Patent ID: 6466839
Filing Date: 2002-10-15
Classification: D21G,Y10S

Abstract:
A system for controlling a sheetmaking machine which forms a dry sheet product from a wetstock material, said sheetmaking machine being made up of machine elements including a wetstock source for providing wetstock to a headbox, said headbox for dispensing wetstock onto a traveling mesh conveyer, said conveyer providing for a draining process of liquid from said wetstock, and forming elements positioned essentially beneath said conveyer at the impingement region of said wetstock onto said conveyer, said machine elements of said sheetmaking machine having associated adjustable operating variables for affecting dry basis weight of said sheet product, said control system comprising:a sensing means positioned in close proximity to said conveyer for simultaneously detecting at multiple points on said conveyer a basis weight of said dispensed wetstock, said sensor providing independent machine direction and cross direction basis weight measurements; a means for predicting independent cross direction and machine direction dry end sheet product basis weight of said dispensed wetstock at said multiple points using said independent machine direction and cross direction basis weight measurements; control means for receiving said predicted dry end basis weight measurements and generating control signals for controlling said operating variables of said sheetmaking machine elements, said control signals including at least one of a cross direction related control signal and a machine direction control signal that is coupled to said wetstock source for controlling specific energy of a refiner by adjusting a refiner motor load control signal.