JP2007078322A - Duct having sound diminishing function, and duct type ventilator for building - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a duct for developing a sound diminishing effect in a wide range including intermediate and low frequency areas by controlling frequency as an sound insulation object. <P>SOLUTION: A sound inlet port 11 is provided on one end part of the duct 10 including a long sound propagation passage 13 in one direction. A sound outlet port 12 is formed on other end part of the duct 10, and a room 16 for forming a resonator is partitioned in the propagation passage 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a duct having a sound reduction function that can be used as ventilation equipment for buildings.

  In residential ventilation equipment, the ventilation openings provided on the side walls of the house are directly open to the outside through the duct, so that outside sound enters the room together with air ventilation, and room sound also leaks outside. End up.

  Conventionally, as a noise countermeasure at this type of ventilation port, one using a sound absorbing material that absorbs sound in the ventilation port is known. For example, the ventilation apparatus proposed in Japanese Patent No. 3184799 can be cited.

  By the way, in recent years, after new construction or renovation of a house, sick house syndrome that causes poor physical condition or health problems to residents due to volatile chemical substances and mite allergens generated from the building materials in the room has become a problem. As a countermeasure against sick houses, the Building Standards Law was revised in 2002, and the use of chemical substances, which are considered to be the cause, and the installation of mechanical ventilation equipment have become obligatory.

  In relation to such measures against sick houses, there is a background that regulations on buildings are being strengthened, and in ventilation equipment, a sufficient living function is ensured from the viewpoint of health and safety, and a quiet living environment is ensured. The importance of taking noise countermeasures is increasing.

Especially in apartment buildings, the problem of noise that enters with air from the vents has been a problem in the past, and it is necessary to continuously ventilate as a countermeasure against sick house, so the problem is that outdoor noise enters through the vents. Is expected to become more apparent. In addition, in the case of apartments, it is highly necessary to take measures not only to prevent noise but also to keep privacy so that indoor sound does not escape with ventilation.
Japanese Patent No. 3184799

  However, conventional noise countermeasures at ventilation openings use sound-absorbing materials that absorb sound only, so road noise, which is a typical noise source, is low even if the effect of reducing high-frequency noise can be obtained. Since the sound range is dominant, it has been pointed out that it is not very effective in the mid-low range below 500 Hz, which is particularly problematic as a physiologically unpleasant noise in the living environment.

  In addition, the surrounding environment varies and noise sources vary, and the range of noise varies from residence to residence.Therefore, there is a need to improve the sound insulation performance for a specific range of sounds according to the environment, or to reduce sound over a wide range of sounds. is there.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a duct that solves the problems of the prior art and that exhibits a sound reduction effect especially for low-frequency noise.

  Another object of the present invention is that it can be easily installed in a house, does not use a sound-absorbing material, has a simple structure, and has a sound reduction function that is effective in the low frequency range. An object of the present invention is to provide a duct type ventilator for buildings having a sound reduction function capable of achieving both ventilation functions.

  In order to achieve the above object, a duct having a sound reducing function according to the invention of claim 1 is provided with a sound inlet at one end of a duct forming a long sound propagation path in one direction, A sound outlet is formed at the other end of the duct, and a room for forming a resonator is partitioned in the propagation path.

  The duct having a sound reduction function according to the invention of claim 2 is provided with a sound introduction port at one end of a duct forming a long sound propagation path in one direction and the other end of the duct. A plurality of rooms in which a sound outlet is formed and a resonator is formed in the duct are continuously divided along the propagation path.

  In the second aspect of the present invention, it is preferable that the volume and the opening width of each of the plurality of rooms forming the resonator correspond to the frequency band of the sound to be reduced.

According to a second aspect of the present invention, a plurality of ribs having a surface perpendicular to the longitudinal direction of the duct are further arranged in the passage of the duct at a predetermined interval correlated with a frequency to be reduced. It may be. The plurality of ribs may be arranged with unequal intervals, and different frequency bands may be targeted for sound reduction.
According to a preferred embodiment, the resonator formed in the duct forms a resonator having a slit opening in a wall partitioning the resonator as a neck portion and a slit opening in a wall partitioning the resonator. It consists of a resonator having a pair of opposed plate pieces as necks, or a combination thereof.

  The building duct type ventilator according to the invention of claim 9 has a ventilation duct that forms a long ventilation passage in one direction communicating between the interior and the exterior of the building, and a ventilation opening at one end of the ventilation duct. The duct according to any one of claims 1 to 8, wherein the duct according to any one of claims 1 to 8 is provided as a ventilation duct in a building-type ventilator having a sound introduction port that also serves as a ventilation port and a sound outlet port that also serves as a ventilation port at the other end. It is characterized by comprising.

