JP3013098B2 - Filter unit for ceiling system - Google Patents

Description

The present invention relates to a filter unit, and more particularly, to a filter unit.
The present invention relates to a ceiling system filter unit provided on a ceiling of a clean room.

(Prior art) In recent years, super clean rooms (hereinafter abbreviated as SCRs) have become larger and larger as semiconductor manufacturing lines and the like have become larger and more sophisticated, and the airflow distribution in the rooms has to be ensured with high cleanliness. Is required to be even more uniform.

There are two types of SCR systems that minimize the turbulence area: a full ceiling system and a tunnel system, but they have advantages and disadvantages in terms of energy saving, space saving and flexibility.

The conventional full ceiling system has excellent flexibility in the cleaning area, such as the freedom of the cleaning area and the change of the partition accompanying the line change.However, as the system becomes larger, the arrangement of filters or the branching of the intake duct is increased. In order to send all air volume of air-conditioning and cleaning at once because of lack of uniformity of surface wind speed distribution of filter,
Since the blower becomes large and the branch of the duct and the noise suppression chamber are attached, it becomes a high static pressure and high output blower system, and energy saving cannot be achieved.In addition, due to the large air volume, air conditioners, blowers, etc. There were inconveniences such as the additional equipment becoming larger and the installation space requiring a larger area.

On the other hand, in the tunnel system, the air in the clean room is circulated directly through the return duct (local return system) by dividing the total circulating air volume into two systems, the air conditioning air volume and the cleaning air volume.
Significant energy savings can be achieved compared to the full-height duct return method of the full ceiling system, but there is a disadvantage that there is no flexibility to respond to changes in the production line and process.

In consideration of the above, a unit system with a fan (blower) that combines the advantage of the flexibility of the full ceiling system with the advantage of energy saving by the local return system of the tunnel system is adopted to save energy and space. In addition to the flexibility, the distribution of the airflow blown from the filter is made uniform and the noise is reduced.

For example, Japanese Patent Application Laid-Open No.
2. Description of the Related Art A clean air blower disclosed in Japanese Patent No. 228827 is known. This clean air blower covers an entire area of a dust collecting filter provided at an air outlet of a chamber connected to a discharge side of a blower, and has an air rectifier disposed close to an upstream surface thereof, and an air conditioner. A sound absorber that partitions an air passage is provided upstream of the air absorber with a predetermined air gap between the fluid and the fluid.

Regarding air rectification in this air blower, the discharge airflow flowing into the chamber from the discharge port of the blower diffuses in the chamber, the inertia of the airflow decreases, the wind speed decreases, and the air rectifier By flowing into the surface of the air rectifier through a relatively narrow ventilation gap (10-35 mm in the example) from the entire circumference between the air absorber and the sound absorber, the variation in wind speed at each point around the ventilation gap is reduced. In other words, the wind velocity distribution is uniform, and the pressure distribution in the ventilation passage is also uniform.

As for the noise reduction in this air blower, the area of the sound absorber is set to at least 0.8 times the area of the air rectifier, so that the sound absorbing function of the sound absorber is fully utilized and Is set to be sufficiently smaller than the ventilation area of the filter, so that the amount of noise transmitted to the filter through the ventilation gap can be reduced.

In addition, as the above-mentioned unit type,
A clean air device disclosed in Japanese Patent No. 40569 is also known. This air purifying apparatus includes a blower housed in a casing, a filter disposed in front of the blower, and a front wall of the blower and a rear side of the filter, with a predetermined gap from one wall surface of the casing. It has a configuration in which a blind plate is provided and the flow path of air blown out from the blower is made sufficiently long. Thereby, in this air purifying device,
Although the dynamic pressure of the airflow immediately after discharge from the blower is not uniform, the dynamic pressure is gradually weakened while passing through the flow path, and the entire surface of the filter is gently formed while forming a uniform wind speed distribution. As a result, the noise is reduced and the blowing performance is said to be high.

