Method for controlling the material feed to a roller mill and such mill

Abstract

A description is given of a method for controlling the material feed to a roller mill for continuous grinding of particulate material, such as cement raw materials, cement clinker and similar materials, which roller mill comprises a substantially horizontal grinding table (1) and a number of rollers (2) operating interactively therewith, said rollers rotating about separate roller shafts (3) which are connected to a vertical central shaft (4) via a hinged connection (5) allowing a free circular movement of the roller up and down in a plane comprising the centreline (6) of the roller shaft, where material to be ground is continuously fed to the roller mill, with ground material being continuously diverted from the roller mill. The method is peculiar in that an angle (α) between at least one of the roller shaft centrelines (6) and a reference line (18) is measured and used as an input signal for a control circuit for controlling the material feed. Hereby is obtained a fast and adequate control of the material feed which takes due account of the immediate operating environment in the roller mill in terms of material charge, le the amount of material present in the roller mill at any given time. This is due to the fact that variations in the angular positions of the roller shafts will provide a prompt and significant indication of any tendency towards overfilling or emptying of the mill.