Abstract: The present invention relates to apparatuses and methods for measuring and controlling the amount of multiple coating materials applied to a substrate, and in particular to an apparatus and method for monitoring and regulating the amount of multiple coating materials containing different compositions applied to a substrate, such as paperboard. The coating measurement is insensitive to changes in both the amount of substrate as well as in the amount of an interfering component associated with the substrate.

Abstract: A nuclear gauge for making measurements of traveling webs in continuous sheet-making processes includes an enclosure, an encapsulated nuclear source, and a wheel-like member mounted in the enclosure means for carrying the encapsulated nuclear source between two angularly-displaced positions. The first of the angularly-displaced positions is the position where the encapsulated nuclear source makes measurements of a web that travels past the gauge and the second position is the location where the encapsulated nuclear source faces a sidewall of the enclosure means at a location remote from the first position. The nuclear gauge also has an aperture which is formed through the enclosure for providing a window through which the encapsuled nuclear source, when located in the first position, can emit radiation onto a web that travels past the window.

Abstract: A sensor, system and method for determining the various Z-directional properties of a sheet by measuring the caliper of a moving sheet of material at a plurality of pressures. The invention employs a caliper gauge and a set of pressure transducers that can measure and send signals indicative of the caliper as well as pressures exerted on the sheet. The signals are then digitized by an analog-to-digital converter and sent to a computer. The computer uses the compressibility data to construct a compression stress-strain diagram where the slope of the curve in the linear 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 be then used in various formulas to determine other Z-directional physical properties of the sheet, such as tensile strength, extensional stiffness and Scott bonding.

Abstract: A sensor and method is provided for measuring one or more select components of a material. In one embodiment, a method measures the components by emitting electromagnetic radiation at the material and detecting the intensity of the emerging radiation at separate locations from the source. In another embodiment, a sensor provides a radiation source for emitting radiation at a sheet, a plurality of detecting means, offset substantially the same from the source, for detecting radiation after interaction with the sheet and first and second reflectors for directing the radiation so that the radiation makes multiple interactions with the sheet when moving from the source to the detecting means. The invention can accurately measure the select components (e.g., moisture) of different grades of paper by eliminating the effects of the scattering power and determining absorption power at each band of the spectrum considered necessary for a particular measurement.

Abstract: A sheet manufacturing system having a steam profiling bar, a moisture profiling bar, a moisture sensor and a computer is disclosed. The computer is programmed to cause the correct amount of steam or water to be applied on a slice-by-slice basis based upon the moisture content profile data generated by the moisture sensor as compared against a preprogrammed, desired moisture content profile. The computer is programmed in such a way as to cause either steam or water, but not both, to be applied as needed to any given portion of each individual slice to achieve the desired moisture content profile. Thus, the combined application of both steam and water to the same portion of the sheet, and the nullifying effects thereof, are avoided, resulting in the use of less steam and less water while still providing full control over the moisture content profile with only one moisture sensor.

Abstract: A device for characterizing the formation of a sheet material is described. The device comprises a formation sensor for measuring the basis weight of the sheet material as the material passes through the sensor, and signal processing circuitry which receives a basis weight signal from the formation sensor and which produces three types of outputs, which outputs characterize: (1) the magnitude of variation in the sheet basis weight; (2) the strength of the weakest portion or portions of the sheet; and (3) the size of the flocs comprising the sheet. The formation sensor includes a light pipe that is held against the sheet as the sheet moves through the sensor, and that directs a small spot of light transmitted through the sheet to a light detecting device. The magnitude of small-scale variation in the sheet basis weight is computed by determining the ratio between average value of the basis weight signal and the varying or AC component of the basis weight signal.

Abstract: A sensor and method is provided for measuring one or more select components of a material. In one embodiment, a method measures the components by emitting electromagnetic radiation at the material and detecting the intensity of the emerging radiation at separate locations from the source. In another embodiment, a sensor provides a radiation source for emitting radiation at a sheet, a plurality of detecting means, wherein at least one detecting means is offset from the source, for detecting radiation after interaction with the sheet and first and second reflectors for directing the radiation so that the radiation makes multiple interactions with the sheet when moving from the source to the detecting means. The invention can accurately measure the select components (e.g., moisture) of different grades of paper by eliminating the effects of the scattering power and determining absorption power at each band of the spectrum considered necessary for a particular measurement.

Abstract: A contacting caliper gauge measures the thickness of a moving sheet material. The gauge has two heads, one on either side of the sheet. The sheet contacting pads of the caliper gauge are aerodynamically designed to limit and/or reduce the tendency of boundary layer air travelling with the sheet to raise the sheet-contacting pads off of the sheet surfaces.

Abstract: A method for determining bending stiffness of a moving sheet using an on-line sheet bending stiffness sensor. The sensor continuously bends the sheet as it is being manufactured and, based upon the force required to bend the sheet, the amount of bending and the tension applied to the sheet, the sensor determines a parameter indicative of sheet bending stiffness. The resulting parameter can be correlated with conventional destructive laboratory tests of sheet bending stiffness.

