How to choose Air Compressor muffler

As the noise source, the airflow noise in the painting workplace is not only caused by the centrifugal fan with the ventilation system , but also by the power source of painting or powder spraying, and the power is caused by the Air Compressor. This type of Air Compressor belongs to the exhaust pressure of 0.8 Piston or two-stage compression Air Compressor below MPa. The exhaust of the Air Compressor is conveyed to the point of use in a closed state through the air storage tank and compressed air pipeline, and the suction end of the Air Compressor becomes the main source of noise. Its noise is typical low-frequency noise, and its noise peak value is usually 63~250Hz, and the frequency band above 2000Hz is generally lower than the NR 85 curve, that is, below the allowable noise level. For this reason, when controlling the noise at the suction end of the Air Compressor, no measures should be taken for the high-frequency band, and only the noise in the frequency band below 2000 Hz needs to be controlled.

The control of the noise at the suction end of the Air Compressor is mainly based on the selection and design of a suitable muffler. This type of muffler should use a resistant expansion muffler, or an impedance composite muffler mainly based on an expansion muffler . The selection and design points of this type of muffler are as follows.

(1) Appropriate noise reduction capacity: After installing a muffler at the suction end of the Air Compressor, the noise can be reduced to slightly lower than the mechanical noise of the Air Compressor. At this time, the muffler is a suitable noise reduction , and the mechanical noise of the Air Compressor has not been reduced, there is no obvious benefit, and it is unreasonable .

A large number of measured data show that the mechanical noise of the power Air Compressor used for coating operations is 82~84dB(A), while the noise at the suction end is 94~98dB(A), so the suitable Should be 12~16dB(A).

(2) The resistance of the muffler: The resistance loss of the muffler is small, and the resistance increases, which will lead to an increase in the air regeneration noise and affect the muffler effect.

(3) The function of the muffler: the muffler also acts as an air filter.

(4) The structure of the muffler: simple structure, small size, easy assembly and disassembly.

There are already a series of mufflers at the suction end of power Air Compressors suitable for painting operations in CHINA. Among them XL type Air Compressor muffler has a better effect and meets the above four design points. The XL type Air Compressor muffler adopts a double-chamber resistant expansion muffler. The muffler of this type of structure has been calculated by computer for more than 300 structural schemes. The results show that the noise The ground is equal to the simple superposition of two single-cavity noise reduction volumes. Especially in the low frequency band, it has a large amount of noise reduction. Its frequency is below 63Hz, 125 Hz, 250 Hz and 500 Hz , and the noise reduction is respectively: 10.7 dB(A), 18.6 dB(A), 26.1 dB(A) and 15 dB(A), which can meet the requirements of the muffler. volume.

The two-chamber insertion tube of the XL muffler, through many tests, changed the straight tube type to the Venturi tube type, which can not only reduce the eddy current, avoid the increase of airflow noise, but also facilitate the reflection of sound waves and the attenuation . Practice shows that changing the insertion tube of the resistant expansion muffler from the straight tube type to the Venturi tube type can not only increase the noise reduction, but also help reduce the resistance loss of the muffler.

XL type mufflers are used for power of 10m³/min and 20m³ /min . The long-term use of the type Air Compressor shows that due to the different installation conditions and specific use places, the noise reduction is mostly 10~18 dB(A) , and the resistance loss does not exceed 1250 dB(A) .