JP2009068133A - Filter for air cleaning, and filter assembly for air cleaning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter for cleaning air, which is used with other filters, prevents the scatter of cut piece dusts of fibers peeling off from the other filters, and is also effective for reinforcing the other filters. <P>SOLUTION: This air-cleaning filter 2 has a laminate disposed with fibers which is obtained by laminating plural fiber arrangement layers by arranging continuous filaments in one direction approximately linearly, and is provided at closer to a space 10 to be air-controlled side than the other filters for cleaning the air, which is installed at the blowing port of an air conditioner. In the fiber arrangement layer, a part of the fiber arrangement layers and the other fiber arrangement layers are laminated in mutually different directions in which fibers are stretched. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air purification filter and an air purification filter assembly, and more particularly to a configuration of an air purification filter.

In facilities that dislike dust, such as food processing factories and semiconductor factories, a filter is often installed at the air outlet of the air conditioning duct to prevent the inflow of dust from the air conditioning system into the room. A filter used for such a purpose is required to have not only excellent particle collection performance but also appropriate air permeability. Conventionally, in order to meet such needs, a filter made of a nonwoven fabric manufactured by a spunbond method or a melt blow method has been widely used (see, for example, Patent Document 1). In order to improve the particle collecting performance, it is necessary to make the gaps between the fibers fine and uniform. Therefore, it has been practiced to reduce the fineness of the fiber and entangle the fiber three-dimensionally. The fibers extending in a random direction while being bent are entangled with each other, so that innumerable voids are formed in the filter, and the particles are efficiently captured.
Japanese Patent Laid-Open No. 2005-238098

  However, since the filter using the conventional nonwoven fabric uses the nonwoven fabric in which the fibers are substantially cut, there is a problem in that the fiber scraps are scattered from the filter surface. That is, since air always flows from the duct toward the air-conditioning target space at the air outlet of the duct, a part of the fibers is peeled off by this air flow and is separated from the filter by riding on the air flow as it is. Will be leaked. The fiber is generally of a fine diameter of about several tens of μm, but may have a serious influence depending on the use of the equipment. In addition, such a filter in which fibers extending in random directions while being bent are entangled with each other generally has a large basis weight (weight per unit area), and the weight of the filter is considerably large depending on the opening size of the outlet. Therefore, the influence on the maintenance inspection work and the influence on the support structure are inevitable.

  In light of the above problems, the present invention provides an air purification filter that is used together with another filter to prevent scattering of the fiber waste that peels from the other filter and is effective for reinforcing the other filter. The purpose is to do. Another object of the present invention is to provide a filter assembly including such an air purification filter and the other filter.

  According to one embodiment of the present invention, an air purification filter has a fiber array laminate formed by laminating a plurality of fiber array layers in which continuous long fibers are arranged substantially linearly in one direction. The air-conditioning target space side is provided with respect to the other air purification filter provided at the air outlet. In the fiber array layer, some fiber array layers and other fiber array layers are laminated in directions in which the fiber drawing directions are different from each other.

  Even if fiber section waste is generated by another air purification filter, the section waste is captured by the air purification filter installed downstream of the other air purification filter. Outflow is prevented. In addition, since the fiber array laminate of the present air purification filter is formed of continuous long fibers, it is difficult for fiber cut waste to be generated. The possibility of itself becoming a source of section waste is very small. Furthermore, since most of the dust is captured by other air purification filters, and this air purification filter mainly needs to capture the fiber waste generated by the other air purification filters, a relatively simple configuration is sufficient. The pressure loss does not increase excessively. Moreover, high rigidity can be obtained with respect to the basis weight by the configuration in which the fiber array layers in which continuous long fibers are arranged substantially linearly in one direction are laminated in directions in which the fiber stretching directions are different from each other. For this reason, it can be effectively used as a reinforcing member for the other air purification filter.

  According to another embodiment of the present invention, an air purification filter assembly includes the above-described air purification filter and the other air purification filter.

  As described above, according to the present invention, an air purifying filter that is used together with another filter, prevents scattering of fiber section waste that separates from the other filter, and is effective for reinforcing the other filter. Can be provided. In addition, according to the present invention, it is possible to provide a filter assembly including such an air purification filter and the other filter.

