Abstract: System and method for producing paper that employ an apparatus for measuring electrical characteristics of a fibrous composition. The apparatus comprises a plurality of conductivity (or resistance) detectors each comprising a sensor that is sensitive to the conductivity (or resistance) and the proximity of the material (e.g., fibrous composition) to the sensor. Measurements from the apparatus relate to the zeta potential of the fibrous materials in the composition. The zeta potential profiles corresponding optimized configurations of the sheetmaking process can be employed to monitor and control the process.

Abstract: Significant improvements in papermaking control can be achieved by employing an array of sensors that are positioned underneath the wire of the machine to measure the conductivity of the aqueous wet stock. The conductivity of the wet stock is directly proportional to the total water weight within the wet stock; consequently, the sensor provides information which can be used to monitor and control the quality of the paper sheet produced. Because CD water weight profile is obtained practically instantaneously, the MD and CD variations are essentially decoupled. Quality improvements to the sheet fabricated will be achieved by providing fast control of the actuators on the machine and by tuning components on the machine to eliminate the sources of variations.

Abstract: An apparatus and method for obtaining fiber weight measurements in the wet end of a sheetmaking system and for verifying fiber weight measurements taken in the wet end of a sheetmaking system which includes a water weight sensor positioned beneath the wire in the wet end of the sheetmaking system for obtaining water weight measurements and load cells residing beneath the water weight sensor for weighing the wet end sensor and the wire with wetstock (total weight) and without wetstock (tare weight). In one embodiment, the water weight measurement and the tare weight measurement are subtracted from the total weight to obtain the fiber weight in the wetstock. In another embodiment, the water weight measurement is used to obtain an predicted fiber weight measurement and the determined fiber weight is used to verify the predicted fiber weight measurement and the accuracy of the water weight measurement device.

Abstract: An apparatus for sensing three properties of materials: the conductivity or resistance, the dielectric constant, and the proximity of the material to the sensor portion of the apparatus. The apparatus includes a fixed impedance element coupled in series with the sensor portion of the apparatus between an input signal and ground. The sensor portion of the apparatus is an electrode configuration which includes at least two electrodes with a portion of the material residing between and in close proximity to the electrodes. The sensor exhibits a variable impedance resulting from changes in physical characteristics of the material. The fixed impedance element and the variable impedance of the sensor portion form a voltage divider network such that changes in impedance of the sensor portion results in changes in voltage on the output of the apparatus.

Abstract: Apparatus and process for controlling the basis weight of paper produced in a papermaking machine are provided. In the papermaking process, a major portion of the paper stock flows through a first line that is controlled by a thick stock valve and a minor portion of the stock flow from the stuff box to the headbox is diverted through a second line that is regulated by a second valve (e.g., vernier valve). The thick stock valve is controlled by the dry end basis weight and the second valve responsive to measurements of the basis weight of the wet stock at the wire. The second line and control valve along with the wet end basis weight measurements form a fine control loop with fast response time whereas the first line and control valve that is responsive to dry end basis weight measurements form a course control loop. The dual control loops enable fast and actual basis weight control.

Abstract: A system and method that combine an array of fast under wire water weigh sensors with a scanning system provides an accurate measurement of the entire sheet down to 1 in. by 1 in. resolution. Because CD profiles are obtained instantaneously, MD and CD variations are completely decoupled, even if CD profiles are taken at longer intervals apart.

Abstract: A control system regulates a controlled process. A first controller receives at least a first input variable and a second input variable and produces at least a first control variable and a second control variable. A delay unifier associated with the first controller introduces a first delay to one of the first and second control variables, the first delay being determined as a function of a second delay associated with another of the first and second control variables. A processor models effects of the controlled process. The processor receives the delayed first and second control variables output by the first controller and produces estimates of the process output variables. A second controller processes a difference between measured process output variables and the estimated process output variables to correct for disturbances.

