CN113628605B - Noise reduction device for on-site maintenance of gas turbine - Google Patents
Noise reduction device for on-site maintenance of gas turbine Download PDFInfo
- Publication number
- CN113628605B CN113628605B CN202110882578.4A CN202110882578A CN113628605B CN 113628605 B CN113628605 B CN 113628605B CN 202110882578 A CN202110882578 A CN 202110882578A CN 113628605 B CN113628605 B CN 113628605B
- Authority
- CN
- China
- Prior art keywords
- layer
- noise reduction
- noise
- gas turbine
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000012423 maintenance Methods 0.000 title claims abstract description 28
- 238000013016 damping Methods 0.000 claims abstract description 39
- 239000007788 liquid Substances 0.000 claims abstract description 33
- 238000010521 absorption reaction Methods 0.000 claims abstract description 20
- 238000007789 sealing Methods 0.000 claims description 3
- 239000010410 layer Substances 0.000 description 84
- 230000000694 effects Effects 0.000 description 12
- 230000005540 biological transmission Effects 0.000 description 8
- 230000002238 attenuated effect Effects 0.000 description 5
- 230000006378 damage Effects 0.000 description 4
- 239000002356 single layer Substances 0.000 description 4
- 206010011878 Deafness Diseases 0.000 description 2
- 208000028571 Occupational disease Diseases 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
- 208000016354 hearing loss disease Diseases 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 230000001360 synchronised effect Effects 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 231100000895 deafness Toxicity 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 210000003027 ear inner Anatomy 0.000 description 1
- 231100000888 hearing loss Toxicity 0.000 description 1
- 230000010370 hearing loss Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 210000005036 nerve Anatomy 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
- G10K11/168—Plural layers of different materials, e.g. sandwiches
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
The invention relates to a noise reduction device for on-site maintenance of a gas turbine, which comprises a noise reduction blanket, wherein the noise reduction blanket is arranged on the outer surface of a noise source, the noise reduction blanket at least comprises a gas-liquid mixing layer, a honeycomb layer, a vibration absorption column, a flexible layer and a damping layer, the flexible layer is a contact surface between the noise reduction blanket and the outer surface of the noise source, the flexible layer, the damping layer, the honeycomb layer and the gas-liquid mixing layer are sequentially arranged adjacently, the vibration absorption column is arranged in the damping layer, and the vibration absorption column is cylindrical or conical or strip-shaped.
Description
Technical Field
The invention relates to the technical field of noise reduction devices for on-site maintenance of gas turbines, in particular to a noise reduction device for on-site maintenance of gas turbines.
Background
At present, a traditional gas turbine power station matched noise reduction system is fixed, and power generation work is carried out in a certain planning area; the workshop site of the gas turbine has very loud noise, the most direct damage of the noise to the human body is the damage of the hearing system, and the damage of the permanent nerve hearing system of the inner ear is mainly caused by high-intensity noise; the noise hearing loss is an important cause of disability, and is identified as the second most occupational disease and industrial injury, and the noise deafness is listed as legal occupational disease in China; the 25000KW gas turbine gives out about 140dB (A) of noise when working, influences the normal work and life of the periphery, so that the office setting on site is far away, moreover, the influence on the personnel on site and maintenance and inspection personnel which need to enter the site cannot be avoided is very large, the maintenance time sometimes reaches 3-5 working days, more than 40 working hours are required, the noise cannot be overcome by adopting simple protection for operators, the site space is large, the walking of the maintenance personnel and the like have small influence on noise reduction, meanwhile, long-time operation is difficult to realize by using sound insulation earplugs and the like, and the problem that the human body is damaged due to variable noise overrun caused by the walking of the personnel cannot be satisfied.
Disclosure of Invention
The invention aims to provide a noise reduction device for on-site maintenance of a gas turbine, which has the characteristics of simple structure, low cost, convenient implementation, dynamic noise reduction and active and passive noise reduction.
