JP2007178065A - Air returning device for clean room - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air returning device for a clean room capable of exerting stable air cleaning effect without unevenness in indoor cleanliness. <P>SOLUTION: This air returning device for the clean room comprises a perforated panel 18 configurating an upper floor surface 20 and comprising ventilatable through holes 18a, and a plurality of air returning ducts 24 disposed between the upper floor surface 20 and a floor slab surface 14. A plurality of suction openings 26 are respectively formed on an end portion of each of air returning ducts 24 in a state of being expanded to a prescribed range of the upper floor surface 20. The suction openings 26 are vertically opened at the end portions of the air returning ducts 24. The air returning ducts 24 are formed into the L-shape, the plurality of air returning ducts 24 are arranged in parallel with each other in a prescribed range between the upper floor surface 20 and the floor slag surface 14, and the suction openings 26 are dispersed to the prescribed range. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a clean room return air device for purifying and circulating air in a clean room.

  Conventionally, in a semiconductor manufacturing factory, a pharmaceutical factory, a precision machine manufacturing factory, and the like, a manufacturing process is placed in a clean room in order to prevent adverse effects of dust on manufacturing equipment and products. This clean room is provided with an air supply device and a return air device for circulating and purifying indoor air in order to keep indoor air clean. Ventilation by an air supply device and a return air device is generally performed by a downflow method, and air purified from a filter provided at a blowout portion of a ceiling is blown into a room, and air is emitted from a plurality of gratings provided on a floor surface. This is a part of the air supply system that guides the air accompanied by dust generated in the clean room using the underfloor chamber formed between the floor slab surface and the upper floor lower surface in the lower floor surface as a common air passage. The air is sucked from the suction part of the air conditioner, and air is sent again to the blowing part of the ceiling to circulate.

Conventionally, for example, as shown in FIGS. 5 and 6, the floor of the clean room 52 provided with the air supply device 63 and the return air device 50 is generally formed as a free access floor 54 in which the arrangement of the floor panels can be changed. . The floor panel forming the free access floor 54 is formed of, for example, cast material, and is supported by a support 58 fixed to a floor slab surface 56 of concrete or the like. In order to cope with the recent increase in the weight of installed equipment, this floor panel is attached by appropriately combining a holeless panel 60 with a smooth surface and a perforated panel 61 provided with a plurality of through-holes to allow ventilation. It has been. And the return air apparatus 50 sucks room air under the floor of the free access floor 54 through the perforated panel 61, and from the suction port 62 provided in the side wall portion under the floor by the blower 66 that is a part of the air conditioner 65. The air is sucked into the suction port 67 of the air conditioner 65 of the air supply device 63. The air blown out to the duct 64 by the blower 66 is blown to the blowout portion 68 of the ceiling incorporating the filter, and the air blown down the clean room is circulated by being sucked into the return air device 50 again.
JP-A-6-137624 Japanese Patent Laid-Open No. 6-159751 JP-A-8-152170 JP-A-11-63602 JP 2002-303438 A

  In the above-described conventional technology, as shown in FIGS. 5 and 6, air is blown out into the room from a blow-out portion 68 provided on the ceiling of the clean room 52 and including a filter (not shown), and a hole is provided in the free access floor 54. Air is sucked under the floor from the panel 61, and the air is circulated again to the ceiling via the duct 64. At this time, as shown in FIG. 7, air in the range of the curve A of the free access floor 54 is sucked into the suction port 62.

  Here, for example, when the perforated panel 61 is blocked by the transferred equipment due to a change in the layout of the manufacturing process, the air flow in the room changes, and air circulation such as stagnation of the room or bias in suction There was a problem that caused a failure. Therefore, layout changes and the like have been dealt with by rearranging the position of the perforated panel 61 where there is no device.

