Two-stage expansion noise elimination structure

Abstract

The invention discloses a two-step expansion noise elimination structure arranged outside a fixed opening of noise equipment. The two-step expansion noise elimination structure comprises three sound insulation and absorption components parallel to the vertical face of the fixed opening of the equipment, and sound insulation and absorption components arranged on the periphery of the sound insulation and absorption components on the vertical face. A hole is formed in the middle of the vertical face sound insulation and absorption component, and the hole position is consistent with the equipment fixing opening direction; the first vertical face sound insulation and absorption component, the second vertical face sound insulation and absorption component and a cavity between the first vertical face sound insulation and absorption component and the second vertical face sound insulation and absorption component form a first-stage expansion noise elimination structure, and the second vertical face sound insulation and absorption component, the third vertical face sound insulation and absorption component and a cavity between the second vertical face sound insulation and absorption component and the third vertical face sound insulation and absorption component form a second-stage expansion noise elimination structure. And the cavity width of the first-stage expansion silencing structure is greater than that of the second-stage expansion silencing structure.

Description

Technical Field

[0001] The present invention relates to the technical field of ventilation noise reduction, and particularly to a two-stage expansion silencing structure with a fixed outlet. Background Art

[0002] Currently, noise has become a major environmental pollution. In particular, the noise of production equipment in industrial enterprises has a great impact on the health of production personnel, and noise is a major occupational disease. At present, high-noise equipment mainly adopts the method of equipment sound insulation enclosures. However, due to the technological requirements of some equipment, certain unobstructed fixed openings need to be reserved, which thus forms the main propagation path of equipment noise. As a result, it is difficult to eliminate the impact of equipment noise, and the workshop environmental noise of many industrial enterprises often fails to meet the requirements of the "Industrial Enterprise Noise Hygiene Standard".

[0003] The noise reduction of high-noise equipment with fixed openings is a difficult point in the noise reduction project, which will greatly reduce the insertion loss dB(A) of the sound insulation enclosure of high-noise equipment. According to the Industrial Enterprise Noise Control Design Specification GB / T 50087-2013, Table 5.1.3 Insertion Loss of Sound Insulation Enclosure: When the structure type of the sound insulation enclosure is a partially open type, its insertion loss is only 10 dB(A) - 20 dB(A). Summary of the Invention

[0004] In order to solve the impact of high-noise equipment with fixed openings on the acoustic environment, the present invention provides a two-stage expansion silencing structure, which can absorb the equipment noise transmitted through the fixed opening while keeping the fixed opening of the equipment unobstructed, and is convenient to use and simple to maintain.

[0005] The technical solution adopted by the present invention to solve its technical problems is: A two-stage expansion silencing structure arranged outside the fixed opening of a noise equipment, comprising three sound insulation and absorption components parallel to the vertical surface of the equipment fixed opening, and sound insulation and absorption components arranged around the outside of the vertical surface sound insulation and absorption components. An opening is provided in the middle of the vertical surface sound insulation and absorption component, and the opening position is consistent with the direction of the equipment fixed opening; the first vertical surface sound insulation and absorption component, the second vertical surface sound insulation and absorption component of the equipment fixed opening and the cavity therebetween form a first-stage expansion silencing structure, the second vertical surface sound insulation and absorption component, the third vertical surface sound insulation and absorption component and the cavity therebetween form a second-stage expansion silencing structure, and the cavity width of the first-stage expansion silencing structure is greater than the cavity width of the second-stage expansion silencing structure.

