Abstract: An apparatus and a proces for the manufacture, by the extrusion method, of roof covering plates having at their underside a transverse flange shaped thereto. At a filling station cavities in the pallets corresponding to the transverse flange, are first filled with a hardenable plastic material such as fresh concrete, and said material is then compacted at at least one compacting station. Thereafter, a continuous layer of the material is deposited at a depositing station. The material is finally processed to roof covering plates.

Abstract: An apparatus for manufacturing concrete roof tiles by extrusion includes a coating system adapted to be supplied with green concrete and to apply a continuous layer of green concrete onto a continuous strand of movable, positively advanced bottom molds (14), a compacting roll (25) and a smoothing member (35) immediately downstream thereof in the manufacturing direction for compacting and possibly shaping the basic green concrete layer passing therebeneath on the bottom molds. There is provided downstream--as viewed in the manufacturing direction--of the smoothing member (35) for the basic layer (17) and separated therefrom by a gap (40) extending transversely to the manufacturing direction, at least a further smoothing member (45) for another layer, especially a cover layer (18), to be applied onto the basic layer (17). The material for said other layer is supplied under pressure through the gap (40).

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.