JPH09290116A - Air filter of low pressure loss - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air filter with a low pressure loss and the high gaseous impurity-removing efficiency by causing the wavy or crest/trough-type ridge line of a separator of a porous material to cross the flow direction of a processing air at an angle in an air filter. SOLUTION: A wavy or crest/trough-type separator 108 is alternately laminated almost in parallel between sheet-like filter materials 106, in a space formed in an outer frame opened in the flow direction 102 of a processing air to obtain an air filter. In this case, this separator 108 is arranged in such a manner that its wavy or crest/trough-type ridge lines 120, 122 cross the flow direction 102 of the processing air at an angle. In addition, the separator 108 is constituted of a porous material or a meshy material. Under this constitution, the possibilities are increased that the processing air may pass through the porous part or the network of the separator 108. In this case, a turbulence is generated in the air current and gaseous impurities easily come into contact with the filter material to improve the gaseous impurity removing efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low pressure loss type air filter, and more particularly to an air filter for removing a trace amount of impurity gas in clean room air used in manufacturing precision electronic parts such as VLSI and liquid crystal substrates. is there.

[0002]

2. Description of the Related Art In recent years, with the progress of ultra-miniaturization of semiconductor devices, gaseous impurities (organic substances, acids, alkalis) that cannot be removed by conventional HEPA filters and ULPA filters.
Etc. are beginning to adversely affect yield. It is known that these gaseous impurities are generated in various forms such as invasion from the outside air, leakage of chemicals used in a clean room, degassing from clean room constituent members.

To remove these gaseous impurities, so-called chemical filters composed of activated carbon-based adsorbents and ion-exchange fibers are widely used. Since such a chemical filter is usually used in combination with a fine particle removal filter such as a HEPA filter or an ULPA filter, in order to secure a predetermined amount of blown air without increasing the load on the fan or blower that is the power source, A structure with low pressure loss is required.

As a low pressure loss type chemical filter,
In addition to the filter material having a honeycomb structure to improve the air circulation performance, as shown in FIG. 8, the outer frame 4a is opened so as to open in the flow direction of the treated air (the direction indicated by the white arrow 2 in the figure). An air filter having a structure in which 4b, 4c, and 4d are assembled, and a sheet-shaped filter material 6 having a physical or chemical adsorption action and a separator 8 are alternately laminated in substantially parallel to the air circulation direction 2 in the internal space thereof. Are known.

As the separator 8 of the air filter shown in FIG. 8, a plate-like material having a certain degree of rigidity such as a metal foil is folded into ridges and valleys as shown in FIG. Alternatively, a corrugated separator 12 having a corrugated structure as shown in FIG. 10 is used. As shown in FIG. 9, the ridge / valley separator 10 is formed with a fold line 10a on the ridge side and a fold line 10b on the valley side, and the corrugated separator 12 has a fold line as shown in FIG. A bending line 12a that connects the tops and a bending line 12b that connects the bottoms appear, and the folding line that appears in the peak-valley separator and the bending line that appears in the corrugated separator are the arrangement direction of the separator according to the present invention. Since this is an important factor for determining, the fold line and the bend line are collectively referred to as a ridge line in this specification. However, these terms are adopted for convenience in order to simplify the description of the present invention and facilitate understanding of the contents of the present invention, and the technical scope of the present invention appearing in the claims is: The method is not limited to such usage, and should be determined based on the technical contents described in the specification and drawings that can be easily understood by those skilled in the art.

Now, in the conventional low pressure loss type air filter shown in FIG. 8, as shown in FIG. 11, the ridge line 14 of the separator 8 is arranged in substantially the same direction as the air flow direction 2,
The pressure loss is reduced. That is, according to such a configuration, the separator 8 itself does not become a resistance to the air flow, so that the treated air smoothly passes through the air flow path formed by the separator 8 and the sheet-shaped filter material 6
In contact with the gaseous impurities are effectively removed.

Further, as in the air filter described in JP-A-7-171327, by using a porous plate or a mesh material for the separator, the air flow around the separator is disturbed and the air to be treated and the sheet are treated. Some of them promote the contact with the filter material to improve the removal efficiency. However, according to such a configuration, although it is possible to disturb the air flow in a limited range around the separator,
In reality, most of the air flow passes through the space with low resistance other than the porous part of the separator and the mesh (that is, the original air flow path formed by the separator surface), so the air flow is not disturbed so much and removed. Efficiency cannot be dramatically increased.

