What are the types of generator silencers? How many noise levels does it have?  

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In the field of generators, silencers have the same effect on internal combustion engines as they have on engines in automotive and building applications. Both are designed to reduce the noise and exhaust emissions generated during fuel combustion.

 

There are three basic designs for silencers:

1. The Reactive Silencer， its internal structure consists of three chambers connected by pipes, the exhaust noise bounces between the chambers, which reduces the output noise and is used to reduce medium and low-frequency noise.

2. Absorptive Silencer - the internal structure is made of glass fiber or insulating glass. When the exhaust gas flows through the insulation, its noise is reduced. This method is used to reduce high-frequency sound waves.

3. Combination Silencer, is a structure combining a reaction silencer and absorption silencer. The absorption material is installed in the chamber design of the reaction silencer, which allows reducing all frequency designs.

 

Cylindrical Silencer

The cylindrical silencer is one of the earliest developed shapes. They can be built into all three basic designs and can be used for internal and external applications. Silencers can be installed horizontally or vertically to meet the requirements of any application. It is considered one of the most economical silencers.

 

Thin silencer

These silencers can be produced in various shapes, such as rectangles, ellipses, and circles. The selected shape is determined by the available space. They are usually used for generators in sound attenuation enclosures.

When the generator operates in a flammable environment, the exhaust system must be changed to ensure that sparks generated during combustion will not be discharged into the external atmosphere. Spark brake silencers are usually cylindrical and are of improved reactor design. This allows carbon sparks to circulate through the silencer and fall into the collection tank. The collection tank must be cleaned as part of the maintenance procedure.

Sometimes the exhaust gas temperature can be as high as 1400 degrees Fahrenheit. These gases are often released into the atmosphere. The heat recovery silencer is used to utilize the heat in the exhaust gas before it enters the atmosphere.

 

Emission control silencer

Because combustion gases consist of many gases, some of which are extremely harmful to the human body. The Environmental Protection Agency (EPA) enforces exhaust regulations to reduce harmful exhaust emissions. The environmental protection department strictly controls the emission of generators that provide the main power for the facilities. Current relevant regulations require the use of catalytic converters. The basic converter consists of a honeycomb grille design and is placed directly in the exhaust system behind the exhaust manifold. This position allows the exhaust gas to be at the maximum temperature required for normal operation. Many new silencers combine converter designs with silencers.

Relevant regulations also cover the content of particulate matter in the exhaust gas. The particulate filter can be used to reduce the soot content in the exhaust gas. The inside of the filter is made of ceramic material. The exhaust gas passes through the material and the soot is collected. Lean burn engines can also use additives to further reduce harmful emissions.

 

Rated sound of generator silencer

The sound intensity emitted by the exhaust system is measured in decibels. A decibel is a unit of measurement used to express the ratio of one physical attribute to another on a logarithmic scale. Decibel (DBA) is a measurement used to approximate the response of the human ear to sound.

In the early days of silencer rating, there were four basic grades. Industrial, commercial, residential and hospital grades are considered to be the industry standards for the manufacture of silencers. During this period, the amount of sound reduction varies from manufacturer to manufacturer. The Generation Systems Association (EGSA) has developed a rating guide to provide a consistent silencer rating for any manufacturer belonging to the association. This has become the industry standard in the manufacturing industry.

 

Common grades of generator silencers are:

Industrial Grade - 15 to 20 dB reduction in exhaust noise

Residential Grade - 20 to 25 dB reduction in exhaust noise

Critical Rating - 25 to 32 dB reduction in exhaust noise

Supercritical rating - 30 to 38 decibels less exhaust noise

Hospital Grade - 35 to 42 dB reduction in exhaust noise

Hospital Plus - 35 to 50 dB reduction in exhaust noise

Extreme - 40 to 55 dB reduction in exhaust noise

Ultra-Extreme - 45 to 60 dB less exhaust noise

It should be noted that not every silencer and style is applicable to all classes. Each manufacturer produces various models of different grades. The production cost and the physical performance of the silencer determine the grade availability.