HIGH PRESSURE LIQUID JET CUTTING SYSTEM AND METHOD FOR FORMING POLYMER PELLETS

摘要

A system and method for pelletizing extruded materials, such as thermoplastic polymers in various pelletizing applications, including underwater, hot face, and strand pelletizing applications, utilizes a high pressure liquid delivered to one or more nozzles which direct a high pressure liquid jet cutting stream at the extruded polymer strand to cut the strand into pellets. The system and method are particularly applicable to underwater pelletizers utilizing water or water-based solutions. In a preferred underwater pelletizing embodiment, a plurality of nozzles are mounted on a rotating nozzle hub which is fed high pressure water through sealed hollow pelletizer and hollow motor shafts. The high pressure water jet cutting streams exiting the rotating nozzles are preferably in the form of a flat V-shaped spray with a spread angle of about 15° to about 45° and an approach angle between 0° and 60°, depending upon the pelletizing application.