JPS6255160B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for muffling noise from a device emitting a noisy gas flow, such as a wind tunnel, and for removing foreign matter contained in the gas flow.

For example, wind tunnels for conducting wave-making experiments are generally large and generate extremely loud noises, and water droplets generated during wave-making experiments are emitted outside along with the airflow emitted from the wind tunnel, making it difficult for neighbors to They tend to cause inconvenience to residents and have a negative impact on adjacent experimental equipment. Therefore, in order to operate this wind tunnel properly, it is necessary to reduce noise and remove water droplets.

As a conventionally known muffling device, there is one as shown in FIG. In other words, the reactive type muffles the noisy air flow through a passage with a sudden change in cross section, the absorption type muffles the air flow through a tube lined with sound-absorbing material, and the plenum chamber type. A type in which an inflow pipe and an outflow pipe are provided in a chamber B so as not to be coaxial with each other, and an air flow is passed through the chamber to muffle the sound is a type in which the air flow is passed into a chamber provided with a buff-full plate C.

However, in the above-mentioned noise reduction device,
In order to improve the silencing efficiency, it is necessary to increase the resistance to the airflow, such as by increasing the bending of the airflow within the device, which has the contradictory condition of increasing the resistance loss. ing.

On the other hand, in the wind tunnel for wave-making experiments as described above, it is desirable to muffle the sound and remove water droplets, but at the same time, in order to save operating costs of the wind tunnel, it is desirable to
The pressure loss in the air passage must be kept small, and therefore it is not appropriate to use the conventional muffling device as described above in such a wind tunnel. The same thing can also be said of devices that perform aerodynamic separation of grains and miscellaneous materials in agricultural production, for example.

In view of the above points, the present invention has been developed in a device that emits a gas flow such as an air flow accompanied by noise. The purpose of the present invention is to provide a device for removing .

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. Although this embodiment has been shown as a noise reduction/water droplet removal device applied to a wind tunnel for wave-making experiments, it can also be applied to an aerodynamic sorting device for grains, etc., as described above.

FIG. 2 shows a noise reduction/water droplet removal device 1 according to the present invention.
FIG. That is, this device has a double cylindrical shape in which two cylindrical bodies 12 with approximately circular cross sections are joined adjacent to each other, and a discharge opening 14 (fifth (see figure)), and the upper open end of each cylindrical body 12 serves as an air outlet 18.

Each cylindrical body 12 can be made of any desired material such as concrete, but in the illustrated embodiment, a sound absorbing panel 22 as shown in FIG. To be more precise, they are assembled into a regular polygonal shape, fastened together, and supported by a metal frame (not shown) provided outside. Sound absorbing panel 22
is equipped with a sound absorbing material 26 made of water-repellent glass fiber,
Its side and outer surfaces are surrounded by a metal frame 28, and its inner surface is covered with a metal mesh material 30. Concrete base 2 at the bottom of each cylinder
As shown in FIG. 4, the upper surface of the container 0 is inclined toward a drain port 34 provided in the center thereof, and a sound absorbing panel 36 similar to that described above is provided thereon.

As is clear from FIGS. 2 and 5, the air inlet 16 opens at the center of the two cylindrical bodies, and the air flow from the wind tunnel is divided into two, each with its own air flow. The liquid flows into each cylindrical body in a tangential direction.

In the apparatus according to the present invention constructed as described above, the functions of silencing noise and removing water droplets are performed as follows.

That is, as shown in FIG. 5, the air flow from the wind tunnel is introduced into the two cylindrical bodies through the air inlet 16 in a tangential direction to each of the two cylindrical bodies. The inflowing air flows upward while swirling within each cylindrical body, and is discharged to the outside from the outlet 18. At this time, the water droplets floating in the air are subjected to centrifugal force due to the swirling movement of the air, and most of them hit the inner surface of the cylindrical body and are collected, flow down the inner surface, and exit from the discharge port 34. released. On the other hand, the noise radiated from the wind tunnel discharge opening 14 is
Sound is absorbed by the sound absorbing panels 2 and 12, and the noise radiated from the air outlets 18 and 18 is sufficiently reduced. In order to reduce the noise radiated from the air outlet 18 to a required value or less, parameters such as the height of the cylindrical body and the material of the sound absorbing material may be designed to the required values. Furthermore, the cylindrical body exhibits not only a sound absorption effect but also a sound insulation effect at a point horizontally distant from the wind tunnel's discharge opening 14, and as a result, it also has a very good sound silencing effect on nearby facilities and private houses of the wind tunnel. You can get something big. Therefore, in this respect, it is not necessarily necessary to make the cylindrical body or the inside thereof from a sound-absorbing material.

