JP5713957B2 - Silencer for ventilation duct - Google Patents

Description

  The present invention relates to a silencer for a ventilation duct that silences noise entering the room through a ventilation opening.

  Conventionally, houses and stores have been provided with ventilation ducts for forcibly discharging kitchen air to the outdoors. Since this ventilation duct connects the ventilation device and the ventilation port communicating with the outdoors, there is a problem that outdoor noise is transmitted indoors.

  Therefore, for example, as in Patent Document 1, it is known to connect a duct silencer having an air layer and a sound absorbing material between an inner cylinder and an outer cylinder to a ventilation duct.

JP 2007-170739 A

  However, in the silencer of the above-mentioned Patent Document 1, the noise reduction volume of 250 Hz of noise is less than 5 dB, but the high frequency range is silenced by 30 dB or more by the sound absorber, which is considered to be excessive performance.

  The present invention has been made in view of this point, and an object of the present invention is to mute the high frequency range and low frequency range of noise transmitted to the ventilation duct from outside in a well-balanced manner.

  In order to achieve the above object, in the present invention, the silencer is provided with a silencing chamber for silencing a high frequency range and a silencing chamber for silencing a low frequency range.

Specifically, in the first invention, an inner cylinder connected to a ventilation duct that communicates between the ventilation device and the ventilation opening, which leads from indoor to outdoor,
A silencer for a ventilation duct provided with an outer cylinder that encloses the outside of the inner cylinder in a sealed manner,
The outer cylinder includes a first silencing chamber in which a silencing member is incorporated, and a second silencing chamber that is provided in the first silencing chamber in an axial direction and does not incorporate the silencing member.
The inner cylinder is
A plurality of first communication holes for communicating between the first silencing chamber and sending noise from the ventilation port to the silencing member;
Have a plurality of second communication holes aligned in the axial direction that communicates between the second silencing chamber,
A liquid guide portion not provided with the first communication hole is formed on the lower surface side of the first silencing chamber,
The second communication hole is arranged along the axial direction of the inner cylinder on the axial extension line of the liquid guide portion .

According to said structure, the sound which passed through the 1st communicating hole reaches the 1st silencer chamber, and a high frequency region is silenced by the silencer member. By adjusting the amount of the silencing member, the degree of silencing in the high frequency range can be adjusted. And the sound which passed through the 2nd communicating hole located in a line in the axial direction spreads rapidly in the 2nd silence room, and the sound of a low frequency region is silenced. As described above, since the sound in the high frequency range and the low frequency range is appropriately muted, noise is not easily transmitted indoors . In addition, by providing the liquid guide portion in which the first communication hole is not provided, it is possible to prevent the liquid transmitted through the inner cylinder from entering the first silencing chamber and being absorbed by the silencing member.

In the second invention, in the first invention,
The first silencing chamber is disposed on the ventilator side,
The second silencing chamber is configured to be disposed on the ventilation port side.

  In other words, the ventilation duct is normally inclined slightly downward from the ventilator side to the ventilation port side in order to drain the liquid inside, so that if moisture or oil accumulates in the ventilation duct, it will flow to the ventilation port side. It has become. However, according to said structure, since the 2nd muffler room is arrange | positioned rather than the 1st muffler room with a muffler member, the muffler member does not absorb a liquid.

In the third invention, in the first or second invention,
A third silencing chamber is provided between the first silencing chamber and the second silencing chamber;
In the inner cylinder, the first communication hole is disposed in a circumferential direction on the first silencing chamber side of the third silencing chamber, and the first communication hole is not provided on the lower surface side of the third silencing chamber. While the liquid guide portion extends, the second communication hole extends along the axial direction of the inner cylinder on the axial extension line of the liquid guide portion on the second silencing chamber side of the third silencing chamber. .

According to said structure, in a 3rd silencing room, the noise of a medium frequency range can also be reduced by the silencing effect of both the rapid expansion of the space from a 2nd communicating hole, and the sound absorption by a silencing member.

In a fourth invention, in any one of the first to third inventions,
The outer cylinder has an oval cross section,
The second communication hole and the liquid guide portion are arranged along the axial direction of the inner cylinder at a short axis portion located on the lower surface side of the inner cylinder.

  According to said structure, the sound which passed through the 2nd communicating hole spreads at a stretch to the left-right wider space on the long-axis side, and the silencing effect of a low frequency region is effectively exhibited.

