Investigations into the movement of milled medium in the bowl of a ring-roller mill

This paper presents the results of testing the grind material movement in a ring-roller milling system. The tests were carried out in a 1:4 scale model of an RP-1043x`milling system. The aim of the test was to determine material bulk shapes within a range of parameter changes of a model grinding system i.e. table–roller distancing, pile-up ring height, coal feed and table's rotary speed. Based on the measurements of material layer thickness on the table, its average radial velocity was calculated. The results were then supplemented with tests based on the movement of markers over the surface layer of the coal bulk. These tests enabled the material's average radial and tangential velocities in the surface layer to be determined.

Graphical abstractBased on the measurements of the thickness of a bulk coal layer, several calculations were performed for the following parameters, i.e. average radial velocities for different rotary velocities of the table, feed stream, pile-up ring heights, and two different table–roller spacings. The results were then supplemented with test based on the movement of markers over the surface layer of the coal bulk. The test enabled the material's average radial and tangential velocities in the surface layer to be determined. A change in the table's rotary velocity results in an accumulation or release of a considerable part of the material. Thus, the rotary velocity may be a useful parameter in a mill control system.Figure optionsDownload full-size imageDownload as PowerPoint slide