JPS60129540A - Low air speed vertical laminar flow type clean room - Google Patents

Abstract

PURPOSE:To permit to blow off air with comparatively low speed into a room by attaching a low airflow amount type filter, necessitating no air filter, to the whole surface of ceiling. CONSTITUTION:A filter 5 is provided with a large pitch, therefore, it is not necessary to be equipped with the separator which prevens the adhesion of neighboring filter paper. The structure of the filter is simple, therefore, it can be manufactured by the frames of synthetic resin board or the like, the weight thereof may be reduced to the degree of 3kg in maximum and the mounting thereof may be simplified very much. Such low flow amount type filter 5 is attached to the whole surface of the ceiling so as to blow off the low speed air having comparatively small passing resistance.

Description

[Detailed description of the invention] [Industrial application field].

The present invention relates to clean rooms used in semiconductor factories, precision machinery factories, etc., and particularly to low wind velocity vertical laminar flow clean rooms.

[Problems to be solved by this invention] Currently, in this type of clean room, dust particles with a particle size of 0.5 μm or more are defined as the number of particles contained in 1 ft of indoor air, for example, 100 particles/ft. “Things in class-1
00,1cioo.

In the case of individual / ftl, it is called class -100'OO.

Such indoor air dust particles can be found in the general atmosphere at a rate of several hundred blades/ftl d, or 100 to 100,000 particles/ft.
As a dust removal device for reducing the amount of dust to
c 1ency Particulate Air Fi
It is well known that filters (lter) are used.

In order to create an ultra-clean space above class-100U using this HEPA filter 1, as shown in Fig. 2,
This HEPA is applied to the entire surface of the indoor ceiling other than where lighting equipment is installed.
The purpose is achieved by installing the filter 1 and creating a vertical airflow from the ceiling to the floor at a uniform wind speed of about 0.25 m/see. This type of system is called a vertical laminar flow clean room.

On the other hand, a class that does not require high cleanliness
In clean rooms from class 1000 to class -100,000, HEPA filters 1 are installed scattered on the ceiling of the room, as shown in Figure 6.
Air is blown out at a wind speed of about /see. According to this method, the airflow blown from the HEPA filter 1 attracts indoor airflow, and the contaminated air in the room and the clean air from the HEPA filter 1 are mixed, and then diffused into the room. This type of lean room is called a turbulent clean room.

In a vertical laminar flow clean room, indoor dust generation is
Riding on the airflow from the A filter, it reaches the suction port on the floor without being diffused elsewhere, but in a turbulent flow clean room, by its very nature, it is impossible to prevent indoor dust from dispersing indoors. .

However, when a very high degree of cleanliness is not required, it is possible to create a clean space with a relatively small amount of blowing air, so conventional turbulent flow clean rooms are used not only in semiconductor factories and precision machinery factories, but also in pharmaceutical factories, etc. It was also widely used in food factories. By the way, the air volume in a vertical laminar flow clean room is approximately 600 to 500 ventilation times/hr, but in a turbulent flow clean room, the airflow rate is approximately 600 to 500 times/hr.
0 ventilation frequency 100 times/hr, class -100,000
20 times/hr, the cost of air conditioning equipment is much lower than that of a laminar flow clean room.

These clean rooms have their advantages and disadvantages, but as clean rooms become more widespread in various industries in the future, it would be advantageous if they could be made inexpensive and relatively clean.

[Purpose of the invention]

This invention was proposed in view of the above circumstances, and its purpose is to provide a low wind speed, straight laminar flow type clean room that has a relatively simple configuration, is inexpensive, and has a low wind speed and relatively high cleanliness. There is a particular thing.

[Structure of the invention]

In the clean room according to the present invention, a commercially available HEPA filter in which filter paper is folded into a wave shape is used as a low air volume filter that has a relatively large pitch of filter paper and does not require a separator, and this low air volume filter is used to cover the entire ceiling surface. It is installed over the whole area and blows air into the room at a relatively low wind speed.