As described above, according to the present invention, on the outer periphery of the inner cylinder, the first silencing chamber in which the silencing member is incorporated and the second silencing chamber in which the silencing member is not incorporated are provided side by side in the axial direction. Communicating with the first silencing chamber through one communication hole to send noise from the ventilation port to the silencing member, and communicating with the second silencing chamber through a plurality of second communication holes arranged in the axial direction. Thus, the high frequency range and low frequency range of noise transmitted from the outside to the ventilation duct can be silenced with good balance. In addition, the liquid guide portion in which the first communication hole is not provided can effectively prevent the liquid transmitted through the inner cylinder from entering the first silencing chamber and being absorbed by the silencing member.

It is a bottom view which shows the silencer for ventilation ducts concerning the embodiment of this invention which fractured | ruptured a part of outer cylinder. It is a front view which shows the outline of the ventilation duct system with which the silencer for ventilation ducts was connected. It is a perspective view which shows the silencer for ventilation ducts. It is a perspective view which shows the silencer for ventilation ducts partially broken so that the 1st noise reduction room could be seen. It is a perspective view which shows the lower surface side of an inner cylinder and a partition plate. It is a perspective view which shows the lower surface side of an inner cylinder, a partition plate, and a muffling member. It is a graph which shows the result of a muffling test. FIG. 9 is a view corresponding to FIG. 1 and showing a modification of the embodiment. FIG. 6 is a diagram corresponding to FIG. 5 of a modified example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 shows an outline of a kitchen ventilation system 2 to which a silencer 1 for a ventilation duct according to an embodiment of the present invention is connected. This ventilation system 2 has a ventilation device 3 with a built-in ventilation fan, and the ventilation device 3 and a ventilation port 4 leading to the outside are connected by a circular ventilation duct 5. The ventilation duct 5 is inclined slightly downward from the ventilation device 3 side to the ventilation port 4 side.

  A ventilation duct silencer 1 is connected between the ventilation device 3 and the ventilation opening 4 of the ventilation duct 5.

  As shown in FIGS. 3 to 5, the ventilation duct silencer 1 includes a circular inner cylinder 7 connected to the ventilation duct 5, and an oval shape in which a cross section surrounding the outer side of the inner cylinder 7 in a hermetically sealed manner is symmetrical. (Oval) outer cylinder 8 is provided. The inner cylinder 7 and the outer cylinder 8 are made of cans such as galvanized steel plates and stainless steel plates, for example.

  As shown in FIG. 1, when the inside of the outer cylinder 8 is viewed from the lower surface side, the outer cylinder 8 has a first silencing chamber 10 and a second silencing chamber 11 inside. For example, the first silencing chamber 10 is disposed on the ventilation device 3 side, and is divided into two in the axial direction (longitudinal direction) by the partition plate 12. A silencer member 13 made of water-repellent glass wool, rock wool or the like is built in each divided first silencer chamber 10. It should be noted that by adjusting the material and amount of the silencer member 13, the degree of silence in the high frequency range can be adjusted.

  On the other hand, the second silencing chamber 11 is provided on the ventilation port 4 side in the axial direction in the first silencing chamber 10, and the silencing member 13 is not incorporated.

  As shown in FIG. 5, the inner cylinder 7 includes a plurality of first communication holes 15 that communicate with the first silencing chamber 10 and send noise from the ventilation ports 4 to the silencing member 13. . The first communication hole 15 is provided over most of the circumference of the region corresponding to the first silencing chamber 10, but the liquid guide in which the first communication hole 15 is not provided on the lower surface side of the first silencing chamber 10. A portion 16 is formed. The inner diameter and the number of the first communication holes 15 are not particularly limited, and may be provided in accordance with the size of the silencer 1 for the ventilation duct, the characteristics of the silencer 13, the noise level, and the like.

  On the other hand, a portion of the inner cylinder 7 corresponding to the second silencing chamber 11 is provided with a plurality of second communication holes 17 arranged in the axial direction for communicating with the second silencing chamber 11. These second communication holes 17 are arranged along the axial direction of the inner cylinder 7 at a position corresponding to the short axis portion of the outer cylinder 8 on the lower surface side of the inner cylinder 7 (that is, the lower surface). There is no particular limitation on the inner diameter and the number of the first communication holes 15.

