JP2001182700A - Axial blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial blower restraining the degradation of muffling performance due to a secular change and being suitabale for ventilation in a tunnel. SOLUTION: In this axial blower 10 having a cylindrical noise eliminating casing 11, an electric motor 12 arranged by adjusting the axis to the center of the noise eliminating casing 11 and an impeller 13 arranged on an output shaft, the muffling casing 11 is provided with an inner cylinder 16 composed of a porous plate formed with a large number of small holes 20 at prescribed intervals, a thin plate-like porous sound absorbing material 18 being arranged in a state of contacting with the outside of the inner cylinder 16 and an outer cylinder 17 arranged by having clearance outside the porous sound absorbing material 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial blower having a single-stage or a plurality of stages of impellers installed in a tunnel or the like, and more particularly to a high-efficiency axial-flow blower which suppresses deterioration of sound absorption performance over time. About.

[0002]

2. Description of the Related Art FIG. 9 shows the structure of an axial flow blower 50 disposed on the ceiling for ventilation in a tunnel. The structure of a cylindrical sound deadening casing 51 and a support member 52 inside the sound deadening casing 51 are shown in FIG. And its output shaft has an impeller 5
3 is disposed in the muffler casing 51 via another support member 55-58, and the motor 54
And the inner trunks 59 and 60 provided in front of the impeller 53 and in front of the impeller 53, respectively. The muffling casing 51 includes an inner cylinder 61 made of punched metal, an outer cylinder 62 disposed with a gap, and a glass wool 63 filled in a gap between the inner cylinder 61 and the outer cylinder 62. The structure was such that the noise accompanying the rotation of the car 53 was absorbed. The inner trunks 59 and 60 also have a structure in which punched metal is provided on the ventilation surface and glass wool is provided on the inner side. In FIG. 9, reference numerals 64 and 65 indicate suspension rings.

[0003]

However, the axial blower 50 according to the conventional example described above has the following problems. 1) Since the axial blower in the tunnel is exposed to exhaust gas, dust, humid outside air, scattering of deicing agent and sea breeze, etc., the glass wool 6 filled between the inner cylinder 61 and the outer cylinder 62 is exposed.
No. 3 absorbs these and the sound absorbing performance is reduced. In particular, the glass wool 63 is extremely easy to absorb moisture,
When moisture is absorbed, the sound absorbing performance temporarily decreases. 2) If the axial blower 50 is contaminated, it is extremely difficult to clean the inside of the tunnel, and if necessary, the axial blower 5
It is necessary to remove the 0 once and disassemble and maintain it, which is extremely troublesome. The present invention has been made in view of such circumstances,
It is an object of the present invention to provide an axial blower suitable for ventilation in a tunnel, which suppresses deterioration of noise reduction performance due to aging.

[0004]

According to the present invention, there is provided an axial-flow blower according to the present invention, comprising: a tubular silencing casing; and an electric motor arranged at the center of the silencing casing.
In the axial blower having an impeller provided on the output shaft, the muffling casing is in contact with an inner cylinder formed of a perforated plate having a number of small holes formed at predetermined intervals, and an outer side of the inner cylinder. It has a thin plate-shaped porous sound absorbing material arranged in a state, and an outer cylinder arranged with a gap outside the porous sound absorbing material. Here, an inner body may be provided behind the electric motor and in front of the impeller, whereby the flow of airflow generated by the impeller can be adjusted by the inner body. Further, the inner body is a streamlined outer plate composed of a perforated plate having a number of small holes formed at predetermined intervals, a porous sound absorbing material disposed in close contact with the inside of the outer plate, 30 to 120 mm (more preferably 30 to 100 mm)
mm) and an inner plate formed with a gap of (mm).

Further, in the present invention, noise can be reduced more effectively by providing a honeycomb body having a radially formed through hole between the porous sound absorbing material and the outer cylinder. Further, in the present invention, the porous sound-absorbing material is made of a plate having a thickness of 1 to 5 mm obtained by solidifying aluminum powder, aluminum fiber, or ceramic powder, and the perforated plate has an aperture ratio of the small holes of 30 to 50%. It is more preferable that the gap between the porous sound-absorbing material and the outer cylinder is in the range of 30 to 120 mm, which further promotes the improvement of the noise reduction effect.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a cross-sectional view of an axial blower according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of an inner trunk of the coaxial blower, FIG. 4 is a sectional view taken along the line BB in FIG. 1, FIG. 5 is a graph showing a relationship between a noise level and a frequency band when a coaxial blower is used, and FIG. 6 is a 1/3 octave band center frequency and a reverberation chamber method. FIG. 7 is a graph showing a relationship between sound absorption coefficients, FIG. 7 is a sectional view of an axial blower according to another embodiment of the present invention, and FIG. 8 is a sectional view taken along the line CC in FIG.

