Filter unit for whole blood and blood derivatives

Filter unit for blood and blood derivatives comprising a body defined by two injection-moulded half-shells of thermoplastic polymer material, there being present between said half-shells a cavity containing a filtering element having two opposing flat faces, an inlet opening and an outlet opening made on the opposing outside surfaces of said body communicating with said cavity, wherein each of said half-shells comprises a projecting perimetral flange, the perimetral flanges of the overlapping half-shells in direct contact and welded together along a single weld line to define a flange of the body of the filter unit and join the two half-shells together, each perimetral flange projecting outwardly away from the cavity to define an inner surface, a first inner surface of a first half shell being mated to and directly engaged with a second inner surface of a second half shell, the filtering element being wholly contained within cavity of the body and pressed by shelves projecting into the cavity from each half-shell, at least in the vicinity of one of the perimetral edges and on the two opposing faces, said shelves holding said filtering element in a stable position within cavity, said thermoplastic polymer material being yielding and semi-rigid, the thermoplastic polymer material having a Shore A hardness of between 85 and 95.