JP2003126625A - Parallel flow air filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin parallel flow air filter capable of having performances required at a filter setting place in a low cost. SOLUTION: In a filter medium of the parallel flow air filter, the passing direction of air and the direction of cellular through-holes are almost parallel. The medium is composed of a filter functioning part and a spacer part, or a non-filter function part.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a parallel flow type air filter.

[0002]

2. Description of the Related Art A conventional filter material for a parallel flow type air filter for removing a specific gaseous substance contained in air is a sheet-like material having a filter function for removing a specific gaseous substance by adsorption or decomposition. An aggregate of minute cell-like through-holes such as a honeycomb structure and a corrugated structure constituted by is known. Since such an air filter can achieve higher performance as more filter function filter medium is filled in a limited space, how to uniformly and densely fill the filter function filter medium. Has been examined.

[0003]

However, this is not so high for a circulation type clean room where air is circulated and passes through a filter many times to repeatedly perform processes such as adsorption and decomposition. It is possible to reach a sufficiently clean environment without having a filter function. Therefore, as described above, in the conventional technology for uniformly and densely filling the filter function filter medium, the filter function is too high and an over-spec filter is used.
Unnecessarily expensive filters were used, leading to higher costs.

On the other hand, there is a method of reducing the content ratio of the gas adsorbent such as the adsorbent or the decomposing agent contained in the filter function filter medium in order to reduce the cost by reducing the filter function.
However, in this method, since the adsorption performance and the like of the filter function filter medium is lowered, the adsorption zone becomes long when, for example, the gaseous substance is removed by adsorption, and the specific gaseous substance in the air to be treated is In order to remove it, it becomes necessary to increase the thickness of the filter to secure a long contact distance between the air to be treated and the filter medium. However, if the space where the filter is installed is limited, increasing the thickness may cause the filter not to be inserted. Further, even if the filter can be made thicker, the pressure loss of the filter becomes high.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of the above problems, the present inventors have reached the following invention. That is, it has been found that the above-mentioned problems can be solved by a parallel-flow type air filter characterized in that the filter medium is composed of a filter function filter medium and a spacer filter medium which is a non-filter function part.

Here, the parallel-flow type air filter is composed of a filter medium containing at least a part of a large number of cell-like through holes such as a honeycomb structure, a corrugated structure, or a lattice structure. The ventilation direction is substantially parallel to the penetration direction of the cell-shaped through hole. When a high-performance filter is not required by performing a process such as gas adsorption by circulating the air to be treated through the filter as described above many times, it is possible to simply reduce the amount of the filter function filter medium, If the amount is simply reduced, the packing density of the filter medium becomes too small and the air filter becomes scattered, and the filter medium collapses, making it difficult to maintain the structure of the filter. Therefore, the parallel flow type air filter is a filter function filter medium having a function of removing a specific gaseous substance contained in the air to be treated by adsorption or decomposition, and only by holding the form of the filter as a structure, By configuring with a spacer that does not have a filter function such as, by filling the filter function filter material in the filter in the required amount according to the performance required at the place where the filter is installed,
The other portions do not impair the filter performance, and if an inexpensive spacer filter medium is filled, the amount of the filter function filter medium can be reduced and the filter structure can be maintained.
By doing so, it is possible to optimize the design by changing the composition ratio of the filter function filter material and the spacer filter material according to the installation location, and it is possible to reduce the cost. Moreover, since the filled filter function filter medium has a high removal performance, it is possible to sufficiently remove the specific gaseous substance even if the contact distance between the air to be treated and the filter medium is short, and it is not necessary to thicken the filter. Absent.

