Abstract: A filter element is formed by spirally winding at least two layers of filter material about a central, perforate supporting core. The layers include a relatively fine porous filter material and a relatively coarse porous filter material. The layers may be formed from blankets of material, or one or both layers may be pleated. The fine filter material extends beyond the edge of the coarse filter material to overlie and close the longitudinal ends of the layers of the coarse material. Fluid to be filtered passes radially through the element until it encounters a clogged or plugged area. The fluid will then take a circumferential spiral route until it again finds an open area of the filter and can pass radially toward the core.

Abstract: A spin-on filter coalescer unit having a flow reversing assembly. The filter-coalescer unit includes a cylindrical body which contains an annular filter element surrounded by a coalescing element, and a final separation stage is spaced radially outward of the coalescing element. A cover encloses the open end of the body and is provided with a central outlet port and a plurality of circumferentially spaced inlet ports. The flow reversing assembly comprises a pair of baffle members, one of which can be the cover, which are spaced apart to define a chamber that communicates with the outlet. A plurality of tubular connecting members form sealed conduits extending through the baffle member and establish communication between the inlet ports and the central axial passage within the filter element.

Abstract: A graduated density liquid filter element for use in an internal combustion engine. Two layers of fibrous media of dissimilar size and having different permeability are disposed in partially overlapping relation and wound in coiled form to provide a generally cylindrical filter element in which resistance to the flow of the liquid varies along the length of the element.