  Next, the filter and filter assembly of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view of an air conditioning duct in which a filter and a filter assembly of the present invention are incorporated.

  The air conditioning target space 10 is provided with a duct 4 connected to an external air conditioning fan (not shown). In the air-conditioning target space 10, equipment (not shown) that dislikes dust, such as semiconductor manufacturing equipment and food processing equipment, is installed. Air blown from the air conditioning fan passes through the inside of the duct 4 and is sent to the air-conditioning target space 10 from the air outlet 5 that is installed downward at regular intervals along the duct 4. The air staying in the air-conditioning target space 10 is then discharged from the exhaust port (not shown) to the outside of the air-conditioning target space 10 and exhausted to the outside as it is, or through the recirculation line (not shown). To the air-conditioning target space 10 again.

  FIG. 2 is a cross-sectional view of the vicinity of the duct outlet. In the vicinity of the air outlet 5, a first air purification filter (hereinafter referred to as the first filter 1) and a downstream side thereof (that is, the air-conditioning target space 10 side of the first air purification filter) are provided. The second filter for air purification (hereinafter referred to as second filter 2) is arranged in series. The first and second filters 1 and 2 constitute an air purification filter assembly 3. The second filter 2 is installed below the first filter 1 in the vertical direction. The first and second filters 1 and 2 may be supported by a common frame.

  The first air purification filter 1 can be manufactured, for example, by a melt blow method. As will be described later, the manufacturing method of the first air purification filter 1 is different from the manufacturing method of the second filter 2. The fiber layer of the first air purification filter 1 is arranged such that the fibers are bent compared to the fiber array layer of the second filter 2, or the fibers are compared to the fiber array layer of the second filter 2. Although it extends in a random direction, it usually has the characteristics of both. For this reason, a fiber layer in which fibers are intricately entangled three-dimensionally is formed, and very excellent particle collection performance is exhibited. The first air purification filter 1 directly faces the space in the duct 4 and directly collects dust contained in the air from the duct 4 toward the outlet 5. In the figure, the first air purification filter 1 is formed in a box shape, but a folding screen type or other arbitrary shape filter can be used. The surface shape can be flat, bellows or any other surface shape.

  The second filter 2 has a fiber array laminate formed by laminating a plurality of fiber array layers in which continuous long fibers are arranged substantially linearly in one direction. FIG. 3 is an exploded perspective view of the fiber laminate of the second filter. The fiber laminate 11 is formed by laminating a plurality of fiber arrangement layers in which fibers are arranged in one direction. In the figure, four fiber array layers 12A, 12B, 12C, and 12D are shown, but the number of stacked layers can be determined as appropriate according to the application. The fiber array layers 12A, 12B, 12C, and 12D are thermocompression bonded together to form a single fiber laminate 11 as a whole.

  FIG. 4 is an enlarged partial perspective view showing a part of the fiber array layer of the second filter. Only the fiber array layers 12A and 12B are shown in the figure, but the other fiber array layers have the same configuration. As illustrated, the fiber array layer 12A is an aggregate of a large number of fibers 13A extending in parallel and linearly to each other. Similarly, the fiber array layer 12B is an aggregate of a large number of fibers 13B extending in parallel and in a straight line. The fibers 13A and 13B may be folded in the middle or laminated in two or more layers. The fiber array layer 12A can be made from thermoplastic resins such as polyethylene, polypropylene, polyester, polyamide, polyvinyl chloride resin, polyurethane, and fluorine resin, and modified resins thereof. Resins by wet or dry spinning means such as polyvinyl alcohol resins and polyacrylonitrile resins can also be used. The same applies to the fiber array layer 12B. The diameter of each fiber 13A, 13B is, for example, about 10 μm. The fiber array layers 12A and 12B are laminated so that the stretching direction 15A of the fibers 13A of the fiber array layer 12A and the stretching direction 15B of the fibers 13B of the fiber array layer 12B are orthogonal to each other. The stretching direction 15C of the fibers 13C of the fiber array layer 12C is orthogonal to the stretching direction 15B of the fibers 13B of the fiber array layer 12B. Similarly, the extending direction 15D of the fibers 13D of the fiber array layer 12D is orthogonal to the extending direction 15C of the fibers 13C of the fiber array layer 12C. The direction of the fibers in the fiber array layer does not need to be orthogonal to each other between adjacent fiber array layers, and two or more fiber array layers having the same stretching direction may be provided continuously.

