Pellet type catalytic converter

In a catalytic converter for catalytically treating the exhaust gases emitted from an internal combustion engine, including a container, exhaust gas inlet means at one end of said container, exhaust gas outlet means at the other end of said container, a catalyst pellet casing supported within said container, said casing being packed with a plurality of catalyst pellets and formed into a parallelpiped shape consisting of a first pair of parallel spaced wall sections respectively facing the inlet and outlet means, a second pair of parallel spaced wall sections sealingly covered with side wall portions of said container, and a third pair of parallel spaced wall sections exposed to the main portion of the interior of said container, one of said third pair of parallel spaced wall sections being exposed to the exhaust gases coming from said inlet means and the other one of said third pair of parallel spaced wall sections being exposed to the exhaust gases admitting into said outlet means, and a plurality of louvers defining respective openings formed in said pellet casing for providing a fluid communication between the interior and the exterior of said casing thereby allowing the exhaust gases from the inlet means to pass through the interior of said casing before reaching said outlet means, the improvement comprising:

• all of said louvers being formed in said third pair of parallel spaced wall sections, and each of said louvers comprising an elongated strip portion having its longitudinal ends integrally attached to its respective one of said third pair of parallel spaced wall sections and a central unsupported portion projected toward the inside of said casing while crossing directly over the corresponding louver opening, whereby when said casing is heated, the third pair of parallel spaced louvered wall sections will tend to curve due to expansion forces toward the inside of said casing.