Abstract: A method of predicting the dry stock weight of paper that is produced by a papermaking machine based on simultaneousness measurements of (1) the water weight of the paper stock on the fabric or wire of the papermaking machine and of (2) the dry stock weight of the paper product is provided. The invention which provides a linearized model of the de-watering process is based in part on that creation of drainage characteristic curves that provides an effective means of predicting the drainage behavior of the paper stock on the fabric of a de-watering system.

Abstract: A system and process are provided for determining the concentration of a first component of a mixture wherein the first component includes at least 3 materials. The process includes directing 2 beams of x-rays into the mixture and receiving portions of the beams which are transmitted through the mixture. The concentration of the first component is determined based upon the beams transmitted through the mixture.

Abstract: The present invention relates generally to the control of processes which include relatively long time delays, yet which are susceptible to transient external disturbances, such as high-speed sheetmaking processes. Exemplary embodiments include a control system architecture that combines internal model-based control with state feedback in a manner which provides robust control, yet provides rapid rejection of external transient disturbances even in processes including relatively long time delays.

Abstract: A sensor and a method for determining the basis weight of a coating material containing CaCO.sub.3 on a substrate is described. The determined basis weight is insensitive to changes in the amount of substrate material underlying the coating. Signals from the sensor may be used in the control of a coating mechanism to provide a coating having a uniform basis weight.

Abstract: Disclosed is an apparatus for measuring on-line the color and color-related properties of a moving sheet. Contrast ratio reflectance measurements are made for providing opacity corrections substantially in real time for a full color spectrum. An optical color sensor in accordance with the invention includes a pair of synchronized spectrometers, the first spectrometer being aligned to view a region of the sheet backed with a highly reflective ("white") material and the second spectrometer being aligned to view a region of the sheet backed with a highly absorptive ("black") material. The use of two spectrometers permits substantially simultaneous "black" and "white" measurements for a full color spectrum. The optical color sensing system further includes two light sources, a flashlamp and a continuously energized tungsten filament lamp. Light beams from the two sources are combined to form a sheet-illuminating third beam approximating the D65 standard source.

Abstract: A control system regulates a controlled process. A first controller receives at least a first input variable and a second input variable and produces at least a first control variable and a second control variable. A delay unifier associated with the first controller introduces a first delay to one of the first and second control variables, the first delay being determined as a function of a second delay associated with another of the first and second control variables, and outputs first and second control variables with unified delay. A processor models effects of the controlled process. The processor receives the delayed first and second control variables output by the first controller and produces estimated process output variables. A second controller processes a difference between measured process output variables and the estimated process output variables to correct for disturbances.

Abstract: A system and process are provided for determining the concentration of a first component of a mixture wherein the first component includes at least 3 materials. The process includes directing 2 beams of x-rays into the mixture and receiving portions of the beams which are transmitted through the mixture. The concentration of the first component is determined based upon the beams transmitted through the mixture.

Abstract: In a scanner used in a paper-making process to measure basis weight and other parameters of the fabricated paper sheet, variations in the separation of an opposed pair of sensing heads due to temperature induced deflections of upper and lower beams on which the heads are movably mounted as well as deflections and/or expansions of other portions of the support structure for the sensor are dynamically measured and compensated for. Temperature sensors mounted on carriages for the sensing heads measure the temperatures at different locations within the sensor support structure so that temperature differentials can be determined. The temperature differentials, which provide a measure of beam deflection at any given position of the head carrying carriage, are applied in accordance with a linearizing algorithm to correct the values provided by the sensing heads.

Abstract: An apparatus and method for controlling mass flow in an extrusion die provides cross-directional measurements of at least one property of an extrusion produced by the extrusion die, such measurements being made at a plurality of cross-directional locations that successively span the extrusion. The measurements are assembled to provide cross-directional profiles of the extrusion. A spatial-frequency splitter operates upon the cross directional profiles to separate selected spatial frequency component profiles from each cross-directional profile. A reference profile is provided for representing desired spatial frequency profiles. An error signal generator generates error signals representing the difference between the spatial frequency component profiles and the desired spatial frequency profiles and actuators control mass flow components of the extrusion die in response to the error signals.