In the illustrated embodiment, due to the height of the wind tunnel, the air inlet is not provided at the bottom of the cylindrical body, but somewhat above it. For this purpose, the upper surface 40 of the air inlet 16 is inclined inward and downward, as shown in FIG. The parts are used effectively.

In addition, in the above embodiment, the cylindrical body is of a bicylindrical type, but this reduces the resistance within the device by guiding the air flow released from the wind tunnel into as wide a space as possible. This is to reduce the flow velocity of the air flow within the device and make it easier for water droplets to sink due to their own weight, but the same effect can be obtained if the cylindrical body is made of a single cylinder type with a large diameter. Can be done.

The device according to the present invention was operated at a rotation speed of 980 rpm and an air volume of 980 rpm.
When an experiment was applied to a wind tunnel equipped with a 5400 m ³ /min blower and a wind tunnel internal pressure (total pressure) of 110 mmAq, the following results were obtained. The configuration of the device according to the present invention in this experiment was the same as in the above-mentioned example, but the sound-absorbing panel was a 50 mm thick water-repellent panel commercially available from Nippon Sheet Glass Co., Ltd. under the trade name "Floating Wool." Each cylindrical body was made of glass wool sound absorbing material and had a diameter of 7 m and a height of 7.7 m.

(a) Sound deadening effect In the above wind tunnel, the noise level at a point 150 m horizontally away from the air release opening 14 of the wind tunnel (i.e., the boundary of the experimental site) is in the range of 250 Hz to 1000 Hz, and is a so-called sensory-corrected noise level. 55dB～
It was estimated that the noise level was 60 dB or more, which exceeds the noise standard for ordinary homes of 55 dB, but as a result of installing the device according to the present invention, the noise level was reduced to about 42 dB.

(b) Water droplet removal effect Most of the water droplets in the airflow from the wind tunnel are removed, except for very small ones, and the amount of water droplets released from the air outlet of the cylindrical body is much smaller than that of the cooling tower. I was able to do that.

(c) Energy loss If the current silencing method is adopted, it is expected that there will be a pressure loss of about 50 mmAq and an energy loss of about 50 KW in terms of power, but with this device, there is almost no difference when measured by power consumption. I was able to make it as small as possible.

As mentioned above, in the device according to the present invention,
The airflow emitted from the wind tunnel is released to the outside by simply changing the linear motion into a circular or swirling motion, and as in the conventional sound muffling device, the direction of the airflow is changed many times to muffle the sound. Compared to doing
The energy loss is very small, and the required noise reduction and water droplet removal can be achieved without increasing operating costs.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram of various types of noise muffling devices; Fig. 2 is a perspective view of a muffling/water droplet removing device as an embodiment of the present invention; Fig. 3 is a sectional view of a sound absorbing panel; FIG. 5 is a plan principle view of the device shown in FIG. 2; FIG. 6 is a partially cutaway side view of the device shown in FIG. 2. 10... Sound deadening and foreign matter removal device in gas flow,
12... Cylindrical body, 14... Gas flow discharge opening, 16
...Inlet, 18...Outlet.

Claims (1)

[Claims] 1. A device for muffling noise in a device emitting a noisy gas flow and removing foreign matter from the gas flow, such as a wind tunnel, comprising at least one cylindrical body set approximately vertically. , a lower portion of the side wall of the cylindrical body is provided with an inlet connected to the gas flow discharge opening for introducing the gas flow into the cylindrical body in a substantially tangential direction; The upper end of the cylindrical body is opened to discharge the gas flow that enters from the inlet and flows in a spiral shape to the outside, and the lower end of the cylindrical body is a closed end for the gas flow, and the closed end is provided with a gas flow that is removed from the gas flow. A discharge port is provided to discharge foreign matter to the outside, and
A sound-absorbing material is attached to the inner surface of the cylindrical body, and a device for removing foreign matter from a gas flow.