  With this configuration, the noise that has entered from the ventilation port 4 passes through the inner cylinder 7 of the ventilation duct silencer 1 and first reaches the second communication hole 17. Noise spreads in the second silencing chamber 11 through the second communication holes 17 arranged in a narrow axial range located on the lower surface side. At this time, the sound that has passed through the second communication hole 17 spreads into the wide space on the left and right sides of the long axis at a stretch, so that the sound in the low frequency range is muted.

  Further, the noise that has traveled through the inner cylinder 7 passes through the first communication hole 15, reaches the first silencing chamber 10, and is silenced by the silencing member 13.

  As described above, since the sound in the high frequency range and the low frequency range is appropriately muted, it is difficult for noise to be transmitted from the ventilation device 3 to the room.

  Note that the first silencing chamber 10 and the second silencing chamber 11 may not be completely sealed due to gaps in production, but the silencing function is not affected.

  Normally, the ventilation duct 5 is inclined slightly downward from the ventilation device 3 side to the ventilation port 4 side. However, since the liquid guide portion 16 in which the first communication hole 15 is not provided is provided in the first silencing chamber 10, the liquid transmitted through the inner cylinder 7 travels through the liquid guide portion 16 to the second silencing chamber 11 side. To flow. For this reason, the liquid does not enter the first silencing chamber 10 and is not absorbed by the silencing member 13.

  Therefore, according to the silencer 1 for a ventilation duct according to the present embodiment, it is possible to mute the high frequency range and low frequency range of noise transmitted to the ventilation duct 5 from outside with a good balance.

-Example-
For the ventilation duct silencer of the example and the comparative example, an outer cylinder 8 having a length of 500 mm, a short axis 152 and a long axis 272 mm, and an inner cylinder 7 having a diameter of 148 mm are prepared.

(1) Example The width | variety of the liquid guide part 16 was 91 mm, and the 1st communicating hole 15 was provided in the part other than that. The lengths of the two first silencing chambers 10 were each 150 mm, and the silencing members 13 were packed in each.

  Further, the length of the second silencing chamber 11 was 200 mm, the width of the second communication hole 17 was 37 mm, and the second communication hole 17 was not provided in the other portions.

  The ventilation duct silencer 1 configured as described above and similar to the above embodiment was prepared.

(2) Comparative Example The partition plate 12 is not provided in the outer cylinder 8, the first communication hole 15 is provided on the entire surface of the corresponding portion of the inner cylinder 7, and the sound deadening member 13 is packed in the entire outer cylinder 8. A silencer for the ventilation duct was prepared.

(3) Test method The silencer for the ventilation duct of the example or the comparative example connected to the ventilation duct 5 is arranged in the semi-anechoic room, and the side opposite to the ventilation port 4 of the ventilation duct 5 is extended to the reverberation room, so that it is semi-anechoic. We measured how the noise generated in the room changed in the reverberation room after passing through the silencer for the ventilation duct.

(4) Test result The pass criterion was that the muffling effect at 250 Hz, 500 Hz, and 1 kHz was 10 dB or more. In FIG. 7, the greater the insertion loss, the higher the silencing effect.

  As shown in FIG. 7, in the comparative example, the silencing effect at 2 kHz is excessively good, but the acceptance criteria are not satisfied at 250 Hz and 500 Hz.

  On the other hand, in Example, although the silencing effect of 2 kHz was reduced as compared with the comparative example, it was found that the silencing effect of 250 Hz and 500 Hz was improved and all satisfied the acceptance criteria.

-Modification of the embodiment-
8 and 9 show a ventilation duct silencer 101 according to a modification of the embodiment of the present invention, which differs from the above embodiment in that it has a third silencing chamber 20. In addition, in this modification, the same code | symbol is attached | subjected about the same part as FIGS. 1-6, and the detailed description is abbreviate | omitted.

  In the silencer 101 for the ventilation duct according to the present modification, a third silencing chamber 20 that provides a silencing effect on the middle frequency range is provided between the first silencing chamber 10 and the second silencing chamber 11.

  Specifically, in the inner cylinder 107, the first communication hole 15 in the circumferential direction is provided on the first noise reduction chamber 10 side of the third noise reduction chamber 20, similarly to the first communication hole 15 provided in the first noise reduction chamber 10. The liquid guide part 16 without the first communication hole 15 also extends. The second communication hole 17 extends with the same width as the second communication hole 17 provided in the second muffler chamber 11 on the second muffler chamber 11 side of the third muffler chamber 20 in the inner cylinder 107.