Here, the filter function filter medium is a specific gaseous substance contained in the air to be treated, such as formaldehyde, toluene, ammonia, SOx, NOx, HCl,
It may contain a gas adsorbent for removing moisture or the like, a gas decomposing agent, or a combination thereof. Specifically, it is activated carbon, activated clay, zeolite, ion exchange resin, ion exchange fiber, dextrin, titanium oxide, diatomaceous earth, or silica gel. As a method of the filter function filter medium containing these gas adsorbents and gas decomposers,
There is a method of adhering, adhering, coating, impregnating and carrying the above gas adsorbent or gas decomposing agent (hereinafter referred to as a gas removing agent) on an inorganic material such as ceramics or glass, paper, or other base material. Further, pulp or synthetic fibers may be mixed with a gas removing agent for wet papermaking, and similarly, a gas removing agent may be mixed with pulp, synthetic fibers or the like to form a dry non-woven fabric.

[0008] The spacer filter medium may be any one as long as it has a through hole and has air permeability, but it is preferable that the spacer filter medium does not generate outgas which contaminates the air in the place where the filter is used such as a clean room.

For example, the above-mentioned filter function filter material excluding the gas removing agent, that is, one composed only of the base material portion of the inorganic material such as ceramics or glass, or the gas removing agent is mixed. It is also possible to use a paper or a dry non-woven fabric that is wet paper-made with only pulp or synthetic fibers.

Further, a material having a completely different material from the filter function filter material such as a structure having a through hole made of metal such as aluminum may be used.

Incidentally, the non-filter function section has an initial removal performance of a filter which has the same size and is composed of only the non-filter function section, is about 30% or less of the initial removal performance of a filter which is composed of only the filter function filter material. Is the part that is.

When these filter function filter material and spacer filter material are made of an inorganic material such as ceramics or glass and already have a structure of through cell holes, they can be applied as they are as an air filter unit.
In the case of a sheet material such as paper or non-woven fabric, a corrugated structure or a corrugated structure whose cross-sectional shape of the through hole is substantially triangular by bonding with an adhesive or the like that is hot-pressed or molded into a predetermined shape by pressing. A structure having through cell holes such as a hexagonal honeycomb structure or a substantially quadrangular lattice structure may be used. More preferably, when the heat-meltable fiber is mixed in advance when making a sheet-like material of wet papermaking or a non-woven fabric,
It is better to heat press bond. The reason why this method is preferable is that the use of the air filter according to the present invention is
It is often the place where very clean air is needed. When an adhesive is used, outgas such as an organic gas generated from the adhesive may have an unfavorable influence. Therefore, it is preferable to perform hot press bonding with a heat-meltable fiber that does not generate such an outgas. . In this case, the corrugated structure is most preferable because it has the best workability and the handleability of the finished filter medium is easy.

The filter function filter material and the spacer filter material thus obtained are mixed in a predetermined ratio in the opening surface of the air filter to obtain the desired parallel flow type air filter.

The filter function filter material and the spacer filter material are
Any arrangement may be used as long as they are mixed in a predetermined ratio within the opening surface of the air filter. Specifically, there is a method of alternately laminating a plurality of structures each having a cell-like through hole of a filter function filter material and a spacer filter material. For example, when the structure having the cellular through-holes has a corrugated structure or the like, the corrugated structures of the filter function filter material and the spacer part filter material are alternated, for example, one by one or at a predetermined number such as two and one. And so on.

When the bulk of the spacer filter medium is large and a bulky spacer filter medium is required, a spacer fabric such as a three-dimensional knitted fabric may be used. When the ratio of the spacer portion is large, in the case of the corrugated structure or the like described above, many layers of the spacer filter medium have to be laminated, but when a bulky material such as the spacer fabric is used, it is possible to obtain a predetermined number by laminating one layer. Since the space can be secured, the assembling work of the parallel flow type filter is simplified and the workability is good. When assembling using the filter medium having such a different structure, it is preferable that the difference between the pressure loss of the filter function filter medium and the pressure loss of the spacer filter medium is not too large. If the difference is large, uneven ventilation of the air to be treated occurs. That is, a portion with a large pressure loss has a small air flow rate, and a portion with a small pressure loss has a large air flow rate. Therefore, for example, when the pressure loss of the spacer filter medium is low and the pressure loss of the filter function filter medium portion is high, when only the spacer filter medium with low pressure loss is vented by the air to be treated and the target removal performance cannot be obtained. Because it will occur.

