CN105195273A - Preparation method of damping combined type acoustic shield - Google Patents
Preparation method of damping combined type acoustic shield Download PDFInfo
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- CN105195273A CN105195273A CN201510609993.7A CN201510609993A CN105195273A CN 105195273 A CN105195273 A CN 105195273A CN 201510609993 A CN201510609993 A CN 201510609993A CN 105195273 A CN105195273 A CN 105195273A
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Abstract
The invention provides a preparation method of a damping combined type acoustic shield, and relates to a preparation method of a mechanical acoustic shield. The method comprises the design of three aspects including the acoustic design, the appearance design and the structural design, of the acoustic shield. The acoustic design comprises the steps of noise signal measurement, noise frequency band component analysis, noise source analysis, noise field simulation and sound absorption and insulation structure determination, characteristic signals of noise are extracted by applying wavelets, and then the noise source characteristics of different component parts of equipment are analyzed by applying the blind source separation technology; multiple modes can be adopted to combine sound absorption materials and perforated plates. According to the preparation method of the damping combined type acoustic shield, analysis is conducted on the noise of a ball mill, a frequency spectrum of the ball mill is analyzed according to measured noise signals, and the main frequency for producing the noise is judged. Meanwhile, detection analysis is conducted on on-site noise sources and propagation paths, and a noise control scheme which can interdict sound propagation from the two aspects of sound absorption and insulation is made, so that an ideal effect on noise reduction is achieved.
Description
Technical field
The present invention relates to a kind of preparation method of mechanical acoustic hood, particularly relate to a kind of preparation method of damping combined type acoustic hood.
Background technology
Ball mill is widely used Super-fine grinder plant equipment in domestic and international industrial production, ball mill is of wide application, and is widely used in ore dressing, the industry such as cement building material and chemical industry, but ball mill can produce great noise in the course of the work, very harmful to the personnel near it; When ball mill barrel is exposed, noise figure can up to more than 110dB (A), be in each industrial production of the world today plant equipment produce produce one of the most serious noise source of noise pollution.Therefore, the noise abatement of ball mill becomes one of problem of Chinese scholars extensive concern, has obtained certain effect in noise abatement simultaneously.But the material of application ball coal pulverizer acoustic hood is more single at present, structure is also fairly simple, normally using the material such as asphaltic base and rubber as damping vibration attenuation material, using the porous sound-absorbing material such as asbestos wool and mineral wool as main body sound-absorbing material, therefore, the noise abatement effect of ball mill has breakthrough more difficult.
Summary of the invention
The object of the present invention is to provide a kind of preparation method of damping combined type acoustic hood, the method is analyzed ball mill noise, according to surveyed noise signal, analyzes its frequency spectrum, judges the main frequency producing noise.Carry out detection to the noise source at scene and propagation path to analyze simultaneously, and block the noise abatement scheme of sound transmissions from sound absorption and sound insulation two aspects, make noise reduction reach ideal effect.
The object of the invention is to be achieved through the following technical solutions:
A kind of preparation method of damping combined type acoustic hood, described method comprises acoustic hood three aspect designs, for acoustics design, appearance design, structural design, acoustics design comprises the measurement of noise signal, noise band constituent analysis, noise-source analysis, the simulation of noise sound field and the determination of sound absorption and insulation structure, application small echo extracts the characteristic signal of noise, then applies the noise source feature that blind separation technology carrys out the different part of analytical equipment; Sound-absorbing material and perforated plate be compounded with various ways, for the consideration increasing acoustic resistance in perforated plate cavity, sound-absorbing material is close to perforated plate and places; After ball mill noise is analyzed, according to surveyed noise signal, its frequency spectrum is analyzed, judge the main frequency producing noise; Carry out detection to the noise source at scene and propagation path to analyze simultaneously, and block the noise abatement scheme of sound transmissions from sound absorption and sound insulation two aspects; Acoustic hood shell is made up of the air-locked metal material with constant weight and rigidity of one deck, with the steel plate of two millimeters thick, and layer overlay damping layer; The fabric that damping layer pitch damping glue is soaked into or fibrous material, soak sackcloth, glass cloth, felt class or asbestos wool with pitch, what have uses damping slurry.
Advantage of the present invention and effect are:
1. the present invention makes noise reduction reach ideal effect, can meet the requirement of national technical standard completely, for the noise processed of other ball mill provides reference.
2. the present invention carries out detection analysis to the ball mill noise sound source at scene and propagation path, and has set forth from sound absorption and sound insulation two aspects the noise abatement scheme blocking sound transmission, makes noise reduction reach ideal effect.Be particularly suitable for the improvement of the main equipment noises such as steam turbine, wind energy conversion system, air blast, greatly can reduce the noise of equipment, economic benefit is obvious.
3. the present invention is applied in certain enterprise's ball mill machine room, and engineering practice shows, this acoustic hood noise reduction is good, various types of ball mill noise can be controlled within state specified standards scope completely.
