Model of high pressure roller mills - a phenomenological-mathematical approach, Part 2

A phenomenological-mathematical model for high pressure roller mills is proposed for investigating the behaviour of the particle bed during high pressure grinding. The model is based on material parameters (e. g. coefficients related to the compression and expansion behaviour of the particle bed), which are governed by the material to be crushed, machine parameters (e.g. diameter; length of rolls), which are determined during the design stage and cannot be changed during the operation of the mill, setting parameters (e.g. circumferential velocity of the rolls, grinding force or gap), which are set during the commissioning and/or operation of the mill within the framework which has been determined during the design stage. These parameters are linked together by the balance of forces acting in and on the particle bed between the rolls. The model then yields the operating parameters (e.g. capacity and energy consumption of the mill, torque of the rolls, bulk density of the flake), which will result from the operation of the mill. The model also makes it possible to determine the particle distribution of the pressure and shear at the contact interfaces between the rolls and the particle bed.