(Problems to be Solved by the Invention) However, in the ventilation gap generally formed between the sound absorber and the filter, the central portion is governed by dynamic pressure (wind speed), and the peripheral portion is governed by static pressure. JP-A-62-22
In a structure in which a ventilation opening is provided around the entire sound absorbing body, as in the clean air blower disclosed in Japanese Patent No. 8827, since the dispersion in the vertical direction with respect to the main airflow is poor, the filter is governed by static pressure. In addition to the problem that ventilation to the peripheral portion is poor, noise propagates from the entire periphery of the sound absorber to the filter for the same reason, so that the sound absorbing function of the sound absorber is not sufficient.

Further, in the clean air device disclosed in Japanese Patent Publication No. Sho 63-40569, the air flow discharged from the blower gradually becomes static pressure, and the wind speed distribution becomes gradually uniform, but it is not sufficient.

Therefore, an object of the present invention is to provide a ceiling system filter unit capable of obtaining a high rectifying effect and a sound absorbing effect.

(Means for Solving the Problems) A filter unit for a ceiling system according to the present invention comprises: a dust collecting filter; a chamber mounted on the dust collecting filter;
A blower built in the chamber, a sound absorber disposed between the dust filter and the blower, and disposed opposite to the dust filter with a predetermined ventilation gap upstream thereof, and the sound absorber and the blower And a pair of ventilation zones formed only between the chamber surface facing the discharge port and the opposed surface, and the sound absorber has a ventilation area of the chamber.
It is characterized by having an area of 0.88 times to 0.96 times.

(Operation) In the ceiling system filter unit of the present invention, the ventilation zones provided around the sound absorber are arranged at two opposing portions, so that the main airflow is well dispersed in the vertical direction, and the As a result, the rectification effect and the wind speed balance are extremely improved, and for the same reason, only two opposing parts around the sound absorbing body are opened as ventilating zones. Noise does not propagate to the filter from all around the sound absorber as in the example, and the sound absorption efficiency is improved.

Hereinafter, a filter unit for a ceiling system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of a filter unit for a ceiling system according to an embodiment of the present invention, in which reference numeral 1 indicates a filter unit.

Although not shown, the filter unit 1 is arranged on the ceiling of a clean room, and is provided with a dust collecting HE.
A PA filter 2 is provided. A chamber 3 is mounted on the filter 2. Here, the filter 2
Is naturally disposed at the air discharge port of the chamber 3, and a gasket 4 for preventing air leakage is disposed between these peripheral portions. This gasket 4 is attached to the upstream side of the filter 2.

A blower 5 is fixed to the upper inside of the chamber 3 (that is, the blower 5 has a built-in chamber), and the blower 5 indicates air by an arrow A (see also FIG. 2). And a discharge port 5a for discharging in one direction. A sound absorber 6 is provided between the blower 5 and the filter 2 so as to be opposed to the upstream side of the filter with a predetermined ventilation gap 7 therebetween. As shown in FIG. 2, the sound absorbing body 6 extends over the entire width of the chamber 3 in a direction perpendicular to the arrow A which is the air discharge direction of the blower 5. In the opposite direction, it does not extend to the chamber surface, that is, a gap is provided between the edges 6a, 6b and the chamber surface to form a pair of ventilation zones 8, 9
Are formed. That is, the ventilation zone is provided by the sound absorber 6.
And only between the chamber surface facing the discharge port 5a of the blower 5 and the facing surface. The sound absorbing body 6 includes a plate-shaped sound absorbing material 10 and a shielding plate 11 disposed on the filter 2 side. Further, as shown in FIG. 1, the sound absorbing material 12 may be provided on the peripheral surface of the chamber 3.

The area of the sound absorber 6 is desirably 0.8 times or more the ventilation area of the chamber 3 in order to sufficiently exhibit the sound absorbing effect of the sound absorber.

Next, a specific structure of the above-described filter unit 1 will be described.