  In the case of the above-described conventional technology, as shown in FIG. 7, there is a large amount of airflow near the position of the suction port 62 provided in the side wall portion under the floor, and the distant portion has less ventilation, and the distant panel 61 without holes. Some parts were hardly ventilated. Further, when the layout is changed, the air flow in the clean room 52 changes depending on the position of the device, and an air staying part may occur. If there is a difference in the downward air flow velocity distribution in the clean room 52, there is a difference in the cleanliness in the cleanroom, and there is a problem that the yield in manufacturing is affected by the low cleanliness part.

  Therefore, as shown in FIG. 5, there is a structure in which a shutter 70 is mounted on the lower side of the perforated panel 61 to adjust the amount of air to be sucked so that the distribution of the airflow velocity in the room is uniform. . However, in this structure, it is necessary to finely adjust the opening degree of the shutters 70 of all the plurality of perforated panels 61 while measuring the air flow, and most of the shutters 70 of the perforated panel 61 in the room. Since all the adjustments were made, the work was cumbersome and time-consuming, and the work efficiency was not good. In addition, when the layout of the clean room 52 is changed, the position where the perforated panel 61 is blocked changes. Therefore, it is necessary to adjust the opening of the shutter 70 each time the perforated panel 61 is rearranged.

  Further, instead of the shutter 70, as disclosed in Patent Document 1, it is also known to use a panel with a fan. In this case, wiring and a power source for supplying power to the motor for driving the fan are required, and a control device for controlling the rotation speed of the fan is also required, which is costly. Furthermore, when changing the layout, the position of the perforated panel with fan is changed, so the power and control wiring change work occurs, and the weight is heavy and the work efficiency is not good. Is unsuitable.

  In addition, in Patent Document 2, the air around the equipment installed on the free access floor of the clean room is sucked by the dust remover installed under the floor from the suction port provided on the floor around the equipment, so that the local air is removed. A local high-cleaning system for purification has been proposed. However, in this case as well, if the layout of the equipment in the clean room is changed as described above, the base for installing the equipment installed on the floor slab and the dust remover installed under the base will be moved together. It is necessary and hassle-free. In addition, it is necessary to provide a perforated panel that is a suction port so as to surround the periphery of the device, and rearrangement of the floor panel also leaves restrictions on the arrangement.

  Further, in the clean room return air device including the fan filter unit 72 (hereinafter referred to as FFU) disclosed in Patent Documents 3, 4, 5 and FIG. 8, the air purified by the FFU 72 installed on the ceiling of the clean room 52. Is sent into the clean room 52, and air dirty in the clean room 52 is sucked from the upper floor surface 55 and circulated. Some air circulation shafts 76 are provided with heat exchangers 74.

  In the air supply device of this structure, if the device cost is increased as a whole and the layout of the device is changed, the flow of air in the clean room changes, and there is a possibility that unevenness of the clean area occurs as described above. Therefore, it was necessary to change the position of the perforated panel and adjust the opening of the shutter.

  The present invention has been made in view of the above-described problems of the prior art, and even when the layout is changed frequently, there is no bias in the cleanliness of the room, and a stable air purification effect can be exhibited easily. It aims at providing the return air apparatus for clean rooms.

  The present invention removes the air fed by the blower with a filter and then blows air from a clean room air supply device that sends air from the ceiling toward the floor surface, and from the upper floor surface through a perforated panel having a through hole. In a clean room return air device that sucks air and introduces it again into the air supply device and circulates and purifies it by a blower and a filter, the perforated panel that forms the upper floor surface and has a through hole that can be vented, the upper floor surface and the floor A clean room return air device comprising a plurality of return air ducts provided between slab surfaces, and a plurality of suction ports provided at end portions of the respective return air ducts and located in a predetermined range of the upper floor surface. It is.

  The suction port opens in the vertical direction at the end of each return air duct. The return air duct is formed in an L shape, and a plurality of the return air ducts are arranged in a predetermined range between the upper floor surface and the floor slab surface, and the suction ports are scattered in the predetermined range. Is.