    In addition, the silencing member 13 is disposed in almost the entire first silencing chamber 10 and the third silencing chamber 20.

By comprising in this way, in the 1st silence room 10 and the 2nd silence room 11, the effect similar to the said embodiment is acquired. Further, in the third silencing chamber 20, the noise in the middle frequency range can be reduced by the silencing effect of both the rapid expansion of the space from the second communication hole 17 and the sound absorption by the silencing member 13.

(Other embodiments)
The present invention may be configured as follows with respect to the above embodiment.

  That is, in the said embodiment, although the 1st silencer room 10 side was arrange | positioned at the ventilator 3 side, you may arrange | position the 2nd silencer room 11 side at the ventilator 3 side. However, in consideration of liquid discharge, it is preferable to arrange the first silencing chamber 10 side on the ventilation device 3 side as in the above embodiment. In addition, although the example which provides the ventilation apparatus 3 which ventilates forcibly indoors was shown in the said embodiment, this invention is applicable also when there is no ventilation apparatus 3 and only ventilates.

  Moreover, in the said embodiment, although the 2nd communicating hole 17 was arrange | positioned in the 2nd muffling chamber 11 in the lower surface side of the inner cylinders 7 and 107, you may arrange | position on the upper surface side or an upper surface side and a lower surface side.

  In the above embodiment, the cross-sectional shape of the outer cylinder 8 is an oval type (oval shape), but may be an oval shape. Further, although it may be circular, an oval type is desirable in view of the effect of rapid expansion of the space from the first communication hole 15.

  In the above embodiment, the interior of the first silencer chamber 10 is partitioned by one partition plate 12, but may be partitioned by two or more partition plates 12, and may not be partitioned by the partition plate 12.

  Furthermore, in the said embodiment, although the silencer 1,101 for ventilation ducts was provided in the ventilation system 2 of the kitchen, it is not limited to this, You may provide in ventilation systems, such as a toilet, a bedroom, a bath.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or a use.

  As described above, the present invention is useful for a silencer for a ventilation duct used in a kitchen ventilation system or the like.

DESCRIPTION OF SYMBOLS 1 Silencer for ventilation duct 2 Ventilation system 3 Ventilator 4 Ventilation opening 5 Ventilation duct 7 Inner cylinder 8 Outer cylinder 10 1st silencer room 11 2nd silencer room 12 Partition plate 13 Silencer member 15 1st communicating hole 16 Liquid guide part 17th Two communication holes 20 Third silencer chamber 101 Silencer 107 for ventilation duct Inner cylinder

Claims (4)

An inner cylinder connected to a ventilation duct that communicates between the ventilator and the vent, leading from indoor to outdoor;
A silencer for a ventilation duct provided with an outer cylinder that encloses the outside of the inner cylinder in a sealed manner,
The outer cylinder includes a first silencing chamber in which a silencing member is incorporated, and a second silencing chamber that is provided in the first silencing chamber in an axial direction and does not incorporate the silencing member.
The inner cylinder is
A plurality of first communication holes for communicating between the first silencing chamber and sending noise from the ventilation port to the silencing member;
Have a plurality of second communication holes aligned in the axial direction that communicates between the second silencing chamber,
A liquid guide portion not provided with the first communication hole is formed on the lower surface side of the first silencing chamber,
The silencer for a ventilation duct , wherein the second communication hole is arranged along the axial direction of the inner cylinder on an axial extension line of the liquid guide portion . The silencer for a ventilation duct according to claim 1 ,
The first silencing chamber is disposed on the ventilator side,
The silencer for a ventilation duct, wherein the second silencer chamber is configured to be disposed on the ventilation port side. In the silencer for ventilation ducts according to claim 1 or 2,
A third silencing chamber is provided between the first silencing chamber and the second silencing chamber;
In the inner cylinder, the first communication hole is disposed in a circumferential direction on the first silencing chamber side of the third silencing chamber, and the first communication hole is not provided on the lower surface side of the third silencing chamber. While the liquid guide portion extends, the second communication hole extends along the axial direction of the inner cylinder on the axial extension line of the liquid guide portion on the second silencing chamber side of the third silencing chamber.
Silencer for ventilation ducts. In the silencer for ventilation ducts according to any one of claims 1 to 3,
The outer cylinder has an oval cross section,
The ventilation duct silencer, wherein the second communication hole and the liquid guide portion are arranged along a short axis portion located on a lower surface side of the inner cylinder along an axial direction of the inner cylinder.

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