Abstract: A Screw for use in a twin-screw assembly of an elastomer mixture extruder with a threaded part with a single-start thread which defines at least three different sectors of the screw. The three sectors have an intake segment to capture the mixture fed from outside to push it downstream along the longitudinal direction, with a cross-section of the through-flow channel between adjacent flanks of the thread which is constant over at least two pitches or a rotation through 720 degrees of the thread. A transition sector which has a cross-section of the through-flow channel variable and smaller than the cross-section of the through-flow channel and is designed to cause an increase of the thrusting pressure acting on the mixture in transit in the longitudinal direction; and a high-pressure sector designed to cause the compression of the mixture to obtain a maximum pressure of the mixture.

Abstract: A Screw for use in a twin-screw assembly of an elastomer mixture extruder with a threaded part with a single-start thread which defines at least three different sectors of the screw. The three sectors have an intake segment to capture the mixture fed from outside to push it downstream along the longitudinal direction, with a cross-section of the through-flow channel between adjacent flanks of the thread which is constant over at least two pitches or a rotation through 720 degrees of the thread. A transition sector which has a cross-section of the through-flow channel variable and smaller than the cross-section of the through-flow channel and is designed to cause an increase of the thrusting pressure acting on the mixture in transit in the longitudinal direction; and a high-pressure sector designed to cause the compression of the mixture to obtain a maximum pressure of the mixture.

Abstract: A Machine for mixing elastomeric materials with a mixing unit, and a drive unit; the mixing unit has a mixing chamber arranged downstream of the drive unit and closed by a rear wall, a discharge chamber arranged downstream of the mixing chamber, with which it communicates and provided with an opening for discharging the mixture; a pair of inter-penetrating and counter-rotating conical rotors connected with the drive unit and having their vertices situated at the mouth of the discharge chamber. The rotors are rotated by the drive unit in a first sense (RPM+) to cause the mixture to be pushed towards the rear wall of the mixing chamber so as to keep mixing active only inside the mixing chamber, and in second sense of rotation, opposite to the first sense, to cause the mixture to be pushed towards the chamber and the discharge opening for discharging thereof.

Abstract: A machine for mixing elastomeric materials with a drive and mixing unit where the mixing chamber is arranged downstream of the drive unit; and a discharge chamber is arranged downstream of the mixing chamber. They communicate towards upstream, and are provided with a discharge opening for discharging the mixture. They include a signal indicating the presence or absence of a mixture. The machine can cause during a mixing step, at least one reversal by the drive unit of a sense of rotation of the rotors and therefore of a sense of advancing movement in the axial direction of the mixture from/towards the mixing chamber and towards/from the discharge chamber, to keep mixing of the mixture active only inside the mixing chamber.

Abstract: The invention relates to an extruder with two screws, a first screw and a second screw each comprising a threaded conical shaft having a first end with a bigger diameter and a second tapered end, said screws being arranged converging towards each other for the extrusion of plastomers, elastomers and viscous liquids in general. According to the invention, said first screw has a corresponding thread with a first portion which is diametrically larger than a corresponding first portion of the thread of the second screw.

Abstract: Rotor (5) for machines (1) mixing elastomers and the like, comprising a first section of greater axial length (L1), defining a thrusting flange (6), and a second section of smaller axial length (L2), defining a counter-thrusting flange (7), in which at least one of said thrusting flange (6) or counter-thrusting flange (7) has an angle of entry (&bgr;,&sgr;) into the mixture, which is varied along its extension.