A torpedo for an extruder comprises: longitudinal member (9) which is provided at the periphery thereof with a plurality of thread portions (12) which protrude outwards and which are spaced apart in the circumferential direction; a plurality of sluice blades (19) which are mounted so as to be movable on the longitudinal member and which are partially engaged in apertures (18) of the longitudinal member, the longitudinal member (9) and the sluice blades (19) being provided with complementary radial guiding surfaces (13, 14, 18) which are in contact with each other; and adjustment means (28) for radially displacing the sluice blades relative to the longitudinal member. The sluice blades extend through the spaces between the thread portions, respectively. The thread portions (12) and the sluice blades (19) are provided with complementary radial guiding surfaces (13, 14, 18).

High Specific Mechanical Energy extruder screw assemblies (14, 88, 98) and complete extruders (10, 86, 96) are provided, which include wide-flight intermediate screw sections (104) having axial flight widths greater than the flight widths of the inlet and outlet screw sections (102, 106) on opposite sides of the intermediate sections (104). The intermediate sections (104) provide increased friction and shear serving to enhance the SMEs imparted to comestible food materials during processing thereof.

A screw to be used in an extruder has a modular structure so that it can be adapted very flexibly to new tasks and conditions. The modular structure of a screw contains a rod-shaped mandrel and individual screw components which are slidable onto the mandrel. The components perform the classic functions of the screw during the extrusion process, such as conveying, kneading, mixing or shearing of the plastic to be guided into and through the plant.

For transmission of the occurring high torque, the components are connected with the mandrel so that they positively engage and are axially braced in addition. The connection is to be performed such that it can be released by simple means.

A screw used in an extruder and an extruder having such a screw, in particular a screw used in a multiple-screw extruder and a multiple-screw extruder uses an additional connecting element directly leading from one segment to the next in order to relieve the mandrel. The screw includes a mandrel and a plurality of segments borne by the mandrel and arranged axially with respect to one another, a segment border between a first segment and an axially adjacent second segment has a separate cylindrical connecting element adapted to transmit a torque over the segment border. The ratio of a length of the connecting element to the diameter of the connecting element is higher than 11.

A conveyance portion, a barrier portion, and a path are provided at places of a screw main body in which a kneading portion is provided. In at least one of the places, the path is provided inside the screw main body, and includes an entrance and an exit. The entrance is opened to urge the raw materials having the conveyance limited by the barrier portion to increase pressure on the raw materials, to flow in the entrance. The raw materials flowing from the entrance flow through the path in the same direction as a conveyance direction of the conveyance portion.

At a part of the screw main body at which the kneading portion is provided, conveyance portions, a barrier portion and a path are provided at a plurality of places. At least one of the places, the path is provided inside the screw main body, and includes an entrance and an exit. The entrance is opened in such a manner that the raw material whose pressure is enhanced by being restricted in conveyance by the barrier portion flows into the entrance. The path is formed in such a manner that the raw material flowing into the path from the entrance flows toward the exit in a direction opposite to the direction of conveyance.

Puck and collar alignment device embodiments facilitate simultaneous insertion of free end portions of screw shafts into open end portions of complementary drive couplings. The embodiments have alignment keys that correct deviations in alignment and rotation introduced while moving the screw shafts though a barrel of an extruder. Tapered front faces of the alignment keys incrementally adjust coaxial alignment, and tapered side faces of the alignment keys incrementally adjust rotational position cooperatively between the alignment devices and drive couplings. The coaxial and rotational position adjustments cooperate to simultaneously guide multiple alignment keys to fit within corresponding keyway sections while providing alignment of external splines on the screw shafts to interlock in a timed relationship with internal splines on the drive couplings during the simultaneous insertion.

An extruder screw including an elongated cylindrical tension rod; screw segments including radially protruding functional elements configured to feed, mix, and/or knead an extrudate, and a respective pass through bore hole oriented in a longitudinal direction of the extruder screw, wherein the screw segments are slid onto the tension rod with the pass through bore hole and axially supported at a tip of the tension rod; a counter element that clamps the screw segments against the tip of the tension rod at an end of the tension rod wherein the end is arranged distal from the tip; and a locking element that is clamped between the screw segments and the counter element.