In order to solve the problems, the invention provides a noise reduction device for on-site maintenance of a gas turbine, which comprises a noise reduction blanket, wherein the noise reduction blanket is arranged on the outer surface of a noise source, the noise reduction blanket at least comprises a gas-liquid mixing layer, a honeycomb layer, a vibration absorption column, a flexible layer and a damping layer, the flexible layer is a contact surface between the noise reduction blanket and the outer surface of the noise source, the flexible layer, the damping layer, the honeycomb layer and the gas-liquid mixing layer are sequentially arranged adjacently, the vibration absorption column is arranged in the damping layer, and the vibration absorption column is cylindrical, conical or strip-shaped.
The noise reduction device for the on-site maintenance of the gas turbine provided by the invention has the following technical characteristics:
further, the top end of the vibration absorption column is provided with a balancing weight.
Further, the damping layer is filled with liquid.
Further, the gas-liquid mixing layer is a gas-liquid mixing filling layer.
Further, the flexible layer, the damping layer, the honeycomb layer and the gas-liquid mixing layer are arranged in a sealing manner.
Further, an active noise reduction system is arranged in the surrounding area of the noise reduction blanket, the active noise reduction system comprises a playing system, a sensor system and an audio analysis system, the playing system outputs sound waves with the same amplitude and opposite phases with the noise source, and the playing system outputs sound waves with the same amplitude and opposite phases with the noise source.
Further, the playing system and the sensor system are arranged on the noise reduction ring.
Further, the noise reduction ring is arranged on a tracking system, and the tracking system comprises a chassis, a rotating mechanism and an identification module.
Further, the noise reduction rings are arranged in pairs and are arranged in pairs.
Further, the outer surface of the noise source comprises the ground, the outer surface of the gas turbine and the wall surface.
The invention has the following beneficial effects: the following points are combined with the specific technical means:
1. the invention forms the noise-reducing blanket for noise-reducing covering through the gas-liquid mixing layer, the honeycomb layer, the damping layer and the flexible layer, is convenient to use, only needs to be arranged on the surface of a noise source for noise reduction and the conducting surface, wherein the flexible layer enables the noise-reducing blanket to be attached to the noise surface or covers and surrounds the transmission surface of the noise source, the flexible layer is utilized to guide the vibration wave transmitted by the noise into the damping layer, the vibration absorbing column is utilized to carry out resonance and absorption of vibration, and then the friction vibration between the vibration absorbing column and the damping layer is utilized to form a passive technical measure for noise attenuation.
2. The gas-liquid mixing layer, the honeycomb layer, the damping layer and the flexible layer have different transmission speeds of sound waves by using different media, and refraction, reflection and diffraction occur on the transmission section, so that the gas-liquid mixing layer, the honeycomb layer, the damping layer and the flexible layer can be effectively attenuated, and noise can be rapidly attenuated by using variable-density transmission media.
3. The invention aims at a working area or space of maintenance personnel, and can collect sound wave signals of a noise source in a field space through an active noise reduction system, analyze the sound wave signals to obtain phases, amplitudes and the like, and then output sound waves with opposite phases and close amplitudes through a playing system to offset the sound waves, so that the purposes of noise elimination and noise reduction are achieved in a designated area.
4. The invention also considers that the tracking system is used for carrying out enhancement operation on the space area needing noise reduction, for example, under the condition that a maintainer walks, the core of the required noise reduction area is dynamically changed, only the maintainer or the required tracking label is required to be set, the identification module is used for tracking the label, and then the rotary mechanism is driven in a conversion mode, so that dynamic tracking is realized, the effect is good, the noise reduction problem of the dynamic area can be solved, the noise reduction requirement of the dynamic designated space is met, and the safe operation space is provided to the greatest extent.
