JP2000051635A - Chemical filter unit and gas purifying system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong a life of a filter unit by lowering a pressure loss and increasing an adsorbing capacity of filter media to a specific value or over a method wherein an air to be treated is allowed to pass through a gas circulating passage provided from a gas inlet to a gas outlet between adjoining fiber sheets of the filter media. SOLUTION: Filter medium 5 comprises plural sets of fiber sheet laminates. That is, a corrugate processed product comprising a fiber sheet 6 for a center core and a fiber sheet 7 for a liner is formed from a set of fiber sheets, and a gas circulating passage 8 is formed on a comparted manner between both sheets 6, 7. Besides, a filter unit comprising a filter media storing box and a cover box, and an opening for circulating a gas is respectively arranged to those front surfaces. Then, a rear face metal net and a rear face non-woven fabric are successively stored in the media storing box prior to storing the filter media, and a front surface non-woven fabric and a front surface metal net are successively stored in the filter media storing box prior to equipping the cover box thereto. Herein, a total adsorbing capacity of the filter media to be filled in a unit volume of the filler is set at 300 eq/m3 or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical filter unit and a gas cleaning system, and more particularly to a gas (particularly air) supplied to a clean room, a clean booth, a clean bench, etc. (hereinafter referred to as a clean closed space). For chemical contaminants in the above), use ion exchange or charge adsorption mechanism
The present invention relates to a high-precision chemical filter unit and a gas cleaning system which can be reduced / removed to a very low concentration level and which can be used for a long period of time with a low pressure loss of flowing gas to be treated.

[0002]

2. Description of the Related Art In recent years, the necessity of a clean closed space such as a clean room has been rapidly increasing in the fields of electric and electronic industries, biochemical fields and the like. As the level of each manufacturing technology has improved, so has the demand for cleanliness, and the analysis technology that has been associated with it has dramatically improved in the past few years. The need for their removal has been recognized.

[0003] Up to now, gas purification in a clean closed space has mainly been carried out by removing fine particles typified by a HEPA filter, and the removal of solid fine particles has been managed to a limit.

However, when the air in the clean enclosed space passes through the filter and is circulated, the mist and gasified chemical substances contained in the air are rather concentrated and higher than the concentration level of the outside air. It has been found that even chemical substances exhibiting values are present. This is because, in the conventional air cleaning, the necessity of removing chemical substances contained in the air is not recognized, and therefore, the cleaning device does not have such a function.

[0005] In recent years, the necessity of removing such chemical substances has been recognized in the field of electronics industry for manufacturing precision products represented by VLSI. Among them, especially in the photolithography process, the phenomenon that directly deteriorates the product yield due to the presence of these chemicals has been identified, necessitating the development of a technology for removing chemicals using a new filter with a completely different concept from HEPA filters. Came to be recognized.

[0006] Among them, substances that have become particularly problematic are ammonia and amines such as organic amines.
Although very few examples have been identified of chemicals that are process inhibitors, it has been clearly identified that the presence of ammonia, due to its unique phenomena, such as haze and dielectric breakdown, significantly reduces product yield. Was. In the process of manufacturing a chemically amplified resist in the photolithography process, a device is formed by a mechanism in which protons are generated as a chemically amplified agent in a region irradiated with light to promote dissolution in a developing solution. Therefore, if ammonia is present in the atmosphere, protons are neutralized and disappear, and dissolution of this portion in the developer is inhibited. This causes a very serious trouble called T-TOP destruction. It is known that this phenomenon occurs when the ammonia concentration in the air is as low as several ppb. To solve this problem, the ammonia concentration in the purified air must be reduced to 5 ppb.
It must be less than pb. The ammonia level in the air to be treated varies depending on the location, but is usually several tens to several hundreds p.
Therefore, a cleaning system which can be reduced by pb was desired.

Here, JP-A-1-317512 discloses a method of removing sea salts (including ammonia) from air by passing air through a filter medium containing ion-exchange fibers. However, this technology is capable of adsorbing and removing ammonia to an extremely low concentration (ppb order), a technique for reducing the pressure loss of a filter made of the filter material, and a method for measuring the filter life per unit volume, which means the service life of the filter. There is no description of a method for increasing the adsorption capacity of the compound.