〔Example〕

The present invention will be described below based on an illustrated embodiment. First, to explain the conventional HEPA filter 1 on the market, as shown in Fig. 1, a filter paper 3 mainly made of asbestos or glass wool is folded into a wave shape at a pitch of about 5ml1I inside a wooden frame or steel plate frame 2. installation,
Separators 4 made of corrugated aluminum or the like are alternately inserted to maintain the spacing between the filter papers and to increase the filtration area.

Table 1 shows an example of the dimensions, performance, etc. of such H]liCP A filter 1.

Table 1 The passing wind speed of such a HEPA filter 1 is very slow, for example, in the case of type A = '0.0' 141 Cm/5ec), and its passing resistance is approximately 251111 A% at an initial value.

Table 2 shows an example of the amount of air processed by an air conditioner in a general turbulent clean room. Here, the indoor ceiling height is 2
．． It is set at 5m.

Therefore, if the air volume shown in Table 2 is to be processed by a HEPA filter installed on the entire ceiling, the HEPA
Considering ineffective parts such as the filter mounting frame, if we use the type A filter frame shown in Table 1 to cover a ceiling area of 0.5 m2, the processing air volume of each of the 41 filters a and b is class 1000. : 200XO, 5=10
0m/hr・pcs 10000: 100XO, 5=501
+L/hr-pcs□1QOQQ0: 37.5xQ, 5=
17.75 m”/hr.

For such a processing air volume, the maximum passing air speed is set to 0.01.
4111t/see, 10 Q tri”/
The material area required to process hr.pieces is ≠1.97 (filter material length = 1.9710) .6', 3.5m is sufficient.

Therefore, if the effective height of the filter medium is approximately 206 IIL, the number of folds in the filter medium will be 16 and the number of ridges will be 8, and the pitch between the ridges will be 753111 as shown in Figure 4.
Thus, a low air volume filter 5 can be obtained which is approximately 1010 times larger than conventional commercially available HEPA filters.

With such a filter 5, since the pitch is large,
There is no need for a separator to prevent adhesion of adjacent papers as in the conventional method.

In addition, since the filter 5 has a simple structure, it can be manufactured using a frame made of synthetic resin plate instead of conventional wood or steel plate.
A device having a weight of f is reduced to a weight of about 3 to 9 at most, and its installation becomes extremely easy.

As shown in Figure 5, such a low air volume type filter 5 is attached to the entire ceiling (excluding parts such as mounting brackets and lighting equipment) so that air can be blown out at the aforementioned low wind speed with relatively low passage resistance. By doing so, a low wind speed vertical laminar flow clean room can be easily obtained.

Although the above example shows one calculation example, the length of the filter medium can take various values depending on the filter type, processing air volume, etc., but it goes without saying that a filter 5 with a large pitch can be obtained in any case. .

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a low wind speed, vertical laminar flow type clean room with a relatively simple structure, low friction, low wind speed, and relatively high cleanliness. Furthermore, the low air volume filter can be lightweight,
It has the advantage of being very easy to install.

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional HEPA filter, Figure 2 is a schematic diagram of a conventional vertical laminar flow clean room, and Figure 3 is a perspective view of a conventional HEPA filter.
FIG. 4 is a schematic diagram showing a conventional turbulent flow clean room, FIG. 4 is a schematic diagram showing a filter according to the present invention, and FIG. 5 is a schematic diagram showing a clean room according to the present invention. 1... HEPA filter 2... Frame 3
...Filter paper 4...Separator 5...
...Low air volume filter

Claims (1)

[Claims] (゛) A low-airflow type filter in which each piece of filter paper folded into a wave shape is relatively large and does not require a separator is installed over the entire ceiling, allowing relatively low wind speeds. A low wind velocity vertical laminar flow clean room that blows air into the room. (2) A low wind speed vertical laminar flow clean room according to claim 1, wherein the pitch of the low air flow filter is determined based on the cleanliness of the turbulent flow clean room.