What is reactive silencer?

What is reactive silencer?

Reactive silencers are used to attenuate low frequency octave band noise – up to attenuation of 60 dB (A)- produced by the exhaust of rotating machines such as diesel / gas engines, compressors, pumps … Reactive silencers reduce noise pollution from exhausts. They are found on a wide variety of industrial sites.

What is sound attenuation in HVAC?

A sound attenuator, or duct silencer, sound trap, or muffler, is a noise control acoustical treatment of Heating Ventilating and Air-Conditioning (HVAC) ductwork designed to reduce transmission of noise through the ductwork, either from equipment into occupied spaces in a building, or between occupied spaces.

How does a silencer reduce noise?

Both types of silencers reduce noise by allowing the rapidly expanding gases from the firing of the cartridge to be decelerated and cooled through a series of hollow chambers. The trapped gas exits the suppressor over a longer period of time and at a greatly reduced speed, producing less noise signature.

How many types of silencers are there?

Silencers come in many shapes and sizes and most all of them can be classified into four types: reactive, dissipative, absorptive, and dispersive or diffusive.

What is an absorption silencer?

The absorptive silencer is the most common design. It determines that noise energy is “absorbed” by many different types of fibrous packing materials. As sound waves pass through the fibers of the absorptive material, the sound energy shrinks into small amounts of heat.

What is audio attenuation?

Basically, attenuation is a damping of sound, an interruption that diminishes the volume and quality of the sound wave. It’s because sound waves interact with different objects in different ways, and sound quality is reduced more by some objects than others.

How do duct silencers work?

These are specially designed for the purpose of stifling and insulating sound which is created by air duct equipment such as fans and AHUs. They act as a sound dampener, reducing vibrations and sounds through the production of expansion joints and compensators which absorb sound.

What is the difference between silencer and suppressor?

Some say a silencer is for reducing the sound, while a suppressor is more for eliminating muzzle flash. A suppressor does reduce some of the sound though. The simple answer is both words can be used interchangeably – meaning the terms Silencer and Suppressor refer to the exact same thing.

What is attenuation audio?

How do you select sound attenuator?

The following information is needed to determine silencer Insertion Loss (IL) and Pressure Drop (PD) performance:

1. Silencer IL requirements.
2. Unit size.
3. Forward (supply) or reverse (return) airflow direction.
4. Maximum allowable silencer PD.
5. Face velocity.
6. Length, width and height restrictions.

What is the difference between absorptive and reactive silencers?

Unlike reactive silencers, absorptive silencers primarily attenuate sound by absorbing sound energy, rather than reflecting it. These silencers use fibrous and porous packing materials to absorb sound waves and dampen the sound volume.

What is the self noise of a silencer?

The Self Noise – SN – is the noise power level in decibels generated by the silencer when inserted in the air flow. The Self Noise depends on the direction of the flow – if its forward or reverse. Absorptive or dissipative silencers use sound absorbing materials to attenuate sound waves.

Can the broadband sound attenuation characteristics of expansion chamber silencers be altered?

The broadband sound attenuation characteristics of expansion chamber silencers can be altered by their internal configuration. Three-dimensional modeling of such systems, especially in the presence of complex internal partitions, remains a challenging task.

What type of silencers are used in HVAC systems?

Reactive silencers are rarely used in HVAC systems. Diffuser type silencers have perforated pepper pots to slow down flow velocity and prevent the generation of low frequency noise and are mainly used for applications involving nozzles, control valves, jet engines etc.