JP2005009377A - Sound insulation structure for blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound insulation structure for a blower especially effectively preventing generation of wind noise. <P>SOLUTION: This sound insulation structure for the blower has a sound insulating tube part 2 forming a draft passage 4 provided on a blower main body 1 generating axial flow. Sound absorbing body 3 is installed inside of the sound insulating tube part 2. The draft passage 4 is formed to force wind passing through the sound insulating tube 2 from one end side to another end side to meander along an axis direction of the sound insulating tube part 2 in such a manner that the wind can not flow straightly, and total section area of the draft passage 4 at both end sides of the sound insulating tube part 2 is formed larger than total section area of the draft passage 4 at an axis direction center part of the sound insulating tube part 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soundproof structure for a blower in which a soundproof cylinder portion that forms a blower flow path is provided in a blower main body that generates an axial flow, and a blower silencer.
In order to ventilate ventilation target parts such as tunnels and underpasses, such a blower drives the blower main body to take in outside air from the intake side and supply air from the exhaust side to the ventilation target part. . This type of blower often has to generate a large flow of air at a high speed and is likely to generate a great deal of noise. In addition, the ventilation target portion often needs to be constantly ventilated over a long period of time due to construction or the like, and such noise may be a great nuisance to the construction worker or nearby residents.
[0002]
[Prior art]
Conventionally, in order to prevent such a blower from sounding, the bottomed cylinder in which the soundproofing cylinder part 2 is provided with an inner cylinder part 21d inside the outer cylinder part 21a and the inner cylinder part 21d is opened to the fan body 1 side. What is called a “splitter type” is known and widely used (see FIG. 8), in which the air flow path 4 is formed between the inner cylinder part 21d and the outer cylinder part 21a.
In addition, a technique has been put into practical use in which a sound absorbing body is interposed in the soundproofing cylinder portion so that noise generated from the blower body is absorbed and noise is not leaked to the surroundings.
When a sound absorbing body is interposed in the soundproof cylinder portion, a large number of the sound absorbers are usually arranged in parallel along the flow direction of the airflow inside the cylindrical soundproof cylinder portion. With this arrangement, it is expected that the soundproofing effect can be enhanced while generating the airflow without increasing the airflow resistance.
However, in order to further improve the sound absorption performance with such a sound absorber, it is necessary to use a larger sound absorber, but there is a limit to the increase in the size of the sound absorber.
Furthermore, as another soundproof structure for improving the sound absorption performance, a cylindrical sound absorber is arranged orthogonal to the airflow passage direction, and the cross-sectional area of the air flow passage in the soundproof cylinder portion is passed through the airflow. The thing changing along a direction is considered (refer patent document 1).
[0003]
[Patent Document 1]
JP-A-7-42890 [0004]
[Problems to be solved by the invention]
When such a soundproof structure is applied to a blower, noise in a wide frequency range can be absorbed. However, even in such a case, wind noise is prominently generated near the entrance and exit of the soundproof cylinder. As described above, there is a case where noise that cannot necessarily be generated in the soundproof cylinder portion cannot be effectively absorbed. In such a case, even if the cross-sectional area of the air flow path in the soundproofing cylinder part is changed along the passage direction of the airflow, the airflow path is configured so that the wind can travel straight in the axial direction of the soundproofing cylinder part. If formed, there is a sound that permeates along the straight air flow path, and it is considered that sufficient soundproof performance cannot be exhibited. Further, if the total cross-sectional area of the air flow path on the end side of the soundproof cylinder part is smaller than the total cross-sectional area of the airflow path in the axial center of the soundproof cylinder part, the inside of the soundproof cylinder part is The speed of the advancing wind is locally increased on the end side of the soundproofing cylinder portion, which causes a situation where wind noise is more likely to occur.
[0005]
Accordingly, an object of the present invention is to provide a soundproof structure in which the soundproof performance of the blower is further improved in view of the above-mentioned drawbacks.
