JPH11207117A - Gas purification filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove both organic and inorganic gaseous pollutants and to reduce the pressure drop of a gas passing through the filter and the installation space of the filter by using an adsorbent having ion exchange groups introduced through graft polymerization, as the constituent material of a filter medium. SOLUTION: In this filter, a filter medium 2 that is formed from a two-ply nonwoven fabric made of fibrous active carbon into which cation exchange groups are introduced by graft polymerization, so as to have a pleated shape, is placed inside a rectangular frame 1 and also, a corrugated separator 4 made of aluminum is inserted between every adjacent two of folded sides of the filter medium 2. In the filter medium 2 having a pleated shape, a gas passage is secured between every adjacent two of the folded sides of the filter medium 2 by the corrugated separator 4, to increase the filtration area of the filter medium 2 and to reduce the pressure drop of a gas passing through the filter, while reducing size of the filter as a whole. At this time, organic gaseous pollutants in the gas passing through the filter are removed by adsorption with the fibrous active carbon and concurrently, inorganic gaseous pollutants in the gas are removed by ion exchange with the cation exchange groups introduced into the fibrous active carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas purification filter used for purifying a room atmosphere in a clean room.

[0002]

2. Description of the Related Art Conventionally, to remove organic gaseous pollutants contained in a gas, an adsorbent filter using an adsorbent such as activated carbon as a constituent material of a filter medium is known. In order to remove inorganic gaseous pollutants (acidic substances, basic substances, and various ions) contained in water, there is known an ion exchange filter using ion exchange fibers as a constituent material of a filter medium. As a filter for removing both organic gaseous pollutants and inorganic gaseous pollutants by using both the exchange and the exchange, an activated carbon fiber layer and an ion exchange fiber layer are laminated to form a filter medium. There is a laminated type in which the filter medium is formed, or a mixed type in which a filter medium is formed with a mixed fiber of activated carbon fiber and ion exchange fiber (for example, JP-A-6-142439, JP-A-3-607).
No. 11).

[0003]

However, in either of the above-mentioned laminating type and mixing type, the adsorbent (activated carbon fiber in the above example) and the ion-exchange group carrier (ion exchange fiber in the above example) are used. Since the filter medium is formed by using various kinds of constituent materials, the thickness of the filter medium is greatly increased in order to obtain satisfactory removal efficiency for both the organic gaseous pollutants and the inorganic gaseous pollutants. For this reason, there is a problem that the pressure loss of the passing gas increases and the power required for gas ventilation increases, and the space required for installing the filter increases.

[0004] In view of this situation, the main problems of the present invention are:
By the rational improvement of the filter material components, while efficiently removing both organic gaseous pollutants and inorganic gaseous pollutants, the pressure loss of passing gas can be greatly reduced,
An object of the present invention is to provide a gas purification filter that can greatly reduce the space required for installing the filter.

[0005]

Means for Solving the Problems [1] According to the first aspect of the invention, the adsorbent in which an ion exchange group is introduced by graft polymerization is used as a constituent material of a filter medium. Since it is used as a carrier, the amount of these adsorbents and ion exchange groups is sufficient to obtain high removal efficiency for both organic gaseous pollutants and inorganic gaseous pollutants. The thickness of the filter material is reduced by the amount of the ion exchange group carrier as compared to the case where the filter material is formed by laminating or mixing two types of constituent materials of the adsorbent and the ion exchange group carrier, such as the lamination type and the mixing type. As a result, the pressure loss of the passing gas can be greatly reduced, and the space required for installing the filter can be greatly reduced.

In addition, since the steps of laminating and mixing two kinds of constituent materials, ie, an adsorbent and a carrier having an ion exchange group, are not required for forming the filter medium, the filter medium can be easily formed and the cost of the filter medium can be reduced. Can be.

If the ion exchange group is introduced into the adsorbent by the graft polymerization, if the graft polymerization by radiation is adopted, the introduction can be performed efficiently and easily, which is advantageous in terms of the formation of the filter medium. The method of graft polymerization is not limited to this, and may be graft polymerization using light, heat, a chemical, or the like.

As the adsorbent, one or more of various materials can be selected and employed as long as they have an adsorbing property to organic gaseous pollutants. Adsorbents of various shapes can be employed.

Further, in forming a filter medium using an adsorbent as a constituent material, the adsorbent may be of a type used for forming a filter medium while being supported on a suitable carrier, or a type used for forming a filter medium without being supported on a carrier. Either may be adopted.

[2] In the second aspect of the present invention, since the non-woven fabric, the woven fabric or the aggregate formed body of the fibrous adsorbent into which the ion-exchange group is introduced is used as the filter medium, the thickness of the filter medium can be reduced as described above. Except for the step of introducing ion-exchange groups by graft polymerization, a non-woven fabric, a woven fabric, or a filter similar to a general filter using an aggregate formed body of fibers as a filter medium, and easily filtered using a similar manufacturing apparatus. Can be manufactured, and the manufacturing cost of the filter can be reduced.

