An effective way to reduce the noise of an air compressor?
Views : 648
Author : Runningway
Update time : 2021-08-09 14:39:16
Air compressors play an important role in production, but air compressors are a kind of equipment with strong noise. The noise of the air compressor mainly comes from the four parts of the air inlet, the exhaust port, the mechanical port and the electromagnetic port. The air compressor has high noise level, prominent low frequency, long transmission distance and large pollution range. In particular, the frequency of certain noises is close to the natural frequency of human internal organs, causing resonance, causing people to produce dizziness, nausea, tachycardia, high blood pressure and other stereotypes, not only leading to people’s work and life quality degradation, but also easy to cause Safety accidents and conflicts in interpersonal relationships.
Therefore, the control of air compressor noise is not only an important issue for labor protection and environmental protection, but also an important issue for the sustainable and healthy development of production enterprises. Therefore, reducing air compressor noise and noise control are particularly important. We know that the noise of the air compressor mainly comes from the four parts of the air inlet, the exhaust port, the mechanical port, and the electromagnetic port. Therefore, we can reduce the noise of the air compressor as long as the noise control of these four parts is carried out. From the air compressor inlet noise control, air compressor exhaust noise control, air compressor body noise control, air compressor body vibration and noise control respectively.
1. Reduce the noise of the air compressor inlet
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. Mainly suitable for reducing noise in low frequency and low and mid frequency bands. Its forms are: expansion type, resonance type, expansion chamber type, micro-perforated plate type, interference 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 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 inlet is outdoors, According to the environmental conditions around the engine room, the air compressor inlet noise should be reduced to the requirements of the environmental noise standard. The noise reduction 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 inlet resistant muffler is to open some uniform small holes on the pipe wall of the air inlet, and connect a closed cavity 3-4 times the diameter 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 attenuates the airflow noise at the air inlet to a certain extent, 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 sound attenuation. 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.
2. Reduce exhaust noise of air compressor
Air compressors with high exhaust pressure and large flow rate produce high exhaust noise, so a dedicated muffler must be installed in the exhaust system for control. The exhaust muffler requires a large amount of sound attenuation, a wide range of sound attenuation, and has the function of decompression and expansion, reducing the pressure drop of the exhaust venting, and reducing the exhaust venting noise. For air compressors with a flow rate of less than 20m3/min, the noise is not high and mainly high frequency, generally resistive muffler can be used. The advantage of the resistive muffler is that it can muffle sound in a wide medium and high frequency range, especially for high-frequency sound waves. The resistive muffler uses different structural forms of porous sound-absorbing materials (often called resistive materials) in the airflow duct to absorb sound energy and reduce noise. The wide muffling frequency range is especially remarkable in the middle and high frequency range. There are several types of resistive mufflers: tube muffler, elbow muffler, small chamber muffler, disc muffler.
But for the air compressor with high exhaust pressure and large flow rate, due to the large noise sound pressure level, there are both medium and low frequency noise and high frequency noise. The effect of resistive muffler alone is not ideal. Compound muffler can solve the problem. Effective ways, the forms of compound muffler are: impedance compound type, resistive and resonance compound type, resistance and micro-perforated plate compound type, etc. The compound muffler combines the previous advantages. Although the resistive muffler has excellent mid-to-high frequency muffling performance, the low-frequency muffler performance is poor and difficult to improve, while the expansion type and resonance type muffler are on the contrary. Good silencing performance, high-frequency silencing effect is generally poor. If the two sound-absorbing principles of resistance and resistance are combined into a muffler, a satisfactory sound-absorbing effect can be obtained in a wide frequency range. The muffler has acoustic filter elements such as a resonance cavity, an expansion chamber, a perforated screen, etc., and has a sound-absorbing material with holes, which has a sound-absorbing effect on noises of different frequencies.
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