Furthermore, when the sheet-shaped filter material 6 and the separator 8 are laminated, if the peaks and valleys of the adjacent separators 8a, 8b and 8c overlap each other as shown in FIG. Alternatively, during use, FIG.
As shown in (b), the separator may bite into the sheet-shaped filter materials 6a and 6b. In particular, when the material of the sheet-shaped filter materials 6a and 6b is soft, the biting phenomenon is remarkable. As a result, the separators 8a, 8b, 8c and the sheet-shaped filter materials 6a, 6b
The pitch of the air flow formed between the sheet-shaped filter material and the adjacent sheet-shaped filter materials 6a and 6b is not uniform.
There is a problem that the particles adhere to each other and the air velocity distribution in the filter surface and the removal performance of the gaseous impurities tend to vary.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of a conventional low pressure loss type air filter, and an object thereof is to suppress the pressure loss of the filter while keeping it low. It is possible to increase the chances of contact between the air and the filter, and thus to significantly improve the efficiency of removing gaseous impurities. It is possible to effectively avoid the situation where the pitch of the filter becomes non-uniform. Therefore, it is possible to prevent variations in the wind velocity distribution and the removal performance of gaseous impurities within the filter surface for each product or before and after use for a predetermined period. It is possible to reduce the amount, and moreover, it is possible to obtain the above excellent effects without complicating the manufacturing and the structure as compared with the conventional product.
A new and improved low pressure drop air filter is provided.

[0010]

In order to solve the above-mentioned problems, according to the present invention, the sheets are provided in the spaces formed in the outer frames (104a to 104d) which are open in the flow direction (102) of the process air. The filter material (106) and the corrugated or peak-valley separator (108) that forms a flow path for the processing air between the adjacent sheet-shaped filter materials (106) are disposed substantially in the flow direction (102) of the processing air. A low pressure loss type air filter (100) is provided, which is formed by alternately stacking parallel air filters. In this low pressure loss type air filter, the corrugated or ridged valley (120, 122) of the separator (108) has an angle with the flow direction (102) of the treated air as described in claim 1. It is arranged so as to intersect with each other and is composed of a porous material or a mesh material. With this configuration, it is possible to dramatically increase the chances that the treated air passes through the porous portion and the mesh of the separator, and at that time, the air flow is agitated, and the gaseous impurities easily come into contact with the filter material. As a result, the efficiency of removing gaseous impurities is significantly improved.

The separator (108) further comprises a corrugated or ridged valley (120,
122) and the flowing direction (102) of the treated air are different from each other between the adjacent separators (108), and more preferably, the corrugated or ridge-valley shape is defined as described in claim 3. If the ridges (120, 122) are arranged so as to be line-symmetric with respect to the flow direction (102) of the treated air between the adjacent separators (108), as in the conventional air filter, between the adjacent separators, Since the peaks or valleys do not overlap, the separator cuts into the adjacent sheet-shaped filter material,
It is possible to effectively avoid a situation in which the pitch of the air flow paths becomes uneven.

A sheet-shaped filter material may be used as in claim 4.
As described in (3), if a chemical filter that removes the gas to be removed contained in the process air by physical or chemical adsorption is used, the gaseous impurities can be removed simply by bringing it into contact with the process air. The air filter can be configured.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a low pressure loss type air filter according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic exploded view of a low pressure loss type air filter 100 according to the present invention. As shown in the figure, the low-pressure drop air filter 100 has aluminum outer frames 104a, 104b, 104 so as to open in the flow direction of the process air (the direction shown by the white arrow 102 in the figure).
c and 104d are assembled, and the sheet-shaped filter material 106 having a physical or chemical adsorption action and the separator 108 are alternately laminated in the inner space thereof substantially parallel to the air circulation direction 102. The outer shape and dimensions of the air filter 100 can be arbitrarily designed according to the installation space, but in the example shown in the figure, for example, 27
With a substantially rectangular structure of 0 mm x 270 mm x 150 mm,
The opening size of the filter can be 240 mm × 240 mm.

As the sheet-like film to be used, it is possible to use various chemical filter materials capable of physically or chemically adsorbing and removing gaseous impurities in the treated air. A commercially available synthetic fiber non-woven fabric, a material that has been subjected to a chemical treatment such as graft polymerization for imparting an ion exchange function, for example, a basis weight of 50 to 500 g / m 2, a thickness of 0.2 to 5.0 mm, and a void. A rate of 50 to 95% can be used. In the illustrated example, a polyolefin-based nonwoven fabric having a sulfone group as an ion exchange group is used. As the chemical filter, polystyrene, polyvinyl alcohol, polyacryl, polyamide, polyphenol, polyethylene, a cation exchange group in a base polymer such as cellulose, for example, a sulfonic acid group, a phosphonic acid group, a carboxylic acid group or the like, an anion exchange group, for example, A sheet-shaped material such as a non-woven fabric having an ion-exchange function introduced with a primary to tertiary amino group or a quaternary ammonium group, activated carbon fibers or acids such as phosphoric acid, potassium carbonate, potassium permanganate, etc. It is possible to use a sheet in which an alkaline substance or an oxidizing substance is attached and which is processed into a sheet.