As shown in FIGS. 1 to 4, an axial blower 10 according to an embodiment of the present invention has a cylindrical noise reduction casing 11 and a noise reduction casing 11, the axial center of which is arranged at the center of the noise reduction casing 11. It has an electric motor 12 and an impeller 13 provided on its output shaft, and inner shells 14 and 15 provided behind the electric motor 12 and in front of the impeller 13, respectively. Less than,
These will be described in detail.

As shown in FIG. 1, the muffling casing 11 has a three-part structure of flange connection, as shown in FIG.
As shown in detail in FIG. 1, an aluminum sintered plate 1 which is an example of a thin porous sound absorbing material provided concentrically with an inner cylinder 16 and an outer cylinder 17 and provided outside the inner cylinder 16 in a joined state.
8 and a honeycomb body 19 provided between the aluminum sintered plate 18 and the outer cylinder 17. The inner cylinder 16 is made of a stainless steel plate having a thickness of 3 to 6 mm. For example, the inner cylinder 16 is made of a punching metal (an example of a perforated plate) in which a large number of small holes 20 having a diameter of about 12 mm are formed at an opening ratio of 40%. ing. The aluminum sintered plate 18 having a thickness of, for example, 1.6 mm provided on the outer side of the inner cylinder 16 is manufactured by sintering aluminum powder into a plate shape, and can be bent, and has ventilation. It has the characteristic of having sound absorbing properties. Further, since the aluminum sintered plate 18 has poor water retention and is excellent in quick-drying property and does not retain moisture therein for a long period of time, even if moisture or the like is attached due to the operation of the axial blower, it is dried in a short period of time. , The adsorption capacity recovers early. In addition, since there is no material deterioration and no clogging, the adsorption capacity can be maintained permanently.

The honeycomb body 19 is formed by processing a resin or aluminum plate into a honeycomb shape, and has a height of approximately 50 to 120 mm in accordance with a gap between the aluminum sintered plate 18 and the outer cylinder 17. . The honeycomb body 19 has sufficient strength in the radial direction with the through holes 21 being directed in the radial direction. Outside the honeycomb body 19, the outer cylinder 1
7 are provided. This outer cylinder 17 has a thickness of about 1.6 m.
It is made of a steel plate of about m and plays a role as a reflection plate. Therefore, although the noise propagating in the radial direction through the aluminum sintered plate 18 and the honeycomb body 19 is reflected by the outer cylinder 17, the aluminum sintered plate 18 is provided and the thickness of the honeycomb body 19 is properly adjusted (about 50 mm in FIG. 1). )
By setting to, the silencing property against the diffuse incident wave is improved.

As shown in FIGS. 1 and 4, a plurality of suspension rings 22 and 23
The axial blower 10 can be suspended by a support member (not shown) in the tunnel. The electric motor 12 is provided inside the muffling casing 11 through a plurality of support members 24 so as to be aligned with the muffling casing 11. This electric motor 1
The second terminal box 25 is disposed outside the sound deadening casing 11 as shown in FIG. The impeller 13 is attached to an output shaft of the electric motor 12, and is driven to rotate by the electric motor 12. In FIG. 4, 2
Reference numeral 5a denotes a flange provided at the end of the divided sound deadening casing 11, and the flange 25a is provided with a number of bolt holes 25b.

On the other hand, in the rear of the electric motor 12 and in front of the impeller 13, inner shells 14, 15 are provided, respectively.
As shown in FIGS. 1 and 3, the inner trunks 14 and 15 are attached to the sound deadening casing 11 via a support member 26, and regulate the flow of airflow generated by the impeller 13.
The inner shells 14 and 15 are provided with outer plates 27 and 28 whose front ends are reduced in diameter to form streamlines. This outer plate 28
(Similarly, 27) has a large number of small holes 28a as shown in FIG.
Is made of punched metal (perforated plate) having an aperture ratio of 40% and formed at a predetermined interval, and an aluminum sintered plate 29 having the same configuration as the aluminum sintered plate 18 is adhered to the inside thereof. I have. The inner plate 30 is spaced from the aluminum sintered plate 29 by a distance of 30 to 120 mm.
Is provided. In FIG. 2, reference numeral 30a denotes a plastic spacer. Since the inner trunks 14 and 15 are configured as described above, the flow of the airflow generated by the impeller 13 is adjusted, and when the noise generated by the rotation of the impeller 13 enters the interior, the noise is silenced. This has the effect of reducing transmitted noise.

