JP2000111111A - Hood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high sound absorbing performance with a simple structure without increasing in size by providing a sound absorbing material at an inside of a cover, and providing a sound absorbing means having a sound insulation plate for reflecting a sound in a hood and the material for absorbing the sound in combination oppositely directly to a duct. SOLUTION: The hood 1 comprises a duct 2 having a vent port 2a, a flange 2c connected to the port 2a, and a cover 1b mounted at the flange 2c to cover the port 2a and opened at its lower part. In this case, a foamed urethane sound absorbing material 4a having a thickness of about 40 mm is adhered to an inside of the cover 1b. A sound insulation plate 3 is installed oppositely directly to forward of the port 2a, and a sound absorbing material 5b having a thickness of about 10 mm is adhered to the duct 2 side. Air ducts 7 for generating an air flow can be formed between the plate 3 and the cover 1b and between the plate 3 and the port 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hood having a sound absorbing function and installed at a ventilation opening such as an outer wall of a building.

[0002]

2. Description of the Related Art FIG.
It is sectional drawing which shows the conventional exhaust device shown by -347707. In the figure, 6 is a blower fan, 1b is a cover, which forms the outer shell of the hood 1. In the hood 1, there is formed an air passage 7 which is formed by bending as a blowing passage.

[0003] The conventional hood is configured as described above. For example, the sound generated from the blower fan 6 passes through an air passage 7 formed by bending the inside of the hood 1, and the air passage 7 is configured as an expansion chamber. Therefore, it has a structure to reduce noise.

FIG. 14 shows a conventional example 2 in which a hood having a soundproof effect is formed by another method. In the figure, reference numeral 1b denotes a cover, which forms the outer shell of the hood 1. A sound absorbing material 4a is attached to the inside of the cover 1b.

[0005] By forming the hood 1 as described above, the sound emitted from the duct 2 is absorbed and attenuated by the sound absorbing material 4a attached to the inside of the cover 1b.

[0006]

SUMMARY OF THE INVENTION Conventional example 1 as described above
In the above device, since the air path is bent in the hood, the shape in the hood is complicated, and at the same time, the length of the air path formed in the hood is increased, and the entire hood is enlarged. That is inevitable. In addition, there is a problem that the size of the hood is further increased because the air passage is formed in an expansion chamber shape.

[0007] The soundproofing effect of the device of the prior art 2 is affected by the area of the sound absorbing material attached thereto.
Since the sound absorbing material cannot be adhered to more than the inner area of the cover, there is a limit in obtaining a high sound absorbing effect. Also,
The sound emitted from the ventilation hole is absorbed by the sound absorbing material inside the cover, but there is a problem that the sound that cannot be absorbed there is directly emitted to the outside.

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a hood having a simple structure and high sound absorbing performance. It is intended to be able to form without forming.

[0009]

According to the present invention, there is provided a duct having a ventilation port, and a cover which is enclosed and opened downward so as to cover the ventilation port at one end of the duct, and the inside of the cover is formed as an air passage. In the hood, a sound absorbing material is provided inside the cover, and sound absorbing means is provided in which a sound insulating plate that reflects sound and a sound absorbing material that absorbs sound are combined in the hood so as to face the duct.

Further, the sound absorbing means has an opening whose upper and lower sides or left and right sides are air paths, and is formed so as to surround the periphery of the ventilation opening of the duct.

Further, in a hood having a duct having an air vent and a cover which is open so as to cover the air vent at one end of the duct and which is opened downward, wherein the inside of the cover is formed as an air passage, And a sound absorbing means combining a sound insulating plate for reflecting sound and a sound absorbing material for absorbing sound in a hood so as to face the duct in a curved shape.

In addition, the position of the upper end of the sound absorbing means is
The duct is provided below the upper end of the ventilation port.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the hood, and FIG. 2 is a bottom view thereof. FIG.
FIG. 4 is a diagram showing sound reflection when the sound absorbing means is provided, and FIG. 4 is a diagram showing sound reflection when no sound absorbing means is provided. In the drawing, a hood 1 is attached to a wall 8 of a building, is connected to a duct pipe, and has a cylindrical duct 2 having an air vent 2c for ventilation, and a flange provided at one end of the duct 2 to be connected to the air vent. 2c and a cover 1 attached to the flange 2c so as to cover the ventilation port 2c and opened downward.
b, a 40-mm-thick urethane foam sound-absorbing material (hereinafter referred to as a sound-absorbing material) 4a is attached to the inside of the cover 1b. A sound insulating plate 3 is installed in the hood 1 as a sound absorbing means so as to face the front of the ventilation port 2c of the duct 2 and a 10 mm thick sound absorbing material 4 is provided on the duct 2 side of the sound insulating plate 3.
b is affixed. Also, between the sound insulating plate 3 and the cover 1b before and after the sound insulating plate 3, and between the sound insulating plate 3 and the vent 2a.
An air passage 7 through which an air flow can flow is formed between the air passage 7 and the air passage 7.