As a more preferable method of constructing the filter function filter material and the spacer filter material, there is a composite corrugated structure body in which the core of the corrugated structure is a spacer filter material and the liner is a filter function filter material. In this case, even if the filter function filter material and the spacer part filter material are not alternately laminated, a filter having the filter function filter material and the spacer filter material mixed therein can be formed in the filter only by stacking the composite corrugated structure, so that the parallel flow type Easy to assemble the filter.

Further, when the composite corrugated structure is used as it is, if the filter function filter medium is too much or the ratio of the filter material for the spacer portion is too large, a spacer filter medium different from the composite corrugate is used, or the composite corrugate and others are used. The parallel-flow type filter may be configured by using the filter function filter material of.

The parallel flow type air filter of the present invention can be used as an air filter unit by being housed in an air-impermeable outer frame.

It is known that gaseous substances in the air adversely affect the semiconductor manufacturing process, the liquid crystal display panel manufacturing process, and the hard disk manufacturing process, and the filter medium of the present invention is used in a clean room, a semiconductor manufacturing device, or a liquid crystal display plate manufacturing device. It can be preferably used as a filter material for a chemical filter by being incorporated in a semiconductor device manufacturing apparatus such as a hard disk manufacturing apparatus.

[0020]

FIG. 1 shows an example of an embodiment of a parallel flow type air filter of the present invention. This is a front view of the parallel-flow air filter 100 as viewed from the upstream side of the air to be treated. In this example, a corrugated structure having a cell-shaped through-hole whose cross-sectional shape is a substantially triangular shape is a corrugated structure 1 composed of a filter function filter medium containing a gas adsorbent and a spacer filter medium not containing a gas adsorbent. The corrugated structures 2 are alternately laminated. Although the air to be treated passes through the cell-shaped through holes, the filter function filter medium 1
The gaseous substance of the air to be treated which has been ventilated through the cell-shaped through-holes in contact with is adsorbed or decomposed. In this example, filter function filter medium 1 and spacer filter medium 2
Are alternately arranged one by one, but the configuration is not limited to this. The mixing ratio may be designed according to the performance required at the place where the filter is installed. If the mixing ratio of the filter function filter medium 1 and the spacer filter medium is 1: 1, the removal performance is not sufficient (if it is too high) The ratio of the filter function filter medium 1 can be increased (decreased) such that the ratio of the filter medium 1 and the spacer filter medium 2 is set to 2: 1 (1: 2). Further, it may be arranged randomly instead of being arranged regularly.

2 and 3 show examples of other embodiments of the present invention.

FIG. 2 shows a parallel flow type air filter 2 in which a spacer fabric 3 is used as a spacer filter medium and a filter function filter medium 1 and a spacer fabric 3 are laminated.
FIG. 10 is a front view of 00 as seen from the upstream side of the air to be treated.
Also in this embodiment, the filter function filter medium 1 is a corrugated structure in which the cross-sectional shape of the cell-shaped through holes is substantially triangular, and the filter medium contains a gas adsorbent. As the spacer fabric 3 of this example, a three-dimensional knit having a thickness about twice the height of the filter function filter material 1 is used. A corrugated structure in which the mixing ratio of the filter function filter media mixed in the filter space is constituted by the filter function filter media containing the gas adsorbent shown in FIG. 1 by merely alternately stacking one layer of the spacer fabric and one layer of the filter function filter media. The structure is equivalent to stacking the body 1 and the corrugate 2, which is a spacer containing no gas adsorbent, in a ratio of 1: 2.

