JPH08141343A - Filter box incorporating filters for gas removal - Google Patents

Abstract

PURPOSE: To make uniform a flow speed to each stage filter by providing different stage filters, each having a larger outlet or inlet opening area than that of a filter at an immediately located upper stage, by a baffle board, in a filter box incorporating gas removal filters. CONSTITUTION: If a suction pump is activated, air passes through a filter 4 from an inflow passage 3 and is discharged from an outflow passage 5. As the filter 4 is positioned at the center elevation of two downwardly tilting top guide plates 9, 9, the air flows from an inlet part 10 to an outlet part 11 as indicated by arrows A to C. In this case, the opening area of the outlet part 11 at each stage is larger than that at an immediately located upper stage by a baffle board. Consequently, the speed of the flow into each stage filter 4a to 4h is made uniform by increasing the flow at the lower stage and reducing that at the upper stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter box containing a plurality of gas removing filters.

[0002]

2. Description of the Related Art Conventionally, since the environment for manufacturing semiconductor products such as IC and LSI requires a dust-free environment, the manufacturing is performed in a clean room having a high performance (HEPA) filter in an air conditioning facility.

By the way, recently, as the degree of integration of semiconductor products has increased, it has been found that gaseous impurities in the environment in addition to fine particles adversely affect the quality and yield of semiconductor products.

When treating a large amount of air containing impurities in a clean room, a plurality of filters are built in as one of the methods for satisfying the contradictory requirements of reducing the occupied area of the filter and reducing the pressure loss of the air conditioning system. The box is used.

[0005]

In a conventional HEPA filter or the like for removing fine particles, even if the inflowing air to the filter surface is unevenly flown, due to the blocking resistance of the membrane surface due to the physically removed fine particles. The flow is transferred to the unoccluded surface, resulting in full use of the filter's capabilities.

[0006] However, in a filter for removing gas, gas is chemically adsorbed, and therefore, if there is a drift in the air flowing into the filter surface, that portion loses its effectiveness earlier. As a result, the apparent processing efficiency is reduced early and the entire capacity is not used, and the life ends. Therefore, when installing a filter for the purpose of removing gas, how to make the velocity of the air flowing into the filter surface uniform becomes a problem.

It is an object of the present invention to provide a filter case containing a plurality of gas removing filters for equalizing the flow velocity of air flowing into the filter surface.

[0008]

According to the present invention, a plurality of gas removing filters are housed in a stack in a box main body, and an air inlet is provided on the primary side of the upper part of the box main body.
An air outlet is provided on the secondary side, and a baffle plate that increases the aperture ratio toward the lower side is provided on the air inlet or air outlet side of the filter.

Further, according to the present invention, an upper guide plate is provided above the gas removing filter so that the air inlet is opened and inclined downward to the air outlet side and the air outlet side is closed, and the air inlet side is closed. A lower guide plate is provided which is inclined downward to the air outlet side and opens at the air outlet side.

Further, according to the present invention, the gas removing filter is composed of an assembly of ion-exchange fiber woven fabrics which are vertically pleated from the air inlet side to the air outlet side.

[0011]

In the filter box having a plurality of gas removal filters constructed as described above, the flow rate of the lower filter is increased by increasing the opening area of the outlet or the inlet by the baffle plate as the lower filter. As the number increases
It is possible to reduce the flow rate of the upper filter, and thus make the flow rate to the filters of each stage uniform.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4, the box body 1 of the filter box is formed in a vertically long rectangular parallelepiped, and the upper surface of the box body 1 has air inlets 2 on both sides in the longitudinal direction and a suction not shown. An air outlet 6 connected to the pump is provided in a protruding manner. And in the box body 1,
A vertical inflow passage 3 communicating with the air inflow port 2 and a vertical outflow passage 5 communicating with the air outflow port 6 are formed,
Between these two passages 3 and 5, a plurality (8 in the illustrated example)
Individual) gas removal filters 4a to 4h (hereinafter, referred to as reference numeral 4 when collectively referred to) are housed in a stack with a gap therebetween.

The gas-removing filter 4 is formed of an aggregate of ion-exchange fiber woven fabric a which is formed into a pleat shape from the inflow passage 3 side to the outflow passage 5 side.
However, it is not limited to this, and activated carbon, impregnated activated carbon, activated carbon fiber, zeolite, or the like can be used.