As described above, when the hood 1 is constituted by the cover 1b and the sound insulating plate 3, considering the path of a sound such as a blower propagating from the duct 2 to the outside, the sound is radiated at the ventilation port 2a. It is released, but the sound insulation plate 3
And is transmitted while being absorbed by the sound absorbing material 4b attached thereto. The transmitted sound is reflected by the sound insulating plate 3 and transmitted again while being absorbed by the sound absorbing material 4b. Also, cover 1
The sound transmitted to the b side also serves as a sound insulating plate where the cover 1b reflects the sound, so that the sound absorbing material 4a repeats the sound absorption while repeating the reflection between the cover 1b and the sound insulating plate 3, so that a normal hood is used. It exhibits a higher sound absorbing effect compared to a structure in which a sound absorbing material is simply attached to the. Like the sound X of the sound reflection shown in FIG. 3, the sound absorbing structure in which the sound is absorbed by the sound absorbing materials 4a and 4b while repeating the reflection between the cover 1b and the sound insulating plate 3 causes the sound to propagate from the duct 2 to the outside. In both cases, the sound absorbing structure is similarly established when the sound propagates to the duct 2 from the outside, and the same effect can be obtained. As shown in FIG. 4, when the sound insulating plate 3 of FIG. 3 is not provided, the number of times of sound reflection does not increase.

As shown in FIGS. 1 and 2, the sound absorbing material 4b affixed to the sound insulating plate 3 is affixed to the surface of the duct facing the vent 2a, and directly absorbs the sound radiated from the duct 2. When the sound absorbing material 4b is attached to the front and back sides of the sound insulating plate 3,
For the sound transmitted to the cover 1b side, the sound absorbing material 4a stuck to the cover 1b and the sound absorbing material 4 stuck to the back side of the sound insulating plate 3
b will exert a double sound-absorbing effect.
A higher effect can be obtained than when the sound absorbing material 4b is attached to only one side of the sound insulating plate 3.

The sound absorbing materials 4b and 4a to be attached are those having a thickness of 10 mm and a thickness of 40 mm. The characteristics of the sound absorbing material depend on the thickness. There is a tendency that the attenuation effect is high widely from a sound to a sound in a low frequency band, and a frequency band having a high attenuation effect is limited to a high frequency portion as the thickness becomes thinner. In the case of the sound absorbing material having a thickness of 40 mm used this time, the damping effect is high with respect to a sound in a frequency band of 500 Hz or more, which is a reference when measuring the sound absorbing effect. The sound absorbing material having a thickness of 10 mm has a high damping effect on sounds in high frequency bands that are worrisome to humans. There is an advantage that it can be widely secured. In the present embodiment, the 10 mm sound absorbing material 4 b attached to the sound insulating plate 3 first attenuates the sound center in a high frequency band of interest, and the 40 mm sound absorbing material 4 a attached to the cover 1 b provides a wider range. Although the sound in the frequency band is attenuated, the sound absorbing material 4b of 40 mm is attached to the sound insulating plate 3 to attenuate the sound of a wide frequency band, and then the sound absorbing material 4a having a thickness of 10 mm is attached to the cover 1b. Even if the configuration is affixed and replaced with a configuration that further attenuates high frequency band sounds of interest, the sound attenuation effect is high.

Further, the frequency of the sound radiated from the duct 2, the frequency band of a specific sound for which a more damping effect is desired,
It goes without saying that the thickness of the used sound absorbing material may be variously determined depending on the mutual balance such as the cross-sectional area of the air passage to be secured in the hood.

In the above description, a sound absorbing material made of urethane foam is considered as the sound absorbing material. However, it is also effective to use a sound absorbing material made of, for example, styrene foam or rubber as the sound absorbing material.