Japanese Patent Application Laid-Open No. 61-138543 discloses a filter medium obtained by corrugating a laminated sheet in which a sheet made of pulp is superposed on both sides of a sheet having ion exchange fibers. . But,
This filter medium is used in a method (cross-flow method) in which gas flows from the front sheet surface to the rear sheet surface constituting the filter material. In addition, there is no description about a method for reducing the pressure loss of a filter made of a filter medium or a method for increasing the adsorption capacity per unit volume of the filter medium, which means the service life of the filter.

Further, Japanese Patent Application Laid-Open No. 60-183022 discloses a filter made of ion exchange fibers for capturing mutagenic substances in the air. But,
Although this filter has very high performance as a material, it is used as it is in a planar state without any description in its filter structure (cross-flow), so a filter design with extremely high pressure loss cannot be achieved. Not get. For this reason, a material configuration taking into account the permeation flux of the filter is adopted. In addition, there is no description of a technique for increasing the adsorption capacity per unit volume of the filter medium, which means the service life of the filter.

Japanese Patent Application Laid-Open No. Hei 8-24564 describes a unit incorporating a sheet made of ion exchange fibers. However, this method employs a method in which the ion-exchange fibers are formed into a sheet such as a nonwoven fabric, overlapped with a spacer interposed therebetween, and filled in a tower. this is,
This is because in order to secure a practical level of pressure loss while utilizing the adsorption performance of the sheet-like ion exchange fiber, it is necessary to create a certain space using a spacer in order to prevent the filter medium from being thickened. However, this reason since the amount of filter media is significantly limited by the total adsorption capacity decreases to be filled surely into a unit volume, resulting in life of the unit had to become short. Conversely, if the service life is to be extended, the volume of the unit will be very large, and the fan capacity for blowing must be very large, and the clean room system itself must be changed. There was no current situation.

Therefore, the prior art cannot respond to the demands in the above field.

[0012]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a chemical filter unit and a gas cleaning system capable of meeting the above-mentioned demands. Provided is a chemical filter having a remarkably large adsorption capacity per unit volume as compared with conventional ones and having a very small pressure loss of a filter medium.

In order to solve the former problem, it is easy to increase the amount of the filter medium in a fixed volume, but this does not solve the latter problem. Conversely, if the amount of filter medium in a given volume is reduced, the latter objective is achieved, but the former problem is not solved.

The present invention makes it possible to simultaneously satisfy these contradictory filter characteristics, and at the same time solves the problems which the present problem has.

[0015]

Means for Solving the Problems In order to achieve the above object, the present invention comprises a filter medium formed by laminating a plurality of fiber sheets, and a frame accommodating the filter medium. In a chemical filter unit having an open gas inlet and a gas outlet opening on the other surface substantially opposed to the gas inlet, between the adjacent fiber sheets of the filter medium, from the gas inlet toward the gas outlet. A low pressure loss is made possible by employing a method of passing air to be treated through a gas flow passage (which allows gas to flow along the surface of the fiber sheet) provided at the same time, and at the same time, the adsorption capacity of the filter medium is reduced. Since it is 300 eq / m ³ or more, a chemical filter unit having a long life can be obtained.

Further, the gas cleaning system of the present invention comprises a production chamber and a gas purifier for supplying a clean gas from which chemical contaminants have been removed to the production chamber. It includes a filter unit.

In the present invention, the "clean closed space" refers to an internal space such as a clean room, a clean booth, a clean bench, etc., which means a space which is mainly shut off from the outside. A space for taking in the fluid to be treated is also included.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The chemical filter unit of the present invention is used for the purpose of adsorbing and removing chemical contaminants in a clean enclosed space, and is a high-performance filter that can sufficiently cope with the demands of the electronics industry. is there.

The most important point in the present invention is that the filter structure is composed of a filter material formed by laminating a plurality of fiber sheets and a frame material containing the filter material, and a gas flow opening on one surface of the support. A filter unit having an inlet and a gas outlet opening on the other surface substantially opposite to the inlet, wherein between adjacent fiber sheets of the filter medium, gas can flow along the surface of the fiber sheet. A gas flow passage is provided from the gas inlet to the gas outlet, and the adsorption capacity of the filter medium is 300 eq / m.
³ or more.

