JPH08210299A - Muffler for blower - Google Patents

Abstract

PURPOSE: To improve a sound absorbing effect and a sound insulation effect and to simplify cleaning during choking of the sound absorbing material. CONSTITUTION: A light concrete sound absorbing sheet is mounted on the inner side of the casing 11 of a muffler 10 through a damping sheet and a plurality of sound absorbing cylinders 20 filled with a sound absorbing material (glass wool) are removably contained in parallel in a casing 10 and between the outer and inner cylinders of a punching metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for a blower which reduces noise generated from an intake port and an exhaust port of a blower used for ventilation in tunnel construction or the like.

[0002]

2. Description of the Related Art Conventionally, as a silencer for such a blower,
A sound absorber was assembled in a splitter type or a cell type and installed in the casing of a silencer.

[0003]

When a conventional splitter type or cell type silencer is used for a long period of time, dust in the intake air causes clogging of the sound absorbing material. However, since the sound absorbing material incorporated in the casing cannot be removed, cleaning cannot be performed. In addition, there is sound transmission from the duct wall and sound emission due to air flow excitation of the duct wall, in order to prevent this, the duct wall is thickened, or the duct wall outer periphery is subjected to lagging processing, that is, a damping material around the duct wall, a sound absorbing material, There was a problem such as having to perform a winding process with a sound insulation material.

An object of the present invention is to provide a muffler for a blower which improves the sound absorbing effect and the sound insulating effect and is easy to clean when the sound absorbing material is clogged.

[0005]

According to the present invention, a lightweight concrete sound absorbing material is attached to the inner wall of a casing connected to the suction side and the discharge side of a blower via a damping sheet, and at the same time, in the casing. , A plurality of sound absorbing cylinders filled with a sound absorbing material in a double punched metal cylinder are detachably accommodated in parallel.

Further, according to the present invention, a lightweight foam concrete board is used as the lightweight concrete sound absorbing material.

Further, according to the present invention, in the sound absorbing material of the sound absorbing cylinder,
Glass wool is used.

Further, according to the present invention, both ends of the double cylinder of the sound absorbing cylinder are formed in a conical shape whose diameter is reduced toward the inner cylinder.

[0009]

In the muffler of the blower configured as described above, the lightweight concrete sound absorbing material has a greater sound insulation effect, and the damping effect of the damping sheet provides a larger plate vibration damping effect.

Further, since the inner and outer cylinders of the sound absorbing cylinder are made of punched metal, the sound absorbing area is large and a large sound absorbing effect can be obtained with a small pressure loss.

Further, when the sound absorbing material is clogged, the sound absorbing cylinder can be taken out and easily cleaned.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, a muffler 10 is connected to the discharge side of a blower, that is, a turbofan 1 via a reducer 2, and the muffler 10 includes a reducer 3.
The air supply hose 4 is connected via. On the other hand, on the suction side of the turbo fan 1, a silencer 1 is provided via a reducer 5.
0 is connected, and a bell mouth 6 is attached to the muffler 10.

Referring also to FIG. 3, the casing 11 of the muffler 10 is formed of a steel plate having a thickness of 3.2 mm, for example, and the inner wall of the casing 11 has a thickness of 1.5 mm, for example.
Damping sheet, for example, a product name "CAI DAMPER") 12 and a lightweight concrete adsorbent, that is, a lightweight cellular concrete plate having a thickness of, for example, 50 mm (for example, product name "PORECELL" manufactured by Daido Concrete Co., Ltd.)
13 is attached.

Referring also to FIGS. 4 and 5, inside the casing 11 of the muffler 10, a shelf-shaped partition plate 14 having an opening in the flow direction is formed. And these partition plates 1
The sound absorbing cylinders 20 are housed in the respective 4 in a removable manner. That is, the plurality of sound absorbing cylinders 20 are arranged in parallel in the flow direction.

Referring also to FIG. 6, the sound absorbing cylinder 20 is made of, for example, a round element “Sound Trap” manufactured by Mitsubishi Aluminum Co., Ltd. This sound absorbing cylinder 20
Is an outer cylinder 21 of punching metal, an inner cylinder 22 in which both end portions of the punching metal are formed in a conical shape 22a whose diameter is reduced inward, and a double cylinder formed by both cylinders 21 and 22. And glass wool 23 filled in the interior of the.

