PERFORATED MILL ROLL SHELLS

PERFORATED SUGAR MILL roll shells contain a system of radial drainage passages connecting the surface of the roller to a set of longitudinal internal manifolds with open ends. The intention is that these perforated roll shells provide additional drainage paths for the juice extracted by the crushing mill. The claimed advantages of perforated rolls over solid rolls included improved mill feeding, increased extraction and reduced bagasse moisture. The paper reports previously unpublished trials undertaken in the 1990s with the aim of establishing the performance of perforated roll shells relative to that of conventional, solid roll shells when installed in the top roll position of 6-roll mills. The work did not identify any strong performance advantage of perforated roll shells in the situations tested. Provision of the drainage holes adds to the cost of a roll shell and may reduce its useful life. Problems were experienced with blocking of the drainage holes. Potential for juice to leak back out of the drainage holes into the discharge bagasse was also identified.