Catalytic converter having a pair of catalyst pellet beds with a plenum

Abstract

In a catalytic converter, a sheet metal housing has a pair of shell members enclosing a pair of sheet metal catalyst pellet beds each having an inner bed member and an outer bed member with the inner bed members also forming a plenum between the beds. At least one of the inner bed members has the area containing its perforations displaced away from that of the other inner bed member to form the plenum therebetween. A tube receiving cavity is further formed between the inner bed members that is open on opposite sides to the plenum. An air tube extends through an opening between the flanges on the outer bed member and an opening between mating peripheral flanges on the inner bed members and the housing shell members and is received in the tube receiving cavity between the inner bed members. The air tube has a closed end in the plenum and has holes spaced along the length thereof which open to the plenum to deliver air thereto. A weld external of the housing is provided between the air tube and the flanges on the outer bed members and housing shell members whereby the air tube is sealingly fixed to the outer bed members and the housing shell members but is free to expand therein and relative to the inner bed members while also maintaining the predetermined spacing in the plenum therebetween.