  The fibers 13A, 13B, 13C, and 13D of the fiber array layers 12A, 12B, 12C, and 12D do not bend in directions other than the stretching directions 15A, 15B, 15C, and 15D, and do not face random directions. It has extremely high linearity and directionality. Therefore, even if a tensile force is applied in the fiber drawing direction, the fiber is hardly stretched. On the other hand, since almost no resistance force is generated against the tensile force in the direction orthogonal to the fiber stretching direction, when each of the fiber array layers 12A, 12B, 12C, and 12D is provided alone, These fiber array layers are freely deformed. For example, when the fiber array layer 12A is provided alone, it hardly deforms with respect to the tensile force in the stretching direction 15A, but freely deforms with respect to the tensile force in the direction orthogonal to the stretching direction 15A. In the present embodiment, the fiber array layers 12A, 12B, 12C, and 12D are provided by being laminated, and the fibers 13A and 13C of the fiber array layers 12A and 12C are stretched in directions 15A and 15C (hereinafter collectively referred to as a first direction). The fibers 13B and 13D of the fiber array layers 12B and 12D extend in the extending directions 15B and 15D (hereinafter collectively referred to as the second direction S2. The second direction S2 is the first direction). Is perpendicular to S1). Thus, by laminating the fiber array layer so that the fiber drawing directions are orthogonal to each other, a large strength and a restraining force against deformation are generated with respect to a tensile force from any direction. Therefore, by providing the second filter 2 in close contact with the first filter 1, the first filter 1 can be supported from below and function as a reinforcing member for the first filter 1. In addition, since the fibers are arranged in a substantially straight line in one direction in the second filter 2, the bulk thickness is small, maintenance and inspection work is easy, and the influence on the arrangement space is small.

  The fibers of the second filter 2 are substantially free of additives having volatile or bleed out properties at room temperature and processing aids having volatile or bleed out properties. In general, a filter base material itself contains various additives in order to improve spinnability, workability, and stretchability, or a processing aid necessary for each step is added. For example, in a conventional nonwoven fabric, fibers are entangled in a complicated manner, and thus it is necessary to reduce resistance during antistatic or stretching. For these purposes, an additive or processing aid containing oil is used. . However, if these substances are scattered in the air-conditioning target space 10, the atmosphere in the air-conditioning target space 10 may be greatly affected. In particular, when the additive or processing aid contains an oil, the influence is great. On the other hand, in the second filter of the present embodiment, the fibers are arranged linearly in one direction, and the arrangement unevenness is small. Is unnecessary. For this reason, the air which passed the 2nd filter 2 is very clean, and hardly contains the oil content and the piece waste of a fiber.

  The fibers of the second filter 2 are preferably electretized. Thereby, the collection performance can be further enhanced. The electretization can be performed using a known technique such as corona discharge. Additives or processing aids containing oil or the like leak the charge generated by charging due to the hydrophilicity of the oil, but as described above, the fibers of the second filter 2 are such additives and processing aids. Therefore, electretization is effectively performed.

