1. Noise reduction project of large fan of Sichuan Lutianhua Co., Ltd. I. General situation of the project

Sichuan Lutianhua Co., Ltd., located in Luzhou, the hometown of famous wines in China, is the first enterprise in China to produce synthetic ammonia and urea from natural gas by using western technology. Sichuan Lutianhua Co., Ltd., as a well-known enterprise in the international fertilizer industry, is the oldest and largest urea producer in China, and a state-owned backbone enterprise in Sichuan Province, with total assets of nearly 4 billion yuan and annual sales income of more than 3 billion yuan. It is a large-scale comprehensive enterprise integrating production, scientific research, development, design and trade.

The air separation building of Lutianhua Co., Ltd. is equipped with four axial flow fans for urea granules. The high noise generated by the operation of fans and their supporting equipment affects the work and life of residents in this area through air transmission. Through field monitoring, the noise at the fan reaches 1 17dB(A), and the noise at the residential building outside the factory boundary also reaches about 65dB(A). In order to effectively control noise, improve the acoustic environment of residential areas and factory areas, and make the noise at the boundary of the factory reach the third-class standard specified in GB 12348-2008 Noise Emission Standard for Industrial Enterprises (≤65dB(A) during the day and ≤55dB(A) at night), at the request of Lutianhua Co., Ltd., our company has comprehensively treated its noise.

Second, the project implementation

At the request of Party A, a step-by-step management method was adopted. In other words, the mechanical noise of the main body of the seven-story fan should be treated first, and then the noise reduction measures should be taken for the eight-story exhaust outlet.

1, seven-layer treatment measures

Combined with the existing steel skeleton of the air separation building, sound absorption and insulation boards are set up to form a sound insulation room, and at the same time, access doors and ventilation and noise reduction systems are reserved. The implementation points are as follows:

The seven-story exposed facade of the air separator is closed with stainless steel composite sound insulation board.

Strong sound absorption structure is used indoors and on the top surface.

Set electric push-pull soundproof door

The intake muffler and exhaust muffler are designed in combination with the existing structure.

2, eight layers of governance measures

According to the spectrum analysis after implementation, the seven-layer treatment mainly solves the mechanical noise of the main body of the fan, while the broadband noise radiated by the outlet of the eight-layer fan still has a certain impact on the factory boundary. Due to the high outlet speed and large flow rate of the fan, the conventional muffler may cause excessive pressure loss and affect the efficiency of the unit, and the influence of secondary noise on the final treatment effect can not be ignored. Therefore, the anechoic chamber is selected at the outlet of the fan, and the exhaust air is led to the east side of the winnowing machine room, so as to achieve the expected noise control effect. The implementation points are as follows:

In order to ensure safety, a ventilation anechoic room was built on the eighth floor, and a special load calculation was carried out according to the local climate conditions.

Considering the medium type and acoustic design, the muffler partition is the same as the seven-layer structure, and the top surface is provided with a drag-reducing diffuser structure.

The exhaust port on the east side is equipped with a silencer.

Third, the effect after implementation

After the above treatment, the noise level of the air separation plant is greatly reduced. After testing, the noise values at night outside the factory boundary 1m are all below 55dB(A), the "howling" basically disappears, and the acoustic environment in the main office building of the factory has been greatly improved, achieving the dual goals of environmental protection and labor protection.

China Oil and Gas Booster Noise Reduction Workshop Project

China Petroleum and Natural Gas Co., Ltd. (China Petroleum Group for short) is the world's leading comprehensive energy company integrating upstream and downstream business of oil and natural gas, technical service of oil and gas field engineering, and manufacturing and supply of petroleum materials and equipment. The natural gas compressor room of Tazhong 4 booster station of China Oil and Gas First Construction Company is located in the production plant area, with production area and office area. The compressor room is a single building with three large natural gas compressors inside. Because the compressor will produce high noise when working, the noise is about 100dB(A). In order to ensure the good working environment and quiet surrounding environment of the unit, our company implemented a comprehensive noise control project.

After treatment, the noise in the air compressor room is reduced by 15dB, and the noise outside the machine room is reduced by 25dB.

Feng Chun Holding Motorcycle Manufacturing Company Laboratory Noise Reduction Project

I. Overview of the Project

The test center of the Second Engine Research Institute of Feng Chun Holding Group Hangqi Manufacturing Co., Ltd. is located in the northeast of Feng Chun factory. The building is a brick-concrete structure with * * floors and a total area of 240㎡, including test workshop, control room, exhaust tower, annex room, assembly room and office. The highest medium and high frequency noise generated during the operation of the test workshop can reach 140dB(A). In order to avoid the influence of noise on the control room staff and the surrounding environment during the test, our company was entrusted by Party A to implement a comprehensive noise reduction project for the test center.

Second, the project implementation

Under the condition that the noise of the noise source itself cannot be reduced, comprehensive measures such as sound insulation, sound absorption and noise elimination are taken according to the required noise reduction. The implementation points are as follows:

Install sound-absorbing and heat-insulating panels on the surrounding walls and the top of the test room;

The sound absorption and insulation board is designed according to the frequency characteristics of site noise, which not only has excellent sound absorption and noise reduction performance (NRC≥0.95), but also has good sound insulation performance. In addition, the 100mm air layer ("air spring") formed during installation greatly enhances the sound insulation effect of the original wall.

The entrance and exit doors of the laboratory and exhaust room are replaced with sound-proof doors;

The observation window between the control room and the laboratory is replaced by a soundproof window;

The top surface of the control partition wall adopts sound absorption treatment;

The resistive muffler is installed in the air inlet and exhaust chamber to form a chip muffler.

