A mixing element for screws of extruders with two co-rotating screws and an extruder comprising the mixing element

摘要

The mixing element (10) has a central hole (12) for keying to the shaft (26) of the screw and an outer profile (14) which can be produced as a result of the removal of material from a circular element along at least one arc of its outer portion by cutting performed by a point-like element rotating around a circle with a diameter equal to that of the circular element. The point-like element and the circular element rotate in the same direction and at the same speed and the centres of the circular element and of the circle are spaced apart by a distance less than their diameter. During a portion of the cutting process, the distance between the centres of the circular element and of the circle is reduced so that the portion (18) of the outer profile (14) which is correspondingly cut is recessed.