[0006]
[Means for Solving the Problems]
In order to achieve this object, the characteristic structure of the soundproof structure of the blower of the present invention is:
In the blower body that generates the axial flow, a soundproof cylinder portion that forms a blower flow path is provided,
A sound absorbing body is provided in the soundproofing cylinder part, and an air flow path is formed that causes the wind passing from one end side to the other end side of the soundproofing cylinder part to meander in a straight line along the axial direction of the soundproofing cylinder part. ,
The total cross-sectional area of the air flow path at both ends of the soundproof cylinder is larger than the total cross-sectional area of the airflow path at the central portion in the axial center direction of the soundproof cylinder.
[0007]
As a result, the wind entering the soundproofing cylinder part passes through the soundproofing cylinder part while meandering in the soundproofing cylinder part. For this reason, even if a wind noise is generated along the wind, the sound travels straight, so that it always collides with the sound absorber, and high soundproof performance can be exhibited.
Further, since the total cross-sectional area of the air flow path in the central portion in the axial center direction of the soundproofing cylinder portion is smaller than both end sides, the flow velocity of the wind is fastest in the central portion. Therefore, the wind noise generation position is mainly in the center of the soundproof cylinder. Therefore, the generated noise collides with the sound absorber and is easily absorbed. Therefore, the wind noise can be effectively prevented from being transmitted as noise to the outside of the blower.
[0008]
In addition to the above configuration, it is preferable that the width of the sound absorbing body in the front view of the soundproofing cylinder is wider than the width of the air flow path formed between the sound absorbing bodies.
[0009]
If comprised in this way, the direction of the wind which passes between the said sound absorbers can be completely interrupted | blocked with the downstream sound absorber. That is, the air flow path through which the wind goes straight is not formed, and the air flows to the downstream side while meandering with certainty. As a result, even if wind noise is generated during meandering, the wind noise collides with the sound absorber along the flow of the wind, and noise is efficiently absorbed.
[0010]
Furthermore, it is preferable that the sound absorbing body is configured by sandwiching a fibrous sound absorbing material between a pair of perforated plates.
[0011]
According to this configuration, for example, the porous plate securely holds a sound absorbing material such as glass wool or rock wool, and is installed in the soundproofing cylinder, and guides sound to the sound absorbing material through the hole of the porous plate. This is advantageous in forming a soundproof structure.
[0012]
Furthermore, it is preferable that the sound-absorbing-body-side tip portion of the sound absorbing body in a cross-sectional plan view of the soundproof cylinder portion is provided to be inclined with respect to the air flow path.
[0013]
The sound generated directly from the blower main body goes straight and enters the soundproof cylinder. The sound that collided with the tip part may be reflected to the blower body side and resonate with the sound from the blower body. If it is provided with an inclination, the sound that collides with the tip portion is skewed while being reflected. Therefore, it is difficult to resonate with the sound from the blower main body, and depending on the inclination angle, the reflected sound can be effectively collided with the sound absorber, so that the noise absorption effect can be enhanced.
[0014]
Furthermore, it is preferable that the inner diameter at the central portion in the axial center direction of the soundproof cylinder portion is smaller than the inner diameter at both end portions.
[0015]
With this configuration, the total cross-sectional area of the air flow path at both ends of the soundproofing cylinder part is formed larger than the total cross-sectional area of the airflow path in the axially central part of the soundproofing cylinder part. It is done. For this reason, the said soundproof structure can be formed simply by arrange | positioning the sound-absorbing body of a predetermined shape regularly.
[0016]
The soundproofing cylinder portion is formed in a rectangular tube shape, and a large number of the plate-shaped sound absorbers are provided in the soundproofing cylinder portion, and the soundproofing cylinder portion is erected in a posture along the axial direction of the soundproofing cylinder portion. In forming the structure, since the sound absorbing body is flat, it is easy to handle and easy to position, and it is easy to form an air flow passage surrounded by the sound insulating body in the axial direction of the soundproofing cylinder portion.
