Apparatus for screening

An apparatus for removing solid and/or semi-solid bodies (41) from a liquid, where the apparatus includes a helix (3) formed by a threaded blade (33) and rotary about its geometric axis (32) and disposed in a path (7) which makes an angle (α) with a horizontal plane, and where the apparatus includes drive means (30) for rotating the helix about its axis, characterized in that the apparatus includes a first container (1) comprising said path (7) and a second container (2) which, in the lower region (35) of the apparatus surrounds the first container (1) under the formation of a cavity substantially discrete in relation to the surroundings, that the cavity includes a first space (26) disposed between the wall (17) of the first container and the wall (27) of the second container;

• that the first container (1) is provided with an inlet (13) for the supply of liquid containing the solid and/or semi-solid bodies (41);
• that the wall (17) of the first container (1) is provided with passages (15) through which liquid passes from the first container (1) to the space (26) between the first container (1) and the second container (2);
• that said passages (15) are dimensioned in order, on flow of the liquid through them, to separate solid and/or semi-solid bodies (41) transported by the liquid towards the inside of the wall (17) of the first container;
• that the helix (3) is disposed, on its rotation, to displace the separated solid and semi-solid bodies in the longitudinal direction of the path;
• that the space (26) between the walls (17, 27) of the first and second containers is connected to an outlet (24) for liquid;
• that a discharge aperture (14) for bodies separated from the liquid is disposed in the upper region (11) of the first container (1);
• that a mechanical abutment (50) is associated with the discharge aperture (14) for controlled opening and closing of the discharge aperture;
• that the conveyor helix (3) terminates a distance from the discharge aperture (14) for forming a helix-free zone (16) between the end (34) of the conveyor helix (3) and the upper end wall of the inner container;
• and that the helix-free zone includes a portion located between the end of the conveyor helix and the discharge aperture (14), in which portion the first container is provided with said passages (15) for the passage of liquid.