In FIG. 3, the filter medium has a corrugated structure in which the cell-shaped through-holes have a substantially triangular cross-sectional shape. The corrugated molded body has a core 4 as a spacer filter medium and a liner 5 as a filter function filter medium. It is the front view which saw the parallel flow type air filter 300 which laminated the composite corrugated structure from the upstream side of the to-be-processed air ventilation. Such a structure is more preferable because it can disperse the filter function filter material more uniformly in the filter as compared with a structure in which other spacers and the filter function filter material are dispersed. If necessary, a composite corrugate may be combined with a corrugate containing the above-mentioned gas adsorbent, or a corrugate containing no gas adsorbent or a spacer fabric.

Instead of the air filter, a filter unit having an air filter housed in a non-permeable outer frame may be installed.

A schematic diagram of the clean room system is shown in FIG. In the present clean room system 400, the air passes through the air filter 7 from the outside air intake 6, the air filter 9 installed in the air carrying path 8, and the filter unit 11 installed in the air outlet 10. And is blown into the clean room 12. A semiconductor device manufacturing apparatus 13, such as a semiconductor manufacturing apparatus, a liquid crystal display panel manufacturing apparatus, or a hard disk manufacturing apparatus, is installed in the clean room 12, and an air filter 14 is also installed in this apparatus. In the present clean room system, the air taken in from the outside air is internally circulated in the flow path of the air transfer path 8, the outlet 10, and the clean room 12, and passes through the air filter a plurality of times, so that the target of high cleanliness is obtained. Processing air is put into a clean room or a semiconductor device manufacturing apparatus.

In this example, the air filters are installed at four locations, but any one location may be provided, or a plurality of locations may be combined.

The arrow 15 shown in the figure indicates the direction of the wind flowing through the clean room system 400.

[0028]

EXAMPLES First, a spacer filter media paper 16 composed of pulp and heat-meltable fibers having a core-sheath structure of polyethylene and polypropylene and having a melting point of 120 ° C. is 75% by weight and 25% by weight, respectively. Cation-exchange fiber, pulp, and a heat-meltable fiber having a core-sheath structure of polyethylene and polypropylene and a melting point of 120 ° C.
A paper 17 for filter function filter media composed of 0% by weight, 25% by weight and 25% by weight was prepared. Spacer filter media paper is hot-pressed with wave height of 3 mm and pitch of 3
mm corrugated, bonded to a flat paper for filter function filter media by hot press to obtain a composite corrugate, which was cut into a cell through hole direction of 40 mm and a width of 118 mm.

Similarly, the wave height is 3 mm and the pitch is 3 mm.
A corrugated spacer filter medium was obtained by hot-pressing and bonding the paper for spacer filter medium and the flat paper for spacer filter medium, which were formed into a corrugated shape, to a corrugated spacer and cut into a length of 40 mm in the direction of the cell through holes.

On the other hand, an aluminum plate is processed into a sheet metal, and the inside dimension is 121 mm in length × 121 mm in width × 40 in thickness in the ventilation direction.
mm and the opening of the ventilation part of the filter is 100 mm long
A filter outer frame 18 having a width of 100 mm was prepared.

The above composite corrugations and spacer filter media corrugates were alternately inserted into this outer frame one by one in a direction in which the cell through holes were parallel to the ventilation direction of the filter without any gap, and then the outer frame lid was attached. , Opening 100mm ×
A 100 mm parallel flow type air filter 600 was obtained. Figure 5
FIG. 3 is a front view of a part of a parallel-flow type air filter 500 in which a composite corrugate and a spacer filter medium corrugate are alternately laminated one by one, as viewed from the upstream side in the air passage direction of the treated air.
FIG. 6 shows a parallel flow type air filter 500 in an air-impermeable outer frame.
FIG. 4 is a perspective view of a parallel flow type air filter unit 600 in which is stored.

