Acoustic attenuation device

Abstract

An acoustic attenuation device including an elongated hollow body having an open upstream end taking the form of a head for coupling to a compressed air outlet, and a closed downstream end, the hollow body having a sidewall with a plurality of air exhaust openings arranged in the downstream part, where the hollow body contains at least one upstream buffer lining forming a longitudinal filter and at least one downstream filtering lining forming a sheath.

1 . An acoustic attenuation device comprising an elongated hollow body having an open upstream end taking the form of a head for coupling to a compressed air outlet, and a closed downstream end, said hollow body having a sidewall with a plurality of air exhaust openings arranged in the downstream part, wherein the hollow body contains at least one upstream buffer lining forming a longitudinal filter and at least one downstream filtering lining forming a sheath. 
   
   
       2 . The device as claimed in  claim 1 , wherein the upstream lining is formed by rolling up on itself a filtering mesh formed of a suitable material. 
   
   
       3 . The device as claimed in  claim 1 , wherein the upstream lining takes the form of a compartment containing lining elements formed from a loosely packed suitable material. 
   
   
       4 . The device as claimed in  claim 1 , wherein the downstream lining is disposed around an open mandrel designed to hold it. 
   
   
       5 . The device as claimed in  claim 4 , wherein the downstream lining is formed by winding of at least one band of at least one suitable material (around the mandrel. 
   
   
       6 . The device as claimed in  claim 4 , wherein the downstream lining is composed of at least one sheath formed of a suitable filtering material surrounded by a retaining jacket under tension. 
   
   
       7 . The device as claimed in  claim 6 , wherein the filtering sheath and the retaining jacket under tension are formed from bands of the same width wound one over the other around the mandrel. 
   
   
       8 . The device as claimed in  claim 7 , wherein the band designed to form the retaining jacket under tension has a greater length than the filtering band. 
   
   
       9 . The device as claimed in  claim 6 , characterized in that the retaining jacket under tension is made of stainless steel cloth. 
   
   
       10 . The device as claimed in  claim 1 , wherein the downstream lining comprises at least one composite material. 
   
   
       11 . The device as claimed in  claim 10 , wherein the composite material is a non-woven fiber glass material. 
   
   
       12 . The device as claimed in  claim 1 , wherein a multi-perforated washer is disposed at an inlet of the upstream lining. 
   
   
       13 . The device as claimed in  claim 1 , wherein a centrally-perforated washer is disposed between the upstream lining and the downstream lining.