JPS591914B2 - Sound reduction device for air passages such as air conditioning return vents - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound reduction device in a ventilation passage such as an air conditioner return air vent, and in particular, the invention relates to a sound reduction device in a ventilation passage such as an air conditioner return air vent, and in particular, two or more partition walls that are inclined in different directions and have ventilation openings are installed in the ventilation passage. , reduce noise while ensuring smooth ventilation.

Complete noise reduction can be achieved by sealing the ventilation passages, such as with walls of sound-insulating structure, but the purpose of ventilation is obstructed;
On the other hand, if the ventilation path is completely opened, although ventilation becomes smooth, shielding and reduction of noise will be hindered.

Therefore, in the past, most return air vents in air-conditioned rooms were designed to ensure ventilation and reduce noise by installing baffles alternately on both sides of the ventilation path to form a maze shape, making the ventilation meander. .

However, such a sound reduction device has the disadvantage that the degree of sound reduction is extremely low.

In particular, a system in which an air-conditioning machine room is provided in the middle floor of a multi-story building and air-conditioning equipment is installed there is beginning to be widely adopted because it is suitable for disaster prevention, hot control, and convenience of partial operation.

However, the problem in this case is the noise generated in the air conditioning machine room.

In other words, because it is the middle floor of a multi-story building, the number of living rooms nearby is double compared to conventional underground machine rooms, etc.
The effects of noise generated from the air conditioning machine room become a dog.

Therefore, it has been strongly desired to improve the conventional sound reduction device for air passages.

This invention was completed as a result of research by the inventors based on the above technical problem, and its purpose is to reduce the volume while ensuring ventilation in air passages such as air conditioning return vents. The purpose is to reduce the volume in the low frequency range (125, 250 Hz), which has been considered difficult in the past. The purpose is to downsize the space and to improve construction reliability by making it possible to unitize the device.

That is, this invention provides a ventilation path 1, its side wall 2 and floor 3.
Two or more partition walls 4 are installed such that each partition wall 4 is inclined with respect to one or both of The side partition walls 4 are installed so that the inclinations are opposite to each other, and the side partition walls 4 have a V-shaped cross section.
A sound reduction device for a vent such as an air conditioner return air vent, characterized in that a trapezoidal expansion chamber 6 whose cross section is approximately square or triangular is formed in the side walls 2, the ceiling and the floor 3 which form 3. Pertains to.

The inventors attempted the following experiments until completing this invention.

First, there are two types: a labyrinth shape in which vertical baffle plates 7 are installed alternately on both sides of the ventilation passage 1 (Fig. 1C), and a labyrinth shape in which both baffle plates 7 are inclined in the same direction (Fig. 1B). ) and a labyrinth shape (FIG. 1A) in which two baffle plates T are tilted in opposite directions, the volume reduction was measured at each frequency.

FIG. 1C shows the configuration of a conventional sound reduction device.

Also, the 70 angle of the baffle board for Doujin and Doujin B is 8 to the floor 3.
It is 0 degrees.

The first diagram is a graph showing the relationship between sound frequency and volume reduction.The results of Figures 1A, 1B, 1C, and 1C are shown in the same graph.

According to this, it was found that the volume reduction was greater in types A and B, in which the baffle plate 7 was tilted, as opposed to type C, in which the baffle plate 7 was vertical.

Next, FIG. 2 shows an experiment on a labyrinth shape in which the baffle plate 7 is inclined with respect to the side wall 2.

E is a conventional labyrinth shape similar to FIG.

The angle of the baffle plate 70 in A-D is 70 with respect to the side wall 2.
degree.

It is a graph showing the relationship between sound frequency and volume reduction in each format of 1″- and A-H.

In this case as well, the type in which the baffle plate 7 is inclined increases the volume reduction in almost the entire frequency range.

Furthermore, when looking at each format of A to D, it can be seen that formats A and H, in which the baffle plate 7 is inclined in the shape of a square, have a large volume reduction, especially in the bass range.

As mentioned above, in the experiments shown in FIGS. 1 and 2, the baffle board 7 was installed at an angle with respect to the floor 3 or the side wall 2, and in particular, the baffle board 1 was installed at an inclination in a square shape. was found to be a condition for increasing the volume reduction.

In addition, in conventional maze-shaped devices, a practically sufficient amount of sound reduction in the mid-to-high range can be obtained by lining the inner lining with a sound absorbing material, but in the low frequency range, the sound absorption coefficient of the lining material is generally small. Due to this, the volume reduction is not large.

Therefore, as a means to increase the volume reduction in the low frequency range, the width of the maze is increased, the inner lining material is made of a thick sound-absorbing material with a high sound absorption coefficient, and the inner lining material has a sound-absorbing structure with an air layer behind it. , increasing the number of inner labyrinths, etc., but all of these methods have the disadvantage of increasing the overall size of the sound reduction device, so they are not suitable for practical application. isn't it.

