Abstract This invention presents a filter and a method of filtration which is specifically adapted for the filtration of solid fibrous contaminants from a liquid, the contaminants having a low breadth-to-length ratio. The filtration of such fibers has long posed a problem due to the tendency of such fibers to surface load existing filter media. One aspect of the invention resides in the utilization of a relatively large granular media, i.e., an organic polymeric granular media in which the granules are essentially spherical and of an average size ranging from about 0.050 inch to 0.375 inch. It has been found that the interstices of such relatively large media granules will effectively remove fibrous materials while, at the same time, the granules are so large as to resist appreciable surface loading. Another aspect of the invention resides in the ''''backwash'''' procedures for removing accreted fiber contaminants from the granular filter bed. This procedure involves forming the organic polymeric granules into a slurry in the liquid being filtered, while violently agitating the slurry to wash entwined and matted fibers contaminants from the individual granules and separating the fibrous contaminants from the slurry together with a portion of the liquid being filtered.
flowing a mixture of said fibrous solid contaminants and liquid from said inlet opening through said media to said outlet opening, thereby accreting said fibrous contaminants in said body of media;
Claim 2
Dependent Claim
173 words
periodically cleansing said body of media of accreted fibrous solid contaminants by the steps of: a. terminating the flow of said slurry through said inlet opening, b. agitating the filter media by creating a backwash flow therethrough in a direction opposite to the filtering flow of step (2) from a backwash inlet to a backwash outlet, said backwash flow creating sufficient turbulence to form a slurry of said filter media and to detach said contaminants from said filter media granules, c. flowing said slurry through a separator located within the backwash flow path exterior of said housing thereby separating at least a portion of said contaminants from said slurry, the separator having a separating wall constructed and arranged to permit the fibrous contaminants but not the filter media to pass therethrough, and d. reforming said body of filter media by causing said slurry to flow from said separator to said housing and through said housing between said inlet and outlet opening of step (1) prior to re-establishing the filtering flow of step (2).