  According to the duct having a sound reduction function according to the present invention, it is possible to reduce the sound by targeting a certain frequency to some extent, and by controlling the volume, opening area, etc. of the resonance chamber, the frequency to be reduced can be controlled. In addition, the effect can be exhibited in a wide range of sound reduction including the mid-low range.

  Moreover, according to the duct type ventilator for buildings having a sound reduction function according to the present invention, the structure itself is simple without using a sound absorbing material, so that it can be easily installed in a house and is also specified. It is possible to achieve a balance between a sound reduction function corresponding to a wide sound range including mid and low sounds and an air ventilation function.

Hereinafter, an embodiment of a duct having a sound reduction function according to the present invention will be described with reference to the accompanying drawings.
First embodiment
FIG. 1 shows a duct according to a first embodiment of the invention. In FIG. 1, reference numeral 10 indicates a main body portion of the duct. The main body 10 of the duct is a long and narrow duct having a square cross section and a hollow inside. A sound inlet 11 is opened at one end of the main body 10, and a sound outlet 12 is opened at the other end. The sound that enters from the introduction port 11 propagates through the internal space of the duct as a propagation path 13 and exits from the outlet 12.

  In the duct according to the present embodiment, a room for forming a resonator (resonator) is defined in the propagation path 13 in order to add a sound reduction function. As shown in FIG. 1, in the duct body 10, the vertical partition wall 14 extends in the longitudinal direction from the end on the introduction port 11 side, and the horizontal partition wall 15 is bent at a right angle from the end of the vertical partition wall 14. The vertical partition wall 14 and the horizontal partition wall 15 form a resonance chamber 16 that forms a resonator. A slit 17 is formed in the vertical partition wall 14 forming the resonance chamber 16 as an opening at a substantially central position. In the embodiment of FIG. 1, the resonance chamber 16 is provided at a position close to the introduction port 11, but is not limited thereto, and may be provided at a position close to the outlet port 12. You may provide in the center of a duct.

  Next, the sound reduction effect in the duct configured as described above will be described.

  When a sound wave enters the propagation path 13 from the inlet 11 of the duct body 10, a part of the sound wave enters the resonance chamber 16 through the slit 17. The resonance chamber 16 has the same function as a Helmholtz resonator 18 as shown in FIG. In FIG. 2, in the resonator 18, when sound waves enter from the opening of the neck portion 19, the air inside the trunk 20 acts as a spring, and the mass of the air in the opening portion of the neck portion 19 plays a role as a weight. , Causing a single resonance. Due to this single resonance phenomenon, the impedance value changes immediately before the neck portion 19 and a kind of reflection occurs, so that the sound wave is difficult to propagate downstream. As a result, the transmitted wave does not easily reach the outlet 12 of the propagation path 13, and a sound reduction effect is produced.

ここで、ｃ：音速（ｍ／ｓ）
Ｓ：首部１９の開口面積（ｃｍ2）
Ｖ：胴２０の容積（ｃｍ3）
ｌ：首部１９の長さ（ｃｍ）
Δｌ：首部１９の補正 The Helmholtz resonator 18 can obtain a great sound reduction effect for a sound having a frequency given by the following equation (1).

Where c: speed of sound (m / s)
S: Opening area of the neck 19 (cm 2)
V: Volume of the trunk 20 (cm 3)
l: Length of neck 19 (cm)
Δl: correction of neck 19

  In the duct according to the present embodiment, the slit 17 substantially corresponds to the neck opening of the resonator 18, and the expression (1) is established by appropriately taking the correction Δl of the neck, and a specific sound reducing effect is obtained. The frequency can be predicted.

  In the case of the resonance chamber 16 in the duct of the present embodiment, S corresponds to the opening area of the slit 17, V corresponds to the volume of the resonance chamber 16, and l corresponds to the plate thickness of the slit portion. If an appropriate correction Δl value is obtained experimentally, the frequency can be calculated from the equation (1).

Therefore, in the duct according to the present embodiment, when sound waves enter the propagation path 13 from the introduction port 11, the sound is reduced with respect to sound in a specific frequency band determined from dimensions such as the volume of the resonance chamber 16 and the opening width of the slit 17. Demonstrate sound function. In other words, the dimensions of the resonance chamber 16 and the slit 17 may be determined with the aim of reducing sound in a specific frequency band.
In the embodiment of FIG. 1 described above, only one resonance chamber 16 is partitioned along the propagation path 13 in the main body portion 10 of the duct. However, in the embodiment of FIG. The plurality of resonance chambers 16 a, 16 b, 16 c, 16 d, and 16 e are continuously partitioned along the propagation path 13 by the horizontal partition walls 15 a to 15 e. These resonance chambers 16a, 16b, 16c, 16d, and 16e communicate with the propagation path 13 through slits 17a, 17b, 17c, 17d, and 17e, respectively.

