Drying cylinder of the type for plants for the production of bituminous macadams

A rotary drying cylinder (1) for plants for the production of bituminous macadams, the cylinder extending, between a first end (3) and a second end (4) opposite the first, along a main axis (2) which is set at an angle to the ground, and having an inner surface (13);

• the drying cylinder (1) comprises a burner (7), connected to the cylinder at the second end (4), and generating a flame (9) which extends inside the cylinder towards the first end (3) and a plurality of container blades (31) mounted on the inner surface (13) of the cylinder;
• the cylinder being characterised in that it internally comprises a tube-shaped shielding structure (10), connected to the drying cylinder (1), having an axis of extension parallel with the main axis (2) and extending from the burner (7) towards the first end (3) for a predetermined length so that, in practice, the flame (9) is at least mainly confined within the shielding structure (10) in a flame zone, the cylinder also being characterised in that it comprises a separating ring (12) between the shielding structure (10) and the inner surface (13) of the drying cylinder (1) so that a material being dried can pass in the separating ring (12), the cylinder also being characterised in that the container blades (31) are inside the separating ring (12) and are mounted on the inner surface (13) of the cylinder at least at the separating ring (12);
• the shielding structure (10) comprising a plurality of hollows (17) facing towards the inner surface (13) of the drying cylinder (1) for containing, in practice, the material being dried, the shielding structure (10) being at least mainly made of heat-conducting materials and confining the material being dried in the separating ring so shielding the flame (9) from the material being dried which is in transit in the separating ring (12) and preventing the material from making contact with the flame (9), the shielding structure (10) being configured such that the material does not pass through the shielding structure (10) into the flame zone during rotation of the cylinder, characterised in that between the first end (3) and the separating ring (12) and close to the latter there is a blade assembly (36) comprising a set of insertion blades (37) connected to the inner surface (13) of the drying cylinder (1) for inserting the materials being dried in the separating ring (12);
• each of the insertion blades (37) forming an inner containment chamber (38), and characterized in that the containment chamber (38) of each insertion blade (37) is closed at the side (39) facing towards the first end (3) and open at the side facing towards the second end (4), thus in practice facilitating insertion of the materials being dried into the separating ring (12).