JP2015068562A - Fan filter unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clean room with high cleanliness.SOLUTION: A fan filter unit has a motor for rotating a fan runner, the fan runner, a filter, and a housing. The fan runner is disposed between a top plate which is an upper surface of the housing and the filter in the housing, generally in parallel with the top plate. A diffusion member has a filter attaching portion, and the filter is attached to the filter attaching portion of the diffusion member. The diffusion member attached with the filter is installed on a lower surface of the housing, and has a folding portion on at least one part of an end portion.

Description

  The present invention relates to a clean room fan filter unit installed in a semiconductor factory, food factory, pharmaceutical factory or the like.

  Conventionally, a fan filter unit (air) that is installed in a ceiling opening of a clean room or the like that blows clean air from the ceiling surface and sucks and circulates from the wall surface to increase the cleanliness of the room and attaches a perforated plate to the lower surface outlet of the fan filter unit. Cleaning devices) are known. Further, in the fan filter unit, a shape in which the perforated plate is chevron for diffusion of the blown air, a structure in which a square slit is provided on the side of the blowout surface to diffuse the air in the lateral direction, and a double porous plate is provided. Structures for diffusing air are known.

  As a prior art, Patent Document 1 (Japanese Utility Model Publication No. 63-150236) states that “the air filter unit is positioned at the opening of the ceiling plate and is airtightly fixed to the periphery of the opening by the unit frame. In a clean air blowing device in which a lower blowing perforated plate is provided on a lower opening surface of a unit surrounding frame, the unit is interposed between an air filter in the unit surrounding frame and the perforated plate and between a central surface area of the perforated plate. A baffle plate is provided with a space in between, and a horizontal blowout hole is provided in the surrounding frame surrounding the upper surface space of the perforated plate, and a frame-shaped shutter provided along the surrounding frame is connected. Connected to the operation member provided outside through the member, the frame-shaped shutter is moved up and down in conjunction with the operation of the operation member, and the opening and closing of the horizontal blowout holes arranged around the surrounding frame can be adjusted Clean air blowing device Is described.

  Patent Document 2 (Patent No. 3746120) states that “the supply port is provided at the lower portion of the supply port of an air supply box that is installed on a ceiling surface of a clean room and in which a filter is attached by a filter fixing rod. A container-shaped internal diffusion unit that is disposed so as to cover a large number of small holes on the outer surface, and is disposed at the lower part of the ceiling surface so as to cover the internal diffusion unit, and a large number of small holes are formed on the outer surface. A container-shaped external diffusion unit, and the internal diffusion unit has an upper surface frame attached to the filter fixing rod protruding from the lower surface of the filter and abutting on the periphery of the lower surface of the filter. An air blowing device for a clean room ”is described.

Japanese Utility Model Publication No. 63-150236 Japanese Patent No. 3746120

  According to Patent Document 1, air blown from the fan becomes clean air through this air filter, is diffused by the perforated plate on the lower surface of the apparatus, and blows out into the clean room. Further, in order to diffuse in the lateral direction, a rectangular slit is provided on the side surface of the blowing surface to diffuse the airflow. By driving the fan, air is sent into the air filter unit at a predetermined air volume and blown into the room through the blowout perforated plate below the air filter. Also, a baffle plate (baffle plate) is provided in the space between the air filter and the perforated plate, and the blown air once strikes the baffle plate and flows in four directions in the lateral direction, and passes through the rectangular slit formed on the outer peripheral surface of the perforated plate. It is diffused by changing the wind direction in the horizontal direction. At this time, the air flow in the downward direction becomes weak, and if the air volume is increased, the air further spreads in the lateral direction, and the portion directly below the center tends to become weak, which causes turbulence.

  In the fan filter unit according to the prior art, the clean air blown from the perforated plate is blown into the clean room, turbulent flow is generated in the clean room, and an appropriate cleanliness cannot be maintained. In a clean room that requires high cleanliness and does not like turbulent flow, a downflow clean room is formed, but a fan filter unit is placed on the entire clean room to form a downflow. Also, running costs and maintenance costs for operating the equipment are high.

