Filter pack and air filter provided therewith

Abstract

Provided is a filter pack 3, comprising: a filtering material 11 that has pleated folds 12, 13 alternately appearing on an air upstream side and downstream side, a plurality of pairs of air inflow surfaces 14 that are continuous via the folds 13 and form V-shapes, and a plurality of pairs of air outflow surfaces 15 that are continuous via the folds 12 and form V-shapes; and a plurality of rows of spacing retention members 20 that are arranged in a direction running along the folds 12, 13 on the inflow surfaces 14 and the outflow surfaces 15 and retain a spacing between the inflow surfaces 14 and the outflow surfaces 15. Furthermore, the filter pack comprises: bulge prevention members 40 that are arranged between the spacing retention members 20 on the pairs of inflow surfaces 14, maintain spacing between the pairs of inflow surfaces 14, and also have contact surfaces 41 fixed to one another; or bulge prevention members 40 that are arranged between the spacing retention members 20 on the pairs of outflow surfaces 15 and maintain a spacing between the pairs of outflow surfaces 15 retained by the spacing retention members 20 during ventilation. Also provided is an air filter comprising the filter pack.

Description

Filter pack and air filter including same

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

[0002] Conventionally, there has been known a filter pack in which a plurality of spacing members are formed along the fold direction of a pleated filter medium to maintain uniform pleat spacing. For example, Patent Document 1 discloses a filter pack in which opposing spacing members contact each other to maintain spacing.

[0003] Japanese Patent Application Laid-Open No. 2020-062610

[0004] The spacing members maintain the pleat spacing properly during transport or when the filter pack is not ventilated. However, when the filter pack is in use and ventilation is in operation, the filter media between adjacent spacing members in the fold direction swell due to the ventilation. The swelled filter media come into contact with each other on the outflow surface, which impedes air flow and increases pressure loss.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a filter pack that can suppress an increase in pressure loss, and an air filter including the same.

[0006] In order to solve the above-mentioned problems, the filter pack of the present invention comprises a filter medium having pleated folds that alternate between the upstream and downstream sides of the air, multiple pairs of inlet surfaces through which the air flows and that form a continuous V-shape via the folds, and multiple pairs of outlet surfaces through which the air flows and that form a continuous V-shape via the folds; spacing members arranged in multiple rows on the pair of inlet surfaces and the pair of outlet surfaces in a direction along the folds to maintain the spacing between the pair of inlet surfaces and the pair of outlet surfaces; and further comprising bulge prevention members arranged on the pair of inlet surfaces between the spacing members on the pair of inlet surfaces adjacent to each other in the direction along the folds, the bulge prevention members having contact surfaces that are fixed to each other and maintaining the spacing between the pair of inlet surfaces maintained by the spacing members during ventilation, or the filter pack comprises bulge prevention members arranged on the pair of outlet surfaces between the spacing members on the pair of outlet surfaces adjacent to each other in the direction along the folds to maintain the spacing between the pair of outlet surfaces maintained by the spacing members during ventilation.

[0007] In the filter pack according to the present invention and the air filter including the same, an increase in pressure loss can be suppressed.

[0008] 1 is an external perspective view showing one embodiment of an air filter of the present invention; a cross-sectional view along the airflow direction including a spacing member of this embodiment; a cross-sectional view along the airflow direction including a bulge prevention member of this embodiment; an explanatory diagram of a problem with a filter pack as a comparative example; an explanatory view showing the filter pack of this embodiment from the inflow surface side; an explanatory view showing the filter pack of this embodiment from the outflow surface side; an external perspective view showing another embodiment of an air filter of the present invention; a cross-sectional view along the airflow direction including a spacing member of another embodiment; a cross-sectional view along the airflow direction including a bulge prevention member of another embodiment; an explanatory view showing the filter pack of another embodiment from the outflow surface side; an explanatory view showing the filter pack of another embodiment from the inflow surface side; a cross-sectional view along the airflow direction including a bulge prevention member of yet another embodiment; a graph showing the progress of pressure loss in a long-term ventilation test for a filter pack of this embodiment having a bulge prevention member and a filter pack as a comparative example not having a bulge prevention member.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter pack and an air filter including the same according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1 is a perspective view showing an external appearance of an air filter 1 which is an embodiment of the air filter of the present invention.

[0011] FIG. 2 is a cross-sectional view along the airflow direction including the spacing member 20.

[0012] FIG. 3 is a cross-sectional view along the airflow direction including the bulge prevention member 40.

[0013] The air filter 1 includes a filter pack 3 and a frame 5 .

