Filter pack and air filter including the same

Abstract

[Problem] To provide a filter assembly and air filter that can suppress the rise in pressure loss while appropriately maintaining the pleat interval. [Solution] The filter material comprises: a filter media and a plurality of spacer members. The filter media has: alternating pleats on the upstream and downstream sides of the airflow caused by pleating; at least one pair of upstream ventilation surfaces through which airflow enters via the pleats on the downstream side; and at least one pair of downstream ventilation surfaces through which airflow exits via the pleats on the upstream side. The plurality of spacer members are formed on each upstream ventilation surface and each downstream ventilation surface to maintain the spacing between each pair of upstream ventilation surfaces and each pair of downstream ventilation surfaces. The plurality of spacer members formed on the upstream ventilation surfaces are intermittently formed in a direction orthogonal to the pleats, and at least one spacer member formed on one pair of upstream ventilation surfaces contacts at least two points with at least one spacer member formed on another pair of upstream ventilation surfaces.

Description

[Technical Field]

[0001] The present invention relates to a filter assembly having a filter material that has been pleated and an air filter having the same assembly. [Previous Technology]

[0002] Filter assemblies are known in the past that have spacer-holding members formed on the pleated filter material to maintain the pleat spacing equally. For example, Patent Document 1 discloses a filter assembly in which the spacing is maintained by the opposing spacer-holding members contacting each other. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-062610 [Summary of the Invention]

[0004] [The problem the invention aims to solve]

[0005] The spacer retaining member is a component that maintains the pleat spacing of the filter assembly, thereby increasing pressure loss by covering the ventilation surface of the filter media. Furthermore, in order for the spacer retaining members to contact each other, if the positional and dimensional accuracy of the spacer retaining members during formation and pleat processing cannot be obtained, the spacer retaining members will not be able to contact each other, resulting in concerns that the pleat spacing cannot be maintained evenly.

[0006] This invention was made in consideration of such a situation, and its object is to provide a filter assembly that can appropriately maintain the pleat spacing while suppressing the increase in pressure loss, and an air filter having the same assembly. [Technical Means for Solving the Problem]

[0007] The filter assembly of the present invention, in order to solve the above-mentioned problems, comprises: a filter material for capturing microparticles in a gas, and having: pleats that are alternately repeated on the upstream and downstream sides of the airflow by pleating; at least one pair of upstream ventilation surfaces through which the airflow flows in, with the aforementioned pleats on the downstream side facing each other; and at least one pair of downstream ventilation surfaces through which the airflow flows out, with the aforementioned pleats on the upstream side facing each other; and a plurality of spacer members formed on each of the aforementioned upstream ventilation surfaces and each of the aforementioned downstream ventilation surfaces to maintain the spacing between each of the aforementioned pairs of upstream ventilation surfaces and each of the aforementioned pairs of downstream ventilation surfaces. The plurality of spacer members formed on the aforementioned upstream ventilation surfaces are intermittently formed in a direction orthogonal to the aforementioned pleats, and at least one pair of spacer members formed on one of the aforementioned pairs of upstream ventilation surfaces and at least one pair of spacer members formed on the other of the aforementioned pairs of upstream ventilation surfaces are in contact at two or more locations. [Effects of the Invention]

[0008] In the filter assembly and air filter of the present invention, the pleat interval can be appropriately maintained while suppressing the increase of pressure loss.

Implementation Method

[0010] The following figures illustrate embodiments of the filter assembly and air filter of the present invention. Figure 1 shows a perspective view of an air filter 1 as one embodiment of the air filter of the present invention. Figure 2 shows a portion of the folded filter assembly 3 viewed from above, with the pleats 12 and 13 extending in the direction of extension. Figure 3 is a partial enlarged view of Figure 2.

[0011] The air filter 1 includes a filter assembly 3 and a frame 5. The frame 5 surrounds the filter assembly 3, and the creases 12 and 13 of the filter media 11 of the filter assembly 3 are arranged on the upstream and downstream sides in the airflow direction (X direction) through the filter media 11. Furthermore, for convenience in this embodiment, the crease located on the upstream side (-X direction) of the airflow is referred to as crease 12, and the crease located in the downstream direction (+X direction) of the airflow is referred to as crease 13. The filter assembly 3 includes filter media 11 and a plurality of spaced retaining members 20.

[0012] The filter media 11 is a component for capturing microparticles in a gas. The filter media 11 is, for example, used for removing dust particles with a diameter of 2.5 μm or less and a concentration of 0.3 mg / m³ or less. The filter media 11 has, for example, a capture efficiency of 80% or more, a pressure loss of 79 to 493 Pa, and a dust retention capacity (dust holding capacity) of 200 to 800 g / m², as measured by a counting method. In the counting method, the measurement is performed by ventilating air containing any one of the following particles: atmospheric dust, polyalphaolefin (PAO), or silica with a diameter of 0.3 μm. The dust retention capacity is the amount of dust captured by the filter until a predetermined final pressure loss is reached. Furthermore, the filter media 11 can also be, for example, filter media for HEPA filters, filter media for ULPA filters, or filter media for gas removal filters.