  In the embodiment of FIG. 3, the lengths L1, L2, L3, L4, and L5 are gradually reduced in the resonance chambers 16a, 16b, 16c, 16d, and 16e. From the equation (1), each resonance chamber 16a, 16b, 16c, 16d, 16e has a frequency band with a sound reduction effect increasing in this order. For example, the resonance chamber 16a having the largest volume aims at a sound reduction effect in a band around 150 Hz, the length L1, L2, L3, such that the resonance chamber 16b is 300 Hz, the resonance chamber 16c is 450z, and the resonance chamber 16c is 600 Hz. When L4 and L5 are set, it is possible to improve the sound reduction performance mainly for sounds in the middle and low range.

  In the embodiment of FIG. 3, five examples of resonance chambers are shown. However, as long as the number of resonance chambers is long, more resonance chambers can be defined. In addition, the resonance chambers may have the same or different opening area and width, and the mode of arranging the resonance chambers having different sizes may be appropriately determined according to the noise situation or the like.

Second embodiment
Next, FIG. 4 shows a duct according to a second embodiment of the present invention. In FIG. 4, the duct body 10 is the same as that of the first embodiment, and a sound introduction port 11 is opened at one end, and a sound lead-out port 12 is opened at the other end. The propagation passage 13 extends in the longitudinal direction inside. Two resonance chambers 16a and 16b are formed by the vertical partition wall 14 and the horizontal partition walls 15a and 15b, and the resonance chambers 16a and 16b communicate with each other through slits 17a and 17b, respectively.

  In this second embodiment, a plurality of ribs 22a, 22b, and 22c having a surface perpendicular to the duct longitudinal direction are provided following the two resonance chambers 16a and 16b. In FIG. 4, the intervals X1, X2, and X3 of these ribs 22a to 22c are set so as to be gradually reduced toward the outlet 12 side, but are not limited thereto.

  The intervals X1, X2, and X3 of these ribs 22a to 22c are arranged at predetermined intervals that correlate with the frequency to be reduced. Specifically, this interval is determined by obtaining an interval at which a sound reduction effect is experimentally obtained for a certain band.

  For example, in the resonance chambers 16a and 16b, as described in the first embodiment, the lengths L1 and L2 are set so as to reduce the sound in a specific frequency band. And about the space | interval X1, X2, X3 of rib 22a thru | or 22c, changing space | interval X1, X2, X3 beforehand experimentally with respect to the frequency different from the sound reduction object in resonance chamber 16a, 16b, The sound insulation effect is measured, the correlation between the interval and the frequency having the sound insulation effect is examined, and an interval suitable for sound reduction aiming at a specific frequency may be set based on the correlation.

  In the duct according to the second embodiment, a sound reduction effect can be obtained in a wide band by the combination of the resonators 16a and 16b and the ribs 22a to 22c in the first embodiment. Compared to the sound-reducing action of the resonators 16a and 16b, the sound-insulating mechanism of the ribs 22a to 22c is complicated and not fully understood, but the sound propagating through the propagation path 13 is multiplexed on the ribs 22a to 22c. It is thought that the effect of reducing the sound is produced by combining the phenomenon of reflection and the phenomenon of sound interference.

Third embodiment
Next, FIG. 5 shows a duct according to a third embodiment of the present invention. In the embodiment of FIG. 5, the structure of the main body 10 of the duct is basically the same as that of FIG. 3, but the structures of the openings of the resonators 16a to 16e are different.

  In each of the resonators 16 a to 16 e, slits 17 a to 17 e of openings are formed by a pair of plate pieces 21. Each plate piece 21 hangs down from the vertical partition wall 14 into the resonators 16a to 16e so as to be bent, and is opposed in parallel to form an opening. The plate piece 21 corresponds to the neck opening of the Helmholtz resonator 18 shown in FIG. 2, and by adjusting the length, the resonance frequency can be adjusted without changing the ventilation area and the resonance chamber volume.

  If the neck portion is bent by the plate piece 21, there is an advantage that the width L dimension of the resonance chamber can be shortened when the same resonance frequency is aimed as compared with the case where the plate portion 21 is not bent. However, the width of the effective frequency band is narrowed. A number of resonators may be arranged in one duct, and in order to exert an effect for sound reduction over a wide band, a resonator having a bent neck portion and an unbent resonator may be combined to achieve a good balance.