[0006] The flow direction of the gas is from high pressure to low pressure. Because as long as there is a pressure difference in the horizontal direction, a force will be generated that flows from the high-pressure area to the low-pressure area. This force is called the horizontal pressure gradient force. Under the action of the horizontal pressure gradient force, air flows from the high-pressure area to the low-pressure area. The characteristic of the horizontal pressure gradient force is that it is perpendicular to the isobar, and its direction is from high pressure to low pressure. The pressure gradient is the pressure difference per unit distance. Once there is a difference in high and low pressure, there will be a force that causes the air in the high-pressure area to flow towards the low-pressure direction. Just like water flowing from a high place to a low place, the action of this force forms wind, and the magnitude of the wind speed depends on the magnitude of the horizontal pressure gradient force. The propagation of air noise is a divergent spherical propagation from the sound source to the surroundings, and geometric divergence attenuation occurs during the propagation process due to the increase in distance.

[0007] The fixed openings of the noise equipment mentioned above include the conveyor belt opening, the inlet and outlet openings, etc. The area of the sound insulation and absorption component is more than 10 times the area of the opening. When the noise during the operation of the noise source equipment propagates outward through the fixed opening, the fixed opening forms a hemispherical propagation with the noise source diverging to the surroundings. At the opening of the sound insulation and absorption component of the first-stage expansion muffling structure, a cross-section sudden expansion occurs, and the sound energy of the noise diffuses. Most of the sound waves diffuse towards the sound insulation and absorption component and are absorbed. The sound pressure per unit area in the expansion area is one over the multiple of the expansion ratio, so as to fully expand, reduce pressure, and decelerate. The weakened noise passes through the second-stage expansion muffling structure for cross-section sudden expansion again, and the sound energy of the noise diffuses. The muffling effect of the muffling expansion area is related to several times the cross-section expansion ratio of the air outlet, and it has an effective muffling effect on low-frequency and some medium-frequency sounds, and has a good muffling effect on medium-high frequency sounds. It is a wide-spectrum muffling structure. The larger the multiple of the cross-section sudden expansion ratio, the better the muffling effect.

[0008] The cavity of the first-stage expansion muffling structure mentioned above is larger than one-quarter of the wavelength of the lowest-frequency peak of the frequency band to be muffled; the cavity of the second-stage expansion muffling structure is larger than one-quarter of the wavelength of the second-lowest-frequency peak of the frequency band to be muffled. When the internal spacing of the expansion muffling structure is greater than or equal to 1 / 4 wavelength, the maximum blocking effect can be obtained. Since the frequency band to be muffled has a certain bandwidth, when the muffling frequency band is set at the lowest-frequency peak and the main frequency band peak, the best muffling effect can be obtained.

[0009] The vertical sound insulation and absorption components and the surrounding sound insulation and absorption components mentioned above include an absorption structure and a sound insulation structure. The absorption frequency band of the absorption structure on the inner side of the cavity should meet the design requirements of the muffling frequency band. It can absorb the sound waves diffusing towards the sound insulation and absorption components to the greatest extent, reduce reflection, and improve the muffling efficiency. A thin film with a corresponding thickness is lined outside the absorption structure of the first-stage expansion muffling structure to meet the absorption of the low-frequency muffling frequency band. The thin film layer forms a resonance absorption structure, forming a composite absorption structure. Increasing the thickness of the thin film can shift the absorption peak of the resonance absorption structure towards the low-frequency direction, and can further improve the absorption of low-frequency sound waves.

[0010] The beneficial effects of the present invention are that it can satisfy the transmission of equipment noise through fixed openings, improve the sound insulation efficiency of the equipment sound insulation cover, and reduce the impact on the workshop sound environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described below in conjunction with the drawings and embodiments.

[0012] Figure 1 It is a side view of an embodiment of the present invention.

[0013] Figure 2 It is a front view of an embodiment of the present invention.

