Filter structure

Abstract

To solve the problem that when an output end of a pleat filter for polymer filtration is fixed in an enclosure by swaging, the output end cannot filter a polymer sufficiently, and the problem that a polymer may accumulate and discolor and a foreign matter may occur.SOLUTION: A filter structure according to the present invention, which filters high-viscosity fluid, comprises an enclosure 1 and a first filter 2 and a second filter 3 provided in the enclosure 1, in which a position of an end part at an output side for fluid of the second filter 3 is moved to the opposite side with respect to an output end for fluid in the enclosure 1.EFFECT: The position of the end part at the output side for fluid of the second filter 3 is arranged at a middle position of a flow passage, which can nearly dissolve accumulation of fluid at the position of the end part. This can solve the problem that the output end cannot filter resin sufficiently, so it is possible to solve the problem that the resin may accumulate and discolor and a foreign matter may occur.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filter structure that can improve the yield of filtering of highly viscous resins. [Background technology]

[0002] There are many types of fluid filtration filters, including tube filters with numerous holes that run coaxially through the inner and outer periphery of the housing, and pleated filters made of metal fibers with peaks folded in the outer diameter direction and valleys folded in the axial direction that are continuous in the circumferential direction.

[0003] For example, Patent Document 1 (JP Patent Publication No. 10-113507) comprises a cylindrical water collection core with a large number of water passage holes formed in the peripheral wall, and a pleated filter body (pleated filter) formed by folding a flat filter sheet arranged on the outer periphery of this water collection core into pleats in the radial direction to form a cylindrical shape, and a cylindrical activated carbon fiber filter material is arranged on the outer periphery of the pleated filter, and the activated carbon fiber filter material and the pleated filter form a two-layer composite filtration structure.

[0004] The filter in Patent Document 1 is designed to filter water, and cannot be used to remove impurities from highly viscous resins, such as molten resins, which is the application of the present invention. The reason for this is that resins have high viscosity, so high pressure is applied to force the resin through the filter, but in structures such as Patent Document 1 where the pleated filter has the same diameter at the input and output ends, the high pressure at the output end of the pleated filter will cause damage.

[0005] Therefore, pleated filters for resin filtration are narrowed so that the tip end of the output end has a small diameter, and the narrowed tip diameter part of this pleated filter is crimped between the inner surface of the housing, which serves as a container for the resin that covers the entire filter, and the outer surface of the water collection core referred to in Patent Document 1.

[0006] However, when the output end of a pleated filter is fixed inside a housing by crimping as described above, the crimped portion of the output end inside the housing has an irregular shape, making filtration impossible and causing high-temperature resin to accumulate at the output end. This accumulation of resin can cause discoloration or denaturation into foreign matter, which can then be mixed into the resin and reduce the quality of the resin after filtration. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-113507 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem that this invention aims to solve is that in pleated filters used to filter high-temperature, high-viscosity resins at high pressure, the output end is fixed inside the housing by crimping, which results in insufficient filtration of resin at the output end, as well as retention, discoloration, and the generation of foreign matter. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a filter structure for filtering highly viscous fluids, comprising a housing, and a first filter and a second filter provided within the housing, and the end position of the fluid output side of the second filter is moved to the opposite side of the fluid output end of the housing. [Effects of the Invention]

[0010] With the above-described structure, the resin that tends to accumulate at the output end of the second filter is located midway between the output end of the second filter and the output end inside the housing, and is therefore reliably filtered and allowed to flow toward the output end by the delivery pressure of the subsequent resin. As a result, discoloration of the resin that accumulates at the output end and generation of foreign matter can be prevented. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a filter structure of the present invention. [Figure 2] 1 is a cross-sectional view showing only a filter portion in a filter structure of the present invention. [Figure 3] FIG. 10 is a cross-sectional view showing only a filter portion according to another example of the filter structure of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention solves the problems of insufficient filtration of resin at the crimped portion of the output end, which is caused by crimping the output end of a pleated filter for resin filtration, and of resin accumulating at the crimped portion, causing discoloration, or being transformed and generating foreign matter, by providing a housing and a first filter and a second filter provided within the housing, and by moving the end position of the second filter on the fluid output side to the opposite side from the fluid output end of the housing.

