Catalytic converter for automotive exhaust system
AssigneeMinnesota Mining and Manufacturing Company
InventorsRichard P. Merry, Philip D. Coates, Jr.
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Abstract
Catalytic converters for automotive exhaust systems wherein thin, resilient, flexible, intumescent sheet materials are utilized as mounting mats for catalytic monoliths are disclosed. Multiple wraps of such sheet materials have been found particularly useful and cost effective for positioning and supporting ceramic catalytic monoliths which have a large cross-sectional dimensional tolerance within the metallic casing of the converter.
Claims8
A method of producing a catalytic converter by mounting a ceramic monolith within a metallic catalytic converter casing comprising the steps:
- a. providing a metallic converter casing;
- b. providing a ceramic monolith having dimensions smaller than the interior dimensions of said metallic converter casing;
- c. determining the volume of the gap between the ceramic monolith and the metallic converter casing;
- d. layerwise wrapping at least two layers of a thin, resilient, flexible, intumescent sheet material about the periphery of said ceramic monolith, said intumescent sheet having a thickness less than 2 mm and greater than 0.5 mm and comprising from about 20% to 65% by weight of unexpanded vermiculite flakes, from about 10% to 50% by weight of inorganic fibrous material, from about 3% to 20% by weight of binder and up to about 40% by weight of inorganic filler material to yield a mount density of at least 0.64 g/cm.sup.3 ;
- e. placing said layerwise wrapped ceramic monolith into said metallic converter casing;
- and
- f. closing and sealing said metallic converter casing.
In a catalytic converter having a metallic casing, a unitary, solid ceramic catalytic element disposed within said casing, and resilient means disposed between said catalytic element and said metallic casing for positioning said catalytic element and for absorbing mechanical and thermal shock, the improvement comprising:
- said resilient means comprising at least two layers of a thin, resilient, flexible, intumescent sheet layerwise wrapped about the perimeter of the lateral surface of the solid ceramic catalytic element.
Dependencies are inferred from the claim text.