The separator 10 of the air filter shown in FIG.
As shown in FIG. 5, it is possible to use a machined aluminum-made expanded metal having a mesh structure as shown in FIG. 5, for example, a mesh size of 10 mm.
A mesh of × 20 mm and a line width of 0.8 mmW × 0.5 mmt is folded into ridges and valleys as shown in FIG. 9 (ridge / valley separator), or is bent into a corrugated shape as shown in FIG. Separator) can be used.
The height of the separator that determines the air flow path formed between the adjacent sheet-shaped filter material can be arbitrarily designed according to the amount of treated air, pressure loss, etc.
In the illustrated example, it can be about 4.0 mm. Although the mesh-shaped separator is used in the illustrated example, the present invention is not limited to this example. According to the present invention, as a separator material, it has rigidity to such an extent that an adjacent sheet-shaped filter material can be supported and an air flow path can be formed between them, and an air flow on the separator surface with a low pressure loss. Various structures can be used as long as they can pass through. For example, as in the above-described example, in addition to the expanded metal mesh, a mesh-shaped mesh in which fine wires are woven, a perforated plate, or the like can be used.

Next, referring to FIGS. 2 to 4, the structure of the air filter according to the present invention, particularly the arrangement structure of the separators, will be described.

FIG. 2 is an explanatory view showing a part of the air filter in an enlarged manner. Strongly acidic cation exchange fiber nonwoven fabrics 106a, 106b and 106c and separators 108a and 108b having a thickness of 0.6 mm are alternately laminated. The structure shown is shown. In the illustrated example, the separator 108 (108
As a and 108b), a ridge-valley separator is used, and the ridge lines of the mountain portions are indicated by dotted lines 120a and 120b, and the ridge lines of the valley portions are indicated by alternate long and short dash lines 122a and 122b. Then, according to the present embodiment, the separator 1
The ridge lines 120a, 120b and 122a, 122b of 08 and the flow direction 102 of the processing air are arranged so as to intersect each other at an angle (for example, 15 degrees). As a result, as shown in FIG. 3, the air flow direction (direction from the front to the back of the paper)
The air flow flowing along the 102 passes through the mesh of the separator 108, the stirring and mixing of the air flow occur, and the strong acid cation exchange fiber nonwoven fabrics 106a, 106b,
In contact with 106c, cationic gaseous substances such as ammonia and amine are removed by chemical or physical adsorption. In that case, according to the present embodiment, compared with the conventional air filter configured so that the ridge line of the separator and the air flow direction are substantially parallel to each other, according to the present embodiment, the opportunity for the air flow to pass through the mesh is dramatically increased. Therefore, turbulent flow is likely to occur, and the chances of contact between the treated air and the above strongly acidic cation exchange fiber nonwoven fabrics 106a, 106b, 106c are increased,
The removal efficiency of cationic gaseous substances is also increased. Further, according to the present embodiment, since the separator 108 is made of the mesh material or the perforated plate material, it does not increase the pressure loss of the air flow passing through the air filter. An air filter with high removal efficiency and low pressure loss can be obtained.

Further, according to the present embodiment, the angle formed by the ridgeline of the separator and the flow direction of the treated air is different between the adjacent separators.
Referring to FIG. 2, the ridge lines 120a and 122a of the separator 108a and the ridge lines 120b and 122b of the adjacent separator 108b are the flowing directions 102 of the treated air.
Against different directions. The configuration of the ridgelines 120 and 122 of the separator 108 can be more easily understood with reference to FIG. That is, when the flow direction 102 of the treated air is from the upper side to the lower side of the paper surface, the separators 108a and 108c
Ridge lines 120a, 122a, 120c, 122c of the separators 108b, 122b, 122b, 12 of the separators 108b, 108d.
0d and 122d are configured to flow from the upper left side to the lower right side of the drawing. That is, in the illustrated example, the respective ridge lines of the separators are configured to be line-symmetric with respect to the flow direction of the treated air in the adjacent separators. And according to this structure, the ridgelines of the adjacent separators do not overlap with each other. Therefore, the peaks and valleys of the adjacent separators do not overlap each other.
As in the conventional example shown in (b), it is possible to effectively avoid the situation where the separator bites into the adjacent sheet-like film and the pitch of the air flow paths becomes uneven.

Although the preferred embodiments of the low pressure loss type air filter according to the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples.
It is obvious to those skilled in the art that various changes and modifications can be conceived within the scope of the technical idea described in the claims, and those are naturally within the technical scope of the present invention. It is understood that it belongs.

