Abstract: A low twist, high bulk filtration roving is prepared by wrapping a sliver comprised of individual fibers, around a core in the conventional manner. Exemplary of the bulk fibers which may be employed are naturally occurring fibers such as jute, cotton, animal hair; synthetic polymer fibers, such as acrylic, nylon, polyester, olefin, aramid, teflon; man-made organic fibers deriving from natural sources such as rayon or cellulose acetate; and inorganic fibers such as metal, glass, graphite; or a blend of two or more of these fibers. Examples of the core, which can be continuous filaments, monofilaments or spun yarn, are one or more strands of the same composition as the fibers, or a combination thereof, twisted paper which can be plain, impregnated or metallized, and metal wire. Where the material is capable of being cast in film form, slit film may be employed as the strand(s). The composite roving is wound upon a rigid perforated tubular center to form a filter cartridge.

Abstract: An interlocked yarn having a plurality of continuous filaments which have substantially no twist and having at spaced intervals along the length thereof at least one of the filaments encircling the other filaments to interlock the filaments together. The method of making the interlocked yarn includes feeding a plurality of continuous filaments into a fluid jet which has a fluid medium passing therethrough in a direction substantially counter to the direction of travel of the filaments. The interlocked filaments are pulled away from the fluid jet at a rate less than the feed rate. This produces an interlocked yarn having some of the filaments encircling the other filaments to provide an interlock at spaced intervals which eliminates the need to twist the bundle of filaments.