초록 ▼

An extruder for plasticating and extruding an extrudate, and an extrusion screw used with the extruder form the subject of this invention. The extruder screw includes an elongated root body and a thread portion helically wound about the root body and extending along the length. The screw having a lo

An extruder for plasticating and extruding an extrudate, and an extrusion screw used with the extruder form the subject of this invention. The extruder screw includes an elongated root body and a thread portion helically wound about the root body and extending along the length. The screw having a low compression ratio, flight with a reduced helical angle, and a conical, tapered front end section where at least one-half flight of the thread has a pitch associated therewith which is different from the pitch of the remainder of the thread and where the diameter is less than the diameter of the remainder of the root body.

대표청구항 ▼

[ Therefore, we claim:] [1.] An extruder for plasticating and extruding an extrudate, comprising:an elongated barrel defining an interior elongated cylindrical passage of generally constant diameter;an elongated extrusion screw received in the interior cylindrical passage of said barrel, said extrus

[ Therefore, we claim:] [1.] An extruder for plasticating and extruding an extrudate, comprising:an elongated barrel defining an interior elongated cylindrical passage of generally constant diameter;an elongated extrusion screw received in the interior cylindrical passage of said barrel, said extrusion screw including an elongated root body and a thread portion helically wound about said root body and extending along the length thereof, the elongated root body having a generally constant diameter, said extrusion screw defining a conical, tapered front end section having a minimum diameter at the front end of the screw, the taper of said conical, tapered front end section having a diameter reduction of at least 40% at the front end of said conical tapered front end section in comparison with the diameter of said root body, at least the last one-half revolution of the flight of said thread portion has a pitch associated therewith which is different from the pitch of the remainder of said thread portion, and where said conical, tapered front end section defines with said interior cylindrical passage a region of increased volume;means for rotating said extrusion screw relative to said barrel;means for supplying material to be plasticated to said interior elongated passage; andmeans for heating said barrel and thereby the material to be plasticated as the material to be plasticated is moved through said interior elongated passage by the rotation of said extrusion screw.