Silencer elbow lined stainless steel elbow is a sound-absorbing material, a significant attenuation of sound waves. Sound attenuation consists of three parts: the absorption and reflection of the paraxial wave on the elbow wall, and the energy of the paraxial wave into the energy of the oblique wave when turning, effectively absorbed by the sound absorbing material. In the rectangular cross-section tube insert a right angle muffler elbow, and in the elbow on both sides of the shop plus sound absorption liner length of 2 to 4lz (lz is the characteristic width of the pipe cross section), then the insertion loss of high frequency than the same The length of the liner straight insertion loss to 10dB higher. The so-called high frequency, that is, higher than the frequency of the pipeline cut-off frequency. Muffler elbow at low frequencies, with the same length of liner straight pipe, no additional insertion loss.