TWI601567B - Filter medium and filter unit - Google Patents

Description

Filter filter and filter unit Technical field

The present invention relates to a filter medium for collecting particles contained in a gas to be filtered, and a filter unit using the filter medium, and more particularly to a filter material which is configured to pleat a filter material which can collect the particles.

Background technique

Heretofore, as the filter medium used in a clean room or the like for manufacturing a semiconductor or liquid crystal factory, a filter medium 100 as shown in Fig. 6 is known. The filter medium 100 is configured such that the filter material 200 that can collect the particles contained in the gas to be filtered is bent at a plurality of points to form a pleat shape.

The filter medium 100 includes a bent portion 100a formed by bending a filter material 200, and a plurality of flat portions 100b formed in a direction other than the bent portion 100a of the filter material 200 to be opposed to each other; and a plurality of intervals The holding portion 300 is a space in which the adjacent flat plate portions 100b and 100b are kept apart from each other.

The space holding portion 300 is formed by a plurality of curling portions 300a formed by applying an adhesive (hot melt adhesive or the like) to the both surfaces of the filter material 200 at intervals. Specifically, the interval maintaining portion 300 is made of a filter material The one side surface side of each of the 200 side faces and the other flat side parts 100b are formed by joining the bead portions 300a and 300a on the one side and the other side. That is, the space holding portion 300 is formed between the flat plate portions 100b on one of the surface side of the filter material 200 and the other side.

As shown in Fig. 7 (a), the filter medium 100 configured as described above is housed in a casing A that is configured to accommodate the filter medium, and constitutes the filter unit 110. The frame A includes a pair of opposing walls A1 and A1 that are disposed to face each other with a gap therebetween, and a connecting wall A2 that connects the outer peripheral portions of the pair of opposing walls A1 and A1. Further, the filter medium 1 can be housed in a space (hereinafter also referred to as an internal space) AR surrounded by the pair of opposing walls A1 and A1 and the connecting wall A2. The pair of opposing walls A1 and A1 include openings A3 and A3 that communicate with the internal space AR. Thereby, the casing A is configured such that the filtered gas can pass through the internal space AR from the one opening A3 side toward the other opening A3 side.

The filter medium 100 accommodated in the frame A is disposed on the side of the pair of facing walls A1 in the internal space AR, and the outer peripheral portion is fixed to the frame A. Thereby, a space is formed between the filter medium 100 and the other opposing wall A1.

The filter unit 110 configured as described above is disposed such that the length L1 direction of the filter medium 100 intersects with the flow direction F of the filtered gas (specifically, it is slightly orthogonal). That is, the filter unit 110 is disposed such that the filtered gas comes into contact with the filter medium 100 from the height L3 direction of the filter medium 100. Thereby, the filtered gas that has flowed into the inside of the filter unit 110 from the opening A3 of one of the frames A passes through the filter medium 100 in the internal space AR, and is discharged from the other opening A3 of the frame A.

Therefore, if the filtered gas is circulated through the filter unit 110, As shown in Fig. 7(b), the wind pressure of the filtered gas or the pressure loss of the filter medium 100 increases, and the central portion of the filter medium 100 bulges toward the downstream side of the flow direction F of the filtered gas, and has a filter medium. 100 constitutes the state of the bending state.

The bending of such a filter medium 100 is a factor that increases the pressure loss of the filter unit or reduces the filtration efficiency. Moreover, if the bending of the filter medium 100 is too large, the filter unit 110 may be damaged.

As a method of preventing the bending of the filter medium as described above, various methods are currently disclosed. For example, a method has been disclosed which reduces the initial pressure loss of the filter material constituting the filter media or increases the effective area of the filter media, reduces the increase in pressure loss of the filter media over time, and suppresses wind pressure. The resulting filter medium is bent (see Patent Document 1). Further, there has been disclosed a method of attaching a member having a higher rigidity than a filter medium (hereinafter also referred to as a rigid member) to a filter medium, and suppressing bending of the filter medium by the rigid member (see Patent Documents 2 and 3) .

However, in the method of reducing the increase in the pressure loss of the filter medium for a long period of time as described above, there is a possibility that the collection performance of the particles from the filtered gas is lowered. Further, in the method of using a rigid member as described above, it takes a lot of trouble to prepare a filter medium or a filter unit at the cost of preparing a rigid member, and it is a cause of a decrease in production efficiency.

Advanced technical literature Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-292215

[Patent Document 2] Japanese Patent Publication No. 11-42410

[Patent Document 3] International Publication No. 2005/077492

Summary of invention

Therefore, an object of the present invention is to provide a filter medium which can prevent unintentional deformation due to the wind pressure of a filtered gas, and a filter unit using the filter medium.