Therefore, in order to improve the characteristic that the volume reduction in the bass range is small in the labyrinth shape, a partition wall 4 having a ventilation hole opened in the ventilation path 1 is used in place of the conventional baffle plate T. An experiment was conducted considering a format in which an expansion chamber 6 was formed between the two, thereby reducing the air flow passage area.

FIG. 3 is a graph showing an experiment in forming this expansion chamber 6 and the results.

FIG. 3A shows a form in which the expansion chamber 6 is formed, here formed by two partition walls 4), and one ventilation port 5 is opened in each of both corner walls 4.

The area ratio between the partition wall 4 and the ventilation hole 5 is 5:1°10 here.
Experiments were conducted on three types of ratios of 1.15 to 1.

The expansion ratio m is respectively expressed here as 5.10.15.

The conventional maze shape shown in FIGS. 1 and 2 is also shown in FIG. 3B, and its reduced volume is also shown in the graph in C compared to the previously described format.

As is clear from this graph, by providing the expansion chamber 6, the volume reduction had a maximum value in the bass range, and the volume reduction tended to increase in proportion to the expansion ratio. .

Furthermore, as per the experiment shown in FIGS. 1 and 2, it has been found that installing the baffle plate 7 at an angle with respect to the side wall 2 or the floor 3 is effective in increasing the volume reduction. The volume reduction was determined by tilting the partition wall 4 forming the expansion chamber shown in FIG. 3A with respect to the side wall 2.

This experiment is shown in FIG. In both cases, the expansion ratio m is lO.

C is the same type as FIG. 3A, and A is a type in which the partition walls 4 are inclined in the same direction, and B is a type in which the partition walls 4 are inclined in the opposite direction to form a rectangular shape.

The results are shown in graph D.

According to this, the type in which the partition wall 4 constituting the expansion chamber 6 is inclined tends to have a greater reduction in volume than the type C in which the partition wall 4 is inclined, and has no slope, across almost the entire frequency range, and especially It has been found that type B, in which the expansion chamber 6 has a triangular cross section, can increase the volume reduction that was depressed in the bass range, and can obtain a large volume reduction.

Furthermore, when the volume reduction was subsequently measured for the configuration in which the expansion chamber 6 was made triangular as described above, almost no change in the volume reduction was observed in either type A or B in FIG.

Therefore, using a substrate having the dimensions and shape shown in FIG. 5B and an expansion ratio of 10, the following experiment was conducted to examine the effect of shape change on the volume reduction.

Figure 6 shows experiments in which the expansion ratio was set to 10 and the width of the ventilation passage was varied.As is clear from graph D, overall there is little change in the sound attenuation characteristics. The smaller the width, the greater the volume reduction in the 80-100 Hz range, and the smaller the volume reduction in the 160 Hz range.

FIG. 7 shows the results of changing the apex angle θ formed by the partition walls 4 of the expansion chamber 6 having a triangular cross section.
, the state in which the apex angle θ is changed to 20 degrees, 40 degrees, and 60 degrees is A, and the results are shown in graph C.

According to this, there is no noticeable change in volume reduction in the bass range,
It was found that in the mid-to-high range, the smaller the apex angle θ, the greater the volume reduction.

FIG. 8 shows the results of testing the changes in the volume reduction by changing the expansion ratio m by changing the opening area of the ventilation port of the partition wall 4.

The expansion ratio m is 25 for A and 5 for B. C was 10, and as a result, a sound reduction characteristic as shown in graph D appeared.

In other words, it was found that the volume reduction increases in proportion to the expansion ratio in almost the entire frequency range.

When the expansion ratio m is 10, the volume reduction is approximately 2 when the expansion ratio m is 2.5.
It showed twice the value.

FIG. 9 shows a test of volume reduction between the type A in which three partition walls 4 are used and two expansion chambers 6 are connected, and the basic type B. The results are shown in graph C.

In this case, the volume reduction is approximately parallel over the entire frequency range, and the volume reduction is approximately 6 to 7 dB greater than the basic type B in which the expansion chambers 6 are continuous.

FIG. 10 shows a test example in which the position of the ventilation hole 5 in the partition wall 4 was changed as shown in A and B (expansion ratio 10).

Regarding the position of the ventilation port 5 in the partition wall 4, experiments on air resistance showed that type B has a smaller wind speed deviation on the return air port surface than type A, which is preferable. Since there is no significant difference in the volume reduction between A and B, it is clear that either of these methods can be adopted.

Further, FIG. 11 shows the sound reduction characteristics when the basic shape shown in FIG. 5B is coated with a sound absorbing material (expansion ratio: 10).

