Noise damper, in particular for an air conditioning system of a railway vehicle

Abstract

The noise damper includes a casing delimiting an air passage, the casing having walls each includes an acoustic insulation layer. The noise damper includes: at least one baffle arranged in the air passage to separate the air passage in several channels, each channel extending substantially parallel to a longitudinal direction, and a helical deflector arranged in each channel, extending parallel to the longitudinal direction.

What is claimed is: 
     
         1 . A noise damper, comprising a casing delimiting an air passage, the casing having walls each comprising an acoustic insulation layer, wherein the noise damper comprises:
 at least one baffle arranged in the air passage to separate the air passage in several channels, each channel extending substantially parallel to a longitudinal direction; and   a helical deflector arranged in each channel, extending parallel to the longitudinal direction.   
     
     
         2 . The noise damper according to  claim 1 , wherein the casing is made of metal. 
     
     
         3 . The noise damper according to  claim 1 , wherein the casing is made of aluminum. 
     
     
         4 . The noise damper according to  claim 1 , having a length, in the longitudinal direction, substantially equal to 1 meter. 
     
     
         5 . The noise damper according to  claim 1 , wherein said at least one baffle is inclined in regard to the longitudinal direction, so that the channels have not a constant cross section along the longitudinal direction. 
     
     
         6 . The noise damper according to  claim 1 , wherein each baffle comprises an acoustic insulation layer on its faces. 
     
     
         7 . The noise damper according to  claim 1 , wherein each helical deflector has a helical surface extending around a central axis and extending radially from the central axis to an inner surface delimiting a corresponding channel. 
     
     
         8 . An air conditioning system, comprising the noise damper according to  claim 1 . 
     
     
         9 . A railway vehicle, comprising the air conditioning system according to  claim 8 . 
     
     
         10 . The railway vehicle according to  claim 9 , wherein the railway vehicle is an underground train.