The filter medium according to the present invention includes a plurality of bent portions formed by folding a material of the filter material contained in the particles of the gas to be filtered into a pleat shape, and a plurality of flat plate portions are other than the bent portion of the filter material. The field is arranged to be opposed to each other; and the plurality of interval holding portions are formed between the flat plate portions on one of the surface side of the filter material and the other side of the filter material to maintain the interval between the adjacent bent portions; The filter medium is configured such that the thickness of the surface-side spacer portion formed on the other side of the filter material is larger than the thickness of the one-side spacer formed on the one surface side of the filter material in the gap holding portion formed on both surfaces of the filter material. thin.

According to the above configuration, the interval between the flat portions in the other side of the filter material is narrower than the interval between the flat portions on the one side of the filter material. Therefore, compared with the both ends of the longitudinal direction of the filter media, the field on the center side is likely to bulge toward the surface side of the filter material, and the filter medium is easily bent. Accordingly, by using the filter medium in a bent state, it is possible to suppress the filter medium from being deformed by the wind pressure of the filtered gas.

Specifically, by bending the filter media as described above, The wind pressure applied to the filter media on the bulging side of the center side of the filter media is increased, and the rigidity of the filter media is increased. Therefore, deformation of the filter media due to wind pressure can be suppressed.

Moreover, it is preferable that the space-retaining portion is formed by a one-side bead portion formed by disposing an adhesive on one surface of the filter material and a side-side bead portion formed by disposing an adhesive on the other side of the filter material. The thickness of the portion where the space holding portion is formed in the side curling portion is formed to be thinner than the thickness of the portion where the space holding portion is formed in the one side curling portion.

According to the above configuration, the thickness of the face-side spacer portion is made thinner than the thickness of the one-side spacer portion. Thereby, it is easy to use the filter media as described above, and it is possible to suppress deformation of the filter media due to wind pressure.

Moreover, it is preferable that the thickness of the portion in which the space holding portion is formed in the one side curling portion is 20% or more and 80% or less of the thickness of the portion where the space holding portion is formed in the side curling portion.

In the filter unit of the present invention, the filter medium is accommodated in a housing that accommodates the filter medium according to any one of the above, and the frame body has an opening that allows the filtered gas to flow into the inside, and the filter medium is bent into The field on the center side is located on the side of the opening and is housed in the frame, compared to the both ends of the long direction.

As described above, according to the present invention, it is possible to prevent unintentional deformation due to the wind pressure of the filtered gas.

1,100‧‧‧Filter media

1a, 100a‧‧‧bend

1b, 100b‧‧‧ flat section

2,200‧‧‧ Filter material

2a‧‧‧Porous layer

2b‧‧‧ substrate layer

3A‧‧‧One side spacer

3B‧‧‧He side interval keeping

3a‧‧‧One side curling

3a’, 3b’, 300a‧‧‧ hem

3b‧‧‧He side curling

10,110‧‧‧Filter unit

300‧‧‧Interval Maintenance Department

A, X‧‧‧ frame

A1‧‧‧Bound booking area

A1 (conventional), X1‧‧‧ opposite wall

A2‧‧‧Scheduled area

A2 (conventional), X2‧‧‧ connecting wall

A3, X3‧‧‧ openings

AR, XR‧‧‧ interior space

F‧‧‧Circulation direction

L1‧‧‧ length

L2‧‧‧Width

L3‧‧‧ Height

XL1‧‧ interval

Fig. 1 is a perspective view showing a filter medium according to the embodiment.

Fig. 2 is a perspective view showing a material of a filter material relating to a filter medium of the same embodiment and a partial enlarged view thereof.

Fig. 3 (a) is a cross-sectional view showing the filter medium of the embodiment cut along the surface intersecting the flat plate portion in the height direction, and (b) the filter medium is cut along the longitudinal direction and the width direction. Sectional view.

Fig. 4 is a cross-sectional view showing a filter unit constructed using the filter medium of the same embodiment.

Fig. 5 is a cross-sectional view showing a gap holding portion of a filter medium according to another embodiment.

Figure 6 is a perspective view showing a conventional filter media.

Fig. 7 (a) is a cross-sectional view of a filter unit configured to accommodate the filter medium of Fig. 6 in a frame, and Fig. 7 (b) is a view showing a state in which the wind pressure of the filtered gas is applied to the filter unit of (a) and the filter medium is bent. Sectional view.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described with reference to Figs. In the following figures, the same or corresponding parts will be denoted by the same reference numerals and the description will not be repeated.

As shown in Fig. 1, the filter medium 1 of the present embodiment includes a plurality of bent portions 1a, and is configured such that the filter material 2 that can collect the particles contained in the gas to be filtered is bent into a pleat shape (hereinafter also referred to as Formed by pleating; The plurality of flat plate portions 1b are formed such that the filter material 2 is disposed in a direction other than the bent portion 1a, and the plurality of the interval holding portions 3A and 3B are formed on one surface side and the other side of the filter material 2; Between the flat plate portions 1b, the adjacent bent portions 1a, 1a are spaced apart from each other.