In particular, in a conventional clean room, the area where the fan filter unit is installed is smaller than the room area, so clean air can be efficiently diffused into the room and discharged outside without creating a turbulent flow area. It is important to maintain a stable cleanliness. In particular, it is important not to form the turbulent flow portion within about 2 m from the floor, which is the work area. It is common to use a chevron-shaped perforated plate instead of a flat perforated plate in order to achieve an air flow diffusion effect. However, because of its complicated shape, it takes a lot of processing steps to form and is very expensive. It will be a thing. Moreover, since the air flow diffusion effect is not sufficient and the wind speed distribution is poor, there is a possibility that a turbulent flow portion is generated in the clean room. In addition, since the mountain-shaped perforated plate protrudes from the indoor ceiling, there is a problem that the beauty is also impaired. Since these problems are not recognized as problems, they are not disclosed in the patent literature.
The object of the present invention is to provide clean air with high cleanliness.

  To achieve the above object, a fan filter unit of the present invention is a fan filter unit having a motor for rotating a fan runner, a fan runner, a filter, and a housing. The diffusing member has a filter attaching portion, and the filter is attached to the filter attaching portion of the diffusing member. The diffusion member to which the filter is attached is installed on the lower surface of the housing, and further has a bent portion at least at one end portion.

  Further, the bent part is characterized in that it is bent to the side in a direction different from the housing side.

  It has a filter case that covers the housing and the diffusing member, the bottom surface of the filter case is punched, and the side surface portion is provided with an opening at a position lower than the bent portion.

  According to the present invention, clean air with high cleanliness is provided by the fan filter unit having the configuration of the present invention.

The longitudinal cross-sectional view and cross-sectional view of the fan filter unit which show 1st Embodiment of this invention are shown. The corner part enlarged view of the lower surface blowing part of the fan filter unit which shows 1st Embodiment of this invention is shown. The airflow diffusion plate attachment part which shows 1st Embodiment of this invention is shown. The analysis result of the air flow of this invention is shown. An example of a conventional structure is shown. The analysis result of the air flow of a conventional structure is shown. The example using the angle-shaped punching of the conventional structure is shown. The analysis results of the air flow of an example using a conventional angle punching plate are shown. The input part showing the setting of the section calculation of analysis conditions is shown. The analysis range of analysis conditions is shown. The example of the figure which looked at the diffusion plate from the upper part is shown. The example of the figure which looked at the diffusion plate from diagonally upward is shown.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Example 1
FIG. 1 shows a longitudinal sectional view and a transverse sectional view of a fan filter unit showing Embodiment 1 of the present invention. FIG. 2 is an enlarged view of a corner portion of the lower surface blowing portion of the fan filter unit shown in FIG. FIG. 3 shows an attachment portion of the airflow diffusion plate.

  A conventional clean room fan filter unit generally employs a system in which a building duct is connected to the duct connecting portion 1 and air is supplied from a distance from the duct.

  The fan filter unit is entirely formed of a main body case 2 and a filter case 3, a fan case 4 is disposed therein, a fan runner 5 and a motor 6 are provided in the fan case 4, and the fan runner 5 is an air supply port. The upper part is protected by a certain bell mouth 3. The filter case is disposed so as to cover the housing and the diffusion plate. The bottom surface of the filter case is preferably punched, and the side surface portion is preferably provided with an opening at a position lower than a bent portion described later. The opening will also be described later.

In this embodiment, the fan runner 5 is not particularly limited as long as it is a fan represented by a turbo fan or a fan runner. The fan runner 5 is disposed substantially parallel to the top plate between a top plate which is the upper surface of the housing and a filter which will be described later. A HEPA filter 6 is fixed to the lower part of the fan case 4. The HEPA filter 6 is fixed to the stud bolt 7 welded to the filter case 3 by fastening the diffusion plate 8 with a nut with a seat. That is, the filter is attached to the filter attachment portion of the diffusion plate 8 (diffusion member).
The dust 9 in the air is removed by the HEPA filter 6, becomes clean air, is sent to the secondary side (lower side) of the HEPA filter, passes through the perforated plate 10, and is blown into the clean room. The perforated plate 10 is a full-surface punching plate having a diameter of about φ1 to φ3 and is bent at four sides of about 15 mm, and the bent portion can also serve as a path for airflow. For convenience, the HEPA filter 6 is described as a HEPA filter, but may be another filter represented by, for example, a ULPA filter.

