JPH05187704A - Duct for blowing air off - Google Patents

Abstract

PURPOSE:To make the amount of blown-out air uniform by a method wherein a porous plate extending in a longitudinal direction is provided, air flows through the interior as air is discharged through the porous plate, and a flow passage regulating body for gradually decreasing the section of a flow passage is arranged in a duct. CONSTITUTION:A clean room 1 is provided at an interior with a blast fan 2, a high performance filter 3, a cooler 6, a heater 7, and a moistening apparatus 8. Purified and air-conditioned air flowing through the filter 3 is blown off into a clean room 1 through a duct 5 for blowing air off extending to a ceiling 1a of the clean room 1. In this case, the duct 5 for blowing air off has other part than a part, making with the ceiling 1a, the other part being formed of a porous plate (a punching metal) 4. A flow passage regulating body 9, which is formed of a thin sheet such that the section of a flow passage is gradually decreased from the upper stream side 10 toward the downstream 11 of the duct 5, is arranged in the duct 5. This constitution causes uniformization of an air discharge amount along the direction of the length of the duct 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air blowing duct which has a perforated plate extending in the longitudinal direction and through which air flows while blowing air from the perforated plate.

[0002]

2. Description of the Related Art For example, a room for manufacturing semiconductors, electronic devices, precision instruments, a room for manufacturing chemicals and foods, an operating room of a hospital, or the like that requires clean air (hereinafter referred to as "clean room"). An air blowing duct is used to supply clean air to the room or to supply temperature- and humidity-controlled air to the room. When clean air with controlled temperature and humidity is blown out from the duct in a clean room,
The distribution of the amount of air blown out greatly affects the concentration distribution (cleanliness) of dust and the like in the space inside the clean room. If the distribution of the amount of air blown out from the duct is non-uniform, the dust particles present in the clean room and the dust particles generated by the manufacturing equipment in the clean room or the workers in the clean room, etc. Since it is difficult to remove it from the clean room due to the presence of a stagnant region of the air flow, it is difficult to improve the cleanliness in the clean room. On the other hand, when the distribution of the amount of air blown out from the duct is uniform, the dust particles in the clean room are quickly removed to the outside of the clean room due to the air flow distribution in the clean room. Remarkably improved. By making the distribution of the amount of air blown out from the ducts uniform in this way, it is possible to obtain a clean room with extremely small amounts of dust particles, bacteria, etc., which improves the manufacturing yield in the industrial field of semiconductors, etc. Treatment can be secured.

[0003]

By the way, in the air blowing duct, instead of supplying the air into the room only from the end portion of the duct, a perforated plate (for example, punching metal) is provided, and the air is blown over a wide area of the room. An air blowing duct for supplying air may be used (for example, JP-A-59-4).
(See Japanese Patent No. 4538).

In the air blowing duct having the perforated plate as described above, a baffle plate or the like is conventionally provided inside the air blowing duct in order to make the distribution of the air blowing amount uniform. It is not always sufficient to make the air-conditioning uniform, and there are areas with strong and weak blowouts partially, so there are areas with poor air cleanliness and areas where temperature and humidity adjustments do not work well. Existed.

In view of the above circumstances, it is an object of the present invention to provide an air blowing duct in which the air blowing amount is made uniform.

[0006]

The first air blowing duct of the present invention for achieving the above object has a perforated plate (for example, punching metal) extending in the longitudinal direction, and blows air from the perforated plate. While in the air blowing duct through which air flows, a flow path adjusting body that gradually reduces the flow passage cross-sectional area from the upstream side to the downstream side where the air flows is provided inside the air blowing duct. It is a feature.

The second air blowing duct of the present invention for achieving the above object has a perforated plate (for example, punching metal) extending in the longitudinal direction, and the air is blown from the perforated plate while the air is blown inside. In the flowing air blowing duct, the air blowing duct has a flow passage cross-sectional area that gradually decreases from the upstream side to the downstream side where the air flows.

Here, in the above-mentioned first or second air blowing duct, a flow path is provided at an inlet portion of the air blowing duct for adjusting a flow direction of the air when the air flows into the air blowing duct. It is preferable to provide an adjusting plate.

[0009]

Since the first air blowing duct of the present invention is provided with the flow path adjusting member, the flow velocity in the longitudinal direction in the duct can be made substantially the same at any position in the duct. The static pressure of the air is almost the same at any position in the duct, so that the blowout amount is made uniform.

The second air-blowing duct of the present invention is
In place of the flow path adjuster in the first air blowing duct, the air blowing duct itself has a flow passage cross-sectional area that gradually decreases from the upstream side to the downstream side of the air flow. Similar to the blowing duct, the longitudinal flow velocity in the duct can be almost the same at any position in the duct, and the static pressure of the air in the duct is almost the same at any position in the duct. The quantity is homogenized.