The introduction of ion-exchange groups by graft polymerization is carried out after forming a nonwoven fabric, woven fabric or aggregated molded product with a fibrous adsorbent, or before introducing a nonwoven fabric, woven fabric or aggregated molded product. Any of the methods performed for the fibrous adsorbent may be employed.

When fabricating a filter using a nonwoven fabric, a woven fabric, or an aggregated molded product of a fibrous adsorbent as a filter material, by making the nonwoven fabric, woven fabric, or the aggregated molded product into a honeycomb shape or a pleated shape, the filter configuration can be reduced in size. While it is possible to secure a large filtration area and reduce the pressure loss of the passing gas more effectively, the shape and equipment form of these nonwoven fabrics, woven fabrics or collectively formed bodies as filter media are not limited thereto. For example, various shapes and forms can be adopted, such as a bag-like shape or a plurality of parallel or series combinations.

[3] In the invention of claim 3, since both a cation exchange group and an anion exchange group are introduced into the adsorbent as the ion exchange group, the cation exchange group is used to remove the inorganic gaseous pollutants. Basic substances and cations can be removed, and acidic substances and anions can be removed by an anion exchange group, so that inorganic gaseous pollutants can be removed regardless of polarity. It is a suitable filter when it is required to remove inorganic gaseous pollutants irrespective of their polarity together with the removal of systemic gaseous pollutants.

[4] In the invention of claim 4, only one of a cation exchange group and an anion exchange group is introduced as an ion exchange group into the adsorbent. In other words, when only removal of basic substances and cations is required as an inorganic gaseous pollutant, the filter material is constructed by introducing only cation exchange groups into the adsorbent, and the basic substance to be removed by the cation exchange groups is used. When only the removal of acidic substances and anions is required as inorganic gaseous pollutants, only the anion exchange groups are introduced into the adsorbent, and the removal is performed by the anion exchange groups. Removes acidic substances and anions of interest.

That is, according to the type of the inorganic gaseous pollutant required to be removed as described above, a filter medium is adopted in which only one of the cation exchange group and the anion exchange group is introduced into the adsorbent. Thus, the formation of the filter medium can be facilitated and the cost of the filter medium can be reduced as compared with the case where both the cation exchange group and the anion exchange group are introduced into the adsorbent.

In the practice of the invention described in each claim, one or more kinds of cation exchange groups can be selected from various ones such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group. As the anion exchange group, one or more kinds of various groups such as a primary to tertiary amino group, a quaternary ammonium group, and a sulfonium group can be selected and employed.

[5] In the invention of claim 5, as the adsorbent, one selected from activated carbon, zeolite, activated alumina, silica gel, and a synthetic resin having adsorptivity is adopted.

That is, since these adsorbents have different adsorption performances depending on the type of the organic gaseous pollutant and also on the use conditions such as the temperature and humidity of the passing gas,
Select and use the optimal adsorbent from among these adsorbents as the adsorbent to be used as a filter medium component for ion-exchange group introduction, according to the type of organic gaseous pollutant required to be removed and the conditions of use. Thereby, the removal efficiency of the organic gaseous pollutants required to be removed can be further improved.

In selecting the adsorbent as a filter medium constituent material from the above options, only one type may be selected, or a plurality of types may be selected and used in combination. Is also good.

When a plurality of types of adsorbents are used in combination, the selected types of adsorbents are mixed into a filter material constituting material, or the selected types of adsorbents are laminated in a layer state for each type. Any of the forms used as the filter medium constituent material may be adopted, and the introduction of the ion-exchange group may be performed by introducing the same type of ion-exchange group into a plurality of selected adsorbents, or a plurality of selected forms. Any of the forms in which different types of ion exchange groups are introduced into the kind of adsorbent may be adopted.

[0021]

1 and 2 show a gas purifying filter, wherein 1 is a rectangular frame made of aluminum and 2 is a filter medium provided in the rectangular frame 1 in the form of a pleated two-sheet filter.
Is sealed with the sealant 3 over the entire periphery of the rectangular frame 1.

Reference numeral 4 denotes a corrugated separator made of aluminum foil interposed between the folded sides of the filter medium 2. In the above-mentioned pleated shape, the corrugated separator 4 separates the folded sides of the filter medium 2 from each other. By securing the ventilation path, the area of the filter medium 2 (filtration area) is increased and the pressure loss of the passing gas A is reduced while reducing the size of the entire filter.

The filter medium 2 is formed of a fibrous activated carbon nonwoven fabric, and a cation exchange group is introduced into the fibrous activated carbon as a filter medium constituent material by graft polymerization.

That is, the organic gaseous pollutants contained in the passing gas A are removed by adsorption with the fibrous activated carbon, and at the same time, the inorganic gaseous pollutants (ammonia in this example) contained in the passing gas. Is removed by ion exchange with a cation exchange group.

In order to remove both the organic gaseous pollutants and the inorganic gaseous pollutants, an ion exchange group is introduced by graft polymerization into the fibrous activated carbon itself as a filter material constituent material. By mixing the ion-exchange fiber and the activated carbon fiber, a filter medium is formed, or the thickness of the filter medium 2 is reduced by half in comparison with the case where the filter medium is formed by laminating the filter medium in different fiber layers. The pressure loss of A is halved, and the same filter removal efficiency is obtained for each of the organic gaseous pollutants and the inorganic gaseous pollutants while making the filter configuration thinner.