As shown in FIG. 2, the filter material 2 is formed into a rectangular sheet shape in one direction before being bent into a pleated shape. Further, the filter material 2 may be formed in a long shape and formed into a rectangular shape in one direction, and may be formed into a sheet shape by being unwound from a wound state, or may be formed into a sheet shape and formed into a rectangular piece in one direction. body.

Further, the filter material 2 includes a porous layer 2a that collects particles contained in the gas to be filtered, and a base layer 2b that has air permeability and is laminated on the porous layer 2a. In the present embodiment, the filter material 2 has a plurality of (specifically, two) porous layers 2a, and the base layer 2b is disposed between the porous layers 2a. According to this, the filter material 2 is formed by using the plurality of porous layers 2a, and the pressure loss or the collection efficiency is suppressed from being caused by the formation of the filter material 2 from the single porous layer 2a. Further, since it is possible to suppress the formation of pinholes that penetrate the filter material 2, it is possible to obtain the filter material 2 having a structure that does not leak.

The porous layer 2a is formed using a porous sheet (hereinafter also referred to as a porous sheet) capable of collecting the particles. The porous sheet is not particularly limited and may be appropriately selected depending on the use of the filter medium 1. For example, the porous sheet may, for example, be a PTFE sheet in which polytetrafluoroethylene (PTFE) is formed into a sheet shape; or a melt blown nonwoven fabric, an electrostatic sieve, or a glass fiber. In the present embodiment, a PTFE sheet is used as the porous sheet. Forming a PTFE sheet The method can, for example, adopt the following method.

Specifically, a liquid lubricant is added to the PTFE fine powder to form a paste mixture. The PTFE fine powder is not particularly limited, and examples thereof include Polyflon F-104 (manufactured by Daikin Industries, Ltd.), Fluon CD-123 (made by Asahi ICI Fluoropolymer Co., Ltd.), and Teflon 6J (Mitsui. DuPont). Fluorine chemical company) and so on. The liquid lubricant is not particularly limited as long as it imparts moderate wettability to the surface of the mixture, and is particularly preferably removed by extraction treatment or heat treatment. For example, in addition to the hydrocarbon oil such as liquid paraffin, naphtha, white oil, toluene, xylene, etc., the liquid lubricant may, for example, be an alcohol, a ketone, an ester, or a mixture of two or more thereof. Wait. The amount of the liquid lubricant to be added is not particularly limited, and can be appropriately adjusted depending on the type of the PTFE fine powder and the liquid lubricant, and the molding method for obtaining the PTFE sheet. Specifically, the amount of the liquid lubricant to be added is preferably 5 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the PTFE fine powder.

Further, the mixture of the PTFE fine powder and the liquid lubricant is preliminarily molded to prepare a preliminary molded body. Specifically, a preliminary molded body is produced by extruding the mixture into a rod shape. The preliminary preparation is preferably carried out by a pressure at which the liquid lubricant does not separate from the mixture.

Next, the obtained preliminary formed body is formed into a sheet shape by extrusion molding or calender molding. For example, the method of forming the preliminary molded body into a sheet shape may be a method in which a preliminary molded body is formed into a sheet shape by supplying a preliminary molded body between a pair of roll members and rolling, and the preliminary formed body is formed into a sheet shape. a sheet-like method; or by forming a sheet into a sheet The preliminary molded body is further supplied to a pair of rolls and rolled, and the preliminary molded body is formed into a sheet shape or the like. The thickness of the sheet-like formed body obtained is not particularly limited, and is preferably 0.05 mm or more and 0.5 mm or less, for example.

Next, the obtained sheet-like formed body is made porous by uniaxial stretching or biaxial stretching, and a PTFE sheet is formed. In the present embodiment, the sheet-like formed body extends in the longitudinal direction and also extends in the width direction orthogonal to the longitudinal direction (biaxially extending). Further, it is preferred to remove the liquid lubricant from the molded body before the sheet-like formed body is extended. The liquid lubricant may be removed by a method of heating the molded body (heating method) or a method of extracting a liquid lubricant by immersing the molded body in a solvent (extraction method).

When the sheet-like formed body is extended in the longitudinal direction, the larger the stretching ratio, the higher the expansion ratio of the formed body is, and the porous body is easily made porous. Therefore, for example, the stretching ratio is preferably 10 times or more and 30 times or less. Further, the temperature condition at which the molded body is extended is not particularly limited, and is preferably 150 ° C or more and less than 327 ° C.

By extending the sheet-shaped formed body which has been extended in the longitudinal direction in the width direction, the formed body is effectively fibrillated, and a PTFE sheet having a small error in the pore diameter can be obtained. The condition for extending the sheet-like formed body in the width direction is not particularly limited. For example, the stretching ratio is preferably 20 times or more and 100 times or less. Further, it is preferable that the sheet-like formed body is extended in the width direction to be 450 times or more by the area stretching magnification expressed by the product of the stretching ratio in the case of the previous long-direction extension. The larger the area stretching ratio, the more the fibrillation is further promoted, and a porous PTFE sheet having a large PF value can be obtained. Further, the stretching temperature is not particularly limited, and for example, it is preferably 40 ° C or more and 100 ° C or less.

