Fan silencers, exhaust pipe silencers, and blower fan silencers share the same form and utilize the resistive sound absorption and noise reduction principle that is effective for mid to high-frequency broadband characteristics. They also incorporate the resistive sound attenuation principle that is beneficial for low to mid-frequency and pulsating characteristics, as well as micro-perforated silencers and impedance composite silencers.
Aerodynamic silencers for fans are categorized into: centrifugal fan silencers, Roots fan silencers, blower silencers, and axial flow fan silencers. These silencers are primarily used to reduce the aerodynamic noise at the outlets, ducts, and intake openings of various fans, as well as in enclosed machine rooms.
According to the different structural designs of wind turbine进出口, they are categorized into circular and rectangular structures.
(1) The circular structure is designed for circular air outlet connections, available in two types: A and B. Type A features flanges at both ends, directly connected to the pipeline (i.e., pipeline silencer). Type B has a flange on one end and an open-air vent on the other (can be equipped with a rain hat), suitable only for outdoor pipeline end fittings and closed机房 air intakes.
(2) The impedance silencing panels in circular structures are typically 100 mm or 150 mm thick, with a noise reduction of 15-30 dB. Under wind speeds of 5-12 m/s, they are suitable for air volumes ranging from 1000 to 50,000 m³/h. The structure employs two impedance silencing zones for high-frequency and low-frequency noise reduction, maximizing the broadening of the noise reduction frequency band [2].
Structural Principles
Based on actual testing of the noise sources from industrial fans of various types, the spectral characteristics data is used to determine the required amount of sound absorption at which frequencies for designing acoustic absorbers and fluid passages. Additionally, narrow rectangular channels with large acoustic material coatings are employed to enhance absorption. Furthermore, at high noise levels, the noise sources of the fans often have multiple spectral values, and the requirements for sound absorption vary for different frequency bands. Therefore, this series of ventilation pipe silencers and blower fan silencers are of impedance type, utilizing resistive structures for high and medium-frequency noise absorption and antiresonant structures for medium and low-frequency noise reduction. High-frequency and low-frequency acoustic absorption areas are also incorporated in the resistive channels to maximize the expansion of the sound absorption frequency range, achieving effective noise reduction.
Ventilation duct silencers and blower exhaust silencers are suitable for all types of centrifugal, axial, Roots blowers, and air compressors.
Scope of Application
Fans are a type of general mechanical equipment with a wide range of applications, essential in the production processes of various industries such as electricity, mining, machinery, metallurgy, and chemical engineering.