[0017]
The soundproofing cylinder part is formed in a cylindrical shape, the cylindrical sound absorbing body is housed in the soundproofing cylinder part, and the axial center thereof is arranged along the axial center of the soundproofing cylinder part. The noise inside the soundproof cylinder is configured so that it can be absorbed by the sound absorber even if it diverges in any direction, and since the side surface of the sound absorber is cylindrical, it has less directivity than a flat plate. . Therefore, it is possible to prevent the direction of noise from occurring.
[0018]
Provided with a pair of soundproof cylinders and a blower accommodating part that can accommodate a blower main body, allowing a wind to flow from one of the soundproof cylinders to the other soundproof cylinder via the blower main body, If configured,
A sound absorbing body is provided in the soundproofing cylinder part, and an air flow path is formed that causes the wind passing from one end side to the other end side of the soundproofing cylinder part to meander in a straight line along the axial direction of the soundproofing cylinder part. ,
It is preferable that the total cross-sectional area of the air flow path at both ends of the soundproofing cylinder part is formed larger than the total cross-sectional area of the airflow path at the central part in the axial center direction of the soundproofing cylinder part.
[0019]
According to such a configuration, it is possible to easily realize the above-described soundproof structure of the blower simply by attaching the blower main body used conventionally or the blower main body having a different air flow rate to the blower silencer. As a result, it has become possible to easily cope with improving the performance of the blower.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 and 2, the soundproof structure of a blower of the present invention is applied to a blower called a contrafan used for blowing and ventilating a tunnel or the like, for example.
[0021]
(1) The blower is provided with, for example, a blower main body 1 that generates an axial flow, a duct-shaped cover 11 that surrounds the blower main body 1, and sucks air from one side 11a of the duct-shaped cover 11, while the other It is configured to supply air to the side 11b. A pair of soundproof cylinders 2 are provided on both ends of the body 12 of the blower body 1 via a seismic duct 18, and a blower channel 4 extending the wind channel formed by the duct-shaped cover is provided. Form. The blower main body 1 includes a motor 14 that rotationally drives the impeller 13, and is fixed to a pedestal 17 via an anti-vibration rubber 15 and a support frame 16. With such a configuration, the vibration caused by vibrations of the motor 14, the impeller 13, etc. is prevented from being propagated to the outside.
[0022]
As shown in FIGS. 2 and 3, in the soundproof cylinder portion 2, a large number of sound absorbers 3 are erected inside a rectangular tubular casing 21 that is fixed on the base 17. Decorated.
[0023]
As shown in FIG. 4, the sound absorber 3 includes a fibrous sound absorbing material 32 made of rock wool, for example, between a pair of perforated plates 31 and 31 having an aperture ratio of about 60%. Both end portions of the sound absorber 3 in a cross-sectional plan view of the soundproof cylinder portion 2, that is, a tip portion on the blower body 1 side and a tip portion on the side away from the blower body 1 are inclined with respect to the blower flow path 4. It is formed on the protruding edge 33. If the portion directly receiving the wind of the projecting edge portion 33 is formed of a perforated plate, the sound absorbing material 32 is likely to be scattered and reduced, and the sound absorbing effect may be reduced. For this reason, while the said projecting edge part 33 comprises the ventilation direction upstream from the metal plate, the ventilation direction downstream is comprised from the perforated plate.
[0024]
The tip angle of the projecting edge 33 is 60 °. Thus, the wind can be easily guided to the air flow path 4 and the sound incident from the front can be easily reflected to the side so as to collide with the adjacent sound absorber 3. The sharper the tip angle, the more advantageous in terms of ventilation resistance. However, the sharper the tip angle, the thinner the tip of the sound absorber, and the greater the area where the sound absorbing material cannot be filled. It is not preferable to form it. Therefore, it is preferable to set the tip angle to about 40 ° to 90 ° in order to prevent scattering of the sound absorbing material and to ensure a large area in the sound absorbing body that can be filled with the inner sound absorbing material.
