Filter pack and air filter including the same

Abstract

[Problem] Provided are a filter pack capable of suitably maintaining intervals between pleats while suppressing an increase in pressure loss, and an air filter provided with the same. [Solution] The present invention comprises: a filtering medium having a plurality of pairs of ventilation surfaces 14a, 14b collecting fine particles in a gas, and continuing and facing each other through pleat lines provided in alternatingly repeated fashion by pleating; and an interval holding member 20 holding an interval between each of the plurality of pairs of ventilation surfaces 14a, 14b, formed on at least one of the pair of ventilation surfaces 14a, 14b in such a manner as to extend in a direction orthogonal to the pleat line, and having a base material layer 21 and at least one interval forming layer 22 formed on the base material layer 21.

Description

Technical Field

[0001] The present invention relates to a filter pack including a pleated filter medium and an air filter including the same.

Background Art

[0002] Conventionally, a filter pack in which a spacer member is formed on a pleated filter medium so that the pleat intervals are kept uniform is known. For example, Patent Document 1 discloses a filter pack in which a spacer member is formed by transferring a hot melt adhesive applied to a jig onto a filter medium.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the spacer member is formed on the filter medium by transfer, there is an advantage that it is easy to control the required height and outer shape as the spacer member.

[0005] Here, a hot melt adhesive such as a thermoplastic resin is required to be softened in order to enhance the adhesiveness with the filter medium. However, when it is formed on the filter medium by transfer, if the hot melt resin is softened to obtain adhesiveness, the lower part of the spacer member may spread horizontally after transfer, and there is a risk that a desired shape cannot be obtained.

[0006] The present invention has been made in consideration of such circumstances, and an object thereof is to provide a filter pack that can suitably maintain the pleat intervals while suppressing an increase in pressure loss, and an air filter including the same.

Means for Solving the Problems

[0007] In order to solve the above-described problems, the filter pack according to the present invention includes a filter medium that collects fine particles in a gas and has a plurality of pairs of continuous and opposing ventilation surfaces via folds that are alternately repeated by pleating, and a spacing holding member that holds the spacing between each of the pairs of ventilation surfaces, the spacing holding member being formed to extend in a direction orthogonal to the folds on at least one of the pairs of ventilation surfaces and including a base material layer and at least one spacing formation layer formed on the base material layer.

[0008] Further, the air filter according to the present invention includes the above-described filter pack and a frame that surrounds the filter pack such that the folds of the filter medium of the filter pack are disposed on the upstream side and the downstream side in the air flow direction passing through the filter medium.

Effect of the Invention

[0009] In the filter pack according to the present invention and the air filter including the same, it is possible to suitably maintain the pleat interval while suppressing an increase in pressure loss.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0011] Embodiments of a filter pack and an air filter according to the present invention will be described with reference to the accompanying drawings.

[0012] FIG. 1 is an external perspective view showing an air filter 1 according to an example of the present embodiment. FIG. 2 is a view showing a part of the folded filter pack 3 as viewed in the direction in which the creases of the pleats extend. FIG. 3 is a view showing a ventilation surface 14b on which the spacing holding member 20 is formed. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3.

[0013] The air filter 1 includes a filter pack 3 and a frame body 5. The frame body 5 surrounds the filter pack 3 such that the creases of the filter medium 11 of the filter pack 3 are arranged on the upstream side and the downstream side in the air flow direction (X direction) passing through the filter medium 11. The filter pack 3 has a filter medium 11 and a plurality of spacing holding members 20.

[0014] The filter medium 11 is a member that collects fine particles in the gas. The filter medium 11 is used, for example, for removing dust having a particle size of 2.5 μm or less and a concentration of 0.3 mg / m 3 or less, and has a collection efficiency of 80% or more by the counting method, a pressure loss of 79 to 493 Pa, and a dust holding capacity (dust retention amount) of 200 to 800 g / m 2 is used. In the counting method, measurement is performed by passing air containing particles of any one of atmospheric dust, polyalphaolefin (PAO), and silica having a particle size of 0.3 μm. The dust holding capacity is the amount of dust collected until the filter reaches a predetermined final pressure loss. Further, the filter medium 11 may be, for example, a filter medium for a HEPA filter, a filter medium for a ULPA filter, or a filter medium for a gas removal filter.

[0015] The filter medium 11 is, for example, a fibrous body made of glass fiber, organic fiber, or a mixed fiber of these fibers, and is, for example, a non-woven fabric or a felt. The filter medium 11 made of glass fiber is produced, for example, by papermaking by a wet method or a dry method. The filter medium 11 made of organic fiber is produced, for example, by a spunbond method, a meltblown method, a thermal bonding method, a chemical bonding method, or the like. Further, the filter medium 11 may be, for example, a laminate of a plurality of non-woven fabrics having different collection efficiencies.