The gas flow path allows the gas to be treated to flow along the surface of the fiber sheet constituting the filter medium. This means that the flow of the gas to be treated to the filter medium is a parallel flow. By constructing this structure only with the filter medium fiber sheet, the adsorption capacity per unit volume of the filter medium can be increased by 300.
eq / m ³ or more, and the pressure loss of the filter medium can be reduced.

By adopting this parallel flow structure, when the average air velocity of the air to be processed that is passed through the gas inlet of the filter unit is 0.5 m / s, the filter medium having a depth of 70 mm in the direction of the gas flow passage is formed. It enables extremely low pressure loss of flowing gas of 3 mmAq or less.
When a cross-flow is applied to the surface of the filter medium as in a usual case, no matter how thin the filter medium is used, the pressure loss must be very large as compared with the parallel flow.

However, it is necessary to use a material having a high adsorption performance (adsorption speed) possessed by the filter medium itself in order to maintain excellent adsorption accuracy while aerating with a parallel flow. In the present invention, the filter medium is optional, but from the viewpoint of high adsorption rate and good shape retention, a filter medium made of activated carbon fiber chemically modified (for example, carrying phosphoric acid) or ion exchange fiber is used. preferable. Among them, it is particularly preferable to use a filter medium made of a polystyrene-based ion exchange fiber. Among them, it is most preferable to use a fiber having a structure in which a polymer in which an ion exchange group is introduced into crosslinked insolubilized polystyrene is structurally supported by a reinforcing polymer (for example, polyolefin).

Here, the main targets to be removed by the chemical filter unit of the present invention are amines such as ammonia and organic amines which make up 70% or more of the total adsorbed substances. Exists in gas form. It is preferable that a cation exchange group is introduced as the ion exchange group for adsorbing them, and an aminocarboxylic acid group such as a sulfonic acid group, a phosphonic acid group, a carboxylic acid group, and an iminodiacetic acid group is preferably used. The sulfonic acid group is more preferable from the viewpoint of the processing performance in the above.

The adsorption capacity according to the present invention is a calculation of how much a fine jersey gas having a plus jersey (mainly belonging to ammonia and organic amines) can be adsorbed in consideration of chemical equilibrium. Value. For example, in the case of activated carbon fiber carrying phosphoric acid, the maximum equilibrium amount when all the reactive groups are converted into salts can be determined from the total weight of phosphoric acid carried. Here, when the filter medium made of cation exchange fibers is used as described above, the cation exchange capacity is the adsorption capacity. The measurement method is arbitrary, but generally a method is used in which a filter medium sample is cut out, reacted in sodium hydroxide having a precisely determined factor, and the remaining liquid is subjected to neutralization titration.

Here, what is important in the present invention is that
It is to make the total adsorption capacity of the filter medium filled in the filter unit volume 300 eq / m ³ or more. In order to make this possible, it is necessary that the adsorption capacity of the adsorbent itself is large, but the balance between the filling method and the adsorption performance is important.

It is undoubtedly important to compactly fill a filter medium having as large an adsorption capacity as possible in a unit volume in designing a chemical filter unit.
In order to make this possible, for example, a filter filled with a material obtained by processing ion-exchange fibers into a uniform fiber sheet to form a three-dimensional structure can be mentioned. Three
In the three-dimensional structure, a gas flow passage penetrating from one surface of the filter medium to the other surface facing the filter medium is formed between adjacent fiber sheets.