A is a state in which the entire sound absorbing material is lined inside, B is only the expansion chamber 6,
Graph C shows a state in which the sound absorbing material is applied only on the eye side, and D shows a state in which the sound absorbing material is not insulated. Graph E shows the sound reduction in each of these cases.

According to this, the effect of the inner patch is 80 to 160H in the bass range.
There was no noticeable difference in z, but in the frequency range of 200 Hz or higher, there was a clear tendency to increase the reduced sound volume compared to when no inner patch was used.

In addition, in the mid-high range in the figure, the volume reduction of A compared to D is approximately equal to the sum of the volume reduction compared to B and COD, so the volume reduction tends to increase in proportion to the inner pasting area. It was observed.

For example, in graph E, when looking at the actual 2KHz range, the volume reduction is 42 dB for A, 31 dB for B, and 28 dB for C.
Compared to Hikari D's reduced volume of 17 dB, A is 25 dB louder, B is 14 dB louder, and C is 11 dB louder.
It is large in dB.

Then, the difference in volume reduction between B and COD is 14dB+1
1 dB=25 dB, which corresponds to the difference in volume reduction between A and D of 25 dB.

In the experimental examples shown in Figures 1 to 11 above,
The direction of arrow X is the direction of air intake, and the opposite direction is the direction of sound propagation.

The scale at the top of each graph is the frequency scale in the actual construction state, and the corresponding frequency scale in the model is shown at the bottom.

Furthermore, all frequencies explained in this specification are actual numerical values.

These air resistance values were measured by changing the number of expansion chambers, expansion ratio, shape of ventilation holes, etc., and the results are shown in FIG.

This measurement was made based on the basic shape shown in FIG. 5B.

As a result, it was found that the practical air resistance coefficient was selected to be about 3 to 6, and therefore, it was sufficient for practical use.

According to the present invention, two or more partition walls 4 which are inclined with respect to one or both of the side wall 2 and the floor 3 are installed in the ventilation passage 1 so as to block the ventilation passage, and the partition walls 4 are ,
The ventilation holes 5 are opened, and the slopes of the adjacent partition walls 4 are opposite to each other, and both corner walls 4 are installed so as to form a V-shaped cross section. A sound reduction device in a ventilation passage such as an air conditioner return air opening has been completed, which is characterized by forming an expansion chamber 6 in the ceiling and floor 3.

FIG. 13 shows a typical example thereof.

In this embodiment, two partition walls 4 are used to form one expansion chamber 6, and each partition wall 4 has a circular ventilation port 5, which is provided at a return air port of an air conditioning machine room.

Note that the shape of the ventilation hole 5 may be square, but a circular shape or a shape close to this has less air resistance.

The return air then flows into the air conditioning machine room as indicated by arrow Y in the figure.

FIG. 14 is an enlarged cross-sectional view of FIG. 13.

The two partition walls 4b are surrounded by a frame material 8, a reinforcing material 9 is incorporated inside, glass wool 10 is filled on both sides of the reinforcing material 90, and a decorative board 11 is applied to the outer surface to form a unit.

The periphery of the ventilation hole 5 is formed by a cylindrical frame.

The side wall 2 on the right side in the return air direction indicated by arrow Y is a partition between the air conditioning machine room and other rooms.
A mortar 13 is filled in between.

Similarly to the partition wall 4, the left side wall 2 in the return air direction has a frame member 141 and a reinforcing member 15. It is made into a unit by glass wool 16 and decorative board 17, and this is attached to the right side wall 2.
The other side of the partition wall 4 is fixed to the left side wall 2 via a bracket 18.

Incidentally, the distance between the two side walls 2 is 1350+u+, the thickness of the partition wall 4 is 80 mm, the distance between the brackets 12 that fix both corner walls 4 to the side walls 2 is 1200 +++ib between the bent parts, the diameter of the ventilation hole 5 is 840 mm, and the distance between the brackets 12 that fix both corner walls 4 to the side walls 2 is 1200 + The angle of the wall 4 is 40 degrees, and the distance between the closest parts of both corner walls 4 is 100 m - partition wall 4
The height of is 2125 mg.

Although not shown, the ceiling board is also made into a unit.

The dimensions of these parts may be changed as appropriate depending on the characteristics of the sound to be reduced.

As is clear from the above, according to the present invention, it is possible to reduce the volume while ensuring ventilation in the air passage such as the air conditioner return vent.

In particular, this invention has a remarkable effect on sound reduction in the low range, which was conventionally considered to be unsuitable, and has therefore succeeded in reducing sound in all sound ranges.

Furthermore, according to this invention, the space required for the partition wall can be reduced by reducing the number of baffles in the conventional labyrinth type, and the device can also be made into a unit, making it possible to perform on-site installation work. Therefore, a sound reduction device with excellent accuracy was obtained.

