1. Ventilation duct resistance muffler: It absorbs sound energy and reduces noise by absorbing sound data inside the box. It is commonly used to eliminate high and intermediate frequency noise. However, it is not suitable for high temperature, high humidity and high speed because of the structure.
2. Reactor muffler: It is muffled by changing cross section. This is the principle of our commonly used silencing static pressure box. Normally, there is no detailed request for wind system to reduce medium and low frequency noise.
3. Impedance Compound: Of course, it is the construction principle of separating the two. It can eliminate low, medium and high frequency noise. But for the requirement of the air system, I personally think it is better to choose the impedance compound muffler for the ordinary civil air conditioning and ventilation system. Resistive silencer has good performance of medium and high frequency noise elimination. According to the geometrical shape of airflow passage, it can be divided into straight tube type, sheet type, folded plate type, labyrinth type, honeycomb type, acoustic flow type, baffle type, elbow type, etc.
Resistant mufflers are suitable for eliminating medium and low frequency noise or narrowband noise. According to its different principles, it can be divided into expansion type, resonant cavity type and intervention type. Impedance compound muffler has resonant cavity, expansion chamber, perforated screen and other acoustic filters. It combines the good middle and high frequency muffler characteristics and the good low frequency muffler characteristics of impedance muffler. Therefore, its muffling frequency bandwidth is one of the most commonly used standard muffler series.
Suitable for wind speed of 6-8 m/s, up to 8-12 m, can be used alone or in series. Acoustic attenuation effect: low frequency 10-15 dB/m, medium frequency 15-25 dB/m, high frequency 25-30 dB/m, uniform resistance coefficient 0.4. According to Air Conditioning, muffler elbow and muffler static pressure box belong to one kind of muffler. Muffler is a kind of installation which can not only allow air to pass through, but also effectively prevent or weaken the sound energy to spread outward.