[0013] The filter structure of the present invention is used, for example, for filtering high-viscosity, high-temperature resin. When filtering high-viscosity, high-temperature resin, the structure must be able to withstand the high pressure required to pump the resin to the output side due to its high viscosity, and the high temperature requires the use of a material that will not be altered by heat.

[0014] In addition to the above, when filtering high-viscosity, high-temperature resin, new conditions must be met: it is not permitted to have any areas where the viscous resin can stagnate, and it is not permitted to have any areas throughout the filtering component that will be damaged or break down due to being unable to withstand the high pressure of the resin being fed.

[0015] In consideration of the above, in the present invention, it is preferable that the housing, the first filter, and the second filter are made of stainless steel, which is not denatured at high temperatures and has excellent corrosion resistance. Then, the resin pumped from the input port formed in the housing passes through the outer periphery (large diameter) of the internal space of the housing, the second filter, and the second and first filters, forming a flow path toward the output port of the housing.

[0016] In the above-described flow path, the second filter is preferably a pleated filter in which a flat filter sheet is folded radially into pleats and wound around the outer periphery of a punched cylindrical core, and the first filter is preferably a tube filter in which the pleated filters share a common internal flow path.

[0017] If the second filter is a pleated filter, the ends are folded to reduce the diameter in order to allow the resin to flow into the pleated filter. However, this time the reduced diameter part may not be able to withstand the pressure of the resin and may break, and there is also a possibility that resin may accumulate in this part.

[0018] Therefore, in the present invention, the output end position of the pleated filter, which is the second filter, is moved to the opposite side of the resin output end in the housing. In this way, the output end position of the resin of this second filter is not located at the output end in the resin flow path, so it is avoided from receiving all of the resin pressure as an output end. As a result, damage to the second filter can be prevented and resin retention can be suppressed.

[0019] Furthermore, in the present invention, when the first filter is a tube filter, it may be provided from the end position of the output side of the second filter to the output end of the resin in the housing. In this way, the end position of the output side of the resin in the second filter can be moved to the opposite side of the output end of the resin in the housing, thereby preventing insufficient filtration up to the output end of the housing.

[0020] In the present invention, various types of structures can be considered for moving the end position of the output side of the resin of the second filter to the opposite side of the output end of the resin in the housing, including the configurations of the first filter and the second filter. The various types can be broadly divided into two types: for example, as described above, the type in which the end position of the output side is moved, and the other type in which the output end of the resin extends (protrudes) from the end position of the output side of the resin of the second filter. In either case, the relative positional relationship between the "end position" of the output side of the resin of the second filter and the "output end" of the resin in the housing remains unchanged. [Example]

[0021] Specific embodiments of the filter structure of the present invention will be described below with reference to the drawings. In this example, the resin filtered by the filter structure of the present invention is a high-temperature, high-viscosity resin. This resin has high viscosity and low fluidity, so it passes through the filter structure of the present invention under high pressure.

[0022] In this example, the filter structure mainly comprises a housing 1 having a filtration space P formed therein, a first filter 2, and a second filter 3, and is characterized in that the output end 3A of the resin of the second filter 3 is moved to the opposite side of the output end 1A of the resin in the housing 1.

[0023] Specifically, in this example, a tube filter is provided on the input side of the filtration space P of the housing 1 as the second filter 3, and a tube filter is provided on the output side as the first filter 2. In other words, in this example, the first filter 2 is connected to the output end of the second filter 3, so that the end 3A of the resin on the output side of the second filter 3 is moved to the opposite side of the output end 1A of the resin in the housing 1.

[0024] The first filter 2 comprises a punched cylindrical core 2A and a mesh filter 2B wound around the core 2A. In this example, the mesh filter 2B may be made of metal fiber instead of a mesh material formed by stacking and diffusion-bonding multiple metal wire meshes. The second filter 3 comprises a punched cylindrical core 3A and a pleated filter 3B, which is made of metal fiber and has circumferentially continuous peaks folded in the radial direction and valleys folded in the axial direction, wrapped around the core 3A. The pleated filter 3B may also be made of the mesh material instead of a metal fiber.

[0025] In this example, the second filter 3 has a crimped portion 3C formed at the output end of the pleated filter body 3B, in which the peaks are each folded along the circumferential surface (of the core body 3A) in the direction in which the diameter of the valleys is reduced, and are crimped around the core body 3A.

