INTERFERENCE NOISE-CONTROL UNIT

Abstract

The present inventive concept relates to an interference noise-control unit, for installation on a sound arresting wall for reducing noise from trains or cars. The interference noise-control unit comprises: a housing to be secured on a sound arresting wall. The housing comprises a hollow compartment comprising at least one first channel and at least one second channel, wherein the first channel has a first channel height A and a first channel length B, and wherein the second channel has a second channel height A′ and a second channel length B′, and wherein the first channel height A is different from the second channel height A′.

Claims

1. An interference noise-control unit, for installation on a sound arresting wall for reducing noise from trains, comprising: a housing to be secured on a sound arresting wall, wherein the housing comprises a hollow compartment comprising at least one first channel and at least one second channel, wherein said first channel has a first channel height A and a first channel length B, and wherein said second channel has a second channel height A′ and a second channel length B′, and wherein said first channel height A is different from said second channel height A′.

2. An interference noise-control unit according to claim 1, wherein said first channel height A is larger than said second channel height A′ and wherein said first channel length B is larger than said second channel length B′.

3. An interference noise-control unit according to claim 1, further comprising a third channel having a third channel height A″ which is equal to or smaller than said second channel height A′ and a third channel length B″ which is equal to or smaller than said second channel length B′.

4. An interference noise-control unit according to claim 3, wherein said first channel height A is between 80-100 mm, said second channel height A′ is between 50-70 mm, and said third channel height A″ is between 30-50 mm.

5. An interference noise-control unit according to claim 1, wherein said first channel length B is between 0.08-1.1 m and wherein said second channel length B′ is between 0.05-0.8 m.

6. An interference noise-control unit according to claim 1, wherein the inlet height of said interference noise-control unit is between 100-300 mm.

7. An interference noise-control unit according to claim 1, wherein the total number of channels are 3-4.

8. An interference noise-control unit according to claim 1, wherein said second channel is located on top of said first channel.

9. An interference noise-control unit according to claim 3, wherein the relationship between said first channel height A and said second channel height A′ is in the interval of 1.1-3.0.

10. An interference noise-control unit according to claim 1, wherein said channels are bent and having one essentially vertical length portion with an opening facing the noise source and one essentially horizontal length portion.

11. An interference noise-control unit according to claim 1, wherein said channels are essentially straight and vertically directed.

12. An interference noise-control unit according to claim 1, wherein said housing comprises a case and an insert, said insert comprising a plurality of baffles forming said channels.

13. A process for making an interference noise-control unit, comprising the steps of: extruding a case, injection moulding an insert, mounting said case on a sound arresting wall, and mounting said insert to said case.

14. An interference noise-control unit according to claim 9, wherein the relationship between said second channel height A′ to said third channel height A″, is in the interval of 1.1-3.0.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The present inventive concept will now be described in more detail, with reference to the appended drawings showing example embodiments, wherein:

[0058] FIG. 1a illustrates, in a perspective view, the interior of an interference noise-control unit according to at least one example embodiment of the inventive concept;

[0059] FIG. 1b illustrates, in a cross-sectional view, the interference noise-control unit shown in FIG. 1a; FIG. 1b may also illustrate a cross section of the embodiment of FIG. 2c.

[0060] FIG. 1c illustrates, in a perspective view, the interference noise-control unit shown in FIGS. 1a and 1b;

[0061] FIGS. 2a and 2b illustrate, in a perspective view, an assembly of a plurality of parallel interference noise-control units shown in FIG. 1a-1c, when installed on a sound arresting wall.

[0062] FIG. 2c illustrates, in a perspective view, an interference noise-control unit according to at least one example embodiment of the inventive concept.

[0063] FIG. 3 illustrates, in a cross-sectional view, an interference noise-control unit according to at least one example embodiment of the inventive concept.

DETAILED DESCRIPTION OF THE DRAWINGS

[0064] In the following description, the present inventive concept is described with reference to an interference noise-control unit, for installation on a sound arresting wall for reducing noise from trains or cars.