  Next, the manufacturing method of the fiber laminated body of the 2nd filter 2 demonstrated above is demonstrated. FIG. 5 shows a schematic view of a production apparatus used for producing the fiber array layer of the second filter. The fiber array layer manufacturing apparatus 21 includes a spinning unit 22 mainly composed of a meltblown rice 24 and a conveyor 25, and a stretching unit 23 composed of stretching cylinders 26a and 26b, take-up nip rollers 27a and 27b, and the like. ing. The melt blown rice 24 has a large number of nozzles 28 arranged at the tip (lower end) in a direction perpendicular to the paper surface (only one is shown in the figure). A large number of fibers 31 are formed by the molten resin 30 fed from a gear pump (not shown) being extruded from the nozzle 28. Air reservoirs 32a and 32b are provided on both sides of each nozzle 28, respectively. High-pressure heated air heated to a temperature equal to or higher than the melting point of the resin is sent to the air reservoirs 32a and 32b, and is ejected from slits 33a and 33b communicating with the air reservoirs 32a and 32b and opening at the tip of the melt blown die 24. As a result, a high-speed air flow substantially parallel to the extrusion direction of the fibers 31 extruded from the nozzle 28 is generated. The fiber 31 extruded from the nozzle 28 is maintained in a meltable state that can be drafted by the high-speed airflow, and the fiber 31 is drafted by the frictional force of the high-speed airflow, thereby reducing the diameter of the fiber 31. The temperature of the high-speed airflow is set to 80 ° C. or higher, desirably 120 ° C. or higher, than the spinning temperature of the fiber 31. In the method of forming the fiber 31 using the melt blown rice 24, the temperature of the fiber 31 immediately after being extruded from the nozzle 28 can be made sufficiently higher than the melting point of the fiber 31 by increasing the temperature of the high-speed airflow. Therefore, the molecular orientation of the fiber 31 can be reduced.

  A conveyor 25 is disposed below the melt blown rice 24. The conveyor 25 is wound around a conveyor roller 29 and other rollers that are rotated by a drive source (not shown), and the fibers extruded from the nozzles 28 by driving the conveyor 25 by the rotation of the conveyor roller 13. 31 is conveyed rightward in the drawing.

  The fiber 31 flows along a high-speed airflow that is a flow in which high-pressure heated air ejected from the slits 33a and 33b on both sides of the nozzle 28 is merged. The high-speed air current flows in a direction substantially perpendicular to the conveying surface of the conveyor 25 by the high-pressure heated air ejected from the slits 33a and 33b.

  A spray nozzle 35 is provided between the melt blown rice 24 and the conveyor 25. The spray nozzle 35 sprays mist-like water into a high-speed air stream, whereby the fibers 31 are cooled and rapidly solidified. A plurality of spray nozzles 35b are actually installed, but only one is shown in FIG. The fluid ejected from the spray nozzle 35 is not necessarily required to contain moisture or the like as long as the fiber 31 can be cooled, and may be cold air.

  An elliptical airflow vibration mechanism 34 is provided in a region near the melt blown rice 24 where high-speed airflow is generated by the slits 33a and 33b. The airflow vibration mechanism 34 rotates in the direction of the arrow A around an axis 34a that is substantially orthogonal to the conveyance direction D of the fibers 31 on the conveyor 25, that is, substantially parallel to the width direction of the fiber array layer to be manufactured. Be made. In general, when a wall exists in the vicinity of a high-speed jet of gas or liquid, the jet tends to flow near the direction along the wall surface, which is called the Coanda effect. The airflow vibration mechanism 34 changes the flow direction of the fibers 31 using this Coanda effect. In the case of FIG. 5, when the elliptical long axis of the airflow vibration mechanism 34 coincides with the direction of the high-speed airflow (vertical direction in the drawing), the fibers 31 fall almost vertically toward the conveyor 25. When the airflow vibration mechanism 34 rotates 90 degrees around the axis 34a and the elliptical long axis of the airflow vibration mechanism 34 is orthogonal to the direction of the high-speed airflow, the fibers 31 are in the transport direction D (right side in the figure) of the conveyor 25. At this time, the displacement is maximized. When the airflow vibration mechanism 34 further rotates around the shaft 34a, the position where the fibers 31 drop onto the conveyor 25 periodically moves in the front-rear direction with respect to the transport direction D. In other words, the solidified fibers 31 are accumulated on the conveyor 25 while being swung in the vertical direction, and are partially folded in the vertical direction and continuously collected to form continuous long fibers.

  The fibers 31 collected on the conveyor 25 are transported in the transport direction D by the conveyor 25, nipped by the stretching cylinder 26a and the pressing roller 36 heated to the stretching temperature, and transferred to the stretching cylinder 26b. Thereafter, the fiber 31 is nipped between the stretching cylinder 26b and the pressing rubber roller 37, transferred to the stretching cylinder 26b, and is in close contact with the two stretching cylinders 26a and 26b. In this way, the fibers 31 are sent while being in close contact with the drawing cylinders 26a and 26b, so that the fibers 31 become a web in which the adjacent fibers 31 are fused together while being partially folded in the vertical direction.