[0014] In the figure, 1. Equipment, 11. Opening, 2. Expansion muffler structure, 21. Vertical sound insulation and absorption member, 211. Opening, 22. Peripheral sound insulation and absorption member, 23. Cavity, 24. Absorption structure, 241. Film, 25. Sound insulation structure. EMBODIMENTS

[0015] In Figure 1 、 2 In the shown embodiment, an expansion muffler structure (2) provided outside the fixed opening (11) of a noise equipment (1) includes three sound insulation and absorption members (21) parallel to the vertical surface of the fixed opening (11) of the equipment (1), and a peripheral sound insulation and absorption member (22) arranged outside the vertical sound insulation and absorption member (21). An opening (211) is provided in the middle of the vertical sound insulation and absorption member (21), and the position of the opening (211) is consistent with the direction of the fixed opening (11) of the equipment (1); the first vertical sound insulation and absorption member (21), the second vertical sound insulation and absorption member (21) of the fixed opening (11) of the equipment (1), and the cavity (23) therebetween form a first-stage expansion muffler structure (2), and the second vertical sound insulation and absorption member (21), the third vertical sound insulation and absorption member (21) of the fixed opening (11) of the equipment (1), and the cavity (23) therebetween form a second-stage expansion muffler structure (2). The width of the cavity (23) of the first-stage expansion muffler structure (2) is greater than the width of the cavity (23) of the second-stage expansion muffler structure (2).

[0016] The area of the vertical sound insulation and absorption member (21) is more than 10 times the area of the opening (211). The cavity (23) of the first-stage expansion muffler structure (2) is greater than one-quarter of the wavelength of the lowest frequency peak of the frequency band to be muffled; the cavity (23) of the second-stage expansion muffler structure (2) is greater than one-quarter of the wavelength of the sub-lowest frequency peak of the frequency band to be muffled.

[0017] The described facade sound insulation and absorption component (21) and the surrounding sound insulation and absorption component (22) include an absorption structure (24) and a sound insulation structure (25). The absorption frequency band of the absorption structure on the inner side of the cavity should meet the design requirements of the anechoic frequency band. A thin film (241) is lined outside the absorption structure (24) of the first-order expansion anechoic structure (2) to improve the absorption of the low-frequency anechoic frequency band.

[0018] The above embodiments are only used to further illustrate a two-order expansion anechoic structure of the present invention. However, the present invention is not limited to the embodiments. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the technical solution of the present invention.

Claims

1. A two - stage expansion muffler structure arranged outside the fixed opening of a noise device, comprising three vertical sound insulation and absorption components parallel to the vertical surface of the device's fixed opening, and sound insulation and absorption components arranged around the outside of the vertical sound insulation and absorption components. Its characteristics are: An opening is arranged in the middle of the vertical sound insulation and absorption component, and the position of the opening is consistent with the direction of the device's fixed opening; the first vertical sound insulation and absorption component, the second vertical sound insulation and absorption component of the device's fixed opening, and the cavity between them form a first - stage expansion muffler structure, and the second vertical sound insulation and absorption component, the third vertical sound insulation and absorption component, and the cavity between them form a second - stage expansion muffler structure. The cavity width of the first - stage expansion muffler structure is greater than the cavity width of the second - stage expansion muffler structure.

2. The two - stage expansion muffler structure according to claim 1: Its characteristics are, The area of the vertical sound insulation and absorption component is more than 10 times the area of the opening.

3. The two - stage expansion muffler structure according to claim 1: Its characteristics are, The cavity of the first - stage expansion muffler structure is greater than one - quarter of the wavelength of the lowest - frequency peak value in the frequency band to be muffled, and the cavity of the second - stage expansion muffler structure is greater than one - quarter of the wavelength of the sub - lowest - frequency peak value in the frequency band to be muffled.

4. The two - stage expansion muffler structure according to claim 1: Its characteristics are, The vertical sound insulation and absorption components and the surrounding sound insulation and absorption components include an absorption structure and a sound insulation structure, and the absorption frequency band of the absorption structure on the inner side of the cavity should meet the design requirements of the muffling frequency band.

5. The two - stage expansion muffler structure according to claim 1: Its characteristics are, A thin film is lined outside the absorption structure of the first - stage expansion muffler structure to improve the absorption of the low - frequency muffling frequency band.

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