4. the present invention analyzes ball mill noise, according to surveyed noise signal, analyzes its frequency spectrum, judges the main frequency producing noise.Carry out detection to the noise source at scene and propagation path to analyze simultaneously, and block the noise abatement scheme of sound transmissions from sound absorption and sound insulation two aspects, make noise reduction reach ideal effect.
Accompanying drawing explanation
Fig. 1 is acoustic hood design sketch.
Detailed description of the invention
The design process of acoustic hood, according to the difference of noise abatement field condition, is divided into acoustics design, appearance design, structural design three aspects by the present invention:
Acoustics design mainly comprises the measurement of noise signal, noise band constituent analysis, noise-source analysis, the simulation of noise sound field and the determination of sound absorption and insulation structure.The structure of general large-sized power plant and residing environment all more complicated, produce noise sound field by a sound source and sound source through factors such as reflections very complicated.In order to analyze the noise contribution of large-sized power plant accurately, we apply the characteristic signal that small echo extracts noise, then apply the noise source feature that blind separation technology carrys out the different part of analytical equipment.
Because the noise signal signal to noise ratio collected is low, ambient noise is large and mostly signal is that unit mixed noise is difficult to differentiate real sources, conceals a large amount of false useless our judgement of effect of signals in therefore gathered acoustic signal.Wavelet analysis is due to the automatic telescopic of its basic function and translation feature, become now the important tool of signal analysis, we are based on Wavelet Analysis Theory, feature extraction is carried out to the noise signal gathered, filter that to account for gross energy ratio very little and affect little interfering signal to noise reduction, the characteristic signal extracted, as the output signal of blind source separating, analyzes the noise source characteristic of unit different parts.
The noise that large-sized power plant produces has bandwidth usually, the feature that amplitude is high, and common sound-absorbing material, as mineral wool, the sound-absorbing materials such as rock wool are all have higher acoustic absorptivity to high-frequency noise, and it is unsatisfactory to the acoustically effective of low frequency, for the feature of the noise that large-sized power plant produces, we with the mineral wool board of high-quality for base material, based on the Micro_perforated resonance theory of China famous acoustics expert Ma Dayou academician, invent, to low frequency, there is " Assembled plate for absorbing acoustic energy " compared with high acoustic absorption performance, and obtained accepting of Patent Office of State Intellectual Property Office.
Assembled plate for absorbing acoustic energy is theoretical according to helmholtz resonance, certain thickness sheet material bores a hole and can improve the noise reduction capability of structure to low-frequency noise in conjunction with certain thickness air layer having.Perforated plate can regard the parallel connection of a large amount of short tube as.
Helmholtz resonator is an airtight inside is the container of crust, the structure be associated with outside atmosphere by a little opening.The acoustic element that single resonator can be regarded as by several acoustics effect is different formed, and air vibrates with sound wave in open tube and near the mouth of pipe, is an acoustic mass element.Pressure in cavity changes with the breathing of air, is an acoustic compliance element.And the air in cavity vibrates with sound wave in a certain degree, also there is certain acoustic mass.Air is in the vibration friction of opening wall, and due to the effect of viscous damping and heat conduction, can make sound energy loss, its acoustics effect is an acoustic resistance.When the intrinsic frequency of incident sound wave frequency close to resonator, the air column of pore-throat produces judder, in vibration processes, owing to overcoming frictional resistance and sound energy consumption.Otherwise when incident acoustic wave frequency is away from resonator intrinsic frequency, resonator vibration is very weak, and therefore sound absorption effect is very little, and visible resonator acoustic absorptivity changes with frequency, and most high acoustic absorption coefficient appears at resonant frequency place.
When sound wave incident is to the entrance of Helmholz resonance sound absorber, the air of container internal orifice is encouraged, and generation is vibrated, and the medium in container is by generation compression or dilatancy, according to substitutional connection map analysis, the equivalent acoustic impedance that can obtain single Helmholz resonance sound absorber is:
（1）
In formula,
for acoustic impedance;
for the acoustic mass of Helmholz resonance sound absorber.Wherein
for atmospheric density,
for inlet length, S inlet tube area;
for the acoustic compliance of Helmholz resonance sound absorber, wherein
for container volume.
The resonant frequency of single Helmholz resonance sound absorber can be obtained by above formula
can be tried to achieve by following formula:
（2）
The sound absorbing mechanism of perforated plate comes from this just, and the hole on perforated plate and air layer below just in time form helmholtz resonance body, when the noise frequency of incidence and the resonant frequency of perforation board resonance sound absorption structure consistent time, the acoustic energy of consumption is maximum.Consider that perforated plate is that multiple Helmholtz resonator is formed in parallel, when sound wave vertical incidence, its resonance sound-absorbing frequency and the following formulae discovery of acoustic absorptivity:
（3）
（4）
（5）
As shown from the above formula, the resonant frequency of perforated plate and acoustic absorptivity and punching rate p, aperture d, perforated plate thickness h is relevant with air layer thickness D.Because the volume of large-sized power plant itself is very huge, if air layer thickness is excessive, then take up room excessive, this is disadvantageous for structural design, in Practical Project, thus all will reduce the thickness of air layer as far as possible.