However, if there is a large imbalance in the air inflow velocity distribution at the inlet of the duct, the amount of blowout may not be made uniform due to that, but this may lead to a decrease in the flow passage adjusting body or the flow passage cross-sectional area. In addition, the provision of the flow path adjusting plate corrects this imbalance, and thereby makes the air blowing amount more uniform.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing the internal structure of an air cleaning duct arranged in a clean room, and FIG.
2A is a schematic sectional view taken along the line AA of FIG.
[Fig. 3] is a view schematically showing a part of punching metal which is an example of a perforated plate. Although the flow path adjusting plate 12 is provided in FIG. 1, a case where the flow path adjusting plate 12 is not provided will be described as a first embodiment, and a case where the flow path adjusting plate 12 is provided will be described as a second embodiment.

A case where the air blowing duct itself has a flow passage cross-sectional area that gradually decreases from the upstream side to the downstream side of the air flow will be described as a third embodiment. [Embodiment 1] A blower fan 2 and a high-performance filter 3 for removing dust in the air are provided inside the clean room 1, and the air purified by the filter 3 is applied to a ceiling 1a of the clean room 1. Perforated plate (punching metal) 4 except for the part that extends and contacts the ceiling 1a
The air is blown into the clean room 1 through a large number of small holes of the air blowing duct 5. In addition to not only cleaning the air but also adjusting the temperature and humidity here, equipment for this purpose is provided with a cooler 6 for cooling the air and a heater 7 for warming the air, and a humidifier for humidity adjustment. Bowl 8
Is also provided.

The size of the clean room 1 in this embodiment is 10 m (length) × 5 m (depth) × 2.7.
m (height), and the air cleaning device provided in this clean room 1 has a capacity of class 100 and a ventilation frequency of 100 times / hour. A HEPA filter is used as the high performance filter 3. The air blowing duct 5 in the present embodiment has a ship-shaped cross section as shown in FIG. 2, and extends along the ceiling of the clean room 1 in an elongated shape. As the air blowing duct 5, in addition to the duct having a bottom section in this embodiment, a duct having a rectangular section, or a duct having a bottom section or a rectangular section with rounded corners is generally used. Is used for.

The flow path adjusting body 9 is constructed by combining thin plates so that the cross-sectional area of the flow path gradually decreases from the upstream side 10 to the downstream side 11 of the duct 5, and in this embodiment, the flow path adjusting body 9 is formed. As shown in FIG. 2, the adjuster 9 is configured such that the distance d between the flow path adjuster 9 and the porous plate 4 is uniform in any direction and gradually decreases from the upstream 10 to the downstream 11. ing.

The total pressure of the air in the duct 5 (the dynamic pressure upsilon ^2/2
(Υ represents the flow velocity) + static pressure) is almost constant at any position in the duct 5, and the amount of air blowout mainly depends on the static pressure in the duct, so that the air blowout amount distribution is made uniform. Therefore, the flow velocity υ should be kept constant. Here, considering the case where the flow path adjusting body 9 is not provided, the flow rate becomes large and the static pressure decreases in the upstream 10 because the amount of air flowing in the duct 5 is larger than that in the downstream 11, and on the other hand, in the duct 5 downstream. On the contrary, since the amount of air flowing through is small, the static pressure becomes large. Therefore, when the flow path adjusting body 9 is not provided, the amount of air blown out becomes larger in the downstream side than in the upstream side 10. On the other hand, here, since the flow passage adjusting body 9 is provided so that the flow passage cross-sectional area gradually decreases from the upstream 10 to the downstream 11, the flow velocity υ is made uniform between the upstream 10 and the downstream 11, and The static pressure is also made uniform, so that the amount of air blown out is made uniform.

Further, in this embodiment, when viewed in the cross section shown in FIG. 2, the distance d between the flow path adjusting body 9 and the porous plate 4 is formed so as to be uniform in any direction. As for the same, the same amount of air is blown out, and the air blown out from the duct 5 is combined with the fact that the flow passage cross-sectional area is gradually reduced from the upstream side 10 to the downstream side 11. It will be evenly distributed throughout.

FIG. 4 is a diagram showing the air blowing velocity distribution (normalized) with respect to the distance from the duct inlet (upstream) with and without the flow path adjuster 9 provided in the duct 5. is there. Graph A is a graph showing a case where the flow path adjuster 9 is not provided, and graph B is a graph showing a case where the flow path adjuster 9 is provided. As shown in this figure, the flow path adjuster 9 greatly contributes to making the amount of air blowout uniform.