The PTFE sheet formed as described above has an excellent property of a pressure loss of 50 mmH ₂ O or less and a collection efficiency of 99.9% or more. In particular, when the area extension ratio is 450 times or more, the collection efficiency is not largely lowered, and the pressure loss is reduced to less than 20 mmH ₂ O, and the PF value is 22 or more. Thereby, a porous PTFE sheet having extremely excellent performance can be obtained. Moreover, the error in the pressure loss of each of the obtained PTFE sheets is also reduced. Therefore, it is possible to constitute a porous PTFE sheet having a low work cost and exhibiting extremely excellent dust removal performance.

Further, the PTFE sheet obtained as described above may be further subjected to heat treatment (baking treatment) for the purpose of improving strength or obtaining dimensional stability. In general, the heat treatment of the PTFE sheet is carried out by a fixed size of the temperature above the melting point of the PTFE calcined body. Moreover, the pressure loss can be reduced by the aforementioned heat treatment. Therefore, when the PF value of the PTFE sheet is 22 or more and the pressure loss is 20 mmH ₂ O or more, the pressure loss can be reduced to less than 20 mmH ₂ O by the heat treatment.

The base material layer 2b is formed using a sheet having air permeability (hereinafter also referred to as a breathable sheet). The air permeable sheet is not particularly limited, and examples thereof include non-woven fabrics, woven fabrics, meshes, and polymer fibers. In particular, when the porous layer 2a (porous layer) and the base layer 2b (air permeable sheet) are thermally welded (thermally laminated), it is preferable to use a permeable sheet composed of thermoplastic material.

For example, the material of the air permeable sheet may be, for example, a polyolefin such as polyethylene or polypropylene, a nylon, a polyester, a polyarylamine (specifically, an aromatic polyamine or the like) or a composite thereof. (for example, by the core / sheath structure of the fiber a non-woven fabric composed of a dimension; or a double-layer non-woven fabric of a low-melting point material and a high-melting point material, etc.). In addition, as an example, the material of the air permeable sheet may be, for example, PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene/hexafluoropropylene copolymer), PTFE. A fluorine-based porous film such as a porous membrane.

In particular, it is suitable to use a permeable sheet composed of a conjugate fiber belonging to a core-sheath structure and having a core component which is relatively high in melting point compared to a sheath component; or a low-melting material and high A non-woven fabric composed of two layers of a melting point material. By using such a nonwoven fabric, when the porous layer 2a (porous layer sheet) and the base material layer 2b (air permeable sheet) are thermally laminated, shrinkage due to the base material layer 2b can be suppressed. Moreover, by using the above-mentioned nonwoven fabric, the workability in the pleating process of the filter material 2 is improved, and the bending portion (folding pitch) of the filter material 2 can be increased.

The method of forming the filter material 2 as described above is not particularly limited. For example, a method may be employed in which a hot melt is disposed between the porous sheet forming the porous layer 2a and the air permeable sheet forming the substrate layer 2b. A glue or a pressure sensitive adhesive, and the porous sheet and the air permeable sheet are crimped. Alternatively, a method in which a heat-treated softened air-permeable sheet and a porous sheet are pressure-bonded (thermally laminated) may be employed.

The filter material 2 configured as described above forms the bead portions 3a and 3b constituting the space holding portions 3A and 3B. The beading portions 3a and 3b are formed after the corrugated material 2 is pleated. Specifically, the filter material 2 is bent at a plurality of points in a width direction orthogonal to one direction (long direction) to be pleated, and then stretched to a flat state before the pleat processing, and by the filter material 2 The adhesive is applied to both sides to form the curled portions 3a, 3b. The shape of the curling portions 3a and 3b is not particularly limited, and in the present embodiment, along one direction of the filter material 2 (long direction) Formed as a line.

a beading portion (hereinafter also referred to as a one-side beading portion) 3a formed on one surface side of the filter material 2 and a bead portion formed on the other side of the filter material 2 (hereinafter also referred to as a side curling portion) 3b is formed at a plurality of the filter material 2. Specifically, the one side curling portion 3a and the other side curling portion 3b are formed in plural along the direction (longitudinal direction) of the filter material 2. Further, the one side curling portion 3a and the other side curling portion 3b are arranged in one direction (long direction) in the direction of the filter material 2 (further, they do not overlap the filter material 2). Further, the one side curling portion 3a and the other side curling portion 3b are arranged in plural at intervals along the width direction of the filter material 2 (three in the present embodiment).

The one side curling portion 3a and the other side curling portion 3b are formed so as to intersect (slightly orthogonal) the region (hereinafter also referred to as a predetermined bending region) A1 which constitutes the bent portion 1a when the filter material 2 is pleated. Specifically, in the adjacent predetermined bending areas A1, A1, one bending predetermined area A1 and one side side curling portion 3a are intersected, while the other bending predetermined area A1 and the other side side curling portion 3b are formed. cross. Moreover, the one side side curling part 3a and the other side side curling part 3b are formed in the surface of the protrusion part side of the bending part 1a in each bending predetermined area A1.