[0014] The frame 5 surrounds and houses the filter pack 3, exposing the inlet face 14 and the outlet face 15 of the filter pack 3. That is, the frame 5 surrounds the filter pack 3 so that the folds 12, 13 of the filter medium 11 are located upstream and downstream in the airflow direction (X direction), which is the direction in which air flows through the filter medium 11. In this embodiment, for convenience, the fold located upstream of the airflow (-X direction) is referred to as fold 12, and the fold located downstream of the airflow (+X direction) is referred to as fold 13.

[0015] The filter pack 3 includes a filter medium 11 , a spacing member 20 , and a bulge prevention member 40 .

[0016] The filter material 11 is a member that captures fine particles in the gas. For example, the filter material 11 is a material having a particle size of 2.5 μm or less and a concentration of 0.3 mg / m 3 The filter medium 11 is used to remove the following dust particles: For example, the filter medium 11 has a collection efficiency of 80% or more by the counting method, a pressure loss of 79 to 493 Pa, and a dust retention capacity (dust amount) of 200 to 800 g / m 2 In the counting method, the collection efficiency is measured by passing air containing atmospheric dust particles, polyalphaolefin (PAO) or silica particles with a particle size of 0.3 μm through the filter. The dust holding capacity is the amount of dust collected by the filter until it reaches a predetermined final pressure drop. 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.

[0017] The filter medium 11 is a fibrous body made of, for example, glass fiber, organic fiber, or a mixture of these fibers, such as a nonwoven fabric or felt. The filter medium 11 made of glass fiber is produced, for example, by papermaking using a wet method or a dry method. The filter medium 11 made of organic fiber is produced, for example, by a spunbond method, meltblowing method, thermal bond method, chemical bond method, or the like. The filter medium 11 may also be, for example, a laminate of multiple nonwoven fabrics with different collection efficiencies.

[0018] The filter medium 11 is pleated into a generally V-shape by alternately folds in the form of mountain and valley folds (creases 12, 13). The pleating is performed using a reciprocating or rotary folding machine. The pleating results in the filter medium 11 having the folds 12, 13, multiple pairs of inlet faces 14, and multiple pairs of outlet faces 15.

[0019] The folds 12, 13 appear alternately on the upstream and downstream sides of the air. The pairs of inlet surfaces 14 are surfaces through which air flows in and form a continuous V-shape via the folds 12. The pairs of outlet surfaces 15 are surfaces through which air flows out and form a continuous V-shape via the folds 13.

[0020] The spacing members 20 maintain the spacing (pleat spacing) between the pair of inflow surfaces 14 and the pair of outflow surfaces 15. Specifically, the spacing members 20 are arranged on the pair of inflow surfaces 14 and outflow surfaces 15 so as to face each other in the Y direction, and maintain the pleat spacing by contacting each other. The opposing spacing members 20 do not need to be in contact over the entire surface, but may be in contact partially (approximately both ends in the X direction in FIG. 2 ).

[0021] The spacing members 20 are arranged intermittently substantially along the X direction in order to prevent a reduction in the ventilation area. In other words, the spacing members 20 made up of a plurality of member pieces are arranged substantially along the X direction.

[0022] Furthermore, the spacing members 20 have appropriate heights (lengths in the Y direction) that vary depending on the pleat spacing. For example, in Fig. 2, the pleat spacing between the pair of inflow surfaces 14 increases from fold 12 toward fold 13, so the height of the spacing members 20 on the fold 12 side is greater and the height of the spacing members 20 on the fold 13 side is smaller.

[0023] 1, the spacing members 20 are arranged in multiple rows in the Z direction on the pair of inflow surfaces 14 and the pair of outflow surfaces 15. The spacing members 20 are preferably arranged evenly in the Z direction at intervals of, for example, 30 mm.

[0024] The spacing 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, and olefin-based thermoplastic resins. The spacing member 20 is formed, for example, by using a gun filled with softened hot melt adhesive to directly apply the hot melt adhesive to the filter medium 11 in a direction perpendicular to the folds 12 and 13. Alternatively, the spacing member 20 may be formed by adhering solidified hot melt adhesive to the filter medium 11, instead of directly applying the adhesive. The spacing member 20 may also be made of other materials, such as ceramic.

[0025] The bulge prevention members 40 maintain the spacing between the pair of inlet surfaces 14 held by the spacing members 20 during ventilation, and prevent the inlet surfaces 14 from bulging downstream. Specifically, the bulge prevention members 40 are arranged only on the pair of inlet surfaces 14 so as to face each other in the Y direction (see FIGS. 5 and 6 ). The bulge prevention members 40 are arranged intermittently substantially along the X direction (a direction substantially perpendicular to the folds 12). In other words, the bulge prevention members 40, each made up of a plurality of pieces, are arranged substantially along the X direction. Furthermore, like the spacing members 20, the bulge prevention members 40 have an appropriate height that varies depending on the pleat spacing.

