Abstract: Filter press apparatus comprises a plurality of substantially parallel filter plates assembled as a unit and located within a substantially rigid outer shell to provide a closed vessel to which can be supplied medium under pressure to be filtered via the plates, a substantially impermeable primary membrane lining the shell for forming a substantially incompressible boundary wall to the unit on supply of pressure medium to the space between the primary membrane and the shell, and a secondary membrane having an intermediate extent between the primary membrane and the unit which, with the primary membrane urged towards the unit, moves axially with the unit and slides relative to the primary membrane to eliminate stress in the primary membrane during the compression stage.

Abstract: An endless belt filter for separating liquids and solids from a mixture comprises a liquid-permeable filter belt below the upper run of which is positioned at least one suction tray moveable in the direction of the upper run of the belt, at least one hollow, elongate vacuum rail below the suction trays extending the length of the upper run of the belt, the suction trays seating on the vacuum rail to be guided thereby in their longitudinal movement therealong, and a vacuum source connected to the hollow interior of the vacuum rail, the trays including one or more apertures communicating into the hollow interior of the vacuum rail whereby an under pressure is applied to the trays by the vacuum source to draw liquid from the trays into the vacuum rail. The trays are supported by a pneumatic cushion.