Measures to reduce the noise of the exhaust port of the variable-frequency air compressor

To control the intake noise of an air compressor, a muffler can generally be installed. Since the noise at the air compressor inlet is of low frequency characteristics, a resistant muffler should be used. The resistant muffler is a muffler that reflects part of the sound wave back to the direction of the sound source through the sudden change of the acoustic characteristics in the pipeline to achieve the purpose of sound elimination. The frequency conversion air compressor is mainly suitable for reducing the noise of low frequency and low and middle frequency bands. Its forms are: expansion type, resonance type, expansion chamber type and so on.

Stationary air compressors are usually installed on the indoor floor, but some of the air inlets of the air compressor are indoors and some are outdoors. When the air compressor air inlet is indoors, the noise of the air inlet should be reduced to slightly lower than the noise of the machine body. The sound attenuation of the air inlet muffler should be about 15dB(A); when the air compressor air inlet is outdoors, According to the environmental conditions around the machine room, the air compressor air inlet noise should be reduced to the requirements of the environmental noise standard. The sound attenuation of the muffler should generally be above 20dB (A).

In order to ensure the silencing effect of the muffler, the air intake muffler should generally adopt a resistant muffler without loose materials such as fiber and foam, a resistant micro-perforated plate composite muffler or a micro-perforated plate muffler. A common air compressor intake resistant muffler is to open some uniform small holes on a section of the pipe wall of the air inlet, and connect a closed cavity 3-4 times the diameter of the section of the pipe. The hollow air column in the small hole and the cavity form a common vibration system. At the resonance frequency, the air column vibrates at a high speed, which overcomes the frictional resistance and consumes a large amount of sound energy, forming a resistive resonance with a low-frequency sound reduction effect.

Some air compressors are equipped with an air filter at the air inlet. The air filter has a certain attenuation of airflow noise at the air inlet, but it cannot meet the noise reduction requirements, so it is still necessary to add a muffler device. Generally, the steel frame of the filter can be used to set up silencing louvers for noise reduction. The silencing louvers are made of aluminum alloy plates, mainly for rust prevention; the louvers are vertical, which is good for dust prevention; sound absorption in the silencing louvers Hollow glass wool is used as the material, which has good sound absorption performance and is a water-repellent material, suitable for outdoor use.