Drawings
FIG. 1 is a cross-sectional view of a noise abatement blanket of a noise abatement device for gas turbine field maintenance in accordance with an embodiment of the present invention;
FIG. 2 is a top view of a pair of noise reduction rings of a noise reduction device for on-site maintenance of a gas turbine in accordance with an embodiment of the present invention;
FIG. 3 is a front view of a noise reduction ring of a noise reduction device for field maintenance of a gas turbine in accordance with an embodiment of the present invention;
FIG. 4 is a system schematic diagram of an active noise reduction system of a noise reduction device for on-site maintenance of a gas turbine according to an embodiment of the present invention;
in the figure: 1. the device comprises a gas-liquid mixing layer 2, a honeycomb layer 3, a vibration absorption column 4, a flexible layer 5, a damping layer 6, a noise reduction ring I7, a playing system I8, a sensor system I61, a noise reduction ring II 71, a playing system II 81 and a sensor system II.
Detailed Description
The invention will be described in detail hereinafter with reference to the drawings in conjunction with embodiments. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
The noise reduction device for on-site maintenance of the gas turbine comprises a noise reduction blanket, wherein the noise reduction blanket is arranged on the outer surface of a noise source and at least comprises a gas-liquid mixing layer 1, a honeycomb layer 2, a vibration absorption column 3, a flexible layer 4 and a damping layer 5, the flexible layer 4 is a contact surface between the noise reduction blanket and the outer surface of the noise source, the flexible layer 4, the damping layer 5, the honeycomb layer 2 and the gas-liquid mixing layer 1 are sequentially arranged adjacently, the vibration absorption column 3 is arranged in the damping layer 5, and the vibration absorption column 3 is cylindrical, conical or strip-shaped.
When the invention is implemented, the implementation key points are as follows:
1. the noise-reducing blanket for noise reduction and coverage is formed by the gas-liquid mixing layer 1, the honeycomb layer 2, the damping layer 5 and the flexible layer 4, is convenient to use, is only required to be arranged on the surface of a noise source for noise reduction and the conducting surface, wherein the flexible layer 4 enables the noise-reducing blanket to be attached to the noise surface or covers and surrounds the transmission surface of the noise-reducing blanket, the vibration wave transmitted by the noise is guided into the damping layer 5 by the flexible layer 4, resonance and vibration absorption are carried out by the vibration absorption column 3, and then friction vibration between the vibration absorption column 3 and the damping layer 5 is utilized, so that a passive technical measure for noise reduction is formed.
2. The gas-liquid mixing layer 1, the honeycomb layer 2, the damping layer 5 and the flexible layer 4 have different transmission speeds of sound waves by using different media, and refraction, reflection and diffraction occur on the transmission section, so that the gas-liquid mixing layer is effectively attenuated, and the noise is rapidly attenuated by using the variable-density transmission media.
3. The invention aims at a working area or space of maintenance personnel, and can collect sound wave signals of a noise source in a field space through an active noise reduction system, analyze the sound wave signals to obtain phases, amplitudes and the like, and then output sound waves with opposite phases and close amplitudes through a playing system to offset the sound waves, so that the purposes of noise elimination and noise reduction are achieved in a designated area.
4. The invention also considers that the tracking system is used for carrying out enhancement operation on the space area needing noise reduction, for example, under the condition that a maintainer walks, the core of the required noise reduction area is dynamically changed, only the maintainer or the required tracking label is required to be set, the identification module is used for tracking the label, and then the rotary mechanism is driven in a conversion mode, so that dynamic tracking is realized, the effect is good, the noise reduction problem of the dynamic area can be solved, the noise reduction requirement of the dynamic designated space is met, and the safe operation space is provided to the greatest extent.
In an embodiment of the present application, the top of the shock absorbing column 3 be provided with the balancing weight, utilize balancing weight increase absorbing vibration energy, increase damping friction consumption's stored energy simultaneously, the noise reduction effect is stable, lasts effectually.
