Silencing pipe Noise reduction classification

1. Resistive muffler: It absorbs sound energy and reduces noise by attaching sound absorbing materials in the box, and is generally used to eliminate high and intermediate frequency noise. However, due to the structure, it is not applicable to high temperature, high humidity and high speed.

2. Anti muffler: It silences noise by changing the cross section. This principle applies to the commonly used silencing static pressure box. Generally, it can reduce medium and low-frequency noise, and has no specific requirements for the wind system.

3. Impedance compound type: of course, it combines the structural principle of the two. It can eliminate low, medium and high frequency noise. However, the requirements for the air system are the same as for the resistive muffler. The dissipative muffler has good noise elimination performance at medium and high frequencies. According to the different geometric shapes of air flow channels, it can be divided into straight pipe type, sheet type, folded plate type, labyrinth type, honeycomb type, acoustic flow type, baffle type, elbow type, etc. The reactive muffler is suitable for eliminating medium and low frequency noise or narrow band noise. According to the different working principles, it can be divided into expansion type, resonant cavity type and interference type. Impedance compound muffler, with resonance cavity, expansion chamber, perforated screen and other acoustic filtering devices, combines the good middle and high frequency noise elimination characteristics of resistive muffler and the good low-frequency noise elimination characteristics of impedance muffler, so its noise elimination frequency band is wide, and it is one of the commonly used standard muffler series. The suitable wind speed is 6-8m/s, and the height can reach 8-12m. It can be used alone or in series. Noise elimination effect: low frequency 10~15dB/m, medium frequency 15~25dB/m, high frequency 25~30dB/m, average resistance coefficient 0.4. According to Air Conditioning, silencing elbow and silencing static pressure box belong to a kind of silencer.

Static pressure box action

1. Part of the dynamic pressure can be changed into static pressure to make the wind blow farther;

2. It can reduce noise;

3. Uniform distribution of air volume;

4. The static pressure box can be used to reduce noise, obtain uniform static pressure air outlet, and reduce dynamic pressure loss. It also has the function of universal joint. The application of static pressure box in ventilation system can improve the comprehensive performance of ventilation system.