The ammonia removal efficiency of the filter thus obtained was measured. Ammonia removal efficiency was measured by installing a filter substantially vertically in a duct that flows in the horizontal direction. Specifically, the wind velocity from one side to the filter to be measured is 0.5 m / s, and the ammonia concentration volume ratio is 1 pp.
The air was blown so that the air adjusted to have a diameter of m could permeate the filter surface uniformly. As the concentration measuring method, a fixed amount of air was blown into the pure water from each of the upstream side and the downstream side of the filter to sample ammonia, and the aqueous ammonia solution was introduced into the ion chromatograph to quantitatively evaluate the ammonia concentration. Assuming that the gas concentration on the upstream side is P and the gas concentration on the downstream side is Q, the gas removal efficiency (%) of the filter is calculated by {(1-Q / P) × 100}. The gas removal efficiency (%) of this parallel flow type air filter is 50% even if the depth of the filter is as thin as 40 mm.
It was found to have the above gas removal performance.

[0033]

As described in detail above, according to the present invention,
Since the filter medium is composed of the filter function filter medium portion and the spacer filter medium portion, the thickness of the filter is thin,
In addition, it is possible to obtain a parallel flow type air filter that can design a filter having a performance required for a filter setting location and can reduce costs.

[Brief description of drawings]

FIG. 1 is a view of a parallel-flow type air filter of the present invention seen from a filter medium ventilation direction.

FIG. 2 is a view of the parallel-flow type air filter of the present invention viewed from the direction of the filter medium ventilation.

FIG. 3 is a view of the parallel-flow type air filter of the present invention seen from the direction of the filter medium ventilation.

FIG. 4 is a diagram showing an example of use of the air filter of the present invention.

FIG. 5 is a view of the parallel-flow air filter of the present invention seen from the direction of the filter medium ventilation.

FIG. 6 is a perspective view of an air filter unit using the parallel flow type air filter of the present invention.

[Explanation of symbols]

1: Filter Function Filter Material 2: Spacer Filter Material 3: Spacer Fabric 4: Core 5: Liner 6: Outside Air Intake Port 7: Air Filter of the Present Invention Installed in Outside Air Intake Port 8: Air Transport Route 9: In Air Transport Route The air filter 10 of the present invention installed: the air outlet 11: the air filter 12 of the present invention installed at the air outlet 12: clean room 13: device for manufacturing a device such as semiconductor 14: air filter 16 installed in a device for manufacturing a device such as semiconductor 16: Spacer Filter Media Paper 17: Filter Function Filter Media Paper 18: Non-Breathable Outer Frame

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F24F 7/06 F24F 7/06 C H01L 21/02 H01L 21/02 DF term (reference) 3L058 BF09 4D019 AA01 BA03 BA06 BA07 BA12 BA13 BB02 BB03 BB10 BC04 BC05 4D058 JA12 JB02 JB03 JB04 JB13 JB14 JB22 KB11 SA04 TA02 TA03 4G057 AA11

Claims (8)

[Claims] 1. A parallel-flow type air filter characterized in that the filter medium is composed of a filter function filter medium and a spacer filter medium. 2. The parallel flow type air filter according to claim 1, wherein the filter function filter medium contains at least one selected from a gas adsorbent and a gas decomposing agent. 3. The filter function filter medium according to claim 1, wherein the filter medium contains at least one selected from activated carbon, zeolite, activated clay, silica gel, ion exchange resin, dextrin, ion exchange fiber and titanium oxide. A parallel flow type air filter according to claim 1. 4. The parallel flow type air filter according to claim 1, wherein the filter medium includes a corrugated structure comprising a flat liner and a corrugated core. 5. The parallel flow type air filter according to claim 4, wherein the liner is the filter function filter medium and the core is the spacer filter medium. 6. The parallel flow type air filter according to claim 1, wherein the spacer filter medium includes a spacer fabric. 7. A clean room in which the parallel flow type air filter according to claim 1 is attached to a ventilation port. 8. An apparatus for manufacturing a semiconductor or the like having the parallel flow type air filter according to any one of claims 1 to 6 attached to a vent hole.