Patent ID: 8236250

Claim:
An exhaust gas after-treatment device, comprising a metal shell ( 1 ) defining a cavity with an intake pipe ( 2 ) and an outlet pipe ( 3 ) and two foam segments ( 4 a ; 4 b ) made of layered metal foam sheets set in the path of communication between said intake pipe ( 2 ) and outlet pipe ( 3 ), wherein said foam segments ( 4 a ) and ( 4 b ) are separated by a perforated diaphragm ( 5 ) wherein the diaphragm has a plurality of perforations and wherein the perforations thereof ( 5 ) may be locally variable, each foam segment comprising a plurality of layers of metal foam sheets, which are set about the longitudinal axis ( 6 ) of the shell ( 1 ) in such a way as to define, inside the shell ( 1 ), an inlet chamber ( 7 ), an outer chamber ( 8 ), and an exit chamber ( 9 ), the said chambers communicating with said intake pipe ( 2 ) and said outlet pipe ( 3 ) in such a way that during use, the flow of the engine exhaust gases is forced from the inlet chamber ( 7 ) to the outer chamber ( 8 ) and from the outer chamber ( 8 ) to the exit chamber ( 9 ), thus assuming radial components of velocity with respect to the longitudinal axis ( 6 ) of the shell ( 1 ).