  According to the clean room return air apparatus of the present invention, the suction air velocity at the suction port on the floor surface is uniform at any location in the clean room, and therefore the air flow velocity distribution in the clean room is uniform, and the cleanliness in the room is not biased. Even if the layout of the equipment installed in the clean room is changed, airflow adjustment is easy. In addition, since the suction air velocity at the suction port on the floor can be made uniform, there is no bias in the air flow in the clean room, there is little recombination of the perforated panel for air flow adjustment, and the arrangement can be performed easily, which improves work efficiency. Good.

  Hereinafter, an embodiment of the return air device for a clean room according to the present invention will be described with reference to FIGS. The return air device 10 of this embodiment sucks air in the clean room 12 and conveys the air to the suction port 42 of the air conditioner 30 of the air supply device 40, and removes dust by the air supply device 40 and supplies the air to the clean room. In order to purify by circulating air. As shown in FIG. 1, the floor structure of the clean room 12 in which the return air device 10 is provided has support members 16 formed on the floor slab surface 14 so as to be adjustable in expansion and contraction. A perforated panel 18 and a non-perforated panel 19, which are floor panels made of cast metal or the like, are placed on a predetermined combination on the upper floor surface 20. The perforated panel 18 is formed with a plurality of through holes 18a through which air can be ventilated. The floor surface can be easily donated to the floor of the upper floor portion by attaching or detaching the panel, or the free access floor 22 can change the arrangement of the panel. It has become.

  A plurality of L-shaped return air ducts 24 are juxtaposed between the floor slab surface 14 and the floor panel, and are fixed to the floor slab surface 14 by a fixture (not shown). As shown in FIG. 2, the return air duct 24 has a plurality of suction ports 26 formed in a rectangular shape on the side surface at the end of the return air duct 24 and perpendicular to the floor surface. Is provided. In the plurality of return air ducts 24, the size of the suction port 26, the cross section of the duct air path, etc. are set so that the total static pressure loss at the suction port 26, the duct air passage, and the relay portion 28 entrance is substantially equal in the air to be conveyed. It is desirable that it be formed.

  One end of the return air duct 24 is connected to a relay unit 28 installed in the lower part of the equipment room 13 adjacent to the clean room 12. It has been. An air blower 32 and a heat exchanger 33 are incorporated in the air conditioner 30 so that the air can be blown upward. A main air supply duct 34 is connected to the air conditioner 30 and extends to the ceiling of the clean room 12. The main air supply duct 34 arranged on the back of the ceiling of the clean room 12 is supported by a hanging tool (not shown).

  Further, a connecting duct 36 is branched and connected to the main air supply duct 34, and the tip of the connecting duct 36 is connected to a blowing portion 38 installed on the ceiling. A blower outlet is formed in the blowout part 38 so as to blow air downward into the clean room 12. In addition, an air filter (not shown) such as a HEPA filter, for example, is incorporated in the blow-out portion 38, and the air can be purified by passing through the air filter.

  Next, the operation of the return air device 10 will be described. First, when changing the layout of the manufacturing process, the devices are rearranged and installed in the clean room 12. At this time, the perforated panel 18 under the device is rearranged with the surrounding non-perforated panel 19 so that the perforated panel 18 is not blocked by the device.

  Thereafter, when the blower 32 is operated, clean air is blown from the blowout portion 38 and air is sucked from the suction ports 26 of the return air ducts 24 provided on the lower side of the free access floor 22. . Then, the air sucked from the clean room 12 through the perforated panel 18 of the free access floor 22 is sent by the blower 32 to the main air supply duct 34 arranged on the back of the ceiling of the clean room 12, and again at the blowout unit 38. It is purified by an air filter (not shown) and blown out to the clean room 12. The blown air flows through the clean room 12, is sucked from the perforated panel 18 of the free access floor 22, and this is repeated. In this state, as shown in FIG. 3, the range of the air sucked at the predetermined suction air speed by each perforated panel 18 attached to the free access floor 22 is substantially the range of the curve B, which is roughly It covers the required air circulation range. Further, the arrangement of the adjacent air supply device and the return air device and the curved line B are arranged so as to cover all necessary air circulation ranges.