[0013] The filter material 11 is, for example, glass fiber, organic fiber, or a fibrous body formed from a mixture of such fibers, such as nonwoven fabric or felt. The filter material 11 formed from glass fiber is manufactured, for example, by wet or dry papermaking. The filter material 11 formed from organic fiber is manufactured, for example, by spunbonding, meltblowing, thermal bonding, chemical bonding, etc. Furthermore, the filter material 11 may also be, for example, a laminate of multiple nonwoven fabrics with different collection efficiencies.

[0014] The filter material 11 is pleated into a roughly V-shape by alternating mountain and valley pleats. The pleating is performed using a reciprocating or rotary pleating machine. By being pleated, the filter material 11 has parallel pleats 12 and 13 on the upstream and downstream sides of the airflow. Furthermore, the filter material 11 has a plurality of pairs of ventilation surfaces 14 (ventilation surfaces 14a and 14b) that are continuous via the pleats 12 and 13 and are opposed in the roughly Y direction.

[0015] Specifically, the ventilation surface 14 has: a plurality of (at least one set) pairs of upstream ventilation surfaces 15a, 15b and a pair of downstream ventilation surfaces 16a, 16b. The pair of upstream ventilation surfaces 15a, 15b are ventilation surfaces 14 through which airflow flows in opposite directions via the fold 13 on the downstream side. The pair of downstream ventilation surfaces 16a, 16b are ventilation surfaces 14 through which airflow flows out opposite directions via the fold 12 on the upstream side. Hereinafter, without distinguishing between the upstream ventilation surfaces 15a, 15b and the downstream ventilation surfaces 16a, 16b, they will simply be referred to as ventilation surface 14.

[0016] The spacer retaining member 20 is a plurality of members that retain the space (pleat space) between a pair of ventilation surfaces 14 set on the filter material 11. The spacer retaining member 20 is intermittently formed on the ventilation surface 14 in a direction orthogonal to the direction along the pleats 12, 13 (approximately the X direction). In Figure 2, for example, three spacer retaining members 20 are intermittently formed on the ventilation surface 14a.

[0017] At least one spacer retaining member 20 formed on one of a pair of ventilation surfaces 14 makes contact with at least one spacer retaining member 20 formed on the other pair of ventilation surfaces 14 at more than two locations. Specifically, the spacer retaining member 20a formed on the ventilation surface 14b makes contact with the contact points 23, 23 of the adjacent plurality of spacer retaining members 20b, 20c formed on the ventilation surface 14a at two locations.

[0018] The spacer retaining member 20 formed on one of a pair of ventilation surfaces 14 has opposing surfaces 25 relative to the spacer retaining member 20 formed on the other pair of ventilation surfaces 14. The opposing surfaces 25 are, for example, flat front ends of the spacer retaining member 20. As shown in FIG3, the opposing surface 25a of the spacer retaining member 20a formed on the ventilation surface 14b contacts the opposing surfaces 25b, 25c of the spacer retaining members 20b, 20c formed on the ventilation surface 14a, and ideally the sum of the lengths d1, d2 along the approximately X direction is between 1% and 10% of the length D of the opposing surface 25a along the approximately X direction. If it is less than 1%, there is a concern that the spacer retaining effect will decrease due to the small contact area 23. If it is greater than 10%, the size of the spacer retaining member 20 increases, the area covering the ventilation surface 14 increases, and the pressure loss during filter use increases.

[0019] Furthermore, the spacing retaining member 20 has different heights (approximately Y-direction length) depending on the pleat spacing. Specifically, in FIG2, the pleat spacing between a pair of ventilation surfaces 14a, 14b increases from crease 12 toward crease 13, so the height of the spacing retaining member 20 on the crease 12 side is small, and the height of the spacing retaining member 20 on the crease 13 side is large.

[0020] The spacer retaining member 20 is formed, for example, of a thermoplastic resin called a hot melt adhesive. Examples of such thermoplastic resins include polyamide-based, urethane-based, or olefin-based thermoplastic resins. The spacer retaining member 20 is formed, for example, by directly applying the hot melt adhesive to the filter material 11 in the general X direction using a gun filled with softened hot melt adhesive. Alternatively, the spacer retaining member 20 can be formed by, for example, attaching a cured hot melt adhesive to the filter material 11, in addition to direct application. Furthermore, the spacer retaining member 20 can also be made of other materials such as ceramic.

