Improvements to exhaust silencers (mufflers) and to methods for manufacturing them

摘要

Between the outer longitudinal surface (6) of a porous and hollow cylindrical cartridge (2) and the internal longitudinal surface (7) of a sleeve (5) made of relatively rigid plastic, an annular expansion chamber (8) is left free, which chamber is closed, except for its communication with the inside of the cartridge (2) via the pores in the latter. <IMAGE>