Abstract:
A system for aligning control zones (S1, S2, S3, S4, S5) with measurement zones (S1', S2', S3', S4') in a sheet-making system having a plurality of actuators (23) arranged in the cross-direction, comprising the steps of: a) bumping at least one of the actuators; b) measuring a profile of the sheet at a substantial distance from the bumped actuators; and c) determining a location of the effect of each of the bumped actuators on the sheet.
Abstract:
A sensor (12) system and method for determining the various Z-directional properties of a sheet (14) by measuring the caliper of a moving sheet (14) of material at a plurality of pressures. The invention employs a caliper gauge (10) and a set of pressure transducers (not shown) that can measure and send signals indicative of the caliper as well as pressures exerted on the sheet (14). The signals are then digitized by an analog-to-digital converter (not shown) and sent to a computer (30). The computer (30) uses the compressibility data to construct a compression stress-strain diagram where the slope of the curve in the linear region of the region of the curve is defined as the compression modulus of elasticity which can be empirically correlated to the tensile modulus of elasticity for various grades of paper. The tensile modulus of elasticity can then be used in various formulas to determine other Z-directional physical properties of the sheet (14) such as tensile strength, extensional stiffness and Scott bonding.
Abstract:
A system for controlling calendering roll diameters in continuous sheetmaking systems includes profile actuators (27) spaced from one another at generally decreasing distances (D1>D2>D3>...>DN) along a plenum (25) which extends from edge to edge of the sheet. The largest spacing (D1) between nozzles is at locations corresponding to the center of the sheet.
Abstract:
A two-dimensional position detector, in combination with dynamic z and/or flutter sensors, provides dynamic misalignment detection and correction of a measuring head, thereby allowing accurate determinations to be made of properties of a sheet material, such as basis weight.
Abstract:
A distributed intelligence control system for controlling a cross direction profile of a traveling sheet (10) includes a scanner (12) for measuring a property of the sheet at a plurality of cross direction locations and producing output signals indicative of the cross direction profile. A host controller (20) coupled to receive the signals from the scanner (12) produces signals representing desired profile information. The system includes a plurality of actuators (26), each actuator being operatively associated with a corresponding intelligent actuator controller (30). A local area network (22) provides a bidirectional communication link between the host controller and the intelligent actuator controllers and between adjacent actuator controllers, the network transmitting to the actuator controllers the desired profile information from the host controller and transmitting between adjacent actuator controllers actual actuator state information, the intelligent actuator controllers calculating target positions based upon the transmitted information.
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 higly 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. The intensity of the flashlamp is electronically controlled to maintain the balance of UV to visible light that characterizes the standard source. The color sensor further includes a sheet backing system including a rotatable standard wheel carrying a white standard tile. Provision is made to permit rotation of the standard wheel and to standardize the sensor off-sheet while maintaining isolation of the white standard tile from the paper mill environment. The sheet backing system includes a paper guide plate defining an annular vortex space into which air is introduced from a pressurized source. A low pressure region thereby produced in the vortex space draws the paper sheet toward the guide plate. At the same time, circulating air spirals outwardly from the vortex space to form a thin air film or air bearing between the sheet and the paper guide. Sheet flutter is thereby minimized and damage to the sheet is prevented.
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. The intensity of the flashlamp is electronically controlled to maintain the balance of UV to visible light that characterizes the standard source. The color sensor further includes a sheet backing system including a rotatable standard wheel carrying a white standard tile. Provision is made to permit rotation of the standard wheel and to standardize the sensor off-sheet while maintaining isolation of the white standard tile from the paper mill environment. The sheet backing system includes a paper guide plate defining an annular vortex space into which air is introduced from a pressurized source. A low pressure region thereby produced in the vortex space draws the paper sheet toward the guide plate. At the same time, circulating air spirals outwardly from the vortex space to form a thin air film or air bearing between the sheet and the paper guide. Sheet flutter is thereby minimized and damage to the sheet is prevented.
Abstract:
An on-line laser triangulation position sensing system provides measurements of the surface features of a moving sheet such as paper. The measurements are correlatable with measurements made with standard laboratory surface smoothness testers and provide predictions of the printability of paper during its fabrication. The sensing system includes a segmented balance detector having a high frequency response. The sensing system further includes signal processing circuitry comprising a plurality of channels, each channel including a filter. The various filters have different cutoff frequencies for passing different frequency spectra representing ranges of surface feature scale sizes. The cutoff frequency of each filter is varied in response to variations in sheet speed. The sheet sensing system further includes a sheet stabilizer to minimize flutter in the measurement region and a standardizing member permitting performance verification of the sensor system at at least one scale size spectrum. The sensing system may also be provided with a sheet compressor to compress the sheet in the measurement region so as to simulate the pressures applied to sheet samples by laboratory air leak smoothness testers. The output of the position sensing system may be used in conjunction with various kinds of papermaking machines to control one or more of the many papermaking process parameters that determine the smoothness or texture of the final product. The sensing system can be used to measure tissue crepe and such measurement can be utilized to control various crepe-determining stages in a tissue making machine and to monitor the condition of the creping or doctor blade in such a machine.
Abstract:
The present invention relates to apparatuses and methods for measuring and controlling the amount of multiple coating materials applied to a substrate (12), and in particular to an apparatus (10) and method for monitoring and regulating the amount of multiple coating materials (24 and 25) containing different compositions applied to a substrate (12), such as paperboard. The coating measurement is insensitive to changes in both the amount of substrate (12) as well as in the amount of an interfering component associated with the substrate (12).
Abstract:
A sensor (10) for detecting directional variations in a physical characteristic, fiber orientation angle and the degree of anisotropism of a moving sheet of material is disclosed. The sensor (10) has a support (12) for supporting the moving sheet (14). The support (12) defines an open region into which the moving sheet (14) is deflected by a deflector (16). Detectors (20) coupled to the support (12) detect and produce signals indicative of the force exerted on the support (12) by the deflected sheet in at least three different directions. Alternatively, the support (112) may be rotatable to allow detectors (120) coupled to the support (112) to detect and produce signals indicative of the force exerted on the support (112) by the deflected sheet (114) in a number of different directions. Each signal is processed to determine a physical characteristic, such as extensional stiffness, of the sheet of material in each of the at least three directions.