In the clean room 1 shown in FIG. 1, as a result of measuring the time until the cleanliness of class 100 is reached after the start of blowing clean air, the flow path adjusting body is about 30 minutes when the flow path adjusting body 9 is not provided. When 9 was provided, it took about 10 minutes. By uniformly distributing the clean air in the room in this manner, the air in the room is cleaned very quickly.

In the first embodiment, as shown in FIG. 1, the flow path adjusting body 9 is constructed so as to gradually reduce the flow path cross-sectional area over the entire region from the upstream 10 to the downstream 11. However, it is not always necessary to gradually reduce the flow passage cross-section over the entire region, and for example, the reduction of the flow passage cross-sectional area may be started from a point slightly lower than the inlet (upstream) of the duct 5. The flow path cross-sectional area may be reduced or the flow path cross-sectional area may be made constant for a partial region on the most downstream side of the duct 5. The degree of homogenization of the air blowing amount,
It is determined in consideration of ease of making the flow path adjuster 9 and the like.

[Embodiment 2] Next, the flow path adjusting plate 1 shown in FIG.
The case of having 2 will be described. FIG. 3 is a front view (A), a side view (B), a plan view (C), and an enlarged side view (D) showing an outline of the flow path adjusting plate 12 shown in FIG. 1. Duct 5 installed in the clean room 1 of Example 1
An internal flow path adjusting plate 12 is provided at an air inlet portion of the duct 5, and the flow path adjusting plate 12 has a movable airfoil section so that the direction of air flow can be adjusted in both vertical and horizontal directions. It is composed of a vertical blade plate 12a and a horizontal blade plate 12b.

These vane plates 12a and 12b are supported by the frictional force between them and the shafts, and will not move due to the flow of air, but they can be easily moved by hand. When it is found that the blowout from the duct 5 is a biased flow based on the measurement result of the blowout velocity, the wind direction can be adjusted by adjusting the directions of the blade plates 12a and 12b, thereby eliminating the bias. ..

The amount of air flowing out of the filter 3 and entering the duct 5 is uneven, so that in the case where there is a large imbalance in the inflow velocity distribution at the inlet of the duct 5, the flow path adjusting plate 12 Considering the case without
Due to this imbalance, the distribution of the blowing amount in the first portion of the upstream portion 10 of the duct 5 is not uniform (see the graph B in FIG. 4). On the other hand, in the case where the flow path adjusting plate 12 is provided, the uneven flow from the filter 3 is generated by the two types of blade plates 12a,
The flow in the horizontal and vertical directions is regulated by 12b, and the flow can be changed to a uniform flow in a certain direction. For this reason, the blowout amount in the upstream 10 is made uniform.

Graph C in FIG. 4 is a graph showing a case where both the flow path adjusting body 9 and the flow path adjusting plate 12 are provided. As shown in this graph C, the flow path adjusting body 9 and the flow path adjusting plate 1
The combined use of 2 has a more excellent effect on the uniformization of the air blowing amount, whereby the air blown from the duct 5 spreads more evenly over the entire interior of the clean room 1, and the air in the room is This will have a great effect on cleaning.

[Embodiment 3] FIG. 5 is a schematic view showing an internal structure of an air cleaning duct according to Embodiment 3 arranged in a clean room, and FIG. FIG. 6B is a schematic cross-sectional view taken along the line, schematically showing part of punching metal which is an example of a perforated plate. 5 and 6, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and the duplicated description will be omitted.

The air blowing duct 5 has a width (see FIG. 6).
(Horizontal direction in (a)) is kept constant, and in the vertical direction from the upstream 10 to the downstream 11, the perforated plate 4 and the ceiling 1a.
Is gradually narrowed, so that the flow passage cross-sectional area is reduced at a constant rate. Further, since the flow velocity of the air in the air blowing duct 5 is about 10 m / s or less, the air flow and the wall frictional resistance of the ceiling 1a are small, so that the air flow is not disturbed. Therefore, the air blown out from the air blowing duct 5 is evenly distributed over the entire interior of the clean room 1. When the air blowing duct 5 of this embodiment is provided, the same good results as those of the graphs B and C of FIG. 4 are obtained depending on whether or not the flow path adjusting plate 12 (see FIGS. 1 and 3) described above is provided. A uniform airflow distribution was obtained.

