Abstract: A pressure or vacuum filter leaf for use in separating solids from liquids includes a filter medium which is constructed of a pair of filtering screens each having a plurality of widely spaced support wires, and a plurality of closely spaced surface wires extending generally perpendicular to the support wires and connected thereto along one side of the support wires. The surface wires have a wedge shaped cross-section with the apex of the wedge connected to the support wires. The opposite flat surface of the wedge of each surface wire is disposed in a flat plane with the spacing between each surface wire forming narrow filtering slots extending along the plane. The filtering screens are connected together in opposed relationship with the surface wires of each screen in spaced relation to form an internal chamber. The flat surfaces thereof face away from each other and the support wires of each screen are disposed between the surface wires of the screens.

Abstract: An improved filtering septum for a restricted flow of liquid for filtration and liquid clarification having a pair of metal sheets each having an array of closely spaced small diameter perforations punched therethrough so as to form burrs on the inner face of each of the sheets at the periphery of the perforations, secured in face-to-face relation with the perforations of one sheet completely out of registry with those of the other such that the burrs of each sheet bear against unperforated areas of the other sheet along lines of imperfect contact pervious to a restricted flow of liquid.