Abstract: The process for the visible marking of carrierless polymeric membranes for filtration purposes and for the reverse osmosis is characterized in that the marking symbols are first of all printed onto the casting support, onto which subsequently the casting mass is poured which serves for the production of the membrane. During the removing of the pre-solidified, solidified or finished membrane from the casting support, the printing dye which has an outline corresponding to the marking symbols, is taken up by the membrane and is taken along by the latter from the casting support. Preferably, the printing dye which had been imprinted onto the casting support when the membrane casting mass is poured on, has at least dried in a wipe-proof manner and, in this state, is soluble in the solvent-system of the membrane casting mass.

Abstract: A backpressure grid plate is provided for a pressure filtration system of the type comprising a housing with an inlet and outlet for conducting fluid to be treated, a filter disposed in the housing between said inlet and outlet, and a backpressure grid means arranged between the filter and the inlet. The backpressure grid means comprises a plate containing minute openings which are equal in size and distributed unevenly over the surface area of the plate in such manner that the surface distribution density of the openings is lowest within an inner impact area of the plate which receives inflowing fluid to be filtered and is highest within a proximity area of the plate located immediately adjacent to and surrounding the impact area. The surface distribution density of the openings within an outer area surrounding the proximity area is lower than that of the proximity area and higher than that of the impact area.

Abstract: A housing for single-use pressure filtration units comprises upper and lower parts. A filter element is to be clamped between the housing parts. The upper housing part, preferably molded in one piece of synthetic material, includes a plurality of radial ribs which hold the filter element down, and a baffle disk supported solely by the ribs. The disk is spaced beneath the axial inlet duct to prevent direct impingement of axially incoming pressurized fluid against the filter element. Only some of the ribs support the disk, the remaining ribs terminating short of the disk to promote uniform radial distribution of fluid deflected by the disk. Radially inner ends of the disk support ribs are inclined downwardly and inwardly and act in funnel-like fashion on the inflowing fluid.