WO2018188762A1

WO2018188762A1 - Splitter sound attenuator assembly comprising sound-absorbing end faces

Info

Publication number: WO2018188762A1
Application number: PCT/EP2017/059054
Authority: WO
Inventors: Wolfgang Herget; Peter BRANDSTÄTT; Thomas Fuchs
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V.; Siegle + Epple GmbH & Co. KG
Priority date: 2017-04-14
Filing date: 2017-04-14
Publication date: 2018-10-18
Also published as: CN110770511A; EP3610205A1

Abstract

The invention relates to: a sound attenuator assembly comprising a housing (1) having a wall structure of any design, the housing containing a sound source (11); a conduit system (3, 4) for conveying a medium into the surroundings; and a splitter sound attenuator which is integrated into the conduit system (3, 4) and which has a series of parallel splitter sound attenuator housings (6), wherein air gaps (10) through which the medium can flow are located between the splitter sound attenuator housings (6). The sound attenuator assembly is characterised in that a sound absorber, in particular a microperforated absorber (7), is mounted on the end faces of the splitter sound attenuator housings facing the sound source (11), or a microperforated absorber (7.6) is inserted between splitter sound attenuator housing portions (5.1, 5.2) arranged adjacently in the flow direction.

Description

Slotted silencer arrangement with sound-absorbing end faces

The invention relates to a silencer arrangement according to the preamble of claim 1.

A variety of technical devices are incorporated into their enclosures or enclosures for their operation. These housing or piping systems can serve several purposes, such as the protection of the equipment from external impact, the shielding of persons and the environment from hazards by the devices, the transport of media, if the housing is also part of a delivery line, or the limitation of the acoustic emission of the devices in the environment.

From US 5,473,124 A a slotted silencer assembly is known, are perforated in the side walls of the muffler.

From DE 37 07 650 C1 a slotted silencer is known in which phase-rotating resonators are used in the flow profiles. From DE 297 10 491 U1 slotted silencers are known which use the effect of sound attenuation by micro perforation.

From WO 2009/1 10843 A1 a slotted silencer with curved flow profiles is known.

From US 2,916,101 A a slotted silencer with a round flow profile is known. The inflow profile can be acoustically transparent and surround a space that is filled with acoustically damping material.

The present invention serves to effectively reduce the sound radiation of a noise source built into a housing or piping system into the environment in a selected acoustic frequency range. It is assumed that the noise source built into the housing is connected to the environment via a piping system and this piping system is used for the transport of media. The radiation of sound energy to the environment is then on the one hand directly as sound transmission through the housing walls and on the other hand as sound propagation along the line system to the outside. The radiated sound energy is dependent on the sound power of the sound source, the acoustic absorption property of the housing inner surfaces, the Dämmgüte the housing walls, the structure-borne sound of the pipe system and the sound-absorbing effect of the pipe system.

The measures to reduce the noise emission into the environment therefore set at the following points:

the reduction of the source noise level, the reduction of the noise level within the housing by increasing the absorption of space on the housing inner surfaces or by absorption measures within the housing volume,

the improvement of the acoustic insulation effect of the housing walls,

- The acoustic decoupling of the pipe system from the housing of the sound source and

- the installation of sound attenuations in the cable path for noise level reduction along the line.

The state of the art includes the following arrangements:

- Housing walls of non-metallic, solid, porous or layered materials,

- Housing walls made of single-shell or multi-shell metal structures,

multi-skin walls with or without acoustically effective filling of the air gap,

- execution of the housing inner walls with reverberant bare metal surfaces,

Planking of the housing inner walls with absorbent materials of different thickness,

- equipment of the housing interior with acoustically absorbing materials,

- Arrangement of structure-borne sound decoupling elements between the housing and

Line elements for reducing the longitudinal sound line in the line system,

- Arrangement of silencer elements in the pipe system as a pipe silencer or slotted silencer such that the fluid can flow as undisturbed as possible, Arrangement of porous absorbers with and without fibrous materials,

Arrangement of plate resonators and

Arrangement of microperforated absorbers as freely positioned planar elements or of microperforated absorbers with a tuned downstream airspace with or without damping.

The object of the invention is to provide a muffler assembly according to the preamble of claim 1, which advantageously combines the effect of the acoustic sound absorption within the housing with the action of a slotted silencer.

This object is achieved with the muffler assembly according to claim 1.

According to further embodiments of the invention, which are set forth in dependent claims, the microperforated walls can be advantageously arranged in different ways.

According to the invention, a silencer arrangement is provided with a housing of arbitrary wall structure which contains a sound source, and a duct system for conveying a medium, and a slotted silencer which is installed in the duct system and which has a series of parallel slotted silencer casings, air gaps being arranged between the slotted silencer casings, through which the medium can flow.