Although the material used for the sheet is optional,
Among them, it is particularly preferable to use a paper made of a heat-sealing material together with the ion-exchange fiber to effectively form a three-dimensional structure only by heat and pressure. Here, the chemical filter unit of the present invention uses a three-dimensional structure made of these filter materials without using an adhesive or other reinforcing material / form retaining material.
It is preferable to be built in the frame material only by the compression filling pressure. This is very important for the total performance of the chemical filter unit. For example, it is obvious that a method in which a sheet-shaped filter medium is inserted using a shape-retaining material and a structure is formed and built using only the filter medium has a large filter medium ratio per unit volume. What is extremely important is that there is no concern about a small amount of gas (out gas) released from the adhesive, the reinforcing material, and the shape retaining material. In a clean enclosed space that requires the chemical filter unit of the present invention, the existing gas concentration level is a low concentration that is completely different from the normal space. In such an atmosphere, how much outgas is released from all the materials present therein becomes a very important problem. Of course, the same attention must be paid to outgas from a chemical filter used as an adsorbent. Under such circumstances, using an adhesive to process the filter medium or attach it to the frame material is likely to be a completely fatal drawback. Also, there is no concern about outgassing from other materials such as a shape retaining material and a reinforcing material, which is a very effective advantage.

In the present invention, there is no particular limitation on the three-dimensional structure using the filter medium. When the filter finally becomes a filter, basically any form can be used as long as the adsorption efficiency of the gas to be adsorbed and the pressure loss at that time can be achieved at a practical level. For example, a regular type such as a lattice type, a corrugated type, a honeycomb type, a cylindrical type and the like can be mentioned, but of course, the present invention is not limited thereto.

However, for the purpose of the present invention, among them, the one subjected to corrugation processing can increase the filling amount per unit volume, can be easily processed only by the process of thermocompression bonding, and can be used for filling the frame material. This is preferable because a solid product without gaps can be produced without an adhesive by applying a compression filling pressure. The corrugated product is formed by bonding a corrugated sheet (core) and a planar sheet (liner) and alternately stacking them to form a large number of small through holes.

The configuration is arbitrary, and there is no problem to add a contrivance such as increasing the number of cores or changing the height of the crest. Basically, it is only necessary to apply a corrugated process consisting of a liner and at least one core. As a method of producing a heat-fused corrugated product, a fiber sheet serving as a base material for the core is corrugated by passing the fiber sheet while being in contact with a roll having irregularities on the surface, and then a roll having a wavy shape on the core side, The corrugated crest of the core substrate is pressed and heated to the liner substrate in such a way that each fiber sheet is sandwiched between rolls having a flat shape on the liner side. In many cases, a method in which only a portion is melt-bonded is used, but the method is not particularly limited as long as a similar shape can be finally formed.

Finally, the chemical filter unit of the present invention is used for the purpose of adsorbing and removing chemical contaminants in a clean closed space, and it can be used in any place. It is most effective in being done. In addition, the use of chemically amplified resist, which is an urgent issue in the near future, that is, adsorption and removal of fine particles, mist, gas, etc. (more than 70% of which belongs to amines such as ammonia and organic amines) having a positive charge in the lithography process In the above, it is possible to provide a chemical filter unit capable of performing high-precision processing in which the concentration level of those contained in the processing air exiting the unit is reduced to the ppb order.

Examples will be shown below, but the present invention is not limited to these.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described. Of course, what is described below is an example, and the present invention is not limited to this.

FIG. 1 is an example of a fiber sheet used for forming a filter medium of the filter unit of the present invention. As shown in the figure, a fiber sheet 1 is formed by making short fibers 2 into paper, and is formed into a corrugated shape 3 after paper making. A plurality of the fiber sheets 1 are vertically stacked to form a filter medium. In the filter medium, a gas flow passage 4 is formed between each fiber sheet 1. FIG. 2 shows an example of a filter medium used in the filter unit of the present invention. The filter medium 5 is composed of a laminate of a plurality of sets of fiber sheets. One set of fiber sheets is a core fiber sheet 6.
And a fiber sheet 7 for a liner. A gas flow passage 8 is formed between the core fiber sheet 6 and the liner fiber sheet 7. FIG. 3 is another example of a filter medium used in the filter unit of the present invention. The filter medium 9 is composed of a laminate of a plurality of fiber sheets 10. Each fiber sheet 10 has a honeycomb structure and is laminated. The hollow portion of the honeycomb forms a gas flow passage 11. FIG. 4 is another example of a filter medium used in the filter unit of the present invention. The filter medium 12 is formed by continuously winding one fiber sheet 15 made of a corrugated product including the core fiber sheet 13 and the liner fiber sheet 14 from the center to the outside. . A gas flow passage 16 is formed between the core fiber sheet 13 and the liner fiber sheet 14.

