Diesel particulate trap of perforated tubes wrapped with cross-wound inorganic yarn to form four-sided filter traps

Claim 1

A diesel particulate filter comprising (a) a casing having at least two ends; (b) means for connecting said at least two ends of said casing to an exhaust system; (c) means for supporting at least one tube; (d) at least one substantially rigid tube extending between said at least two ends of said casing, said at least one tube having two ends, an outer surface, and perforations that provide a perforated area, said at least one tube being supported by said supporting means; (e) a filtering element comprising inorganic yarn, said inorganic yarn being substantially helically cross-wound around said at least one tube to cover said perforations, wherein said inorganic yarn comprises a core from which at least one of loops of continuous fibers or fiber segments extend outwardly, wherein successive convolutions are oppositely wound in each layer to provide interwoven cores, cores of successive convolutions of each successive layer are radially aligned to provide walls that are spaced to define four-sided openings, said walls providing stabilization to said filtering element against exhaust forces, wherein said convolutions of said yarn at said perforated area of said at least one tube extend at an angle in the range from about 30° to about 70° to the axis of said tube in each winding direction, and wherein said at least one of loops of fibers or fiber segments project into each of said four-sided openings, with at least one of loops of fibers or fiber segments of adjacent convolutions being intermeshed to provide with each of said four-sided openings a trap for diesel exhaust particulates.