Reducing in surging in shredders : final report 2019/204

Abstract

Cane shredders and the level of cane preparation achieved by them play a significant role in the performance of every mill’s extraction train. The application of feeder rolls to shredders has a twofold objective of increasing the angle of wrap and maintaining a uniform feed of cane into the shredder. In addition to these improvements that were observed in several experiments across the Australian mills, there have been reports on other benefits of using feeder rollers including reduction of deterioration in shredders. Feeder rolls are currently installed in half of the Australian sugar mills. However, there exists several challenges with operating feeder rolls including inconsistency in feeding rate. Limited research effort has been made to identify a design and setting which yields adequate feeding consistency. Most of the previous research focused on feeder rolls dates back to the 1980s and 1990s confirming that the influence of geometric factors on feeding behaviour is well worthy of investigation.

A specific problem has also been occurring at Tableland mill where the cane shredder experiences surging. The major consequence of surging is lower cane preparation since, to prevent stalling, the shredder grid setting is increased. This issue is particularly of concern in shredders driven by electric motors, since electric motors have less inertia to overcome increases in torque due to surging and the peaks in torque have a greater impact on motor life than they do on turbine life. It Is likely that electrically driven shredders will become more common in the future as mills seek increased energy efficiency, increasing the significance of this issue in the future. Surging has also been identified as an issue on some shredders driven by turbines.

This project provided an opportunity to review the current design of feeder rolls, experimentally investigate their performance and will assist in developing design and operation guidelines useful to the Australian sugar industry.