COMBINED NOISE SUPPRESSOR Russian patent published in 2017 - IPC F01N1/04 

FIELD: machine engineering.

SUBSTANCE: suppressor consists of a cylinder body, rigidly connected to the end inlet and outlet branch pipes, a sound absorber, located between cylinder body and perforated element and an acoustic transparent material, installed between the perforated element and the sound absorber. The sound-absorbing cylindrical insert is mounted along the suppressor axis; a conical fairing is fixed at one of the perforated cylindrical insert end faces, and the cylindrical insert is fixed to the inlet and outlet branch pipes by at least two stiffeners, located in the plane perpendicular to the suppressor axis. Inside the cylindrical insert there is a sound absorber and the acoustically transparent material, located between the perforated element of the insert and the sound absorber. The sound absorber is made in the form of sound-absorbing element of annular type, which walls are made in the form of the rigid and the perforated walls, between which there are two layers: the sound-reflecting layer adjacent to the rigid wall and the sound-absorbing layer adjacent to the perforated wall. The layer of sound reflecting material is made from the complex profile composed of evenly distributed hollow tetrahedrons allowing to reflect acoustic waves falling in all directions.

EFFECT: noise suppression efficiency improvement.

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