In one embodiment of the present application, the damping layer 5 is filled with a liquid, which may be a mixture of water, oil, or the like, or a single substance, and has a high viscosity.
In one embodiment of the present application, the gas-liquid mixing layer 1 is a gas-liquid mixing filling layer, and the purpose of reducing noise and blocking the propagation of sound waves is achieved by using gas-liquid mixing, so that the sound waves are rapidly attenuated after multiple reflection and refraction.
In an embodiment of the application, the flexible layer 4, the damping layer 5, the honeycomb layer 2 and the gas-liquid mixing layer 1 are arranged in a sealing manner, so that each layer works independently, the service life is long, the structure is firm and durable, the effect is good, the sound insulation effect is optimal through combination of multiple layers, the noise source is covered by a single layer of material through test detection, and the attenuation data before and after detection are as follows:
| monolayer of | Flexible layer | Damping layer | Honeycomb layer | Gas-liquid mixing layer |
| Damping ratio | 3-5% | 6-8% | 15-20% | 20-25%% |
The multi-layer composite attenuation data were used as follows:
therefore, the invention is created and is the best choice, because the sound wave propagates with its own characteristics, the propagation speed of solid and liquid is high, but there is reflection and refraction after passing through different media, and the attenuation is high, therefore, the flexible layer and the damping layer are used for fast guiding, the noise source enters the noise blanket, the honeycomb layer and the gas-liquid mixing layer are used for fast attenuation, and the gas-liquid mixing layer is arranged at the outermost layer for convenient manufacture and maintenance.
The damping layer 5 is internally provided with a vibration absorption column 3, and the effects of the damping layer are compared as follows through single-layer attenuation data test:
| monolayer of | Damping layer (without shock-absorbing column) | Damping layer (with shock-absorbing column) | Damping layer (vibration absorbing column with balancing weight) |
| Damping ratio | 3-5% | 6-8% | 9-12% |
Therefore, the added vibration absorbing column has obvious noise reduction effect, the balancing weight is added, and the vibration absorbing effect is better, because the absorbed kinetic energy is utilized for energy reduction.
In an embodiment of the present application, the surrounding area of the noise-reducing blanket is provided with an active noise-reducing system, the active noise-reducing system includes a playing system, a sensor system, an audio analysis system, the noise-reducing effect is good, the cost is low, and the noise-reducing blanket has the characteristics of specifying an area and reducing noise rapidly.
In an embodiment of the application, the playing system and the sensor system are arranged on the noise reduction ring, so that the structure is simple, the adjustment is convenient, and the regional noise reduction effect is good.
In one embodiment of the application, the noise reduction ring is arranged on a tracking system, and the tracking system comprises a chassis, a rotating mechanism and an identification module, so that the noise reduction of a designated area can be dynamically tracked.
In an embodiment of the application, the noise reduction rings are arranged in pairs and are arranged in pairs, so that the noise reduction effect is enhanced, the operation is convenient, the directivity is high, and the safety of field personnel is guaranteed.
In an embodiment of the application, the noise source outer surface comprises the ground, the gas turbine outer surface and the wall surface, and the application range is wide, the effect is good, and the cost is low.
As shown in fig. 2 and fig. 3, the pair of noise reduction ring structures provided for the present invention are provided in pairs, and the noise reduction ring I6, the playing system I7, the sensor system I8, the noise reduction ring ii 61, the playing system ii 71, and the sensor system ii 81 are utilized to form the pair of noise reduction ring structures, so that the sensor system and the playing system can be synchronized by considering the arrangement of the synchronous switch, and the tracking signal distortion and the internal feedback loop noise caused by the time delay can be avoided.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. The utility model provides a gas turbine on-the-spot maintenance is with device of making an uproar which falls which characterized in that: the noise reduction blanket is arranged on the outer surface of a noise source and at least comprises a gas-liquid mixing layer (1), a honeycomb layer (2), a vibration absorption column (3), a flexible layer (4) and a damping layer (5), wherein the flexible layer (4) is a contact surface between the noise reduction blanket and the outer surface of the noise source, the flexible layer (4), the damping layer (5), the honeycomb layer (2) and the gas-liquid mixing layer (1) are sequentially arranged adjacently, the vibration absorption column (3) is arranged in the damping layer (5), and the vibration absorption column (3) is cylindrical, conical or strip-shaped;
the flexible layer (4) and the damping layer (5) are used for rapidly guiding a noise source into the noise blanket, and the honeycomb layer (2) and the gas-liquid mixing layer (1) are used for attenuating the noise;
the top end of the vibration absorption column (3) is provided with a balancing weight.