[0065] FIGS. 1a, 1b and 1c illustrate an interference noise-control unit 1 to be installed on a sound arresting wall. The interference noise-control unit 1 comprises a first channel 10 having a first channel height A and a first channel length B, a second channel 20 having a second channel height A′ and a second channel length B′, a third channel 30 having a third channel height A″ and a third channel length B″, and a fourth channel 40 having a fourth channel height A′″ and a fourth channel length B′″. I.e. each one of the channels illustrated in FIGS. 1a, 1b, and 1c has a distinct channel height and a distinct channel length. Furthermore, the channels 10, 20, 30, 40, shown in FIGS. 1a, 1b, and 1c, are positioned such that the first channel 10, having the largest channel height and longest channel length, is below the others. The channels on top of the first channel 10 are arranged with decreasing channel height and channel length the further up they are positioned.

[0066] The channels 10, 20, 30, 40 are separated from each other by a plurality of angled baffles 15. In FIGS. 1a, 1b, and 1c, five baffles 15 of unequal lengths are positioned with different interspaces in between. The interspace between two adjacent baffles 15 defines the channel height of the respective channel. As shown in the FIGS. 1a, 1b and 1c, each channel height is constant throughout the whole channel.

[0067] When noise reaches the interference noise-control unit 1 sound waves enter the channels 10, 20, 30, 40. In the channels, the sound waves are shifted in phase such that the frequencies of the emerging sound waves are shifted in phase compared to the frequencies of the sound waves having not passed the interference noise-control unit 1. When the emerging sound waves then meet the sound which has not passed the interference noise-control unit 1 interference appears and a sound volume reducing zone is provided.

[0068] Since each one of the channels 10, 20, 30, 40, shown in FIGS. 1a, 1b and 1c, has a distinct channel length the interval of the interference spectrum is enlarged.

[0069] FIGS. 2a and 2b illustrate an assembly 100 of a plurality of parallel interference noise-control units 1 installed on a sound arresting wall 50. The interference noise-control units 1 are installed with the inlet 5 of the interference noise-control unit facing the noise source (not shown in the figures). The inlet 5 of the interference noise-control unit 1, also shown in FIG. 1c, is positioned on top of the sound arresting wall 50. Channels 10, 20, 30, 40, encompassed within a housing 70, extend to the back of the sound arresting wall 50. I.e. the inlet 5 of the interference noise-control unit 1 rests on the sound arresting wall 50 while the housing 70 is positioned behind the sound arresting wall 50. Alternatively, the interference noise-control unit may be positioned on the side of the sound arresting wall, preferably on the side facing the noise source. Hereby, both the inlet and the housing is positioned in front of the sound arresting wall, seen from the position of the noise source. This position is advantageous in that the interference noise-control unit is less visible from the outside of the sound arresting wall. For clarity is a side wall 7 of the housing 70 removed in FIGS. 2a and 2b. The upper portion of the interference noise-control unit 1 is open such that the incoming sound waves are allowed to exit on top of the interference noise-control unit 1. Hence, the out coming waves meet the noise on top of the interference noise-control unit 1 and the sound volume reducing zone is provided around the interference noise-control unit 1 and the sound arresting wall 50.

[0070] FIGS. 2a and 2b are shown in a perspective view to envisage that the interference noise-control unit 1 may be installed on an existing sound arresting wall 50 and that the existing sound arresting wall 50 may be shaped in different heights or lengths.

[0071] FIG. 2c illustrates an interference noise-control unit 1′ made up of a shell or case 80 and a plurality of inserts 90. The case 80 and the inserts 90 together form a housing 70 which is mounted on a sound arresting wall 50. The case 80 is manufactured in one piece and the insert 90 is manufactured in a second piece which is mounted on the case 80. Hereby, the insert 90 may be exchanged while the case 80 is still mounted on the sound arresting wall 50.

[0072] FIG. 3 illustrates an interference noise-control unit 1″ which has an inlet without any channels. The channels 10, 20, 30, 40 are connected to the outlet 6 of the interference noise-control unit 1″, i.e. the baffles 15 are located vertically and essentially straight. Since there is no horizontal path of the channels 10, 20, 30, 40, in FIG. 3, the channel width is thus understood to be interpret as the channel height. Each one of the channels 10, 20, 30, 40 has a distinct channel width/height A, A′, A″, A′″ and a distinct channel length B, B′, B″ B′″.