Abstract: A sheet-gauging apparatus for determining properties of a moving sheet of material includes a frame having parallel upper and lower horizontal supports extending above and below the sheet in a direction transverse to the direction of travel of the sheet. Upper and lower tracks are carried by the upper and lower supports, respectively, each of the tracks including a flat upper surface and a lower surface having tapered end portions. Upper and lower carriages are mounted on the upper and lower tracks, respectively, for bidirectional travel along the tracks, each of the carriages including upper wheels in rolling contact with the upper surface of the track and lower wheels in rolling contact with the tapered end portions of the lower surface of the track. Displacement of the carriages in the directions orthogonal to the direction of carriage travel is thereby minimized.

Abstract: An on-line scanning sensor system includes a mid-infrared spectrophotometric analyzer, such as an interferometer, that can be used on-line in manufacturing environments. More particularly, the on-line scanning sensor system includes a first carriage for scanning motion across a traveling sheet of material; interferometer components that are carried by the first carriage and that includes devices for splitting and recombining infrared light, and for directing a collimated beam of the recombined light onto a traveling web of sheet material. Further, the system includes a detector system for receiving light from the interferometer components during scanning.

Abstract: Apparatus utilized in the continuous manufacture of sheet material, such as paper, includes a frame having at least one hollow beam for carrying means such as sheet-gauging heads operatively associated with the sheet material being fabricated. Thermal stability of the at least one hollow beam is enhanced by circulating fluid within the beam. Fluid displacement means which may be in the form of a series of inserts disposed end-to-end within the hollow beam define with the interior wall of the beam a fluid conduction channel. The fluid displacement means may also include generally helically oriented guides projecting into the fluid conduction channel for inducing turbulence in the circulating fluid.

Abstract: A system for at least partly decoupling the control of sheet finish and sheet caliper in a calender stack is disclosed. The system includes a heating device for heating the sheet with dry heat substantially immediately before the sheet is pressed by an upstream nip of the calender stack and a moisturizer for moisturizing the sheet substantially immediately before the sheet is pressed at a downstream nip of the calender stack. The sheet is moisturized without substantially altering the sheet temperature.

Abstract: A sensor for detecting directional variations in a physical characteristic of a moving sheet of material is disclosed. The sensor has a support for supporting the moving sheet. The support defines an open region into which the moving sheet is deflected by a deflector. Detectors coupled to the support detect and produce signals indicative of the force exerted on the support by the deflected sheet in at least three different directions. Each signal is processed to determine a physical characteristic, such as extensional stiffness, of the sheet of material in each of the three directions. The directional variations of the physical characteristic may be used to determine the fiber orientation angle and the degree of anisotropism of the sheet.

Abstract: An infrared web moisture sensor which is substantially temperature and basis weight insensitive comprises a source of infrared radiation for directing an infrared beam through the web and an infrared detecting unit on the other side of the web which measures the transmission of the infrared beam through the web at three separate wavelength regions. The transmission in the first wavelength region is primarily sensitive to the moisture content of the web. The transmissions in the second wavelength region is less sensitive to the moisture content. The transmission in the third wavelength region provides an indication of the web temperature. Temperature insensitivity is achieved by selecting the temperature response of a measurement band pass filter and a reference band pass filter based on the maximum basis weight and the maximum moisture content of the web and compensating for any remaining temperature sensitivity with a temperature correction band pass filter.

Abstract: The invention provides multiple steam applicators which are used to distribute steam against a web during calendering. The invention includes a primary steam applicator located adjacent a side of the web to which steam is applied. The primary steam applicator has a manifold, a primary inlet valve, and a plurality of steam valves spaced along the primary manifold. Each steam valve regulates a steam flow distributed to a cross-directional section of the web. A secondary steam applicator is located adjacent the side of the web to which steam is applied. The secondary steam applicator has a manifold, a secondary inlet valve, and a plurality of steam valves spaced along the secondary manifold, each steam valve regulating a steam flow distributed to a cross-directional section of the web. A gloss sensor measures the gloss finish of the web.

Abstract: A time delay compensation control system for use in controlling a sheetmaking process includes a controller operated according to the Smith Predictor control scheme and means to automatically adjust the closed-loop time constant of the controller in inverse relationship to the system error or to the signal-to-noise ratio of the system output signals.

Abstract: A system for controlling deflections of an elongate body transverse to a longitudinal axis of the body, the system including: a sensor mounted on the body for producing an output signal when the body experiences a deflection in at least one direction transverse to its axis; heating and/or cooling elements thermally coupled to the body at a location for heating or cooling the body in a manner to thermally deflect the body in a direction transverse to the longitudinal axis; and a control unit, connected between the sensor and the heating or cooling elements, responsive to the output signal produced by the sensor.

Abstract: A running blade is adapted to move at the same speed as a continuously running sheet and to generate a burst perforation through the sheet. The force exerted by the blade against the sheet is measured and used to calibrate a non-destructive sheet strength sensor.

Abstract: An apparatus for controlling the cross-directional smoothness profile of the surface of a calenderable material substantially independently of the materials's caliper profile. A plurality of adjustable nozzles selectively direct jets of steam of selected velocities against sections of the material across the material's width and in counterflow to its movement, immediately before the material enters the last nip of a calender stack. Built-in steam control valves are provided to control the amount of steam applied to each section. Suction means may also be provided upstream of the nozzles, with reference to the movement of the calenderable material, to remove excess steam and thus prevent undesirable condensation on adjacent structures. The smoothness profile may be monitored and compared to a desired smoothness profile and the valves and nozzles may be adjusted accordingly.