JP2911510B2 - Silencer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a silencer, and more particularly to a silencer suitable for installation in a ventilation opening of a house, a factory or other buildings, or a duct of a blower or an exhaust fan. .

(PRIOR ART) Many of the proposals used or proposed as silencers for natural ventilation installed in ventilation openings of buildings,
While attaching a sound insulating material to the inner peripheral surface of the housing having the gas inlet and the gas outlet, a baffle plate is disposed inside the housing (for example, Japanese Patent Laid-Open No. 57-23737), For example, means for rapid enlargement or rapid reduction are provided (for example, Japanese Patent Application Laid-Open No. 58-156136).

(Problems to be Solved by the Invention) The above-mentioned sound deadening device utilizes the sound deadening or sound insulating effect of the sound insulating material and the energy loss of the sound wave due to the direction change of the flow path or the sudden change in the flow path area. The former effect decreases as the amount of air passing through the housing increases, and in the latter, the higher the air amount,
Since the energy of the entire sound wave increases, the transmitted sound eventually increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a silencing device capable of silencing or isolating sound without being essentially affected by the sound insulating effect of the sound insulating material or the energy loss of sound waves due to a change in direction of the flow path or a sudden change in the area of the flow path.

Another object of the present invention is to provide a noise reduction device in which the noise reduction or sound insulation effect is not substantially affected even when the amount of gas passing through the housing increases.

(Means for Solving the Problems, Functions, and Effects) The present invention is a device that silences gas introduced from an inlet into an outlet. This silencer comprises a hollow housing having an inlet and an outlet for the gas, and a partitioning means provided inside the housing, wherein the partitioning means is orthogonal to the axis of the inlet and has a square planar shape. A flat plate consisting of two sides, said two opposite sides of said plate being attached to said housing, said passage being formed between each of the remaining two opposite sides and said housing. A plate material is disposed, a flow of gas flowing from the inlet is separated into two flows in the plate material, which flow in opposite directions, and the separated two flows are opposed to each other via the passage. And separating means for separating a part of each of the two opposing flows into two flows facing in opposite directions.

If the silencer is installed in a building vent, air outside the building is directed through the housing inlet into the interior of the housing. The air that has entered the interior of the housing is divided into two flows directed in opposite directions by the partitioning means. The two flows then reverse direction and become opposing flows. A part of the opposing flows becomes two flows directed in opposite directions by the separating means. afterwards,
Gas exits the outlet. If the silencer is installed in a duct, air, smoke and other gases will be channeled from the inlet of the housing, but the effect will be the same.

The air entering from the inlet becomes two flows directed in opposite directions by the partitioning means, and thereafter, the two flows become flows opposed to each other. The flow generates a standing wave having a phase opposite to that of the standing wave, and both the standing waves act so as to cancel each other. Even if a plurality of sounds having different properties enter the inlet, the two separated flows contain sounds of the respective properties, and are canceled by the opposing faces as described above. In this way, a silencing effect is obtained.

Since a part of each of the two flows facing each other after passing through the partitioning means flows in the separating means in opposite directions to each other, it is possible to expect noise reduction due to a change in direction. In addition, after passing through the separating means, the flow from the other separating means is opposed to each other, so that a noise canceling effect can be obtained by the action of canceling the standing wave of the opposed flow.

Since the noise reduction or sound insulation is performed exclusively depending on the physical properties of the sound waves, the noise reduction effect does not vary depending on the amount of gas passing through the housing. By changing the length of the housing, the frequency to be silenced can be arbitrarily selected.

Because the flat plate of the partitioning means is orthogonal to the axis of the inlet,
Two oppositely directed flows can easily be obtained. Further, by mounting the two opposing sides of the flat plate material to the housing, the mounting of the partition means and the formation of the passage can be performed at the same time, so that the production is simple.

The housing and the partitioning means are preferably formed such that the two opposing flows are orthogonal to the flow direction and symmetric with respect to a virtual plane including the axis of the inlet.

Since the housing and the partitioning means are structurally symmetrical, it is possible to easily generate a standing wave that cancels out the sound waves contained in the two opposing flows.

It is preferable to attach a sound insulating material to the inner peripheral surface of the housing and the outer peripheral surface of the partition means.

Thus, in addition to the sound extinction or sound insulation due to the physical phenomenon described above, a reduction in the sound pressure level due to the sound insulation material can be expected.

The direction of the outlet is perpendicular to the axis of the inlet,
It can be arranged so as to extend in a direction oblique to the axis of the inflow port in addition to the parallel direction. When the axes of the outlets are orthogonal to each other, it is particularly convenient as a silencer attached to a ventilation hole of a building, and when they are parallel, it is convenient as a silencer attached to a duct.

(Embodiment) As shown in FIG. 1, a silencer 8 controls the flow of air or other gas flowing in the direction A from an inlet 12 of a housing 10 by partitioning means 16 in directions B ₁ and B opposite to each other. _{2. The} two flows are separated into two flows directed to the second direction, and then the two separated flows are made to flow in the opposite directions C ₁ and C _2, and are combined while flowing out from the outlet 14 of the housing 10 in the D direction. Is what you do.

In the embodiment shown in FIGS. 2 and 3, the silencer comprises a housing 10 and partitioning means 16 and a ventilation opening 18 of the building.
It is configured to be attached to.