This silencer arrangement is characterized in that a sound absorber, in particular a microperforated absorber, is placed on the end faces of the slotted silencer housings facing the sound source, or a sound absorber, in particular a microperforated absorber, is inserted between adjacent slotted silencer housing parts in the flow direction. This reduces the sound level in the area of the housing in which the sound source is located. This aspect is commonly attributed no importance, since only care is taken that in the flowing medium, as it were mitströmender sound is attenuated. By a silencer on the front sides, also upstream sides, of course, this flowing sound is attenuated in the medium, but this effect is subordinate. Primarily, the sound level in the area of the housing where the sound source is located is attenuated. Thus, a sound radiation from this area is reduced in the environment in a simple manner. This is surprising inasmuch as so far has been placed mainly on an improved sound insulation and / or sound attenuation in the housing wall.

The invention basically works with any sound absorber. The invention works particularly well from a current point of view but with a microperforated absorber. In this respect, the focus is always on a micro-perforated absorber.

It should also be made clear that the effect according to the invention, namely the sound reduction in the housing, is not well achieved by means of each absorber with an absorber on the front side. It is important that the additional absorber on the end faces directly adjacent to the area of the housing in which the silencer is located. However, this is not the case in US Pat. No. 2,916,101 A, which was found in a search conducted with the invention in the knowledge. The sound-absorbing running on the upstream sides of US 2,916,101 A serve only the improved sound attenuation of the flowing medium.

In one embodiment, the microperforation and the width and the depth of the absorber are chosen such that an absorption in a desired frequency Spectrum takes place. It is clear that there is no complete absorption and the frequency range can not be set arbitrarily accurate. However, it is possible to design the absorber independently of the sound source and of the desired attenuation.

In one embodiment, the absorber has a microperforated wall oriented to the sound source. In this way, a classic micro-perforated absorber is formed, which reduces the amount of sound in the cavity of the housing, ie in the region of the housing in which the sound source is located.

In one embodiment, the absorber has a microperforated wall oriented in the direction of the air gaps. Thus, the sound content in the flowing medium can be damped.

In one embodiment, the absorber has two or more microperforated walls oriented in two or more directions. This can be achieved in different directions attenuation.

In one embodiment, the absorber has a curved microperforated wall oriented to the sound source. A curved wall offers the particular advantage that a round, flow dynamic favorable inflow is formed. In addition, the curvature causes a broadband effect of the tuned resonator, since the curvature no uniform depth of the absorber volume is present.

In one embodiment, the absorber is subdivided in the direction of its largest dimension by one or more separating elements into sub-volumes. This may be advantageous from the acoustic effect, since the absorbing effect increases in the desired frequency range. Furthermore, this can offer design advantages.

In one embodiment, the absorber has an additional rear wall. While in many embodiments as a rear wall the - missing the absorber - the sound source facing wall is used as a rear wall, also an additional rear wall can be used. This achieves independence from the already existing wall.

In one embodiment, the absorber interposed between adjacent slotted damper housing parts has one or two microperforated walls oriented toward the air gap (s). Thus, the effect of the slotted silencer can be strengthened.

The invention also relates to a slotted silencer for use in a silencer arrangement described above, wherein on the upstream side of the slotted silencer a hollow body with microperforations can be placed or placed.

The invention will now be explained in more detail with reference to exemplary embodiments. Show it:

1 is a silencer assembly of a housing, a conduit for a flowing medium and a built-in to the housing in the line path backdrop silencer with patch micro-perforated absorbers, 2 shows an exploded view of a part of a silencer arrangement with a part of a slotted silencer, a microperforated absorber housing and an absorber rear wall

3 different forms of the muffler assembly according to the

Invention:

3a shows a side view of a Kulissendämpferteils with attached absorber, the perforation surface is oriented to the sound source,

3b is a side view of a Kulissendämpferteils with attached absorber, the perforation surface is oriented in the direction of the muffler gap,

3c is a side view of a Kulissendämpferteils with attached absorber whose two perforation surfaces are oriented twice in the direction of the silencer column,

3d shows a side view of a Kulissendämpferteils with attached absorber whose three perforation surfaces are oriented in three different directions,

3e is a side view of a Kulissendämpferteils with attached absorber, the perforation surface is curved,

Fig. 3f is a side view of a Kulissendämpferteils, which is divided into two sections, between which an absorber is inserted, the two perforation faces are oriented in the direction of the muffler. Fig. 1 shows the overall system of the muffler assembly, comprising a box-shaped housing 1 with an enclosed space 2, with a arranged on the right side of the housing wall opening 3, to which a portion of a conduction path may adjoin, and arranged on the left side of the housing wall openings 4 of the conduction path includes. The muffler assembly further comprises arranged on the left housing inner wall slotted silencer 5 in absorber, resonator or mixed construction and on housing 6 of the slotted silencer 5 patch micro-perforated absorber 7. The latter each have a perforated front wall 9 and may have a rear wall 8. Between the slotted silencers 5 are air gaps 10. In the housing 1, a noise source 1 1 is placed centrally with or without conveying function.

