The function of a muffler.
A vehicle muffler is an effective external transmission device for controlling aerodynamic noise. Through internal structural acoustic treatment, the generation and propagation of noise can be greatly reduced without affecting the passage of airflow. After the muffler is assembled, the noise reduction should reach 20-40dB (A), with a subjective decrease of 50-90%.
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Secondly, the types of car mufflers.
1. Resistance type car mufflers have the characteristics of absorbing mid to high frequency sounds and being easy to manufacture. They are usually suitable for eliminating noise in fans, compressors, gas turbines, blowers, and other fan types.
2. Anti muffler has the characteristics of strong targeting, significant sound absorption effect at medium and low frequencies, and no sound absorbing materials. Usually only suitable for noise reduction in exhaust pipes of small pipelines, such as cars, ships, diesel engines, etc.
3. The characteristic impedance muffler has the characteristics of noise reduction bandwidth and reliable use. Mainly suitable for eliminating mid frequency broadband network noise with high sound level but low frequency. Such as steam turbine, deaerator, expansion vessel, small displacement safety valve, etc.
4. The small circular hole muffler has low to medium frequency broadband network noise reduction characteristics. The small aperture can improve the sound absorption coefficient, the low porosity can increase the width of the sound absorption band, and the depth of the orifice plate can change the position of the resonance sound absorption peak. This utility model has excellent design scheme, wide absorption frequency band, low impedance loss, high temperature resistance, and long service life. Usually suitable for exhaust pipes of high-pressure equipment such as boilers and compressors.
5. The anti spray resistance composite muffler has the advantages of noise reduction bandwidth, wide application range, large noise reduction amount, high temperature and high pressure resistance, and is not afraid of water vapor and oil mist. It was successfully developed based on the noise reduction theory of motor small circular hole jet by Chinese acoustics experts. At present, various power plants are commonly used for structural exhaust mufflers in China.
6. The through-hole anti dispersion muffler has the advantages of smooth exhaust pipe, high temperature resistance, and strong anti-interference ability. Usually suitable for safety valves, exhaust valves, turbine and blowpipe exhaust pipes, and noise reduction.
Thirdly, the evaluation of the muffler.
There are two aspects to evaluating the characteristics of a muffler: aerodynamic characteristics and noise reduction characteristics. In other words, the pressure loss of the muffler must be within the allowable limit range and must meet the requirements of noise standards. Therefore, when choosing a muffler, aerodynamic and noise reduction characteristics should be considered, which are essential.
Fourth, the selection of mufflers.
When selecting a fan muffler, users should submit the type of fan (including fan, fan, Roots fan, axial fan, air compressor, etc.). ）And provide the inlet and outlet dimensions and air volume of the fan. Usually, fan mufflers are assembled at the entrance and exit, and the fan muffler should be treated comprehensively, that is, the muffler and muffler chamber should be assembled together. The shell of the fan muffler is made of carbon steel, and the internal structural raw materials are divided into aluminum plate and stainless steel. Users can choose according to cost.
When selecting a boiler steam discharge muffler, users should provide the hourly consumption, discharge inlet and outlet dimensions, discharge temperature, and pressure. Exhaust mufflers are usually selected as spray resistant composite car mufflers, with a carbon steel shell and stainless steel pipes and internal structural materials. They have the advantages of wide noise reduction bandwidth, wide application range, high noise reduction capacity, high temperature and high pressure resistance, and are not afraid of water vapor and oil mist. Small circular hole jet mufflers can also be used, usually made of all stainless steel.
3. Blow pipe mufflers must be suitable for harsh office environments, where the working medium may contain water, iron impurities (particle size up to 30 millimeters), engineering residues, etc. Users should provide consumption, exhaust port size, exhaust pipe temperature, and unit model specifications. Blow tube mufflers are usually selected as through-hole type dispersion mufflers, with carbon steel pipes and shells, and stainless steel internal structural raw materials. They are usually disposable and can be designed multiple times according to user requirements. Additionally, it can be recycled after use.
4. The steam discharge from the safety valve is a sudden and instantaneous discharge. When designing a safety valve muffler, consideration should be given to smooth discharge without throttling. Users should provide safety valve discharge, steam inlet and outlet dimensions, steam discharge temperature, and jump pressure. The safety valve exhaust muffler usually uses a through-hole diffusion muffler, with a carbon steel shell and stainless steel pipes and internal structural materials. Small circular holes can also be used to spray mufflers, provided that the consumption is large enough to avoid pressure suppression and throttling. Generally, all stainless steel is selected.