  The diffusion plate 8 is an integrally molded part made of a steel plate, a square hole is opened at the center, and a bent portion having four sides of 20 to 30 ° is formed at the end. It can be manufactured without using integral molding, and may be joined by welding or rivets. However, considering the cost, it is desirable to manufacture by integral molding. The tip of the bent portion is bent so as to face a direction different from the casing, that is, upward.

  The distance between the bent portion and the frame forming the HEPA filter 6 is about 15 mm. Experiments have confirmed that the distance may be between 10 and 20 mm. In addition, it was confirmed that the down flow becomes strong and the diffusion effect becomes weak at a small value of about 5 mm.

A view of the diffusing plate 8 as viewed from above is shown in FIG. The central part of the diffusing plate 8 is a filter attaching part 200, which is adapted to attach a filter. The diffusion plate 8 is installed on the lower surface of the housing.
The diffusing plate 8 has a bent portion 201 at the end in the left-right direction, and has a bent portion 202 at the end in the front-rear direction. When the diffusion plate 8 is attached to the fan filter unit, the bending portions 201 and 202 are bent downward (to the clean room side with the fan filter unit as the center). The angle of the bent portions 201 and 202 may be such that the bent portion is inclined on a curve. That is, the shape may be such that R is given from the bent part to the end part.

  Analysis of the air flow having the configuration shown in FIG. 1 was performed. The result is shown in FIG. The airflow flowing downward from the diffusion plate 8 is blown from the porous plate 10 at a wind speed of about 1 m / s, and the blown air is partially diffused, but a part forms a vortex directly under the porous plate 10 and is porous. It returned to the side surface of the board 10, returned to the square slit 11 on the side surface of the filter case, and was confirmed to be diffused into the room again. Due to the formation of this airflow, a downflow is formed substantially in the lower part of the perforated plate about 500 mm, and a downflow without turbulent flow can be formed in the vicinity of 1 m below as the work area.

  For comparison with the present invention, an example of a conventional structure is shown in FIG. The HEPA filter 6 is fixed by an L-shaped metal fitting 12 made of a steel plate, and a perforated plate 13 having a conventional structure is provided below the HEPA filter 6. The perforated plate 13 having a conventional structure has a structure in which a whole surface punching plate 14 having an entire surface of about φ1 to φ3 and a punching plate guide 15 obtained by bending a steel plate part are welded.

  FIG. 6 shows the analysis result of the air flow in the example of FIG. 5 showing the above-described conventional structure. The clean air blown out from the porous plate 13 having the conventional structure spreads as it goes downward in the room. Eventually, the turbulent flow part 16 is formed, and the air current becomes stagnation and becomes a factor of accumulation of dust.

  FIG. 7 shows an example in which a chevron punching plate is used in another conventional structure. Conventionally, the chevron punching plate 17 generally used in the case of diffusing an air flow has a punching structure at an inclined portion.

  FIG. 8 shows an analysis result of the air flow of the example using the conventional punching plate having the conventional structure shown above. Although the airflow is diffused indoors from the angle punching plate 17, the wind speed distribution is poor, and the turbulent portion 18 where the airflow is unstable in the room is formed, and the airflow stagnates and becomes a cause of dust accumulation.

  Compared to the conventional structure, the present invention adopting the structure of Example 1 can form the expected downflow as the clean air blown out from the perforated plate 10 spreads the entire airflow having a good wind speed distribution and goes downward in the room. It can be seen that no airflow stagnation occurs.

Further, FIG. 9 shows conditions for analyzing the simple analysis model shown in FIGS.
FIG. 9 shows the conditions to be analyzed, FIG. 9A shows an input unit indicating the setting of the cross section calculation, and FIG. 9B shows the range to be analyzed. In FIG. 9A, when the height direction of the analysis model of the fan filter unit is the y direction, the width direction is the x direction, and the depth direction is the z direction, the number of cross sections is 210 in the y direction and the z direction is 45. When the analysis is performed by dividing the x direction into 150, the voxel size display is about 1.4 million cells, and the analysis range is a range including the entire fan filter unit as shown in FIG. 9B.