Although not shown, any of the fiber sheets in FIGS. 1 to 4 is fixed to a frame member having a rectangular or cylindrical shape on the outer periphery, and a chemical filter unit to be described later with reference to FIG. 20.

FIG. 5 shows an example of the filter unit of the present invention.

The filter unit 20 has a filter medium storage box 22 in which the filter medium 21 is stored, and a lid box 23 which fits outside the filter medium storage box 22 after the filter medium 21 is stored in the filter medium storage box 22. Filter medium storage box 22 and lid box 2
Openings 24 and 25 through which gas flows are provided on the front surface of 3. Before the filter medium 21 is stored in the filter medium storage box 22, the aluminum wire mesh 2 is placed in the filter medium storage box 22.
6 and the back nonwoven fabric 27 are stored in this order. Next, the filter medium 21 is stored in the filter medium storage box 22 in a state of being pressed and compressed in the direction indicated by the arrow 28. Before the lid box 23 is attached to the filter medium storage box 22, the front non-woven fabric 29
And an aluminum front metal net 30 are stored in this order.
Movement of the aluminum front wire mesh 30 to the filter medium storage box 22
Indicated by arrow 31. Next, the lid box 23 is put on the filter medium storage box 22. The movement of the lid box 23 to the filter medium storage box 22 is indicated by an arrow 32. Both are fixed by a fixture (not shown). Here, an example of the filter unit of the present invention is completed. The filter medium storage box 22 having the opening 24 and the lid box 23 having the opening 25 form a support according to the present invention.

FIG. 6 is a schematic diagram of an ammonia gas aeration test apparatus employed in carrying out the following Examples and Comparative Examples. Reference numeral 42 denotes a fan for taking in outside air 41, and 43 denotes activated carbon filling for preliminarily filtering the outside air. Filter, 44 is H
EPA filter. On the other hand, 45 is an ammonia gas inlet provided in a conduit connecting these devices,
The mixed sample gas is mixed at a constant concentration in a gas mixing chamber 46 and can be sampled at a sampling port (upstream side) 47.

Reference numeral 48 denotes an attachment port of the chemical filter unit 20 shown in FIG. 5 according to the present invention, and the clean gas 51 filtered by the filter can be sampled at a sampling port (downstream side) 49. I have. On the other hand, the remaining gas is abandoned from the discharge port 50.

EXAMPLE (Ion-exchange fiber) A cut fiber is obtained by cutting a multifilament sea-island composite fiber [sea component polystyrene / island component polyethylene = 50/50 (16 islands)] into a 0.5 mm length. Was. One part by weight of the cut fiber was added to a commercially available cross-linking / sulfonation solution comprising 7.5 parts by weight of primary sulfuric acid and 0.07 part by weight of paraformaldehyde, followed by reaction at 90 ° C. for 4 hours. Next, a cation exchange fiber having a sulfonic acid group was obtained by treating with an alkali and then activating with hydrochloric acid. (Exchange capacity 3.0 meq / g-Na, water content 1.5). The exchange capacity was measured by the following method.

1 g of the cation exchange fiber was placed in 50 ml of 0.1 N sodium hydroxide, and shaken at 23 ° C. for 2 hours.
Weigh exactly 5 ml and calculate by neutralization titration.

Further, the cut fiber converted into Na type was sufficiently immersed in ion-exchanged water, dehydrated with a household centrifugal dehydrator, weighed (W), and kept in a dryer at 60 ° C. for 48 hours. After drying, the weight was measured (Wo) and the water content was determined by the following equation.

Water content = (W-Wo) / Wo (papermaking process) The above ion-exchange fiber and heat-fused fiber (trade name "Sophite N720": low melting point PET manufactured by Kuraray Co., Ltd.) and Manila hemp as a papermaking auxiliary material were mixed with 60: The mixture was mixed at a ratio of 20:20, paper was formed by a rotary filter cloth type large paper machine, continuously dried by a drum rotary dryer at 120 ° C., and wound up to obtain a fiber sheet made of ion exchange fibers. From the fiber sheet, a 3 cm square sheet sample was cut out, the sample was immersed in a sodium hydroxide solution in the same manner as in the case of the ion exchange fiber, and the ion exchange capacity per sample weight was measured. The ion exchange capacity is 1.5
meq / g.