[0026] The bulge prevention members 40, which are arranged on each of a pair of inflow surfaces 14 and face each other, have contact surfaces 41 that come into contact with each other. The contact surfaces 41 are fixed, for example, with an adhesive or the like, so that they do not separate. Specifically, the contact surface 41 of one member piece arranged on one pair of inflow surfaces 14 is fixed at both ends 42 in the X direction to the contact surfaces 41 of two member pieces arranged on the other pair of inflow surfaces 14. Note that, although the opposing spacing members 20 come into contact with each other, they are not fixed together.

[0027] The bulge prevention members 40 are disposed between the spacing members 20 on a pair of inflow surfaces 14 adjacent in the Z direction on the pair of inflow surfaces 14. As shown in Fig. 1, the bulge prevention members 40 are preferably disposed approximately midway between the spacing members 20 on the pair of inflow surfaces 14 adjacent in the Z direction. In other words, when adjacent spacing members 20 in the positive and negative Z directions are disposed at intervals of 30 mm, the bulge prevention members 40 are preferably disposed 15 mm from each spacing member 20.

[0028] The bulge prevention member 40 is made of substantially the same material as the spacing member 20, for example, a hot melt adhesive.

[0029] Next, the operation of the filter pack 3 and the air filter 1 in this embodiment will be described.

[0030] FIG. 4 is an explanatory diagram showing the problem of the filter pack 3 as a comparative example.

[0031] Fig. 5 is an explanatory view showing the filter pack 3 of this embodiment from the inlet surface 14 side. Fig. 6 is an explanatory view showing the filter pack 3 of this embodiment from the outlet surface 15 side.

[0032] When no ventilation is present, the filter pack 3 (air filter 1) maintains an appropriate pleat spacing by the spacing member 20. When air flows through the filter pack 3 during use, the air passes from the inlet surface 14 to the outlet surface 15, but resistance is generated on the filter medium 11. As a result, as shown in Figure 4, the inlet surface 14 expands toward the outlet surface 15 so that the pleat spacing increases. This narrows the pleat spacing on the outlet surface 15 side, impeding the flow of air and contributing to increased pressure loss.

[0033] Therefore, as shown in Fig. 5, the filter pack 3 of this embodiment has a bulge prevention member 40 disposed on the inlet surface 14 of the filter medium 11. The bulge prevention member 40 is fixed to each other at the contact surface 41. Therefore, the bulge prevention member 40 acts to maintain the pleat spacing, as shown in Fig. 6, against the force of air causing the filter medium 11 to bulge in a direction that increases the pleat spacing.

[0034] Therefore, in the filter pack 3, the spacing member 20 maintains the pleat spacing when there is no ventilation, while the expansion prevention member 40 maintains the pleat spacing when there is ventilation, thereby suppressing an increase in pressure loss during use.

[0035] Next, another embodiment of the filter pack and the air filter including the same according to the present invention will be described with reference to the accompanying drawings. The other embodiment differs from the above embodiment only in the arrangement of the bulge prevention member 40.

[0036] FIG. 7 is a perspective view showing an external appearance of an air filter 1 according to another embodiment of the present invention.

[0037] FIG. 8 is a cross-sectional view along the airflow direction including the spacing member 20.

[0038] FIG. 9 is a cross-sectional view along the airflow direction including the bulge prevention member 40.

[0039] In another embodiment, the bulge prevention members 40 maintain the spacing between the pair of outflow surfaces 15 held by the spacing members 20 during ventilation, preventing the pleat spacing on the outflow surfaces 15 from narrowing. Specifically, the bulge prevention members 40 are arranged only on the pair of outflow surfaces 15 so as to face each other in the Y direction (see FIGS. 10 and 11 ). The bulge prevention members 40 are arranged intermittently substantially along the X direction (a direction substantially perpendicular to the folds 13). In other words, the bulge prevention members 40, each made up of a plurality of pieces, are arranged substantially along the X direction. Similarly to the spacing members 20, the bulge prevention members 40 have an appropriate height that varies depending on the pleat spacing.

[0040] The bulge prevention members 40, which are respectively arranged on a pair of outflow surfaces 15 and face each other, have contact surfaces 41 that come into contact with each other. Specifically, the contact surface 41 of one member piece arranged on one pair of outflow surfaces 15 comes into contact with the contact surfaces 41 of two member pieces arranged on the other pair of outflow surfaces 15 at both ends 42 approximately in the X direction.

[0041] The bulge prevention members 40 are disposed on a pair of outflow surfaces 15 between the spacing members 20 on a pair of outflow surfaces 15 adjacent in the Z direction. The bulge prevention members 40 are preferably disposed approximately midway between the spacing members 20 on a pair of outflow surfaces 15 adjacent in the Z direction (see FIG. 10 ). In other words, when adjacent spacing members 20 in the positive and negative Z directions are disposed at intervals of 30 mm, the bulge prevention members 40 are preferably disposed 15 mm from each spacing member 20.

[0042] The bulge prevention members 40 are made of substantially the same material as the spacing members 20, such as a hot melt adhesive. In addition to being directly applied, the bulge prevention members 40 may be formed by, for example, adhering solidified hot melt adhesive to the filter medium 11. The bulge prevention members 40 may also be a stabilizer inserted between each pair of outflow surfaces 15, which is made of a metal plate such as aluminum, a resin plate, or cardboard, and has a comb-like shape, or a corrugated metal plate such as aluminum, a resin plate, or cardboard.

[0043] Next, the operation of the filter pack 3 and the air filter 1 in another embodiment will be described.

[0044] FIG. 4 is an explanatory diagram showing the problem of the filter pack 3 as a comparative example.

[0045] Fig. 10 is an explanatory view showing the filter pack 3 of this embodiment from the outflow surface 15 side. Fig. 11 is an explanatory view showing the filter pack 3 of this embodiment from the inflow surface 14 side.

[0046] When no ventilation is present, the filter pack 3 (air filter 1) maintains an appropriate pleat spacing by the spacing member 20. When air flows through the filter pack 3 during use, the air passes from the inlet surface 14 to the outlet surface 15, but resistance is generated on the filter medium 11. As a result, as shown in Figure 4, the inlet surface 14 expands toward the outlet surface 15 so that the pleat spacing increases. This narrows the pleat spacing on the outlet surface 15 side, impeding the flow of air and contributing to increased pressure loss.

[0047] 10, a filter pack 3 in another embodiment has bulge prevention members 40 disposed on the outflow surface 15 of the filter medium 11. The bulge prevention members 40 are in contact with each other at the contact surface 41. Therefore, the bulge prevention members 40 act to maintain the pleat spacing, as shown in FIG. 11, against the force of air narrowing the pleat spacing of the filter medium 11.

[0048] Therefore, in the filter pack 3, the spacing member 20 maintains the pleat spacing when there is no ventilation, while the expansion prevention member 40 maintains the pleat spacing when there is ventilation, thereby suppressing an increase in pressure loss during use.

[0049] In the above two embodiments, the bulge prevention members 40 are arranged on either the pair of inflow surfaces 14 or the pair of outflow surfaces 15, but as shown in Figure 12, the bulge prevention members 40 may be arranged on both the pair of inflow surfaces 14 and the pair of outflow surfaces 15. In this case, it is preferable that the bulge prevention members 40 on the inflow surface 14 side and the bulge prevention members 40 on the outflow surface 15 side are arranged so that they do not face each other across the filter medium 11. In the example shown in Figure 12, the bulge prevention members 40 are arranged in two rows and one row alternately in the Y direction and Z direction between the spacing members 20, 20 on the inflow surface 14 side and the spacing members 20 on the outflow surface 15 side. Furthermore, the illustrated bulge prevention members 40 are formed with a smaller cross section than the spacing members 20.

[0050] FIG. 13 is a graph showing the change in pressure loss over time in a long-term ventilation test for the filter pack 3 of the above embodiment having the bulge prevention member 40 and a filter pack as a comparative example not having the bulge prevention member 40.

[0051] 13 , in the comparative filter pack not having the bulge prevention member 40, the pressure loss increases in proportion to the passage of time, as shown in result D2. On the other hand, in the filter pack 3 of this embodiment, as shown in result D1, the presence of the bulge prevention member 40 reduces the ventilation area, resulting in a larger pressure loss than the comparative filter pack in the early stages. However, in the filter pack 3 of this embodiment, no increase in pressure loss is observed even after 500 hours, and there is almost no difference from the initial pressure loss. In other words, it can be seen that in the filter pack 3 of this embodiment, the increase in pressure loss due to the narrowing of the pleat spacing on the outflow surface 15 due to the bulge of the filter medium 11 is suppressed.

[0052] Therefore, the filter pack 3 and the air filter 1 including the same in this embodiment can suppress an increase in pressure loss by maintaining an appropriate pleat spacing.

[0053] Although several embodiments have been described in this disclosure, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied 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 modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0054] For example, the spacing member 20 of the filter pack 3 is an example and is not limited to this. In the present embodiment, an example has been described in which one member piece of the bulge prevention member 40 arranged on one pair of inflow surfaces 14 of the filter pack 3 contacts and is fixed to two member pieces of the bulge prevention member 40 arranged on the other pair of inflow surfaces 14. However, the shape of the bulge prevention member is not limited to this, and any shape may be used as long as the opposing bulge prevention members can be fixed to each other while maintaining the pleat spacing.

[0055] In another embodiment, the bulge prevention members 40 of the filter pack 3 are configured such that one piece of the bulge prevention member 40 arranged on one pair of outflow surfaces 15 contacts and is fixed to two pieces of the bulge prevention member 40 arranged on the other pair of outflow surfaces 15. However, the shape of the bulge prevention member is not limited to this, and any shape may be used as long as the opposing bulge prevention members can contact each other while maintaining the pleat spacing.

[0056] REFERENCE SIGNS LIST 1 Air filter 3 Filter pack 5 Frame 11 Filter material 12, 13 Folds 14 Inlet surface 15 Outlet surface 20 Spacing member 40 Swelling prevention member 41 Contact surface 42 Both ends

Claims

1. A filter pack comprising: a filter medium having pleated folds that alternate on the upstream and downstream sides of the air; a plurality of pairs of inlet surfaces through which the air flows and that form a continuous V-shape via the folds; and a plurality of pairs of outlet surfaces through which the air flows and that form a continuous V-shape via the folds; spacing members arranged in multiple rows on the pair of inlet surfaces and the pair of outlet surfaces in a direction along the folds to maintain the spacing between the pair of inlet surfaces and the pair of outlet surfaces; and further comprising: bulge prevention members arranged on the pair of inlet surfaces between the spacing members on the pair of inlet surfaces adjacent to each other in the direction along the folds, maintaining the spacing between the pair of inlet surfaces maintained by the spacing members during ventilation and having contact surfaces fixed to each other; or bulge prevention members arranged on the pair of outlet surfaces between the spacing members on the pair of outlet surfaces adjacent to each other in the direction along the folds to maintain the spacing between the pair of outlet surfaces maintained by the spacing members during ventilation.

2. The filter pack according to claim 1, wherein the bulge prevention member is positioned approximately midway between the spacing members on the pair of adjacent inlet flow surfaces in a direction along the fold.

3. The filter pack according to claim 1, wherein the bulge prevention member is positioned approximately midway between the spacing members on the pair of adjacent outflow surfaces in a direction along the fold.

4. The filter pack of claim 2, wherein the spacing members on the pair of inlet flow surfaces adjacent in the direction along the fold are spaced approximately 30 mm apart.

5. The filter pack according to claim 3, wherein the spacing members on the pair of outflow surfaces adjacent in the direction along the fold are spaced apart by approximately 30 mm.

6. A filter pack according to claim 1, wherein the bulge prevention member has a plurality of member pieces arranged intermittently along a direction substantially perpendicular to the folds, and the contact surface of one of the member pieces arranged on one of the pair of inlet surfaces is fixed at both ends in the direction substantially perpendicular to the folds to two of the member pieces arranged on the other of the pair of inlet surfaces.

7. A filter pack according to claim 1, wherein the bulge prevention member has a plurality of member pieces arranged intermittently along a direction substantially perpendicular to the fold, and one member piece arranged on one of the pair of outflow surfaces is in contact with two member pieces arranged on the other of the pair of outflow surfaces at both ends in the direction substantially perpendicular to the fold.

8. The filter pack of claim 1, wherein said spacing member and said bulge prevention member are hot melt adhesives.

9. A filter pack as described in claim 1, comprising: a bulge prevention member disposed on the pair of inlet surfaces between the spacing members on the pair of inlet surfaces adjacent to each other in the direction along the fold, the bulge prevention member having contact surfaces fixed to each other, the bulge prevention member maintaining the spacing between the pair of inlet surfaces held by the spacing members during ventilation; and a bulge prevention member disposed on the pair of outlet surfaces between the spacing members on the pair of outlet surfaces adjacent to each other in the direction along the fold, the bulge prevention member maintaining the spacing between the pair of outlet surfaces held by the spacing members during ventilation.

10. The filter pack according to claim 9, wherein the expansion prevention member on the inlet side and the expansion prevention member on the outlet side are arranged so as not to face each other across the filter medium.

11. An air filter comprising: the filter pack according to any one of claims 1 to 10; and a frame that surrounds and exposes the inlet and outlet faces of the filter pack and houses the filter pack.

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