tends to increase and the hub metal 5 can be pressed lower. At that portion, the pitch length L of the convex portion 5a and the winding pitch may be formed larger than those of other portions.

The applicant of the present invention, as a hub fitting suitable for this example, uses a stainless steel strip (width 4 mm, thickness 1.5 mm,
The width of 6 mm and the thickness of 1 mm) was subjected to a filtration test on each of the test pieces having a convex interval of 4 to 10 mm which was formed by twisting under the above-mentioned several conditions. However, gel generation was reduced and no trouble occurred. It was

By such twisting, the twisted portion 5A is formed in the hub metal fitting 5 along the longitudinal direction thereof, and therefore the contact area with the filter member 2 in contact with this is greatly reduced. It will be.

On the other hand, in the concave portion 5b, the processing fluid flow port 5c is formed along the spiral surface of different directions above and below due to the twisting, whereby the processing fluid is disturbed and mixed. The effect can be enhanced and retention can be suppressed.

The hub metal fitting 5 formed in this way has one
It is possible to use a ring body having only strips, or a plurality of windings of two or more, and the spacer can also be substituted by continuous winding of the hub fitting, and the hub fitting 5 can be used as the spacer 4 and the supporting member 2B. It is also possible to use it by spot-bonding it with.

[0042]

As described above, the polymer leaf filter of the present invention is particularly one in which the opportunity for residence in the filtration of the polymer is suppressed by improving the hub fitting, and the pressure resistance is also increased. In addition, it is possible to improve the filtration efficiency and to provide a high-purity product.

[Brief description of drawings]

FIG. 1 is a cross-sectional perspective view illustrating a polymer leaf filter of the present invention.

FIG. 2 is an enlarged partial view as seen from the direction of arrow A in FIG.

FIG. 3 is a front view showing another example of the hub fitting.

FIG. 4 is a perspective view showing a conventional hub fitting.

[Explanation of symbols]

1 Leaf filter 2 Filter member 3 filtration chambers 4 spacers 5 Hub bracket 5A twist part 5a convex part 6 connection 10 Metal strip Y axis core

Claims (3)

(57) [Claims] 1. A porous sintered filter medium, or a pair of filter members formed by combining the filter medium and a supporting member for supporting the filter medium against filtration pressure, are melt-bonded to the inner or outer peripheral portions thereof, and a filter chamber is provided therebetween. And a hub metal fitting arranged at the mouth of the filtration chamber formed by the inner circumference or the outer peripheral edge which is not fusion-bonded, and the hub metal fitting is a metal strip having a non-circular cross section. Twisting forming a twisting portion for repeatedly forming a convex portion and a concave portion in the length direction on a projection plane parallel to the longitudinal axis thereof, and supporting the filtering member above the convex portion of the hub fitting. A polymer leaf filter configured substantially as described above. 2. The long side d of the metal strip has a thickness t of 2-8.
The polymer leaf filter according to claim 1, wherein the polymer leaf filter has a substantially rectangular cross-section having a double ratio. 3. The pitch length (L) at which the convex portion of the hub fitting is formed is 1 to 10 times the long side d of the metal strip,
The polymer leaf filter according to claim 1 or 2, wherein a twisted portion is formed for each range of a predetermined length.