Generally, it is a silencer assembly with a housing 1 any wall structure containing a sound source 1 1. It is connected to a line system 3, 4 for conveying a medium into the environment. It has a pipe or slotted silencer which is installed in the vicinity of the housing 1 in the conduit system 3, 4 and which has a series concentric or parallel pipe or bushing damper housing 6 with air gaps 10 between the pipe or slotted silencer housings 6. On the sound source 1 1 facing end faces of the pipe or slotted silencer housing 6 micro-perforated absorber 7 are placed or it is inserted between pipe or slotted silencer housing parts 5.1, 5.2 a micro-perforated absorber 7.6.

The sound radiation of the noise source 1 1 in the conduction path is lowered through the perforated front walls 9 of the absorber 7 in a defined acoustic frequency range. The absorption frequency can be tuned specifically to disturbing frequencies in the source spectrum, so that a tailor-made sound reduction can be achieved within the housing 1. The level-lowering effect is not constant; the highest level-lowering effect occurs in the vicinity of the absorber. The positioning of the absorber 7 on the front side of the silencer scenes 5 has the advantage that the highest absorption effect takes place directly at the entrance of the slotted silencer 5. As a result, the effectiveness of the level reduction is optimized along the running over the wall openings 4 line path.

Fig. 2 shows the structure of the noise damping arrangement, which consists of a part of a slotted silencer 5 with a housing 6 and an absorber 7, which has a housing with a microperforated front wall 9. The absorber housing can be provided with an absorber rear wall 8. The absorber housing can furthermore be subdivided with one or more separating elements 12. The absorber 7 is placed and fixed on the housing 6.

Fig. 3 shows various embodiments of mounted on backdrop silencers 5 absorbers. The absorbers have different orientations of the microperforated walls pointing in different directions or different basic shapes.

FIG. 3a shows a possible embodiment in which a microperforated wall 9.1 of an absorber 7.1 points in the direction of the sound source 11.

FIG. 3 b shows a possible embodiment in which a microperforated wall 9. 2 of an absorber 7. 2 points in the direction of the air gaps 10.

FIG. 3 c shows a possible embodiment in which two microperforated walls 9. 2, 9. 3 of an absorber 7. 3 point in the direction of the air gaps 10.

3d shows a possible embodiment in which three microperforated walls 9.2, 9.3, 9.4 of an absorber 7.4 are oriented in three different directions. 3e shows a possible embodiment in which a microperforated wall 9.5 of an absorber 7.5 is curved.

3f shows a possible embodiment in which the slotted silencer is subdivided into two parts 5.1, 5.2 and an absorber 7.5 is inserted between these parts, wherein two microperforated walls 9.2, 9.3 of the absorber 7.5 are oriented in the direction of the air gaps 10.

Claims

1 . Silencer assembly comprising a housing (1) of any wall structure containing a sound source (1 1) and a conduit system (3, 4) for conveying a medium, and a slotted silencer, which is installed in the duct system (3, 4) and the one Series parallel damper silencer housing (6), wherein between the slotted silencer housings (6) air gaps (10) are arranged, through which the medium can flow

characterized,

in that a sound absorber, in particular a microperforated absorber (7), is placed on the end faces of the slotted silencer housings (6) facing the sound source (11) or a microperforated absorber (7.6) is inserted between adjacent silencer housing parts (5.1, 5.2) in the direction of flow.

2. Silencer arrangement according to claim 1,

characterized,

in that the microperforation and the width and the depth of the absorber (7) are chosen such that absorption takes place in a desired frequency spectrum.

3. Silencer arrangement according to one of claims 1 or 2,

characterized,

the absorber (7, 7.1) has a microperforated wall (9, 9.1) which is oriented towards the sound source (1 1).

4. Silencer arrangement according to one of the preceding claims, characterized

the absorber (7.2) has a microperfoned wall (9.2) which is oriented in the direction of the air gaps (10).

5. Silencer arrangement according to one of the preceding claims,

characterized,

that the absorber (7.3, 7.4) has two or more microperfonated walls (9.2, 9.3, 9.4) oriented in two or more directions.

6. Silencer arrangement according to one of the preceding claims,

characterized,

that the absorber (7.5) has a curved microperfonated wall (9.5), which is oriented to the sound source (1 1).

7. Silencer arrangement according to one of the preceding claims,

characterized,

the absorber (7) is subdivided into partial volumes in the direction of its largest dimension by a separating element (12) or a plurality of separating elements.

8. Silencer arrangement according to one of the preceding claims,

characterized,

the absorber (7) has an additional rear wall (8).

9. Silencer arrangement according to one of the preceding claims,

characterized,

the absorber (7.6) inserted between adjacent slotted silencer housing parts (5.1, 5.2) has one or two microperforated walls (9.2, 9.3) oriented in the direction of the air gap (s) (10).

10. Slotted silencer for Schalldämpfanordnungen according to any one of claims 1 -9,

characterized in that

on the upstream side of the slotted silencer (6) a hollow body with micro perforations can be placed or placed.