Chopper systems in cane harvesters: B: results of a test program

A test program to assess the performance of cane-harvester rotary-pinch chopper systems was undertaken with selected chopper units supplied by harvester manufacturers and after-market chopper system manUfacturers. While the test program was undertaken on a commercial-in-confidence basis, a number of findings are of universal significance to the industry. Cane and juice losses in the chopping process averaged 3.4% across all chopper systems tested, and ranged as high as 7.2% with optimal system setup for individual tests. Cane and juice losses are dramatically increased as knives become blunt. The results from all chopper systems demonstrate that pour rate and cane cultivar are the most significant variables impacting on both losses and billet damage during billeting. Reducing the nominal feed-train speed to shorten billet length, a common practice, also increased losses. This research has shown that cane losses can be minimised and billet quality improved by operating at conservative pour rates, utilising higher feed-train roller speeds, and maintaining an even supply of cane through the feed-train. Further research is necessary to investigate the impact of the design of rotary chopper systems on cane loss and billet quality.