  The web obtained by being in close contact with the drawing cylinders 26a and 26b is further taken up by take-up nip rollers 27a and 27b (the take-up nip roller 27b in the subsequent stage is made of rubber). The peripheral speed of the take-up nip rollers 27 a and 27 b is larger than the peripheral speed of the stretching cylinders 26 a and 26 b, whereby the web is stretched in the longitudinal direction and becomes the longitudinally stretched fiber array layer 38. In this way, the stretchability of the filaments can be further improved by stretching the spun web in the machine direction. When the fiber 31 is sufficiently quenched, the fiber 31 having a small stretching stress and a high elongation is formed. This is realized by spraying mist-like water from the spray nozzle 35 as described above and including the mist-like liquid in the high-speed airflow. In the fiber array layer formed by the method described above, the directions of the fibers are aligned in one direction.

  As described above, an additive containing oil and a processing aid are not used in each step of manufacturing the fiber array layer. Specifically, when the fiber 31 is extruded from the nozzle 28 (spinning step), no additive or processing aid containing oil is used. Even in the subsequent steps of collection onto the conveyor 25 and fiber drawing, no additive or processing aid containing oil is used. Therefore, the completed second filter 2 does not contain these additives and processing aids.

  The fiber array layered body described above is completed by sequentially laminating and thermocompression-bonding the fiber array layers thus manufactured so that the fiber directions are orthogonal to each other.

  The fiber layer used for the first filter 1 does not need to have fibers arranged in one direction as described above, and may be arranged randomly. Such a fiber layer can be manufactured by a simpler known method. As an example, when the fiber extruded from the melt blown die 24 is dropped as it is without using the airflow vibration mechanism 34 in the above-described process, the fibers are deposited on the conveyor 25 in a random direction. Furthermore, if the fiber web thus formed is welded with a hot roll and recovered without performing the stretching step, the above-described fiber layer can be produced.

It is a schematic perspective view of the air-conditioning duct incorporating the filter and filter assembly of the present invention. It is sectional drawing of the blower outlet vicinity of a duct. It is a partial disassembled perspective view of the fiber arrangement | sequence laminated body which comprises a filter duct. It is a fragmentary perspective view which expands and shows a part of fiber arrangement layer. It is the schematic of the manufacturing apparatus used for preparation of a fiber arrangement | sequence layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st filter 2 2nd filter 3 Filter assembly for air purification 4 Duct 5 Outlet 10 Air-conditioning object space 12A, 12B, 12C, 12D Fiber arrangement layer 13A, 13B, 13C, 13D Fiber 15A, 15B, 15C, 15D Stretching direction 24 Melt blown rice 28 Nozzle 31 Fiber

Claims (6)

An air purification filter having a fiber array laminate formed by laminating a plurality of fiber array layers in which continuous long fibers are arranged substantially linearly in one direction,
It is designed to be provided closer to the air conditioning target space than other air purification filters provided at the air outlet of the air conditioning equipment,
In the fiber array layer, some of the fiber array layers and the other fiber array layers are laminated in directions in which the extending directions of the long fibers are different from each other.
Air purification filter.   2. The air purification filter according to claim 1, wherein the long fiber does not substantially contain an additive having volatile property or bleed-out property and a processing aid having volatile property or bleed-out property.   The air purification filter according to claim 1 or 2, wherein the long fibers are electretized. The air purification filter according to any one of claims 1 to 3,
The other air purification filter;
Have
The air purification filter is provided on the air-conditioning target space side than the other air purification filter,
Air purification filter assembly.   The other air purification filter has a fiber layer in which fibers are bent and arranged compared to the fiber arrangement layer, or the fibers extend in a random direction as compared to the fiber arrangement layer. Item 5. The air purification filter assembly according to Item 4.   The air purification filter assembly according to claim 4 or 5, wherein the air purification filter is a reinforcing member of the other air purification filter.

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