FIG. 7 shows another embodiment of the sound absorbing cylinder. Diced cone shaped portions 24a and 25a are formed at both ends of the outer cylinder 24 and the inner cylinder 25 of the sound absorbing cylinder 20A, respectively, and the others are the same as in FIG. This is an example of a similar configuration.

Next, the operation will be described.

Since the sound absorbing cylinder 20 is formed with a frustoconical portion 22a and both the outer cylinder 21 and the inner cylinder 22 are made of punching metal, the air resistance is small and the sound absorbing area is large and small. A large sound absorbing effect can be obtained with pressure loss. Further, when the sound absorbing material, that is, the glass wool 23 is clogged, the sound absorbing cylinder 20 can be pulled out and easily cleaned.

Further, since the lightweight cellular concrete plate 13 is attached to the inner wall of the casing 11 via the damping sheet 12, a sound insulation effect and rigidity can be obtained in addition to the sound absorption effect. Also, due to the sliding of the damping sheet 12,
A large plate vibration damping effect can be obtained. Therefore, it is possible to prevent sound transmission and sound emission due to plate vibration without performing the lagging process on the casing 11.

As a result, as shown in FIG. 8, the silencer 1
The noise level of 100 dB (A) when there is no zero can be reduced to 70 dB (A) by the muffler 10.

[0022]

Since the present invention is configured as described above, the sound absorbing effect and the sound insulating effect are improved, and the sound absorbing material can be easily cleaned when it is clogged.

Therefore, the conversation of the tunnel construction worker,
Communication is possible, which greatly contributes to safety and prevention of hearing loss.

When a blower is installed outside the mine,
Effective for preserving the surrounding environment.

[Brief description of drawings]

FIG. 1 is a side view of a turbofan showing an embodiment of the present invention.

FIG. 2 is a top view of FIG.

FIG. 3 is a sectional view of a casing.

FIG. 4 is a view on arrow A in FIG.

5 is a view on arrow B of FIG.

FIG. 6 is a side view showing an example of a sound absorbing cylinder in a cross section of a lower half portion.

FIG. 7 is a drawing corresponding to FIG. 6, showing another example of the sound absorbing cylinder.

FIG. 8 is a band level to 1/1 octave band center frequency characteristic diagram comparing the muffling effect with and without a muffler.

[Explanation of symbols]

 1 ... Turbo fan 2, 3, 5 ... Reducer 4 ... Intake hose 6 ... Bell mouth 10 ... Silencer 11 ... Casing 12 ... Damping sheet 13 ... Light weight air bubble Concrete plate 14 ... Partition plate 20, 20A ... Sound absorbing cylinder 21, 24 ... Outer cylinder 22, 25 ... Inner cylinder 22a, 24a, 25a ... Dice-shaped conical portion 23 ... Glass wool

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuya Ota 2-1-1, Tobita, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (72) Inventor Yokohisa Iyaya 2--19, Tobita, Chofu-shi, Tokyo No. 1 Kashima Construction Co., Ltd. Technical Research Institute (72) Inventor Shoji Noma 1-2-7 Moto Akasaka, Minato-ku, Tokyo Inside Kashima Construction Co., Ltd. (72) Inventor Yoichiro Nakamura 1-chome Moto Akasaka, Minato-ku, Tokyo No. 7 within Kashima Construction Co., Ltd. (72) Inventor Shigehito Uji, 1-chome, Moto-Akasaka, Minato-ku, Tokyo No. 7 within Kashima Construction Co., Ltd. (72) Masaaki Sato, 1-chome, Moto-Akasaka, Minato-ku, Tokyo No. 5 Fujiin Building Kajima Mechatro Engineering Co., Ltd. Inside the company

Claims (4)

[Claims] 1. A lightweight concrete sound absorbing material is attached to an inner wall of a casing connected to a suction side and a discharge side of a blower via a damping sheet, and sound is absorbed in a double cylinder of punching metal in the casing. A silencer for a blower, in which a plurality of sound absorbing tubes filled with material are detachably accommodated in parallel. 2. The silencer for a blower according to claim 1, wherein a lightweight foam concrete board is used as the lightweight concrete sound absorbing material. 3. The silencer for a blower according to claim 1, wherein glass wool is used as the sound absorbing material of the sound absorbing cylinder. 4. The silencer for a blower according to claim 1, wherein both ends of the double cylinder of the sound absorbing cylinder are formed in a conical shape whose diameter is reduced toward the inner cylinder.