JP4107533B2 - Sound barrier - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soundproof wall installed on a dedicated road for automobiles or a road with a large amount of traffic for automobiles.
[0002]
[Prior art]
Sound barriers using sound-absorbing panels have been installed on both sides of roads dedicated to automobiles and high-traffic roads. However, such a noise barrier is intended to suppress noise pollution caused by noise generated by the automobile, and is ineffective against air pollution caused by harmful substances in the exhaust gas generated by the automobile.
[0003]
Therefore, for several years, studies have been made to attach a photocatalyst of titanium dioxide to the surface of a soundproof wall, oxidize nitrogen oxides in exhaust gas in the presence of ultraviolet rays in sunlight, and remove it as nitric acid. However, even if a photocatalyst is attached to the entire surface of the soundproof wall, the contact time between the exhaust gas and the soundproof wall is short and the contact efficiency is not high, so the effect of removing nitrogen oxides in the exhaust gas is not sufficient. it is conceivable that.
[0004]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-described conventional problems and to provide a novel soundproof wall that has a higher effect of removing nitrogen oxides in exhaust gas than the prior art and also has a higher soundproofing effect than the prior art. .
[0005]
[Means for Solving the Problems]
The present invention has been made in order to solve the aforementioned problem, a soundproof wall arranged sound absorbing tube along the top of the sound insulating wall, the sound absorbing tube is made of aluminum fibers sound absorbing material adhered with the photocatalyst, the sound absorption The cylinder is formed to have an outer diameter larger than the thickness of the sound insulation wall, the photocatalyst is present over the surface, the inside and the inner surface, and includes a means for decompressing the inside of the sound absorbing cylinder, and inside the sound absorbing cylinder. An ultraviolet lamp is arranged. Further, a photocatalyst may be attached to the surface of the sound insulation wall. A photocatalyst such as titanium dioxide can be used as the photocatalyst.
[0006]
Sound barrier of the present invention, Ri Na from aluminum fibers sound absorbing material and the sound absorbing cylinder installed on the upper end of the sound insulating wall by adhering photocatalyst, since that was formed in greater thickness outside diameter of the sound insulation wall, exhaust the sound absorption When flowing along the surface of the cylinder, the nitrogen oxide is removed by contact with the photocatalyst. In addition, since the exhaust gas stays for a certain period of time at the connection between the flat sound insulation wall and the cylindrical sound absorption cylinder, the contact efficiency between the exhaust gas and the photocatalyst is increased, and the photocatalyst is simply attached to the flat soundproof wall as in the past. It is possible to obtain a nitrogen oxide removal effect superior to that of the above. Moreover, since this sound absorption cylinder is also excellent in noise prevention effect, it can exhibit two effects of removing nitrogen oxides in exhaust gas and preventing noise. If a means for reducing the pressure inside the sound absorbing cylinder is provided, the exhaust gas passes through the aluminum fiber sound absorbing material as a filter, so that the purification effect can be further enhanced. The exhaust gas taken into the sound absorbing cylinder can be further purified by the internal ultraviolet lamp and the inner photocatalyst.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
FIG. 1 is a sectional view of a soundproof wall according to the present invention. Reference numeral 1 denotes a conventional flat soundproof wall, and reference numeral 2 denotes a sound absorbing cylinder installed horizontally along the upper end of the soundproof wall 1. The sound insulating wall 1 may be a concrete sound insulating wall or a sound absorbing sound insulating wall provided with a sound absorbing panel. The sound absorbing cylinder 2 is obtained by processing an aluminum fiber sound absorbing material into a cylindrical shape larger than the width of the sound insulating wall 1, but it is not always necessary to have a complete cylindrical shape, and a sectional shape like a deformed cylinder as shown in FIG. It is good. An appropriate partition may be provided inside the sound absorbing cylinder 2. A titanium dioxide photocatalyst is adhered to the aluminum fiber sound-absorbing material.
[0008]
The aluminum fiber sound-absorbing material itself used in the present invention is conventionally known as shown in Japanese Patent Publication No. 5-13517 of the present applicant, and is formed by press-molding aluminum fibers having a thickness of several hundred μm. It is plate-shaped. This aluminum fiber sound-absorbing material is excellent in sound-absorbing properties, and since it is an aggregate of fine fibers, its surface area is very large and the carrying area of the photocatalyst increases, so that the ability to remove nitrogen oxides is large.
[0009]
Titanium dioxide is often used as the photocatalyst, and is activated by receiving ultraviolet light having a wavelength of 300 to 400 nm, and exhibits a strong oxidizing power. Of these, the anatase type is desirable because of its high activity. Many titanium dioxide photocatalysts are fine particle materials, and in order to adhere to aluminum fibers, a method of applying and drying titania sol obtained by solating titanium dioxide particles, or a method of applying a paint using a ceramic binder There is. Both methods can be dried at room temperature, but the adhesion is improved by applying a baking treatment of about 100 to 250 °. In addition, if a silica-based ceramic material is preliminarily treated on the surface of aluminum fibers, adhesion to the photocatalyst and durability can be improved. In addition to silica, a material used as an inorganic binder can be used for the primer treatment.