Embodiment 2 Embodiment 2 is shown in FIGS.
This will be described with reference to FIG. The hood 1 is the same as in the first embodiment, and a detailed description is omitted. FIG. 5 is a side view in which the sound insulating plate 3 installed in the first embodiment is formed and installed in a U-shape, and FIG. 6 is a bottom view thereof. In the figure, the sound insulating plate 3 is formed and installed in a U-shape so that both ends of the sound insulating plate 3 are in contact with the surface of the flange 2c so as to surround the front surface and the left and right surfaces of the ventilation port 2a of the duct 2. ing. A sound absorbing material 4b is adhered inside the U-shaped sound insulating plate 3, and a sound absorbing material 4a is adhered inside the cover 1b.

By forming and installing the sound insulating plate 3 in this manner, sound emitted radially from the ventilation opening 2a of the duct 2 can be controlled not only in front of the ventilation opening 2a but also in the horizontal direction. And the cover 1b realizes a sound reflecting structure, and a high sound absorbing effect can be obtained by the double structure together with the attached sound absorbing material.

The sound insulating plate 3 is installed so as to surround the front surface and the left and right surfaces of the vent 2a. A high sound absorbing effect is obtained by the sound reflection plate 3 and the sound reflecting structure of the cover 1b with respect to the upper surface, and at the same time, the direct sound is prevented from coming out of the lower surface, which is the opening of the hood 1, through the lower opening. Due to the structure, a high sound absorbing effect can be obtained.

The sound insulating plate 3 is formed in a U-shape. If the sound insulating plate 3 can surround the front and upper and lower surfaces or the front and left and right surfaces of the vent 2a, for example, the triangular shape shown in FIGS. Also in the case where the sound insulating plate 3 is formed and installed with a plurality of surfaces as in, for example, the same effect as in the case where the sound insulating plate 3 is formed in a U shape is exerted.

Embodiment 3 FIG. Embodiment 3 is shown in FIGS.
Explanation will be made using 0. The hood 1 is the same as in the first embodiment, and a detailed description is omitted. FIG. 9 is a side sectional view of this embodiment. A sound absorbing material 4a having a thickness of 40 mm is attached to the inside of the cover 1b forming the hood 1. In the hood 1, as a sound absorbing means, the sound formed on the semi-cylindrical curved surface is reflected so that both ends of the sound insulating plate 3 abut on the surface of the flange 2 c at positions directly opposite the ventilation holes 2 a of the duct 2. A sound insulating plate 3 is provided. This sound insulation plate 3 is a duct 2
And a vent 2 a of the hood 1. An air flow can flow between the sound insulating plate 3 and the cover 1b and between the sound insulating plate 3 and the vent 2a as an air path 7.
A sound absorbing material 4b having a thickness of 10 mm is attached to the sound insulating plate 3 on the duct side.

By forming and installing the sound insulating plate 3 in this manner, considering, for example, the case where the sound propagates from the duct 2, the sound is transmitted while being absorbed by the sound absorbing material 4b, reflected by the sound insulating plate 3, and again. The sound is transmitted and emitted while being absorbed by the sound absorbing material 4b. At this time, due to the curved shape of the sound insulating plate 3, the sound reflection directions are dispersed and not concentrated, so that the sound energy can be dispersed.

At the same time, the air passage 7 in the hood 1 is divided by the sound insulating plate 3, and the width between the divided air passages 7 is reduced. Therefore, the case where sound propagates from the duct 2 to the outside and the case where sound propagates from the outside to the duct 2 are the same,
The number of times the sound is reflected in the hood in the process of sound coming and going increases, and the number of times the sound hits the sound absorbing material provided in the hood increases accordingly, thereby increasing the sound absorbing effect.

Further, by forming and installing the sound insulating plate 3 in this manner, even if it is necessary to mount a component 5 such as a fireproof damper that rotates in the vicinity of the vent 2a as shown in FIG. 11, for example. Since the sound insulating plate 3 is installed so as to avoid the movable part of the component 5, the component can be attached to the hood 1 without changing the formation of the hood 1 itself, thereby realizing a highly flexible hood configuration. are doing.

Although the sound insulating plate 3 is formed by a curved surface like a semi-cylindrical shape, if the shape of the sound insulating plate 3 is, for example, a hemispherical shape having openings on the upper and lower sides or on the left and right,
Since the direction of the reflected sound is more dispersed and reflected in the vertical direction as well as the horizontal direction, the sound energy can be more dispersed. .

