Exhaust gas treatment device with insulated housing construction

摘要

An exhaust gas treatment device for internal combustion engines and the like includes inlet and outlet end caps (2,3), first and second catalyst substrates (4,5), and a two-piece housing. A first, cylindrically-shaped housing member (7) has a hollow interior in which the first substrate (4) is retained, a first end sealingly connected with the inlet end cap (2), and an opposite second end with a radially reduced section (11). A second cylindrically-shaped housing member (13) has a hollow interior in which the second substrate (5) is retained, a first end sealingly connected with the outlet end cap (3), and an opposite second end with a radially enlarged section (17) sized to receive therein the second end (11) of the first housing member, whereby the reduced section (11) of the first housing member (7) and the enlarge section (17) of the second housing member (13) are spaced radially apart a predetermined distance to define an annularly-shaped space or gap (19) which thermally insulates the associated portion of the exhaust gas treatment device.