JPH05748Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to clean room and broadcast equipment.

[Conventional technology]

When installing broadcast speakers in a clean room with a HEPA filter on the ceiling, conventionally the speakers were installed in a position facing the room. In this case, there were cases where it was installed on the ceiling surface and cases where it was installed on the wall surface (partition, etc.).

When installing a speaker on the ceiling, there is a method of replacing part of the HEPA filter on the ceiling with a blind plate and attaching the speaker to this blind plate, for example, as shown in Japanese Patent Application Laid-Open No. 138635/1983. To,
A method is known in which a HEPA filter is installed within the width of a ceiling frame that supports it (for example, as shown in Figure 4 of the same publication).

[Problem that the invention aims to solve] Speakers are charged with static electricity, so if they are installed in a position facing the interior of the room, there is a risk that they will pick up dust in the room, and that dust will fall off due to the vibrations of the speakers, contaminating the clean room. . Traditionally, this risk has been ignored. In addition, in the former example where the speaker is installed on the ceiling, it is necessary to
The installation area of the HEPA filter is restricted, and the blown airflow stagnates in this speaker area, making it impossible to achieve the unidirectional flow that is a characteristic of the vertical laminar flow system. Furthermore, if the speaker is installed within the width of the latter ceiling frame, the speaker will be very small, resulting in insufficient volume. In both of these methods, since the speaker is exposed on the ceiling surface facing the room, there is a risk that dust adhering to the speaker may fall into the room due to the vibration of the speaker.

Even if a speaker is installed on a wall such as a partition, it will still accumulate dust. In this case, the installation location is restricted to a place where a partition or the like exists, and the degree of freedom in installation is reduced.

The present invention aims to solve such problems in clean rooms.

[Means to solve problems]

According to the present invention, in a clean room where a HEPA filter layer is placed on the ceiling and clean air is supplied into the room through this HEPA filter layer, the sound source is located above the HEPA filter layer and where the sound is heard. The present invention provides a clean room broadcasting facility characterized in that a broadcasting speaker is installed at a position where the information passes through the HEPA filter layer. In other words, the inventors of the present invention found that the sound at the frequency of normal audio broadcasting is very easy to pass through a HEPA filter, and the transmission loss in a HEPA filter is very small. The above problem is solved by broadcasting through the layers.

〔Example〕

Figure 1 shows the present invention for a clean room in which a HEPA filter 2 is horizontally stretched over the ceiling of a room 1 using a ceiling frame material 3, and the space above the ceiling above the HEPA filter 2 is used as a supply plenum. This is an example of applying the method. In this case, in the supply plenum in the attic space, you can use hanging bolts 4 to hang the ceiling frame material 3, or use a base material 5 (soft iron base, catwalk, etc.) to attach the speakers 6.
Install. That is, the speaker 6 is installed in the ceiling above the HEPA filter 2, which is hidden from the room by the HEPA filter 2, using a member for supporting the HEPA filter 2. When using a horizontal beam 7, a horizontal beam 7 is spanned over the hanging bolt 4, the speaker 6 is attached to this, and the wiring is carried out along the frame 3 under the ceiling. When the base material 5 is used, the wiring may be placed along the base material 5. In any case, the speaker 6 and wiring will be located in the supply plenum in the ceiling, and even if the dust that adheres to them falls off or becomes a dust pool, it will be collected by the HEPA filter 2. , so it won't contaminate the room.

Figures 2 and 3 show that a large number of fan filter units 10 each having a HEPA filter 2 attached to the lower opening of a casing 9 housing a fan 8 are arranged on the ceiling so that the HEPA filters 2 are oriented horizontally. An example is shown in which a speaker 6 is attached to the casing 9 when a clean room is constructed. That is, a speaker box 12 is airtightly provided on the upper plate 11 of the casing 9, and the speaker 6 is disposed within the speaker box 12. The spaces within the speaker box 12 and the casing 9 communicate with each other and are maintained at the same air pressure.

Figure 4 shows the speaker 6 as shown in Figures 2 and 3.
This table shows the measurement results of the sound pressure level with and without HEPA filter 2 installed. The HEPA filter used in the experiment has an area of 1200 x 600 mm and a thickness of 80 mm.
It has a conventional structure in which glass fiber lumber is folded multiple times with aluminum separators in between, and the collection efficiency for particles of 0.3 μm is 99.999%. The experiment is
While operating the fan 8, a microphone was installed indoors 20 cm away from the position of the HEPA filter 2, and the sound from the speaker 6 (white noise; each frequency The sound pressure level (dB) is measured by generating a noise uniformly containing the noise of As seen in the results in Figure 4, when a HEPA filter is present, the sound is reduced by about 5 dB at frequencies above 2KHz, but there is almost no sound reduction in the frequency range below that. I understand that. Note that the background noise in FIG. 4 is unavoidable sound in the clean room other than the sound emitted from the speakers. Furthermore, when actually listening, there was no significant difference in the clarity of the sound from the speakers depending on whether a HEPA filter was installed or not.

[Function and effect of the idea]

As described above, according to the present invention, it has been found that the HEPA filter does not reduce the sound of broadcasting, and that by placing the speaker in the space where the air exists before passing through the HEPA filter. As a result, it is possible to prevent the speaker from becoming a source of dust in a clean room where it is necessary to create an ultra-clean space, and the selection of speaker installation positions has been greatly expanded, making it possible to install the speaker where it is needed. In addition, the broadcasting equipment is effectively prevented from impairing the functions of the clean room, such as without damaging the aesthetic appearance and making wiring easier.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view showing an example of the present invention in which a speaker is installed in a clean room with a supply plenum in the ceiling, and Fig. 2 is a schematic cross-sectional view showing an example of the present invention in which a speaker is installed in a fan filter unit.
FIG. 3 is a plan view of FIG. 2, and FIG. 4 is a diagram showing measurement results of sound pressure levels with and without a filter in the speaker installation examples of FIGS. 2 and 3. 1...Clean room interior, 2...HEPA filter, 3...Ceiling frame material, 4...Hanging bolt, 5...Front material, 6...Speaker, 7...Horizontal beam material, 8...Fan, 9... Casing, 10...
Fan filter unit, 12...Speaker box.

Claims (1)

[Scope of utility model registration request] A HEPA filter layer is placed on the ceiling surface, and this
In a clean room where clean air is supplied into the room through a HEPA filter layer,
Broadcasting equipment for a clean room, characterized in that a broadcasting speaker is installed at a position above a HEPA filter layer and at a position where sound passes through the HEPA filter layer.