Abstract: A filter consisting of a housing, a rigid, porous filtering element, means for forming a primary filter path along the filtering element, and a non-rigid expanding element, wherein when a solution to be filtered flows through the primary flow path, filtrate passes through the rigid filtering element and particulate matter is retained on or in the filtering element. When the filter surface becomes clogged, the incoming solution is bypassed, reduced, or discontinued and the non-rigid expanding element expanded to first form discrete compartments of filtrate between the expanding element and the filtering element and secondly to force the discrete volumes of filtrate back through the filtering element into the flow path for removal. In one embodiment, the housing and filtering element consist of hollow cylinders and the expanding element extends lengthwise through the interior of the filtering element, expanding outwardly to expel particulate matter.

Abstract: A flow-through filter including a two-stage valve head assembly and a filtering body which is designed to provide a helical flow path for the solution over a cylindrical porous filter which captures the particulate matter contained by the solution being filtered. An extended filtering capacity is achieved due to the ability of the filter to remove and eject separated solids retained by the porous filter. An expander tube is positioned within the filter and, when connected to a pressure source, the expander tube forces solids from the pores and into the primary volume of the filter where a flushing medium is circulated. The filter clearing is made possible by an accurately controlled and metered volume of uniformly distributed reverse flow which effectively lifts the solid material out of the pores.