JPH03217615A - Silencer - Google Patents

Abstract

PURPOSE:To silence or insulate sound without energy loss of a sound wave by separating the flow of inflow gas into two flows mutually in the reverse directions, hereafter providing a partition means inside a housing to make opposite flows. CONSTITUTION:In a silencer 8, inflow air and the like flowing in the A direction from the inflow port 12 of a housing 10 is separated into two flows mutually in the reverse directions B1, B2 by a partition means 16, and hereafter two separated flows are changed into the flows in the opposite directions C1, C2. During they are joined and flow out from the outflow port 14 in the D direction, sound is silenced. In this way, silencing effect is invariable regardless of the gas quantity passing through the housing 10, because silencing or insulating of sound exclusively depends on the physical property of a sound wave. Further, by changing the length of the housing 10, frequency of silencing object can be optionally selected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a silencing device, and particularly to a silencing device suitable for installation in the ventilation openings of houses, factories, and other buildings, as well as in the ducts of blowers or exhaust fans. .

(Prior Art) Most of the noise damping devices used or proposed for natural ventilation installed in the ventilation holes of buildings include a sound insulating material on the inner circumferential surface of a housing having a gas inlet and an outlet. At the same time, a baffle plate may be placed inside the housing (for example, Japanese Patent Laid-Open No. 57-237
3 No. 7), or provide a means for rapidly expanding or decreasing the flow path area (for example, Japanese Patent Application Laid-Open No. 1983-1999).
156136).

(Problems to be Solved by the Invention) The above-described sound damping device utilizes the sound damping or sound insulation effect of the sound insulating material and the energy loss of sound waves caused by changing the direction of the flow path or by sudden changes in the surface of the flow path. The effect of the former decreases as the amount of air passing through the housing increases, and in the latter, as the amount of air increases, the overall energy of the sound wave increases, so the transmitted sound eventually decreases.
It gets bigger.

An object of the present invention is to provide a sound damping device that can muffle or insulate sound essentially without depending on the sound insulation effect of a sound insulation material or the energy loss of sound waves due to a change in direction of a flow path or a sudden change in the area of a flow path.

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

(Means, Actions, and Effects for Solving the Problems) A silencer according to the present invention includes a hollow housing having a gas inlet and an outlet, and a partition means provided inside the housing, the inlet and the gas inlet. partitioning means for separating the flow of gas flowing in from the flow into two flows oriented in opposite directions, and for making the two separated flows into opposing flows.The two opposing flows merge to form the flow. flows out from the exit.

When installed in a silencer or building vent, air outside the building is directed into the interior of the house sink through the inlet in the housing. The air entering the interior of the housing is divided into two streams directed in opposite directions by the partitioning means, and the two streams then reverse direction to become mutually opposing streams, merge and exit from the outlet. If the silencer is installed in a duct, air, smoke or other gases are directed through the inlet of the housing, but the effect is the same.

The air entering from one inlet becomes two flows directed in opposite directions by the partitioning means, and then the two flows become opposite flows, so that one flow creates an apparent standing wave. Then, another flow generates a standing wave that has an opposite phase to the standing wave, and both standing waves act to cancel each other out. Even if a plurality of sounds with different properties enter the inlet, the two separated flows contain the sounds of each property, and by opposing each other, they cancel each other out as described above. In this way, a silencing effect is obtained.

Since silencing or sound insulation depends solely on the physical properties of sound waves, the silencing 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 muted can be arbitrarily selected.

According to a preferred embodiment, the partitioning means consists of a flat plate;
It is arranged perpendicularly to the axis of the inlet.

If the plate is perpendicular to the axis of the inlet, two mutually opposite flows can easily be obtained.

so that the two opposing flows are perpendicular to these flow directions and symmetrical with respect to a virtual plane containing the axis of the inlet,
Preferably, the housing and the partition means are formed.

In order to amplify the sound waves contained in each of the two opposing flows and generate a standing wave, it is sufficient to make the housing and the partition means structurally symmetrical, and this is the simplest method.

If a sound insulating material is attached to the inner circumferential surface of the house sink and the outer circumferential surface of the partitioning means, in addition to noise reduction or sound insulation due to the above-mentioned physical phenomenon, a reduction in the sound pressure level due to the sound insulating material can be expected.

The outflow port can be arranged such that its axis extends in a direction perpendicular to, parallel to, or oblique to the axis of the inflow port. When the axes of the outlet are perpendicular to each other, it is particularly convenient as a silencer to be attached to a ventilation hole in a building, and when they are parallel to each other, it is convenient as a silencer to be attached to a tactile system.

In another embodiment of the invention, means are provided for separating each of the two opposing streams into two streams directed in opposite directions.

(Example) As shown in FIG. 1, the silencer 8 is configured to divert the flow of air and other gases flowing in the direction A from the inlet 12 of the housing 10 into opposite directions B, , , , and
Separates into two streams directed to B2, then separated 2
The two flows are made to flow in opposite directions C, , C, and the sound is muffled while they are merged and flowed out from the outlet 14 of the housing 10 in the direction D.

In the embodiment shown in FIGS. 2 and 3, the silencer comprises a housing 10 and partition means 16, and is adapted to be installed in a ventilation opening 18 of a building.

The housing 10 is formed entirely in the shape of a rectangular parallelepiped using a plate material 20, and is provided with a square hole and a circular hole. The former hole directly serves as the inlet 12, and a cylindrical tube member 21 is aligned and attached to the latter hole to form the outlet 14.

The outflow port 14 is located such that its axis L2 is perpendicular to the axis L1, which is the centerline of the inflow port 12.

Glass wool 22 is attached to the inner peripheral surfaces of the plate material 20 and the cylinder material 21.

