Patent ID: 8706287
Filing Date: 2014-04-22
Classification: B02C

Abstract:
1. A mill control system for a coal mill, said mill control system comprising: a mill control apparatus for controlling mill characteristic variables including grinding pressure and sifter rotation speed, the mill control apparatus including a grinding pressure control unit that controls the grinding pressure of grinding rolls in response to mill load, and a sifter rotation speed control unit that controls sifter rotation speed in response to the mill load, and a device for detecting an air pressure difference between air pressure upstream of the mill and air pressure downstream from the mill, a fuzzy control apparatus connected to the mill control apparatus, the fuzzy control apparatus being configured for controlling nominal variables of the mill characteristic variables, the fuzzy control apparatus having a first fuzzy control unit that controls a grinding pressure nominal variable, and a second fuzzy control unit that controls a sifter rotation speed nominal variable, wherein the fuzzy control apparatus is designed to adjust the nominal variables of the mill characteristic variables, including the grinding pressure and sifting rotation speed, to be controlled, in the event of a discrepancy between a mill operating parameter and a predefined normal range corresponding to the mill load, the mill operating parameter being an air pressure difference between the air pressure upstream of the mill and the air pressure downstream of the mill, said fuzzy control apparatus being configured to adjust said nominal variables as a function of fuzzy rules that are based on the mill operating parameter until the mill operating parameter has reached the predefined normal range again wherein the mill control apparatus adopts the adjusted nominal variables of said mill characteristic variables as the new nominal variables and then controls said mill characteristic variables on the basis of the newly selected nominal values.