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National diesel generator set noise treatment scheme
- 2019-03-13-
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     Domestic diesel generator set noise reduction The principle is to reduce the noise of the intake, exhaust and exhaust systems under the premise of ensuring the ventilation conditions of the diesel generator set, that is, without reducing the output power, using sound absorbing materials and noise reduction and noise reduction devices. The noise emission is up to the Chinese standard (85dB(A)). The basic method of noise reduction of generators is to start from the sound source, and adopt conventional noise reduction techniques such as muffler, sound insulation, sound absorption and vibration isolation, which is a more effective method.

     1. Reduce exhaust noise. Exhaust noise is the main source of noise for the unit. It is characterized by high noise, fast exhaust speed and difficult control. The use of a special impedance composite muffler reduces exhaust noise by 40-60dB(A).

     2. Reduce the noise of the axial fan. There are two issues to consider when reducing the noise of the genset cooling fan. One is the pressure loss allowed by the exhaust passage. Then there is the desired silence level. In view of the above two points, a resistive patch muffler can be selected.

     3. Sound insulation, sound absorption treatment and vibration isolation of the machine room

    (1) Sound insulation in the engine room. After the domestic diesel generator set exhaust noise and cooling fan noise are reduced, the other major noise sources are diesel machine mechanical noise and combustion noise. The method used is to remove the window outside the inner wall viewing window required to connect to the observation room. The hole should be tightly sealed. Brick wall sound insulation should be greater than 40dB (A). The engine room is equipped with fireproof and soundproof windows and doors.

    (2) Intake and exhaust. After the cabin is soundproofed, it solves the problem of ventilation and heat dissipation in the cabin. The intake air should be placed on the same line as the generator set and the exhaust port. The air inlet should be equipped with a resistive vane silencer. Since the pressure loss of the air inlet is within the allowable range, the airflow in and out of the cabin is naturally balanced, and the ventilation and heat dissipation effect is obvious.

    (3) Sound absorption treatment. The five walls in the cabin except the ground can be used for sound absorption. According to the spectral characteristics of the generator set, a perforated plate resonant sound absorbing structure is adopted.

    (4) When the closed water-cooled generator set is shut down, the exchange of indoor air and sound insulation in the engine room will cause the indoor air to not convect, and the indoor high temperature cannot be lowered in time. This problem can be solved by using a low-noise axial fan and an added resistive muffler.

    (5) Unit vibration isolation. Before the installation of domestic diesel generator sets, vibration isolation should be carried out in strict accordance with the relevant information provided by the manufacturer to avoid long-distance transmission of structural sounds, and the airborne sound should be continuously radiated during the transmission process, so that the noise level at the boundary of the plant is not up to standard. For existing generator sets that need to be processed due to excessive standards, ground vibrations near the generator set must be measured. If the vibration feels obvious, the domestic diesel generator set should be firstly isolated.