In addition, the tip is sharply sharpened. However, it is possible to form the tip with the above-mentioned tip angle while being rounded. It may be possible to suppress the noise and enhance the noise reduction effect.
[0025]
Also, the aperture ratio of the porous plate is preferably 70% or less from the viewpoint of holding stability of the filler, and preferably 30% or more from the viewpoint of sound permeability to the sound absorbing material.
[0026]
The casing 21 is a cylindrical body in which a sound absorbing material 21c is sandwiched between an outer cylindrical portion 21a made of a metal plate and an inner cylindrical portion 21b made of a perforated plate, and the casing 21 itself is also in the inner space. It functions as a sound absorber. The casing 21 is assembled so that the upper surface 22 can be opened freely. The sound absorber 3 is inserted into the casing 21 from the upper surface 22 side, and is fixed to the fixing portion 25 formed on the inner cylinder portion. Positioning is performed, a fixing member 26 is attached and fixed from the upper surface 22 side, the opening of the upper surface is closed, and the soundproof cylinder portion 2 is formed so as to be assembled.
[0027]
In the casing 21, the sound absorber 3 causes the wind passage 4 to meander the wind passing from one end side to the other end side of the soundproof cylinder portion 2 so as not to advance straight along the axial direction of the soundproof cylinder portion 2. And the sound generated in the soundproof cylinder 2 can be absorbed by the sound absorbing material 32 of the sound absorber 3. Specifically, the width (200 mm) of the sound absorber 3 in the front view of the soundproof cylinder 2 is wider than the width (150 mm) of the air flow path 4 formed between the sound absorbers 3 and 3. The air flow path 4 is provided meandering by arranging the sound absorbers 3 and 3 in a staggered manner, and the wind meanders along the axial direction of the soundproof cylinder portion 2 and passes therethrough.
[0028]
The inner diameter of the soundproof cylinder portion 2 in the axial center is smaller than the inner diameter of both ends, and the total cross-sectional area of the air flow path 4 on both ends of the soundproof cylinder portion 2 is the soundproof cylinder portion 2. It is formed larger than the total cross-sectional area of the air flow path 4 in the central part in the axial direction.
That is, the casing 21 is provided with a bulging portion 23 that forms the central portion with a narrow width, and the number of sound absorbing bodies 3 corresponding to the inner diameter of the casing 21 is provided so that the space between the sound absorbing bodies 3 is increased. The total cross-sectional area of the air flow path 4 formed between the casing 21 and the sound absorber 3 is set so as to approximate the ratio of the number of the sound absorbers 3.
[0029]
In addition, a speaker 51 is provided at the inlet end of the soundproofing cylinder portion 2 and a microphone 52 is provided at the inlet end of the intake side. It is also possible to provide an ANC (active noise control) system 5 that generates and cancels noise.
[0030]
In the above configuration, the blower main body provided in the blower is configured to be detachable (when the blower main body is detached, the blower main body includes a pair of soundproof cylinders and can accommodate the blower main body. It is possible to replace the blower according to the required air flow rate, or to configure the blower using the blower body of the existing blower, and to improve the performance of the blower In this case, it is possible to easily cope with the problem.
[0031]
(2) In addition, the said soundproof cylinder part 2 can be comprised cylindrically, and as shown in FIG. 5, while forming the said soundproof cylinder part 2 in a cylindrical shape, in the said soundproof cylinder part 2, it is cylindrical. The sound absorber 3 is arranged so that its axis is along the axis of the sound-insulating cylinder portion 2. As a result, the noise radiated radially around the axis of the soundproof cylinder 2 can be absorbed without directionality.
[0032]
【Example】
Examples of the soundproof structure of the blower according to the above-described embodiment (1) will be described below with reference to the drawings.
