Mixer Evaluation Using an Independent Drive

When comparing mixing devices by measurement of striation thickness in the extrudate, under normal extruder arrangements the results are for overall mixing by both extruder screw and attached mixer. A particular variable is the influence of back pressure due to the mixer on both melting rate and mixing in the screw channel. 

There were two further advantages for this configuration  

1) Power consumption (from torque and speed measurement) can be more accurately measured by separating the mixer drive from that of the extruder. When measurements were made with a wattmeter attached to an extruder, the increase in power consumption due to the mixer was too small to give a significant 

2) By varying the mixer speed independently of the extruder output, a better 

Polymers used were LDPE, HDPE and polypropylene (PP). 

---