It is desirable that the present filter unit 1 be installed in a ceiling system of a clean room and configured as a local return type. The effective height of the plenum of this ceiling system where the filter unit 1 is placed is 1000 mm
In this case, the height H of the chamber 3 needs to be 300 mm or less. For this reason, it is desirable to use a compact, thin 150 mm sirocco fan capable of processing a large amount of air as the blower 5 built in the chamber 3.

If the space is sufficient and the static pressure of the blower is large, noise countermeasures are easy, and if the chamber is reinforced sufficiently,
Vibration suppression is possible, but all are large in size and heavy in weight. For this reason, in this embodiment, the chamber 3 is separated from the filter 2 and has a bent structure without reinforcement. Note that, as described above, the filter 2 and the chamber 3 are integrated by attaching the gasket 4 to the upstream side of the filter, thereby performing a vibration suppression measure. Noise countermeasures are taken by the sound absorber 6 and others.

In consideration of the above, the chamber dimensions are set to 575 mm for the width W, 1185 mm for the depth L, 275 mm for the height H, and the height h of the ventilation gap 7.
Was set to 55 mm, and the widths of the ventilation zones 8 and 9 were changed to 25 mm, 50 mm and 70 mm, and the wind speed V of the air blown out of the filter, the airflow distribution δ, and the noise N on the filter side were measured. The noise of the fan itself is 50
At the time of Hz operation, it was 63 dB. The results are shown in Table 1.

Further, under the same conditions as above except that the sound absorbing material 12 was not installed on the peripheral surface of the chamber 3, the filter blowing wind speed V, the airflow distribution δ, and the filter side noise N were measured.
The blowing air velocity V and the airflow distribution δ were the same as those obtained when the sound absorbing material 12 was installed.
It dropped to 4.2dB.

From the above results, it was found that the uniformity of the air flow distribution and the air volume were determined by the widths of the ventilation zones 8 and 9, and the smaller this was, the lower the wind speed of the air blown out of the filter was and the less the variation of the air flow distribution was. However, as in the device of JP-A-62-228827,
In the case where the ventilation zone is provided around the entire sound absorbing body, the variation of the airflow distribution is undesirably large for the above-described reason. Further, while the filter-side noise of the device disclosed in Japanese Patent Application Laid-Open No. 62-228827 was 57 to 62 dB, in the device of the present invention, even when the sound absorbing material 12 was not provided, it was 54.2 dB, and the sound absorbing efficiency was reduced. Improved. Incidentally, the above JP-A-62-228827.
Like the No. device, a ventilation zone is formed around the sound absorber,
Except that the width was 30 mm, the structure was the same as that of the above example (without the sound absorbing material 12), and the noise on the filter side was measured.

The height h of the ventilation gap between the filter and the sound absorber is h
As shown in the embodiment, the optimum is about 55 mm, but 30 to 100 m
m. Outside this range, variations in the wind speed distribution are undesirably widened to about 25 to 30.

(Effects of the Invention) As described above, the filter unit for a ceiling system of the present invention can be made compact and lightweight, and can secure a desired filter blowing wind speed without using an air rectifier, and can maintain an airflow distribution. Can be made uniform,
It is also excellent in the sound absorbing effect of the fan noise.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a filter unit for a ceiling system according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line BB of FIG. 1 ... Filter unit, 2 ... Filter, 3 ... Chamber, 5 ... Blower, 6 ... Sound absorber, 8,9 ... Ventilation zone.

Claims (1)

(57) [Claims] 1. A dust collecting filter, a chamber mounted on the dust collecting filter, a blower built in the chamber, and disposed between the dust collecting filter and the blower, and disposed upstream of the dust collecting filter. A sound absorber disposed opposite to a predetermined ventilation gap, and a pair of ventilation zones formed only between the sound absorber and a chamber surface facing the discharge port of the blower and the facing surface thereof, The sound absorber has an area that is 0.88 to 0.96 times the ventilation area of the chamber, and is a filter unit for a ceiling system.