In addition, the one side side beading part 3a and the other side side beading part 3b are formed on both surfaces of the field of the flat plate part 1b (hereinafter also referred to as a predetermined area of the flat plate portion) A2 when the filter material 2 is pleated. Specifically, the one side curling portion 3a and the other side curling portion 3b are formed from the intersection of the predetermined predetermined area A1 and the substantially central portion of the predetermined area A2 of the flat portion.

Further, the one-side curling portion 3a and the other-side curling portion 3b which are formed as described above are configured as the side-side curling portion 3b (in detail, the gap is formed). The thickness of the portion of the holding portion 3B is thinner than the thickness of the one side side bead portion 3a (in detail, the portion where the space holding portion 3A is formed). Specifically, the coating amount of the adhesive applied to the other side of the filter material 2 is smaller than the amount of the adhesive applied to the one surface side, and the thickness of the side curling portion 3b is smaller than that of the side surface. The thickness of the side portion 3a is thin. The ratio of the thickness of the side surface side bead portion 3b with respect to the thickness of the one side side bead portion 3a is preferably 20% or more and 80% or less, and more preferably 40% or more and 60% or less. The thickness of each of the curling portions 3a and 3b is the thickness of the respective curling portions 3a and 3b disposed on both surfaces of the filter material 2 corresponding to the thickness direction of the filter material 2 .

The adhesive constituting the one side curling portion 3a and the other side curling portion 3b is not particularly limited, and for example, a hot melt adhesive can be used. The temperature at which the hot melt adhesive is applied to the filter material 2 varies depending on the composition of the hot melt adhesive. However, it is preferably 100 ° C or higher and 250 ° C or lower, and more preferably 140 ° C or higher and 230 ° C or lower.

The filter material 2 in which the curling portions 3a and 3b are formed as described above is bent again in each of the predetermined bending regions A1 to form a pleat shape. Thereby, as shown in FIG. 3(a), a plurality of bent portions 1a and a plurality of flat plate portions 1b are formed. Further, each of the curling portions 3a and 3b is formed by joining the portions between the flat plate portions 1b on both surfaces of the filter material 2, and the gap holding portions 3A and 3B are formed. Thereby, the filter medium 1 is formed. When the hot-melt adhesive is used as the adhesive constituting the bead portions 3a and 3b, it is preferable to soften the hot melt adhesive to the extent that it can be joined to each other (opening time), and the filter material 2 is again formed into a pleated shape.

In the following description, the direction corresponding to one direction (longitudinal direction) of the filter material 2 in the filter medium 1 is the length L1 of the filter medium 1. Again, too The direction corresponding to the other direction (width direction) of the filter material 2 in the filter medium 1 is the width L2 of the filter medium 1. Further, the interval between the bent portion 1a on the one side of the filter material 2 and the bent portion 1a on the side of the other side of the filter material 2 is the height L3 of the filter medium 1.

In the filter medium 1 formed as described above, the space holding portions 3A and 3B are formed on one of the surface side and the other side of the filter material 2, respectively. Further, each of the interval holding portions 3A and 3B is formed linearly along the height L3 direction of the filter medium 1. Further, as shown in Fig. 3 (a) and (b), each of the interval holding portions (hereinafter also referred to as a one-side spacer portion) 3A on the one surface side of the filter medium 1 and the respective interval holding portions on the other side (hereinafter also referred to as The face-side spacers 3B are alternately arranged along the length L1 direction of the filter medium 1 (specifically, on a straight line along the length L1 direction).

Moreover, the one side spacer holding portion 3A and the other side spacer holding portion 3B are formed to have different thicknesses. Specifically, the thickness of the one side interval holding portion 3B is formed to be thinner than the thickness of the one side interval holding portion 3A. More specifically, by joining the portions of the other side curling portion 3b which are thinner than the one side curling portion 3a between the flat plate portions 1b, the thickness is thinner than the one side spacer holding portion 3A. Interval holding portion 3B. The ratio of the thickness of the surface-side spacer portion 3B to the thickness of the one-side spacer portion 3A is preferably 20% or more and 80% or less, and more preferably 40% or more and 60% or less. Further, the thickness of each of the interval holding portions 3A and 3B is a thickness corresponding to a direction in which the adjacent flat plate portions face each other.

With this configuration, the thickness of the face-side spacer holding portion 3B is thinner than the thickness of the one-side spacer portion 3A, as shown in Figs. 3(a) and (b). The interval between the flat portions 1b on the other side of the material 2 is narrower than the interval between the flat portions 1b on the one side of the filter material 2.

