one、windOverview of muffler:

The fan muffler, in the form of a drum induced draft fan muffler, adopts the principles of resistive sound absorption and noise reduction that have good effects on medium and high frequency broadband characteristics, as well as the principles of resistive sound reduction and noise reduction that have good effects on low, medium frequency, and pulsation characteristics, as well as micro perforated mufflers and resistive composite mufflers.Fan silencers are divided into centrifugal fan silencers, Roots fan silencers, blower silencers, and axial flow fan silencersThere are several types of fan silencers, including induced draft fan silencers, supply fan silencers, dust collection fan silencers, chimney silencers, etcA resistive muffler is an absorption type muffler, which is generally divided into straight pipe, sheet, folded plate, honeycomb, acoustic flow, labyrinth, and elbow types according to the structure of the airflow channel. A resistive muffler utilizes the frictional and viscous resistance of sound waves propagating through porous sound-absorbing materials to convert sound energy into heat energy and dissipate it, thereby achieving the purpose of noise reduction. It is a widely used type of muffler among all mufflers.

Resistance muffler has a different principle from resistive muffler in terms of noise reduction. It cannot directly absorb sound energy, but instead uses the interface or adjacent resonant cavity on the pipeline to reflect and interfere with certain frequency sound waves propagating along the pipeline at the interface, thereby achieving the purpose of noise reduction. It is divided into expansion chamber muffler and resonant muffler.

In practical noise control engineering, noise is mostly in the wideband. Therefore, resistive sound absorption and noise reduction structures are usually combined to control high-intensity wideband noise.

2、 Classification and purpose of fan silencers:

1: Centrifugal fan muffler:

Centrifugal fan silencers are mainly used in various series of high-pressure centrifugal ventilation fans to reduce aerodynamic noise such as air inlet and outlet. Their principle is developed based on the principle of sound blocking sheet. This type of silencer has excellent acoustic performance and good aerodynamic performance; Reasonably structured and easy to install, it is a high-capacity resistive honeycomb muffler The resistant section adopts a multi chamber resistant rubber straight pipe channel and a cross shaped sound absorbing sheet form, which provides sufficient noise reduction over a wide frequency range.

2: Roots blower silencer:

The Roots blower muffler is used to reduce the intake and exhaust noise of Roots blowers or blowers. It can also be used for noise reduction of exhaust pipes and other high-pressure fans. The Roots blower muffler has a simple structure, light weight, low consumables, beautiful shape, easy installation, and fire resistance. Under the same flow rate of the fan, this series of mufflers is also suitable for the intake and exhaust noise reduction of general high-pressure fans.

3: Application scope of fan muffler:

Fan is a universal mechanical equipment with a wide range of applications. Production in various industries such as power, mining, machinery, metallurgy, and chemical industry cannot do without fan. The noise generated by fans during operation often becomes a source of harm to workers' health and environmental disturbance. Especially for fans located near residential areas, the aerodynamic noise radiated from their inlet and outlet is a major factor in environmental pollution, forming a public hazard. It has become one of the main targets of noise pollution control in China's industrial sector in recent years.

Industrial fans are equipment that operates continuously. The International Organization for Standardization (ISO) sets a noise standard of ≤ 90 decibels for such equipment, and China's new standard is the same. This is also the basis for industrial enterprises to achieve continuous noise standards. However, without using noise reduction measures, the noise emitted by the fan inlet and outlet to the environment can reach 110-120 decibels, greatly exceeding the standard requirements.

threeStructural principle of ventilation and fan muffler:

Based on the spectral characteristics obtained from actual testing of noise sources in various industrial fan operation sites, the main basis for designing sound absorbers and fluid channels is to determine the required amount of noise reduction in which spectral ranges. At the same time, narrow rectangular channels with large sound-absorbing material finishes are used to enhance the absorption effect. In addition, when the noise source of the fan is at a high noise level, its spectral value is often more than one, and the requirements for its noise reduction are also different for different spectral bands.

For this purpose, the muffler of the ventilation duct and the muffler of the drum induced draft fan are both impedance acoustic flow type. A resistive structure is used to absorb and reduce high and medium frequency noise, and an anti type structure is used to reduce and eliminate medium and low frequency noise. At the same time, two types of absorption and noise reduction zones, high frequency and low frequency, are used in the resistive channel to maximize the width of the noise reduction frequency band and achieve good noise reduction effect.

Ventilation duct silencers and drum induced draft fan silencers are suitable for various centrifugal, axial, Roots blowers, and air compressors.

After the user installs this product as required, its noise level limit will not exceed85-90 decibels.If there is sufficient installation space for the section and length of the fan muffler, the section size can be changed and expanded to the width when the height is not enough. Our company can supply according to the design requirements. Increasing the length of the fan muffler can improve the noise reduction, but the corresponding resistance loss also increases.The muffler introduced in this instruction is suitable for various centrifugal and axial flow fans. In addition, our factory also designs and produces mufflers for gas turbines, Roots blowers, air compressors, and diesel engine exhausts for various purposes. Users are welcome to inquire and purchase.

Model and parameters of fan muffler

The standard specifies the emission limits and measurement methods for environmental noise at the boundary of industrial enterprises and fixed equipment factories(See Table 1)     Unit db (A)

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Safety Production Standardization Certificate Number:AQBJXXW202100026

quality management system (GB/T19001-2016 idt ISO9001:2015)Certification certificate:25021Q10338R0S

High tech Enterprise Certificate Number:GR202332017985

Da Shi "noise reduction equipment, payment will be made after installation is qualified!

Welcome to inquire by phone

mobile phone17511412888(Manager Li)

mobile phone17312347708

Email：dashijixie@126.com

Address: Keyuan Village, Dunshang Town, Ganyu District, Lianyungang City (within the factory area of the muffler manufacturer)