JPS60200041A - Sound-proof louver - Google Patents

Abstract

PURPOSE:To realize a high performance of sound elimination with less resistance of air passage by a method wherein vanes are formed to have a V-shaped section and a horizontal passage is not provided with respect to a direction of transmittance of sound. CONSTITUTION:A frame 28 is arranged at a communication opening 26, vanes 30 having inverted V-shaped section are arranged in the frame 28 in a desired spaced-apart relation in their vertical direction and the vanes 30 are constituted by the surface plates 32 with inverted V-shape and sound absorption material 34 of inverted V-shape. Further, the lower ends 36 of the vanes 30 are arranged in such a way as they may be located below the top parts 37 of the vanes 30 and a horizontal passage is not formed in a direction of transmittance of sound, thereby it is made possible to realize a high performance of sound absorption with less resistance of air passage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a soundproof louver, and particularly to a soundproof louver provided at a communicating entrance of a wall, a door, a duct, or the like.

[Prior art]

The structure of a conventional soundproof louver is shown in FIG. Immediately
A rectangular frame 14 is provided in the opening 12 of the building wall lO, and within this frame 14, a plurality of blades 16 are arranged at predetermined intervals in the vertical direction with the blades 16 tilted with respect to the air flow direction. ing. The blade 16 is composed of a surface plate 18, a sound absorbing member 4A20 provided inside the surface member 18, and a bunch board 22 provided on the lower surface of the sound absorbing member 4A20.

However, in the conventional soundproof louver configured as described above, although the sound absorbing material 20 is loaded for the purpose of soundproofing, the sound travels straight through the gap between the blades 16 and 16 due to the straight-line nature of the sound. No good sound deadening effect can be obtained. Therefore, it is conceivable to increase the thickness of the sound absorption jrA' 20 to improve the sound absorption coefficient, or to increase the length and depth of the blades 16 to improve the amount of damping. However, if such measures are taken, the air resistance during ventilation will increase, resulting in an increase in the power of the ventilation, and if the depth of the blades 16 is increased, the soundproof louvers that will be attached to the connecting entrance on the wall will be damaged. ζ As shown in Fig. 1, it becomes thicker than the wall thickness and protrudes from the wall, causing an unfavorable appearance.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a soundproof louver that has low airflow resistance and has a sufficient damping amount despite its thin overall thickness. There is.

[Summary of the invention]

A plurality of blades arranged horizontally in the communication openings of walls, doors, ducts, etc. are provided in the vertical direction. In a soundproofing louver which is arranged at a predetermined interval and further has a sound absorbing material attached to the back side of the surface plate constituting the upper surface of the blade, the angle formed by the inverted ■-shape of the blade is 55° to 6°.
It is characterized by being within a range of 5°.

〔Example〕

Preferred embodiments of the soundproof louver according to the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG.
is formed, and a soundproof louver is arranged in this communication opening 26. A rectangular frame 28 is disposed in this communication gateway portion 26, and within this frame 28, blades 30 having an inverted V-shaped cross section are provided at predetermined intervals in the vertical direction. As shown in FIG. 3, the blade 30 is composed of a face plate 32 formed in an inverted V shape and a sound absorbing JIA 34 in an inverted V shape attached to the back side of the face plate 32. Further, the lower end portion 36 of the blade 30 is arranged to be located below the top portion 37 of the blade 30 located below, so that no horizontal passage is formed in the sound propagation direction. Therefore, the passing sound cannot travel in a straight line, but when passing through the path bent at the center between the blades, it repeatedly reflects and flows out, resulting in an extremely good silencing effect.

The operation of the embodiment according to the present invention configured as described in niJ is as follows.

As mentioned above, the blade 30 has an inverted V-shaped cross section,
Since the single blades 30 formed in this manner are arranged vertically at predetermined intervals to constitute a ζ soundproof looper, no horizontal passage is formed in the sound propagation direction. Therefore, the sound passes through a path bent at the center formed between the inverted V-shaped blades 30, 30, where the sound flows out while being repeatedly reflected and absorbed. Therefore, the noise inside the building is effectively absorbed by the sound absorbing material 34, and the silencing effect is extremely effective.

In Fig. 4, the depth β1 of the soundproof louver, which is not shown in Fig. 3, is 150.
mm, the thickness β3 of the blade 30 is 30 mm, the gap between the blades 30 in the top-to-toe direction is 25 mm, and the angle θ formed by the blade 30 formed in an inverted V shape is variously changed. It shows the relationship between As can be seen from the curve in Figure 4, as the angle θ is gradually reduced from 180°, the noise level increases, but even if θ is set at an angle of 55° or less with an inflection point of 55° to 65". There is no increase in the silencing effect, and the subsequent silencing level remains constant.Therefore, there is an optimal point at the angle θ of the inverted V-shape of the blade 30 from the perspective of the silencing effect, which is approximately 55
It is clear that the optimum point exists in the range of 60° to 60°.