  The embodiment of FIG. 6 is an embodiment in which the openings of the slits 17a and 17b of the resonators 16a and 16b are constituted by plate pieces 21 facing in parallel in the duct having the same structure as that of FIG.

  Next, as Example 1 and Example 2, the result of an experiment for actually examining the sound reduction performance will be described.

Example 1
FIG. 7A shows a reference duct composed of a duct having an internal dimension of 1800 mm in total length and a cross section of 100 mm × 100 mm. This reference duct is made of an aluminum plate having a thickness of 2.5 mm, and sound inlets and outlets are opened at both ends.

  In Example 1, as shown in FIG. 7B, a plurality of resonance chambers were partitioned inside the reference duct. There are 6 resonance chambers in total, of which 3 half have slits as in the first embodiment of FIG. 3, and the remaining 3 chambers have necks as in the third embodiment of FIG. It has a resonance chamber. The length of each resonance chamber is as shown in FIG.

Comparative Example 1
In Comparative Example 1, only ribs are set up at intervals of 100 mm, 90 mm, and 80 mm on the outlet side inside the reference duct.

Example 2
Example 2 is a duct in which Example 1 and Comparative Example 1 are combined, and corresponds to the second embodiment.

Experimental Conditions As shown in FIG. 8, a duct was inserted and installed in a passage that penetrates the wall separating the reverberation room and the anechoic room. A sound source and a speaker were installed in the reverberation room, and a microphone and an acoustic measurement device were installed in the anechoic room. Broadband noise (pink noise) including frequencies up to 10 kHz was radiated from the reverberation room speaker, and the acoustic power level radiated from the opening on the anechoic room side through the duct installed on the wall was measured. The sound intensity method was used for the measurement.

Experimental result
The measured experimental results are shown in the graph of FIG. In FIG. 9, the horizontal axis represents frequency, and the vertical axis represents insertion loss (dB). This insertion loss is based on the sound power level measured when the reference duct is inserted into the partition wall, and the first and second embodiments. The difference of the power level radiated | emitted to the anechoic chamber side when the comparative example 1 is inserted in a partition is calculated. Therefore, the higher the value on the vertical axis (the larger the positive value), the higher the sound reduction effect. In FIG. 9, Example 1 is represented by a black square plot, Example 2 is represented by a x plot, and Comparative Example 1 is represented by a black triangle plot.

In FIG. 9, in Example 1, a large sound reduction effect is obtained in the frequency range of 160 Hz to 1 kHz. In Comparative Example 1, it can be seen that a sound reduction effect is hardly obtained when the frequency is 1 kHz or less, whereas an effective sound reduction effect is obtained in the range of 1 kHz to 5 kHz.

  In Example 2, it is recognized that the frequency region having a sound reduction effect is expanded as if the graphs of Example 1 and Comparative Example 1 were superimposed. In this way, the sound reduction effect due to the resonator principle and the sound reduction effect due to the ribs are considered to work simultaneously and independently. An effective frequency band can be expanded.

Fourth embodiment
Next, FIG. 10 shows an embodiment in which the duct according to the first embodiment shown in FIG. 3 is incorporated in a residential ventilation unit.
In FIG. 10, reference numeral 40 indicates an outer wall. Sashes 41 a and 41 b are provided in the opening of the outer wall 40. In this embodiment, the main body 10 of the duct is attached along the upper frames of the sashes 41a and 41b. A ventilation port 43 at one end of the main body 10 of the duct opens to the outdoor side, a ventilation port 44 at the other end opens to the indoor side, and the duct forms a ventilation passage 45 that communicates the room with the outside. It is like that. The structure of the main body 10 of the duct is the same as the duct shown in FIG. 3 in that a plurality of resonance chambers 16a to 16d are formed along the ventilation passage 45, and the same reference numerals are used for the same components. The description is omitted.

  According to the duct type ventilator configured as described above, the ventilation passage 45 of the duct body 10 serves as the original ventilation passage and the sound propagation passage. The sound entering from the mouth 43 is rebounded by the impedance change by the resonance chambers 16a to 16d. As a result, the sound wave entering the room from the indoor ventilation port 44 is reduced. Without using a material, it is possible to prevent the outdoor noise from entering the room, and it is possible to configure a ventilator that has both a ventilation function and a sound reduction function. In the case of this embodiment, as explained in the first embodiment, the volume of the resonance chambers 16a to 16d and the opening area of the slits 17a to 17d are changed according to the environment around the house to be attached, which causes a problem as noise. It is also possible to reduce noise by aiming at the frequency that becomes.