2. The noise reduction device for on-site maintenance of a gas turbine according to claim 1, wherein: the damping layer (5) is filled with liquid.
3. The noise reduction device for on-site maintenance of a gas turbine according to claim 1, wherein: the gas-liquid mixing layer (1) is internally provided with a gas-liquid mixing filling layer.
4. The noise reduction device for on-site maintenance of a gas turbine according to claim 1, wherein: the flexible layer (4), the damping layer (5), the honeycomb layer (2) and the gas-liquid mixing layer (1) are arranged in a sealing manner.
5. The noise reduction device for on-site maintenance of a gas turbine according to claim 1, wherein: the active noise reduction system comprises a playing system, a sensor system and an audio analysis system, wherein the playing system outputs sound waves with the same amplitude and opposite phases with the noise source.
6. The noise reduction device for on-site maintenance of a gas turbine according to claim 5, wherein: the playing system and the sensor system are arranged on the noise reduction ring.
7. The noise reduction device for on-site maintenance of a gas turbine according to claim 6, wherein: the noise reduction ring is arranged on a tracking system, and the tracking system comprises a chassis, a rotating mechanism and an identification module.
8. The noise reduction device for on-site maintenance of a gas turbine according to claim 6, wherein: the noise reduction rings are arranged in pairs and are arranged in pairs.
9. The noise reduction device for on-site maintenance of a gas turbine according to claim 1, wherein: the outer surface of the noise source comprises the ground, the outer surface of the gas turbine and the wall surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110882578.4A CN113628605B (en) | 2021-08-02 | 2021-08-02 | Noise reduction device for on-site maintenance of gas turbine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110882578.4A CN113628605B (en) | 2021-08-02 | 2021-08-02 | Noise reduction device for on-site maintenance of gas turbine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113628605A CN113628605A (en) | 2021-11-09 |
| CN113628605B true CN113628605B (en) | 2024-03-12 |
Family
ID=78382203
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110882578.4A Active CN113628605B (en) | 2021-08-02 | 2021-08-02 | Noise reduction device for on-site maintenance of gas turbine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113628605B (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5554830A (en) * | 1990-07-19 | 1996-09-10 | Matec Holding Ag | Noise-reducing covering for vehicle interior |
| CN201970936U (en) * | 2010-11-22 | 2011-09-14 | 浙江吉利汽车研究院有限公司 | Vibration damping and noise reduction gasket structure used for automobile |
| CN205100602U (en) * | 2015-03-25 | 2016-03-23 | 周辉 | Structure of making an uproar falls in diesel generator room |
| KR20170013794A (en) * | 2015-07-28 | 2017-02-07 | 연세대학교 산학협력단 | Broadband acoustic absorption plate using broadband acoustic metamaterial unit element |
| CN206179506U (en) * | 2016-11-11 | 2017-05-17 | 马彦亭 | Device is subductd to unmanned aerial vehicle noise |
| CN109686355A (en) * | 2018-12-28 | 2019-04-26 | 杭州静之源噪声控制技术有限公司 | Full rate baffle |
| JP2019159210A (en) * | 2018-03-15 | 2019-09-19 | 岡野 健 | Noise-reducing method and device |
| CN211080635U (en) * | 2019-11-15 | 2020-07-24 | 苏州铂韬新材料科技有限公司 | Sound insulation wave absorbing plate |