Curve 8 in FIG. 4 shows the relationship between the change in the angle θ of the blade 30 and the shape resistance coefficient E, which indicates the rate of pressure loss when airflow passes through the blade. As can be seen from curve 8 in FIG. 4, the shape resistance coefficient E increases exponentially as the angle θ decreases, and the pressure loss increases extremely at a final angle of 30° or less, which is considered to be practical. Generally, the pressure loss of this type of vent is 3
It is appropriate to design it so that it is 4 mmAq or less from the point of view of blowing power, and considering the passing wind speed to be about 3 m/S, it is desirable to keep the shape resistance coefficient E to 5 or less. Even taking these points into consideration, as can be seen from curve 8 in Fig. 4, at an angle of 55° to 65°, the shape resistance coefficient E as an expected value is about 5 or more), and the angle of this blade 30 is 5.
It can be said that 5° to 65° provides an extremely effective and economical optimum value.

In addition, by making the blade 30 in an inverted ■ shape, both sides of the blade (inlet and outlet portions) have a downward slope.
It has the advantage of effective noise directionality and does not radiate directly to ear level even if it hits a person, and can be said to be an extremely excellent shape as a soundproofing ventilation device.

As the sound damping performance of soundproof louvers gradually improves, there is a limit to the amount of sound damping that can be achieved only by the performance of the sound absorbing material and the opening area of the blades. The reason for this is that a certain proportion of the incident sound directly vibrates the metal blades and is secondarily radiated downstream as sound, which is what is called solid-state secondary propagation sound. Even if the spacing between the blades is narrowed at the expense of increasing pressure loss in order to increase the amount of silencing, it is impossible to reduce the noise below the level of the above-mentioned solid-state secondary propagation sound. FIG. 5 shows the relationship between the high density F of the surface plate 32 and the silencing volume when the sound absorption coefficient of the sound absorption moon 34 attached to the blade 30 according to this embodiment is changed. In the example shown in Figure 5, the frequency of the sound is 50
The sound absorption coefficients of curves A, B, and C are G = 9.05 (no sound absorption shrine) H = 0.
．． 3, I = 0.8.

Regarding the dimensions of the blade 30 at this time, the blade thickness -β2 and the gap 13 between the blades are tri, that is, the aperture ratio with respect to the total area is 50%. As can be seen from FIG. 5, in curve G with a low sound absorption coefficient, the degree of silencing does not improve significantly even if the surface density F of the surface plate 32 of the blade 30 increases, and it almost depends on the sound absorption coefficient. The mute volume is determined. As shown by curves H and I, it can be seen that as the sound absorption coefficient improves, the influence of the surface density F on the silencing level gradually increases. Looking at the state of change in this silencing iD, the areal density "Kg/rd
It can be seen that even if the areal density F becomes higher than 44, the silencing level does not change. It can be seen that regardless of the difference in sound absorption coefficient, l/i is the inflection point in all cases. For example, from the curve I with a sound absorption coefficient of 0.8, the high density F of the surface plate 32 of the blade 30 is 2 kg/r.
d had a damping noise of about 5 dB, but the areal density was 8K.
g/rri improves to about 13 dB. By setting the areal density F to 8 Kg/'+rr or more in this way, it is possible to minimize the vibrations of the blades 30 due to sound waves, effectively bring out the silencing performance of the sound absorbing moon 34, and increase the silencing Hv.

In addition, to give an example of the surface plate 32, the quality of the metal M wing is A.
If the thickness is ff (aluminum) and the specific gravity of Aj2 is 2.7, it is possible to maximize the sound deadening performance as a soundproofing ventilation device by making the thickness approximately 3 dragons or more. becomes.

FIG. 6 shows the relationship between the density J of the sound absorbing material (glass wool) 34 and the sound deadening i1). In the example shown in FIG. 6, the depth of the soundproof louver is 11 = 150 mm, the bending angle of the blade 30 is θ-60°, and the thickness of the blade 30 with the sound-absorbing moon is #2 =
28 mm, and the gap between the blades 30 is 13-30 mm. Under this N method, the density J of suction M+A is 10Kg/m to 160Kg/n? Figure 6 shows the change in the silencing 1"fD when the density is increased to 1"fD.As can be seen from Figure 6, when the density of the sound absorbing material 34 is increased from 10 kg/M to higher density, the silencing amount gradually increases until it reaches 80 kg/M. /n?~96 Kg/
n? Even if the inflection point is changed to a higher density one, no increase in silencing noise is observed. This is because the sound transmission component from the blade 3o itself becomes more dominant than the sound absorption effect, and the optimum value of the density of the sound absorbing material from the deadening sound is 80Kg/r.
r? ~96Kg/n? It can be seen that it is within the range of The pressure loss, which indicates the ventilation performance of a soundproof ventilation system, is 30.
It is mostly determined by the bending angle θ and the interval l13 between the blades 3o, and is hardly influenced by the density of the sound absorbing material 34. In this way, by setting the density of the sound absorbing material 34 to 80 kg/a or more, a sufficient sound deadening effect can be achieved.

