What is the principle of silencer?

Here are two different kinds of muffler principles:

1) Absorption type: Let compressed air pass through porous sound-absorbing materials, and heat is generated by air flow friction, so that the pressure energy of the gas can be partly converted into heat energy, thereby reducing exhaust noise. Absorption muffler has good performance in eliminating medium and high frequency noise. Generally, the noise can be reduced by more than 25bB. Sound absorbing materials mostly use polyvinyl chloride fibers, glass fibers, sintered copper beads and so on.

2) Expansion interference type: The diameter of the muffler is larger than that of the exhaust hole. The airflow diffuses, collides and reflects inside, interferes with each other, reduces the noise intensity, and finally discharges into the atmosphere from the porous shell with larger aperture. It is mainly used to eliminate medium and low frequency noise.

The method of centralized exhaust is to lead some gas discharged from valves to the main exhaust pipe with large inner diameter. The exhaust cleaner can be installed at the outlet of the main exhaust pipe, and the outlet of the exhaust pipe can also be set outside or in a ditch to reduce the noise in the working environment. This method uses the principle of expansion interference to reduce the noise.