[0021] In such an air filter 1 and filter assembly 3, the spacer retaining members 20 formed on one pair of ventilation surfaces 14 of one side are in contact with each other at two points relative to the spacer retaining members 20 formed on the other pair of ventilation surfaces 14. Therefore, compared to the case where they are in contact at only one point, the filter assembly 3 is more likely to maintain the pleat spacing. That is, when the spacer retaining members 20 are in contact at only one point, for example, if the positions of the spacer retaining members 20 on each of the pair of ventilation surfaces 14 are deviated due to manufacturing errors, they may not be in contact. In this case, the pleat spacing cannot be maintained, which raises concerns about low filtration efficiency.

[0022] In contrast, in this embodiment, the air filter 1 and filter assembly 3 are in contact at two points, so the opposing spacer retaining members 20 can reliably contact each other and are supported at two points. Furthermore, due to friction and other effects at the contact points 23, there is also the advantage that the spacer retaining members 20 are less likely to shift. Therefore, such a filter assembly 3 and air filter 1 can suppress the increase in pressure loss while appropriately maintaining the pleat spacing.

[0023] Although several embodiments have been described in this invention, these embodiments are merely examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are also included within the scope of the invention described in the claims and its equivalents.

[0024] For example, in the filter assembly 3, it is illustrated that the spacer retaining member 20 formed on one pair of ventilation surfaces 14 contacts an adjacent plurality of spacer retaining members 20 formed on another pair of ventilation surfaces 14 at one point. However, it is also possible for one spacer retaining member 20 formed on one pair of ventilation surfaces 14 to contact another spacer retaining member 20 formed on another pair of ventilation surfaces 14 at multiple points. For example, in the first modified example shown in FIG4, one spacer retaining member 20d formed on the other pair of ventilation surfaces 14d has two convex shapes 26 protruding in the height direction. The spacer retaining member 20e formed on one pair of ventilation surfaces 14e contacts at two points by contacting the two convex shapes 26. Furthermore, there may be more than two contact points 23.

[0025] Furthermore, in the second variation shown in FIG5, among the spacer retaining members 20 formed on a pair of ventilation surfaces 14f, 14g, the spacer retaining member 20f formed on one of the ventilation surfaces 14f can also be provided as a point (approximately hemispherical) with a short length in the approximately X direction. In this case, the spacer retaining member 20g formed on the other ventilation surface 14g and two or more adjacent opposing spacer retaining members 20f make contact at two or more points. As shown in FIG4 and FIG5, in the filter assembly, as long as at least one spacer retaining member 20d, 20f formed on one of the ventilation surfaces 14e, 14g is supported at two points on the other ventilation surface 14d, 14f, the other spacer retaining member 20d, 20f being supported at one point can also be included within the scope of the filter assembly of the present invention.

[0026] It is also explained that in the filter assembly 3, even on any of the upstream ventilation surfaces 15a, 15b and the downstream ventilation surfaces 16a, 16b, the spacer retaining member 20 is intermittently formed in the generally X direction. However, in the downstream ventilation surfaces 16a, 16b, the spacer retaining member 20 may also be continuously formed in the generally X direction.

[0027] Hereinafter, FIG6 is a filter assembly 103 as a third variation, and is a diagram showing a portion of the folded filter assembly 103 viewed in the direction of the elongation of the pleat crease. Furthermore, in FIG6 and FIG7, the same reference numerals are used to denote the structures and parts corresponding to the filter assembly 3, and repeated descriptions are omitted.

[0028] The filter assembly 103 differs from the filter assembly 3 in that the spacer members 120b formed on the downstream ventilation surfaces 116a, 116b are not intermittent in the generally X direction, but are formed continuously. That is, adjacent spacer members 120b in the generally X direction are formed in close contact without forming gaps.

[0029] For example, when continuous ventilation is performed on the filter assembly 103, there are concerns about changes in the internal structure even if there is no apparent change in the appearance of the filter assembly 103. For example, there are concerns that the pleat spacing between the pair of upstream ventilation surfaces 115a and 115b of the filter assembly 103 may increase as the incoming airflow bulges outward toward the outflow side.

[0030] Herein, the filter assembly 103, based on the advantage of the filter assembly 3 in suppressing the rise of pressure loss, forms spacer members 120a and 120b to increase the strength of the filter material 11. That is, the spacer members 120a formed on the upstream ventilation surfaces 115a and 115b are formed intermittently in the generally X direction, and the spacer members 120b formed on the downstream ventilation surfaces 116a and 116b are formed continuously in the generally X direction. The spacer members 120b are the opposing surfaces 125 of the spacer members 120b that are in contact with the upright 121 of the downstream ventilation surfaces 116a and 116b from the upstream side toward the downstream side.