[0026] The output end of the second filter 3 and the input end of the first filter 2 are connected by, for example, welding via a ring R having the same diameter as the core body 3A and the core body 2A.

[0027] In addition, a cap 2a is provided at the input end of the second filter 3 to prevent the resin input into the housing 1 from flowing into the core body 3A, and to allow the resin to flow into the core body 3A from the outer periphery of the pleated filter body 3B.

[0028] The operation and effects of the filter structure configured as above will be explained below. When resin flows into the filtering space P from the input end inside the housing 1, it is urged by the cap 2a toward the outer periphery of the second filter 3. As the filling amount in the filtering space P increases and the internal pressure rises, the resin is filtered by the outer surface of the pleated filter body 3B, penetrates into the core body 3A, and flows toward the output side.

[0029] The resin is pumped through the filtering space P in the housing 1 to the output side, but by positioning the output end of the second filter 3 midway through the entire filtering flow path of the resin, the inner diameter of the filtering space P is narrowed at the crimped portion 3A compared to a structure in which it was previously located at the output end, which promotes the flow of resin into the core body 3A, thereby improving the filtering efficiency of the pleated filter body 3B.

[0030] Furthermore, by locating the output end position of the second filter 3 midway through the entire resin filtration flow path, the flow path does not completely terminate at the crimped portion 3A, which almost completely eliminates resin stagnation at the crimped portion 3A. Furthermore, as mentioned above, the resin flow pressure does not concentrate in the output direction at the crimped portion 3A, which results in preventing damage to the crimped portion 3A.

[0031] In other words, according to the filter structure of the present invention, by moving the end position of the fluid output side of the second filter 3 to the opposite side of the fluid output end in the housing 1, the above effect can be achieved, thereby improving the problem of insufficient filtration of resin at the output end, which can cause stagnation and discoloration or the generation of foreign matter.

[0032] In the above embodiment, to put it simply, the first filter 2 is connected to the output side of the second filter 3, and the end position of the fluid output side of the second filter 3 is moved to the opposite side of the fluid output end in the housing 1, but instead, a configuration as shown in Figure 3 may be used.

[0033] The first filter 2 in the filter structure shown in Fig. 3 is configured as a single core body 12A formed by integrating the core body 3A and the core body 2A via the ring R shown in Fig. 1 and Fig. 2, and a mesh filter body 2B is wound around this core body 12A on the output side of the ring R. Note that the ring R does not have to be a separate body, and an unpunched portion may be formed in a single tube.

[0034] On the other hand, the second filter 3 in the filter structure shown in FIG. 3 is configured such that a pleated filter body 3B is wound on the input side of the ring R (the non-punched area surrounded by the dashed line) of the core body 12A, and a crimped portion 3C is formed at the output side end of the pleated filter body 3B.

[0035] 3, the first filter 2 is composed of a core body 12A and a mesh filter body 2B, and the second filter 3 is composed of a pleated filter body 3B. In short, the mesh filter body 2B is wound on the output side of a single core body 12A, with the ring R as the boundary, and the pleated filter body 3B is wound on the input side.

[0036] 3, the output end of the second filter 3 protrudes from the first filter 2, thereby shifting the position of the end of the fluid output side of the second filter 3 to the opposite side of the fluid output end in the housing 1. Even with this filter structure, it is possible to obtain the same effects as those described above.

[0037] In short, the filter structure of the present invention is one in which the output side end position of the second filter 3 has been moved to the opposite side of the resin output end (output port position) in the housing 1, and may be either a structure in which the output end of the first filter 2 protrudes from the output side end of the second filter 3, or a structure in which the output side end of the second filter 3 has been moved from the output end of the first filter 2. [Explanation of symbols]

[0038] P Filtration space 1 chassis 2. First filter 2B mesh filter 3 Second filter 3B pleated filter body 3C Crimping section (end position on the output side of the second filter)

Claims

[Claim 1] A filter structure for filtering a highly viscous fluid, comprising a housing, and a first filter and a second filter provided within the housing, wherein the end position of the fluid output side of the second filter is moved to the opposite side of the fluid output end of the housing.

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