[0010]
The soundproof wall of the present invention configured as described above is installed on both sides of an automobile exclusive road or a road with a large traffic volume of the automobile, and is made of an aluminum fiber sound absorbing material having excellent sound absorbing characteristics at the upper end of the sound insulating wall 1. Since the sound absorbing cylinder 2 is arranged, sound waves diffracted outside the road beyond the upper end of the soundproof wall are attenuated, and the soundproof effect can be enhanced without increasing the height of the entire soundproof wall.
[0011]
Further, the exhaust gas generated from the automobile rises along the sound insulation wall 1 and flows to the outside so as to wrap around the surface of the sound absorbing cylinder 2. The sound absorbing cylinder 2 is made of an aluminum fiber sound absorbing material to which a photocatalyst such as titanium dioxide is attached. Therefore, the nitrogen oxides in the exhaust gas are oxidized by the photocatalyst to be removed as nitrate ions. At this time, since the sound absorbing cylinder 2 protrudes from the sound insulating wall 1, the rising exhaust gas tends to stay around the sound absorbing cylinder 2, and the contact time with the photocatalyst becomes longer, so that an excellent removal effect is obtained. Moreover, since the sound absorbing cylinder 2 is located at the upper end of the soundproof wall, it is easy to effectively receive ultraviolet rays from the sun, and a removal effect superior to the case where a photocatalyst is attached to the vertical soundproof wall 1 can be obtained. Needless to say, if the photocatalyst is also attached to the vertical sound insulation wall 1, the contact area with the exhaust gas becomes large, so that a more excellent removal effect can be obtained.
[0012]
Photocatalysts such as titanium dioxide can oxidatively decompose organic substances in addition to nitrogen oxides. For this reason, if the photocatalyst is attached to the sound absorbing cylinder 2 as described above, there is an effect that the dirt adhering to the sound absorbing cylinder 2 can be decomposed and the soundproof wall can be kept clean. The aluminum fiber sound absorbing material is not corroded by nitric acid generated by oxidation of nitrogen oxides.
[0013]
Further, in the third embodiment shown in FIG. 3, a decompression means 4 such as a fan is provided to decompress the inside of the sound absorbing cylinder 2, and exhaust gas is actively sucked into the interior from the periphery of the sound absorbing cylinder 2. As a result, the contact efficiency between the exhaust gas passing through the aluminum fiber sound-absorbing material constituting the sound-absorbing cylinder 2 and the photocatalyst is increased, and the nitrogen oxide removal effect can be further enhanced.
[0014]
Since the soundproof wall of the present invention described above requires ultraviolet rays, the effect of removing nitrogen oxides is reduced in rainy weather or nighttime when ultraviolet rays from the sun do not reach. Therefore, in the fourth embodiment shown in FIG. 4, the ultraviolet lamp 3 is disposed inside the sound absorbing cylinder 2, and the photocatalyst is also attached to the inner surface of the sound absorbing cylinder 2. With such a structure, the photocatalyst adhering to the inner surface of the sound absorbing cylinder 2 is activated by the ultraviolet light from the ultraviolet lamp 3 even in rainy weather or at night, and the removal of nitrogen oxides in the exhaust gas and the decomposition of dirt are advanced. be able to.
[0015]
【The invention's effect】
As described above, the soundproof wall of the present invention is a sound absorbing cylinder made of an aluminum fiber sound absorbing material to which a photocatalyst such as titanium dioxide is attached, and is arranged along the upper end of the sound insulating wall. There is an advantage that an excellent nitrogen oxide removal effect and antifouling effect can be exhibited. Further, when combined with an ultraviolet lamp or a pressure reducing means inside the sound absorbing cylinder, a more excellent removal effect of nitrogen oxides can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment.
FIG. 2 is a cross-sectional view showing a second embodiment.
FIG. 3 is a cross-sectional view showing a third embodiment.
FIG. 4 is a cross-sectional view showing a fourth embodiment.
[Explanation of symbols]
1 sound insulation wall, 2 sound absorbing tube made of aluminum fiber sound absorbing material, 3 ultraviolet lamp, 4 pressure reducing means

Claims (2)

A sound-insulating wall in which a sound-absorbing cylinder is arranged along the upper end of the sound-insulating wall, the sound-absorbing cylinder is made of an aluminum fiber sound-absorbing material to which a photocatalyst is attached , and the sound-absorbing cylinder is formed with an outer diameter larger than the thickness of the sound-insulating wall, A soundproof wall characterized in that the photocatalyst is present over the surface, inside and inside, and has means for reducing the pressure inside the sound absorbing cylinder, and an ultraviolet lamp is disposed inside the sound absorbing cylinder.       The soundproof wall according to claim 1, wherein a photocatalyst is attached to the surface of the soundproof wall.

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