Furthermore, according to this invention, since the sound reduction is large, it is also possible to omit the sound-absorbing material that was conventionally attached to air conditioning equipment rooms, etc., and this also has the effect of being excellent in economical efficiency in conjunction with the above-mentioned miniaturization. .

[Brief explanation of the drawing]

FIG. 1 to FIG. 12 show experimental examples until the completion of the present invention. Figure 1 is an experimental example of the relationship between the installation angle of the baffle board relative to the floor and the volume reduction.A is a perspective view of two baffle boards tilted in a V-shape; FIG. 2 is a perspective view of the two baffle plates tilted in the same direction, a perspective view of the two baffle plates perpendicular to each other, and a graph showing the relationship between frequency and volume reduction of A-C. Figure 2 is an experimental example of the relationship between the mounting angle of the baffle plate to the side wall and the volume reduction. A perspective view of the two baffle plates tilted in the same direction; C is a perspective view of the two baffle plates tilted in the opposite direction to A; D is a perspective view of the two baffle plates tilted in the same direction as B. E is a perspective view of a state in which the two baffle plates are vertical, and F is a graph showing the relationship between the frequency of A and E and the volume reduction. Figure 3 shows an experimental example of volume reduction when an expansion chamber is formed by a partition wall. Perspective view in vertical position, C.A. It is a graph which shows the relationship between the frequency of B and the volume reduction. Figure 4 is an experiment on volume reduction when changing the angle of the partition wall, A is a perspective view of the partition wall tilted in the same direction;
B is a perspective view of the partition walls tilted in different directions to form a V-shape, C is a perspective view of the two partition walls perpendicular, and D is A.
It is a graph showing the relationship between the frequency of −C and the volume reduction. Fig. 5 is a perspective view of the basic structure of this invention completed as a result of the experiments shown in Figs. Perspective view B is a perspective view with a partition provided only on the ventilation inlet side. Figure 6 is an experiment on volume reduction when changing the width of the air passage.A is a perspective view of the air passage with a narrow width, and B is a perspective view of the air passage with a narrow partition on the ventilation inlet side. Perspective view of installed state, C
1 is a perspective view of a state in which a wide partition is provided on the ventilation inlet side of the ventilation path, and a graph showing the relationship between the frequency of D and AC and the volume reduction. Fig. 7 is an experiment on volume reduction when changing the angle of the partition wall, A is a plan view showing the state of change in the angle, B is a perspective view when the angle is a specific angle, and C is A. It is a graph showing the relationship between the frequency and the volume reduction. Figure 8 is a test of volume reduction when the expansion ratio is changed. A is a perspective view when the expansion ratio is 2.5, B is a perspective view when the expansion ratio is 5, and C is a perspective view when the expansion ratio is 10. It is a perspective view of , and a graph showing the relationship between the frequency of D and AC and the volume reduction. Figure 9 shows a test of volume reduction when changing the number of expansion chambers, A is a perspective view with two expansion chambers formed, B is a perspective view with one expansion chamber formed, and C is a perspective view with one expansion chamber formed. This is a graph showing the relationship between the frequencies of A and H and the volume reduction. Figure 10 is a test of sound reduction when the opening position of the ventilation hole is changed. A perspective view of the device opened to the side, and C is a graph showing the relationship between the frequencies of A and B and the volume reduction. Figure 11 shows a test of sound reduction when changing the position of the inner lining of the sound absorbing material, A is a plan view with the entire interior lining, B is a plan view with only the expansion chamber lining, and C is a plan view with the inner lining only inside the expansion chamber. D is a plan view of a state where only the entrance side is applied internally, D is a plan view of a state where no internal application is applied, and E is a graph showing the relationship between A-D frequency and healing amount. FIG. 12 is a table showing air resistance values of the sound reduction device in each form. FIG. 13 is a perspective view showing an embodiment of the present invention, and FIG. 14 is an enlarged plan view of FIG. 13. In addition, in the figure, 1 is a ventilation path, 2 is a side wall, 3 is a floor, 4 is a partition wall,
5 is a ventilation hole, and 6 is an expansion chamber.

Claims (1)

[Scope of Claims] 1. Two or more partition walls are installed in the ventilation path, each of which is inclined with respect to one or both of the side wall and the floor, so that each partition wall individually blocks the ventilation path, and each partition wall has a ventilation path. The openings are opened and the slopes of the adjacent partition walls are opposite to each other, and the side partition walls are installed so as to form a V-shaped cross section, so that the adjacent side partition walls, the side walls, the ceiling and the floor forming a ventilation path. 1. A sound reduction device for a vent such as an air conditioner return air vent, characterized in that a trapezoidal expansion chamber with a triangular or approximately triangular cross section is formed. 2. A sound reduction device for a vent such as an air conditioner return vent, characterized in that the area ratio between the partition wall and its vent is approximately 5:1 to 10:1.