[0016] The filter medium 11 is pleated into a substantially V-shaped form such that mountain folds and valley folds are alternately repeated. The pleating is performed using a reciprocating or rotary folding machine or the like. By being pleated, the filter medium 11 has mountain fold portions 12 composed of folds and valley fold portions 13 composed of folds that are parallel to each other. Further, the filter medium 11 has a plurality of pairs of ventilation surfaces 14a and 14b that are continuous and opposed via the mountain fold portions 12 or the valley fold portions 13. In the present embodiment, for convenience, the fold located on the upstream side (-X direction) of the air flow is referred to as the mountain fold portion 12, and the fold located on the downstream direction (+X direction) of the air flow is referred to as the valley fold portion 13.

[0017] The interval holding member 20 is a member that holds the interval (pleat interval) between the pair of ventilation surfaces 14a and 14b of the filter medium 11. The interval holding member 20 is intermittently formed in a direction (substantially the X direction) orthogonal to the folds on one of the pair of ventilation surfaces 14a and 14b, i.e., the ventilation surface 14b. In FIGS. 2 and 3, it is formed in three divided locations.

[0018] The spacing maintaining member 20 (20a, 20b, 20c) has a base material layer 21 and a spacing forming layer 22. The base material layer 21 is a layer formed directly on the ventilation surface 14b and functions as the base (foundation) of the spacing maintaining member 20 extending in the height direction. The spacing forming layer 22 is a layer formed by being laminated on the base material layer 21, and its thickness (substantially the length in the Y direction) is set according to the required height of the spacing maintaining member 20. Further, as shown in FIG. 4, the spacing forming layer 22 is formed such that the width (length in the Z direction) in the direction parallel to the crease direction of the contact surface 22a with the base material layer 21 is equal to or less than the width in the direction parallel to the crease direction of the contact surface 21a with the filter medium 11 of the base material layer 21.

[0019] The spacing maintaining member 20 has a portion where only the base material layer 21 is formed and a portion where the base material layer 21 and the spacing forming layer 22 are formed, according to the pleat interval. Further, the spacing maintaining member 20 has a plurality of layers of the spacing forming layer 22 according to the pleat interval. In FIG. 2, the spacing maintaining member 20a formed at the position where the pleat interval is the smallest (the tapered portion of the V shape of the filter medium 11) has only the base material layer 21. The spacing maintaining member 20b adjacent to this spacing maintaining member 20a has one layer of the spacing forming layer 22 on the base material layer 21. Further, the spacing maintaining member 20c adjacent to this spacing maintaining member 20b and formed at the position where the pleat interval is the largest (the opening portion of the V shape) has two layers of the spacing forming layer 22 on the base material layer 21.

[0020] The spacing maintaining member 20 is made of, for example, a thermoplastic resin called a hot melt adhesive. Examples of such thermoplastic resins include polyamide-based, urethane-based, or olefin-based thermoplastic resins. The spacing maintaining member 20 is formed, for example, by directly applying a hot melt adhesive to the filter medium 11 in a direction orthogonal to the crease of the filter medium 11 using a gun filled with a softened hot melt adhesive.

[0021] Here, from the perspective of the adhesiveness to the ventilation surface 14b (filter medium 11), the base material layer 21 is required to have fluidity (softness) during adhesion. However, due to its fluidity, after being applied to the ventilation surface 14b, it sags and spreads over the filter medium 11, resulting in an increase in the width (Z-direction length) of the contact surface 21a. Also, if an attempt is made to obtain the required height of the spacer member 20 with the base material layer 21, the application amount of the hot melt adhesive will increase. As described above, at the same time, the width of the contact surface 21a also increases. This may reduce the effective area of the filter medium 11, leading to a decrease in the collection efficiency and an increase in the pressure loss.

[0022] Therefore, in the present embodiment, the adhesiveness of the spacer member 20 to the ventilation surface 14b is borne by the base material layer 21, and the function of forming the required height as the spacer function of the spacer member 20 is borne by the spacer formation layer 22. As a result, for the base material layer 21, it can be formed by applying a hot melt adhesive in an amount that does not reduce the effective area of the filter medium 11 and can obtain the required adhesiveness with the filter medium 11. Also, for the spacer formation layer 22, since it is made of the same material as the base material layer 21, it has better adhesiveness than the filter medium 11 and does not require softness as compared to the base material layer 21. For this reason, the spacer formation layer 22 has good formability without sagging toward the filter medium 11 side after application, and it is easy to apply a desired amount. As a result, the spacer formation layer 22 can be controlled to a desired height.

[0023] Such a filter pack 3 and air filter 1 can suitably maintain the pleat interval while suppressing an increase in the pressure loss. That is, since the spacer member 20 has a multi-stage configuration of the base material layer 21 and the spacer formation layer 22, the spacer member 20 does not reduce the effective area of the filter medium 11 as compared with the case of a single-stage configuration. Also, since the spacer member 20 is intermittently formed in the direction orthogonal to the fold, the area covering the filter medium 11 can be reduced. Thereby, the filter pack 3 and the air filter 1 can reduce the increase in the pressure loss associated with the reduction of the ventilation surface 14b due to the provision of the spacer member 20.

[0024] Further, the spacing formation layer 22 is formed such that, in the hot-melt adhesive application step, the width in the direction parallel to the fold direction of the contact surface 22a with the base material layer 21 is equal to or less than the width in the direction parallel to the fold direction of the contact surface 21a between the base material layer 21 and the filter medium 11. Thereby, it is possible to prevent the spacing formation layer 22 from hanging down from the base material layer 21 and covering the ventilation surface 14b of the filter medium 11.