  According to the configuration of the first embodiment, in the fan filter unit for a clean room, a downflow is formed in the work space due to a good airflow diffusion effect, and the spray (aerosol) generated in the work space does not roll up efficiently. It is possible to provide a fan filter unit that can suppress generation of turbulence without forming a clean room and arranging the fan filter unit in the entire clean room. In addition, by forming a down flow, it is not necessary to place fan filter units in the entire clean room, so the number of fan filter units can be reduced compared to the conventional case, and the initial cost for equipment purchase and performance maintenance The maintenance cost can be reduced and energy saving can be expected.

  In addition, since a mountain-shaped punching plate having a large number of steps up to production and high cost is not used, it can contribute to cost reduction.

  Further, for example, by applying it to a fan filter unit of a conventional clean room, it is possible to suppress the accumulation of dust due to a part of the turbulent flow region and solve the problem that it is not suitable for a clean room with high cleanliness.

  Further, by appropriately setting the arrangement and area of the airflow diffusion plate, the airflow diffusion effect and the sound insulation effect are exhibited, and the problem that the wind speed is high only under the fan filter unit and a draft is generated can be solved.

  In addition, when forming a clean room, baffle plates such as baffle plates that obstruct airflow do not cause in-machine resistance, and by demonstrating airflow diffusion function, the number of required fan filter units can be reduced, saving energy. Can also contribute.

  In addition, since the mountain-shaped perforated plate does not protrude from the indoor ceiling, it is possible to use the space in the clean room more widely by reducing the space occupancy rate, contributing to improving the design freedom of the clean room. .

The airflow diffusion plate can be expected to have not only an airflow diffusion effect but also a sound insulation effect by setting an appropriate opening area. Also, by fixing a filter represented by a HEPA filter with integrally molded parts, the filter can be Since it can be tightened evenly, it is possible to prevent dust leakage due to poor tightening of the filter.
(Example 2)
Next, FIG. 3 shows an airflow diffusion plate mounting portion showing the form of the second embodiment of the present invention.
The side surface of the filter case has a plurality of square slits of about 10 × 100 mm in width, and the opening area is preferably about 30% of the opening on the lower surface of the filter case as a result of the experiment. The opening may have any shape. For example, the opening may be composed of a plurality of holes, a large single hole, or a combination of holes of a plurality of sizes. The shape may be a round or square hole. For the convenience of manufacturing the mold, it is desirable in terms of cost because a general hole can be processed by making a round hole.

  In FIG. 3, as a result of analyzing the area viewed from the lower surface of the diffusion plate 8 with respect to the opening area of the filter case 3, it is required that the air flow diffusion effect becomes more efficient when the opening area is about 25 to 35%. It was. A sound insulation effect can be obtained more than that of the first embodiment by adopting the configuration of the diffusion plate 8 and the area of the filter case opening 25 to 35%.

  Moreover, since it has an opening part, it can contribute to weight reduction of a filter case. Furthermore, the burden on the operator can be reduced during clean room construction and maintenance.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Duct connection part 2 Body case 3 Filter case 4 Fan case 5 Fan runner 6 Motor 7 Stud bolt 8 Diffusion plate 9 Dust 10 in the air Perforated plate 11 Square slit on the side of the filter case 12 ... L-shaped metal fitting 13 ... Conventional perforated plate 14 Punching plate 15 of φ1 to φ3 · Punching plate guide 16 · Turbulent portion 17 · Punching plate 18 · Unstable turbulent portion 200 · Filter mounting portion 201, 202 .. bent portion at the end of the diffusion plate

Claims (3)

In a fan filter unit having a motor for rotating a fan runner, the fan runner, a filter, and a housing,
The fan runner is disposed substantially parallel to the top plate between the top plate, which is the upper surface of the housing, and the filter in the housing.
The diffusion member has a filter mounting portion,
The filter is attached to a filter attachment portion of the diffusion member,
The fan filter unit is characterized in that the diffusion member to which the filter is attached is installed on the lower surface of the casing, and further has a bent portion at at least one end portion. The fan filter unit according to claim 1, wherein
The fan filter unit, wherein the bent portion is bent in a direction different from the housing side. The fan filter unit according to claim 1 or 2,
It has a filter case that covers the casing and the diffusing member, the bottom surface of the filter case is punched, and the side surface portion is provided with an opening at a position lower than the bent portion. Fan filter unit to be used.

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