Embodiment 4 Embodiment 4 will be described with reference to FIG. The hood 1 is the same as in the first embodiment, and a detailed description is omitted. FIG. 12 shows the sound insulating plate 3 according to the first, second and third embodiments installed such that the upper end 3 b of the sound insulating plate 3 is located below the upper end 2 b of the ventilation port 2 a of the duct 2. A sound absorbing material 4b is adhered inside the sound insulating plate 3, and a sound absorbing material 4a is adhered inside the cover 1b.

By setting and installing the sound insulating plate 3 in this manner, the airflow flowing through the duct 2 is moved between the sound insulating plate 3 on the back side of the sound insulating plate 3 and the cover 1b, and the front side of the sound insulating plate 3 is formed. Since it can be easily separated from the flowing airflow B, the resistance of the sound insulating plate 3 to the airflow is reduced, the airflow is generated smoothly, and a hood with low pressure loss can be obtained.

[0030]

According to the present invention, a sound absorbing material is attached to the inside of a hood, and a sound insulating plate is installed in the hood so as to face a ventilation opening of a duct, and the sound absorbing material is also attached to the sound insulating plate. Accordingly, the sound of the blower and the like transmitted through the duct is attenuated by the sound absorbing material attached to the sound insulating plate in front of the duct. The attenuated sound is further attenuated by the sound-absorbing material attached to the hood at the back, thereby achieving a double sound-absorbing structure, and a high sound-absorbing effect is obtained.

Also, the sound insulation plate is formed on a plurality of surfaces such as a U-shape and installed, and is installed so as to surround the front surface and the left and right surfaces of the ventilation opening of the duct. The sound insulation plate and the hood have a double sound absorption structure not only on the front but also on the left and right sides of the vent, and a high sound absorption effect can be obtained by the sound absorbing material attached to the sound insulation plate.

Further, by forming the sound insulating plate with a curved surface such as a semi-cylindrical shape, the sound re-emission direction is dispersed and the sound reflection ratio in the hood is increased, so that a higher sound absorbing effect is obtained.

Further, by installing the upper end of the sound insulating plate so as to be positioned lower than the upper end of the ventilation port of the duct, the airflow flowing through the duct is located between the sound insulating plate and the hood on the back side of the sound insulating plate. The airflow flowing therebetween and the airflow flowing on the front side of the sound insulating plate are easily separated, and the resistance of the sound insulating plate to the airflow can be reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing Embodiment 1 of the present invention.

FIG. 2 is a bottom view showing the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of sound reflection in the first embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of sound reflection without a sound insulating plate.

FIG. 5 is a side sectional view showing Embodiment 2 of the present invention.

FIG. 6 is a bottom view showing Embodiment 2 of the present invention.

FIG. 7 is a side sectional view showing another example of the second embodiment of the present invention.

FIG. 8 is a bottom view showing another example of the second embodiment of the present invention.

FIG. 9 is a side sectional view showing Embodiment 3 of the present invention.

FIG. 10 is a bottom view showing Embodiment 3 of the present invention.

FIG. 11 is a bottom view showing Embodiment 3 of the present invention.

FIG. 12 is a side sectional view showing Embodiment 4 of the present invention.

FIG. 13 is a sectional view showing a conventional device.

FIG. 14 is a cross-sectional view showing another conventional apparatus.

[Explanation of symbols]

1 hood, 1a hood lower edge, 1b cover,
2 duct, 2a vent, 3 sound insulating plate, 3b upper end of sound insulating plate, 4a sound absorbing material, 4b sound absorbing material.

Claims (4)

[Claims] 1. A hood having a duct having an air vent, and a cover surrounding the air vent at one end of the duct and opening downward, wherein the inside of the cover is formed as an air passage. And a sound absorbing means combining a sound insulating plate for reflecting sound and a sound absorbing material for absorbing sound in the hood so as to face the duct. 2. A hood according to claim 1, wherein said sound absorbing means has an opening whose upper and lower sides or left and right sides are air paths, and is formed so as to surround a periphery of a ventilation opening of said duct. 3. A hood having a duct having an air vent, and a cover surrounding the air vent at one end of the duct and opening downward, wherein the inside of the cover is formed as an air passage. A hood, wherein a sound absorbing member comprising a sound insulating plate for reflecting sound and a sound absorbing material for absorbing sound is formed in the hood so as to face the duct so as to face the duct. 4. The hood according to claim 1, wherein the sound absorbing means is provided such that an upper end thereof is located below an upper end of a vent of the duct. .