Patent ID: 9309625
Filing Date: 2016-04-12
CPC Classification: D21G

Claim Text:
1. A control system for a sheet making machine having a wet end that comprises a wire and a dry end, the wet end having manipulable elements which are adjusted to maintain properties of the sheet at the wet end, which properties effect measurable properties of the sheet that comprises paper at the dry end, and the dry end having sensors which develop electrical signals to convey quantitative information of the measurable properties, the control system comprising: a dry end controller responsive to the measured values of properties of the sheet at the dry end developed by the sensors and operative to develop setpoint signals for properties of the sheet at the wet end, each of the setpoint signals quantitatively establishing a setpoint of a respective one of properties of the sheet at the wet end; a wet end controller responsive to the setpoint signals for the wet end properties and operative to manipulate the wet end elements commensurately with the setpoints; and an estimator responsive to the measurements developed by the sensors and to further signals which convey quantitative information of present values of the inputs to the wet end to develop estimated values of wet end properties at the wire and said estimator includes a wire dry weight estimator, a wire ash weight estimator and a percent ash calculator, said estimated wet end property signals being commensurate with an estimated dry weight and an estimated percent wire ash relating to the corresponding measurable properties of dry weight and ash percentage at the dry end; wherein in the event the setpoint signals are not currently available to establish the wet end setpoints the wet end controller being further responsive to the estimates of the wet end properties and operative to manipulate the wet end elements.