The housing 10 is formed entirely in a rectangular parallelepiped shape by a plate member 20, and is provided with a square hole and a circular hole. The former hole becomes the inflow port 12 as it is, and a cylindrical tubular member 21 is aligned and attached to the latter hole, and the outflow port 14 is formed. The outlet 14 is positioned such that its axis L ₂ is orthogonal to the axis L ₁ which is the center line of the inlet 12. Glass wool 22 is adhered to the inner peripheral surfaces of the plate member 20 and the tube member 21.

The partitioning means 16 is made of a flat plate 17 and is arranged to be orthogonal to the axis L ₁ of the inlet 12. The plate 17 has a rectangular planar shape, and its long side is, as shown in FIG.
A passage 24 is formed between the shorter side of the housing 10 and the opposite plate of the housing 10. Glass wool 22 is attached to plate 17.

Partition means 16, two passages 24 which can be on both sides of, so as to be located symmetrically with respect to a virtual plane P which is perpendicular to the axis L ₁ of the inlet 12 contain and to the plane of FIG. 2, is attached to the housing 10. With this configuration, the two flows flowing from the inflow port 12 and facing in the opposite directions, and thereafter, the two flows facing each other can be made symmetric with respect to the virtual plane P,
The interference of the sound waves contained in the two opposing flows can be reliably generated.

In the embodiment shown, a separating means 30 is provided before the outlet 14. The separating means 30 separates a part of each of the two flows facing the directions C ₁ and C ₂ facing each other by the partitioning means 16 into flows facing the opposite directions E ₁ and E ₂ . The separation means 30 includes a plate 31 and a glass wool 22 attached to the plate 31.

The housing 10 has a packing 32
The outlet 14 is inserted into the ventilation port 18 of the building 34 with the intervening member, and the screw 38 is screwed into the curl plug 36 to be attached to the building 34. The outflow port 14 is provided with a well-known gully 40.

FIG. 4 shows a commercially available silencer 70. This silencer 70 is for a ventilation opening of a building, and comprises a cylindrical housing 72 and a cap 74 lined with glass wool and attached to the housing 72. Inlet 76 in the lower half of the end covered by cap 74 of housing 72
Is provided.

The air entering from the inlet 76 is guided through the gap 78 into the housing 72 and enters the building 80.

The silencing device shown in FIGS. 2 and 3 and the commercially available silencing device shown in FIG. 4 were examined for sound insulation performance according to JIS A 1416 “Method of measuring sound transmission loss in a laboratory”.
Hermeticity was examined by JIS A 4706 "Sash made of steel and aluminum alloy".

It is said that the frequency of sound waves generated by traveling of many vehicles among the sound waves entering a building is about 250 Hz. Of the results obtained from the experiment, 200, 250,
Comparing the sound insulation performance at 315 and 400 Hz, the sound insulation of 24, 27, 24, and 26 dB, respectively, was achieved in the configuration according to the present invention. In contrast, in the case of FIG. 4, they were 25, 16, 16, and 23 dB, respectively.

On the other hand, the pressure difference between the inlet and outlet of the silencer is 0.5,1,3,
The ventilation rate at 5 kg / m is 23.81, 34.57, 59.15, 82.19 m / h, respectively, in the configuration according to the present invention.
Met. On the other hand, in the case of FIG.
They were 9.94, 56.08, 99.86 and 122.91 m / h.

From the above results, it can be seen that the sound insulation device configured according to the present invention has better sound insulation performance than a commercially available one and can secure an appropriate ventilation volume.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the principle of a sound insulation device according to the present invention, FIG. 2 is a longitudinal sectional view of the sound insulation device, FIG. 3 is a sectional view taken along line 3-3 in FIG. The figure is a longitudinal sectional view of a commercially available sound insulation device similar to the sound insulation device according to the present invention. 8: Sound insulation device, 10: Housing, 12: Inlet, 14: Outlet, 1
6: partition means, 22: glass wool.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F24F 13 / 00,13 / 02 F01N 1/02-1/24

Claims (5)

(57) [Claims] 1. A device for silencing a gas flowing from an inlet into an outlet, the hollow housing having an inlet and an outlet for the gas, and a partitioning means provided inside the housing. A flat plate made of four sides perpendicular to the axis of the inlet and having a rectangular planar shape, and two opposite sides of the plate are attached to the housing, and the remaining opposing sides are provided. The plate is arranged so that a passage is formed between each of the two sides and the housing, and the flow of gas flowing from the inflow port is converted into two flows in the plate in opposite directions. A partitioning means for separating and separating the two flows into flows facing each other via the passage; and separating a part of each of the two flows facing each other into two flows facing in opposite directions. That includes a separation unit, silencer. 2. The housing and the partitioning means are formed so that the two opposing flows are orthogonal to the flow direction and symmetric with respect to an imaginary plane including the axis of the inflow port. The noise reduction device according to claim 1. 3. The noise reduction device according to claim 1, wherein a sound insulating material is attached to an inner peripheral surface of the housing and an outer peripheral surface of the partitioning means. 4. The muffler according to claim 1, wherein the outlet has an axis extending in a direction perpendicular to the axis of the inlet. 5. The muffler according to claim 1, wherein the outlet has an axis extending in a direction parallel to the axis of the inlet.