FIG. 5 shows the measurement results of the noise characteristics on the suction port 31 side of the axial flow blower 10 according to the embodiment when the length of the honeycomb body 19 in the radial direction is approximately 100 mm. The noise value of the frequency and all the noise values p shown at the right end of the graph were the same as those of the conventional axial blower using glass wool. Further, even if the axial blower 10 itself is covered with water, there is no water retention unlike the conventional axial blower in which glass wool is applied, so that the noise level does not increase. The broken line in FIG.
The relationship between the reverberation room method sound absorption coefficient and the 周波 数 octave band center frequency is shown.
It can be seen that the sound absorption coefficient is high in the portion from z to 4 kHz.

In the axial blower 10 according to the embodiment, as shown in FIG. 1 (B), the honeycomb body in the sound deadening casing 11 may be omitted and the inside may be hollow. In this case, the sound that has passed through the inner cylinder 16 is absorbed by the aluminum sintered plate 18, and furthermore, the space 3 formed by the gap between the aluminum sintered plate 18 and the outer cylinder 17.
2, it collides with the outer cylinder 17, but is reflected inside the outer cylinder 17 and is adsorbed again by the aluminum sintered plate 18. Sound is attenuated by sound absorption due to frictional resistance as a porous material, a resonance sound absorption mechanism composed of the porous material, the gap, and the outer cylinder 17, and a resonance sound absorption mechanism composed of the inner cylinder 16, the gap, and the outer cylinder 17.

The solid line in FIG. 6 has a space 32 formed by the aluminum sintered plate 18 and the outer cylinder 17, and the space 32 has a radial length of 100 mm according to another embodiment. The relation of the reverberation room method sound absorption coefficient to the 1/3 octave band center frequency of the blower is shown. Compared with the axial blower 10 using the honeycomb body 19 (dashed line in FIG. 6), the sound absorption coefficient is slightly reduced except for a specific range, and it can be sufficiently used as an axial blower for a tunnel road, and can be manufactured at a low cost. is there. Note that support members are provided in the space 32 at an appropriate pitch so that the distance between the inner cylinder 16 and the outer cylinder 17 is properly maintained. In the axial flow blower 10 of the embodiment, the inner shells 14 and 15 are provided behind the electric motor 12 and in front of the impeller 13, respectively, but depending on the situation, as shown in FIGS. In some cases, the axial blower 10a of another embodiment does not include an inner trunk. FIG.
FIG. 8 is a sectional view taken along the line CC in FIG. 7. 7 and 8, the same components as those of the axial blower 10 are denoted by the same reference numerals, and similar components are denoted by the same reference numerals and the description thereof is omitted. As shown in the figure, the support member 26 a has a semicircular cover 33 in front of the center of the impeller 13, and a cover 34 is also attached to the rear of the motor 12. In the above embodiment, the inner shells 14 and 15 are
Although the structure is the same as that described above, the present invention is not limited to this, and another structure may be used. Further, although an aluminum sintered plate in which aluminum powder is solidified is used as the porous sound absorbing material, a plate in which aluminum fiber or ceramic powder is solidified may be used.

[0015]