Referring also to FIG. 5, the gas removing filter 4 is placed on a shelf frame 7 having an opening 8. An upper guide plate 9 which also serves as a lower guide plate is provided above the filter 4.

Above the one filter 4, the upper guide plate 9 is open on the side of the inflow passage 3 to form the inlet portion 10, is inclined downward to the side of the outflow passage 5 and is closed on the side of the outflow passage 5. Further, below the filter 4, the inflow passage 3 side is closed, the outflow passage 5 side is inclined downward, and the outflow passage 5 side is opened to form an outlet portion 11. Therefore, the filter 4 is
The two parallel upper guide plates 9, which are inclined downward toward the outflow passage 5, are horizontally supported at a substantially central height. A baffle plate 12 is vertically provided at the upper edge of the outlet 11. For the baffle plate 12, punching metal, wire mesh, or the like can be used.

The opening ratio of the outlet portion 11 by the baffle plate 12 is formed so as to be gradually increased from the upper filter 4a to the lower filter 4b. That is,
In the first and second stage filters 4a and 4b, for example, 3
3.3%, in the 3rd to 5th filters 4c to 4e, for example, 50%, to the 6th and 7th filters 4f and 4g, for example, 66.7%, to the 8th filter 4h On the other hand, for example, 100% is adopted.

Next, the operation will be described.

When the suction pump is operated, air passes through the air inlet 2, the inflow passage 3 and the filter 4, and is discharged from the outflow passage 5 and the air outlet 6. At that time, as described above, the filter 4 is positioned at the height of the center of the two upper guide plates 9 and 9 which are inclined downward, so that the air flows from the inlet portion 10 to the outlet portion 11 as indicated by arrows A to C. Flow like.

At this time, when the baffle plate 12 is not provided, as shown in FIG. 7, the flow velocities of the filters 4a to 4h in each stage are different from each other. That is, the width of the flow velocity between the first stage filter 4a and the eighth stage filter 4h is large. This is because the flow rate of the inflow passage 3 causes the flow rate of the eighth-stage filter 4h to be smaller than that of the first-stage filter 4a.

On the other hand, by increasing the opening area of the outlet section 11 of each stage by the baffle plate 12 on the lower stage side, the flow rate on the lower stage side is increased and the upper stage side is decreased, as shown in FIG. It is possible to equalize the flow velocity entering the filters 4a to 4h.

[0022]

Since the present invention is constructed as described above, the flow velocity of the air entering the filter surface is made uniform,
The full power of the filter can be used to extend its life.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a side view of FIG.

FIG. 4 is a top view of FIG.

FIG. 5 is a front sectional view showing a main part.

FIG. 6 is a distribution diagram of the flow velocity of air flowing into each filter surface for explaining the effect of the present invention.

FIG. 7 is a drawing corresponding to FIG. 6 of a conventional filter box.

[Explanation of symbols]

 a ... Ion exchange fiber woven cloth 1 ... Box body 2 ... Air inlet 3 ... Inflow passage 4 ... Gas removal filter 5 ... Outflow passage 6 ... Air outlet 7 ... Shelf frame 8 ... Opening 9 ... Upper guide plate 10 ... Entrance 11 ... Exit 12 ... Baffle plate

Claims (3)

[Claims] 1. A plurality of gas-removing filters are stacked in a box body, an air inlet is provided on a primary side of an upper part of the box body, an air outlet is provided on a secondary side of the box body, and A filter box containing a plurality of gas removing filters, characterized in that a baffle plate having a larger opening ratio is provided on the side closer to the air inlet or the air outlet. 2. An upper guide plate is provided above the gas removing filter, the air inlet being opened and the air outlet being inclined downward and the air outlet being closed, and the air inlet being closed and the air outlet being closed. 2. A filter box having a plurality of gas removal filters according to claim 1, further comprising a lower guide plate which is inclined downwardly and whose air outlet side is opened. 3. The gas removing filter is composed of an assembly of ion-exchange fiber woven fabrics which are vertically formed into a pleat shape from the air inlet side to the air outlet side. A filter box with multiple built-in gas removal filters.