Because the high noise of the laboratory will be transmitted to the outside through the air inlet and air outlet, it is necessary to silence the air inlet and air outlet. The specific method is to install a resistive muffler between the air inlet and the exhaust duct, and convert acoustic energy into heat energy through the friction between air and porous sound-absorbing materials (often called resistive materials), so as to achieve the purpose of reducing noise. After calculation, under the premise of large air volume, considering the balance between noise reduction and airflow regeneration noise, the noise reduction layer is mixed with different thicknesses. It can not only achieve good noise elimination effect, but also control the airflow speed below 4m/s, which well suppresses the airflow regeneration noise.

Third, the effect after implementation

After the above treatment, the noise in the control room is controlled within 65dB(A), which achieves the purpose of improving the working environment of employees and is well received by Party A. ..

Customization project of test platform of Lillemausen Electric Technology Company

I. Overview of the Project

Lilly Semma is one of 60 wholly-owned subsidiaries of Emerson, a fortune 500 company in the world, and a subsidiary brand of Emerson's industrial automation business. The company is operated by Lilly Semma France, a subsidiary of Emerson Electric. The head office was established in France 19 19, with more than 8,700 employees and five major businesses in the world. China Company was established in Fuzhou on 1999. The modern factory newly built and put into operation in 2007 is located in Xuyi Electromechanical Park, Fuzhou City, Fujian Province, covering an area of nearly 76,000 square meters, and mainly engaged in three major businesses: generators, motors and reducers. At the request of Lelysenma Motor Technology (Fuzhou) Co., Ltd., our company provided three kinds of noise enclosures (350 kVA, 1000 kVA and 2250 kVA) for testing alternators.

Second, the project implementation

The design and construction of this testing room were implemented with reference to the technical documents of Lillesenma Company, and improvements were made during the implementation. The implementation points are as follows:

Sound insulation cover main body

Sound insulation cover steel structure frame

Internal and external sound insulation boards of sound insulation cover

Soundproof door of soundproof cover

Soundproof hood observation window

Functional components of sound insulation cover

Ventilation (air intake and exhaust) and noise elimination system of sound insulation cover

Electric opening and braking system of sound insulation cover

Steam-driven opening and braking system of sound insulation cover

Support beam arm in sound insulation cover

Lighting and other circuits in the soundproof enclosure

Haier Group Assembly Line Quiet Testing Room Customization Project

I. Overview of the Project

Haier is the first brand of white goods in the world. The second production line of refrigerator in Haier Industrial Park in Huangdao District is located in a large factory building, and the lowest noise of equipment in the factory building is 72 dB(A). In order to effectively detect the noise value of its refrigerator products, Haier entrusted our company to design and build a mute detection room for it.

Second, the project implementation

Because the detection operation is completed on the assembly line, it is required that the design of silent detection room should consider the convenience of product access and the guarantee of sound insulation performance. The implementation points of the test room are as follows:

A sound-absorbing and sound-insulating composite plate is used to make a sound-insulating cover;

Flexible damping vibration isolation treatment of sound insulation cover and ground

Sound-proof door capable of automatically opening

Three-layer insulating glass soundproof observation window

Ventilation silencing system

Third, the effect after implementation

After the completion of the project, the indoor noise value is 33dB(A), creating a good testing environment.

Customized project of NVH semi-anechoic room in Chongqing Qingshan industry

I. Overview of the Project

Chongqing Qingshan Industry Co., Ltd. is a subsidiary of China Changan Automobile Group Co., Ltd., which is the largest professional transmission manufacturer in China and one of the largest mini-car transmission manufacturers in the world. Mainly engaged in the research, development, production and sales of various automobile transmissions, with an annual output of more than 6,543,800 sets of various transmissions. In order to meet the research needs of NVH, Chongqing Qingshan Industrial Co., Ltd. entrusted our company to design and construct its NVH semi-anechoic room customization and noise control project in Chongqing Qinggang Economic Development Zone.

Second, the project implementation

This project is based on "background noise value is less than or equal to 20 dB; Design and construction shall be carried out according to the requirements of frequency ≤ 125Hz. After completion, Tsinghua University Building Environment Testing Center shall be entrusted to carry out testing according to GB/T6882- 1986 "Precision Method for Measuring Sound Power Level of Noise Sources by Sound Pressure Method" (now revised as GB/T6882-2008). The implementation points are as follows:

The double-layer sound insulation board on the top floor forms the structure of "room in the room".

Indoor five-sided 400×400×600mm sound-absorbing wedge

Double-layer soundproof door at the main entrance ("soundproof door")

Interlayer ventilation and noise elimination system (with electric sound insulation door)

Sound insulation treatment of cable trench

Necessary lighting, water supply and gas supply systems; Alarm monitoring system; Fire public system, etc.

Third, the effect after implementation

The background noise of semi-anechoic room is 16. 1dB(A), and the lower frequency limit 125Hz conforms to GB/T6882- 1986 "Precise Measurement Method of Sound Power Level of Noise Sources in Anechoic Room and Semi-anechoic Room" (now revised as GB/t6882-2006)

Wenzhou Sheng Qiang Petrochemical Mechanical Supercharger Matching Sound Insulation Cover

Wenzhou Sheng Qiang Petrochemical Machinery Co., Ltd. is a high-tech enterprise in Zhejiang Province, which integrates the design, manufacture and localization of compressor R&D, imported large and medium-sized compressor units. Our company provides customized services for its products, such as D4 14/D4 10 natural gas air cooler and P404 supercharger.

On the premise of meeting the normal operation of the unit, the sound insulation cover is mainly used to reduce the noise generated during the operation of the equipment and reduce the impact on the outside world. After installation, the actual measurement shows that the noise can be reduced by >: 25dB at 1m outside the sound insulation cover.