As shown in FIG. 4, the filter medium 1 configured as described above is stored in the frame X which is configured to accommodate the filter medium 1, and is used as the filter unit 10. The housing X includes a pair of opposing walls X1 and X1 that are disposed to face each other with a gap therebetween, and a connecting wall X2 that connects the outer peripheral portions of the pair of opposing walls X1 and X1. Further, the filter medium 1 can be housed in a space (hereinafter also referred to as an internal space) XR surrounded by the pair of opposing walls X1 and X1 and the connecting wall X2. The pair of opposing walls X1 and X1 have openings X3 and X3 that communicate with the internal space XR. Thereby, the frame body X is configured such that the filtered gas can pass through the internal space XR from the one opening portion X3 side toward the other opening portion X3 side.

The shape of the frame X is not particularly limited as long as it can accommodate the filter medium 1 , and examples thereof include an inner dimension of 1180 mm × 1180 mm, an outer dimension of 1220 mm × 1220 mm, a thickness of 75 mm, or a predetermined shape. The round shape of the inner diameter and the like. Further, the material of the frame X is not particularly limited, and aluminum may be used.

The filter medium 1 is adjusted so that the length L1 is a predetermined length and is accommodated in the frame X. Specifically, the length L1 of the filter medium 1 adjusted (cut) is smaller than the direction of the direction in which the filter medium 1 is accommodated in the frame X (specifically, the direction along the length L1 direction of the filter medium 1) The interval between faces is XL1 long.

Moreover, the filter medium 1 is in a state of being bent in the casing X in a state of being housed in the casing X. Specifically, the filter medium 1 is placed in the frame body X, and both end portions in the length L1 direction abut against the inner surface of the frame body X (more specifically, the inner surface of the connection wall X2), and the phase Compared to the length L1 direction The both ends of the center side are located on the side of one opening X3 than the both ends, and are formed in a state of being curved in the width L2 direction.

In addition, the arc formed by the apex portions of the respective bent portions 1a (in other words, the respective bent portions 1a formed on the sides where the respective flat portions 1b are widened) on the one side of the filter medium 1 is formed. The radius (bending radius) is not particularly limited. For example, it is preferably 250 mm or more and 1500 mm or less, and more preferably 290 mm or more and 1200 mm or less.

A caulking agent is filled between the filter medium 1 and the frame X. For example, the sealant may be, for example, a two-liquid epoxy sealant (specifically, a combination of Henkel's Macroplast 8104MC-18 and Macroplast UK5400 in a ratio of 3:1).

The filter unit 10 is preferably a HEPA (High Efficiency Particulate Air) filter or a ULPA (Ultra Low Penetration Air) filter that is used as a clean room or the like.

The filter unit 10 configured as described above is disposed such that the length L1 direction of the filter medium 1 crosses (specifically, is substantially orthogonal) with respect to the flow direction F of the filtered gas. That is, the filter unit 10 is disposed such that the filtered gas comes into contact with the filter medium 1 from the height L3 direction of the filter medium 1 . Moreover, the filter unit 10 is disposed so that both ends of the filter medium 1 in the longitudinal direction L1 direction are located on the upstream side of the flow direction F of the filtered gas than the both ends. As a result, the filtered gas that has flowed into the inside of the filter unit 10 from the opening portion X3 of one of the frames X passes through the filter medium 1 in the internal space XR and is discharged from the other opening portion X3 of the frame x.

As described above, according to the filter medium and the filter unit of the present invention, it is possible to prevent unintentional deformation due to the wind pressure of the filtered gas.

In other words, the filter medium 1 is configured such that the thickness of the surface side interval holding portion 3B is thinner than the thickness of the one side space holding portion 3A, whereby the flat portions 1b of the other side of the filter material 2 are spaced apart from each other by the filter material. The flat plate portions 1b in one of the face sides are narrowed from each other. Therefore, the field on the center side is more likely to bulge toward the surface side of the filter material 2 than the both end portions of the filter medium 1 in the longitudinal direction, and the filter medium 1 is easily bent. Accordingly, by using the filter medium 1 in a bent state, it is possible to suppress the filter medium 1 from being deformed by the wind pressure of the filtered gas.

Specifically, by bending the filter medium 1 as described above, the rigidity of the filter medium 1 is increased with respect to the wind pressure applied to the filter medium 1 from the bulging side of the center side of the filter medium 1 . Therefore, deformation of the filter medium 1 due to wind pressure can be suppressed.

In addition, the thickness of the portion in which the side surface side holding portion 3B is formed in the side curling portion 3b is thinner than the thickness of the portion in which the one side side space holding portion 3A is formed in the one side side curling portion 3a. The thickness of the front side spacer holding portion 3B is thinner than the thickness of the one side spacer holding portion 3A. Thereby, the filter medium 1 is easily bent and used as described above, and deformation of the filter medium 1 due to wind pressure can be suppressed.

Further, the filter medium and the filter unit of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Further, the structure, method, and the like of the plurality of embodiments may be arbitrarily employed or combined (the structure or method relating to an embodiment may be used. Further, it is a matter of course, the structure, the method, and the like of the other embodiments are arbitrarily selected, and the structure or method of the various modifications described below can be arbitrarily selected and used in the structure or method of the above-described embodiment.

For example, in the above embodiment, the curling portions 3a and 3b are formed to intersect the bent portion 1a. However, the present invention is not limited thereto, and as shown in FIG. 5, only the gap holding portions 3A, 3B may be formed. The portions constitute the curled portions 3a', 3b'.

Further, in the above-described embodiment, the plurality of the interval holding portions 3 are formed at intervals along the bent portion 1a. However, the present invention is not limited thereto, and may be integrally formed along the bent portion 1a.

Further, in the above-described embodiment, the filter medium 1 is constituted by the filter material 2 composed of the porous layer 2a and the base layer 2b. However, the filter medium 1 is not limited thereto, and as an example, only the porous layer may be used. The filter material formed by 2a. Further, in the above embodiment, the filter material 2 is formed of a plurality of porous layers 2a. However, the present invention is not limited thereto, and the filter material may be formed of a single porous layer 2a and the base layer 2b.

Example

Hereinafter, embodiments of the invention will be described.

<Production of Filter Media>

Porous sheet

A PTFE sheet was used as the porous sheet. Specifically, 20 parts by weight of a liquid lubricant (dodecane) was added to 100 parts by weight of PTFE fine powder (Fluon CD-123, manufactured by Asahi ICF Fluoropolymer Co., Ltd.) to form a paste mixture. Also, the mixture is prepared to be formed into a rod shape. Then, as in the foregoing embodiment, by The preliminary molded body was supplied between a pair of roll members and rolled to form a long piece (thickness: 200 μm). In addition, the long strips are stretched 11 times along the long direction in an environment of 200 ° C, and 25 times in the width direction orthogonal to the long direction in an environment of 80 ° C, thereby obtaining Unfired PTFE sheet.

The obtained PTFE sheet was fired at 400 ° C using a hot air generating furnace. The calcined PTFE sheet had an average pore diameter of 0.6 μm, a thickness of 16 μm, an average fiber diameter of 0.08 μm, a collection efficiency of 99.999%, and a pressure loss of 160 Pa. The pressure loss and the collection efficiency are obtained by the following methods.

2. Ventilation film

An air-permeable sheet (Eleves S030WDO, manufactured by Unitika Co., Ltd.) which is formed into a rectangular shape in one direction is used.

3. Production of filter materials

The porous sheet is such that the porous sheet is slightly parallel to the longitudinal direction of the air-permeable sheet in the two-area layer of the air-permeable sheet, and is transported between a pair of roller members (the heat roller and the support roller), and the porous sheet and the porous sheet are The air permeable sheet will be heat sealed and bonded. Thereby, the filter material 2 (width L2: 580 mm) shown in Fig. 2 was produced. The filter material 2 had a pressure loss of 170 Pa, a collection efficiency of 99.999%, and a thickness of 0.32 mm.

<pressure loss>

One side of the test sample (obtained porous sheet of filter material or 2), by a pressure gauge (pressure meter), measured with a test sample of: a gas permeable been disposed in an annular holder (effective area of 100cm ²⁾ The pressure difference on his face. Further, the permeation flow rate was 5.3 cm/sec, and the pressure difference was measured at 8 points of the test sample. The sum of the obtained measurement results is the aforementioned pressure loss.

<Capture efficiency>

A gas containing about 109/L or more of polydisperse dioctyl phthalate (DOP) is passed through a test sample which has been placed on a circular stent (effective area: 100 cm ² ) (the obtained porous sheet or filter material) 2). Further, the DOP concentration of the gas that has passed through the test sample is measured by a particle counter. Moreover, the collection efficiency (%) was calculated using the following formula (1). In addition, the permeation flow rate was 5.3 cm/sec. The DOP particles are in the range of 0.1 to 0.2 μm.

Collection efficiency (%) = {1 - (downstream concentration / upstream concentration)} × 100... (1)

<Examples 1 and 2>

= filter media =

After the obtained filter material 2 is pleated, as shown in FIG. 3, the filter material 1 is produced by forming the one side curling portion 3a and the other side curling portion 3b. The obtained filter medium 1 had a length L1 of 580 mm, a width L2 of 580 mm, a height L3 of 35 mm, and an average number of pleats of eight. The adhesive (hot melt adhesive) for forming each of the bead portions 3a and 3b was Macromelt 6202 (polyamide) manufactured by Henkel Corporation. Further, the ratio of the mass of the one side side bead portion 3a with respect to the mass of the side curling portion 3b (the ratio of the curling surface) is shown in Table 1 below. Further, the calculation of the ratio in the hemming table is performed by the following formula (2).

The ratio of the curling table = the mass of one side curling portion 3a / the quality of the side curling portion 3b... (2)

The mass of the one side curling portion 3a and the other side curling portion 3b was measured as follows. Specifically, first, the mass of the test piece (1.0 m ² ) taken from the filter medium 1 was measured. Further, the test piece was heated, and the quality of the test piece when one side side bead portion 3a (or the other side side bead portion 3b) was removed was measured. Moreover, the mass of the one side side beading part 3a (or the other side side beading part 3b) was calculated from the difference in quality before and after heating of the test piece.

= filter unit =

The filter medium 1 is housed inside the frame X (having an inner dimension of 580 mm × 580 mm, an outer dimension of 610 mm × 610 mm, and a thickness of 80 mm), and the sealing frame X is sealed by a two-liquid epoxy filler material. Filter the gap of the filter material 1. Thereby, the filter unit 10 as shown in FIG. 4 is produced. In addition, the two-liquid epoxy caulking material was mixed with Henkel's Macroplast 8104MC-18 and Macroplast UK5400 in a ratio of 3:1.

The filter medium 1 accommodated in the frame X is formed to be bent at both end portions in the direction of the length L1, and the field on the center side is located on the side of the opening portion X3 from the both end portions. In addition, the radius (bending radius) of the arc formed by the apex portions of the respective bent portions 1a constituting the projection side on the one side of the filter medium 1 is shown in Table 1 below.

= pressure resistance test =

In the central portion of the filter medium 1 in the obtained filter unit, a load is applied from the bulging side of both end portions in the length L1 direction. At this time, the displacement amount (displacement amount in the load direction) of the central portion of the filter medium 1 was measured. The method of applying a load is a method of placing one or more scales (□ 137 mm, 10 kg) in the central portion of the filter medium 1 .

<Comparative Example 1>

Each of the bead portions 3a and 3b is formed such that the ratio of the curling table is 0. Further, the amount of deformation was measured under the same conditions as in Example 1 except that the filter medium 1 was housed in the frame X without being bent. The amount of deformation is shown in Table 1 below.

<induction>

Comparing the respective examples with the comparative example 1, it can be seen that the deformation amount of each embodiment with respect to the load is small. In other words, in the respective embodiments, the filter medium 1 is formed in a curved state, and the rigidity of the filter medium 1 is increased with respect to the load from the center side bulging side of the filter medium 1, so that the deformation of the filter medium 1 can be suppressed. .

Further, by comparing Example 1 with Example 2, it can be seen that the bending radius is reduced by increasing the ratio of the curling surface. In other words, when the ratio in the curling table is increased, the difference between the interval between the flat plate portions 1b on one surface side of the filter material 2 and the interval between the flat plate portions 1b on the other side of the filter material 2 increases. Therefore, the filter medium 1 can be more easily bent, and the bending radius can be reduced. Thereby, since the rigidity of the filter medium 1 as described above can be improved, it can be seen that the deformation of the filter medium 1 is more effectively suppressed.

1‧‧‧Filter media

2‧‧‧ Filter material

3A‧‧‧One side spacer

3B‧‧‧He side interval keeping

10‧‧‧Filter unit

F‧‧‧Circulation direction

X‧‧‧ frame

X1‧‧‧ opposite wall

X2‧‧‧ Link wall

X3‧‧‧ openings

XL1‧‧ interval

XR‧‧‧ interior space

Claims (3)

A filter filter material comprising: a plurality of bent portions formed by bending a material of a filter material into a pleat shape, wherein the filter material is capable of trapping particles contained in the filtered gas; and the plurality of flat plate portions are in addition to the curved material of the filter material The regions other than the folded portion are disposed to face each other; and the plurality of spacers are formed between the flat portions of the one side of the filter material and the other side of the filter material to maintain the interval between the adjacent bent portions; The space-retaining portion is formed by joining a flat side portion which is formed by applying an adhesive to one surface of the filter material, and is formed by bonding the one side curling portion to the flat surface portion, and The side curling portion is formed by applying an adhesive to the other side of the filter material, and the one side curling portion and the front side curling portion are formed on the protruding side of the bent portion of the filter material. The thickness of the portion in which the spacer portion is formed in the side curling portion is made thinner than the thickness of the portion in which the spacer portion is formed in the one side curling portion, so that the filter medium is configured to be The foregoing Among the spacer holding portions formed on both surfaces of the material, the thickness of the surface-side spacer portion formed on the other side of the filter material is thinner than the thickness of the one-side spacer portion formed on one surface side of the filter material. The filter medium is filtered and bent to have a bending radius of 290 mm or more and 1200 mm or less. The filter medium according to claim 1, wherein the thickness of the portion where the space holding portion is formed in the one side curling portion is 20% or more and 80% or less of the thickness of the portion where the space holding portion is formed in the side curling portion. A filter unit configured to accommodate the filter medium in a housing that accommodates the filter medium of claim 1 or 2, wherein the frame includes an opening that allows the filtered gas to flow into the interior, and the filter medium is bent A region on the center side of the both end portions of the long direction is located on the side of the opening, and is housed in the casing.