(Corrugating Step) A roll (120 to 130 ° C.) having a corrugated surface shape, a fiber sheet for a core, and a liner are prepared by corrugating the fiber sheet made of the above ion-exchange fibers in a corrugating machine (single facer for 5th stage). The fiber sheet for the core and the fiber sheet for the liner 7 are heated by applying pressure between the rolls so that the fiber sheet for the core and the fiber sheet for the liner 7 are arranged in the order of the fiber sheet for use and the pressure roll having a flat surface shape. Pressure bonding, 2nd
The corrugated structure 5 shown in the figure was manufactured. From this corrugated structure, a 2 cm square sample was cut out, and the sample was immersed in a sodium hydroxide solution in the same manner as in the case of the ion exchange fiber, and the ion exchange capacity per sample weight was measured. The ion exchange capacity is 1.45
meq / g.

(Chemical Filter Unitization Step) The corrugated structure 5 was cut into a rectangular shape of 590 × 70 mm to form a sheet. The sheets were stacked and fitted into an aluminum frame material so as to be 590 x 590 x 70 mm to form a chemical filter unit.
The total weight of the filter medium filled in the filter unit was 6050 g. The total ion exchange capacity of this filter medium consisting of only the corrugated structure was indicated by the product of the weight of the filter medium and the ion exchange capacity, and was 8.8 eq.

From this, the ion exchange capacity per unit volume of the chemical filter was calculated to be 360 eq /
m ³ .

Filter media 5 in chemical filter unit
Are stacked so that the opening surface of the corrugated structure comes to the opening of the frame and the opposite surface thereof, and a gas flow passage 8 that allows gas to flow along the surface of the fiber sheet is provided with a gas flow passage from the gas inlet. It was provided towards the exit. Therefore,
The air to be processed flows in the direction of the parallel flow 8a.

Using this chemical filter unit, an experiment on ammonia adsorption performance was performed. The above-mentioned chemical filter unit is attached to the mounting port 48 of the test apparatus shown in FIG.
Standard air adjusted to pb) was ventilated. The surface wind speed of the ventilation was 0.5 m / s. When the pressure loss at that time was measured, it was 1.7 mmAq.

After a certain period of time, the gas before and after the chemical filter was sampled, and the result of measuring the ammonia concentration was analyzed by simulation.

In the sampling, the air flowing through the ventilation pipe 40 was pruned, and ammonia was dissolved in ultrapure water in a collection device called an impinger to collect. The analysis was performed by micro-analysis using ion chromatography.

As a precondition for the simulation, 10
A point at which the ppb ammonia gas was passed and the outlet concentration of the chemical filter became 1 ppb or more was determined as the life.

This is a value calculated from an example of a necessary condition of a clean closed space such as a clean room in the field of electronics industry. As a result of analysis using this, the life of the present chemical filter unit was 890 days. This result means that the present chemical filter unit can be used continuously for two years in an actual air purifying system for a clean closed space without replacement midway.

Comparative Example 1 Using the ion-exchange fiber and the fiber sheet prepared in exactly the same manner as in the example, the porosity in corrugation was changed to prepare the filter medium 5 shown in FIG. 590 x 5 vertical
A chemical filter unit having an ion exchange capacity per unit volume of 290 eq / m 3 was prepared by fitting the frame into an aluminum frame material of 90 × 70 mm in depth. Using the filter unit, the same experiment as in the example was performed.
As a result, the pressure loss decreased to 1.3 mmAq. However, although the high removal rate was maintained in the early stage of the experiment, the rate of decrease in the ammonia removal rate during the course of the experiment was large, and the simulation analysis showed that the filter life was 590 days. This number of days means that only one time / year of regular repairs is needed, and in the current chemical pollution collection system, all filters that have reached the end of their service life by the next regular repair are replaced in one year. .

