Counter-rotating differential speed extrusion device, extruder and method for manufacturing materials

A counter-rotating differential speed extrusion device, comprising a barrel and a screw mechanism arranged in the barrel, the screw mechanism comprising a first screw and a second screw,

• wherein a crest diameter and a root diameter of the first screw are respectively meshed with a root diameter and a crest diameter of the second screw;
• the first screw and the second screw are configured for counter-rotating in differential speeds at a fixed rotation speed ratio;
• at least one first intermediate circular arc structure is provided between the root diameter and the crest diameter of the first screw, a second intermediate circular arc structure that is tangent to the first intermediate circular arc structure is provided between the root diameter and the crest diameter of the second screw;
• a trend of the first intermediate circular arc structure is consistent with a thread trend of the crest diameter and the root diameter of the first screw;
• a trend of the second intermediate circular arc structure is consistent with a thread trend of the root diameter and the crest diameter of the second screw;
• wherein the first intermediate circular arc structure is disposed on one side or both sides of the crest diameter of the first screw, and the second intermediate circular arc structure is also disposed on one side or both sides of the crest diameter of the second screw;
• the first intermediate circular arc structure and the second intermediate circular arc structure are jointly used to open a screw groove of the first screw and a screw groove of the second screw to each other, and form an “8”-shaped chamber positive displacement conveying unit.