| CN213675772U (en) * | 2020-10-22 | 2021-07-13 | 中车青岛四方机车车辆股份有限公司 | Sound insulation floor |
-
2021
- 2021-08-02 CN CN202110882578.4A patent/CN113628605B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5554830A (en) * | 1990-07-19 | 1996-09-10 | Matec Holding Ag | Noise-reducing covering for vehicle interior |
| CN201970936U (en) * | 2010-11-22 | 2011-09-14 | 浙江吉利汽车研究院有限公司 | Vibration damping and noise reduction gasket structure used for automobile |
| CN205100602U (en) * | 2015-03-25 | 2016-03-23 | 周辉 | Structure of making an uproar falls in diesel generator room |
| KR20170013794A (en) * | 2015-07-28 | 2017-02-07 | 연세대학교 산학협력단 | Broadband acoustic absorption plate using broadband acoustic metamaterial unit element |
| CN206179506U (en) * | 2016-11-11 | 2017-05-17 | 马彦亭 | Device is subductd to unmanned aerial vehicle noise |
| JP2019159210A (en) * | 2018-03-15 | 2019-09-19 | 岡野 健 | Noise-reducing method and device |
| CN109686355A (en) * | 2018-12-28 | 2019-04-26 | 杭州静之源噪声控制技术有限公司 | Full rate baffle |
| CN211080635U (en) * | 2019-11-15 | 2020-07-24 | 苏州铂韬新材料科技有限公司 | Sound insulation wave absorbing plate |
| CN213675772U (en) * | 2020-10-22 | 2021-07-13 | 中车青岛四方机车车辆股份有限公司 | Sound insulation floor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113628605A (en) | 2021-11-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108133700A (en) | A kind of acoustics black hole vibration and noise reducing device | |
| EP1715158A3 (en) | Duct liner acoustic splice | |
| CN113628605B (en) | Noise reduction device for on-site maintenance of gas turbine | |
| CN108279579B (en) | A kind of Large Underwater platform noise reduction system with class cochlear structures | |
| CN210714982U (en) | Vibration and noise reduction device for air energy heat pump | |
| CN205487329U (en) | Pad pasting of making an uproar falls | |
| CN103469909A (en) | Sound-absorbing wedge | |
| CN205178284U (en) | Structure of making an uproar is fallen based on foamed aluminium metal reduces city transformer substation low -frequency noise | |
| CN109945680A (en) | Cooling tower with silencer | |
| CN205502292U (en) | Syllable -dividing wall of making an uproar falls | |
| CN201035981Y (en) | Device of reducing noise | |
| CN103397712B (en) | Anechoic room transmission shaft sound-insulating structure | |
| Kastelein et al. | Hearing thresholds of a harbor porpoise (Phocoena phocoena) for helicopter dipping sonar signals (1.43–1.33 kHz)(L) | |
| CN212582673U (en) | Hammer carrier of hydraulic hammer with noise reduction device | |
| CN203201808U (en) | Roots blower pipeline noise reduction device | |
| CN106087611B (en) | Rail traffic component | |
| CN210110336U (en) | Inhale sound and fall dryer of making an uproar | |
| CN209673997U (en) | It is a kind of for detecting the underwater sonar detection device of target property | |
| CN208634305U (en) | A kind of denoising device of globoid cam high speed and precision divider | |
| CN217381044U (en) | Air inlet silencer of mining local axial flow fan | |
| CN205230579U (en) | Compound noise eliminator in ventilation tunnel | |
| Ng et al. | Classification and noise correlation of local anthropogenic noise sources in Oklahoma. | |
| CN217061425U (en) | Regional resonance noise reduction equipment | |
| CN211236800U (en) | Computer comprehensive noise reduction device | |
| CN105118495A (en) | Factory noise absorber |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |