The round channel sounder is one of the other flagship products of Shahrokhi Technical Institute. These silencers are designed and selected according to the existing sound level, the amount of sound absorption inside the channels and branches, the amount of sound absorbed in the environment and other factors of reducing the sound level. It is obvious that when the initial sound level produced by the fan of the ventilation device is not available, the experts of this institute obtain this level accurately using sound level analysis devices and design the noise reduction device based on it.
Features of channel sounder of Shahrokhi Technical Institute

1- Moving the air flow directly to increase the flow rate and reduce the pressure drop.
2- round and hard tip to maximize noise reduction.
3- Round inlet to reduce disturbance, pressure drop and sound produced by the silencer.
4- Without any protrusions to eliminate disturbances and noises produced in the sounder.
5- Having hard surfaces in the place of air passage and minimizing the accumulation of pollution.
6- Corrosion protection of sound absorbent materials by mesh sheets.

Application of round channel sounder

In the air conditioning ducts, generally due to the operation of the fan, whether axial fans or centrifugal fans, an unpleasant sound is scattered in the ventilated environment, and the intensity of this sound depends on various factors such as the type of fan, the distance of the fan from the place, the material and The type of canals and branches, the material of the surrounding walls and other such factors are different, but in any case, the presence of these sounds will create an uncomfortable environment for the residents.
Today, channel silencers are used to solve this problem. These silencers with a special design, in addition to the least impact on the ventilation air flow, eliminate the noise produced by the air conditioners to a very high extent.
The type and design of these silencers are such that they absorb sounds produced with all kinds of frequencies and in the range of human hearing (from 63 to 8000 Hz) they provide comfortable environmental conditions in terms of sound. In this regard, the design of a sound absorber that can provide these conditions in the environment is of particular importance, so that in case of improper design, the sound absorber will not only not be able to absorb the sound, but as the cause of the sound, it will cause problems. It will make a lot.
The operation of channel loudspeakers

The basis of sound absorption in sound absorbers is based on the absorption of waves in porous materials. In such a way that the round channel silencer has parallel rows of sound absorbing materials that the moving waves along the channel are absorbed after hitting these sound absorbing walls. To increase the efficiency of this absorption, perforated metal sheets are used, which have a very high sound absorption coefficient. These perforated sheets, while directing the waves to the absorbing material, consume the waves to a large extent.

The arrangement of perforated sheets and sound absorbent materials and air passage layers in a sequence creates specific paths of air passing through the absorbent materials, which achieves the least amount of disruption of the flow pattern and the highest amount of trapping of sound scattering waves. make
Normally, for each air conditioning system, the sound production characteristics are extracted and announced, and according to the type of system, sound intensity, and air flow rate, a suitable silencer with a specific number of blades is designed and introduced.

Sound absorbing materials are of special importance as the main part of sound absorption in a sound absorber, while these materials should have special characteristics and special protective conditions due to health and environmental issues. In many cases, high resistance to heat, non-emission of toxic gases during fire, resistance to fungus and bacteria, and no dust formation in the ventilation system are considered to be the most important requirements of sound absorbing materials. In addition, in environments with special conditions, these restrictions may change to a large extent or be applied more strictly. What is common today in sound absorbers as sound absorbing insulations is the use of stone wool, glass wool insulations and polymer series insulations such as EPDM, each of these insulations has its own advantages and disadvantages and for some cases Special has a special use.

In the silencers made by this institution, the types of insulation mentioned above are used according to the specific sensitivities of the project or the special request of the customer or the internal design of the company, but usually this company uses compressed rock wool insulation for its silencers. It uses heat that can withstand up to 800 degrees due to its alkaline environment and is not a suitable substrate for the growth of fungi and bacteria, so it is at an acceptable level in terms of health.

The only point that should be considered in the use of this type of insulation is the use of dense coatings in the final layer of these insulations to prevent the release of insulation particles in the environment.
How the silencer works

Acoustic silencers, also known as dissipative silencers, use sound-absorbing materials to weaken the sound level. When the sound inside the air channel passes past the silencer, sound energy or acoustic energy enters the silencer feathers through the holes in the iron sheets of the silencer body. These perforated plates prevent the erosion of sound-absorbing materials at high speeds, and at the same time, due to the holes in the surface, they allow the passage of a large amount of sound energy, which is why they can be considered acoustically invisible. .

Inside the silencer blade, the sound energy collides with the sound absorbing materials, these materials are made of glass fibers as a standard. The friction between the sound energy and the glass fibers converts the sound energy into heat and causes the sound energy to decrease and thus the level of