The partition means 16 is made of a flat plate member 17, and is arranged perpendicularly to the axis L1 of the inlet 12. The plate material 17 has a rectangular planar shape, and its long side is attached to the opposing plate material of the housing 10, as shown in FIG.
A passage 24 is formed between the short side and the opposing plate of the housing 10. Glass wool 22 is plate material 17
It is attached to.

The partition means 16 has two passages 24 formed on both sides thereof.
It is attached to the house sink 10 so as to be located symmetrically with respect to a virtual plane P that includes the axis L1 of the inlet 12 and is orthogonal to the paper plane of FIG.

If formed in this way, the two flows flowing in from the inlet 12, facing in opposite directions, and then facing each other can be made symmetrical with respect to the virtual plane P, and the sound waves contained in each of the two opposing flows can be made symmetrical with respect to the virtual plane P. interference can be ensured.

In the illustrated embodiment, a separation stage 30 is provided upstream of the outlet 14. The separation means 30 separates the two flows directed in opposing directions C1 and C2 by the partition means 16 into flows directed in mutually opposite directions E and E2. The separating means 30 consists of a plate material 31 and a class wool 22 attached to the plate material 31.

The housing 10 has the inlet 12 facing downward, and the outlet 14 is connected to the ventilation opening 1 of the building 34 with the packing 32 interposed therebetween.
8 and screws 38 into the curl plug 36 to attach it to the building 34. A collar 40, which is known per se, is attached to the outlet 14.

In the embodiment shown in FIG. 4, the silencer 50 consists of a housing 52 and a partition 54, and is incorporated into a duct 56 for forced ventilation. In this muffler 50, an inlet 58 and an outlet 60 are formed in a cylindrical shape, each of which is flanged to the duct 56, so that the axis L3 of the outlet 60 is an extension of the axis L1 of the inlet 58. To position.

The gas entering the housing 52 from the inlet 58 in the A direction is divided into two flows in opposite directions B, B2 by the partition 54, and then reversed and flows in opposite directions. The flows flow toward C1 and C2, merge, and flow out from the outlet 60 in the F direction. In this way, although the outflow direction is different from the above embodiment, the housing 52 is
Outflow of the house sink 10 of the embodiment [change the position of I,
The other parts can be constructed in the same manner, and the partitioning means 54 can be constructed in the same manner as the partitioning means 16.

What is shown in FIG. 5 is a commercially available muffling device 70. This muffling device 70 is for use in a ventilation opening of a building, and consists of a cylindrical housing 72 and a cap 74 lined with glass wool and attached to the housing 72. An inlet 76 is provided in the lower half of the end of the housing 72 covered by the cap 74 .

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

The sound insulation performance of the sound damping devices shown in FIGS. 2 and 3 and the commercially available sound damping device shown in FIG. The airtight performance was investigated using ``steel and aluminum alloy sashes''.

Among the sound waves that enter buildings, the frequency of the sound waves generated by running vehicles, which is particularly common, is said to be around 250 Hz. Of the results obtained from the above experiment, 200
, 250, 315, and 400 Hz, those configured according to the present invention achieved sound reduction of 24, 27, 24, and 26 dB, respectively.

On the other hand, in the case of Fig. 5, 25, 16, and
It became 16.23dB.

On the other hand, the pressure difference between the population of the silencer and the outlet is 0.5,
1, 3. The ventilation amount when it is 5 kg/m2 is
For those constructed in accordance with the present invention, each 23.8
1, 34.57, 59.15, 82.19m
It was 3/h.

On the other hand, in the case of Fig. 5, each 39.945
6.08, 99.86, 122.91m3/h
Met.

From the above results, it can be seen that in the silencer configured according to the present invention,
It can be seen that it has superior sound deadening performance compared to commercially available products and can secure an appropriate amount of ventilation.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the principle of the muffler according to the present invention, Fig. 2 is a vertical cross-sectional view of the muffler, Fig. 3 is a cross-sectional view taken along line 3-3 in Fig. 2, and Fig. The figure is a longitudinal sectional view of another embodiment of the silencer, and FIG. 5 is a longitudinal sectional view of a commercially available silencer similar to the silencer according to the invention. 8, 50: Silencer, 10, 52: Housing, 12, 58 inlet, 14, 60: Outlet, 16, 54: Partition means, 22: Glass wool.

Claims (7)

[Claims] (1) A hollow housing having a gas inlet and an outlet, and a partitioning means provided inside the housing, which separates the flow of gas flowing from the inlet into two flows directed in opposite directions. A silencing device comprising a partitioning means for separating the two separated flows into opposing flows, wherein the two opposing flows merge and flow out from the outlet. (2) The muffling device according to claim 1, wherein the partition means is made of a flat plate and is arranged perpendicular to the axis of the inlet. (3) The housing and the partition means are formed so that the two opposing flows are perpendicular to these flow directions and symmetrical with respect to a virtual plane that includes the axis of the inlet. The silencer according to (2). (4) The silencer according to claim (1), wherein a sound insulating material is attached to the inner circumferential surface of the housing and the outer circumferential surface of the partitioning means. (5) The muffler according to claim 1, wherein the axis of the outlet extends in a direction perpendicular to the axis of the inlet. (6) The muffling device according to claim 1, wherein the outflow port has an axis extending in a direction parallel to the axis of the inflow port. (7) A hollow housing having a gas inlet and an outlet, and a partitioning means provided inside the housing, which separates the flow of gas flowing from the inlet into two flows directed in opposite directions. a partitioning means for separating the two separated flows into opposing flows; and a means for separating each of the two opposing flows into two flows directed in opposite directions; A silencing device in which the flows merge and flow out from the outlet.