[0031] In this way, since the ventilation area is ensured and the bulging of the gap retaining member 120b toward the upstream ventilation surfaces 115a, 115b is suppressed, the pleat spacing at the beginning of use can be maintained. Furthermore, since the amount of material increases, the shape stability of the filter assembly 103 is improved even during continuous ventilation, thereby suppressing the increase in pressure loss.

[0032] Furthermore, in the filter assembly 103 of FIG6, although an example is shown in which a plurality of spacer members 120b are continuously formed in the general X direction on the downstream ventilation surfaces 116a, 116b, as shown in the filter assembly 203 of FIG7 as the fourth modified example, a single spacer member 120b may also be formed in a strip shape in the entire general X direction of the downstream ventilation surfaces 116a, 116b. [Simplified Explanation of the Diagram]

[0009] [Fig. 1] shows a perspective view of an air filter according to one embodiment of the air filter of the present invention. [Fig. 2] shows a portion of the folded filter assembly viewed in the direction of elongation of the pleats. [Fig. 3] is a partial enlarged view of Fig. 2. [Fig. 4] is a partial enlarged view of the filter assembly as a first modified example. [Fig. 5] is a partial enlarged view of the filter assembly as a second modified example. [Fig. 6] is a filter assembly as a third modified example, showing a portion of the folded filter assembly viewed in the direction of elongation of the pleats. [Fig. 7] is a filter assembly as a fourth modified example, showing a portion of the folded filter assembly viewed in the direction of elongation of the pleats.

Claims

1. A filter assembly, characterized by comprising: a filter material for capturing microparticles in a gas, having: alternating pleats on the upstream and downstream sides of an airflow formed by pleating; at least one pair of upstream ventilation surfaces through which the airflow flows in, with the aforementioned pleats on the downstream side facing each other; and at least one pair of downstream ventilation surfaces through which the airflow flows out, with the aforementioned pleats on the upstream side facing each other; and a plurality of spacer members formed on each of the aforementioned upstream ventilation surfaces and each of the aforementioned downstream ventilation surfaces to maintain the spacing between each of the aforementioned pairs of upstream ventilation surfaces and each of the aforementioned pairs of downstream ventilation surfaces, wherein the plurality of spacer members formed on the aforementioned upstream ventilation surfaces are intermittently formed in a direction orthogonal to the aforementioned pleats; and at least one of the aforementioned spacer members formed on one of the aforementioned pairs of upstream ventilation surfaces contacts at least two locations with at least one of the aforementioned spacer members formed on the other of the aforementioned pairs of upstream ventilation surfaces.

2. As in the filter component of request item 1, wherein, The aforementioned plurality of spacer retaining members formed on the aforementioned downstream ventilation surface are intermittently formed in a direction orthogonal to the aforementioned crease, and at least one of the aforementioned spacer retaining members formed on one of the aforementioned pair of downstream ventilation surfaces makes contact with at least one of the aforementioned spacer retaining members formed on the other of the aforementioned pair of downstream ventilation surfaces at more than two locations.

3. As in request item 1, the filter component, wherein, The aforementioned plurality of spacer members formed on each of the aforementioned downstream ventilation surfaces are formed continuously in a direction orthogonal to the aforementioned creases.

4. The filter components for requests 1 through 3, wherein, At least one of the aforementioned spacer retaining members formed on the upstream ventilation surface of the aforementioned pair on one of the aforementioned parties makes contact with a plurality of adjacent spacer retaining members formed on the upstream ventilation surface of the aforementioned pair on the other party at more than two locations.

5. The filter components for requests 1 to 3, wherein, The plurality of spacer members formed on each of the aforementioned upstream ventilation surfaces or each of the aforementioned downstream ventilation surfaces have different heights depending on the spacer set between the aforementioned pair of upstream ventilation surfaces or the aforementioned pair of downstream ventilation surfaces.

6. The filter components for requests 1 to 3, wherein, Each of the aforementioned spacer retaining members formed on the upstream ventilation surface of the aforementioned pair of the aforementioned party or the downstream ventilation surface of the aforementioned pair of the aforementioned party has an opposing surface relative to each of the aforementioned spacer retaining members formed on the upstream ventilation surface of the aforementioned pair of the aforementioned party or the downstream ventilation surface of the aforementioned pair of the aforementioned party. The sum of the lengths of the opposing surfaces along the direction orthogonal to the aforementioned creases that contact each of the aforementioned spacer retaining members formed on the upstream ventilation surface of the aforementioned pair of the aforementioned party or the downstream ventilation surface of the aforementioned pair of the aforementioned party is more than 1% and less than 10% of the length along the direction orthogonal to the aforementioned creases of the opposing surfaces.

7. An air filter, characterized in that it comprises: the filter assembly described in any one of claims 1 to 6, and a frame surrounding the filter assembly, wherein the frame arranges the aforementioned creases of the filter material of the filter assembly on the upstream and downstream sides of the airflow passing through the filter material.

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