  FIG. 10 shows an embodiment in which the duct main body 10 is attached along the upper frame of the sash 41a, 41b, but it may be attached along the vertical frame.

  Next, FIG. 11 shows an embodiment in which the duct of the second embodiment shown in FIG. 4 is incorporated in a ventilation unit of a house. The same components as those of the ducts of FIGS. 10 and 4 are denoted by the same reference numerals, and description thereof is omitted.

  According to the ventilation unit of FIG. 11, the ventilation passage 45 of the duct main body 10 serves as the original ventilation passage and the sound propagation passage, and as described in the second embodiment, the resonance chambers 16a to 16c. The effect of repelling sound waves by the sound and the sound reduction effect by the combined action of multiple reflections and interference by the ribs 22a to 22c overlap, so that a ventilation device having both a ventilation function and a sound insulation function can be configured. According to this embodiment, as described above, the frequency at which the sound reduction effect appears can be expanded over a wide range, which is effective for noise countermeasures from the low frequency band to the mid-high frequency band.

  As mentioned above, although this invention was demonstrated and mentioned with preferable embodiment, in the ventilation apparatus for buildings of this invention, you may make it use together with a sound-absorbing material by sticking a sound-absorbing material inside a duct.

The structure explanatory view of the duct by a 1st embodiment of the present invention. Explanatory drawing of the resonator of Helmholtz equivalent to the resonance chamber formed in a duct. Structure explanatory drawing which shows other embodiment of the duct by 1st Embodiment of this invention. Structure explanatory drawing of the duct by 2nd Embodiment of this invention. The structure explanatory view of the duct by a 3rd embodiment of the present invention. Structure explanatory drawing of the other duct by 3rd Embodiment of this invention. Explanatory drawing of the duct of the Example by this invention. The figure explaining the implementation conditions of the sound reduction performance measurement test by an Example. The graph which shows the measurement result of the sound reduction performance by an Example. The perspective view which shows embodiment which applied the duct of 1st Embodiment of this invention to the ventilation unit of a house. The perspective view which shows embodiment which applied the duct of 2nd Embodiment of this invention to the ventilation unit of a house.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Duct body part 11 Inlet port 12 Outlet port 13 Propagation passage 14 Vertical partition wall 15 Horizontal partition wall 16 Resonance chamber 17 Slit 18 Helmholtz resonator 19 Neck portion 20 Body 21 Plate piece 22 Rib

Claims (9)

  A sound introduction port is provided at one end of a duct that forms a long sound propagation path in one direction, and a sound outlet is formed at the other end of the duct to form a resonator. A duct having a sound reduction function, characterized by being partitioned in a propagation path.   A sound inlet is provided at one end of the duct that forms a long sound propagation path in one direction, and a sound outlet is formed at the other end of the duct, thereby forming a resonator in the duct. A duct having a sound reduction function, characterized in that a plurality of rooms are continuously partitioned along the propagation path.   The duct having a sound reduction function according to claim 2, wherein the volume of each of the plurality of rooms forming the resonator and the opening width of the neck portion are different corresponding to the frequency band of the sound to be reduced.   The plurality of ribs having a plane perpendicular to the longitudinal direction of the duct are arranged at predetermined intervals in the passage of the duct that correlate with a frequency to be reduced. Duct with sound reduction function.   The duct having a sound reduction function according to claim 4, wherein the plurality of ribs are arranged at uneven intervals so that different frequency bands are targeted for sound reduction.   The sound reduction function according to any one of claims 2 to 5, wherein the resonator formed in the duct includes a resonator having a slit opening in a wall partitioning the resonator as a neck portion. Having a duct.   The resonator according to claim 6, wherein the resonator formed in the duct includes a resonator having a pair of opposed plate pieces forming necks formed in slits opening in a wall partitioning the resonator. Duct with sound function.   8. The reduction according to claim 6, wherein the resonator formed in the duct is an arbitrary combination of a resonator having the slit as a neck portion and a resonator having the plate piece as a neck portion. Duct with sound function.   It has a ventilation duct that forms a long ventilation passage in one direction communicating with the interior and exterior of the building, and a sound introduction port that doubles as a ventilation port is provided at one end of the ventilation duct, and a ventilation port is provided at the other end. 9. A building duct type ventilator having a sound outlet that also serves as a building duct, wherein the duct according to any one of claims 1 to 8 is incorporated as a ventilation duct. Type ventilator.

Images