Shielded rooms are used for measuring noise in various information devices such as computers and calibrating electronic devices.
It is made up of panels covered with conductive metals such as steel plates, aluminum plates, and copper plates, so it has a high sound-dampening effect. However, noise from the outside that enters through the ventilation holes that are opened for ventilation is a problem from the standpoint of environmental protection within the shielded room. The embodiment shown in Fig. 7 was developed from this point of view, and the blades 3o, 30(7) IJ1
A shielding wire mesh 4o is provided at the bent portion of the gap. The structure of the embodiment shown in FIG. 7 is the same as that of the embodiment shown in FIG. 2 except for the wire mesh 40, so the other explanations will be omitted. This wire mesh used for soundproof louvers 4
If the wavelength of the electromagnetic wave is λ, then if two conditions are satisfied: porosity of 50% or less and mesh pitch of 60 lines/λ or more, the reflection loss is approximately equal to that of a metal plate (η), and the same as that of a shield wall. It has a shielding effect. In Fig. 8, the horizontal axis shows the frequency f, and the vertical axis shows the shielding attenuation rate ALL.

In Figure 8, the straight line has a wire diameter of 0.3 mm and a pitch of 1.
This is a wire mesh using 0mm copper wire, and the straight line indicates a copper wire wire mesh with a wire diameter of 0°3111111 and a pitch of 10mm.
Straight line M indicates the shielding effect of a copper plate with a thickness of 0.3 mm. As can be seen from Figure 8, in the straight line with a porosity of about 49%, the shielding attenuation factor Alt exceeds 80% at frequencies below 50 MHz, which is a value close to the copper plate shielding ljj of the straight line M. . It can be seen that in the straight line where the porosity is about 94%, it is extremely reduced. From this, it can be seen that the wire mesh 40 used for the soundproof louver should be a wire mesh that satisfies the above conditions. In this way, wire mesh 40 is placed between the blades 30.
By arranging the wire mesh, it is possible to obtain a soundproof louver with better sound-damping and shielding performance with less ventilation resistance.In addition, the wire mesh is made of conductive material such as copper wire, steel wire, Monel metal wire, etc. for shielding electromagnetic waves. is used.

〔Effect of the invention〕

As explained above, according to the soundproof louver according to the present invention, a plurality of blades arranged horizontally in a communication opening of a wall, a door, a duct, etc. are provided in the top direction, and the blades have an inverted ■-shaped cross section. They are formed in a shape and are arranged at a predetermined distance from each other so as not to create a horizontal passage in the direction of sound propagation.
Further, in the soundproof louver in which a sound absorbing material is attached to the back side of the surface plate constituting the two sides of the blade, the nose angle of the inverted V-shaped blade is set in the range of 55° to 65°. Therefore, it is possible to provide a soundproof louver that has higher noise damping performance with less ventilation resistance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a conventional soundproof louver, FIG. 2 is a sectional view showing the structure of a soundproof louver according to the present invention, and FIG. 3 is an enlarged sectional view showing the main parts of an embodiment according to the present invention. , Figure 4 is an explanatory diagram showing the change in the amount of extinction when the angle of the inverted V-shaped blade is changed, and Figure 5 is an illustration showing the change in the amount of extinction when the surface density of the blade surface plate is changed. Explanatory diagram, Figure 6 is an explanatory diagram showing the change in the amount of damping when the density of the sound absorbing material of the blade is changed, Figure 7
The figure is an enlarged W1 side view showing the structure of another embodiment of the present invention, and FIG. 8 is an explanatory diagram showing changes in the shielding attenuation rate when the shape of the shield wire mesh is changed. 24...Wall surface, 26...Communication opening, 30...
-Blade, 32...Surface plate, 34...Sound absorbing material. Agent: Patent Attorney Kenzo Matsuura Figure 1 Figure 2 Figure 4 Figure 5 ■ F, (kg/m2) Figure 6, J (kQ/m3) Figure 7 Continuation of page 1 ■ Inventor Hajime Enso Department 0 Inventor Minoru Takahashi Inventor Takashi Kuribayashi 1-1-14 Uchikanda, Chiyoda-ku, Tokyo Hitachi Plant Construction Co., Ltd. 1-1-14 Uchikanda, Chiyoda-ku, Tokyo Hitachi Plant Construction Hitachi Plant Construction Co., Ltd., 1-1-14 Uchikanda, Chiyoda-ku, Tokyo

Claims (1)

[Claims] A plurality of blades arranged horizontally in the communication opening of a tttg surface, a door, a duct, etc. are provided in the vertical direction, and the blades have an inverted V-shaped cross section and a horizontally penetrating In a soundproof louver, which is arranged at a predetermined distance from each other so as not to create a path, and in which a sound-absorbing material is attached to the back side of the surface plate that constitutes the upper surface of the blade, angle bar 55
A soundproof louver characterized in that the angle is in the range of 65° to 65°. (2) The soundproof louver according to claim 1, wherein the surface plate has a surface density of 8 kg/rrr or more. (3) The soundproof louver according to claim 1, wherein the density of the sound absorption H is 8.0 kg/m or more. (4) The soundproof louver according to claim 1, characterized in that a conductive perforated abrasive material is vertically stretched between each of the blades arranged at predetermined intervals in the vertical direction. .