Sound-absorbing material and perforated plate be compounded with various ways, for the consideration increasing acoustic resistance in perforated plate cavity, sound-absorbing material is close to perforated plate and places, as shown in Figure 1.
Be applied in the noise abatement engineering of the pharmacy head factory northeastward of this compound sound-absorption structural above, effect is fairly obvious, average noise reduction is more than very shellfish, and for having the higher situation of multiple low-frequency noise amplitude, we take the perforation board resonance sound absorption structure with different pore size, this structure is also applied in practice, and effect is better.
What the partiting sound member in noise reduction engineering adopted usually is the combination that damping paint adds steel plate, oise insulation factor depends primarily on the surface density of material, steel plate is thicker, oise insulation factor is larger, but also create a lot of problem, as steel plate is thicker, cost is higher thereupon, site operation is more difficult, and damping lacquer coat is thicker.Take into account the factors such as noise reduction, construction costs and construction, under identical oise insulation factor, the weight of this damping sound-insulation board will add the structure of steel plate far below damping paint, and owing to decreasing the thickness of plate, greatly reduces difficulty and the construction costs of construction.
Take to administer rear sound deadening capacity and reach 30.0dB (A).After installing acoustic hood, the noise of whole compressor obviously reduces, and meanwhile, in improvement, take into account the environmental requirements such as waterproof fireproofing, and cooling tower service behaviour is normal.Through the field monitoring of environmental administration, apart from office building 1 meter of, the noise on daytime is down to 48.5dB (A), and the noise at night is down to 44.5dB (A), reaches I class standard in " standard of environmental noise of urban area ".Facts have proved, the applicability of this cover Noise control program is very wide, successful.
Claims (1)
1. the preparation method of a damping combined type acoustic hood, it is characterized in that, described method comprises acoustic hood three aspect designs, for acoustics design, appearance design, structural design, acoustics design comprises the measurement of noise signal, noise band constituent analysis, noise-source analysis, the simulation of noise sound field and the determination of sound absorption and insulation structure, application small echo extracts the characteristic signal of noise, then applies the noise source feature that blind separation technology carrys out the different part of analytical equipment; Sound-absorbing material and perforated plate be compounded with various ways, for the consideration increasing acoustic resistance in perforated plate cavity, sound-absorbing material is close to perforated plate and places; After ball mill noise is analyzed, according to surveyed noise signal, its frequency spectrum is analyzed, judge the main frequency producing noise; Carry out detection to the noise source at scene and propagation path to analyze simultaneously, and block the noise abatement scheme of sound transmissions from sound absorption and sound insulation two aspects; Acoustic hood shell is made up of the air-locked metal material with constant weight and rigidity of one deck, with the steel plate of two millimeters thick, and layer overlay damping layer; The fabric that damping layer pitch damping glue is soaked into or fibrous material, soak sackcloth, glass cloth, felt class or asbestos wool with pitch, what have uses damping slurry.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2845090Y (en) * | 2005-09-19 | 2006-12-06 | 沈阳工业大学 | Assembled plate for absorbing acoustic energy |
| WO2013072629A1 (en) * | 2011-11-14 | 2013-05-23 | Centre D'etude Et De Recherche Pour L'automobile (Cera) | Thin acoustic protection device intended to be installed against a wall of an electric motor casing for a motor vehicle |
| CN104131626A (en) * | 2014-07-16 | 2014-11-05 | 沈阳化工大学 | Turboset noise control method |
| CN104484504A (en) * | 2014-11-25 | 2015-04-01 | 沈阳化工大学 | Ball mill machine room noise control method |
-
2015
- 2015-09-23 CN CN201510609993.7A patent/CN105195273A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2845090Y (en) * | 2005-09-19 | 2006-12-06 | 沈阳工业大学 | Assembled plate for absorbing acoustic energy |
| WO2013072629A1 (en) * | 2011-11-14 | 2013-05-23 | Centre D'etude Et De Recherche Pour L'automobile (Cera) | Thin acoustic protection device intended to be installed against a wall of an electric motor casing for a motor vehicle |
| CN104131626A (en) * | 2014-07-16 | 2014-11-05 | 沈阳化工大学 | Turboset noise control method |
| CN104484504A (en) * | 2014-11-25 | 2015-04-01 | 沈阳化工大学 | Ball mill machine room noise control method |
Non-Patent Citations (3)
| Title |
|---|
| 刘欢等: "煤矿企业球磨机机房噪声分析与治理", 《工业安全与环保》 * |
| 刘欢等: "阻尼复合式隔声罩设计与应用", 《第十二届沈阳科学学术年会论文集（理工农医）》 * |
| 赵召等: "复合式降噪板在球磨机机房噪声治理中的应用", 《中国资源综合利用》 * |
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