For example, in the above embodiment, the ridge lines 120 and 122 of the adjacent separators 108 are arranged so as to form the air flow direction, but the present invention is not limited to this example, and as shown in FIG. Separators 208a-208d
It is also possible to employ a structure in which the ridgelines 220a to 220d and 222a to 222d are arranged so that the angles thereof are the same as the air flow direction. According to this configuration,
Although the improvement in the performance of maintaining the uniformity of the air flow path is inferior to that of the previous embodiment, the treated air is separated by the separator 20.
The chances of passing through the porous portions or meshes of 8a to 208d are dramatically increased, the agitation of the air flow is promoted at that time, and the efficiency of removing gaseous impurities can be dramatically improved.

Further, as the filter member structure, in the above embodiment, a structure in which a single sheet of filter material and a separator are laminated is adopted, but the present invention is not limited to this example, and as shown in FIG. By weaving the long separator 302 into the
It is also possible to configure the filter by making the angles of the ridgelines of 02b symmetrical and inserting the filter material 304 between them. With such a configuration, it is possible to obtain the same effect as that of the filter according to the above embodiment.

[0023]

According to the present invention, a mesh material or a perforated plate material is used as the separator, and the peaks and valleys of the separator and the ridges of the waves make an angle with the air flow direction. It is possible to dramatically increase the chance of contact with the particulate filter material and effectively remove the gaseous impurities contained in the process air without increasing the pressure loss.

Further, according to the present invention, the peaks and valleys of the adjacent separators and the ridgelines of the waves are arranged so as to form different angles with respect to the air flow direction, and the peaks or valleys do not overlap with each other. It is possible to avoid the situation where the pitch of the air flow becomes uneven and cuts into the sheet-shaped filter material, and it is possible to provide a low pressure loss type chemical filter with uniform product quality. .

[Brief description of drawings]

FIG. 1 is an exploded view showing a schematic configuration of a low-pressure loss type air filter according to the present invention.

FIG. 2 is a partially enlarged schematic view showing a laminated structure of a filter and a separator of the low pressure loss type air filter shown in FIG.

FIG. 3 is a front view of the laminated structure shown in FIG.

FIG. 4 is an explanatory view showing an arrangement structure of a separator of a low pressure loss type air filter according to the present invention.

FIG. 5 is an explanatory view showing a mesh structure of a low pressure loss type air filter according to the present invention.

FIG. 6 is an explanatory view showing still another arrangement structure of the separator of the low-pressure loss type air filter according to the present invention.

FIG. 7 is an explanatory diagram showing still another member configuration of the low-pressure loss type air filter according to the present invention.

FIG. 8 is an exploded view showing a schematic configuration of a conventional low pressure loss type air filter.

FIG. 9 is a schematic diagram showing a schematic configuration of a mountain-valley separator used in a conventional low-pressure loss air filter.

FIG. 10 is a schematic diagram showing a schematic configuration of a corrugated separator used in a conventional low pressure loss type air filter.

FIG. 11 is an explanatory diagram showing an arrangement structure of a separator of a conventional low pressure loss type air filter.

12A and 12B are explanatory views showing a laminated structure of a conventional low pressure loss type air filter, in which FIG. 12A shows a normal state and FIG. 12B shows a state in which a separator digs into a filter material.

[Explanation of symbols]

 100 Low Pressure Loss Type Air Filter 102 Air Flow 104 (104a to 104d) Outer Frame 106 Sheet-like Filter Material 108 Separator 120 Ridge Line 122 Ridge Line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takaki Yoshida 3-35-15 Nodai, Zama City, Kanagawa Prefecture (72) Takao Okada 2-16-13 Tamagawa Gakuen, Machida City, Tokyo

Claims (4)

[Claims] 1. A corrugated shape or a mountain trough that forms a sheet-shaped filter material and a flow path of the treated air between adjacent sheet-shaped filter materials in a space formed in an outer frame that opens in the processing air flow direction. In a low pressure loss type air filter formed by alternately laminating a mold separator and the processing air in a direction substantially parallel to the flowing direction of the processing air, the separator has an ridge line of a corrugated or ridge-valley angle with the flowing direction of the processing air. A low pressure loss type air filter, wherein the separator is made of a porous material or a mesh material. 2. The low angle according to claim 1, wherein an angle formed by a corrugated or ridged valley line of the separator and a flow direction of the treated air is different between the adjacent separators. Pressure loss type air filter. 3. The low pressure according to claim 1, wherein the corrugated or mountain-valley ridges of the separators are line-symmetric with respect to the flow direction of the treated air in the adjacent separators. Loss-type air filter. 4. The sheet-shaped filter material is a chemical filter that removes a gas to be removed contained in the process air by a physical or chemical adsorption action, according to any one of claims 1 to 3. Low pressure loss type air filter described in.