Abstract: A diesel engine secondary oil filter is formed from a punched tinned steel spiral lock seam center tube, with a flanged cap at one end and a flanged threaded outlet at the other end. A layer of polyester non-woven media is wrapped in one wind around the center tube. A yarn is wound is a 27-diamond pattern in a first yarn section out to two inches outer diameter. The yarn is tied off. Knitted socks are first placed partially on axial ends of the first wound section, leaving half of the socks extending over the ends. A sheet of activated carbon paper about 1/6 of an inch thick and about 52 inches long is rolled onto the filter cartridge with about nine turns. The carbon paper is made of a cellulose paper impregnated with about 50% activated carbon powder by weight.

Abstract: A method of filtering internal combustion and industrial engine oil includes providing a specially wound filter element in a canister and passing the liquid through it slowly (e.g., 1-2 quarts per minute). The filter element includes a length of cotton/cellulose paper composition yard wound on a core in an irregular winding pattern such that some layers filter smaller (e.g., 1 micron) particles and others further from the core filter larger (e.g., 5 micron) particles. A filter element constructed according to the invention includes a core having a hollow interior, a perforated outer surface in fluid communication with the hollow interior, an open first end in fluid communication with the hollow interior, and a closed second end. A length of yarn of cotton and cellulose paper composition is wound in a series of layers over the outer surface of the core in the irregular winding pattern such that some layers closer the core filter particles down to a smaller size than do other layers further from the core.