[0025] Although several embodiments have been described in the present disclosure, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

[0026] For example, as shown in FIG. 5 showing a filter pack 3 as a modification corresponding to FIG. 2, the spacing holding member 20 may be arranged so as to be in contact with at least a part of the surfaces of both of the opposing pair of ventilation surfaces 14a and 14b. By arranging the spacing holding member 20 on both of the ventilation surfaces 14a and 14b, the height of each spacing holding member 20 can be made lower than in the case where the spacing holding member 20 is provided only on one ventilation surface. In this case, the presence or absence and the number of layers of the spacing formation layer 22 may be appropriately determined according to the required spacing between the ventilation surfaces 14a and 14b.

[0027] Also, as shown in FIG. 6, which shows the spacing member 20 as a modification corresponding to FIG. 4, the base material layer 21 may be formed in two rows (multiple rows) in a direction orthogonal to the fold line, and the spacing formation layer 22 may be formed so as to straddle them. At this time, the "width in the direction parallel to the fold line of the contact surface between the base material layer and the filter medium" is the distance d in FIG. 6. That is, when the base material layer 21 is formed in multiple rows, it means the total length of the base material layer 21 in the width direction. Also, the "width in the direction parallel to the fold line of the contact surface with the base material layer" of the spacing formation layer 22 is the distance D. That is, it means the total length of the portion in contact with the base material layer 21 in the width direction. The spacing formation layer 22 is applied so as to straddle the two rows of the base material layer 21 and fit between the two rows of the base material layer 21 during formation. For this reason, the positioning of the spacing formation layer 22 is easy, and it is possible to avoid the situation where the hot melt adhesive for forming the spacing formation layer 22 leaks out from the distance d in the width direction of the base material layer 21 and reduces the effective area of the filter medium 11.

[0028] Furthermore, it is not necessary to form the base material layer 21 with a uniform thickness, and the thermoplastic resin may be formed with the necessary thickness and amount in the portion necessary for the adhesiveness with the spacing formation layer 22. For example, as shown in FIG. 7, which shows the spacing member 20 as another modification corresponding to FIG. 4, the resin amount at the center in the width direction of the base material layer 21 may be reduced, and a recess 21b for accommodating the spacing formation layer 22 may be formed. Thereby, similar to the spacing member 20 in FIG. 6, the positioning of the spacing formation layer 22 can be facilitated, and at the same time, the adhesion area of the base material layer 21 and the spacing formation layer 22 can be increased, and the adhesiveness can be improved.

[0029] When the spacing member 20 is formed on one ventilation surface 14b as in the filter pack 3 shown in FIG. 2, a thermoplastic resin similar to the spacing member 20 may be thinly applied to the ventilation surface 14a to maintain the shape of the ventilation surface 14a.

[0030] The spacing maintaining member 20 may be formed of a material such as urethane, rubber, resin, ceramic, etc., which is formed by applying it onto the filter medium 11 in a softened state instead of a hot melt adhesive. The spacing maintaining member 20 may be continuously formed without being intermittently formed in a direction orthogonal to the fold line. The spacing maintaining member may have a spacing forming layer laminated on the base material layer throughout. That is, there may or may not be a portion consisting only of the base material layer 21 like the spacing maintaining member 20. In the length direction (substantially X direction) of the spacing maintaining member 20, the length of the contact surface 22a between the spacing forming layer 22 and the base material layer 21 may be formed to be equal to or less than the length of the contact surface 21a between the base material layer 21 and the filter medium 11.

Explanation of Signs

[0031] 1 Air filter 3 Filter pack 5 Frame 11 Filter medium 14a Ventilation surface 14b Ventilation surface 20, 20a, 20b, 20c Spacing maintaining member 21 Base material layer 21a, 22a Contact surface 22 Spacing forming layer

Claims

1. a filter medium that collects fine particles in a gas and has a plurality of pairs of continuous opposing ventilation surfaces via folds that are alternately repeated by pleating; a spacing holding member that holds the spacing between each pair of the ventilation surfaces, the spacing holding member being formed to extend in a direction orthogonal to the folds on at least one of the pair of ventilation surfaces, and having a base material layer and at least one spacing forming layer formed on the base material layer; the base material layer is a filter pack formed by being divided into a plurality of rows in a direction orthogonal to the folds.

2. the filter pack according to claim 1, wherein the spacing holding member is formed to extend intermittently in a direction orthogonal to the folds.

3. the filter pack according to claim 1 or 2, wherein the spacing forming layer is formed such that the width in a direction parallel to the direction of the folds of the contact surface with the base material layer is equal to or less than the width in a direction parallel to the direction of the folds of the contact surface between the base material layer and the filter medium.

4. a filter pack according to any one of claims 1 to 3; an air filter, comprising a frame body surrounding the filter pack such that the folds of the filter medium of the filter pack are disposed on the upstream side and the downstream side in the airflow direction passing through the filter medium.

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