  According to the return air device 10 of this embodiment, the air from the perforated panel 18 is uniformly distributed in the free access floor 22 by the plurality of return air ducts 24 provided under the free access floor 22 and the suction ports 26 thereof. Is inhaled. Therefore, even if the layout of the equipment installed in the clean room 12 is changed, the holeless panel 19 and the holed panel 18 may be rearranged and arranged at approximate positions, and the arrangement work is easy. Further, since there is no bias in the amount of air flow that passes through the holes of each perforated panel 18, the required recombination is less and less time-consuming. Furthermore, air flows evenly in the clean room 12, and stable air purification and cleanliness can be maintained.

  The clean room return air device of the present invention is not limited to the above embodiment. As shown in FIG. 4, the clean room return air device includes an FFU 72 as an air supply device on the ceiling, and is provided from the perforated panel 18 of the free access floor 22. It is also possible to use it in a clean room where air is sucked under the floor and the air in the clean room 12 circulates through the shaft 48 which is the inlet of the air supply device.

  In this case as well, the same effect as described above can be obtained, and the air in the clean room 12 is sucked from the suction ports 26 of the return air ducts 24 provided below the free access floor 22 without being biased depending on the location. . Further, when a shutter is provided on the perforated panel 18, the shutter can be easily adjusted, and a clean room with a uniform cleanliness can be reliably maintained.

  Further, the thickness and length of the return air duct formed under the floor of the clean room can be appropriately set according to the arrangement position and interval of the support. In addition, the shape and size of the air outlet provided at the end of the return air duct can be appropriately set in accordance with the size of the clean room and the device arrangement. Furthermore, the shape and material of each member can be changed as appropriate.

It is a schematic longitudinal cross-sectional view which shows the return air apparatus for clean rooms of one Embodiment of this invention. It is a partially broken perspective view which shows the clean room returned by the clean room return air apparatus of this embodiment. It is a top view which shows the area which the suction duct of the return air apparatus for clean rooms of this embodiment suck | inhales. It is a schematic longitudinal cross-sectional view which shows the return air apparatus for clean rooms of other embodiment of this invention. It is a general | schematic longitudinal cross-sectional view which shows the conventional return air apparatus for clean rooms. It is a partially broken perspective view which shows the clean room returned by the conventional clean room return air apparatus. It is a top view which shows the area which the suction duct of the conventional return air apparatus for clean rooms inhales. It is a general | schematic longitudinal cross-section which shows the other conventional clean room return air apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Return air apparatus 12 Clean room 14 Floor slab surface 18 Perforated panel 18a Through hole 19 No hole panel 20 Upper floor surface 22 Free access floor 24 Return air duct 26 Inlet 30 Air conditioner 32 Blower 33 Heat exchanger 34 Main duct 38 Outlet part 40 Air supply device

Claims (3)

  After the air blown by the blower is removed by a filter, it is blown from a clean room air supply device that sends air from the ceiling toward the floor, and sucks air from the upper floor through the perforated panel with through holes. In the return air device for a clean room that is introduced into the air supply device and circulated and purified by a blower and a filter, a perforated panel that forms the upper floor surface and has a through hole that can be vented, and between the upper floor surface and the floor slab surface A plurality of return air ducts, and a plurality of intake ports provided at end portions of the respective return air ducts and extending over a predetermined range of the upper floor surface. apparatus.   2. The clean room return air device according to claim 1, wherein the suction port is open in a vertical direction at an end portion of each return air duct. The return air duct is formed in an L shape, and a plurality of the return air ducts are arranged in a predetermined range between the upper floor surface and the floor slab surface, and the suction ports are scattered in the predetermined range. The clean room return air device according to claim 1 or 2, characterized in that:

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