In the axial blower according to any one of the first to fifth aspects, the muffling casing is in a state of being in contact with an inner cylinder formed of a perforated plate having a number of small holes formed at predetermined intervals and an outer side of the inner cylinder. Since it has a thin plate-shaped porous sound absorbing material arranged in the above, and an outer cylinder arranged with a gap outside the porous sound absorbing material, sound can be absorbed by the porous sound absorbing material, and the inner cylinder or porous A resonance sound absorbing mechanism consisting of a sound absorbing material, a gap and an outer cylinder is formed,
The silencing effect increases. Therefore, even if there is moisture absorption due to use, the decrease in sound absorbing performance is temporary, and returns to the original sound absorbing performance with drying of the porous sound absorbing material. In addition, there is almost no aging deterioration. In the axial flow blower according to the third aspect, the inner body is disposed in close contact with a streamlined outer plate formed of a perforated plate having a number of small holes formed at predetermined intervals, and the inside of the outer plate. Since it has a porous sound-absorbing material and an inner plate formed with a gap of 30 to 120 mm inside thereof, the sound-absorbing effect can be efficiently exhibited even in the inner trunk portion, and the axial-flow fan The overall noise can be reduced. In the axial flow blower according to the fourth aspect, since the honeycomb body having the through hole formed in the radial direction is provided between the porous sound absorbing material and the outer cylinder, noise passing through the honeycomb body is separated and attenuated. As a result, the silencing property can be improved. And Claim 5
In the axial blower described above, the porous sound-absorbing material is made of a plate having a thickness of 1 to 5 mm obtained by solidifying aluminum powder, aluminum fiber, or ceramic powder, and a perforated plate is formed by punching with a small hole having an opening ratio of 30 to 50%. Since it is made of metal, it has excellent quick-drying properties and dries quickly even if it absorbs moisture, thereby providing an axial blower having a longer service life.

[Brief description of the drawings]

FIG. 1 is a sectional view of an axial blower according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of an inner trunk of the coaxial blower.

FIG. 3 is a sectional view taken along the line AA in FIG.

FIG. 4 is a sectional view taken along the line BB in FIG. 1;

FIG. 5 is a graph showing a relationship between a noise level and a frequency band when a coaxial blower is used.

FIG. 6 is a graph showing a relationship between a 1/3 octave band center frequency and a reverberation room sound absorption coefficient.

FIG. 7 is a cross-sectional view of an axial blower according to another embodiment of the present invention.

8 is a sectional view taken along the line CC in FIG. 7;

FIG. 9 is a sectional view of an axial blower according to a conventional example.

[Explanation of symbols]

10: axial blower, 10a: axial blower, 11: silencing casing, 11a: silencing casing, 12: electric motor, 1
3: impeller, 14: inner body, 15: inner body, 16: inner cylinder, 1
6a: inner cylinder, 17: outer cylinder, 17a: outer cylinder, 18: aluminum sintered plate (porous sound absorbing material), 19: honeycomb body, 2
0: small hole, 21: through hole, 22: suspension ring, 23: suspension ring,
24: support member, 25: terminal box, 25a: flange, 25b: bolt hole, 26: support member, 26a: support member, 27: outer plate, 28: outer plate, 28a: small hole, 2
9: aluminum sintered plate, 30: inner plate, 30a: spacer, 31: suction port, 32: space, 33: cover, 34: cover

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazumi Wada 2-2 Nitetsu Hachiman Engineering Co., Ltd., Tobata-ku, Kitakyushu-city, Fukuoka Prefecture (72) Inventor Yutaka Arita 2-28 Asahimachi, Omuta-shi, Fukuoka Prefecture address

Claims (5)

[Claims] 1. An axial blower having a cylindrical silencing casing, an electric motor arranged at the center of the silencing casing in an axial center, and an impeller provided on an output shaft thereof, wherein the silencing casing is An inner cylinder made of a perforated plate having a number of small holes formed at predetermined intervals, a thin plate-shaped porous sound absorbing material arranged in contact with the outer side of the inner cylinder, and an outer side of the porous sound absorbing material. And an outer cylinder arranged with a gap in the axial flow fan. 2. The axial blower according to claim 1, wherein an inner shell is provided behind the electric motor and in front of the impeller, respectively. 3. The axial blower according to claim 2, wherein the inner shell is in close contact with a streamlined outer plate formed of a perforated plate having a number of small holes formed at predetermined intervals, and inside the outer plate. Porous sound-absorbing material and 30-120m inside
an inner plate formed with a gap of m. 4. The axial blower according to claim 1, wherein a honeycomb body having a through hole formed in a radial direction is provided between the porous sound absorbing material and the outer cylinder. An axial blower characterized by the following. 5. The axial blower according to claim 1, wherein the porous sound-absorbing material is a plate having a thickness of 1 to 5 mm obtained by solidifying aluminum powder, aluminum fiber, or ceramic powder. The perforated plate is made of a punched metal having an aperture ratio of the small holes of 30 to 50%, and a gap between the porous sound absorbing material and the outer cylinder is 30%.
An axial blower characterized by being in the range of up to 120 mm.