In the third embodiment, as shown in FIG. 6 (a), the air blowing duct 5 has its flow passage cross-sectional area gradually reduced in the vertical direction while keeping the width in the horizontal direction constant. However, the dimension may be gradually narrowed in the width direction (lateral direction) of the air blowing duct. Further, the reduction rate of the flow passage cross-sectional area does not have to be constant, and the flow passage cross-sectional area may be reduced exponentially or parabolically. Further, it is not always necessary to reduce the flow passage cross-sectional area over the entire region, and depending on the length of the air blowing duct, there is a portion where the flow passage cross-sectional area of the air blowing duct is kept constant. May be.

The results of the cleanliness recovery characteristic test in the clean room in Examples 2 and 3 are shown in FIG. 7D. Before the recovery characteristic test, the dust concentration of 0.5 μm or more was about 400,000 / cf (cubic feet) in the clean room. Particle concentration is 10
Dramatically reduced to 0 / cf or less, achieving class 100 cleanliness, and 10 // 14 minutes after the start of recovery characteristic test.
It was possible to realize a clean space with a high cf. See also FIG.
E is 0.5 in the case of the blowout amount distribution shown in A of FIG.
A dust particle concentration of μm or more is obtained, and when E in FIG. 7 is compared with D in FIG. 7 according to the present invention, a remarkable improvement in cleanliness according to the present invention is apparent.

[0029]

As described above, the first air blowing duct of the present invention includes the flow passage adjusting body that gradually reduces the flow passage cross-sectional area from the upstream side to the downstream side where the air flows. The distribution of the amount of air blown out from the perforated plate is made uniform at any position from the upstream side to the downstream side.

Further, the second air blowing duct of the present invention has the flow passage cross-sectional area in which the air blowing duct itself gradually decreases, and therefore, like the first air blowing duct of the present invention, the upstream side is the same. The distribution of the amount of air blown out from the perforated plate is made uniform at any position from the side to the downstream side. In addition to the above-mentioned flow path adjusting body or the reduction of the flow path cross-sectional area, if a flow path adjusting plate for adjusting the flow direction in both the horizontal and vertical directions is provided at the air inlet part of the air blowing duct, the duct upstream The air blowout amount distribution is further homogenized at any position from the side to the downstream side.

Since the air cleanliness in the clean room is remarkably enhanced by appropriately equalizing the distribution of the air blowing amount as described above, the pathogens such as dust particles and bacteria in the clean room are significantly reduced. There are remarkable effects such as improvement of production yield and product quality in the industrial field of semiconductors and the like, and improvement of product quality in the food and drug manufacturing fields.

[Brief description of drawings]

FIG. 1 is a schematic view showing an internal structure of an air cleaning duct arranged in a clean room.

FIG. 2 is a schematic cross-sectional view (a) taken along the line AA of FIG. 1 and a view (b) schematically showing a punching metal which is an example of a perforated plate.

FIG. 3 is a schematic view of the flow path adjusting plate shown in FIG.

FIG. 4 is a diagram showing an air blowing speed with respect to a distance from a duct inlet.

FIG. 5 is a schematic diagram showing Embodiment 3 of the internal structure of a duct for air cleaning arranged in a clean room.

6 is a schematic cross-sectional view (a) taken along the line BB of FIG. 5 and a view (b) schematically showing a punching metal which is an example of a perforated plate.

FIG. 7 is a diagram showing cleanliness recovery characteristics in a clean room of Examples 2 and 3.

[Explanation of symbols]

 1 Clean room 2 Blower fan 3 Filter 4 Perforated plate 5 Duct 9 Flow path adjusting body 12 Flow path adjusting plate (blade-shaped)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Akira Sueda Akira Sueda 2-3 2-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Kawasaki Steel Co., Ltd. Tokyo headquarters (72) Masao Kimura 2-3 2 Uchisaiwaicho, Chiyoda-ku, Tokyo No. Kawasaki Steel Co., Ltd. Tokyo head office (72) Inventor Misao Osawa 4-20-4 Chuorinkan, Yamato City, Kanagawa Prefecture Hirayama Equipment Co., Ltd.

Claims (3)

[Claims] 1. An air blowout duct having a perforated plate extending in the longitudinal direction, through which air flows while blowing air from the perforated plate, inside the air blowout duct, from the upstream side to the downstream side where the air flows. An air blowing duct comprising a flow path adjusting body that gradually reduces the flow path cross-sectional area toward the side. 2. An air blowing duct having a perforated plate extending in the longitudinal direction, in which air flows while blowing air from the perforated plate, the air blowing duct extending from an upstream side to a downstream side of the air flow. An air-blowing duct having a flow passage cross-sectional area that gradually decreases toward the air-blowing duct. 3. A flow path adjusting plate for adjusting a flow direction of air when air flows into the air blowing duct is provided at an inlet portion of the air blowing duct.
Alternatively, the air blowing duct described in 2.