[0033]
As shown in FIG. 6, the blower is provided, two 80 KW motors are driven, and the air flow is 1500 m ³ / min. The noise at that time is A (intake side oblique 5 m), B (exhaust) When measured at the points of side oblique 5m) C (intake side lateral 1m) D (intake side oblique 1m), the frequency characteristics at each point are as shown in FIG. 7 (present inventions AD). . (AP is an evaluation for all frequencies)
[0034]
In any direction from FIG. 7, the noise level is reduced by about 20 db as compared with the noise value (conventional products A to D) measured at a position close to the fan, so the soundproof structure of the blower of the present invention is high. It was found that the soundproofing performance was demonstrated.
[0035]
In addition, the conventional splitter type soundproof structure blower (see FIG. 8) is superior in the soundproofing effect particularly in the high sound range as compared to the case where two 37KW motors are driven and the air flow is 1000 m ³ / min. It was found that it absorbs treble sounds such as wind noises particularly effectively.
[Brief description of the drawings]
FIG. 1 is a schematic view of a blower. FIG. 2 is an exploded perspective view of a soundproof cylinder. FIG. 3 is a schematic view of a soundproof cylinder. FIG. 4 is a schematic view of a sound absorber. Schematic diagram [Fig. 6] Schematic diagram showing the form of measuring the noise of the blower [Fig. 7] Frequency characteristic diagram of noise at each point [Fig. 8] Diagram of splitter type soundproof structure [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fan main body 2 Soundproof cylinder part 3 Sound absorber 4 Air flow path

Claims (8)

A soundproof structure of a blower in which a soundproof cylinder portion that forms a blower flow path is provided in a blower body that generates an axial flow,
A sound absorbing body is provided in the soundproofing cylinder part, and an air flow path is formed that causes the wind passing from one end side to the other end side of the soundproofing cylinder part to meander in a straight line along the axial direction of the soundproofing cylinder part. ,
A soundproof structure for a blower in which a total cross-sectional area of the air flow path at both ends of the soundproof cylinder is larger than a total cross-sectional area of the airflow path in the axial center of the soundproof cylinder. The soundproof structure of a blower according to claim 1, wherein a width of the sound absorbing body in a front view of the soundproofing cylinder portion is formed wider than a width of a blower passage formed between the sound absorbing bodies. The soundproof structure for a blower according to claim 1 or 2, wherein a fibrous sound absorbing material is sandwiched between a pair of perforated plates to constitute the sound absorbing body. The soundproof structure for a blower according to any one of claims 1 to 3, wherein a tip end portion on the blower main body side of the sound absorber in a cross-sectional plan view of the soundproof cylinder portion is provided to be inclined with respect to a blower flow path. The soundproof structure for a blower according to any one of claims 1 to 4, wherein an inner diameter at a central portion in the axial center direction of the soundproof cylinder portion is formed to be smaller than inner diameters at both end portions. 2. The soundproofing cylinder part is formed in a rectangular tube shape, and a large number of flat plate-like sound absorbers are provided in the soundproofing cylinder part, and are erected in a posture along the axial direction of the soundproofing cylinder part. The soundproof structure of the blower as described in any one of -5. 2. The soundproofing cylinder part is formed in a cylindrical shape, and the cylindrical sound absorbing body is housed in the soundproofing cylinder part, and its axial center is arranged along the axis of the soundproofing cylinder part. The soundproof structure of the blower as described in any one of -5. A blower silencer comprising a pair of soundproof cylinders and a blower housing that can accommodate a blower main body so that air can flow from one of the soundproof cylinders to the other soundproof cylinder via the blower main body. Because
A sound absorbing body is provided in the soundproofing cylinder part, and an air flow path is formed that causes the wind passing from one end side to the other end side of the soundproofing cylinder part to meander in a straight line along the axial direction of the soundproofing cylinder part. ,
The blower silencer in which the total cross-sectional area of the air flow path at both ends of the soundproof cylinder is larger than the total cross-sectional area of the airflow path at the axially central portion of the soundproof cylinder.

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