FIG. 3 is a view showing the construction of a clean room showing an example of the installation of the filter F. Reference numeral 5 denotes a purifying target room, 6 denotes a fan filter unit arranged side by side on a ceiling of the target room 5, and 7 denotes each fan filter unit 6. , 8 is a grid floor of the target room 5, 9 is a return air chamber for receiving room air discharged through the grid floor 8, and 10 is a return connecting the return air chamber 9 and the air supply chamber 7. The airway,
By operating the fan 6a provided in each fan filter unit 6, air is circulated in the order of the air supply chamber 7, the purification target chamber 5, the return air chamber 9, and the return air passage 10.

Each fan filter unit 6 is a high-performance filter using fibrous activated carbon having a cation exchange group introduced therein as a filter material constituting the first filter, and glass fiber as a filter material constituting the filter material. 6b (HE
A PA filter or an ULPA filter) is provided as a second filter, and the first and second filters F and 6b are arranged in series in that order from the upstream side in the air passage direction.

That is, in the above-mentioned air circulation, organic gaseous pollutants and inorganic gaseous pollutants contained in the circulating air A are removed by the first filter F of each fan filter unit 6. Filter unit 6
The fine particles contained in the circulating air A are removed by the second filter 6b, and the clean air is supplied to the clean target room 5, thereby maintaining the clean target room 5 at a required cleanliness.

Reference numeral 11 denotes a manufacturing apparatus disposed in the chamber 5 to be purified. When the exhaust gas from the manufacturing apparatus 11 contains ammonia and organic gaseous pollutants,
As shown in the figure, the filter F is provided at an exhaust port 11a of the manufacturing apparatus 11 to remove ammonia and organic gaseous pollutants contained in exhaust gas.

In this embodiment, the filter F
Is shown in each fan filter unit 6, but as shown in the figure, the filter F is provided in parallel with the fan filter unit 6 or in place of the fan filter unit 6. Return air chamber 9
And the filter F may be used to remove organic gaseous pollutants and inorganic gaseous pollutants in the circulating air A.

12 is an exhaust air path for discharging a part of the circulating air A out of the system, 13 is an external air introducing air path for introducing outside air into the circulating air A, and 14 is an external air conditioner for adjusting the introduced external air. The external conditioner 14 also includes a pre-filter 14a, a temperature control coil 14
b, a humidifier 14c, and an air supply fan 14d, and the filter F is provided. The filter F removes organic gaseous pollutants and inorganic gaseous pollutants contained in the outside air.

[Another Embodiment] Next, another embodiment will be described.

In the above-described embodiment, an example in which a cation exchange group is introduced into fibrous activated carbon as a filter material constituting material has been described. However, the adsorbent as a filter material constituting material is not limited to activated carbon, but may be zeolite, activated alumina, or silica gel. Various materials can be employed as long as they have an adsorptivity to organic gaseous pollutants, such as a synthetic resin having an adsorptivity or other porous substances.

Further, instead of introducing only a cation exchange group into the adsorbent as a filter material constituent, an embodiment in which only an anion exchange group is introduced according to the type of the inorganic gaseous pollutant to be removed, or A form in which both an exchange group and an anion exchange group are introduced may be adopted.

In the above-described embodiment, an example is shown in which the gas purifying filter according to the present invention is incorporated in a fan filter unit together with a high-performance filter such as a HEPA filter or an ULPA filter by taking advantage of the advantage that the thickness of the filter medium can be reduced. However, the gas purification filter according to the present invention is not limited to a built-in device for a fan filter unit used in a clean room, and is not limited to a built-in device for an external controller or a built-in device for a manufacturing apparatus as in the above-described embodiment. It can be used in various equipment forms in the field.

In addition, a filter using an adsorbent having an ion-exchange group introduced therein as a filter material and a filter using glass fiber as a filter material are separately manufactured. In carrying out the above, the adsorbent into which the ion-exchange group is introduced and the glass fiber may be laminated in different layers to form a filter medium of one filter.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall configuration of a filter.

FIG. 2 is an enlarged perspective view showing a filter structure with a part cut away.

FIG. 3 is a configuration diagram of a clean room.

[Explanation of symbols]

 2 Filter media

Claims (5)

[Claims] 1. A gas purification filter comprising an adsorbent into which an ion exchange group has been introduced by graft polymerization as a constituent material of a filter medium. 2. The gas purifying filter according to claim 1, wherein a nonwoven fabric, a woven fabric, or a molded body of the fibrous adsorbent into which the ion exchange group is introduced is used as a filter material. 3. The gas purification filter according to claim 1, wherein both a cation exchange group and an anion exchange group are introduced into the adsorbent as the ion exchange group. 4. The gas purification filter according to claim 1, wherein only one of a cation exchange group and an anion exchange group is introduced into the adsorbent as the ion exchange group. 5. The gas purification filter according to claim 1, wherein the adsorbent is selected from activated carbon, zeolite, activated alumina, silica gel, and a synthetic resin having adsorptivity.