Comparative Example 2 A polyolefin filament was formed into a non-woven fabric and then irradiated with an electron beam to form a graft base point. The ion-exchange non-woven fabric was converted into a cation exchange fiber by a reaction with a graph, and was made of aluminum wire. For a commercially available chemical filter unit (590 in width × 590 in height × 70 mm in depth) in which a spacer is arranged and filled in a frame material, the same experiment as in the example was performed. The ion exchange capacity per unit volume of this chemical filter is 278 eq
/ M ³ .

A simulation analysis of the results showed that the life of the chemical filter was 586 days, but the pressure loss was as high as 6.0 mmAq.

In the experiment, since the surface wind speed needs to be the same as that of the embodiment, it is necessary to change the capacity of the ventilation fan to be large in this chemical filter having a high pressure loss.

[0058]

According to the chemical filter of the present invention, it is possible to remove chemical contaminants in a clean closed space to a very low concentration level, and since the low pressure drop and the effect thereof are very long, the user side is required. It has become possible to clean at low cost.

By applying this chemical filter unit, the filter characteristics which have been used unsatisfactorily because of the drawback that the filter having a high adsorption capacity has a large pressure loss and the adsorption capacity is small when the pressure loss is reduced, are simultaneously satisfied. Can be done.

From this fact, it is very effective to apply the present invention to an air purifying apparatus in the field of the electronics industry for manufacturing a product typified by a super LSI which dislikes chemical contaminants.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a lattice filter medium of a chemical filter unit according to the present invention.

FIG. 2 is a perspective view of a corrugated filter medium of the chemical filter unit according to the present invention.

FIG. 3 is a perspective view of a honeycomb filter medium of the chemical filter unit according to the present invention.

FIG. 4 is a perspective view of a cylindrical filter medium of the chemical filter unit according to the present invention.

FIG. 5 is an exploded view of the chemical filter unit according to the present invention.

FIG. 6 is a schematic diagram of a filter test apparatus used in carrying out Examples and Comparative Examples.

[Explanation of symbols]

 1: fiber sheet 2: short fiber 3: corrugated filter medium 4: gas flow pipe 5, 9, 12: filter medium 6: fiber sheet for core 20: chemical filter unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D012 CA10 CB02 CG02 CG04 CH01 CK07 4F071 AA14 AA22 AB03 AF08C AF08Y AH02 FB05 FB07 FC03 FC06 FC11

Claims (9)

[Claims] 1. A gas inlet formed on one surface of a support, comprising a filter medium formed by laminating a plurality of fiber sheets and a frame material containing the filter medium, and another surface substantially opposed to the gas inlet. A gas flow outlet that is open to the gas filter, wherein between the adjacent fiber sheets of the filter medium, a gas flow passage that allows gas to flow along the surface of the fiber sheet extends from the gas inlet to the gas flow path. Provided toward the outlet and having an adsorption capacity of the filter medium of 300 eq / m ³
A chemical filter unit characterized by the above. 2. An average surface wind velocity of the gas flowing from the gas inlet to the gas outlet at the gas inlet surface is 0.5.
m / sec, depth 70 m in the direction of the gas flow passage
The chemical filter unit according to claim 1, wherein the pressure loss of the flowing gas caused by the filter medium of m is 3 mmAq or less. 3. The chemical filter unit according to claim 1, wherein the fibers constituting the fiber sheet are ion exchange fibers, and the adsorption capacity is the ion exchange capacity. 4. The method according to claim 1, wherein the filling of the filter material into the frame material is performed substantially only by the elastic force of the plurality of fiber sheets, and the filter material is fixed to the frame material. The described chemical filter unit. 5. A gas purifying apparatus comprising: a production chamber; and a gas purifier for supplying a clean gas from which chemical contaminants have been removed to the production chamber. A gas cleaning system comprising a chemical filter unit. 6. The gas cleaning system according to claim 5, wherein said manufacturing chamber includes an LSI manufacturing process. 7. The gas cleaning system according to claim 5, wherein said manufacturing chamber includes a photolithography manufacturing process in an LSI manufacturing process. 8. The method according to claim 5, wherein said manufacturing chamber includes a step of using a chemically amplified resist in an LSI manufacturing process.
A gas cleaning system according to claim 1. 9. The gas cleaning system according to claim 5, wherein said chemical contaminants are particles, mist and gas having a positive charge.